bluuebunny/crossref_metadata_2025 huggingface dataset:
COPII Sec23 proteins form isoform-specific ER exit sites with differential effects on polarized growth
Authors: Chang Mingqin , Wu Shu-Zon , Ryken Samantha E. , O’Sullivan Jacquelyn E. , Bezanilla Magdalena
Published: June 2020

COPII, a coat of proteins that form vesicles on the ER, mediates vesicle traffic from the ER to the Golgi. In contrast to metazoans that have few genes encoding each COPII component, plants have expanded these gene families leading to the hypothesis that plant COPII has functionally diversified. Here, we analyzed the gene families encoding for the Sec23/24 heterodimer in the mossPhyscomitrium (Physcomitrella) patens. InP. patens, Sec23andSec24gene families are each comprised of seven genes. Silencing the Sec23/24 genes revealed isoform specific contributions to polarized growth, with the closely relatedSec23D/EandSec24C/Dessential for protonemal development. Focusing on theSec23gene family, we discovered that loss of Sec23D alters ER morphology, increases ER stress, inhibits trafficking to the Golgi and to the plasma membrane in tip growing protonemata. In contrast, the remaining fiveSec23genes are dispensable for tip growth. WhileSec23A/B/C/F/Gdo not quantitatively affect ER to Golgi trafficking in protonemata, they do contribute to secretion to the plasma membrane. Of the three highly expressed Sec23 isoforms in protonemata, Sec23G forms ER exit sites that are larger than Sec23B and Sec23D and do not overlap with Sec23D. Furthermore, ER exit sites labeled by Sec23B or Sec23G form in the absence of Sec23D. These data suggest thatSec23D/Eform unique ER exit sites contributing to secretion that is essential for tip growing protonemata.
Rolling Circle Amplification is a high fidelity and efficient alternative to plasmid preparation for the rescue of infectious clones
Authors: Marano Jeffrey M. , Chuong Christina , Weger-Lucarelli James
Published: June 2020

Alphaviruses (genusAlphavirus; familyTogaviridae) are a medically relevant family of viruses that include chikungunya virus, Eastern equine encephalitis virus, and the emerging Mayaro virus. Infectious cDNA clones of these viruses are necessary molecular tools to understand viral biology and to create effective vaccines. The traditional approach to rescuing virus from an infectious cDNA clone requires propagating large amounts of plasmids in bacteria, which can result in unwanted mutations in the viral genome due to bacterial toxicity or recombination and requires specialized equipment and knowledge to propagate the bacteria. Here, we present an alternative to the bacterial-based plasmid platform that uses rolling circle amplification (RCA), anin vitrotechnology that amplifies plasmid DNA using only basic equipment. We demonstrate that the use of RCA to amplify plasmid DNA is comparable to the use of a midiprepped plasmid in terms of viral yield, albeit with a slight delay in virus recovery kinetics. RCA, however, has lower cost and time requirements and amplifies DNA with high fidelity and with no chance of unwanted mutations due to toxicity. We show that sequential RCA reactions do not introduce mutations into the viral genome and, thus, can replace the need for glycerol stocks or bacteria entirely. These results indicate that RCA is a viable alternative to traditional plasmid-based approaches to viral rescue.

Importance

The development of infectious cDNA clones is critical to studying viral pathogenesis and for developing vaccines. The current method for propagating clones in bacteria is limited by the toxicity of the viral genome within the bacterial host, resulting in deleterious mutations in the viral genome, which can only be detected through whole-genome sequencing. These mutations can attenuate the virus, leading to lost time and resources and potentially confounding results. We have developed an alternative method of preparing large quantities of DNA that can be directly transfected to recover infectious virus without the need for bacteria by amplifying the infectious cDNA clone plasmid using rolling circle amplification (RCA). Our results indicate that viral rescue from an RCA product produces a viral yield equal to bacterial-derived plasmid DNA, albeit with a slight delay in replication kinetics. The RCA platform, however, is significantly more cost and time-efficient compared to traditional approaches. When the simplicity and costs of RCA are combined, we propose that a shift to an RCA platform will benefit the field of molecular virology and could have significant advantages for recombinant vaccine production.
Identification and characterisation of a phospholipid scramblase in the malaria parasite Plasmodium falciparum
Authors: Haase Silvia , Condron Melanie , Miller David , Cherkaoui Dounia , Jordan Sarah , Gulbis Jacqueline M , Baum Jake
Published: June 2020

Recent studies highlight the emerging role of lipids as important messengers in malaria parasite biology. In an attempt to identify interacting proteins and regulators of these dynamic and versatile molecules, we hypothesised the involvement of phospholipid translocases and their substrates in the infection of the host erythrocyte by the malaria parasite Plasmodium spp. Here, using a data base mining approach, we have identified a putative phospholipid (PL) scramblase in P. falciparum (PfPLSCR) that is conserved across the genus and in closely related unicellular algae. By reconstituting recombinant PfPLSCR into liposomes, we demonstrate metal ion dependent PL translocase activity and substrate preference, confirming PfPLSCR as a bona fide scramblase. We confirm that PfPLSCR is expressed during asexual and sexual parasite development, localising to different membranous compartments of the parasite throughout the intra-erythrocytic life cycle. Two different gene knockout approaches, however, suggest that PfPLSCR is not essential for erythrocyte invasion and asexual parasite development, pointing towards a possible role in other stages of the parasite life cycle.
tacost: Testing and simulating the performance of acoustic tracking systems
Authors: Beleyur Thejasvi
Published: June 2020

tacostis a Python package to allow the testing of acoustic tracking systems. While many microphone array systems have been characterised analytically and experimentally – these are time-intensive methods.tacostprovides a simulation based framework to rapidly assess the tracking behaviour of multiple array geometries, and the dissection of other relevant parameters. This paper explains briefly the design of the package and highlights two example use cases in which the tracking accuracy of different microphone geometries are characterised.
Life-long telomere attrition predicts health and lifespan in a large mammal
Authors: Seeker Luise A. , Underwood Sarah L. , Wilbourn Rachael V. , Fairlie Jennifer , Froy Hannah , Holland Rebecca , Ilska Joanna J. , Psifidi Androniki , Bagnall Ainsley , Whitelaw Bruce , Coffey Mike , Banos Georgios , Nussey Daniel H.
Published: June 2020

Telomere length measured in blood cells is predictive of subsequent adult health and survival across a range of vertebrate species. However, we currently do not know whether such associations result from among-individual differences in telomere length determined genetically or by environmental factors early in life, or from differences in the rate of telomere attrition over the course of life. Here, we measured relative leukocyte telomere length (RLTL) multiple times across the entire lifespan of dairy cattle in a research population that is closely monitored for health and milk production and where individuals are only culled in response to health issues and less due to poor milk production than on purely commercial farms. Our results clearly show that the average amount of telomere attrition over an individual’s life, not their average or early life telomere length predicted when an individual was culled. Within-individual telomere length attrition could reflect environmental or physiological insults which may accumulate to predict individual health-span. We also show that animals with more telomere attrition in their first year of life were culled at a younger age, indicating that early life stressors may have a prolonged effect on adult life.
Stable integration of an optimized inducible promoter system enables spatiotemporal control of gene expression throughout avian development
Authors: Chu Daniel , Nguyen An , Smith Spenser S. , Vavrušová Zuzana , Schneider Richard A.
Published: June 2020

Precisely altering gene expression is critical for understanding molecular processes of embryogenesis. Although some tools exist for transgene misexpression in developing chick embryos, we have refined and advanced them by simplifying and optimizing constructs for spatiotemporal control. To maintain expression over the entire course of embryonic development we use an enhancedpiggyBactransposon system that efficiently integrates sequences into the host genome. We also incorporate a DNA targeting sequence to direct plasmid translocation into the nucleus and a D4Z4 insulator sequence to prevent epigenetic silencing. We designed these constructs to minimize their size and maximize cellular uptake, and to simplify usage by placing all of the integrating sequences on a single plasmid. Following electroporation of stage HH8.5 embryos, our tetracycline-inducible promoter construct produces robust transgene expression in the presence of doxycycline at any point during embryonic developmentin ovoor in culture. Moreover, expression levels can be modulated by titrating doxycycline concentrations and spatial control can be achieved using beads or gels. Thus, we have generated a novel, sensitive, tunable, and stable inducible-promoter system for high-resolution gene manipulationin vivo.
A link between inflammatory biomarkers and lung ultrasound observations in patients with SARS-CoV-2 infection
Authors: Wangüemert Pérez Aurelio Luis , Figueira Gonçalves Juan Marco , Hernández Pérez José María , Ramallo- Fariña Yolanda , del Castillo Rodríguez José Carlos
Published: June 2020

Lung ultrasound (LUS) has shown to correlate well with the findings obtained by chest computed tomography (CT) in acute-phase COVID-19. Although there is a significant correlation between blood biomarkers and CT radiological findings, a potential correlation between biochemical parameters and LUS images is still unknown. Our purpose was to evaluate a potential association between lung lesions visualised by LUS and blood biomarkers as well as the ability to predict mortality from two different lung ultrasound scoring systems (LUSS). We performed a retrospective observational study on 45 patients aged >70 years with SARS-CoV-2 infection who required hospitalisation. LUS was carried out at admission and on day 7, when the clinical course was favourable or earlier in case of worsening. Disease severity was scored by means of LUSS in 8 (LUSS8) and in 12 (LUSS12) quadrants. LUS and blood draw for inflammatory marker analysis were performed at the same time. The correlation between biochemical parameters and either LUSS score was significant for ferritin levels. It was 0.486 (p=0.001) for LUSS8 and 0.458 (p=0.002) for LUSS12. Using a threshold score of 15 with LUSS12 predicted mortality in 86.7% of cases (ORcrude 31, CI 95% 4.79–200.51). Applying a threshold of 10 with LUSS8 predicted mortality in 88.9% (ORcrude 69.75, CI 95% 6.90–705.20). There is a correlation between ferritin levels and LUSS. The prognostic capacity of LUSS12 does not surpass that of LUSS8.

“Take-home message”

There is a correlation between lung ultrasound scoring results and serum ferritin levels in patients with SARS-CoV-2 infection.
Brain Impairment revealed by Multi-Modality MRI in Parkinson’s Disease
Authors: Ran Zhang , Ping Gong , Haitao Ge
Published: June 2020

Objective

To study the abnormal brain regions of patients with Parkinson’s disease (PD) using multimodality MRI to provide complementary information for early detection for PD.

Methods

27 patients with early PD and 25 normal ageing volunteers were included in the study. Multimodality MRI data were acquired and processed to extract neuroimaging features to test the structural and functional changes using a two-sample t-test.

Results

The changes of brain regions were disagreed for different modality MRI data between PD and normal ageing individuals. Nevertheless,the postcentral gyrus, precentral gyrus, lingual gyrus and paracentral lobule were significantly different for all three modalities.

Conclusion

Multimodality MRI data can reflect the structural and functional changes of PD, and reveal the hidden information which is of great significance to assist early detection for PD.
First results from the UK COVID-19 Serology in Oncology Staff Study (CSOS)
Authors: Favara DM , Cooke A , Doffinger R , Houghton S , Budriunaite I , Bossingham S , McAdam K , Corrie P , Ainsworth N
Published: June 2020

Background

The global SARS-CoV-2 (COVID-19) pandemic has caused substantial worldwide mortality. At present, there is no data regarding oncologist-specific SARS-CoV-2 infection/immunity rates in the United Kingdom (UK) which might impact planning for the management of potentially immunosuppressed cancer patients. Here, we present the first results from the COVID-19 Serology in Oncology Staff (CSOS) study with the aim of informing non-surgical oncology management guidelines.

Methods

Patient-facing staff working in an oncology department during the COVID-19 pandemic at a large district general hospital in the East of England were invited to participate. Samples were collected during the first week of June 2020: blood for SARS-COV-2 antibody testing using a rapid lateral flow point of care (POC) assay and a laboratory Luminex based assay, as well as a nasopharyngeal swab for SARS-CoV-2 PCR testing. Participant characteristics were also collected.

Results

Seventy participants were recruited: nurses (45/70; 64.3%), doctors (15/70; 21.2%), and other patient-facing staff (10/70; 14.3%). The majority were female (61/70; 87.1%) with a mean age of 42 years (median 41; range 23-64 years). A minority were smokers (9/70; 10%) or had chronic underlying health conditions (16/70; 22.9%), the commonest being asthma. All participants were nasopharyngeal-swab PCR negative, although 4/70 (5.7%) had previously tested positive by NHS testing undertaken during the preceding months. 15/70 (21.4%) had positive SARS-CoV-2 antibodies using the Luminex test. Nurses had the highest incidence of positive antibodies (13/45; 28.9%), with a lower incidence in doctors (2/15; 13.3%) although this difference was not statistically significant (Fischer’s exact test p=0.3). No receptionists had positive antibody tests. All four participants with a previously reported positive PCR test were antibody-positive. 9/15 (60%) of antibody-positive participants reported previous symptoms suggestive of SARS-CoV-2 infection: a 3.6-fold higher odds than antibody-negative participants, of whom 16/55 reported symptoms (p=0.03). The mean duration of symptoms was 11 days (median 11; range 1-35 days) and the mean time from resolution of reported previous symptoms to antibody testing was 48.4 days (median 46; range 1-123 days).

Conclusion

This study establishes the SARS-CoV-2 exposure and carriage rate amongst patient-facing staff working in the oncology department of a large UK general hospital during the pandemic. These results may help inform UK national oncology patient management prior to the development of a viable vaccine or treatment.
Effect of Dexamethasone in Hospitalized Patients with COVID-19 – Preliminary Report
Authors: Horby Peter , Lim Wei Shen , Emberson Jonathan , Mafham Marion , Bell Jennifer , Linsell Louise , Staplin Natalie , Brightling Christopher , Ustianowski Andrew , Elmahi Einas , Prudon Benjamin , Green Christopher , Felton Timothy , Chadwick David , Rege Kanchan , Fegan Christopher , Chappell Lucy C , Faust Saul N , Jaki Thomas , Jeffery Katie , Montgomery Alan , Rowan Kathryn , Juszczak Edmund , Baillie J Kenneth , Haynes Richard , Landray Martin J ,   RECOVERY Collaborative Group
Published: June 2020

Background

Coronavirus disease 2019 (COVID-19) is associated with diffuse lung damage. Corticosteroids may modulate immune-mediated lung injury and reducing progression to respiratory failure and death.

Methods

The Randomised Evaluation of COVID-19 therapy (RECOVERY) trial is a randomized, controlled, open-label, adaptive, platform trial comparing a range of possible treatments with usual care in patients hospitalized with COVID-19. We report the preliminary results for the comparison of dexamethasone 6 mg given once daily for up to ten days vs. usual care alone. The primary outcome was 28-day mortality.

Results

2104 patients randomly allocated to receive dexamethasone were compared with 4321 patients concurrently allocated to usual care. Overall, 454 (21.6%) patients allocated dexamethasone and 1065 (24.6%) patients allocated usual care died within 28 days (age-adjusted rate ratio [RR] 0.83; 95% confidence interval [CI] 0.74 to 0.92; P<0.001). The proportional and absolute mortality rate reductions varied significantly depending on level of respiratory support at randomization (test for trend p<0.001): Dexamethasone reduced deaths by one-third in patients receiving invasive mechanical ventilation (29.0% vs. 40.7%, RR 0.65 [95% CI 0.51 to 0.82]; p<0.001), by one-fifth in patients receiving oxygen without invasive mechanical ventilation (21.5% vs. 25.0%, RR 0.80 [95% CI 0.70 to 0.92]; p=0.002), but did not reduce mortality in patients not receiving respiratory support at randomization (17.0% vs. 13.2%, RR 1.22 [95% CI 0.93 to 1.61]; p=0.14).

Conclusions

In patients hospitalized with COVID-19, dexamethasone reduced 28-day mortality among those receiving invasive mechanical ventilation or oxygen at randomization, but not among patients not receiving respiratory support.

Trial registrations

The RECOVERY trial is registered with ISRCTN (50189673) and clinicaltrials.gov (NCT04381936).

Funding

Medical Research Council and National Institute for Health Research (Grant ref: MC_PC_19056).
Vitamin D insufficiency and deficiency and mortality from respiratory diseases in a cohort of older adults: potential for limiting the death toll during and beyond the COVID-19 pandemic
Authors: Brenner Hermann , Holleczek Bernd , Schöttker Ben
Published: June 2020

Background

The COVID-19 pandemic goes along with increased mortality from acute respiratory disease, and measures to limit the spread of the infection go along with increased risk of vitamin D deficiency, especially among high risk groups. It has been suggested that vitamin D3 supplementation might help to reduce respiratory disease mortality.

Methods

We assessed the prevalence of vitamin D insufficiency and deficiency, defined by 25(OH)D blood levels of 30-50 and <30 nmol/L, respectively, and their association with mortality from respiratory diseases during 15 years of follow-up in a cohort of 9,548 adults aged 50-75 years from Saarland, Germany.

Results

Vitamin D insufficiency and deficiency were common (44% and 15%, respectively). Compared to sufficient vitamin D status, respiratory disease mortality was 2.1 (95%-CI 1.3-3.2)- and 3.0 (95%-CI 1.8-5.2)-fold increased, respectively. Although significant increases were seen in both women and men, they were much stronger among women, with 8.5 (95% CI 2.4-30.1) and 2.3 (95% CI 1.1-4.4)-fold increase of respiratory disease mortality in case of vitamin D deficiency among women and men, respectively (p-value for interaction =0.041). Overall, 41% (95% CI 20%-58%) of respiratory disease mortality was statistically attributable to vitamin D insufficiency or deficiency.

Conclusion

Vitamin D insufficiency and deficiency are common and account for a large proportion of respiratory disease mortality in older adults, supporting suggestions that vitamin D3 supplementation might make a major contribution to limit the burden of the COVID-19 pandemic, particularly among women.
A juxtaposition of safety outcomes between various doses of sodium-glucose co-transporter inhibitors, in insulin-treated type-1 diabetes mellitus patients: a protocol for systematic review and meta-analysis of double-blinded randomized controlled trials
Authors: Saha Sumanta
Published: June 2020

Aims

Several clinical trials have tested the safety profile of sodium-glucose co-transport inhibitors’ (SGLTis) in adult type 1 diabetes mellitus (T1DM) patients. However, no systematic review has compared its variation between large and low dose SGLTis. Henceforth, a review protocol is proposed here to review it. Besides, it will compare the side effects of each of these interventions with the placebo.

Methods

Different electronic databases will be searched for randomized double-blinded placebo-controlled trials (published in the English language) studying the above objective, irrespective of their publication date. After selecting the eligible trials, their data on the study design, population characteristics, compared interventions, and outcomes of interest will be extracted. Then, utilizing the Cochrane tool, each trial’s risk of selection bias, detection bias, performance bias, attrition bias, reporting bias, and other bias will be judged. Next, depending on clinical heterogeneity among the trials, a random-effect or fixed-effect model meta-analysis will be used to compare the respective outcomes. Via the Chi2 and I2 statistics, the statistical inconsistency among the trials will be estimated. When this is substantial, subgroup analysis will follow. Publication bias will be evaluated by funnel plots and Egger’s test. A sensitivity analysis will be done to check different assumptions. If a quantitative juxtaposition is not possible, a narrative reporting will ensue. Conclusions: The proposed review will compare the safety profile between the mega and low dose SGLTis in insulin-treated T1DM patients. Besides, each of these two types of doses will be compared with placebo for the same.

REGISTRATION

PROSPERO (Registration no. CRD42019146578)
The timing and effectiveness of implementing mild interventions of COVID-19 in large industrial regions via a synthetic control method
Authors: Tian Ting , Luo Wenxiang , Tan Jianbin , Jiang Yukang , Chen Minqiong , Pan Wenliang , Yang Songpan , Zhao Jiashu , Wang Xueqin , Zhang Heping
Published: June 2020

The outbreak of novel coronavirus disease (COVID-19) has spread around the world since it was detected in December 2019. The Chinese government executed a series of interventions to curb the pandemic. The “battle” against COVID-19 in Shenzhen, China is valuable because populated industrial cities are the epic centres of COVID-19 in many regions. We made use of synthetic control methods to create a reference population matching specific characteristics of Shenzhen. With both the synthetic and observed data, we introduced an epidemic compartmental model to compare the spread of COVID-19 between Shenzhen and its counterpart regions in the United States that didn’t implement interventions for policy evaluation. Once the effects of policy interventions adopted in Shenzhen were estimated, the delay effects of those interventions were referred to provide the further control degree of interventions. Thus, the hypothetical epidemic situations in Shenzhen were inferred by using time-varying reproduction numbers in the proposed SIHR (Susceptible, Infectious, Hospitalized, Removed) model and considering if the interventions were delayed by 0 day to 5 days. The expected cumulative confirmed cases would be 1546, which is 5.75 times of the observed cumulative confirmed cases of 269 in Shenzhen on February 3, 2020, based on the data from the counterpart counties (mainly from Broward, New York, Santa Clara, Pinellas, and Westchester) in the United States. If the interventions were delayed by 5 days from the day when the interventions started, the expected cumulative confirmed cases of COVID-19 in Shenzhen on February 3, 2020 would be 676 with 95% credible interval (303,1959). Early implementation of mild interventions can subdue the epidemic of COVID-19. The later the interventions were implemented, the more severe the epidemic was in the hard-hit areas. Mild interventions are less damaging to the society but can be effective when implemented early.

AMS 2000 subject classifications: Primary 00K00, 00K01; secondary 00K02.
The impact of asymptomatic COVID-19 infections on future pandemic waves
Authors: Fox Spencer J , Pasco Remy , Tec Mauricio , Du Zhanwei , Lachmann Michael , Scott James , Meyers Lauren Ancel
Published: June 2020

Letter text

The prevalence of asymptomatic COVID-19 infections is largely unknown and may determine the course of future pandemic waves and the effectiveness of interventions. Using an epidemiological model fit to COVID-19 hospitalization counts from New York City, New York and Austin, Texas, we found that theundocumentedattack rate in the first pandemic wave depends on the proportion of asymptomatic infections but not on the infectiousness of such individuals. Based on a recent report that 22.7% of New Yorkers are seropositive for SARS-CoV-2, we estimate that 56% (95% CI: 53-59%) of COVID-19 infections are asymptomatic. Given uncertainty in the case hospitalization rate, however, the asymptomatic proportion could be as low as 20% or as high as 80%. We find that at most 1.26% of the Austin population was infected by April 27, 2020 and conclude that immunity from undetected infections is unlikely to slow future pandemic spread in most US cities in the summer of 2020.
The impact of COVID-19 non-pharmaceutical interventions on the future dynamics of endemic infections
Authors: Baker Rachel E. , Park Sang Woo , Yang Wenchang , Vecchi Gabriel A. , Metcalf C. Jessica E. , Grenfell Bryan T.
Published: June 2020

Non-pharmaceutical interventions (NPIs) have been employed to reduce the transmission of SARS-CoV-2, yet these measures are already having similar effects on other directly-transmitted, endemic diseases. Disruptions to the seasonal transmission patterns of these diseases may have consequences for the timing and severity of future outbreaks. Here we consider the implications of SARS-CoV-2 NPIs for two endemic infections circulating in the United States of America (USA): respiratory syncytial virus (RSV) and seasonal influenza. Using laboratory surveillance data from 2020, we estimate that RSV transmission declined by at least 20% in the USA at the start of the NPI period. We simulate future trajectories of both RSV and influenza, using an epidemic model. As susceptibility increases over the NPI period, we find that substantial outbreaks of RSV may occur in future years, with peak outbreaks likely occurring in the winter of 2021-2022. Results for influenza broadly echo this picture, but are more uncertain; future outbreaks are likely dependent on the transmissibility and evolutionary dynamics of circulating strains.
Universal scaling law for COVID-19 propagation in urban centers
Authors: Cardoso Ben-Hur Francisco , Gonçalves Sebastián
Published: June 2020

Due to the COVID-19 pandemic, there is a high demand for Susceptible-Infective-Recovered (SIR) models to adjust and predict the number of cases in urban areas. Forecasting, however, is a difficult task, because the change in people’s behavior reflects in a continuous change in the parameters of the model. An important question is what we can use from one city to another; if what happened in Madrid could have been applied to New York and then, if what we have learned from this city would be useful for São Paulo. To answer this question, we present an analysis of the transmission rate of COVID-19 as a function of population density and population size for US counties, cities of Brazil, German, and Portugal. Contrary to the common hypothesis in epidemics modeling, we observe a higher disease transmissibility for higher city’s population density/size –with the latter showing more predicting power. We present a contact rate scaling theory that explain the results, predicting that the basic reproductive numberR0of epidemics scales as the logarithm of the city size.
Closed-loop control of k-space sampling via physiologic feedback for cine MRI
Authors: Contijoch Francisco , Han Yuchi , Iyer Srikant Kamesh , Kellman Peter , Gualtieri Gene , Elliott Mark A. , Berisha Sebastian , Gorman Joseph H. , Gorman Robert C. , Pilla James J. , Witschey Walter R.
Published: June 2020

Background

Segmented cine cardiac MRI combines data from multiple heartbeats to achieve high spatiotemporal resolution cardiac images, yet predefined k-space segmentation trajectories can lead to suboptimal k-space sampling. In this work, we developed and evaluated an autonomous and closed-loop control system for radial k-space sampling to increase sampling uniformity.

Methods

The closed-loop system autonomously selects radial k-space sampling trajectory during live segmented cine MRI and attempts to optimize angular sampling uniformity by selecting views in regions of k-space that were not previously well-sampled. Sampling uniformity and robustness to arrhythmias was assessed using ECG data acquired from 10 normal subjects in an MRI scanner. The approach was then implemented with a fast gradient echo sequence on a whole-body clinical MRI scanner and imaging was performed in 4 healthy volunteers. The closed-loop k-space trajectory was compared to random, uniformly distributed and golden angle view trajectories via measurement of k-space uniformity and the point spread function. Lastly, an arrhythmic dataset was used to evaluate a potential application of the approach.

Results

The autonomous trajectory increased k-space sampling uniformity by 13±7%, main lobe point spread function (PSF) signal intensity by 14±6%, and reduced ringing relative to golden angle sampling. When implemented, the autonomous pulse sequence prescribed radial view angles faster than the scan TR (0.98 ± 0.02 ms, maximum = 1.38 ms) and increased k-space sampling mean uniformity by 5±12%, decreased uniformity variability by 45±14%, and increased PSF signal ratio by 5±5% relative to golden angle sampling.

Conclusion

The closed-loop approach enables near-uniform radial sampling in a segmented acquisition approach which was higher than predetermined golden-angle radial sampling. This can be utilized to increase the sampling or decrease the temporal footprint of an acquisition and the closed-loop framework has the potential to be applied to patients with complex heart rhythms.
SARS-CoV-2 exposure, symptoms and seroprevalence in health care workers
Authors: Rudberg Ann-Sofie , Havervall Sebastian , Månberg Anna , Falk August Jernbom , Aguilera Katherina , Ng Henry , Gabrielsson Lena , Salomonsson Ann-Christine , Hanke Leo , Murrell Benjamin , McInerney Gerald , Olofsson Jennie , Andersson Eni , Hellström Cecilia , Bayati Shaghayegh , Bergström Sofia , Pin Elisa , Sjöberg Ronald , Tegel Hanna , Hedhammar My , Phillipson Mia , Nilsson Peter , Hober Sophia , Thålin Charlotte
Published: June 2020

Background

SARS-CoV-2 may pose an occupational health risk to health care workers, but the prevalence of infections in this population is unknown. We examined the seroprevalence of SARS-CoV-2 antibodies among health care workers at a large acute care hospital in Stockholm, Sweden. We determined correlations between seroprevalence, self-reported symptoms and occupational exposure to SARS-CoV-2.

Methods and findings

All employees at Danderyd Hospital (n=4375) were invited to participate in a cross-sectional study. 2149 employees from all hospital departments were enrolled in the study between April 14th and May 8th 2020. Study participants completed a questionnaire consisting of symptoms compatible with SARS-CoV-2 infection since January 2020 and occupational exposure to patients infected with SARS-CoV-2. IgG antibodies against SARS-CoV-2 were analyzed using a multiplex assay evaluated to have 99.4% sensitivity and 99.1% specificity. The over-all seroprevalence among 2149 participants was 19.1% (n=410). There was no difference in age or sex between seropositive and seronegative participants. The symptoms with the strongest correlation to seroprevalence were anosmia and ageusia, with odds ratios of 28.4 (p=2.02*10^-120) and 19.2 (p=1.67*10^-99) respectively. Seroprevalence was strongly associated with patient-related work (OR 2.9, p=4.24*10^-8), covid-19 patient contact (OR 1.43, p=0.003), and occupation as assisting nurse (OR 3.67, p=2.16*10^-9).

Conclusion

These results demonstrate that anosmia and ageusia should be included in screening guidance and in the recommendations of self-isolation to reduce further spread of SARS-CoV-2. The results furthermore imply an occupational health risk for SARS-CoV-2 infection among hospital workers. Continued measures are warranted to assure healthcare worker safety and reduce transmission from health care settings to the community during the covid-19 outbreak.
Age-structured non-pharmaceutical interventions for optimal control of COVID-19 epidemic
Authors: Richard Quentin , Alizon Samuel , Choisy Marc , Sofonea Mircea T. , Djidjou-Demasse Ramsès
Published: June 2020

In an epidemic, individuals can widely differ in the way they spread the infection, for instance depending on their age or on the number of days they have been infected for. The latter allows to take into account the variation of infectiousness as a function of time since infection. In the absence of pharmaceutical interventions such as a vaccine or treatment, non-pharmaceutical interventions (e.g. social distancing) are of great importance to mitigate the pandemic. We propose a model with a double continuous structure by host age and time since infection. By applying optimal control theory to our age-structured model, we identify a solution minimizing deaths and costs associated with the implementation of the control strategy itself. This strategy depends on the age heterogeneity between individuals and consists in a relatively high isolation intensity over the older populations during a hundred days, followed by a steady decrease in a way that depends on the cost associated to a such control. The isolation of the younger population is weaker and occurs only if the cost associated with the control is relatively low. We show that the optimal control strategy strongly outperforms other strategies such as uniform constant control over the whole populations or over its younger fraction. These results bring new facts the debate about age-based control interventions and open promising avenues of research, for instance of age-based contact tracing.
National Health Insurance Scheme: A pathway to a sustained access to medicine in Nigeria
Authors: Uguru Nkoli P. , Ogu Udochukwu U. , Uguru Chibuzo C. , Ibe Ogochukwu
Published: June 2020

Objective

The National Health Insurance Scheme (NHIS) has at its aim the need to ensure that every Nigerian has equal access to good quality health care services. So far, only the Formal Sector Social Health Insurance Program (FSSHIP) aspect of the scheme has been fully activated. The question remains, why the delay towards universal coverage?

Design

The study was a cross-sectional and mixed method design. Both qualitative and quantitative methods were utilized for the study.

Setting

This study was conducted in NHIS accredited facilities in Enugu State.

Participants

A sample of 300 enrolees were selected randomly. For the qualitative study, 6 in-depth interviews (IDIs) were conducted face to face with NHIS desk officers across the three tiers of health care represented.

Results

The qualitative findings shows that 94.9% of respondents sought medical help. 78.4% of the respondents indicated that the scheme improved their access to care. The qualitative finding found that there was no discrepancy in access among socio-economic groups. NHIS was reported to have improved access to medicine over the years. In the qualitative, majority of the IDI respondents stated that many of the staff in NHIS accredited facilities are not trained on what is expected or required of them with regards to the scheme.

Conclusion

A focus on accessibility, affordability and availability for the scheme means that on account of either of the three, all facility categories and their interests must be considered in further planning of the scheme to ensure that things hold up fine.

Article Summary

Strengths and Limitations

The study participants were only from one state.

The study only focused on NHIS and NHIS accredited facilities.

NHIS desk officers, hospital directors and admin officers were the focus for IDIs.
The Tomato DELLA Protein PROCERA Promotes Abscisic Acid Responses in Guard Cells by Upregulating an Abscisic Acid Transporter
Authors: Shohat Hagai , Illouz-Eliaz Natanella , Kanno Yuri , Seo Mitsunori , Weiss David
Published: June 2020

Plants reduce transpiration through stomatal closure to avoid drought stress. While abscisic acid (ABA) has a central role in the regulation of stomatal closure under water-deficit conditions, we demonstrated in tomato (Solanum lycopersicum) that a gibberellin response inhibitor, the DELLA protein PROCERA (PRO), promotes ABA-induced stomatal closure and gene transcription in guard cells. To study how PRO affects stomatal closure, we performed RNA-sequencing analysis of isolated guard cells and identified the ABA transporters ABA-IMPORTING TRANSPORTER1.1 (AIT1.1) and AIT1.2, also called NITRATE TRANSPORTER1/PTR TRANSPORTER FAMILY4.6 in Arabidopsis (Arabidopsis thaliana), as being upregulated by PRO. Tomato has four AIT1 genes, but only AIT1.1 and AIT1.2 were upregulated by PRO, and only AIT1.1 exhibited high expression in guard cells. Functional analysis of AIT1.1 in yeast (Saccharomyces cerevisiae) confirmed its activity as an ABA transporter, possibly an importer. A clustered regularly interspaced short palindromic repeats-Cas9–derived ait1.1 mutant exhibited an increased transpiration, a larger stomatal aperture, and a reduced stomatal response to ABA. Moreover, ait1.1 suppressed the promoting effects of PRO on ABA-induced stomatal closure and gene expression in guard cells, suggesting that the effects of PRO on stomatal aperture and transpiration are AIT1.1-dependent. Previous studies suggest a negative crosstalk between gibberellin and ABA that is mediated by changes in hormone biosynthesis and signaling. The results of this study suggest this crosstalk is also mediated by changes in hormone transport.
Polymorphism of bis(1,3-benzothiazol-2-yl) trithiocarbonate
Authors: Kafuta Kevin , Golz Christopher , Alcarazo Manuel
Published: June 2020

The polymorphism of the title compound, C15H8N2S5, is reported, in which the (syn,syn) and (syn,anti) conformers simultaneously crystallized from a chloroform solution. The complete molecule of the (syn,syn) form is generated by a crystallographic twofold axis. The geometries of both conformers are compared in detail, revealing no significant differences in bond lengths, despite different bond angles because of the conformational changes. Analysis of the intermolecular interactions, aided by Hirshfeld surfaces, shows distinctive S...S and S...N contacts only for the (syn,anti) conformer. Aromatic π–π-stacking interactions are found for both conformers, which occur for the (syn,anti) conformer between pairs of molecules, but are continuous stacks in the (syn,syn) conformer. Non merohedral twinning was found for the crystal of the (syn,anti) conformer used for data collection.
Repatriation of self-initiated expatriates: expectations vs. experiences
Authors: Ellis David R. , Thorn Kaye , Yao Christian
Published: June 2020

Purpose

While there is a burgeoning literature on self-initiated expatriates (SIEs), the emphasis has been on expatriation not repatriation. The purpose of this paper therefore is to explore how repatriating SIEs perceive the experience of repatriation compared with their pre-repatriation expectations. Further, we examine the seminal work of Black et al. (1992) in the light of current day realities.

Design/methodology/approach

This qualitative research draws on interviews with SIE New Zealanders returning home. It is an exploratory longitudinal study, based on interview data collected prior to (n = 32), and after (n = 27) repatriation, comparing expectations and experiences of repatriation.

Findings

Findings show that there is a strong level of congruence between the expectations of the return and their experience of repatriation. This congruence eases the transition and mitigates the impact of reverse culture shock. We revise Black et al.'s framework of repatriation adjustment to more accurately reflect the expectations and experiences of repatriating SIEs, recognising the importance of individual agency and the impact of today's technological advances on repatriation.

Research limitations/implications

The contributions of this paper include clarification of repatriating SIEs. Further, through the revision of the framework, we identify new areas of research that would aid our understanding of repatriating SIEs and lead to the development of a more detailed model. We highlight the interplay between variables showing how these might mitigate the shock of repatriation.

Originality/value

Repatriation is an under-researched phase of the SIE, and this study provides empirical data that contributes to our understanding of the construct. Black et al.'s framework of repatriation adjustment is revised in the context of contemporary SIE, highlighting the holistic nature of self-initiated expatriation and repatriation, viewing the events not as discrete, but as a continuum of time.
Analytical solution of the Duffing equation
Authors: Georgiev Zhivko , Trushev Ivan , Todorov Todor , Uzunov Ivan
Published: June 2020

Purpose

The purpose of this paper is to find an exact analytical expression for the periodic solutions of the double-hump Duffing equation and an expression for the period of these solutions.

Design/methodology/approach

The double-hump Duffing equation is presented as a Hamiltonian system and a phase portrait of this system has been found. On the ground of analytical calculations performed using Hamiltonian-based technique, the periodic solutions of this system are represented by Jacobi elliptic functions sn, cn and dn.

Findings

Expressions for the periodic solutions and their periods of the double-hump Duffing equation have been found. An expression for the solution, in the time domain, corresponding to the heteroclinic trajectory has also been found. An important element in various applications is the relationship obtained between constant Hamiltonian levels and the elliptic modulus of the elliptic functions.

Originality/value

The results obtained in this paper represent a generalization and improvement of the existing ones. They can find various applications, such as analysis of limit cycles in perturbed Duffing equation, analysis of damped and forced Duffing equation, analysis of nonlinear resonance and analysis of coupled Duffing equations.
Energy-efficient data retention in D flip-flops using STT-MTJ
Authors: Monga Kanika , Chaturvedi Nitin , Gurunarayanan S.
Published: June 2020

Purpose

Emerging event-driven applications such as the internet-of-things requires an ultra-low power operation to prolong battery life. Shutting down non-functional block during standby mode is an efficient way to save power. However, it results in a loss of system state, and a considerable amount of energy is required to restore the system state. Conventional state retentive flip-flops have an “Always ON” circuitry, which results in large leakage power consumption, especially during long standby periods. Therefore, this paper aims to explore the emerging non-volatile memory element spin transfer torque-magnetic tunnel junction (STT-MTJ) as one the prospective candidate to obtain a low-power solution to state retention.

Design/methodology/approach

The conventional D flip-flop is modified by using STT-MTJ to incorporate non-volatility in slave latch. Two novel designs are proposed in this paper, which can store the data of a flip-flip into the MTJs before power off and restores after power on to resume the operation from pre-standby state.

Findings

A comparison of the proposed design with the conventional state retentive flip-flop shows 100 per cent reduction in leakage power during standby mode with 66-69 per cent active power and 55-64 per cent delay overhead. Also, a comparison with existing MTJ-based non-volatile flip-flop shows a reduction in energy consumption and area overhead. Furthermore, use of a fully depleted-silicon on insulator and fin field-effect transistor substituting a complementary metal oxide semiconductor results in 70-80 per cent reduction in the total power consumption.

Originality/value

Two novel state-retentive D flip-flops using STT-MTJ are proposed in this paper, which aims to obtain zero leakage power during standby mode.
Predictors of health behaviours among Indian college students: an exploratory study
Authors: Chawak Shweta , Chittem Mahati , S Aswini , Varghese Daigy , Epton Tracy
Published: June 2020

Purpose

The purpose of this study is to understand the association between health behaviours of diet, physical activity, smoking cigarettes, alcohol consumption, safe sex and sleep quality with demographic (e.g. age, gender) and psychological (i.e. stress, self-esteem and sense of coherence) factors in Indian residential college students.

Design/methodology/approach

Students studying for Bachelor of Technology at residential colleges in India were invited to complete an online questionnaire regarding their health behaviours, demographics and psychological variables. Each health behaviour was regressed onto demographic and psychological factors to determine which of them were associated with performing each behaviour.

Findings

There was no clear pattern of predictors for the health behaviours overall. Self-esteem was related to healthy diet, being single was related to adequate sleep, higher parental income was related to safer sex and being older was related to more alcohol use and safer sex.

Research limitations/implications

This study revealed that health education efforts may need to be designed for specific behaviours and correlates among Indian college students. Interventions regarding (1) healthy eating should target students with lower self-esteem, (2) sleep should target students in a relationship and (3) safer sex should target younger students and those from less affluent backgrounds.

Originality/value

This research is one of the first attempts to study the predictors of health behaviours among Indian college students. The study highlighted that psychological factors (e.g. self-esteem) and demographic factors (e.g. relationship status, parental income, age) affect different health behaviours. These findings can help health educators to design tailored interventions and aid in health education and promotion among Indian college students.