bluuebunny/crossref_metadata_2025 huggingface dataset:
In invasion assays, the breast cancer cell nucleus leads the way
Authors: Renz Malte
Published: October 2020

Objective

Cancer cell metastasis determines disease prognosis. During cancer cell metastasis, the cancer cell and the cancer cell nucleus have to undergo extreme shape changes. To monitor shape changes of cancer cells and cancer cell nuclei and the positioning of the cancer cell nucleus during cancer cell invasion, a customized invasion assay with 8-μm pores and reconstituted basal membrane was imaged using fluorescence live-cell microscopy.

Results

The observed cells changed their shape from a distinct fibroblast-like spindle shape to an amoeboid shape without polarization immediately after the passage through an 8-μm pore of the invasion assay. During the process of invasion, the cancer cell centered the cancer cell nucleus over the 8-μm pore, and cancer cell nucleus and adjacent cytoplasmic areas moved first through such a pore. Seemingly testing if the largest and least deformable organelle may fit, the cancer cell nucleus led the way through the porous membrane of the invasion assay.
New perspectives of purple starthistle (Centaurea calcitrapa) leaf extracts: phytochemical analysis, cytotoxicity and antimicrobial activity
Authors: Dimkić Ivica , Petrović Marija , Gavrilović Milan , Gašić Uroš , Ristivojević Petar , Stanković Slaviša , Janaćković Peđa
Published: October 2020

Ethnobotanical and ethnopharmacological studies of many Centaurea species indicated their potential in folk medicine so far. However, investigations of different Centaurea calcitrapa L. extracts in terms of cytotoxicity and antimicrobial activity against phytopathogens are generally scarce. The phenolic profile and broad antimicrobial activity (especially towards bacterial phytopathogens) of methanol (MeOH), 70% ethanol (EtOH), ethyl-acetate (EtOAc), 50% acetone (Me2CO) and dichloromethane: methanol (DCM: MeOH, 1: 1) extracts of C. calcitrapa leaves and their potential toxicity on MRC-5 cell line were investigated for the first time. A total of 55 phenolic compounds were identified: 30 phenolic acids and their derivatives, 25 flavonoid glycosides and aglycones. This is also the first report of the presence of centaureidin, jaceidin, kaempferide, nepetin, flavonoid glycosides, phenolic acids and their esters in C. calcitrapa extracts. The best results were obtained with EtOAc extract with lowest MIC values expressed in µg/mL ranging from 13 to 25, while methicillin resistant Staphylococcus aureus was the most susceptible strain. The most susceptible phytopathogens were Pseudomonas syringae pv. syringae, Xanthomonas campestris pv. campestris and Agrobacterium tumefaciens. The highest cytotoxicity was recorded for EtOAc and Me2CO extracts with the lowest relative and absolute IC50 values between 88 and 102 µg/mL, while EtOH extract was the least toxic with predicted relative IC50 value of 1578 µg/mL. Our results indicate that all tested extracts at concentration considered as non-toxic can be one of great importance in combat towards phytopathogenic and human pathogenic strains, as well as natural sources of antimicrobials.
Echo simulation of dual polarization Doppler weather radar based on the physical model
Authors: JieLa Qutie , Wang Haijiang , Hu Shipeng , Zhu Jiahui , Gao Mengqing
Published: October 2020

Using the scattering characteristics of particles to simulate the radar echo can supply the test signals close to the real precipitation echo for the weather radar and save the time and cost of the research and development and maintenance of the weather radar. In this paper, the precipitation echo of weather radar is simulated based on the theoretical basis that the falling raindrops have a shape well approximated by an oblate spheroid in the atmosphere. The Marshal-Palmer distribution is applied to describe the raindrop spectrum distribution of precipitation particles. It is assumed that the raindrop particles of different sizes have the random distribution in the radar resolution volume, and then the spatial distribution of precipitation particles in the resolution volume is modeled. The echo signals of horizontal and vertical polarization channels of dual-polarization weather radar are obtained by vector superposition of backscattering echoes of each particle. The experimental results show that this method can describe the microphysical characteristics of precipitation particles more completely and can be used to test the signal processing module of dual-polarization Doppler weather radar.
Development of a quantitative segmentation model to assess the effect of comorbidity on patients with COVID-19
Authors: Zhang Cui , Yang Guangzhao , Cai Chunxian , Xu Zhihua , Wu Hai , Guo Youmin , Xie Zongyu , Shi Hengfeng , Cheng Guohua , Wang Jian
Published: October 2020

Background

The coronavirus disease 2019 (COVID-19) has brought a global disaster. Quantitative lesions may provide the radiological evidence of the severity of pneumonia and further to assess the effect of comorbidity on patients with COVID-19.

Methods

294 patients with COVID-19 were enrolled from February, 24, 2020 to June, 1, 2020 from six centers. Multi-task Unet network was used to segment the whole lung and lesions from chest CT images. This deep learning method was pre-trained in 650 CT images (550 in primary dataset and 100 in test dataset) with COVID-19 or community-acquired pneumonia and Dice coefficients in test dataset were calculated. 50 CT scans of 50 patients (15 with comorbidity and 35 without comorbidity) were random selected to mark lesions manually. The results will be compared with the automatic segmentation model. Eight quantitative parameters were calculated based on the segmentation results to evaluate the effect of comorbidity on patients with COVID-19.

Results

Quantitative segmentation model was proved to be effective and accurate with all Dice coefficients more than 0.85 and all accuracies more than 0.95. Of the 294 patients, 52 (17.7%) patients were reported having at least one comorbidity; 14 (4.8%) having more than one comorbidity. Patients with any comorbidity were older (P < 0.001), had longer incubation period (P < 0.001), were more likely to have abnormal laboratory findings (P < 0.05), and be in severity status (P < 0.001). More lesions (including larger volume of lesion, consolidation, and ground-glass opacity) were shown in patients with any comorbidity than patients without comorbidity (all P < 0.001). More lesions were found on CT images in patients with more comorbidities. The median volumes of lesion, consolidation, and ground-glass opacity in diabetes mellitus group were largest among the groups with single comorbidity that had the incidence rate of top three.

Conclusions

Multi-task Unet network can make quantitative CT analysis of lesions to assess the effect of comorbidity on patients with COVID-19, further to provide the radiological evidence of the severity of pneumonia. More lesions (including GGO and consolidation) were found in CT images of cases with comorbidity. The more comorbidities patients have, the more lesions CT images show.
Early-life gut dysbiosis linked to juvenile mortality in ostriches
Authors: Videvall Elin , Song Se Jin , Bensch Hanna M. , Strandh Maria , Engelbrecht Anel , Serfontein Naomi , Hellgren Olof , Olivier Adriaan , Cloete Schalk , Knight Rob , Cornwallis Charlie K.
Published: October 2020

Background

Imbalances in the gut microbial community (dysbiosis) of vertebrates have been associated with several gastrointestinal and autoimmune diseases. However, it is unclear which taxa are associated with gut dysbiosis, and if particular gut regions or specific time periods during ontogeny are more susceptible. We also know very little of this process in non-model organisms, despite an increasing realization of the general importance of gut microbiota for health.

Methods

Here, we examine the changes that occur in the microbiome during dysbiosis in different parts of the gastrointestinal tract in a long-lived bird with high juvenile mortality, the ostrich (Struthio camelus). We evaluated the 16S rRNA gene composition of the ileum, cecum, and colon of 68 individuals that died of suspected enterocolitis during the first 3 months of life (diseased individuals), and of 50 healthy individuals that were euthanized as age-matched controls. We combined these data with longitudinal environmental and fecal sampling to identify potential sources of pathogenic bacteria and to unravel at which stage of development dysbiosis-associated bacteria emerge.

Results

Diseased individuals had drastically lower microbial alpha diversity and differed substantially in their microbial beta diversity from control individuals in all three regions of the gastrointestinal tract. The clear relationship between low diversity and disease was consistent across all ages in the ileum, but decreased with age in the cecum and colon. Several taxa were associated with mortality (Enterobacteriaceae,Peptostreptococcaceae,Porphyromonadaceae,Clostridium), while others were associated with health (Lachnospiraceae,Ruminococcaceae,Erysipelotrichaceae,Turicibacter,Roseburia). Environmental samples showed no evidence of dysbiosis-associated bacteria being present in either the food, water, or soil substrate. Instead, the repeated fecal sampling showed that pathobionts were already present shortly after hatching and proliferated in individuals with low microbial diversity, resulting in high mortality several weeks later.

Conclusions

Identifying the origins of pathobionts in neonates and the factors that subsequently influence the establishment of diverse gut microbiota may be key to understanding dysbiosis and host development.
Effective mitigation strategy in early stage of COVID-19 pandemic in China
Authors: Yu Xiao-Yue , Xu Chen , Wang Hu-Wen , Chang Rui-Jie , Dong Yin-Qiao , Tsamlag Lhakpa , Zhang Shu-Xian , Yu Yue-Lin , Long Ru-Si , Wang Hui , Cai Yong
Published: October 2020

In the past five months, success in control the national epidemic of coronavirus disease 2019 (COVID-19) has been witnessed in China. The implementation of public health measures accounts for the success which include different interventions in the early or later stages of the outbreak. It is clear that although not all measures were universally effective worldwide, their achievements have been significant. More solidarity is needed to deal with this global pandemic with more learning and understanding. Understanding which of the public health interventions implemented in China were effective may provide ideas for international epidemic control.
The scale of the whale: using video-tag data to evaluate sea-surface ice concentration from the perspective of individual Antarctic minke whales
Authors: Linsky Jacob M. J. , Wilson Nicole , Cade David E. , Goldbogen Jeremy A. , Johnston David W. , Friedlaender Ari S.
Published: October 2020

Background

Advances in biologging technology allow researchers access to previously unobservable behavioral states and movement patterns of marine animals. To relate behaviors with environmental variables, features must be evaluated at scales relevant to the animal or behavior. Remotely sensed environmental data, collected via satellites, often suffers from the effects of cloud cover and lacks the spatial or temporal resolution to adequately link with individual animal behaviors or behavioral bouts. This study establishes a new method for remotely and continuously quantifying surface ice concentration (SIC) at a scale relevant to individual whales using on-animal tag video data.

Results

Motion-sensing and video-recording suction cup tags were deployed on 7 Antarctic minke whales (Balaenoptera bonaerensis) around the Antarctic Peninsula in February and March of 2018. To compare the scale of camera-tag observations with satellite imagery, the area of view was simulated using camera-tag parameters. For expected conditions, we found the visible area maximum to be ~ 100m2 which indicates that observations occur at an equivalent or finer scale than a single pixel of high-resolution visible spectrum satellite imagery. SIC was classified into one of six bins (0%, 1–20%, 21–40%, 41–60%, 61–80%, 81–100%) by two independent observers for the initial and final surfacing between dives. In the event of a disagreement, a third independent observer was introduced, and the median of the three observer’s values was used. Initial results (n = 6) show that Antarctic minke whales in the coastal bays of the Antarctic Peninsula spend 52% of their time in open water, and only 15% of their time in water with SIC greater than 20%. Over time, we find significant variation in observed SIC, indicating that Antarctic minke occupy an extremely dynamic environment. Sentinel-2 satellite-based approaches of sea ice assessment were not possible because of persistent cloud cover during the study period.

Conclusion

Tag-video offers a means to evaluate ice concentration at spatial and temporal scales relevant to the individual. Combined with information on underwater behavior, our ability to quantify SIC continuously at the scale of the animal will improve upon current remote sensing methods to understand the link between animal behavior and these dynamic environmental variables.
Content expectations and dropout in Dutch vocational education
Authors: Eegdeman Irene , van Klaveren Chris , Meeter Martijn
Published: October 2020

Unrealistic expectations with regard to one’s study program has been linked to negative consequences for future academic success. Previous studies that have shown this are often retrospective, however, and focus on performance-related expectations (e.g. expected grades), while unrealistic expectations about the required effort and the content of the program (content-related expectations) may be more relevant for explaining dropout in tertiary education. This study prospectively investigates whether the content-related expectations of 208 Dutch Sport Academy students elicited before the start of their vocational program are associated with subsequent dropout and academic performance. Our results show that dropped-out students did not differ in expected grades (even though they did differ in prevocational GPA). Moreover, their content-related expectations at the start of the program did not from successful students, nor were they any less realistic. Still, when retrospectively asked, 50% of the students answered that the concerning program did not fit. This suggests that retrospective reports of inadequate expectations may not reflect deficient expectations before starting the program. Instead, tertiary educational programs may defy expectations in both successful students and later unsuccessful students, with surprises being pleasant for successful students and unpleasant for unsuccessful ones.
Dynamic locking screws in proximal humeral plate osteosynthesis demonstrate superior fixation properties: a biomechanical study
Authors: Sandmann Gunther , Ateschrang Atesch , Freude Thomas , Stöckle Ulrich , Schmölz Werner , Konrads Christian , Döbele Stefan
Published: October 2020

Purpose

Angular stable implants reduced the complication rate in the treatment of humeral head fractures. But the failure rate is still high. To further reduce the risk of cut-out, cement augmentation of screws was introduced. A reason for failure of plate osteosynthesis might be the extremely high stiffness of the screw-plate interface leading to a loss of reduction and cut-out of screws. A more homogeneous distribution of the forces on all screws may avoid secondary dislocation. We hypothesize that dynamic osteosynthesis minimizes screw loosening and results in a higher load to failure than standard locking screws.

Methods

Twelve paired human humerus specimens were analysed. A standardized three-part fracture model with a metaphyseal defect was simulated. Within each pair of humeri, one was fixed with a Philos plate and standard locking screws (LS), whereas the other humerus was fixed with a Philos plate and dynamic locking screws (DLS). A cyclic varus-bending test or a rotation test with increasing loading force was performed until failure of the screw-bone-fixation.

Results

In the varus bending test, pairs failed by screw loosening in the humeral head. The LS-group reached 2901 (601–5201) load cycles until failure, while the DLS-group failed after 3731 (2001–5601) cycles. This corresponds to a median loading of 195 N for the LS-group and 235 N for the DLS-group (p = 0.028). In the rotation test the LS-group reached a median of 1101 (501–1501) load cycles until failure of fixation occurred, while the DLS-group failed after 1401 (401–2201) cycles (p = 0.225).

Conclusions

Plate fixation using dynamic locking screws for the treatment of proximal humerus fractures demonstrated more load cycles until failure compared to standard locking plate osteosynthesis.
Prevalence of placental malaria among asymptomatic pregnant women in Wolkite health center, Gurage zone, Southern Ethiopia
Authors: Solomon Absra , Kahase Daniel , Alemayhu Mihret
Published: October 2020

Background

Placental malaria (PM) is a major public health problem associated with adverse pregnancy outcomes such as low birth weight (LBW), preterm delivery and maternal anemia. The present study is aimed to determine the prevalence of placental malaria among asymptomatic pregnant women in Wolkite health center, Gurage zone, Southern Ethiopia.

Method

Facility-based cross-sectional study was carried out from June 2019 to August 2019. A total of 230 pregnant women were involved in the study where socio-demographic data, medical and obstetric history were collected using pretested structured questionnaires. Blood samples were collected at delivery from maternal capillary, placenta and umbilical cord for the detection of malarial parasite. Maternal hematocrit was determined to screen for anemia.

Result

In this study, the prevalence of placental malaria, peripheral malaria and umbilical cord malaria was 3.9% (9/230), 15.2% (35/230) and 2.6% (6/230) respectively.Plasmodium falciparumandPlasmodium vivaxwere detected by microscopy. All babies with positive umbilical cord blood films were born from a mother with placental malaria. Maternal anemia was recorded in 58.3% of the women. In univariate analysis, placental malaria was significantly associated with LBW (p < 0.001) unlike parity and maternal anemia.

Conclusion

Placental malaria among asymptomatic pregnant women is low in Wolkite health centre, Gurage zone in Southern Ethiopia. Moreover, placental malaria was strongly associated with LBW. Thus, further strengthening the existing prevention and control activities and screening of asymptomatic pregnant women as part of routine antenatal care service is very essential.
Observing maturing source rocks on seismic reflection data
Authors: Matava Tim , Keys Robert G. , Ohm Sverre E. , Volterrani Stefano
Published: October 2020

Hydrocarbon generation in a source rock is a complex, irreversible phase change that occurs when a source rock is heated during burial to change the phase to a fluid. The fluid density is less than the kerogen density; therefore, in a closed or partially closed system, the volume of the pore space occupied by fluids increases. Burial also increases the effective stress, which leads to compaction and a significant reduction in porosity. The challenge of identifying source rocks on seismic data then becomes differentiating the smaller porosity increase due to hydrocarbon formation from the larger porosity decrease associated with burial. We have used a calibrated rock-physics model to indicate that [Formula: see text] and porosity data can be used to predict the P- and S-wave velocities and the density in wells over large sedimentary sections, including a source rock of variable maturity. These well data and models indicate that the difference between an immature and mature source rock is an increase in porosity (lower density) relative to compacting, nonsource rock sediments. We use these results to identify a potential source interval in the Orphan Basin in Eastern Canada on 2D regional seismic data. We find that the full stack amplitude response of a maturing source rock is significant during the main phase of generation (0.2 < transformation ratio < 0.8) relative to the surrounding sediments. Regional scale consistency of the amplitude response with the kerogen maturity model from an integrated basin simulator reduces exploration risk because of the independence of the thermal model from the seismic amplitude response. Finally, combining the seismic response with the source rock maturity model provides insight into the likely kerogen kinetics. Most of applications require regional data sets to capture the maturity window; however, applications are also possible around allochthonous salt where geometries can lead to local changes in the heat flow.
Seismic-based characterization of reservoir heterogeneity within the Meramec interval of the STACK play, Central Oklahoma
Authors: Neely William , Ismail Ahmed , Ibrahim Mohammed , Puckette James
Published: October 2020

The Meramec interval within the Sooner Trend Anadarko Canadian Kingfisher (“STACK”) play of the Anadarko Basin in central Oklahoma has recently been at the epicenter of increased exploration and production of oil and gas. It has become one of the top target intervals of the “mid-continent” aided by technological advancements in horizontal drilling and completion techniques. The Meramec interval, mainly composed of argillaceous siliciclastic sediments with varying amounts of carbonate cement, exhibits high porosity heterogeneity, which is theorized to be caused by varying amounts of clay and postdepositional calcite cement. Characterization of the porosity heterogeneity in the Meramec interval will improve our understanding of the wide range in Meramec oil and gas production volumes and reduce the risk associated with drilling and completion techniques. We completed an initial interpretation followed by inversion of 3D seismic data in which we generated a detailed characterization of the porosity heterogeneity and overall reservoir quality within the Meramec interval over an area of approximately 150 square kilometers. We then used the 3D seismic volume and available well logs to map the vertical and lateral extents of the Meramec interval and identify possible structural elements that could affect the reservoir quality. A petrophysical analysis of the well logs confirmed porosity heterogeneity and variations in volumetric calculations of clay and carbonate minerals. Finally, we generated a set of porosity volumes using the acoustic impedance from seismic inversion and probabilistic neural network methods. The derived porosity volume helped us identify porous and nonporous intervals within the Meramec throughout the study area. The results improved our understanding of Meramec heterogeneity, further reducing the risk associated with well planning, drilling, and completion.
Buddhism during the Chosŏn Dynasty (1392–1910): A Collective Trauma?
Authors: Kim Hwansoo
Published: October 2020

An increasing number of recent scholars have challenged the narrative of Korean Buddhism as persecuted, isolated, and debased under the Neo-Confucian orthodoxy of the Chosŏn dynasty (1392–1910). These scholars have revealed the continued support from both the state and Confucian aristocrats afforded to Buddhism; the friendship between yangbans and monastics; and the recognition of monastics’ role in Chosŏn society. While these insights provide a welcome nuance to a consideration of the period, it should be also recognized that the anti-Buddhist paradigm was a pervasive norm at the state and local levels throughout the Chosŏn era. The perception that Buddhism was heretical and that monastics were socially inferior was so deeply ingrained in the minds of aristocrats and the populace for so long that monastics developed a sense of collective trauma. This article revisits the vicissitudes of Chosŏn Buddhism by considering an incident that took place in the 1930s in colonial Korea. This case will help scholars of Korean history and Buddhism understand how colonial-period monastics acted from the trauma of the anti-Buddhist paradigm of the Chosŏn dynasty.
Phyllotaxis as geometric canalization during plant development
Authors: Godin Christophe , Golé Christophe , Douady Stéphane
Published: October 2020

Why living forms develop in a relatively robust manner, despite various sources of internal or external variability, is a fundamental question in developmental biology. Part of the answer relies on the notion of developmental constraints: at any stage of ontogenesis, morphogenetic processes are constrained to operate within the context of the current organism being built. One such universal constraint is the shape of the organism itself, which progressively channels the development of the organism toward its final shape. Here, we illustrate this notion with plants, where strikingly symmetric patterns (phyllotaxis) are formed by lateral organs. This Hypothesis article aims first to provide an accessible overview of phyllotaxis, and second to argue that the spiral patterns in plants are progressively canalized from local interactions of nascent organs. The relative uniformity of the organogenesis process across all plants then explains the prevalence of certain patterns in plants, i.e. Fibonacci phyllotaxis.
Flight muscle power increases with strain amplitude and decreases with cycle frequency in zebra finches (Taeniopygia guttata)
Authors: Bahlman Joseph W. , Baliga Vikram B. , Altshuler Douglas L.
Published: October 2020

Birds that use high flapping frequencies can modulate aerodynamic force by varying wing velocity, which is primarily a function of stroke amplitude and wingbeat frequency. Previous measurements from zebra finches (Taeniopygia guttata) flying across a range of speeds in a wind tunnel demonstrate that although the birds modulated both wingbeat kinematic parameters, they exhibited greater changes in stroke amplitude. These two kinematic parameters contribute equally to aerodynamic force, so the preference for modulating amplitude over frequency may instead derive from limitations of muscle physiology at high frequency. We tested this hypothesis by developing a novel in situ work loop approach to measure muscle force and power output from the whole pectoralis major of zebra finches. This method allowed for multiple measurements over several hours without significant degradation in muscle power. We explored the parameter space of stimulus, strain amplitude and cycle frequencies measured previously from zebra finches, which revealed overall high net power output of the muscle, despite substantial levels of counter-productive power during muscle lengthening. We directly compared how changes to muscle shortening velocity via strain amplitude and cycle frequency affected muscle power. Increases in strain amplitude led to increased power output during shortening with little to no change in power output during lengthening. In contrast, increases in cycle frequency did not lead to increased power during shortening but instead increased counter-productive power during lengthening. These results demonstrate why at high wingbeat frequency, increasing wing stroke amplitude could be a more effective mechanism to cope with increased aerodynamic demands.
Hybrid Electrocatalytic Nanocomposites Based on Carbon Nanotubes/Nickel Oxide/Nafion toward an Individual and Simultaneous Determination of Serotonin and Dopamine in Human Serum
Authors: Mool-am-kha Pijika , Themsirimongkon Suwaphid , Saipanya Surin , Saianand Gopalan , Tuantranont Adisorn , Karuwan Chanpen , Jakmunee Jaroon
Published: October 2020

The design and development of facile, rapid, selective, and sensitive electroanalytical methods for the simultaneous determination of serotonin (ST) along with other interfering species are in huge demand. To address this, herein, we report an efficient electrochemical sensing platform for the individual and simultaneous determination of ST and dopamine (DA) in human serum. The sensing system was judicially constructed by hybrid electrocatalytic nanocomposites composed of carbon nanotubes/nickel oxide/carbon black/Nafion modified screen-printed carbon electrode (CNT-NiO-CB/Nafion/SPCE). The structural, morphological, and electrochemical properties of the as-synthesized/fabricated materials and electrodes were thoroughly analyzed through appropriate instrumentations (scanning/transmission electron microscopy, electron microscopy, X-ray photoelectron spectroscopy, electrochemical impedance spectroscopy, etc.). Besides, the experimental parameters of electrochemical measurements, such as varying amounts (CNT-NiO-CB/Nafion), pH, conditioning potential, time, modulation amplitude, and step potential, have been carefully optimized. The as-fabricated newly designed sensor exhibits superior analytical performance such as wide linear range (0.06–7.50 µM ST and 0.08–6.00 µM DA), low limit detection of (11 nM ST and 11 nM DA), high reproducibility (RSD = 5.74% ST and 7.74% DA) indicating excellent selectivity, stability, sensitivity along with good recovery range.
Anti-hypertensive vasodilatory action of Gynura procumbens mediated by kaempferol 3-O-rutinoside
Authors: Shahlehi Syahirah , Azizi Aziemah , Tengah Asrin , Amdani Siti Nornadhirah , Petalcorin Mark I. R.
Published: October 2020

Introduction: Gynura procumbens (GP), otherwise known as longevity spinach or “Sambung Nyawa” in Malay, is an evergreen herb found in Africa and Southeast Asian countries (including Brunei) used traditionally to treat various diseases such as fever, diabetes and hypertension. We examined GP’s vasodilatory action to determine its possible role via the cholinergic-mediated pathway.

Methods: GP leaves were prepared by filtration and evaporation to obtain the aqueous (AEGP) and methanol (MEGP) extracts followed by screening for phytochemical constituents. The total phenol, total flavonoid and flavonol contents were determined using the corresponding Folin–Ciocalteau, and aluminium colorimetric methods and the presence of kaempferol 3-O-rutinoside in the extracts was detected using HPLC analysis. Organ bath studies were conducted to determine the vasodilatory activity using intact and denuded isolated rat aortic rings by exposure to either increasing concentration of extracts (0.25, 0.5, 1.0, and 2.0 mg/mL) or 10 µg/mL kaempferol 3-O-rutinoside in the presence or absence of acetylcholine (ACh) after pre-contraction by noradrenaline (NA).

Results: MEGP contained more phytochemical constituents and higher content of total flavonoid and total flavonol but less phenolic content than AEGP. Furthermore, MEGP yielded a 20% elevated amount of kaempferol 3-O-rutinoside than AEGP. Both extracts significantly amplified ACh-endothelium dependent vasodilation and mediated relaxation at 1 mg/mL in endothelium-intact and endothelium-denuded aortic rings with MEGP as a more effective vasodilator than AEGP. Overall, these results imply the involvement of extracts in potentiating cholinergic pathway, which might be mediated by kaempferol, as shown by its vasorelaxation effects in endothelium-intact and –denuded aorta.

Conclusions: The present findings demonstrate that the vasodilatory activities of the two Gynura procumbens extracts, AEGP and MEGP, in thoracic aorta rings isolated from rats are potentially mediated via a cholinergic pathway through the action of a flavonoid particularly kaempferol 3-O-rutinoside.
SARS-CoV-2 RNA detected in blood products from patients with COVID-19 is not associated with infectious virus
Authors: Andersson Monique I. , Arancibia-Carcamo Carolina V. , Auckland Kathryn , Baillie J. Kenneth , Barnes Eleanor , Beneke Tom , Bibi Sagida , Brooks Tim , Carroll Miles , Crook Derrick , Dingle Kate , Dold Christina , Downs Louise O. , Dunn Laura , Eyre David W. , Gilbert Jaramillo Javier , Harvala Heli , Hoosdally Sarah , Ijaz Samreen , James Tim , James William , Jeffery Katie , Justice Anita , Klenerman Paul , Knight Julian C. , Knight Michael , Liu Xu , Lumley Sheila F. , Matthews Philippa C. , McNaughton Anna L. , Mentzer Alexander J. , Mongkolsapaya Juthathip , Oakley Sarah , Oliveira Marta S. , Peto Timothy , Ploeg Rutger J. , Ratcliff Jeremy , Robbins Melanie J. , Roberts David J. , Rudkin Justine , Russell Rebecca A. , Screaton Gavin , Semple Malcolm G. , Skelly Donal , Simmonds Peter , Stoesser Nicole , Turtle Lance , Wareing Susan , Zambon Maria
Published: October 2020

Background: Laboratory diagnosis of SARS-CoV-2 infection (the cause of COVID-19) uses PCR to detect viral RNA (vRNA) in respiratory samples. SARS-CoV-2 RNA has also been detected in other sample types, but there is limited understanding of the clinical or laboratory significance of its detection in blood.

Methods: We undertook a systematic literature review to assimilate the evidence for the frequency of vRNA in blood, and to identify associated clinical characteristics. We performed RT-PCR in serum samples from a UK clinical cohort of acute and convalescent COVID-19 cases (n=212), together with convalescent plasma samples collected by NHS Blood and Transplant (NHSBT) (n=462 additional samples). To determine whether PCR-positive blood samples could pose an infection risk, we attempted virus isolation from a subset of RNA-positive samples.

Results: We identified 28 relevant studies, reporting SARS-CoV-2 RNA in 0-76% of blood samples; pooled estimate 10% (95%CI 5-18%). Among serum samples from our clinical cohort, 27/212 (12.7%) had SARS-CoV-2 RNA detected by RT-PCR. RNA detection occurred in samples up to day 20 post symptom onset, and was associated with more severe disease (multivariable odds ratio 7.5). Across all samples collected ≥28 days post symptom onset, 0/494 (0%, 95%CI 0-0.7%) had vRNA detected. Among our PCR-positive samples, cycle threshold (ct) values were high (range 33.5-44.8), suggesting low vRNA copy numbers. PCR-positive sera inoculated into cell culture did not produce any cytopathic effect or yield an increase in detectable SARS-CoV-2 RNA. There was a relationship between RT-PCR negativity and the presence of total SARS-CoV-2 antibody (p=0.02).

Conclusions: vRNA was detectable at low viral loads in a minority of serum samples collected in acute infection, but was not associated with infectious SARS-CoV-2 (within the limitations of the assays used). This work helps to inform biosafety precautions for handling blood products from patients with current or previous COVID-19.
A Defeasible Calculus for Zetetic Agents
Authors: Millson Jared
Published: October 2020

The study of defeasible reasoning unites epistemologists with those working in AI, in part, because both are interested in epistemic rationality. While it is traditionally thought to govern the formation and (with)holding of beliefs, epistemic rationality  may also apply to the interrogative attitudes associated with our core epistemic practice of inquiry, such as wondering, investigating, and curiosity.  Since generally intelligent systems should be capable of rational information-seeking behavior, AI researchers have a natural interest in the norms that govern interrogative attitudes. In this paper, we argue that these norms can be modeled via defeasible inferences to and from questions, i.e. erotetic inferences. We offer a sequent calculus that accommodates the unique features of ``erotetic defeat"  and that exhibits the computational properties needed to inform the design of inquisitive systems. The calculus presented here is an improved version of the one presented in Millson (2019), extended to cover a new class of defeasible erotetic inferences.The study of defeasible reasoning unites epistemologists with those working in AI, in part, because both are interested in epistemic rationality. While it is traditionally thought to govern the formation and (with)holding of beliefs, epistemic rationality may also apply to the interrogative attitudes associated with our core epistemic practice of inquiry, such as wondering, investigating, and curiosity. Since generally intelligent systems should be capable of rational inquiry, AI researchers have a natural interest in the norms that govern interrogative attitudes. Following its recent coinage, we use the term “zetetic” to refer to the properties and norms associated with the capacity to inquire. In this paper, we argue that zetetic norms can be modeled via defeasible inferences to and from questions – a.k.a erotetic inferences – in a manner similar to the way norms of epistemic rationality are represented by defeasible inference rules. We offer a sequent calculus that accommodates the unique features of “erotetic defeat" and that exhibits the computational properties needed to inform the design of zetetic agents. The calculus presented here is an improved version of the one presented in (Millson, 2019), extended to cover a new class of defeasible erotetic inferences.
Shipping Consolidation Across Two Warehouses with Delivery Deadline and Expedited Options for E-commerce and Omni-channel Retailers
Authors: Wei Lai , Kapuscinski Roman , Jasin Stefanus
Published: October 2020

Problem definition: Shipment consolidation (i.e., shipping multiple orders together instead of shipping them separately) is commonly used to decrease total shipping costs. However, when the delivery of some orders is delayed, so they can be consolidated with future orders, a more expensive expedited shipment may be needed to meet shorter deadlines. In this paper, we study the optimal consolidation policy focusing on the trade-off between economies of scale due to combining orders and expedited shipping costs, in the setting of two warehouses. Academic/practical relevance: Our work is motivated by the application of fulfillment consolidation in e-commerce and omni-channel retail, especially with the rise of so-called on-demand logistics services. Sellers have the flexibility to take advantage of consolidation by deciding when to ship the orders and from which warehouse to fulfill the orders, as long as the orders’ deadlines are met. Methodology: We use Dynamic Programming to study the optimal policy and its structure. We also conduct extensive simulation tests to evaluate the performance of heuristics that are based on structures of the optimal policies. Results: The optimal policies and their structures are characterized. Using the insights of these structural properties, we propose two easily implementable heuristics that perform within 1%–2% of the optimal solution and outperform other benchmark consolidation methods in numerical tests. Managerial implications: Consolidation is shown to significantly reduce the outbound shipping costs. Retailers can take advantage of it to effectively improve the standard policies by simply applying the threshold-form heuristics we propose.
Between Home and Work: Commuting as an Opportunity for Role Transitions
Authors: Jachimowicz Jon M. , Cunningham Julia Lee , Staats Bradley R. , Gino Francesca , Menges Jochen I.
Published: October 2020

Across the globe, every workday people commute an average of 38 minutes each way, yet surprisingly little research has examined the implications of this daily routine for work-related outcomes. Integrating theories of boundary work, self-control, and work-family conflict, we propose that the commute to work serves as a liminal role transition between home and work roles, prompting employees to engage in boundary management strategies. Across three field studies (n = 1,736), including a four-week-long intervention study, we find that lengthy morning commutes are more aversive for employees with lower trait self-control and greater work-family conflict, leading to decreased job satisfaction and increased turnover. In addition, we find that employees who engage in a specific boundary management strategy we term role-clarifying prospection (i.e., thinking about the upcoming work role) are less likely to be negatively affected by lengthy commutes to work. Results further show that employees with higher levels of trait self-control are more likely to engage in role-clarifying prospection, and employees who experience higher levels of work-family conflict are more likely to benefit from role-clarifying prospection. Although the commute to work is typically seen as an undesirable part of the workday, our theory and results point to the benefits of using it as an opportunity to transition into one’s work role.
ECG of the month
Authors: Bloe Charlie
Published: October 2020

In this issue's ECG of the month, Charlie Bloe presents the case of a smoker with a history of hypertension who called 999 reporting central chest pain.
Optical difference in the frequency domain to suppress disturbance for wearable electronics
Authors: Li Haicheng , Wang Zhouheng , Cao Yu , Ma Yinji , Feng Xue
Published: October 2020

Measurements based on optics offer a wide range of unprecedented opportunities in the biological application due to the noninvasive or non-destructive detection. Wearable skin-like optoelectronic devices, capable of deforming with the human skin, play significant roles in future biomedical engineering such as clinical diagnostics or daily healthcare. However, the detected signals based on light intensity are very sensitive to the light path. The performance degradation of the wearable devices occurs due to device deformation or motion artifact. In this work, we propose the optical difference in the frequency domain of signals for suppressing the disturbance generated by wearable device deformation or motion artifact during the photoplethysmogram (PPG) monitoring. The signal processing is simulated with different input waveforms for analyzing the performance of this method. Then we design and fabricate a wearable optoelectronic device to monitor the PPG signal in the condition of motion artifact and use the optical difference in the frequency domain of signals to suppress irregular disturbance. The proposed method reduced the average error in heart rate estimation from 13.04 beats per minute (bpm) to 3.41 bpm in motion and deformation situations. These consequences open up a new prospect for improving the performance of the wearable optoelectronic devices and precise medical monitoring in the future.
Three-dimensional label-free imaging and quantification of migrating cells during wound healing
Authors: Lee Ariel J. , Hugonnet Herve , Park WeiSun , Park YongKeun
Published: October 2020

The wound-healing assay is a simple but effective tool for studying collective cell migration (CCM) that is widely used in biophysical studies and high-throughput screening. However, conventional imaging and analysis methods only address two-dimensional (2D) properties in a wound healing assay, such as gap closure rate. This is unfortunate because biological cells are complex 3D structures, and their dynamics provide significant information about cell physiology. Here, we presented 3D label-free imaging for wound healing assays and investigated the 3D dynamics of CCM using optical diffraction tomography. High-resolution subcellular structures as well as their collective dynamics were imaged and analyzed quantitatively.
Hyperbolic surface waves on anisotropic materials without hyperbolic dispersion
Authors: Repän Taavi , Takayama Osamu , Lavrinenko Andrei
Published: October 2020

We theoretically analyze directional surface electromagnetic waves supported at an interface between an isotropic medium and anisotropic metal with effective uniaxial negative permittivity. We identify two types of surface wave solutions, resulting in unique hyperbolic dispersion in the wavevector space. Such anisotropic metal can be realized by alternating dielectric and metallic layers with deep subwavelength thicknesses or metallic nanowires in dielectric host. Such systems serve as a platform for many applications in nanophotonics.
Plasmonic gold-cellulose nanofiber aerogels
Authors: Liu Qingkun , Mundoor Haridas , Sheetah Ghadah H. , Smalyukh Ivan I.
Published: October 2020

Assembly of plasmonic nanomaterials into a low refractive index medium, such as an aerogel, holds a great promise for optical metamaterials, optical sensors, and photothermal energy converters. However, conventional plasmonic aerogels are opaque and optically isotropic composites, impeding them from being used as low-loss or polarization-dependent optical materials. Here we demonstrate a plasmonic-cellulose nanofiber composite aerogel that comprises of well-dispersed gold nanorods within a cellulose nanofiber network. The cellulose aerogel host is highly transparent owing to the small scattering cross-section of the nanofibers and forms a nematic liquid crystalline medium with strong optical birefringence. We find that the longitudinal surface plasmon resonance peak of gold nanorods shows a dramatic shift when probed for the cellulose aerogel compared with the wet gels. Simulations reveal the shift of surface plasmon resonance peak with gel drying can be attributed to the change of the effective refractive index of the gels. This composite material may provide a platform for three- dimensional plasmonic devices ranging from optical sensors to metamaterials.
Analog-controlled light microshutters based on electrothermal actuation for smart windows
Authors: Xiao Lei , Ding Yingtao , Wang Peng , Xie Huikai
Published: October 2020

Smart windows for sunlight control play an important role in modern green buildings. Electrically-controllable light microshutters provide a promising solution for smart windows. However, most of reported microshutters work under on/off binary mode. In this work, an electrothermally actuated microshutter that can achieve analog light control is proposed. The microshutter consists of an array of electrothermal Al/SiO2 bimorph cantilever plates suspended over a through-silicon cavity. The device is fabricated by a combination of surface- and bulk- micromachining processes. Test experiments show that for a single microshutter pixel, the device opening ratio can be tuned continuously from 78.6% (Open state, 0 V) all the way down to nearly 0% (Close state, 8 V) with a small hysteresis. For the entire array of 2 × 5 microshutters, the light transmission ratio varies continuously from 63.3% to 3.6% when the applied voltage is increased from 0 to 7.3 V. Furthermore, the response time, long-term reliability and window-like function of the microshutter are tested.
High-fidelity off-axis digital optical phase conjugation with transmission matrix assisted calibration
Authors: Mididoddi Chaitanya K. , Lennon Rachel A. , Li Shuhui , Phillips David B.
Published: October 2020

The spatial information carried by light is scrambled when it propagates through a scattering medium, such as frosted glass, biological tissue, turbulent air, or multimode optical fibres. Digital optical phase conjugation (DOPC) is a technique that ‘pre-aberrates’ an illuminating wavefront to compensate for scatterer induced distortion. DOPC systems act as phase-conjugate mirrors: they require a camera to holographically record a distorted wavefront emanating from the scatterer and a spatial light modulator (SLM) to synthesize a phase conjugate of the measured wavefront, which is sent back through the scatterer thus creating a time-reversed copy of the original optical field. High-fidelity DOPC can be technically challenging to achieve as it typically requires pixel-perfect alignment between the camera and SLM. Here we describe a DOPC system in which the normally stringent alignment criteria are relaxed. In our system the SLM and camera are placed in-line in the same optical path from the sample, and the SLM is used in an off-axis configuration. This means high-precision alignment can be achieved by measurement of the transmission matrix (TM) mapping optical fields from the SLM to the camera and vice-versa, irrespective of their relative position. The TM also absorbs and removes other aberrations in the optical system, such as the curvature of the SLM and camera chips. Using our system we demonstrate high-fidelity focussing of light through two ground glass diffusers with a peak-intensity to mean-background ratio of ∼700. We provide a step-by-step guide detailing how to align this system and discuss the trade-offs with alternative configurations. We also describe how our setup can be used as a ‘single-pixel camera’ based DOPC system, offering potential for DOPC at wavelengths in which cameras are not available or are prohibitively expensive.