bluuebunny/crossref_metadata_2025 huggingface dataset:
Transient optical non-linearity in p-Si induced by a few cycle extreme THz field
Authors: Savel’ev Andrei , Chefonov Oleg , Ovchinnikov Andrei , Rubtsov Alexey , Shkurinov Alexander , Zhu Yiming , Agranat Mikhail , Fortov Vladimir
Published: January 2021

We study the impact of a few cycle extreme terahertz (THz) radiation (the field strength ETHz ∼1–15 MV/cm is well above the DC-field breakdown threshold) on a p-doped Si wafer. Pump-probe measurements of the second harmonic of a weak infrared probe were done at different THz field strengths. The second harmonic yield has an unusual temporal behavior and does not follow the common instantaneous response,

∝

E

TH

z

2

. These findings were attributed to: (i) the lattice strain by the ponderomotive force of the extreme THz pulse at the maximal THz field strength below 6 MV/cm and (ii) the modulation of the THz field-induced impact ionization rate at the optical probe frequency (due to the modulation of the free carriers’ drift kinetic energy from the probe field) at the THz field strength above 6–8 MV/cm.
Experimentally measuring the mode indices of Laguerre-Gaussian beams by weak measurement
Authors: Zhu Jing , Zhang Pei , Wang Feiran , Wang Yunlong , Li Qichang , Liu Ruifeng , Wang Jinwen , Gao Hong , Li Fuli
Published: January 2021

As a special experimental technique, weak measurements extract very little information from the measured system and does not cause the measured state to collapse. When coupling the Laguerre-Gaussian (LG) state with a well-defined pre- and post-selected system of a weak measurement process, there will be an indirect interconnection between the expected value of coordinate operators of the final state and the mode indices of the measured LG state. The mode of the light is impacted very slightly after the weak measurement. Based on this we propose an experiment scheme and have managed to experimentally measure the mode indices of LG beams spanning from l = −6 to l = +6, p = 0 to p = +8 accurately with the final intensity distributions approximatly at their origin.
Strong-coupling-assisted formation of coherent radiation below the lasing threshold
Authors: Doronin I. V. , Zyablovsky A. A. , Andrianov E. S.
Published: January 2021

The creation of nanoscale lasers that operate above a coherent threshold is a challenging problem. We propose a way to circumvent this issue using systems in which a strong coupling regime is achieved between the light and the active medium. In the strong coupling regime, energy oscillations take place between the EM field in the cavity and the atoms. We show that by applying appropriate time modulation to the pumping, it is possible to control these energy oscillations in such a way that coherence in the laser system appears below the lasing threshold. In this approach, the radiation linewidth is two orders of magnitude smaller than the linewidth of a conventional laser for the same photon number. In addition, the second order coherence function of the output radiation is reduced from two to one before the system reaches a positive population inversion. Our results pave the way for the creation of nanoscale sources of coherent radiation that can operate below the lasing threshold.
Deep learning–based moiré-fringe alignment with circular gratings for lithography
Authors: Wang Nan , Jiang Wei , Zhang Yu
Published: January 2021

In lithography, misalignment measurement with a large range and high precision in two dimensions for the overlay is a fundamental but challenging problem. For moiré-based misalignment measurement schemes, one potential solution is considered to be the use of circular gratings, whose formed moiré fringes are symmetric, isotropic, and aperiodic. However, due to the absence of proper analytical arithmetic, the measurement accuracy of such schemes is in the tens of nanometers, resulting in their application being limited to only coarse alignments. To cope with this problem, we propose a novel deep learning–based misalignment measurement strategy inspired by deep convolutional neural networks. The experimental results show that the proposed scheme can achieve nanoscale accuracy with micron-scale circular alignment marks. Relative to the existing strategies, this strategy has much higher precision in misalignment measurement and much better robustness to fabrication defects and random noise. This enables a one-step two-dimensional nanoscale alignment scheme for proximity, x-ray, extreme ultraviolet, projective, and nanoimprint lithographies.
Postfilament supercontinuum on 100  m path in air
Authors: Kosareva O. , Panov N. , Shipilo D. , Mokrousova D. , Nikolaeva I. , Mitina E. , Koribut A. , Reutov A. , Rizaev G. , Couairon A. , Houard A. , Skryabin D. , Saletskiy A. , Savel’ev A. , Seleznev L. , Ionin A. , Chin S. L.
Published: January 2021

Pulses at 744 nm with 90 fs duration, 6 mJ energy, and a weakly divergent wavefront propagate for more than 100 m and generate a filament followed by an unprecedently long high intensity (

≥
1

T
W

/

c
m

2

) light channel. Over a 20 m long sub-section of this channel, the pulse energy is transferred continuously to the infrared wing, forming spectral humps that extend up to 850 nm. From 3D+time carrier-resolved simulations of 100 m pulse propagation, we show that spectral humps indicate the formation of a train of femtosecond pulses appearing at a predictable position in the propagation path.
Transient-grating single-shot supercontinuum spectral interferometry (TG-SSSI)
Authors: Hancock S. W. , Zahedpour S. , Milchberg H. M.
Published: January 2021

We present a technique for the single-shot measurement of the spatiotemporal (1D

s
p
a
c
e

+

t
i
m
e

) amplitude and phase of an ultrashort laser pulse. The method, transient grating single-shot supercontinuum spectral interferometry (TG-SSSI), is demonstrated by the space–time imaging of short pulses carrying spatiotemporal optical vortices. TG-SSSI is well suited for characterizing ultrashort laser pulses that contain singularities associated with spin/orbital angular momentum or polarization.
High-speed programmable lithium niobate thin film spatial light modulator
Authors: Ye Xuanchao , Ni Fengchao , Li Honggen , Liu Haigang , Zheng Yuanlin , Chen Xianfeng
Published: January 2021

High-speed spatial modulation of light is the key technology in various applications, such as optical communications, imaging through scattering media, video projection, pulse shaping, and beam steering, in which spatial light modulators (SLMs) are the underpinning devices. Conventional SLMs, such as liquid crystal (LC), digital micromirror device (DMD), and micro-electro-mechanical system (MEMS) ones, operate at a typical speed on the order of several kilohertz as limited by the slow response of the pixels. Achieving high-speed spatial modulation is still challenging and highly desired. Here, we demonstrate a one-dimensional (1D) high-speed programmable spatial light modulator based on the electro-optic effect in lithium niobate thin film, which achieves a low driving voltage of 10 V and an overall high-speed modulation speed of 5 MHz. Furthermore, we transfer an image by using parallel data transmission based on the proposed lithium niobate SLM as a proof-of-principle demonstration. Our device exhibits improved performance over traditional SLMs and opens new avenues for future high-speed and real-time applications, such as light detection and ranging (LiDAR), pulse shaping, and beam steering.
Why Lyme disease is common in the northern US, but rare in the south: The roles of host choice, host-seeking behavior, and tick density
Authors: Ginsberg Howard S. , Hickling Graham J. , Burke Russell L. , Ogden Nicholas H. , Beati Lorenza , LeBrun Roger A. , Arsnoe Isis M. , Gerhold Richard , Han Seungeun , Jackson Kaetlyn , Maestas Lauren , Moody Teresa , Pang Genevieve , Ross Breann , Rulison Eric L. , Tsao Jean I.
Published: January 2021

Lyme disease is common in the northeastern United States, but rare in the southeast, even though the tick vector is found in both regions. Infection prevalence of Lyme spirochetes in host-seeking ticks, an important component to the risk of Lyme disease, is also high in the northeast and northern midwest, but declines sharply in the south. As ticks must acquire Lyme spirochetes from infected vertebrate hosts, the role of wildlife species composition on Lyme disease risk has been a topic of lively academic discussion. We compared tick–vertebrate host interactions using standardized sampling methods among 8 sites scattered throughout the eastern US. Geographical trends in diversity of tick hosts are gradual and do not match the sharp decline in prevalence at southern sites, but tick–host associations show a clear shift from mammals in the north to reptiles in the south. Tick infection prevalence declines north to south largely because of high tick infestation of efficient spirochete reservoir hosts (rodents and shrews) in the north but not in the south. Minimal infestation of small mammals in the south results from strong selective attachment to lizards such as skinks (which are inefficient reservoirs for Lyme spirochetes) in the southern states. Selective host choice, along with latitudinal differences in tick host-seeking behavior and variations in tick densities, explains the geographic pattern of Lyme disease in the eastern US.
Anti-science kills: From Soviet embrace of pseudoscience to accelerated attacks on US biomedicine
Authors: Hotez Peter J.
Published: January 2021

The United States witnessed an unprecedented politicization of biomedical science starting in 2015 that has exploded into a complex, multimodal anti-science empire operating through mass media, political elections, legislation, and even health systems. Anti-science activities now pervade the daily lives of many Americans, and threaten to infect other parts of the world. We can attribute the deaths of tens of thousands of Americans from COVID-19, measles, and other vaccine-preventable diseases to anti-science. The acceleration of anti-science activities demands not only new responses and approaches but also international coordination. Vaccines and other biomedical advances will not be sufficient to halt COVID-19 or future potentially catastrophic illnesses, unless we simultaneously counter anti-science aggression.
MASSpy: Building, simulating, and visualizing dynamic biological models in Python using mass action kinetics
Authors: Haiman Zachary B. , Zielinski Daniel C. , Koike Yuko , Yurkovich James T. , Palsson Bernhard O.
Published: January 2021

Mathematical models of metabolic networks utilize simulation to study system-level mechanisms and functions. Various approaches have been used to model the steady state behavior of metabolic networks using genome-scale reconstructions, but formulating dynamic models from such reconstructions continues to be a key challenge. Here, we present the Mass Action Stoichiometric Simulation Python (MASSpy) package, an open-source computational framework for dynamic modeling of metabolism. MASSpy utilizes mass action kinetics and detailed chemical mechanisms to build dynamic models of complex biological processes. MASSpy adds dynamic modeling tools to the COnstraint-Based Reconstruction and Analysis Python (COBRApy) package to provide an unified framework for constraint-based and kinetic modeling of metabolic networks. MASSpy supports high-performance dynamic simulation through its implementation of libRoadRunner: the Systems Biology Markup Language (SBML) simulation engine. Three examples are provided to demonstrate how to use MASSpy: (1) a validation of the MASSpy modeling tool through dynamic simulation of detailed mechanisms of enzyme regulation; (2) a feature demonstration using a workflow for generating ensemble of kinetic models using Monte Carlo sampling to approximate missing numerical values of parameters and to quantify biological uncertainty, and (3) a case study in which MASSpy is utilized to overcome issues that arise when integrating experimental data with the computation of functional states of detailed biological mechanisms. MASSpy represents a powerful tool to address challenges that arise in dynamic modeling of metabolic networks, both at small and large scales.
Voxelized simulation of cerebral oxygen perfusion elucidates hypoxia in aged mouse cortex
Authors: Hartung Grant , Badr Shoale , Moeini Mohammad , Lesage Frédéric , Kleinfeld David , Alaraj Ali , Linninger Andreas
Published: January 2021

Departures of normal blood flow and metabolite distribution from the cerebral microvasculature into neuronal tissue have been implicated with age-related neurodegeneration. Mathematical models informed by spatially and temporally distributed neuroimage data are becoming instrumental for reconstructing a coherent picture of normal and pathological oxygen delivery throughout the brain. Unfortunately, current mathematical models of cerebral blood flow and oxygen exchange become excessively large in size. They further suffer from boundary effects due to incomplete or physiologically inaccurate computational domains, numerical instabilities due to enormous length scale differences, and convergence problems associated with condition number deterioration at fine mesh resolutions. Our proposed simple finite volume discretization scheme for blood and oxygen microperfusion simulations does not require expensive mesh generation leading to the critical benefit that it drastically reduces matrix size and bandwidth of the coupled oxygen transfer problem. The compact problem formulation yields rapid and stable convergence. Moreover, boundary effects can effectively be suppressed by generating very large replica of the cortical microcirculation in silico using an image-based cerebrovascular network synthesis algorithm, so that boundaries of the perfusion simulations are far removed from the regions of interest. Massive simulations over sizeable portions of the cortex with feature resolution down to the micron scale become tractable with even modest computer resources. The feasibility and accuracy of the novel method is demonstrated and validated with in vivo oxygen perfusion data in cohorts of young and aged mice. Our oxygen exchange simulations quantify steep gradients near penetrating blood vessels and point towards pathological changes that might cause neurodegeneration in aged brains. This research aims to explain mechanistic interactions between anatomical structures and how they might change in diseases or with age. Rigorous quantification of age-related changes is of significant interest because it might aide in the search for imaging biomarkers for dementia and Alzheimer’s disease.
ProMod3—A versatile homology modelling toolbox
Authors: Studer Gabriel , Tauriello Gerardo , Bienert Stefan , Biasini Marco , Johner Niklaus , Schwede Torsten
Published: January 2021

Computational methods for protein structure modelling are routinely used to complement experimental structure determination, thus they help to address a broad spectrum of scientific questions in biomedical research. The most accurate methods today are based on homology modelling, i.e. detecting a homologue to the desired target sequence that can be used as a template for modelling. Here we present a versatile open source homology modelling toolbox as foundation for flexible and computationally efficient modelling workflows. ProMod3 is a fully scriptable software platform that can perform all steps required to generate a protein model by homology. Its modular design aims at fast prototyping of novel algorithms and implementing flexible modelling pipelines. Common modelling tasks, such as loop modelling, sidechain modelling or generating a full protein model by homology, are provided as production ready pipelines, forming the starting point for own developments and enhancements. ProMod3 is the central software component of the widely used SWISS-MODEL web-server.
Epithelial cell-turnover ensures robust coordination of tissue growth in Drosophila ribosomal protein mutants
Authors: Akai Nanami , Ohsawa Shizue , Sando Yukari , Igaki Tatsushi
Published: January 2021

Highly reproducible tissue development is achieved by robust, time-dependent coordination of cell proliferation and cell death. To study the mechanisms underlying robust tissue growth, we analyzed the developmental process of wing imaginal discs inDrosophila Minutemutants, a series of heterozygous mutants for a ribosomal protein gene.Minuteanimals show significant developmental delay during the larval period but develop into essentially normal flies, suggesting there exists a mechanism ensuring robust tissue growth during abnormally prolonged developmental time. Surprisingly, we found that both cell death and compensatory cell proliferation were dramatically increased in developing wing pouches ofMinuteanimals. Blocking the cell-turnover by inhibiting cell death resulted in morphological defects, indicating the essential role of cell-turnover inMinutewing morphogenesis. Our analyses showed thatMinutewing discs elevate Wg expression and JNK-mediated Dilp8 expression that causes developmental delay, both of which are necessary for the induction of cell-turnover. Furthermore, forced increase in Wg expression together with developmental delay caused by ecdysone depletion induced cell-turnover in the wing pouches of non-Minuteanimals. Our findings suggest a novel paradigm for robust coordination of tissue growth by cell-turnover, which is induced when developmental time axis is distorted.
Major risk factors and histopathological profile of treatment failure, relapse and chronic patients with anthroponotic cutaneous leishmaniasis: A prospective case-control study on treatment outcome and their medical importance
Authors: Bamorovat Mehdi , Sharifi Iraj , Dabiri Shahriar , Shamsi Meymandi Simin , Karamoozian Ali , Amiri Rezvan , Heshmatkhah Amireh , Borhani Zarandi Mehdi , Aflatoonian Mohammad Reza , Sharifi Fatemeh , Kheirandish Reza , Hassanzadeh Saeid
Published: January 2021

Over the last years, there has been a remarkable increase in the number of unresponsive patients with anthroponotic cutaneous leishmaniasis (ACL) reported worldwide. The primary objective of this study was to explore the role of demographic, clinical and environmental risk related-factors in the development of treatment failure, relapse and chronic cases compared to responsive patients with ACL. Moreover, molecular, histopathological and immunohistochemical (IHC) findings between these forms were explored. This work was undertaken as a prospective and case-control study in southeastern Iran. Culture media and nested PCR were used to identify the causative agent. Univariate multinomial and multiple multinomial logistic regression models and the backward elimination stepwise method were applied to analyze the data. A P<0.05 was defined as significant. Also, for different groups, skin punch biopsies were used to study the histopathological and immunohistochemical (IHC) profile. All samples showed that L. tropica was the only etiological agent in all unresponsive and responsive patients with ACL. Data analysis represented that 8 major risk factors including nationality, age groups, occupation, marital status, history of chronic diseases, duration of the lesion, the lesion on face and presence of domestic animals in the house were significantly associated with the induction of unresponsive forms. The histopathological and immunohistochemical findings were different from one form to another. The present findings clearly demonstrated a positive relation between ACL and distinct demographic, clinical and environmental risk determinants. Knowledge of the main risk factors for ACL infection is crucial in improving clinical and public health strategies and monitor such perplexing factors.
Polymer-assisted intratumoral delivery of ethanol: Preclinical investigation of safety and efficacy in a murine breast cancer model
Authors: Nief Corrine , Morhard Robert , Chelales Erika , Adrianzen Alvarez Daniel , Bourla BS Ioanna , Lam Christopher T. , Sag Alan A. , Crouch Brian T. , Mueller Jenna L. , Katz David , Dewhirst Mark W. , Everitt Jeffrey I. , Ramanujam Nirmala
Published: January 2021

Focal tumor ablation with ethanol could provide benefits in low-resource settings because of its low overall cost, minimal imaging technology requirements, and acceptable clinical outcomes. Unfortunately, ethanol ablation is not commonly utilized because of a lack of predictability of the ablation zone, caused by inefficient retention of ethanol at the injection site. To create a predictable zone of ablation, we have developed a polymer-assisted ablation method using ethyl cellulose (EC) mixed with ethanol. EC is ethanol-soluble and water-insoluble, allowing for EC-ethanol to be injected as a liquid and precipitate into a solid, occluding the leakage of ethanol upon contact with tissue. The aims of this study were to compare the 1) safety, 2) release kinetics, 3) spatial distribution, 4) necrotic volume, and 5) overall survival of EC-ethanol to conventional ethanol ablation in a murine breast tumor model. Non-target tissue damage was monitored through localized adverse events recording, ethanol release kinetics with Raman spectroscopy, injectate distribution with in vivo imaging, target-tissue necrosis with NADH-diaphorase staining, and overall survival by proxy of tumor growth. EC-ethanol exhibited decreased localized adverse events, a slowing of the release rate of ethanol, more compact injection zones, 5-fold increase in target-tissue necrosis, and longer overall survival rates compared to the same volume of pure ethanol. A single 150 μL dose of 6% EC-ethanol achieved a similar survival probability rates to six daily 50 μL doses of pure ethanol used to simulate a slow-release of ethanol over 6 days. Taken together, these results demonstrate that EC-ethanol is safer and more effective than ethanol alone for ablating tumors.
CXCR4 expression in lung carcinogenesis: Evaluating gender-specific differences in survival outcomes based on CXCR4 expression in early stage non-small cell lung cancer patients
Authors: Fung Andrea S. , Kopciuk Karen , Dean Michelle L. , D’Silva Adrijana , Otsuka Shannon , Klimowicz Alexander , Hao Desiree , Morris Don , Bebb D. Gwyn
Published: January 2021

Introduction

Evidence suggests that the expression of certain cytokine receptors increases with lung cancer evolution. Overexpression of the cytokine receptor CXCR4 is associated with poor outcomes in stage IV non-small cell lung cancer (NSCLC), with shorter survival in females with high CXCR4 expression. This study quantifies CXCR4 expression in early stage disease and evaluates its association with gender-specific recurrence-free (RFS) and overall survival (OS) in resected stage I-III NSCLC patients.

Methods

Patient characteristics and clinical outcomes were obtained from the Glans-Look Lung Cancer (G-LLC) database for early stage NSCLC patients diagnosed between 2003–2006 at the Tom Baker Cancer Centre (TBCC). CXCR4 expression was quantified on tissue microarrays (TMA). Median RFS and OS were evaluated by gender using Kaplan-Meier analyses. CXCR4 expression and outcome data were analyzed using Cox proportional hazards (PH) and multi-state models (MSM).

Results

176 stage I-III NSCLC patients were identified. CXCR4 expression was lower in early stage NSCLC patients, with a mean CXCR4 expression of 1729 (SD 1083) compared to 2640 (SD 1541) in stage IV patients. On Kaplan-Meier, median RFS by gender was similar (male 52.8 months vs. female 54.5 months) as was median OS (male 80.9 months vs. female 89.0 months), and there was no significant difference in RFS (p = 0.60) or OS (p = 0.30) by gender and CXCR4 groups over follow-up. By multivariable analysis, CXCR4 expression was not prognostic for RFS (Hazard Ratio (HR) = 1.00, p = 0.73) or OS (HR = 1.00, p = 0.44), and no gender difference was observed.

Conclusions

CXCR4 expression increases with stage progression in NSCLC but is not prognostic in early stage NSCLC patients of either gender. Mechanisms by which CXCR4 expression increases during lung carcinogenesis warrant further exploration and testing in clinical trials.
Longitudinal ultrasonic dimensions and parametric solid models of the gravid uterus and cervix
Authors: Louwagie Erin Marie , Carlson Lindsey , Over Veronica , Mao Lu , Fang Shuyang , Westervelt Andrea , Vink Joy , Hall Timothy , Feltovich Helen , Myers Kristin
Published: January 2021

Tissue mechanics is central to pregnancy, during which maternal anatomic structures undergo continuous remodeling to serve a dual function to first protect the fetus in utero while it develops and then facilitate its passage out. In this study of normal pregnancy using biomechanical solid modeling, we used standard clinical ultrasound images to obtain measurements of structural dimensions of the gravid uterus and cervix throughout gestation. 2-dimensional ultrasound images were acquired from the uterus and cervix in 30 pregnant subjects in supine and standing positions at four time points during pregnancy (8-14, 14-16, 22-24, and 32-34 weeks). Offline, three observers independently measured from the images of multiple anatomic regions. Statistical analysis was performed to evaluate inter-observer variance, as well as effect of gestational age, gravity, and parity on maternal geometry. A parametric solid model developed in the Solidworks computer aided design (CAD) software was used to convert ultrasonic measurements to a 3-dimensional solid computer model, from which estimates of uterine and cervical volumes were made. This parametric model was compared against previous 3-dimensional solid models derived from magnetic resonance frequency images in pregnancy. In brief, we found several anatomic measurements easily derived from standard clinical imaging are reproducible and reliable, and provide sufficient information to allow biomechanical solid modeling. This structural dataset is the first, to our knowledge, to provide key variables to enable future computational calculations of tissue stress and stretch in pregnancy, making it possible to characterize the biomechanical milieu of normal pregnancy. This vital dataset will be the foundation to understand how the uterus and cervix malfunction in pregnancy leading to adverse perinatal outcomes.
Comparison of different cardiovascular risk tools used in HIV patient cohorts in sub-Saharan Africa; do we need to include laboratory tests?
Authors: Mubiru Frank , Castelnuovo Barbara , Reynolds Steven J. , Kiragga Agnes , Tibakabikoba Harriet , Owarwo Noela Clara , Kambugu Andrew , Lamorde Mohammed , Parkes-Ratanshi Rosalind
Published: January 2021

Introduction

Cardiovascular disease (CVD) is the leading cause of death globally, representing 31% of all global deaths. HIV and long term anti-retroviral therapy (ART) are risk factors for development of CVD in populations of people living with HIV (PLHIV). CVD risk assessment tools are currently being applied to SSA populations, but there are questions about accuracy as well as implementation challenges of these tools in lower resource setting populations. We aimed to assess the level of agreement between the various cardiovascular screening tools (Data collection on Adverse effects of anti-HIV Drugs (D:A:D), Framingham risk score, WHO risk score and The Atherosclerotic Cardiovascular Disease Score) when applied to an HIV ART experienced population in Sub-Saharan Africa.

Methods

This study was undertaken in an Anti-Retroviral Long Term (ALT) Cohort of 1000 PLHIV in care who have been on ART for at least 10 years in urban Uganda. A systematic review was undertaken to find the most frequently used screening tools from SSA PLHIV populations; these were applied to the ALT cohort. Levels of agreement between the resulting scores (those including lipids and non-lipids based, as well as HIV-specific and non-HIV specific) as applied to our cohort were compared. Prevalence Bias Adjusted Kappa was used to evaluate agreement between tools.

Results

Overall, PLHIV in ALT cohort had a median score of 1.1–1.4% risk of a CVD event over 5 years and 1.7–2.5% risk of a CVD event over 10 years. There was no statistical difference in the risk scores obtained for this population when comparing the different tools, including comparisons of those with lipids and non-lipids, and HIV specific vs non-HIV specific.

Conclusion

The various tools yielded similar results, but those not including lipids are more feasible to apply in our setting. Long-term cohorts of PLHIV in SSA should in future provide longitudinal data to evaluate existing CVD risk prediction tools for these populations. Inclusion of HIV and ART history factors to existing scoring systems may improve accuracy without adding the expense and technical difficulty of lipid testing.
How social preferences provide effort incentives in situations of financial support
Authors: Knoller Christian , Neuß Stefan , Peter Richard
Published: January 2021

When people anticipate financial support, they may reduce preventive effort. We conjecture that the source of financial support can mitigate this moral hazard effect due to social preferences. We compare effort choices when another individual voluntarily provides financial support against effort choices under purely monetary incentives. When financial support is provided voluntarily by another individual, we expect recipients to exert more effort to avoid bad outcomes (level effect) and to reduce effort provision to a lesser degree as financial support becomes more generous (sensitivity effect). We conducted an incentivized laboratory experiment and find some evidence for the level effect and strong evidence for the sensitivity effect. This leads to significant gains in material efficiency with expected wealth being 5.5% higher and 37.3% less volatile.
Ocean acidification decreases grazing pressure but alters morphological structure in a dominant coastal seaweed
Authors: Kinnby Alexandra , White Joel C. B. , Toth Gunilla B. , Pavia Henrik
Published: January 2021

Ocean acidification driven by anthropogenic climate change is causing a global decrease in pH, which is projected to be 0.4 units lower in coastal shallow waters by the year 2100. Previous studies have shown that seaweeds grown under such conditions may alter their growth and photosynthetic capacity. It is not clear how such alterations might impact interactions between seaweed and herbivores, e.g. through changes in feeding rates, nutritional value, or defense levels. Changes in seaweeds are particularly important for coastal food webs, as they are key primary producers and often habitat-forming species. We cultured the habitat-forming brown seaweed Fucus vesiculosus for 30 days in projected future pCO2 (1100 μatm) with genetically identical controls in ambient pCO2 (400 μatm). Thereafter the macroalgae were exposed to grazing by Littorina littorea, acclimated to the relevant pCO2-treatment. We found increased growth (measured as surface area increase), decreased tissue strength in a tensile strength test, and decreased chemical defense (phlorotannins) levels in seaweeds exposed to high pCO2-levels. The herbivores exposed to elevated pCO2-levels showed improved condition index, decreased consumption, but no significant change in feeding preference. Fucoid seaweeds such as F. vesiculosus play important ecological roles in coastal habitats and are often foundation species, with a key role for ecosystem structure and function. The change in surface area and associated decrease in breaking force, as demonstrated by our results, indicate that F. vesiculosus grown under elevated levels of pCO2 may acquire an altered morphology and reduced tissue strength. This, together with increased wave energy in coastal ecosystems due to climate change, could have detrimental effects by reducing both habitat and food availability for herbivores.
Household food sources and diarrhoea incidence in poor urban communities, Accra Ghana
Authors: Larbi Reuben Tete , Atiglo D. Yaw , Peterson Maame B. , Biney Adriana A. E. , Dodoo Naa Dodua , Dodoo F. Nii-Amoo
Published: January 2021

Diarrhoeal diseases remain a significant cause of morbidity and mortality, particularly in poor urban communities in the Global South. Studies on food access and safety have however not considered the sources of discrete food categories and their propensity to harbour and transmit diarrhoeal disease pathogens in poor urban settings. We sought to contribute to knowledge on urban food environment and enteric infections by interrogating the sources and categories of common foods and their tendency to transmit diarrhoea in low-income communities in Accra. We modelled the likelihood of diarrhoea transmission through specific food categories sourced from home or out of home after controlling for alternate transmission pathways and barriers. We used structured interviews where households that participated in the study were selected through a multi-stage systematic sampling approach. We utilized data on 506 households from 3 low-income settlements in Accra. These settlements have socio-economic characteristics mimicking typical low-income communities in the Global South. The results showed that the incidence of diarrhoea in a household is explained by type and source of food, source of drinking water, wealth and the presence of children below five years in the household. Rice-based staples which were consumed by 94.5% of respondents in the week preceding the survey had a higher likelihood of transmitting diarrhoeal diseases when consumed out of home than when eaten at home. Sources of hand-served dumpling-type foods categorized as “staple balls” had a nuanced relationship with incidence of diarrhoea. These findings reinforce the need for due diligence in addressing peculiar needs of people in vulnerable conditions of food environment in poor urban settlements in order to reap a co-benefit of reduced incidence of diarrhoea while striving to achieve the global development goal on ending hunger.
A measure of centrality in cyclic diffusion processes: Walk-betweenness
Authors: Youm Yoosik , Lee Byungkyu , Kim Junsol
Published: January 2021

Unlike many traditional measures of centrality based onpathsthat do not allow any repeated nodes or lines, we propose a new measure of centrality based onwalks,walk-betweenness, that allows any number of repeated nodes or lines. To illustrate the value of walk-betweenness, we examine the transmission of syphilis in Chicago area and the diffusion of microfinance in 43 rural Indian villages. Walk-betweenness allows us to identify hidden bridging communities in Chicago that were essential in the transmission dynamics. We also find that village leaders with high walk-betweenness are more likely to accelerate the rate of microfinance take-up among their followers, outperforming other traditional centrality measures in regression analyses.
Association between depressive symptoms and objective/subjective socioeconomic status among older adults of two regions in Myanmar
Authors: Sasaki Yuri , Shobugawa Yugo , Nozaki Ikuma , Takagi Daisuke , Nagamine Yuiko , Funato Masafumi , Chihara Yuki , Shirakura Yuki , Lwin Kay Thi , Zin Poe Ei , Bo Thae Zarchi , Sone Tomofumi , Win Hla Hla
Published: January 2021

Low objective socioeconomic status (SES) has been correlated with poor physical and mental health among older adults. Some studies suggest that subjective SES is also important for ensuring sound physical and mental health among older adults. However, few studies have been conducted on the impact of both objective and subjective SES on mental health among older adults. This study examines whether objective or subjective SES is associated with depressive symptoms in older adults in Myanmar. This cross-sectional study, conducted between September and December, 2018, used a multistage sampling method to recruit participants from two regions of Myanmar, for face-to-face interviews. The Geriatric Depression Scale (GDS) was used to evaluate the depressive symptoms. Participants were classified as having no depressive symptom (GDS score <5) and having depressive symptoms (GDS score ≥5). Objective and subjective SES were assessed using the wealth index and asking participants a multiple-choice question about their current financial situation, respectively. The relationship between objective/subjective SES and depressive symptoms was examined using a multivariable logistic regression analysis. The mean age of the 1,186 participants aged 60 years and above was 69.7 (SD: 7.3), and 706 (59.5%) were female. Among them, 265 (22.3%) had depressive symptoms. After adjusting for objective SES and other covariates, only low subjective SES was positively associated with depressive symptoms (adjusted odds ratio, AOR: 4.18, 95% confidence interval, CI: 2.98–5.87). This association was stronger among participants in the rural areas (urban areas, AOR: 2.10, 95% CI: 1.08–4.05; rural areas, AOR: 5.65, 95% CI: 3.69–8.64). Subjective SES has a stronger association with depressive symptoms than objective SES, among older adults of the two regions in Myanmar, especially in the rural areas. Interventions for depression in older adults should consider regional differences in the context of subjective SES by reducing socioeconomic disparities among the communities.
A cluster randomised trial of a Needs Assessment Tool for adult Cancer patients and their carers (NAT-C) in primary care: A feasibility study
Authors: Clark Joseph , Amoakwa Elvis , Wright-Hughes Alexandra , Blenkinsopp John , Currow David C. , Meads David , Farrin Amanda , Allgar Victoria , Macleod Una , Johnson Miriam
Published: January 2021

Background

People with cancer often have unidentified symptoms and social care needs. The Needs Assessment Tool-Cancer (NAT-C) is a validated, structured method of assessing patient/carer concerns and prompting action, to address unmet need.

Aims

Assess feasibility and acceptability of a definitive two-armed cluster randomised trial of NAT-C in primary care by evaluating: recruitment of GP practices, patients and carers; most effective approach of ensuring NAT-C appointments, acceptability of study measures and follow-up.

Methods

Non-blinded, feasibility study in four General Practices, with cluster randomisation to method of NAT-C appointment delivery, and process evaluation. Adults with active cancer were invited to participate with or without carer. Practices cluster randomised (1:1) to Arm I: promotion and use of NAT-C with a NAT-C trained clinician or Arm II: clinician of choice irrespective of training status. Participants completed study questionnaires at: baseline, 1, 3 and 6 months. Patients booked a 20 minute needs-assessment appointment post-baseline. Patients, carers and GP practice staff views regarding the study sought through interviews/focus groups. Quantitative data were analysed descriptively. Qualitative data were analysed thematically, informed by Normalisation Process Theory. Progression to a definitive trial was assessed against feasibility outcomes, relating to: recruitment rate, uptake and delivery of the NAT-C, data collection and quality.

Results

Five GP practices approached, four recruited and trained to use the NAT-C. Forty-seven participants and 17 carers recruited. At baseline, 34/47 (72%) participants reported at least one moderate-severe unmet need, confirming study rationale. 32/47 (68%) participants received a NAT-C-guided consultation, 19 of which on Arm I. Study attrition at one month (n = 44 (94%), n = 16 (94%)), three months (n = 38 (81%), n = 14 (82%)) and six months (n = 32 (68%), n = 10 (59%)). Fifteen patient interviews conducted across the whole study and one focus group at each GP practice. Participants supported a definitive study and found measures acceptable.

Conclusion

The feasibility trial indicated that recruitment rate, intervention uptake and data collection were appropriate, with refinements, for a definitive multi-centre cluster randomised controlled trial. Feasibility outcomes informed the design of a 2-armed cluster randomised controlled trial to test the effectiveness and cost-effectiveness of the NAT-C compared with usual care.
Brain organoid formation on decellularized porcine brain ECM hydrogels
Authors: Simsa Robin , Rothenbücher Theresa , Gürbüz Hakan , Ghosheh Nidal , Emneus Jenny , Jenndahl Lachmi , Kaplan David L. , Bergh Niklas , Serrano Alberto Martinez , Fogelstrand Per
Published: January 2021

Human brain tissue models such as cerebral organoids are essential tools for developmental and biomedical research. Current methods to generate cerebral organoids often utilize Matrigel as an external scaffold to provide structure and biologically relevant signals. Matrigel however is a nonspecific hydrogel of mouse tumor origin and does not represent the complexity of the brain protein environment. In this study, we investigated the application of a decellularized adult porcine brain extracellular matrix (B-ECM) which could be processed into a hydrogel (B-ECM hydrogel) to be used as a scaffold for human embryonic stem cell (hESC)-derived brain organoids. We decellularized pig brains with a novel detergent- and enzyme-based method and analyzed the biomaterial properties, including protein composition and content, DNA content, mechanical characteristics, surface structure, and antigen presence. Then, we compared the growth of human brain organoid models with the B-ECM hydrogel or Matrigel controlsin vitro. We found that the native brain source material was successfully decellularized with little remaining DNA content, while Mass Spectrometry (MS) showed the loss of several brain-specific proteins, while mainly different collagen types remained in the B-ECM. Rheological results revealed stable hydrogel formation, starting from B-ECM hydrogel concentrations of 5 mg/mL. hESCs cultured in B-ECM hydrogels showed gene expression and differentiation outcomes similar to those grown in Matrigel. These results indicate that B-ECM hydrogels can be used as an alternative scaffold for human cerebral organoid formation, and may be further optimized for improved organoid growth by further improving protein retention other than collagen after decellularization.
Evaluation of the practicability of a finger-stick whole-blood SARS-Cov-2 self-test adapted for the general population
Authors: Prazuck Thierry , Phan Van Jean , Sinturel Florence , Levray Frederique , Elie Allan , Camera Denise , Pialoux Gilles
Published: January 2021

Background

COVID-19 (COronaVIrus Disease 2019) is an infectious respiratory disease caused by the novel SARS-CoV-2 virus. Point of Care (POC) tests have been developed to detect specific antibodies, IgG and IgM, to SARS-CoV-2 virus in human whole blood. They need to be easily usable by the general population in order to alleviate the lockdown that many countries have initiated in response to the growing COVID-19 pandemic. A real-life study has been conducted in order to evaluate the performance of the COVID-PRESTO® POC test and the results were recently published. Even if this test showed very high sensitivity and specificity in a laboratory setting when used by trained professionals, it needs to be further evaluated for practicability when used by the general public in order to be approved by health authorities for in-home use.

Methods

143 participants were recruited between March 2020 and April 2020 among non-medical populations in central France (nuclear plant workers, individuals attending the Orleans University Hospital vaccination clinic and Orleans University Hospital non-medical staff). Instructions for use, with or without a tutorial video, were made available to the volunteers. Two separate objectives were pursued: evaluation of the capability of participants to obtain an interpretable result, and evaluation of the users’ ability to read the results.

Results

88.4% of the test users judged the instructions for use leaflet to be clear and understandable. 99.3% of the users obtained a valid result and, according to the supervisors, 92.7% of the tests were properly performed by the users. Overall, 95% of the users gave positive feedback on the COVID PRESTO® as a potential self-test. Neither age nor education had an influence.

Conclusion

COVID-PRESTO® was successfully used by an overwhelming majority of participants and its use was judged very satisfactory, therefore showing promising potential as a self-test to be used by the general population. This POC test can become an easy-to-use tool to help detect whether individuals are protected or not, particularly in the context of a second wave or a mass vaccination program.
Parental migration and psychological well-being of left-behind adolescents in Western Nepal
Authors: Kharel Madhu , Akira Shibanuma , Kiriya Junko , Ong Ken Ing Cherng , Jimba Masamine
Published: January 2021

Introduction

International migration is increasing rapidly around the world mostly to obtain a job. International migrant workers usually leave their children back in their country of origin, and among family members, adolescents may experience greater psychological distress from parental separation. However, limited evidence is available on the relationship between parental international migration and psychological well-being of left-behind adolescents. Nepal has a relatively higher and increasing number of international migrants, and this study was conducted to examine the association between parental international migration and the psychological well-being of left-behind adolescents in Nepal.

Methods

A school-based cross-sectional study was conducted among 626 adolescents in two districts of Western Nepal, where international migration is common. Adolescents were recruited through random sampling. Pre-tested “Strengths and Difficulties Questionnaire” was used to measure their psychological well-being and simple and multiple linear regression were used to examine the association between parental international migration and the psychological well-being of left-behind adolescents.

Results

Adolescents with none of the parents living abroad were more likely to have higher total difficulties score compared to those with one of the parents living abroad (B: 1.02; 95% CI: 0.18, 1.86; p = 0.017). Adolescents with the following factors were more likely to have higher total difficulties score in comparison to their counterparts: adolescents in their late adolescence period, female adolescents, adolescents from ethnicities other than Brahmin and adolescents studying in private schools.

Conclusion

In rural districts of Nepal, where international migration is common, adolescents living with the parents were more likely to have poorer psychological well-being compared to those with one of the parents living abroad. Adolescents’ adaptation mechanism for the absence of parents for international migration might be explored in the future studies.