bluuebunny/crossref_metadata_2025 huggingface dataset:
In vivohomopropargylglycine incorporation enables nascent protein tagging, isolation and characterisation fromArabidopsis thaliana
Authors: Tivendale Nathan D. , Fenske Ricarda , Duncan Owen , Millar A. Harvey
Published: March 2021

Determining which proteins are actively synthesised at a given point in time and extracting them for analysis is important to understand plant responses. Here we show that the methionine (Met) analogue homopropargylglycine (HPG) enables BONCAT (Bio-Orthogonal Non-Canonical Amino acid Tagging) of proteins being synthesised in Arabidopsis plants or cell cultures, facilitating their click-chemistry enrichment for analysis. The sites of HPG incorporation could be confirmed by peptide mass spectrometry at Met-sites throughout protein AA sequences and correlation with independent studies of protein labelling with15N verified the data. We provide evidence that HPG-based BONCAT tags nascent plant proteins more efficiently than azidohomoalanine (AHA)-based BONCAT in Arabidopsis and show that AHA’s induction of Met metabolism and greater inhibition of cell growth rate than HPG likely limits AHA incorporation at Met sites in Arabidopsis. We show HPG-based BONCAT provides a verifiable method for determining which plant proteins are being synthesised at a given time point and enriches new protein molecules from the bulk protein pool for identification, quantitation and subsequent biochemical analysis. Enriched nascent polypeptides were found to contain significantly fewer common post-translationally modified residues than the same proteins from whole plant extracts, providing evidence for age-related accumulation of PTMs in plants.
TAFKAP: An improved method for probabilistic decoding of cortical activity
Authors: van Bergen R.S. , Jehee J.F.M.
Published: March 2021

Cortical activity can be difficult to interpret. Neural responses to the same stimulus vary between presentations, due to random noise and other sources of variability. This unreliable relationship to external stimuli renders any pattern of activity open to a multitude of plausible interpretations. We have previously shown that this uncertainty in cortical stimulus representations can be characterized using a probabilistic decoding algorithm, which inverts a generative model of stimulus-evoked cortical responses. Here, we improve upon this method in two important ways, which both target the precision with which the generative model can be estimated from limited, noisy training data. We show that these improvements lead to considerably better estimation of the presented stimulus and its associated uncertainty. Estimates of the presented stimulus are recovered with an accuracy that exceeds that of standard decoding methods (SVMs), and in some cases even approaches the behavioral accuracy of human observers. Moreover, the uncertainty in the decoded probability distributions better characterizes the precision of cortical stimulus information from trial to trial.
Preoptic BRS3 neurons increase body temperature and heart rate via multiple pathways
Authors: Piñol Ramón A. , Mogul Allison S. , Hadley Colleen K. , Saha Atreyi , Li Chia , Škop Vojtěch , Province Haley S. , Xiao Cuiying , Gavrilova Oksana , Krashes Michael J. , Reitman Marc L.
Published: March 2021

The preoptic area (POA) is a key region controlling body temperature (Tb), dictating thermogenic, cardiovascular, and behavioral responses to regulate Tb. Known POA neuronal populations reduce Tb when activated; a population that increases Tb upon activation has not yet been reported. We now identify bombesin-like receptor 3 (BRS3)-expressing POA (POABRS3) neurons as having this missing functionality. BRS3 is an orphan receptor that regulates energy and cardiovascular homeostasis, but the relevant neural circuits are incompletely understood. In mice, we demonstrate that POABRS3neuronal activation increases Tb, heart rate, and blood pressure sympathetically, via projections to the paraventricular nucleus of the hypothalamus and dorsomedial hypothalamus. Acute POABRS3inhibition reduces Tb. Long-term inactivation of POABRS3neurons increased Tb variability with exaggerated Tb changes, overshooting both increases and decreases in Tb set point. BRS3 marks preoptic populations that regulate Tb and heart rate, contribute to cold-defense and fine-tune feedback control of Tb. These findings advance understanding of homeothermy, a defining feature of mammalian biology.

Graphical abstract
Diversity of an uncommon elastic hypersaline microbial mat along a small-scale transect
Authors: Espinosa-Asuar Laura , Monroy-Guzmán Camila , Madrigal-Trejo David , Navarro-Miranda Marisol , Sánchez-Pérez Jazmin , Buenrostro-Muñoz Jhoselinne , Villar Juan , Cifuentes Camargo Julián Felipe , Kalambokidis Maria , Esquivel-Hernandez Diego A. , Jasso Mariette Viladomat , Escalante Ana E. , Velez Patricia , Figueroa Mario , Cárdenas Anahí Martínez , Barahona Santiago Ramirez , Gasca-Pineda Jaime , Eguiarte Luis E. , Souza Valeria
Published: March 2021

We evaluated the microbial diversity and metabolome profile of an uncommon hypersaline elastic microbial mat from Cuatro Ciénegas Basin (CCB) in the Chihuahuan Desert of Coahuila, México. We collected ten samples on a small scale transect (1.5-meters) and described its microbial diversity through NGS-based ITS and 16S rDNA gene sequencing. A very low number of taxa comprised a considerable proportion of the mat and were shared across all sampling points, whereas the rare biosphere was more phylogenetically diverse (Faith’s Phylogenetic Diversity (FPD) index) and phylogenetically disperse (using a null model distribution of Phylogenetic Species Clustering (nmdPSC)) than the abundant (high read count) taxa for both analyzed libraries. We also found a distinctive metabolome profile for each sample and were able to tentatively annotate several classes of compounds with relevant biological properties.
DNA supercoiling-mediated collective behavior of co-transcribing RNA polymerases
Authors: Tripathi Shubham , Brahmachari Sumitabha , Onuchic José N. , Levine Herbert
Published: March 2021

Multiple RNA polymerases (RNAPs) transcribing a gene have been known to exhibit collective group behavior, causing the transcription elongation rate to increase with the rate of transcription initiation. Such behavior has long been believed to be driven by a physical interaction or “push” between closely spaced RNAPs. However, recent studies have posited that RNAPs separated by longer distances may cooperate via the DNA segment under transcription. Here, we present a theoretical model incorporating the mechanical coupling between RNAP translocation and the torsional response of supercoiled DNA. Using stochastic simulations, we demonstrate long-range cooperation between co-transcribing RNAPs mediated by DNA supercoiling. We find that inhibiting transcription initiation can slow down the already recruited RNAPs, in agreement with recent experimental observations, and predict that the average transcription elongation rate varies non-monotonically with the rate of transcription initiation. We further show that while RNAPs transcribing neighboring genes oriented in tandem can cooperate, those transcribing genes in divergent or convergent orientations can act antagonistically, and that such behavior holds over a large range of intergenic separations. Our model makes testable predictions, revealing how the mechanical interplay between RNAPs and the DNA they transcribe can govern a key cellular process.
Zoonotic spillover of SARS-CoV-2: mink-adapted virus in humans
Authors: Rabalski Lukasz , Kosinski Maciej , Mazur-Panasiuk Natalia , Szewczyk Boguslaw , Bienkowska-Szewczyk Krystyna , Kant Ravi , Sironen Tarja , Pyrć Krysztof , Grzybek Maciej
Published: March 2021

The COVID-19 pandemic caused by SARS-CoV-2 started in fall 2019. A range of different mammalian species, including farmed mink, have been confirmed as susceptible to infection with this virus. We report here the spillover of mink-adapted SARS-CoV-2 from farmed mink to humans after extensive adaptation that lasted at least 3 months. We found the presence of four mutations in the S gene (that gave rise to variant: G75V, M177T, Y453F and C1247F) and others in an isolate obtained from SARS-CoV-2 positive patient.
Unmanned aircraft automatic flight control algorithm in an Immelmann manoeuvre
Authors: Rogalski Tomasz , Rzucidło Paweł , Noga Stanisław , Prusik Jacek
Published: March 2021

Purpose

The purpose of this paper is to present the idea of automatic flight control algorithms capable of performing an Immelmann turn manoeuvre automatically. This is a case of a manoeuvre far removed from so-called standard flight. The character of this manoeuvre and the range of changes in the aircraft flight parameters restrict the application of standard control algorithms. Furthermore, the possibility of acquiring full and detailed information about the aircraft’s flight parameters is limited in such cases. This paper seeks to analyse an alternative solution that can be applied in some specific cases.

Design/methodology/approach

This paper uses theoretical discussion and breakdowns to create the basics for development of structures of control algorithms. A simplified analytical approach was applied to tune regulators and the results of the research were verified in a series of software-in-the loop computer simulations.

Findings

The structure of the control system enabling aerobatic flight (with the Immelmann turn as the selected example) was identified and the method for tuning the regulators is also presented.

Practical implications

It could serve as a foundation for autopilots working in non-conventional flight states and aircraft automatic recovery systems.

Originality/value

This paper presents the author’s original approach to aircraft automatic control when high control precision is not the priority and not all flight parameters can be precisely measured.
Introduction of new Picard–S hybrid iteration with application and some results for nonexpansive mappings
Authors: Srivastava Julee
Published: March 2021

Purpose

In this paper, Picard–S hybrid iterative process is defined, which is a hybrid of Picard and S-iterative process. This new iteration converges faster than all of Picard, Krasnoselskii, Mann, Ishikawa, S-iteration, Picard–Mann hybrid, Picard–Krasnoselskii hybrid and Picard–Ishikawa hybrid iterative processes for contraction mappings and to find the solution of delay differential equation, using this hybrid iteration also proved some results for Picard–S hybrid iterative process for nonexpansive mappings.

Design/methodology/approach

This new iteration converges faster than all of Picard, Krasnoselskii, Mann, Ishikawa, S-iteration, Picard–Mann hybrid, Picard–Krasnoselskii hybrid, Picard–Ishikawa hybrid iterative processes for contraction mappings.

Findings

Showed the fastest convergence of this new iteration and then other iteration defined in this paper. The author finds the solution of delay differential equation using this hybrid iteration. For new iteration, the author also proved a theorem for nonexpansive mapping.

Originality/value

This new iteration converges faster than all of Picard, Krasnoselskii, Mann, Ishikawa, S-iteration, Picard–Mann hybrid, Picard–Krasnoselskii hybrid, Picard–Ishikawa hybrid iterative processes for contraction mappings and to find the solution of delay differential equation, using this hybrid iteration also proved some results for Picard–S hybrid iterative process for nonexpansive mappings.
Moving theory focus beyond individuals targeted for change: observing project stakeholder interactions
Authors: Roemer Carina , Rundle-Thiele Sharyn , David Patricia
Published: March 2021

Purpose

Social marketing theories have habituated to a theoretical and methodological focus that is criticised for being myopic and stigmatising. Following recommendations to redirect focus theoretically, the purpose of this paper is to apply an observational methodology to understanding how project stakeholders interact to examine whether consideration of stakeholders can identify factors facilitating or impeding farming practice change.

Design/methodology/approach

More than 48 events involving as many as 150 people including project stakeholder meetings, one-on-one consultations and annual events were observed over more than 100 h by between one and five researchers. Field notes were gathered, and thematic coding focussed on understanding how stakeholders facilitated or impeded practice change.

Findings

Observations identified limited provision of information about the project by on ground project stakeholders to targeted individuals (farmers). On the rare occasions where information sharing was observed, communication was delayed making it difficult for individuals to connect actions with outcomes observed. Participating stakeholders did not freely support delivery of activities needed for individual practice change.

Practical implications

This study indicates the value of wider process and outcome assessment encompassing stakeholders to identify factors impeding and facilitating farming practice change.

Social implications

Approaches that centre attention on individuals fail to acknowledge the inputs, activities and outputs delivered by project stakeholders within a system of change. By redirecting evaluation focus, shared responsibility is gained and stigmatisation of one stakeholder group can be avoided.

Originality/value

This study demonstrates how observations can be used to redirect focus to consider actions and interactions occurring between on ground project stakeholders. A stakeholder evaluation approach extends monitoring and evaluation focus beyond individuals targeted for behaviour change. Implications, limitations and future research directions are outlined.
Different population trajectories of two reef‐building corals with similar life‐history traits
Authors: Shlesinger Tom , van Woesik Robert
Published: March 2021

Increases in the frequency and intensity of acute and chronic disturbances are causing declines of coral reefs world‐wide. Although quantifying the responses of corals to acute disturbances is well documented, detecting subtle responses of coral populations to chronic disturbances is less common, but can also result in altered population and community structures.

We investigated the population dynamics of two key reef‐building Merulinid coral species, Dipsastraea favus and Platygyra lamellina, with similar life‐history traits, in the Gulf of Eilat and Aqaba, Red Sea from 2015 to 2018, to assess potential differences in their population trajectories.

Demographic processes, which included rates of survival, growth, reproduction and recruitment were used to parametrize integral projection models and estimate population growth rates and the likely population trajectories of both coral species.

The survival and reproduction rates of both D. favus and P. lamellina were positively related to coral colony size, and elasticity analyses showed that large colonies most influenced population dynamics. Although both species have similar life‐history traits and growth morphologies and are generally regarded as ‘stress‐tolerant’, the populations showed contrasting trajectories—D. favus appears to be increasing whereas P. lamellina appears to be decreasing.

As many corals have long‐life expectancies, the process of local and regional decline might be subtle and slow. Ecological assessments based on total living coral coverage, morphological groups or functional traits might overlook subtle, species‐specific trends. However, demographic approaches capable of detecting subtle species‐specific population changes can augment ecological studies and provide valuable early warning signs of decline before major coral loss becomes evident.
Asymmetric foraging lowers the trophic level and omnivory in natural food webs
Authors: Zheng Junjie , Brose Ulrich , Gravel Dominique , Gauzens Benoit , Luo Mingyu , Wang Shaopeng
Published: March 2021

Food webs capture the trophic relationships and energy fluxes between species, which has fundamental impacts on ecosystem functioning and stability. Within a food web, the energy flux distribution between a predator and its prey species is shaped by food quantity–quality trade‐offs and the contiguity of foraging. But the distribution of energy fluxes among prey species as well as its drivers and implications remain unclear.

Here we used 157 aquatic food webs, which contain explicit energy flux information, to examine whether a predator's foraging is asymmetric and biased towards lower or higher trophic levels, and how these patterns may change with trophic level. We also evaluate how traditional topology‐based approaches may over‐ or under‐estimate a predator's trophic level and omnivory by ignoring the asymmetric foraging patterns.

Our results demonstrated the prevalence of asymmetric foraging in natural aquatic food webs. Although predators prefer prey at higher trophic levels with potentially higher food quality, they obtain their energy mostly from lower trophic levels with a higher food quantity. Both tendencies, that is, stronger feeding preference for prey at higher trophic levels and stronger energetic reliance on prey at lower trophic levels are alleviated for predators at higher trophic levels.

The asymmetric foraging lowers trophic levels and omnivory at both species and food web levels, compared to estimates from traditional topology‐based approaches. Such overestimations by topology‐based approaches are most pronounced for predators at lower trophic levels and communities with higher number of trophic species.

Our study highlights the importance of energy flux information in understanding the foraging behaviour of predators as well as the structural complexity of natural food webs. The increasing availability of flux‐based food web data will thus provide new opportunities to reconcile food web structure, functioning and stability.
Histological sequence of the development of rat mesothelioma by MWCNT, with the involvement of apolipoproteins
Authors: Hojo Motoki , Yamamoto Yukio , Sakamoto Yoshimitsu , Maeno Ai , Ohnuki Aya , Suzuki Jin , Inomata Akiko , Moriyasu Takako , Taquahashi Yuhji , Kanno Jun , Hirose Akihiko , Nakae Dai
Published: March 2021

A rat model of mesothelioma development by peritoneal injection of multiwalled carbon nanotube (MWCNT) has been established and found to be useful to understand the mechanisms underlying fibrous particles‐associated carcinogenesis. Its detailed histological sequence, however, remains largely obscure. We therefore aimed to assess the time‐course of mesothelioma development by MWCNT and evaluate a set of lipoprotein‐related molecules as potential mechanism‐based biomarkers for the phenomenon. Male Fischer 344 rats were injected intraperitoneally (ip) with MWCNT (MWNT‐7) at 1 mg/kg body weight, and necropsied at 8, 16, 24, 32, or 42 wk after injection. For biochemical analyses of the lipoprotein‐related molecules, more samples, including severe mesothelioma cases, were obtained from 2 other carcinogenicity tests. Histologically, in association with chronic inflammation, mesothelial proliferative lesions appeared at c. Wk‐24. Before and at the beginning of the tumor development, a prominent infiltration of CD163‐positive cells was seen near mesothelial cells. The histological pattern of early mesothelioma was not a papillary structure, but was a characteristic structure with a spherical appearance, composed of the mesothelioma cells in the surface area that were underlain by connective tissue‐like cells. Along with the progression, mesotheliomas started to show versatile histological subtypes. Serum levels of apolipoprotein A‐I and A‐IV, and a ratio of HDL cholesterol to total cholesterol were inversely correlated with mesothelioma severity. Overall, the detailed histological sequence of mesotheliomagenesis by MWCNT is demonstrated, and indicated that the altered profile of apolipoproteins may be involved in its underlying mechanisms.
Effectiveness and safety of zinc oxide nanoparticle‐coated socks compared to uncoated socks for the prevention of pitted keratolysis: a double‐blinded, randomized, controlled trial study
Authors: Ongsri Punyawee , Leeyaphan Charussri , Limphoka Pichaya , Kiratiwongwan Rungsima , Bunyaratavej Sumanas
Published: March 2021

Background

Pitted keratolysis (PK) and bromodosis have negative impacts on the quality of life especially for military personnel. The antibacterial efficacy and safety of zinc oxide nanoparticles (ZnO‐NPs) make them a suitable additive for textiles. We aim to establish the ability of ZnO‐NP‐coated socks to prevent PK and bromodosis in a real‐life setting.

Materials and methods

A double‐blinded, randomized, controlled trial was conducted in January 2019. Naval cadets assigned to a 14‐day field training course were randomly allocated to either a ZnO‐NP‐coated or an uncoated‐sock group. They completed questionnaires evaluating behavioral risk factors and self‐assessed foot odor levels using a visual analogue scale (VAS); intervention‐blinded dermatologists also performed foot examinations. They reassessed their odor levels and had their feet re‐examined upon completion of the training course.

Results

The 148 cadets enrolled for the study were allocated to two groups of 74 each. The ZnO‐NP‐coated sock participants demonstrated significantly less PK development than uncoated socks (P = 0.05). There was a reduction of the foot odor levels in both groups, as measured by the VAS, without statistical difference. However, the uncoated sock group experienced more foot odor with a significantly greater negative effect on their daily lives (P = 0.04) than the ZnO‐NP‐coated sock group.

Conclusions

ZnO‐NP‐coated socks proved their efficacy in inhibiting the development of PK for military personnel.
State‐of‐the‐art microscopy to understand islets of Langerhans: what to expect next?
Authors: de Boer Pascal , Giepmans Ben NG
Published: March 2021

The discovery of Langerhans and microscopic description of islets in the pancreas were crucial steps in the discovery of insulin. Over the past 150 years, many discoveries in islet biology and type 1 diabetes have been made using powerful microscopic techniques. In the past decade, combination of new probes, animal and tissue models, application of new biosensors and automation of light and electron microscopic methods and other (sub)cellular imaging modalities have proven their potential in understanding the beta cell under (patho)physiological conditions. The imaging evolution, from fluorescent jellyfish to real‐time intravital functional imaging, the revolution in automation and data handling and the increased resolving power of analytical imaging techniques are now converging. Here, we review innovative approaches that address islet biology from new angles by studying cells and molecules at high spatiotemporal resolution and in live models. Broad implementation of these cellular imaging techniques will shed new light on cause/consequence of (mal)function in islets of Langerhans in the years to come.
Derivation of the Structural Integrity of Residual (SIR) glass model for the enhancement of waste loading
Authors: McClane Devon L. , Amoroso Jake W. , Hsieh Madison C. , Fox Kevin M. , Kruger Albert A.
Published: March 2021

A new model based on glass structure to allow for enhanced waste loading in nuclear waste glass while maintaining chemical durability is proposed. The model is derived by splitting the molar concentrations of the targeted starting glass composition into theoretical crystalline phases anticipated to be observed during devitrification and a residual glass. An empirically derived relationship based on maintaining the residual glass structure, determined from a calculated non‐bridging oxygen content, was demonstrated to successfully screen glasses for acceptable durability. The proposed model can successfully identify durable glass compositions containing 20–35 wt% Al2O3, a concentration that would significantly increase the projected waste loading in glasses processed at the Hanford Tank Waste Treatment and Immobilization Plant.
Measuring Lawyer Well‐Being Systematically: Evidence from the National Health Interview Survey
Authors: Listokin Yair , Noonan Raymond
Published: March 2021

Conventional wisdom says that lawyers are uniquely unhappy. Unfortunately, this conventional wisdom rests on a weak empirical foundation. The “unhappy lawyers” narrative relies on nonrandom survey data collected from volunteer respondents. Instead of depending on such data, researchers should study lawyer mental health by relying on large microdatasets of public health data, such as the National Health Interview Survey (NHIS) administered by the U.S. Centers for Disease Control. The NHIS includes data from 100–200 lawyers per year. By aggregating years, an adequate sample size of lawyers can readily be obtained, with much greater confidence that the lawyers in the sample resemble the true population of U.S. lawyers. When we examine the NHIS data, we find that, contrary to the conventional wisdom, lawyers are not particularly unhappy. Indeed, they suffer rates of mental illness much lower than the general population. Lawyer mental health is not significantly different than the mental health of similarly educated professionals, such as doctors and dentists. Rates of problematic alcohol use among lawyers, however, are high, even when compared to the general population. Moreover, problematic use of alcohol among lawyers has grown increasingly common over the last 15 years. These sometimes surprising and nuanced findings demonstrate the value of relying on more reliable data such as the NHIS.
Snow depth and woody debris drive variation in small‐mammal winter seed removal
Authors: Guiden Peter W. , Orrock John L.
Published: March 2021

Aims

In temperate forests, small increases in winter temperature can lead to substantial decreases in snow accumulation, which may alter plant–consumer interactions such as seed predation. However, seed predation by small mammals may also be affected by local habitat structure (e.g., downed woody debris). We tested whether the effect of snow depth on seed predation by small mammals depends on habitat structure (woody debris) that may influence small‐mammal foraging behavior.

Location

Northern temperate forests in Wisconsin, USA.

Methods

We performed a factorial manipulation of snow depth and woody debris presence at 10 sites that differed in site‐level ambient woody debris. At these sites, we monitored seed removal of four temperate tree species (Abies balsamea, Acer rubrum, Acer saccharum, Pinus resinosa).

Results

Mean rates of winter seed removal varied among species, as did the effects of snow depth and woody debris. The presence of woody debris decreased Abies balsamea seed removal in plots with snow removed. Regardless of woody debris, snow removal increased Acer saccharum seed removal. Acer rubrum seed removal was lowest at sites with high site‐level woody debris volume, especially in plots with snow removed.

Conclusions

Warming winter temperatures may amplify seed removal for some tree species, but local‐scale heterogeneity in woody debris may modify these effects. Because the effects of woody debris and snow removal were much stronger for some tree species than others, changes in seed removal associated with reduced future snow cover or changes in forest management may accelerate regional changes in forest composition.
Feminist Critical Hindu Studies in formation
Authors:   FCHS Collective
Published: March 2021

This article outlines the philosophy, methodology, and aims of Feminist Critical Hindu Studies (FCHS). We propose a series of strategies and commitments for change and action in the fields of South Asian Religions, Hindu Studies, and South Asian Studies. We draw on the work of scholars in Queer, Critical Race, and Feminist theories. We argue for a queering methodology that disorients us from and seeks to make visible the structures of knowledge and power on which Hinduism and Hindu Studies rest, including the intersecting processes of racialization, the regulation of sexuality and gender, and the violence of caste. We use the concept of Hindu formations to complicate the notions of “Hinduism” and “Hindus” as categories that not only arise in conjunction with forms of white supremacy and caste supremacy, but are imbricated with them. This approach allows us to explore how these categories have been used by various groups throughout history to empower and subjugate people. Driven by the theoretical frameworks of disorientation, intersectionality, and assemblage, FCHS reorients us in our relationship to Hindu Studies, as well as the spaces, practices, and people that inhabit academic institutions, newly attentive to who and what is missing. The work of FCHS is both academic and activist in nature: we call for ethical commitments to build meaningful relations of solidarity and allyship. Working against systemic oppression requires a willingness to interrogate our own positionalities and challenge our complicities.
In vivo determination of the Infrared‐A protection factor on human skin
Authors: Kim Su Ji , Lee Hyo Jin , Lee Ji Hyun , Oh Heemuk , Park Saerom , Lim Doo Hyeon , Park Myeong Sam , Lee Jun Bae
Published: March 2021

Background

Chronic exposure to infrared A (IR‐A) irradiation causes photoaging. However, daily or acute exposure to IR‐A rarely induces erythema or pigmentation. Thus, evaluation of the physiological changes taking place on the skin surface is insufficient for clinical investigations.

Materials and methods

We fabricated a novel device to obtain the IR‐A protection factor (IPF) on human skin. This device consists of an artificial light source that mimics the actual IR‐A intensity of sunlight, and a spectrophotometer to measure the spectral reflectance on the skin surface. The IPF can be determined by measuring the difference in spectral reflectance on the skin before and after the use of products and can be verified by the statistical criterion. A validation study was performed using different light intensities and two experimenters. Finally, we monitored the IPF on 12 commercial cosmetics.

Results

After considering the IPF and L*‐values, we selected the optimal sample and performed a validation study. Neither the intensity of IR‐A irradiation or the experimenters significantly affected the IPF. 12 commercial products exhibited their own IPF values and were verified by statistical criteria, with one exception.

Conclusion

The present IPF evaluation method was concluded to be robust and reliable. This method is simple and safe for the subjects, and could be helpful for the development of IR‐A protection products and the confirmation of product performances.
Limited specificity of commercially available SARS‐CoV‐2 IgG ELISAs in serum samples of African origin
Authors: Emmerich Petra , Murawski Carolin , Ehmen Christa , von Possel Ronald , Pekarek Neele , Oestereich Lisa , Duraffour Sophie , Pahlmann Meike , Struck Nicole , Eibach Daniel , Krumkamp Ralf , Amuasi John , Maiga‐Ascofaré Oumou , Rakotozandrindrainy Raphael , Asogun Danny , Ighodalo Yemisi , Kann Simone , May Jürgen , Tannich Egbert , Deschermeier Christina
Published: March 2021

Objectives

Specific serological tests are mandatory for reliable SARS‐CoV‐2 diagnostics and seroprevalence studies. Here, we assess the specificities of four commercially available SARS‐CoV‐2 IgG ELISAs in serum/plasma panels originating from Africa, South America, and Europe.

Methods

882 serum/plasma samples collected from symptom‐free donors before the COVID‐19 pandemic in three African countries (Ghana, Madagascar, Nigeria), Colombia, and Germany were analysed with three nucleocapsid‐based ELISAs (Euroimmun Anti‐SARS‐CoV‐2‐NCP IgG, EDI™ Novel Coronavirus COVID‐19 IgG, Mikrogen recomWell SARS‐CoV‐2 IgG), one spike/S1‐based ELISA (Euroimmun Anti‐SARS‐CoV‐2 IgG), and in‐house common cold CoV ELISAs.

Results

High specificity was confirmed for all SARS‐CoV‐2 IgG ELISAs for Madagascan (93.4–99.4%), Colombian (97.8–100.0%), and German (95.9–100.0%) samples. In contrast, specificity was much lower for the Ghanaian and Nigerian serum panels (Ghana: NCP‐based assays 77.7–89.7%, spike/S1‐based assay 94.3%; Nigeria: NCP‐based assays 39.3–82.7%, spike/S1‐based assay 90.7%). 15 of 600 African sera were concordantly classified as positive in both the NCP‐based and the spike/S1‐based Euroimmun ELISA, but did not inhibit spike/ACE2 binding in a surrogate virus neutralisation test. IgG antibodies elicited by previous infections with common cold CoVs were found in all sample panels, including those from Madagascar, Colombia, and Germany and thus do not inevitably hamper assay specificity. Nevertheless, high levels of IgG antibodies interacting with OC43 NCP were found in all 15 SARS‐CoV‐2 NCP/spike/S1 ELISA positive sera.

Conclusions

Depending on the chosen antigen and assay protocol, SARS‐CoV‐2 IgG ELISA specificity may be significantly reduced in certain populations probably due to interference of immune responses to endemic pathogens like other viruses or parasites.
Food insecurity and depression: a cross‐sectional study of a multi‐site urban youth cohort in Durban and Soweto, South Africa
Authors: Jesson Julie , Dietrich Janan , Beksinska Mags , Closson Kalysha , Nduna Mzikazi , Smit Jenni , Brockman Mark , Ndung'u Thumbi , Gray Glenda , Kaida Angela
Published: March 2021

Objective

To assess the prevalence of food insecurity and the independent association between depression and food insecurity among youth living in two urban settings in South Africa.

Methods

Baseline cross‐sectional survey data was analysed from a prospective cohort study conducted between 2014 and 2016 among youth (aged 16–24 years) in Soweto and Durban. Interviewer‐administered questionnaires collecting socio‐demographic, sexual and reproductive health and mental health data were conducted. Household food insecurity was measured using the 3‐item Household Hunger Scale, with food insecure participants defined as having ‘moderate’ or ‘severe hunger’ compared to ‘no hunger’. Depression was assessed using the 10‐item Center for Epidemiological Studies Depression (CES‐D 10) Scale (range 0–30, probable depression ≥ 10). Multivariable logistic regression models were used to estimate the association between depression and food insecurity.

Results

There were 422 participants. Median age was 19 years (interquartile range [IQR] 18–21) and 60% were women. Overall, 18% were food insecure and 42% had probable depression. After adjustment for socio‐demographic variables (age, gender, female‐headed household, household size and school enrolment), participants with probable depression had higher odds of being food insecure than non‐depressed participants (2.79, 95%CI 1.57–4.94).

Conclusion

Nearly one‐fifth of youth in this study were food insecure. Those with probable depression had increased odds of food insecurity. Interventions are needed to address food insecurity among urban youth in South Africa, combining nutritional support and better access to quality food with mental health support.
Dévisser, découper, éclater et aplatir les espaces de Berkovich
Authors: Ducros Antoine
Published: March 2021

Nous développons dans cet article des techniques d'aplatissement des faisceaux cohérents en géométrie de Berkovich, en nous inspirant de la stratégie générale que Raynaud et Gruson ont mise en œuvre pour traiter le problème analogue en théorie des schémas. Nous donnons ensuite quelques applications à l’étude des morphismes entre espaces analytiques compacts, et obtenons notamment une description de l'image d'un tel morphisme.
A Method for Designing Ball Wheels for Omnidirectional Vehicles
Authors: West Mark , Asada Haruhiko
Published: March 2021

A method for designing ball wheel mechanisms for vehicles with omnidirectional motion capability is presented in this paper. A ball wheel mechanism holds a spherical tire while allowing it to rotate with two degrees of freedom such that it may roll in an arbitrary direction on the floor. This paper concerns a particular class of ball wheel mechanisms which hold a spherical tire in a special arrangement of rollers. Due to point contacts between these rollers and the tire, and between the tire and the ground, specific considerations are required to achieve large payload capacity and traction as well as high position control accuracy. First, we review the kinematic conditions for theoretical functionality of the class of ball wheels and describe a proof-of-concept prototype vehicle. Starting from the generalized ball wheel mechanism, we then identify a subset of designs that contains the optimal ball wheel mechanisms for most applications. Within this subset, the design is optimized by parameterizing the design space. By analyzing the phenomena relating the design parameters to three performance indices — payload capacity, acceleration and repeatability — a surface can found in the performance space that represents the maximum ball wheel performance for all permutations of the design parameters. This surface will be used by vehicle designers to evaluate ball wheel performance in comparison with other omnidirectional drive mechanisms. A simple lookup table can then be used to find the design parameter values which provide desired performance.
An Overview of Engineering Concepts and Current Design Algorithms for Probabilistic Structural Analysis
Authors: Duffy S. F. , Hu J. , Hopkins D. A.
Published: March 2021

The article begins by examining the fundamentals of traditional deterministic design philosophy. The initial section outlines the concepts of failure criteria and limit state functions, two traditional notions that are embedded in deterministic design philosophy. This is followed by a discussion regarding safety factors (a possible limit state function) and the common utilization of statistical concepts in deterministic engineering design approaches. Next, the fundamental aspects of a probabilistic failure analysis are explored, and it is shown that deterministic design concepts mentioned in the initial portion of the article are embedded in probabilistic design methods. For components fabricated from ceramic materials (and other similarly brittle materials) the probabilistic design approach yields the widely used Weibull analysis after suitable assumptions are incorporated. The authors point out that Weibull analysis provides the rare instance where closed form solutions are available for a probabilistic failure analysis. Since numerical methods are usually required to evaluate component reliabilities, a section on Monte Carlo methods is included to introduce the concept. The article concludes with a presentation of the technical aspects that support the numerical method known as fast probability integration (FPI). This includes a discussion of the Hasofer-Lind and Rackwitz-Fiessler approximations.
Combined-Mode Parametric Oscillations in Mechanical Systems
Authors: Sato Chikara
Published: March 2021

Parametric oscillations formulated by linear or nonlinear differential equations of order two are often encountered in the textbooks on the theory of nonlinear oscillations. Mathieu equation or its modified nonlinear version are seen in many papers as the typical examples. Parametric oscillations of the higher order than two, however, are less investigated, and the fundamental form is little known, especially the knowledge on the engineering viewpoint is little published in relation with mechanical or physical models.

This paper deals with the parametirc oscillations governed by periodic differential equations with the higher order than two, presenting the fundamental mathematical form with many physical, mechanical, and electrical examples. General nonlinear systems with parametric excitation are not easy to treat with, because they have many characters depending on the specific forms of the systems. In this paper we confine systems which have three conditions, first excitation frequency region is limited, second symmetry condition or reciprocity is kept, third no energy condition of nonlinear functions. These conditions are partly mathematical and partly physical. In order to treat with parametric oscillation we think that the causes of oscillations are only parametric instability. Without parametric excitation no significant oscillations are assumed to exist.
A Generalized Nonlinear Model for Active Magnetic Bearings
Authors: Gao Jianmin , Zhu Xiaomei , McCafferty Ray , Leighton Nigel
Published: March 2021

This paper describes a generalized nonlinear model of active magnetic bearings, for arbitrary number, size and position of pole-pairs, including the coordinate coupling between the vertical and horizontal directions, the nonlinearility of the power amplifier and the effect of finite permeability of the ferromagnetic bearing material. As an example, a practical magnetic bearing with four pole-pairs is examined. The predicted force from the model is quite consistent with experimental results. For the PD controller implemented for a horizontal rotor, the expectation of the equilibrium of the rotor also agrees quite well with the measurement.
Vibrations of a Cracked Rotor (3/2-Order Super-Subharmonic and 1/2-Order Subharmonic Resonances)
Authors: Ishida Yukio , Hirokawa Kazuharu , Hirose Mitsuo
Published: March 2021

When a transverse crack appears in a rotating horizontal shaft due to fatigue, various kinds of resonances occur. In this paper, the vibration characteristics of the 3/2-order super-subharmonic resonance and the 1/2-order subharmimic resonance are investigated. We represent the spring characteristics of a cracked shaft by a piecewise linear type nonlinearlity and approximate it by a power series. The following are clarified, (a) These two kinds of resonances have similar vibration characteristics, (b) They occur only in horizontal shafts, (c) Although they are related to the parametric excitation, they occur as the steady-state oscillations due to nonlinearlity. (d) The amplitudes of these steady-state oscillations decrease as the unbalance increases.
Occurrence of Combination Tones in a String
Authors: Yasuda Kimihiko , Kato Mitsuhiro
Published: March 2021

The occurrence of combination tones in a string subjected to two harmonic excitations is considered. Attention is focused on the case in which the sum or difference of the excitation frequencies is near one of the natural frequencies of the string. To analyze the problem, the method of multiple scales is used. In analyzing the problem it is taken into account that a string has its natural frequencies in the ratio of prime integers. 1 : 2 : 3 : ⋯. The analysis shows that, due to this, the combination tones with various characters can occur.
Melnikov-Based Open-Loop Control of Escape for a Class of Nonlinear Systems
Authors: Simiu Emil , Franaszek Marek
Published: March 2021

The performance of certain nonlinear stochastic systems is deemed acceptable if, during a specified time interval, the systems have sufficiently low probabilities of escape from a preferred region of phase space. We propose an open-loop control method for reducing these probabilities. The method is applicable to stochastic systems whose dissipation- and excitation-free counterparts have homoclinic or heteroclinic orbits. The Melnikov relative scale factors are system properties containing information on the frequencies of the random forcing spectral components that are most effective in inducing escapes. This information is useful in practice even if the dissipation and excitation terms are relatively large. An ideal open-loop control force applied to the system would be equal to the negative of a fraction of the exciting force from which the ineffective components have been filtered out. Limitations inherent in any practical control system make it impossible to achieve such an ideal control. Nevertheless, numerical simulations show that substantial advantages can be achieved in some cases by designing control systems that take into account the information contained in the Melnikov scale factors.
Simulation of Stochastic Processes and Fields for Monte Carlo Simulation Applications: Some Recent Developments
Authors: Deodatis George , Popescu Radu , Prevost Jean H.
Published: March 2021

Two of the latest developments concerning the spectral representation method (used to simulate stochastic processes and fields) are presented in this paper. The first one introduces an extension of the spectral representation method to simulate non-stationary stochastic vector processes with evolutionary power. The proposed simulation formula is simple and straightforward and generates sample functions of the vector process according to a prescribed non-stationary cross-spectral density matrix. The second development introduces another extension of the spectral representation method to simulate multi-dimensional, multi-variate, non-Gaussian stochastic fields. In this case, sample functions are generated according to a prescribed cross-spectral density matrix and prescribed (non-Gaussian) probability distribution functions. Numerical examples are provided for both developments.
Use of Directional AR and ML Spectra for Detection of Misfired Engine Cylinder
Authors: Lee Chong-Won , Han Yun-Sik , Park Jong-Po
Published: March 2021

A powerful diagnostic method of cylinder power faults, which uses the two-sided directional power spectra of complex-valued engine vibration signals, is presented and tested with an automobile engine. As the spectral estimators, the AR, ML and FFT methods are compared and the multi-layer neural network is employed for pattern recognition. Experimental results show that the success rate for identifying the misfired cylinder is higher with the combined AR and ML estimator than the FFT method.
Reduction of the Junction Degrees of Freedom Before Assembly in Dynamic Substructuring
Authors: Brahmi Khaled , Bouhaddi Noureddine , Fillod René
Published: March 2021

The dynamic behavior of large complex structures is often achieved by substructuring methods where the substructures are modeled separately. One of advantages of these methods is that one component may be changed without remodeling the others. This is particularly useful when components are designed and analyzed by different organizations.

Althougth these methods use a variety of reduction techniques to couple the substructure models, the size of the final condensed system remains important due to large number of the junction degrees of freedom (Abv: dof) required for assembly.

In this paper, we propose a method using a modal projection on the Ritz basis which, when correctly chosen, reduces the number of these dof before the assembly of substructures. This method is applied to certain substructuring methods: dynamic condensation, modal synthesis using free or constrained interfaces.
Multiresolution Reproducing Kernel Particle Methods in Acoustic Problems
Authors: Liu W. K. , Chang C. T. , Chen Y. , Uras R. A.
Published: March 2021

In the analysis of complex phenomena of acoustic systems, the computational modeling requires special attention for a realistic representation of the physics. As a powerful tool, the finite element method has been widely used in the study of complex systems. In order to capture the important physical phenomena, p-finite elements and/or hp-finite elements are employed. The reproducing kernel particle methods (RKPM) are emerging as an effective alternative due to the elimination of a mesh, and the ability to analyze a specific frequency range. Additionally, a wavelet particle method based on the multiresolution analysis encountered in signal processing has been developed. The interpolation functions consist of spline functions with built-in window. A variation in the size of the window implies a geometrical refinement, and allows the filtering of the desired frequency range. Preliminary analysis of the wave equation shows the effectiveness of this approach. The frequency/wave number relationship of the continuum case can be closely simulated by using the reproducing kernel particle methods. A similar methodology is also developed for the Timoshenko beam.