bluuebunny/crossref_metadata_2025 huggingface dataset:
Academies in Health Professions Education: A Scoping Review
Authors: Uijtdehaage Sebastian , Ho Ming-Jung , Harvey Emily , Dorris C. Scott , Huggett Kathryn N.
Published: May 2021

Purpose

Thirty years ago, academies were conceived as a sociocultural approach to revitalize the teaching mission of medical schools and to promote educators’ career advancement. The academy movement has grown rapidly and now reaches a broad range of health professions education organizations. The authors conducted a scoping review to map the literature and describe the evidence that guides the formation of new academies and justifies the continuation of existing ones.

Method

The authors searched MEDLINE (via Ovid), Embase (via Elsevier and Ovid), CINAHL (via EBSCOhost), and Web of Science (via Clarivate Analytics) from inception through March 6, 2020, for publications regarding academy-like organizations. They mapped the relevant literature using logic modeling as an organizing framework and included the mission, resources, activities, output, outcomes, and impact of the included academies.

Results

Of the 513 publications identified, 43 met the inclusion criteria, the oldest of which was published in 2000. Most publications were either case reports or perspective/opinion pieces (26, 57.8%), while studies presenting empirical findings were less common (11, 24.4%). Publications showed that academies were diversifying and increasingly were part of a broad range of organizations, including departments, hospitals, health science campuses, and national organizations. The mission, resources, and activities were similar across academies. Evaluation studies were largely limited to process measures, and rigorous studies examining outcomes (i.e., changes in academy participants) and impact on the organization at large were rare.

Conclusions

The increase in the number of academy-related publications parallels the accelerating speed of the academy movement. To sustain this movement, rigorous studies must provide evidence that academies contribute to the revitalization of organizations’ teaching mission and bring about an academic culture where educators thrive and where education is a legitimate career path.
Negative Pressure Neurogenesis: A Novel Approach to Accelerate Nerve Regeneration after Complete Peripheral Nerve Transection
Authors: Mettyas Tamer , Barton Matthew , Sahar Muhammad Sana Ullah , Lawrence Felicity , Sanchez-Herrero Alvaro , Shah Megha , St John James , Bindra Randy
Published: May 2021

Background:

Various modalities to facilitate nerve regeneration have been described in the literature with limited success. We hypothesized that negative pressure applied to a sectioned peripheral nerve would enhance nerve regeneration by promoting angiogenesis and axonal lengthening.

Methods:

Wistar rats’ sciatic nerves were cut (creating ~7 mm nerve gap) and placed into a silicone T-tube, to which negative pressure was applied. The rats were divided into 4 groups: control (no pressure), group A (low pressure: 10 mm Hg), group B (medium pressure: 20/30 mm Hg) and group C (high pressure: 50/70 mm Hg). The nerve segments were retrieved after 7 days for gross and histological analysis.

Results:

In total, 22 rats completed the study. The control group showed insignificant nerve growth, whereas the 3 negative pressure groups showed nerve growth and nerve gap reduction. The true nerve growth was highest in group A (median: 3.54 mm) compared to group B, C, and control (medians: 1.19 mm, 1.3 mm, and 0.35 mm); however, only group A was found to be significantly different to the control group (**P < 0.01). Similarly, angiogenesis was observed to be significantly greater in group A (**P < 0.01) in comparison to the control.

Conclusions:

Negative pressure stimulated nerve lengthening and angiogenesis within an in vivo rat model. Low negative pressure (10 mm Hg) provided superior results over the higher negative pressure groups and the control, favoring axonal growth. Further studies are required with greater number of rats and longer recovery time to assess the functional outcome.
Anti-inflammatory and anti-Helicobacter effects of the Aralia elata hot-water extract
Authors: Lee Se-Won , Lee Jeong Ho
Published: May 2021

Aralia elata contains several bioactive compounds, such as saponin, oleanolic acid, and beta-carotene, which are known widely to control blood pressure and diabetes. In this study, we investigated the anti-Helicobacter pylori, antioxidant, anti-inflammatory, and cytotoxic effects of the extract of A. elata which was procured from Sunchang-gun, South Korea. The extract was prepared using water bath at 80℃ for 5 h. The total polyphenolics content in A. elata hot-water extract was 186.8±2.7 mgGAE/g, and the total flavonoid content was 81.9±1.5 mgQE/g. In addition, the extract exhibited anti-Helicobacter pylori activity and the growth of the bacteria was decreased with increasing concentration of the extract. SC50 value of DPPH radical scavenging activity was 3,274.7±47.7 μg/mL, and ABTS radical scavenging activity was 2,660.1±50.3 μg/mL. Furthermore, A. elata hot-water extract reduced the production of nitric oxide (NO), TNF-α, IL-1β, and IL-6 in LPS-stimulated RAW264.7 cells. Cell viability assay revealed no cytotoxicity in RAW264.7 cells even at a concentration of 100 μg/mL. The results confirmed that A. elata hot-water extract could be used as an antioxidant, antibacterial, and anti-inflammatory agent.
Inhibition of nitric oxide and lipid accumulation by
Sargassum sp. seaweeds and their antioxidant
properties
Authors: You SoHyeon , Jang Miran , Kim Gun-Hee
Published: May 2021

Recently, the use of seaweed has attracted significant attention and has resulted
in several seaweed-based studies for developing health-promoting foods.
Sargassum sp. has been consumed as a part of the diet for
centuries, especially in Asian countries, and has been reported to exhibit
diverse biological effects, such as antioxidant, anti-obesity, and
anti-inflammation effects. The present study involved the evaluation of the
total phenolics content and in vitro antioxidant activities of
seaweed using 2,2’-diphenyl-1-picrylhydrazyl (DPPH) and
2,2’-azinobis-(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) assays.
Moreover, the inhibitory effect of lipid accumulation during the production of
3T3-L1 adipocytes and nitric oxide (NO) in RAW264.7 macrophages were
investigated. The results revealed that Sargassum siliquastrum
contained the highest total phenolics content (36.67 mg GAE/g of extract) and
exhibited the highest antioxidant activity among the 19
Sargassum sp. seaweeds. In terms of the anti-adipogenic
activity, the Sargassum nipponium and Sargassum
siliquastrum extracts significantly inhibited lipid accumulation
(up to 63%) compared to that of the control in 3T3-L1 cells. Additionally, the
Sargassum sagamianum extract inhibited NO production (up to
85%) in lipopolysaccharide-induced RAW264.7 cells. Our results provide evidence
that Sargassum sp. could be useful for the development of
healthy functional foods.
Comparison of the chemical and amino acid compositions of breast
meat of broiler and laying hens
Authors: Jo SeungWha , Yim EunJung , Kim Young-Soo , Lo ChangSik , Shin DongHwa
Published: May 2021

This study aimed to compare the chemical and amino acid compositions of the
breast meat of broiler and laying hens, which have low acceptance in the market.
The breast meats were analyzed for the chemical and amino acid compositions of
hydrolysates digested by protease at optimum reaction conditions using the amino
acid analyzer. No significant differences in moisture and ash contents were
detected between the two types of breast meat. However, there were significant
differences in the crude lipid and protein contents of laying hen (1.01% and
23.68%, respectively) and broiler hen (1.54% and 25.41%, respectively) meat
samples. The amino acid contents of the breast meat samples of the laying and
broiler hens were as follows: aspartic acid (6.88% and 9.84%, respectively),
leucine (2.01% and 2.99%, respectively), and arginine (0.97% and 1.32%,
respectively). Furthermore, the broiler meat had higher contents of essential
amino acids such as valine, methionine, isoleucine, leucine, and phenylalanine.
The total essential amino acid contents of the two types of meat were 5.87%
(laying) and 8.29% (broiler), while the branched chain amino acid contents were
2.97% (laying) and 4.60% (broiler). The result of this study suggests that the
hydrolysate of broiler breast meat could possibly be utilized as functional
ingredient for patient foods, elderly food, sports drink and condiment
sources.
Significant and sustained decrease in non-SARS-CoV-2 respiratory viral infections during COVID-19 public health interventions
Authors: Whitman Jeffrey D. , Pham Phong , Bern Caryn , Dekker Elaine M. , Haller Barbara L. , Jain Vivek , Winston Lisa G.
Published: May 2021

Public health interventions to decrease the spread of SARS-CoV-2 were largely implemented in the United States during spring 2020. This study evaluates the additional effects of these interventions on non-SARS-CoV-2 respiratory viral infections from a single healthcare system in the San Francisco Bay Area. The results of a respiratory pathogen multiplex polymerase chain reaction panel intended for inpatient admissions were analyzed by month between 2019 and 2020. We found major decreases in the proportion and diversity of non-SARS-CoV-2 respiratory viral illnesses in all months following masking and shelter-in-place ordinances. These findings suggest real-world effectiveness of nonpharmaceutical interventions on droplet-transmitted respiratory infections.
Lipid Droplets and Ferritin Heavy Chain: a Devilish Liaison in Cancer Radioresistance
Authors: Tirinato L. , Marafioti M.G. , Pagliari F. , Jansen J. , Aversa I. , Hanley R. , Nisticò C. , Garcia-Calderón D. , Genard G. , Guerreiro J. F. , Costanzo F.S. , Seco J.
Published: May 2021

Although much progress has been made in cancer treatment, the molecular mechanisms underlying cancer radioresistance (RR) as well as the biological characteristic of radioresistant cancer cells still need to be clarified. In this regard, we discovered that breast, bladder, lung, neuroglioma and prostate 6 Gy X-ray resistant cells were characterized by an increase of Lipid Droplet (LD) number and that the cells containing highest LDs showed the highest clonogenic potential after irradiation. Moreover, we observed that LD content was tightly connected with the iron metabolism and in particular with the presence of the ferritin heavy chain (FTH1). In fact, breast and lung cancer cells silenced for the FTH1 gene showed a reduction in the LD numbers and, by consequence, became radiosensitive. FTH1 restoration as well as iron-chelating treatment by Deferoxamine were able to restore the LD amount and RR. Overall, these results provide evidence of a novel molecular mechanism behind RR in which LDs and FTH1 are tightly connected to each other, a synergistic effect which might be worth deeply investigating in order to make cancer cells more radiosensitive and improve the efficacy of radiation treatments.
Cortico-spinal coupling along descending pain system differentiates between opioid and saline treatment in healthy participants
Authors: Tinnermann Alexandra , Sprenger Christian , Büchel Christian
Published: May 2021

Opioids are potent analgesic drugs with widespread cortical, subcortical and spinal targets. In particular, the central pain system comprising ascending and descending pain pathways has high opioid receptor densities and is thus crucial for opioid analgesia. Here, we investigated effects of the opioid remifentanil in a large sample (n=78) of healthy male participants using combined cortico-spinal fMRI. This approach offers the possibility to measure BOLD responses simultaneously in the brain and spinal cord allowing us to investigate the role of cortico-spinal coupling in opioid analgesia. Our data show that opioids altered activity in regions involved in pain processing such as somatosensory regions including the spinal cord and pain modulation such as prefrontal regions. Moreover, coupling strength along the descending pain system, i.e. between the medial prefrontal cortex, periaqueductal gray and spinal cord was stronger in participants who reported stronger analgesia during opioid treatment while the reversed pattern was observed in the control group. These results indicate that coupling along the descending pain pathway is a potential mechanism of opioid analgesia and can differentiate between opioid analgesia and unspecific reductions in pain such as habituation.
On the Contribution of Reproductive and Offspring Investment on Fertility: Human and Animal Societies
Authors: Bukkuri Anuraag
Published: May 2021

Differences in investment into reproduction or offspring rearing are plentiful throughout the world, from the cells inside our bodies to complex sociological interactions among humans. Such differences can lead to profound impacts on species’ fitness, fertility, and reproductive rates, sometimes in startling ways. In this paper, we create a simple game-theoretical model to qualitatively investigate the effects of such differential investment. We focus on fertility in human societies and show that more wealthy individuals produce more offspring within a a mating group. However, when assortative mating mechanisms are introduced, this effectively leads to a speciation event, and a higher reproduction rate for poorer individuals is noticed, capturing what we call the “wealthy-to-poor switch”. We discuss extensions and implications of this work to nupital gifts in ecology and to clonal competition in cancer cell lines under the influence of treatment.
The protective effect of aspirin in colorectal carcinogenesis: a multiscale computational study from mutant evolution to age incidence curves
Authors: Wang Yifan , Boland C. Richard , Goel Ajay , Wodarz Dominik , Komarova Natalia L.
Published: May 2021

Aspirin intake has been shown to lead to significant protection against colorectal cancer, e.g. with an up to two-fold reduction in colorectal adenoma incidence rates at higher doses. The mechanisms contributing to protection are not yet fully understood. While aspirin is an anti-inflammatory drug and can thus influence the tumor microenvironment, in vitro and in vivo experiments have recently shown that aspirin can also have a direct effect on cellular kinetics and fitness. It reduces the rate of tumor cell division and increases the rate of cell death. The question arises whether such changes in cellular fitness are sufficient to significantly contribute to the epidemiologically observed protection. To investigate this, we constructed a class of mathematical models of in vivo evolution of advanced adenomas, parameterized it with available estimates, and calculated population level incidence. Fitting the predictions to age incidence data revealed that only a model that included colonic crypt competition can account for the observed age-incidence curve. This model was then used to predict modified incidence patterns if cellular kinetics were altered as a result of aspirin treatment. We found that changes in cellular fitness that were within the experimentally observed ranges could reduce advanced adenoma incidence by a sufficient amount to account for age incidence data in aspirin-treated patient cohorts. While the mechanisms that contribute to the protective effect of aspirin are likely complex and multi-factorial, our study demonstrates that direct aspirin-induced changes of tumor cell fitness can significantly contribute to epidemiologically observed reduced incidence patterns.
A fluorescence-based genetic screen reveals diverse mechanisms silencing small RNA signaling inE. coli
Authors: Chen Jiandong , To Leann , de Mets Francois , Luo Xing , Majdalani Nadim , Tai Chin-Hsien , Gottesman Susan
Published: May 2021

As key players of gene regulation in many bacteria, small regulatory RNAs (sRNAs) associated with the RNA chaperone Hfq shape numerous phenotypic traits, including metabolism, stress response and adaptation as well as virulence. sRNAs can alter target mRNA translation and stability via base pairing. sRNA synthesis is generally under tight transcriptional regulation, but other levels of regulation of sRNA signaling are less well understood. Here we used a fluorescence-based functional screen to identify new regulators that can quench sRNA signaling of the iron-responsive sRNA RyhB inE. coli. The identified regulators fell into two classes, general regulators (affecting signaling by many sRNAs) and RyhB-specific regulators; we focused on the specific ones here. General regulators include three Hfq-interacting sRNAs, CyaR, ChiX and McaS, previously found to act through Hfq competition, RNase T, a 3′-5′ exonuclease not previously implicated in sRNA degradation, and YhbS, a putative GCN5-related N-acetyltransferase (GNAT). Two new specific regulators were identified. AspX, a novel 3′end-derived small RNA, specifically represses RyhB signaling via an RNA sponging mechanism. YicC, a previously uncharacterized but widely conserved protein, triggers rapid RyhB degradation via collaboration with the exoribonuclease PNPase. These findings greatly expand our knowledge of regulation of bacterial sRNA signaling and suggest complex regulatory networks for controlling iron homeostasis in bacteria. The fluorescence-based genetic screen system described here is a powerful tool expected to accelerate the discovery of novel regulators of sRNA signaling in many bacteria.

Significance

The ability to promptly switch genes on and off allows bacteria to adapt rapidly to changing environments for better survival. Many sRNAs, including RyhB, a sRNA made in response to iron starvation, are important switches in bacteria. We discovered new factors that can keep the sRNA switch off by using a facile genetic screen platform. These new factors include a new RNA sponge and an adaptor protein for a ribonuclease, providing new perspectives on controlling sRNA signaling in bacteria.
Set4 coordinates the activity of histone deacetylases and regulates stress-responsive gene expression within subtelomeric regions in yeast
Authors: Jethmalani Yogita , Tran Khoa , Jaiswal Deepika , Jezek Meagan , Ramos Mark , Amos Shandon , Garcia Eric Joshua , Negesse Maraki Y. , Sun Winny , Park DoHwan , Green Erin M.
Published: May 2021

The yeast chromatin protein Set4 is a member of the Set3-subfamily of SET domain proteins which play critical roles in the regulation of gene expression in diverse developmental and environmental contexts, although they appear to lack methyltransferase activity. The molecular functions of Set4 are relatively unexplored, likely due to its low abundance in standard growth conditions. We previously reported that Set4 promotes survival during oxidative stress and regulates expression of stress response genes via stress-dependent chromatin localization. In this study, global gene expression analysis and investigation of histone modification status has revealed a role for Set4 in maintaining gene repressive mechanisms within yeast subtelomeres under both normal and stress conditions. We show that Set4 works in a partially overlapping pathway to the SIR complex and the histone deacetylase Rpd3 to maintain proper levels of histone acetylation and expression of stress response genes encoded in subtelomeres. This role for Set4 is particularly critical for cells under hypoxic conditions, and the loss of Set4 decreases cell fitness and cell wall integrity in hypoxia. These findings uncover a new regulator of subtelomeric chromatin that is key to stress defense pathways and demonstrate a function for yeast Set4 in regulating repressive, heterochromatin-like environments.
Inferring the COVID-19 infection fatality rate in the community-dwelling population: a simple Bayesian evidence synthesis of seroprevalence study data and imprecise mortality data
Authors: Campbell Harlan , Gustafson Paul
Published: May 2021

Estimating the COVID-19 infection fatality rate (IFR) has proven to be particularly challenging –and rather controversial– due to the fact that both the data on deaths and the data on the number of individuals infected are subject to many different biases. We consider a Bayesian evidence synthesis approach which, while simple enough for researchers to understand and use, accounts for many important sources of uncertainty inherent in both the seroprevalence and mortality data. With the understanding that the results of one’s evidence synthesis analysis may be largely driven by which studies are included and which are excluded, we conduct two separate parallel analyses based on two lists of eligible studies obtained from two different research teams. The results from both analyses are rather similar. With the first analysis, we estimate the COVID-19 IFR to be 0.31% (95% credible interval of (0.16%, 0.53%)) for a typical community-dwelling population where 9% of the population is aged over 65 years and where the gross-domestic product at purchasing-power parity (GDP at PPP) per capita is $17.8k (the approximate worldwide average). With the second analysis, we obtain 0.32% (95% credible interval of (0.19%, 0.47%)). Our results suggest that, as one might expect, lower IFRs are associated with younger populations (and may also be associated with wealthier populations). For a typical community-dwelling population with the age and wealth of the United States we obtain IFR estimates of 0.43% and 0.41%; and with the age and wealth of the European Union, we obtain IFR estimates of 0.67% and 0.51%.

Above all, what’s needed is humility in the face of an intricately evolving body of evidence. The pandemic could well drift or shift into something that defies our best efforts to model and characterize it.

Siddhartha Mukherjee,The New Yorker

February 22, 2021
Construction and Validation of the Ohio Children’s Opportunity Index
Authors: Fareed Naleef , Singh Priti , Jonnalagadda Pallavi , Swoboda Christine M. , Odden Colin , Doogan Nathan
Published: May 2021

Objective

To describe the development of an area-level measure of children’s opportunity, the Ohio Children’s Opportunity Index (OCOI).

Data Sources/Study Setting

Secondary data were collected from US census based-American Community Survey (ACS), US Environmental Protection Agency, US Housing and Urban Development, Ohio Vital Statistics, US Department of Agriculture-Economic Research Service, Ohio State University Center for Urban and Regional Analysis, Ohio Incident Based Reporting System, IPUMS National Historical Geographic Information System, and Ohio Department of Medicaid.

Study Design

OCOI domains were selected based on existing literature, which included family stability, infant health, children’s health, access, education, housing, environment and criminal justice domains. The composite index was developed using an equal weighting approach. Validation analyses were conducted between OCOI and health and race-related outcomes.

Data Collection/Extraction Methods

Data were aggregated at the census tract level.

Principal Findings

Composite OCOI scores ranged from 0-100 with an average value of 74.82 (SD, 17.00), was negatively skewed. Census tracts in the major metropolitan cities across Ohio represented 76% of the total census tracts in the least advantaged OCOI septile. OCOI served as a significant predictor of health and race-related outcomes. The average life expectancy at birth of children born in the most advantaged septile was approximately nine years more than those born in the least advantaged septile. Increases in OCOI were associated with decreases in proportion of Black (48 points lower in the most advantaged vs least advantaged septile), p<0.001) and Minority populations (54 points lower in most advantaged vs least advantaged septile, p<0.001).

Conclusion

As the first opportunity index developed for children in Ohio, the OCOI is a valuable resource for policy reform, especially related to health equity. Health care providers can use it to obtain more holistic views on their patients and implement interventions that can tackle barriers to childhood development.
The cerebellum as a moderator of negative bias of facial expression processing in depressive patients
Authors: Nakamura Anna , Yomogida Yukihito , Ota Miho , Matsuo Junko , Ishida Ikki , Hidese Shinsuke , Kunugi Hiroshi
Published: May 2021

Background

Negative bias—a mood-congruent bias in emotion processing—is an important aspect of major depressive disorder (MDD), and such a bias in facial expression recognition has a significant effect on patients’ social lives. Neuroscience research shows abnormal activity in emotion-processing systems regarding facial expressions in MDD. However, the neural basis of negative bias in facial expression processing has not been explored directly.

Methods

Sixteen patients with MDD and twenty-three healthy controls (HC) who underwent an fMRI scan during an explicit facial emotion task with happy to sad faces were selected. We identified brain areas in which the MDD and HC groups showed different correlations between the behavioral negative bias scores and functional activities.

Results

Behavioral data confirmed the existence of a higher negative bias in the MDD group. Regarding the relationship with neural activity, higher activity of happy faces in the posterior cerebellum was related to a higher negative bias in the MDD group, but lower negative bias in the HC group.

Limitations

The sample size was small, and the possible effects of medication were not controlled for in this study.

Conclusions

We confirmed a negative bias in the recognition of facial expressions in patients with MDD. fMRI data suggest the cerebellum as a moderator of facial emotion processing, which biases the recognition of facial expressions toward their own mood.
KAHRP dynamically relocalizes to remodeled actin junctions and associates with knob spirals in P. falciparum-infected erythrocytes
Authors: Sanchez Cecilia P. , Patra Pintu , Chang Shih-Ying , Karathanasis Christos , Hanebutte Lukas , Kilian Nicole , Cyrklaff Marek , Heilemann Mike , Schwarz Ulrich S. , Kudryashev Mikhail , Lanzer Michael
Published: May 2021

The knob-associated histidine-rich protein (KAHRP) plays a pivotal role in the pathophysiology of Plasmodium falciparum malaria by forming membrane protrusions in infected erythrocytes, which anchor parasite-encoded adhesins to the membrane skeleton. The resulting sequestration of parasitized erythrocytes in the microvasculature leads to severe disease. Despite KAHRP being an important virulence factor, its physical location within the membrane skeleton is still debated, as is its function in knob formation. Here, we show by super-resolution microscopy that KAHRP initially associates with various skeletal components, including ankyrin bridges, but eventually co-localizes with remnant actin junctions. We further present a 35Å map of the spiral scaffold underlying knobs and show that a KAHRP-targeting nanoprobe binds close to the spiral scaffold. Single-molecule localization microscopy detected ∼60 KAHRP molecules per knob. We propose a dynamic model of KAHRP organization and a function of KAHRP in attaching other factors to the spiral scaffold.
The repeat region of the circumsporozoite protein is an elastic linear spring with a functional role in Plasmodium sporozoite motility
Authors: Balaban Amanda E. , Kanatani Sachie , Mitra Jaba , Gregory Jason , Vartak Natasha , Sinnis-Bourozikas Ariadne , Frischknecht Fredrich , Ha Taekjip , Sinnis Photini
Published: May 2021

The circumsporozoite protein (CSP) forms a dense coat on the surface of the sporozoite, the infective stage of the malaria parasite. The central repeat region of CSP is a critical component of the only licensed malaria vaccine yet little is known about its structure or function. We found that sporozoite mutants with severely truncated or scrambled repeats have impaired motility due to altered adhesion site formation and dynamics, suggesting that the CSP repeats provide a cohesive environment in which adhesion sites can form. We hypothesized that biophysical properties of the repeats are important in this role and interrogated this using single-molecule fluorescence-force spectroscopy. We show that the repeats are a stiff, linear spring with elastic properties, dependent upon length and lost when the repeats are scrambled. These data are the first evidence that the CSP repeat region serves a functional role during infection and motility, likely mediated through its biophysical properties.

No clear function of the central repeat region of the malaria circumsporozoite protein has been described to date, despite its central role in the only licensed malaria vaccine. Here we use mutational analysis and single-molecule fluorescence-force spectroscopy to describe the structural properties and determine the function of this conserved region and important vaccine target.

Highlights

The CSP repeats have properties of a linear spring

Scrambling or large truncations of the repeats leads to defects in sporozoite motility

Motility defects are attributed to abnormal formation of adhesion sites
Polymerization of C9 enhances bacterial cell envelope damage and killing by membrane attack complex pores
Authors: Doorduijn Dennis J. , Heesterbeek Dani A.C. , Ruyken Maartje , de Haas Carla J.C. , Stapels Daphne A.C. , Aerts Piet C. , Rooijakkers Suzan H. M. , Bardoel Bart W.
Published: May 2021

Complement proteins can form Membrane Attack Complex (MAC) pores that directly kill Gram-negative bacteria. MAC pores assemble by stepwise binding of C5b, C6, C7, C8 and finally C9, which can polymerize into a transmembrane ring of up to 18 C9 monomers. It is still unclear if the assembly of a polymeric-C9 ring is necessary to sufficiently damage the bacterial cell envelope to kill bacteria, because a robust way to specifically prevent polymerization of C9 has been lacking. In this paper, polymerization of C9 was prevented without affecting the binding of C9 to C5b-8 by locking the first transmembrane helix domain of C9. We show that polymerization of C9 strongly enhanced bacterial cell envelope damage and killing by MAC pores for severalEscherichia coliandKlebsiellastrains. Moreover, we show that polymerization of C9 is impaired on complement-resistantE. colistrains that survive killing by MAC pores. Altogether, these insights are important to understand how MAC pores kill bacteria and how bacterial pathogens can resist MAC-dependent killing.
Spatiotemporal 3D image registration for mesoscale studies of brain development
Authors: Shuvaev Sergey , Lazutkin Alexander , Kiryanov Roman , Anokhin Konstantin , Enikolopov Grigori , Koulakov Alexei A.
Published: May 2021

Comparison of brain samples representing different developmental stages often necessitates registering the samples to common coordinates. Although the available software tools are successful in registering 3D images of adult brains, registration of perinatal brains remains challenging due to rapid growth-dependent morphological changes and variations in developmental pace between animals. To address these challenges, we propose a multi-step algorithm for the registration of perinatal brains. First, we optimized image preprocessing to increase the algorithm’s sensitivity to mismatches in registered images. Second, we developed an attention-gated simulated annealing (Monte Carlo) procedure capable of focusing on the differences between perinatal brains. Third, we applied classical multidimensional scaling (CMDS) to align (“synchronize”) brain samples in time, accounting for individual development paces. We tested this multi-step algorithm on 28 samples of whole-mounted perinatal mouse brains (P0 – P9) and observed accurate registration results. Our computational pipeline offers a runtime of several minutes per brain on a personal computer and automates brain registration tasks including mapping brain data to atlases, comparison of averaged experimental groups, and monitoring brain development dynamics.
Uncoupling of Chromatin Assembly from DNA Replication in Sciara Reveals a Domain of Postreplicative Immature Chromatin
Authors: Urnov Fyodor D. , Scheer Ulrich , Zentgraf Hanswalter , Smith Heidi S. , Gerbi Susan A.
Published: May 2021

DNA replication in dividing eukaryotic cells imposes a requirement for the faithful recreation on the newly synthesized chromatids of the nucleoprotein architecture of parent chromosomes. Practically nothing is known about the structure of postreplicative immature chromatin—a very short-lived entity (< 30 min.). We report here the unexpected discovery that during DNA amplification of locus II/9A in salivary gland polytene chromosomes of the fungus fly Sciara coprophila, DNA replication fork passage is uncoupled from postreplicative chromatin assembly; this enables visualization and analysis of chromatin fibers disassembled by DNA replication. We used electron microscopy to visualize a wealth of low nucleosome density immature chromatin fibers in preparations of Sciara chromatin from amplification-stage tissue. Remarkably, as gauged by high sensitivity to micrococcal nuclease and an unusually short length of DNA associated with each histone octamer, we found that locus II/9A which undergoes amplification and is replicated once every 4-6 hrs.—but not the bulk genome or a replicatively quiescent DNA stretch—was maintained in such an ummature fiber for ca. 24 hrs. Following amplification, locus II/9A assumed conventional chromatin organization, indicating that the epigenetic mark targeting nascent DNA to the chromatin assembly machinery is stable for several hours. We propose that this very unusual prolonged maintenance of a segment of the genome in immature chromatin facilitates access by the basal transcriptional machinery to the amplified DNA, and thus is an evolutionary adaptation to the demand for high transcription from genes that reside in the amplified loci.
Students' perception of learning from entrepreneurship education programs and entrepreneurial intention in Latin America
Authors: Lopez Tatiana , Alvarez Claudia , Martins Izaias , Perez Juan P. , Románn-Calderón Juan Pablo
Published: May 2021

Purpose

Drawing on entrepreneurship education and entrepreneurial intention literature, this paper develops and tests a model that aims to explain the relationship between students' perception of learning from entrepreneurship education programs (EEP), the theory of planned behavior and entrepreneurial intention across Latin American countries.

Design/methodology/approach

This study uses data from the Global University Entrepreneurship Spirit Student’s Survey (GUESSS) project 2018 for 11 Latin American countries. Structural equation modeling is used to validate the theoretical model; this offers advantages over traditional multivariate techniques in evaluating measurement errors, estimation of latent variables and specification of models.

Findings

The main results suggest that a positive perception of learning from EEP is related to the antecedents of entrepreneurial intention. Moreover, attitude toward entrepreneurial behavior and perceived behavior control positively influences entrepreneurial intention across Latin American undergraduate students. The findings contribute to a better understanding of the role of EEP in terms of the antecedents of the intention and, in addition, provide evidence to the theory of planned behavior from a large sample in an emerging region.

Originality/value

The theory of planned behavior is one of the most important theoretical frameworks to explain entrepreneurial intention. However, in Latin American countries, quality research is hindered by the lack of data and valid measures. Therefore, the paper adds value by looking at the perception of learning from EEP and its relationship with the antecedents of intention. Likewise, it validates the dimensions of the theory of planned behavior and its relationship to entrepreneurial intention, considering a broad sample of university students in Latin America.
Data cleaning issues in class imbalanced datasets: instance selection and missing values imputation for one-class classifiers
Authors: Wang Zhenyuan , Tsai Chih-Fong , Lin Wei-Chao
Published: May 2021

Purpose

Class imbalance learning, which exists in many domain problem datasets, is an important research topic in data mining and machine learning. One-class classification techniques, which aim to identify anomalies as the minority class from the normal data as the majority class, are one representative solution for class imbalanced datasets. Since one-class classifiers are trained using only normal data to create a decision boundary for later anomaly detection, the quality of the training set, i.e. the majority class, is one key factor that affects the performance of one-class classifiers.

Design/methodology/approach

In this paper, we focus on two data cleaning or preprocessing methods to address class imbalanced datasets. The first method examines whether performing instance selection to remove some noisy data from the majority class can improve the performance of one-class classifiers. The second method combines instance selection and missing value imputation, where the latter is used to handle incomplete datasets that contain missing values.

Findings

The experimental results are based on 44 class imbalanced datasets; three instance selection algorithms, including IB3, DROP3 and the GA, the CART decision tree for missing value imputation, and three one-class classifiers, which include OCSVM, IFOREST and LOF, show that if the instance selection algorithm is carefully chosen, performing this step could improve the quality of the training data, which makes one-class classifiers outperform the baselines without instance selection. Moreover, when class imbalanced datasets contain some missing values, combining missing value imputation and instance selection, regardless of which step is first performed, can maintain similar data quality as datasets without missing values.

Originality/value

The novelty of this paper is to investigate the effect of performing instance selection on the performance of one-class classifiers, which has never been done before. Moreover, this study is the first attempt to consider the scenario of missing values that exist in the training set for training one-class classifiers. In this case, performing missing value imputation and instance selection with different orders are compared.
Unsteady conjugate heat transfer with combined effects of MHD and moving conductive elliptic object in CNT-water nanofluid with ventilation ports
Authors: Selimefendigil Fatih , Öztop Hakan F.
Published: May 2021

Purpose

The purpose of this paper is to analyze the unsteady conjugate mixed convective heat transfer characteristics in a vented porous cavity under the combined effects of moving conductive elliptic object and magnetic field.

Design/methodology/approach

The finite element method and arbitrary Lagrangian-Eulerian (ALE), impacts of Reynolds number, Hartmann number, aspect ratio of the conductive ellipse and moving speed of the object on the hydro-thermal performance are analyzed.

Findings

It was observed that the dynamic characteristics of the local and average Nu number of each hot wall are different. Magnetic field strength increment resulted in the enhancement of average Nu number for bot steady and transient case while the optimum case for best hydro-thermal performance is achieved for highest Ha number and non-dimensional time of 10. Higher value of average Nu and lower pressure coefficient are achieved for aspect ratio of 4 and non-dimensional time of 10. When the moving velocity of the conductive ellipse is considered, 42% enhancement in the average Nu is obtained at non-dimensional time of 20 and object velocity equals to 0.012 times entering fluid velocity in the negative y direction while the pressure coefficient is higher. The moving object is used as a useful tool to control the dynamic features of heat transfer in a vented cavity.

Originality/value

The present method of convective heat transfer control inside a vented cavity with a moving elliptic object is novel and can be used as an effective tool with magnetic field effects owing to diverse use of convection in cavities with vented ports in many practical thermal engineering systems.
Determinants of multi-destination travel in Vietnam: a rational choice perspective
Authors: Do Hao Thi Kim , Hoang Dung Phuong , Pham Thuy Thu
Published: May 2021

Purpose

This paper aims to examine the factors affecting travelers’ decision to select more than one destination in their trips. Drawn from the rational choice theory, this study posits that the selection of multi-destination tours, as a rational choice, is determined by the travelers’ perception of costs and benefits associated with that choice.

Design/methodology/approach

The conceptual model was developed from both an exploratory research with in-depth interview and the literature. A logistic regression model linking four explanatory variables representing perceived benefits and costs of multi-destination option with travelers’ choice of multi-destination trips. The conceptual model is controlled for diversity of travel purposes; tour group size; type of travel arrangement and travelers’ demographic characteristics while the research context of multi-destination travel within Phu Yen – Dak Lak – Gia Lai – Binh Dinh helps control for the characteristics of the destination set (spatial proximity and traffic convenience). The conceptual model was tested based on data collected from 1,361 Vietnamese travelers who have ever visited at least one of the four provinces.

Findings

This study finds that perceived benefits in terms of diversifying tourism experiences and perceived costs of traveling in multiple places compared to taking single trips represent the most significant drivers for tourists’ selection of multi-destination tours. In addition, the diversity of travel purposes and tour group size have a positive and significant impact on the demand for traveling more than one destination in a trip. Moreover, the richer, older and married travelers have a significantly higher tendency to select multi-destination packages.

Practical implications

The research findings provide important strategic implications for promoting multi-destination trips, thereby, maximizing economic benefits from tourism.

Originality/value

While multi-destination travel patterns have been examined empirically in individual studies sporadically without a common theoretical background, this research makes some progress on this front by using the rational choice theory to connect the relative contributions of those factors to the travelers’ choice of multi-destination trips. Specifically, this study provides a new perspective in explaining the selection of multi-destination trips – from tourists’ perceptions about costs and benefits associated with that choice.
Empirical identification of skills gaps between chief information officer supply and demand: a resource-based view using machine learning
Authors: Barnes Stuart , Rutter Richard N. , La Paz Ariel I. , Scornavacca Eusebio
Published: May 2021

Purpose

The role of emerging digital technologies is of growing strategic importance as it provides significant competitive advantage to organisations. The chief information officer (CIO) plays a pivotal role in facilitating the process of digital transformation. Whilst demand continues to increase, the supply of suitably qualified applicants is lacking, with many companies forced to choose information technology (IT) or marketing specialists instead. This research seeks to analyse the organisational capabilities required and the level of fit within the industry between CIO requirements and appointments via the resource-based view.

Design/methodology/approach

Job postings and CIO curriculum vitae were collected and analysed through the lens of organisational capability theory using the machine learning method of Latent Dirichlet Allocation (LDA).

Findings

This research identifies gaps between the capabilities demanded by organisations and supplied by CIOs. In particular, soft, general, non-specific capabilities are over-supplied, while rarer specific skills, qualifications and experience are under-supplied.

Practical implications

The research is useful for practitioners (e.g. potential CIO candidates) to understand current market requirements and for companies aiming to develop internal training that meet present and future skill gaps. It also could be useful for professional organisations (e.g. CIO Forum) to validate the need to develop mentoring schemes that help meet such high demand and relative undersupply of qualified CIOs.

Originality/value

By applying LDA, the paper provides a new research method and process for identifying competence requirements and gaps as well as ascertaining job fit. This approach may be helpful to other domains of research in the process of identifying specific competences required by organisations for particular roles as well as to understand the level of fit between such requirements and a potential pool of applicants. Further, the study provides unique insight into the current supply and demand for the role of CIO through the lens of resource-based view (RBV). This provides a contribution to the stream of information systems (IS) research focused on understanding CIO archetypes and how individual capabilities provide value to companies.
Public sector fraud: the Malaysian perspective
Authors: Zahari Afzal Izzaz , Said Jamaliah , Muhamad Nurisyal
Published: May 2021

Purpose

This paper aims to explore and compare the perception of public sector employees on fraud and associated fraud behaviours.

Design/methodology/approach

The population of this study comprised 44 managers from the Malaysian Federal government departments. The analysis was based on an open-response questionnaire using data-driven thematic analysis. This was based on the context and latent content of the respondents. The items in the questionnaire examined the perceived definition, actions and experience of corruption in their departments.

Findings

The findings revealed that respondents acknowledged that bribery as one of the central element of fraud. They recognise fraudulent behaviour and practice in their organisation together with sharing these experiences in the study. Common results indicate that leaders play a major role in shaping the organisation as they present themselves as a model to the mployees. From the human resource perspective, having multiple side businesses while being in employed in the government sector would heavily impact performance and accountability.

Research limitations/implications

Fraud is observed as a practice that needs to be addressed to improve government efficiency. The uniqueness was that the respondents acknowledged the existence of fraud and its implications through the activities of bribery, abuse of power and giving out favours. There is a need for organisations to focus on transparency and value to mitigate fraud.

Practical implications

This paper contributes towards the continuous effort in expanding fraud literature and human behaviour. The data obtained was distinctive in terms of the perspective of a developing economy and such fraud information and responses are different as compared to developed economies.

Originality/value

The empirical study of the public sector organisations enables important contribution towards effective public governance and administration. The results have important implications for preparing functional strategic management and controls for the public sector.