bluuebunny/crossref_metadata_2025 huggingface dataset:
Towards a Korean Sustainable Business Model at National Level: The Influence of Cultural and Political Perceptions of National Image on Consumers’ Behavior
Authors: Yoon Seongwon , Kim Sungsoo
Published: June 2021

Despite the increasing uptake of the term sustainable business model (SBM), the concept has mainly focused on business strategies. However, integrating the SBM into a longer-term and macroscopic framework would make it more sustainable. This article explored the SBM as a national strategy that operates beyond a corporate level. In this respect, the study examined the ways in which cultural and political perceptions of a nation can influence consumers’ choices. This article particularly examined the explanatory power of two ideational driving forces: perceptions of cultural heritage, and perceptions of politics and foreign relations. By assessing a dataset of the views of 223 African students studying in Korea, this study confirmed that national image meaningfully affects consumer behavior (intention to recommend). Furthermore, the study provided new evidence that cultural and political perceptions of a nation have a significantly positive effect on national image. It was also found that national image played a role as a mediating variable relating to cultural/political perceptions and intention to recommend. By extending the concept of the SBM to a national level, this article lays the foundation for a win–win situation between decision makers in both business and political sectors.
The Hindrances to Obtaining Protected Geographical Indications for Products in Mexico. Case Study of Dairy Farming in the Cienega de Chapala, Michoacan
Authors: Reyes-Chávez Peter Paul , Pensado-Leglise Mario del Roble , Cruz-Cárdenas Gustavo , Flores-Magallón Rebeca
Published: June 2021

The aim of this article is to analyze why there are hindrances to the development of PGI products in Mexico, based on the case study of dairy farming in the Cienega de Chapala, Michoacan. Currently, local dairy production satisfies the demand of a parastatal company, marginally supplies the local consumption of fresh milk and is the supplier of the input for the production of a typical low-value ranchero cheese with local demand. In addition, there was a negative impact of NAFTA on local products, and it persists with the recent USMCA. However, with further development of collective action of local dairy farmers, it is possible to promote PGIs for the regional market by taking advantage of the opportunity offered by the new labeling policy of the current federal government. The methodology is a combination of qualitative and quantitative; 68 interviews were conducted with dairy farmers in the study area, and MFA and ATLAS.ti software were used. The results highlight that socio-environmental problems and market failures are related to the obstacles such as the lack of collective action of dairy farmers and the absence of a local governance system that regulates the market and promotes quality, food safety and sustainable practices in the territory.
Dynamic Inventory Routing and Pricing Problem with a Mixed Fleet of Electric and Conventional Urban Freight Vehicles
Authors: Sayarshad Hamid R. , Mahmoodian Vahid , Bojović Nebojša
Published: June 2021

Urban freight transport is essential for supporting our society regarding providing the daily needs of consumers and local businesses. In addition, it allows for the movement of goods, is distributed within urban environments, provides thousands of jobs, and supports economic growth. However, a number of issues are associated with urban freight transport, including environmental impacts, road congestion, and land use of freight facilities that conflicts with residential land use. Electric freight vehicles create zero emissions and provide a sustainable delivery system in comparison with conventional freight vehicles. In this study, a novel dynamic inventory routing and pricing problem under a mixed fleet of electric and conventional vehicles was formulated to minimize the total travel and charging costs. The proposed model is capable of deciding on replenishment times and amounts and vehicle routes. We aimed to determine the maximum social welfare (SW) capable of providing an optimal trade-off between the supplier cost and customer delay that uses a mixed fleet of vehicles. Our computational study was conducted on real data generated from a delivery dataset in Tehran. Under the proposed policy with a fleet of only electric vehicles, the SW increased by 3% while the average customer delay reduced by 15% compared with a fleet of conventional vehicles. The results show that the number of served customers and customer delay would be affected by transitioning conventional urban freight vehicles to electric vehicles. Therefore, the proposed delivery system has a significant impact on energy savings and emissions.
Reviving an Unpopular Tourism Destination through the Placemaking Approach: Case Study of Ngawen Temple, Indonesia
Authors: Priatmoko Setiawan , Kabil Moaaz , Vasa László , Pallás Edit Ilona , Dávid Lóránt Dénes
Published: June 2021

Changes in tourists’ behavior in recent times have been considered a driving force for emphasizing the importance of unpopular tourism destinations as one of the key potentials in the tourism industry in any nation. On the road to reviving unpopular tourism destinations, this study aims to identify the potential tourism aspect and development of the Ngawen Temple in Indonesia. This research applies the placemaking approach as the main strategy for resurrecting Ngawen Temple. By using visitor surveys, visitor flows, and community surveys, this research obtains a clearer assessment for determining the planning development of Ngawen Temple. The research results revealed that unpopular destinations still have the potential to be developed and bring more benefits to the local economy by conducting a comprehensive placemaking approach. Accordingly, possible strategies based on various literature and field observations can provide clues to stakeholders on how to use their tourism assets to improve local communities’ economies. Some of the most frequently proposed strategies are the following: link the unpopular destination with other popular ones through structured tourism trips; design a “tourist trap,” which is a created place to hold tourists longer in a destination using new additional facilities; improve the infrastructure; and establish more creative tourism spaces, such as tourism centers.
Evaluation of Thermal Comfort Performance of a Vertical Garden on a Glazed Façade and Its Effect on Building and Urban Scale, Case Study: An Office Building in Barcelona
Authors: Bagheri Moghaddam Faezeh , Fort Mir Josep Maria , Navarro Delgado Isidro , Redondo Dominguez Ernesto
Published: June 2021

The aim of this paper is to investigate the thermal performance of vertical gardens by comparing the thermal comfort of bare (glazed) and green façades in the Mediterranean climate. The proposal consists of applying a vegetation layer on a glazed façade that could control solar radiation and reduce indoor air temperatures. This study investigates the thermal performance of green façades of an office building in the Mediterranean climate. For this purpose, the Gas Natural Fenosa Office Building as a case study was simulated, that is located on a site next to the coastline in Barcelona. Dynamic building energy simulation was used to determine and assess indoor thermal conditions and, for this reason, the IES VE as a simulation tool has been utilized. Thermal comfort was assessed through the adaptive comfort approach and results were analyzed and presented in the terms of indoor comfort conditions during occupied hours. As a result, the article shows that applying a green façade as a vegetation layer caused a reduction in the internal and external façade surface temperatures, as well as the indoor air temperature of the workplace. Additionally, enhancing indoor comfort in summer is closely associated with reducing the external surface temperature. In winter, it also protects the exterior surface from the low temperature of the outside, and all of this greatly increases thermal comfort performance.
An Improved Revenue Distribution Model for Logistics Service Supply Chain Considering Fairness Preference
Authors: Lu Fuqiang , Wang Liying , Bi Hualing , Du Zichao , Wang Suxin
Published: June 2021

Revenue distribution is an important issue in the operations of a logistics service supply chain (LSSC). The existing works on revenue distribution are mostly based on the assumption of rational economic people that are purely self-interested. However, people also have a fairness preference, which impacts people’s decision-making behavior or even the success operations of the LSSC. For a two-level supply chain consisting of logistics service integrator (LSI) and several functional logistics service providers (FLSP), this paper establishes an improved revenue distribution model considering FLSPs’ inequity aversion. Specifically, the BO model (abbreviation of a model proposed by Bolton and Ockenfels in 2000) is improved to describe the FLSPs’ inequity aversion, which is combined into the conventional revenue distribution model. The proposed model aims to maximize the revenue of logistics service supply chain and obtains the best revenue distribution ratio of each member under equilibrium. In the numerical cases, the impacts of inequity aversion and the number of members with inequity aversion on the revenue distribution are discussed, respectively. The results show that a higher degree of FLSP’s advantageous inequity aversion corresponds to a lower revenue distribution ratio; a higher degree of FLSP’s disadvantageous inequity aversion corresponds to a higher revenue distribution ratio. Increasing the number of FLSP members with inequity aversion results in a higher profit of LSI and lower total utility of FLSPs and the utility of the supply chain. The more FLSP members with inequity aversion there are, the higher the LSI’s profit is, and the lower the total utility of FLSPs and the utility of supply chain are. In addition, the revenue distribution ratio of the FLSP increases with its relative fairness revenue coefficient among FLSPs.
Exploratory Analysis of Pedestrian Road Trauma in Finland
Authors: O’Hern Steve , Utriainen Roni , Tiikkaja Hanne , Pöllänen Markus , Sihvola Niina
Published: June 2021

In Finland, all fatal on-road and off-road motor vehicle crashes are subject to an in-depth investigation coordinated by the Finnish Crash Data Institute (OTI). This study presents an exploratory and two-step cluster analysis of fatal pedestrian crashes between 2010 and 2019 that were subject to in-depth investigations. In total, 281 investigations occurred across Finland between 2010 and 2019. The highest number of cases were recorded in the Uusimaa region, including Helsinki, representing 26.4% of cases. Females (48.0%) were involved in fewer cases than males; however, older females represented the most commonly injured demographic. A unique element to the patterns of injury in this study is the seasonal effects, with the highest proportion of crashes investigated in winter and autumn. Cluster analysis identified four unique clusters. Clusters were characterised by crashes involving older pedestrians crossing in low-speed environments, crashes in higher speed environments away from pedestrian crossings, crashes on private roads or in parking facilities, and crashes involving intoxicated pedestrians. The most common recommendations from the investigation teams to improve safety were signalisation and infrastructure upgrades of pedestrian crossings, improvements to street lighting, advanced driver assistance (ADAS) technologies, and increased emphasis on driver behaviour and training. The findings highlight road safety issues that need to be addressed to reduce pedestrian trauma in Finland, including provision of safer crossing facilities for elderly pedestrians, improvements to parking and shared facilities, and addressing issues of intoxicated pedestrians. Efforts to remedy these key issues will further Finland’s progression towards meeting Vision Zero targets while creating a safer and sustainable urban environment in line with the United Nations sustainable development goals.
Major Obstacles to Public-Private Partnership (PPP)-Financed Infrastructure Development in China
Authors: Bashar Toriqul , Fung Ivan W. H. , Jaillon Lara Celine , Wang Di
Published: June 2021

Public-private partnership (PPP)-led infrastructure development has been crucial in China as it has in many other countries. However, several obstacles in the field tend to challenge its development. Based on survey responses from PPP practitioners and professionals in Hong Kong and mainland China, this study analyzes and ranks the key barriers to PPP projects. Our findings suggest that both groups classify the critical obstacles to PPP consistently, albeit with some divergences in ranking them. Reflecting mainly from the perspective of professionals, the study also proposes some suggestions for mitigating these obstacles, so it could contribute to the effective formulation of PPP and successful implementation of PPP-led infrastructure projects in China as well as elsewhere.
Agroecological Strategies to Safeguard Insect Pollinators in Biodiversity Hotspots: Chile as a Case Study
Authors: Henríquez-Piskulich Patricia A. , Schapheer Constanza , Vereecken Nicolas J. , Villagra Cristian
Published: June 2021

Industrial agriculture (IA) has been recognized among the main drivers of biodiversity loss, climate change, and native pollinator decline. Here we summarize the known negative effects of IA on pollinator biodiversity and illustrate these problems by considering the case of Chile, a “world biodiversity hotspot” (WBH) where food exports account for a considerable share of the economy in this country. Most of Chile’s WBH area is currently being replaced by IA at a fast pace, threatening local biodiversity. We present an agroecological strategy for sustainable food production and pollinator conservation in food-producing WBHs. In this we recognize native pollinators as internal inputs that cannot be replaced by IA technological packages and support the development of agroecological and biodiversity restorative practices to protect biodiversity. We suggest four fundamental pillars for food production change based on: (1) sharing the land, restoring and protecting; (2) ecological intensification; (3) localized knowledge, research, and technological development; and (4) territorial planning and implementation of socio-agroecological policies. This approach does not need modification of native pollination services that sustain the world with food and basic subsistence goods, but a paradigm change where the interdependency of nature and human wellbeing must be recognized for ensuring the world’s food security and sovereignty.
The Effect of Blue-Green Infrastructure on Habitat Connectivity and Biodiversity: A Case Study in the Ōtākaro/Avon River Catchment in Christchurch, New Zealand
Authors: Nguyen Thuy Thi , Meurk Colin , Benavidez Rubianca , Jackson Bethanna , Pahlow Markus
Published: June 2021

The natural capital components in cities (“blue-green infrastructure” BGI) are designed to address long-term sustainability and create multi-benefits for society, culture, business, and ecology. We investigated the added value of BGI through the research question “Can the implementation of blue-green infrastructure lead to an improvement of habitat connectivity and biodiversity in urban environments?” To answer this, the Biological and Environmental Evaluation Tools for Landscape Ecology (BEETLE) within the Land Utilisation and Capability Indicator (LUCI) framework was adopted and applied in Christchurch, New Zealand, for the first time. Three ecologically representative species were selected. The parameterisation was based on ecological theory and expert judgment. By implementation of BGI, the percentages of habitats of interest for kereru and paradise shelduck increased by 3.3% and 2.5%, respectively. This leads to improved habitat connectivity. We suggest several opportunities for regenerating more native patches around the catchment to achieve the recommended minimum 10% target of indigenous cover. However, BGI alone cannot return a full suite of threatened wildlife to the city without predator-fenced breeding sanctuaries and wider pest control across the matrix. The socio-eco-spatial connectivity analysed in this study was formalised in terms of four interacting dimensions.
Design, Validation and Implementation of a Questionnaire to Assess Teenagers’ Digital Competence in the Area of Communication in Digital Environments
Authors: Iglesias-Rodríguez Ana , Hernández-Martín Azucena , Martín-González Yolanda , Herráez-Corredera Patricia
Published: June 2021

This article describes the process of design, validation, and implementation (N = 609) of a questionnaire drawn up ad hoc to assess the digital competence of compulsory education students (ages 11 to 13) in the area of communication. The test measures students’ knowledge, skills, and attitudes in the six competences that make up the area of communication, as established in the Framework for the Development and Knowledge of Digital Competence in Europe (DigComp): interacting through new technologies, sharing of information and content, online citizen participation, collaboration through digital technologies, netiquette, and digital identity management. The purposes of the study are to design and validate an instrument to assess compulsory education students’ digital competences in the area of communication based on their knowledge, skills, and attitudes and to analyse such instrument’s psychometric characteristics with special emphasis on its reliability and validity. The method used consisted of the implementation of various psychometric validation techniques and the analysis of the results based on statistical descriptions. Items show adequate discrimination and difficulty indices. Validity was guaranteed through expert judgement and factorial analysis of the test. The conclusion stresses the pressing need for education centres to provide students with adequate educational-communicative training.
Digital Transformation of Marketing Strategies during a Pandemic: Evidence from an Emerging Economy during COVID-19
Authors: Dash Ganesh , Chakraborty Debarun
Published: June 2021

This study explores the relationship between digital marketing practices, customer satisfaction, customer involvement, and purchase intention. The focus is on the life insurance digital marketing strategies during a pandemic and the resultant lockdown and shutdown. This work sought to analyze the digital transformation of marketing practices and the customers’ resultant purchase intentions. COVID-19 was taken as the prevailing pandemic and its impact on the digital transformation of marketing strategies. Five dimensions of digital marketing strategies with eighteen items and three items each of customer satisfaction and purchase intention were considered for practical purposes. It used structural equation modeling to study 535 responses of life insurance customers. Findings indicate that SEM/SEO, display, and E-CRM practices significantly impacted customer satisfaction and purchase intention. Further, a mediation-cum-moderation approach was undertaken. Customer satisfaction significantly affected purchase intention and played a good mediator between digital marketing practices and purchase intention. Additionally, customer involvement moderated the relationship between content marketing and communication with purchase intention. This research work helps life insurance marketers in general. The digital channel managers expressly understand their key areas of strengths regarding the five dimensions of digital marketing strategies. Accordingly, they frame their plans for decision-making to improve customer satisfaction and resultant purchase intentions. It provides a direction for future adoption of specific marketing strategies during a pandemic and consequent shutdown and lockdowns.
Optimization of Sintering Process of Alumina Ceramics Using Response Surface Methodology
Authors: Landek Darko , Ćurković Lidija , Gabelica Ivana , Kerolli Mustafa Mihone , Žmak Irena
Published: June 2021

In this work, alumina (Al2O3) ceramics were prepared using an environmentally friendly slip casting method. To this end, highly concentrated (70 wt.%) aqueous suspensions of alumina (Al2O3) were prepared with different amounts of the ammonium salt of a polycarboxylic acid, Dolapix CE 64, as an electrosteric dispersant. The stability of highly concentrated Al2O3 aqueous suspensions was monitored by viscosity measurements. Green bodies (ceramics before sintering) were obtained by pouring the stable Al2O3 aqueous suspensions into dry porous plaster molds. The obtained Al2O3 ceramic green bodies were sintered in the electric furnace. Analysis of the effect of three sintering parameters (sintering temperature, heating rate and holding time) on the density of alumina ceramics was performed using the response surface methodology (RSM), based on experimental data obtained according to Box–Behnken experimental design, using the software Design-Expert. From the statistical analysis, linear and nonlinear models with added first-order interaction were developed for prediction and optimization of density-dependent variables: sintering temperature, heating rate and holding time.
Heisenberg Doubles for Snyder-Type Models
Authors: Meljanac Stjepan , Pachoł Anna
Published: June 2021

A Snyder model generated by the noncommutative coordinates and Lorentz generators closes a Lie algebra. The application of the Heisenberg double construction is investigated for the Snyder coordinates and momenta generators. This leads to the phase space of the Snyder model. Further, the extended Snyder algebra is constructed by using the Lorentz algebra, in one dimension higher. The dual pair of extended Snyder algebra and extended Snyder group is then formulated. Two Heisenberg doubles are considered, one with the conjugate tensorial momenta and another with the Lorentz matrices. Explicit formulae for all Heisenberg doubles are given.
Initial Value Problems of Linear Equations with the Dzhrbashyan–Nersesyan Derivative in Banach Spaces
Authors: Fedorov Vladimir E. , Plekhanova Marina V. , Izhberdeeva Elizaveta M.
Published: June 2021

Among the many different definitions of the fractional derivative, the Riemann–Liouville and Gerasimov–Caputo derivatives are most commonly used. In this paper, we consider the equations with the Dzhrbashyan–Nersesyan fractional derivative, which generalizes the Riemann–Liouville and the Gerasimov–Caputo derivatives; it is transformed into such derivatives for two sets of parameters that are, in a certain sense, symmetric. The issues of the unique solvability of initial value problems for some classes of linear inhomogeneous equations of general form with the fractional Dzhrbashyan–Nersesyan derivative in Banach spaces are investigated. An inhomogeneous equation containing a bounded operator at the fractional derivative is considered, and the solution is presented using the Mittag–Leffler functions. The result obtained made it possible to study the initial value problems for a linear inhomogeneous equation with a degenerate operator at the fractional Dzhrbashyan–Nersesyan derivative in the case of relative p-boundedness of the operator pair from the equation. Abstract results were used to study a class of initial boundary value problems for equations with the time-fractional Dzhrbashyan–Nersesyan derivative and with polynomials in a self-adjoint elliptic differential operator with respect to spatial variables.
Deep Deterministic Policy Gradient Algorithm Based on Convolutional Block Attention for Autonomous Driving
Authors: Jin Yanliang , Liu Qianhong , Shen Liquan , Zhu Leiji
Published: June 2021

The research on autonomous driving based on deep reinforcement learning algorithms is a research hotspot. Traditional autonomous driving requires human involvement, and the autonomous driving algorithms based on supervised learning must be trained in advance using human experience. To deal with autonomous driving problems, this paper proposes an improved end-to-end deep deterministic policy gradient (DDPG) algorithm based on the convolutional block attention mechanism, and it is called multi-input attention prioritized deep deterministic policy gradient algorithm (MAPDDPG). Both the actor network and the critic network of the model have the same structure with symmetry. Meanwhile, the attention mechanism is introduced to help the vehicles focus on useful environmental information. The experiments are conducted in the open racing car simulator (TORCS)and the results of five experiment runs on the test tracks are averaged to obtain the final result. Compared with the state-of-the-art algorithm, the maximum reward increases from 62,207 to 116,347, and the average speed increases from 135 km/h to 193 km/h, while the number of success episodes to complete a circle increases from 96 to 147. Also, the variance of the distance from the vehicle to the center of the road is compared, and the result indicates that the variance of the DDPG is 0.6 m while that of the MAPDDPG is only 0.2 m. The above results indicate that the proposed MAPDDPG achieves excellent performance.
Uniqueness of Abel’s Integral Equations of the Second Kind with Variable Coefficients
Authors: Li Chenkuan , Beaudin Joshua
Published: June 2021

This paper studies the uniqueness of the solutions of several of Abel’s integral equations of the second kind with variable coefficients as well as an in-symmetry system in Banach spaces L(Ω) and L(Ω)×L(Ω), respectively. The results derived are new and original, and can be applied to solve the generalized Abel’s integral equations and obtain convergent series as solutions. We also provide a few examples to demonstrate the use of our main theorems based on convolutions, the gamma function and the Mittag–Leffler function.
Acoustic Imaging Using the Built-In Sensors of a Smartphone
Authors: Li Chenming , Wang Junchao , Ding Xinyi , Zhang Naiyin
Published: June 2021

Thanks to the rapid development of the semiconductor industry, smartphones have become an indispensable part of our lives with their increasing computational power, 5G connection, multiple integrated sensors, etc. The boundary of the functionalities of a smartphone is beyond our imagination again and again as the new smartphone is introduced. In this work, we introduce an acoustic imaging algorithm by only using the built-in sensors of a smartphone without any external equipment. First, the speaker of the smartphone is used to emit sound waves with a specific frequency band. During the movement of the smartphone, the accelerometer collects acceleration data to reconstruct the trajectories of the movements, while the microphones receive the reflected waves. A microphone plus an accelerometer are able to partially replace the functionality of a microphone array and to become a symmetry-imitation system. After scanning, a series of algorithms are implemented to generate a heat map, which outlines the target object. Our algorithm demonstrates the feasibility of smartphone-based acoustic imaging with minimal equipment complexity and no additional cost, which is beneficial to the promotion and popularization of acoustic imaging technology in daily applications.
Escherichia coli Shiga Toxins and Gut Microbiota Interactions
Authors: Lee Kyung-Soo , Jeong Yu-Jin , Lee Moo-Seung
Published: June 2021

Escherichia coli (EHEC) and Shigella dysenteriae serotype 1 are enterohemorrhagic bacteria that induce hemorrhagic colitis. This, in turn, may result in potentially lethal complications, such as hemolytic uremic syndrome (HUS), which is characterized by thrombocytopenia, acute renal failure, and neurological abnormalities. Both species of bacteria produce Shiga toxins (Stxs), a phage-encoded exotoxin inhibiting protein synthesis in host cells that are primarily responsible for bacterial virulence. Although most studies have focused on the pathogenic roles of Stxs as harmful substances capable of inducing cell death and as proinflammatory factors that sensitize the host target organs to damage, less is known about the interface between the commensalism of bacterial communities and the pathogenicity of the toxins. The gut contains more species of bacteria than any other organ, providing pathogenic bacteria that colonize the gut with a greater number of opportunities to encounter other bacterial species. Notably, the presence in the intestines of pathogenic EHEC producing Stxs associated with severe illness may have compounding effects on the diversity of the indigenous bacteria and bacterial communities in the gut. The present review focuses on studies describing the roles of Stxs in the complex interactions between pathogenic Shiga toxin-producing E. coli, the resident microbiome, and host tissues. The determination of these interactions may provide insights into the unresolved issues regarding these pathogens.
Toxic Effects of Amanitins: Repurposing Toxicities toward New Therapeutics
Authors: Le Daré Brendan , Ferron Pierre-Jean , Gicquel Thomas
Published: June 2021

The consumption of mushrooms has become increasingly popular, partly due to their nutritional and medicinal properties. This has increased the risk of confusion during picking, and thus of intoxication. In France, about 1300 cases of intoxication are observed each year, with deaths being mostly attributed to Amanita phalloides poisoning. Among amatoxins, α- and β-amanitins are the most widely studied toxins. Hepatotoxicity is the hallmark of these compounds, leading to hepatocellular failure within three days of ingestion. The toxic mechanisms of action mainly include RNA polymerase II inhibition and oxidative stress generation, leading to hepatic cell apoptosis or necrosis depending on the doses ingested. Currently, there is no international consensus concerning Amanita phalloides poisoning management. However, antidotes with antioxidant properties remain the most effective therapeutics to date suggesting the predominant role of oxidative stress in the pathophysiology. The partially elucidated mechanisms of action may reveal a suitable target for the development of an antidote. The aim of this review is to present an overview of the knowledge on amanitins, including the latest advances that could allow the proposal of new innovative and effective therapeutics.
Heat-Labile Toxin from Enterotoxigenic Escherichia coli Causes Systemic Impairment in Zebrafish Model
Authors: Henrique Camila , Falcão Maria Alice Pimentel , De Araújo Pimenta Luciana , Maleski Adolfo Luís Almeida , Lima Carla , Mitsunari Thais , Sampaio Sandra Coccuzzo , Lopes-Ferreira Mônica , Piazza Roxane Maria Fontes
Published: June 2021

Heat-labile toxin I (LT-I), produced by strains of enterotoxigenic Escherichia coli (ETEC), causes profuse watery diarrhea in humans. Different in vitro and in vivo models have already elucidated the mechanism of action of this toxin; however, their use does not always allow for more specific studies on how the LT-I toxin acts in systemic tracts and intestinal cell lines. In the present work, zebrafish (Danio rerio) and human intestinal cells (Caco-2) were used as models to study the toxin LT-I. Caco-2 cells were used, in the 62nd passage, at different cell concentrations. LT-I was conjugated to FITC to visualize its transport in cells, as well as microinjected into the caudal vein of zebrafish larvae, in order to investigate its effects on survival, systemic traffic, and morphological formation. The internalization of LT-I was visualized in 3 × 104 Caco-2 cells, being associated with the cell membrane and nucleus. The systemic traffic of LT-I in zebrafish larvae showed its presence in the cardiac cavity, yolk, and regions of the intestine, as demonstrated by cardiac edema (100%), the absence of a swimming bladder (100%), and yolk edema (80%), in addition to growth limitation in the larvae, compared to the control group. There was a reduction in heart rate during the assessment of larval survival kinetics, demonstrating the cardiotoxic effect of LT-I. Thus, in this study, we provide essential new depictions of the features of LT-I.
Envelope Proteins of Hepatitis B Virus: Molecular Biology and Involvement in Carcinogenesis
Authors: Inoue Jun , Sato Kosuke , Ninomiya Masashi , Masamune Atsushi
Published: June 2021

The envelope of hepatitis B virus (HBV), which is required for the entry to hepatocytes, consists of a lipid bilayer derived from hepatocyte and HBV envelope proteins, large/middle/small hepatitis B surface antigen (L/M/SHBs). The mechanisms and host factors for the envelope formation in the hepatocytes are being revealed. HBV-infected hepatocytes release a large amount of subviral particles (SVPs) containing L/M/SHBs that facilitate escape from the immune system. Recently, novel drugs inhibiting the functions of the viral envelope and those inhibiting the release of SVPs have been reported. LHBs that accumulate in ER is considered to promote carcinogenesis and, especially, deletion mutants in the preS1/S2 domain have been reported to be associated with the development of hepatocellular carcinoma (HCC). In this review, we summarize recent reports on the findings regarding the biological characteristics of HBV envelope proteins, their involvement in HCC development and new agents targeting the envelope.
Quality Assessment and Validation of High-Throughput Sequencing for Grapevine Virus Diagnostics
Authors: Soltani Nourolah , Stevens Kristian A. , Klaassen Vicki , Hwang Min-Sook , Golino Deborah A. , Al Rwahnih Maher
Published: June 2021

Development of High-Throughput Sequencing (HTS), also known as next generation sequencing, revolutionized diagnostic research of plant viruses. HTS outperforms bioassays and molecular diagnostic assays that are used to screen domestic and quarantine grapevine materials in data throughput, cost, scalability, and detection of novel and highly variant virus species. However, before HTS-based assays can be routinely used for plant virus diagnostics, performance specifications need to be developed and assessed. In this study, we selected 18 virus-infected grapevines as a test panel for measuring performance characteristics of an HTS-based diagnostic assay. Total nucleic acid (TNA) was extracted from petioles and dormant canes of individual samples and constructed libraries were run on Illumina NextSeq 500 instrument using a 75-bp single-end read platform. Sensitivity was 98% measured over 264 distinct virus and viroid infections with a false discovery rate (FDR) of approximately 1 in 5 positives. The results also showed that combining a spring petiole test with a fall cane test increased sensitivity to 100% for this TNA HTS assay. To evaluate extraction methodology, these results were compared to parallel dsRNA extractions. In addition, in a more detailed dilution study, the TNA HTS assay described here consistently performed well down to a dilution of 5%. In that range, sensitivity was 98% with a corresponding FDR of approximately 1 in 5. Repeatability and reproducibility were assessed at 99% and 93%, respectively. The protocol, criteria, and performance levels described here may help to standardize HTS for quality assurance and accreditation purposes in plant quarantine or certification programs.
Bacteriophage Encapsulation in pH-Responsive Core-Shell Capsules as an Animal Feed Additive
Authors: Richards Kerry , Malik Danish J.
Published: June 2021

Increasing antibiotic resistance in bacteria that cause zoonotic infections is a major problem for farmers rearing animals for food as well as for consumers who eat the contaminated meat resulting in food-borne infections. Bacteriophages incorporated in animal feed may help reduce carriage and infections in animals including chickens and pigs. There are, however, unmet challenges in protecting phages from processing stresses e.g., during animal feed pelleting operations and during transit of phages through the acidic gastric environment. Core-shell capsules were produced using a concentric nozzle and commercially available encapsulation equipment to fabricate capsules with phages formulated in an oil-in-water microemulsion in the core. pH-responsive capsules released the encapsulated phage cargo within 10–30 min triggered by changes in local environmental pH typically found in the lower gastrointestinal (GI) tract of animals. Acid stability of phages exposed to pH values as low as pH 1 was demonstrated. Encapsulated phages were able to withstand exposure to 95 °C wet heat thermal stress for up to 120 s, conditions typically encountered during feed pellet extrusion processing. Free phages were inactivated within 15 s under these conditions. The present study demonstrates that encapsulation of bacteriophages in core-shell pH-responsive capsules with water-in-oil emulsified phages in the core significantly improves phage viability upon exposure to processing and environmental stresses that require consideration during production of animal feed and application in animals for biocontrol. The results from this study should help guide future development of phage formulations suitable for use in animal feed for animal biocontrol applications.
HIV-1 Persistence in Children during Suppressive ART
Authors: Katusiime Mary Grace , Van Zyl Gert U. , Cotton Mark F. , Kearney Mary F.
Published: June 2021

There is a growing number of perinatally HIV-1-infected children worldwide who must maintain life-long ART. In early life, HIV-1 infection is established in an immunologically inexperienced environment in which maternal ART and immune dynamics during pregnancy play a role in reservoir establishment. Children that initiated early antiretroviral therapy (ART) and maintained long-term suppression of viremia have smaller and less diverse HIV reservoirs than adults, although their proviral landscape during ART is reported to be similar to that of adults. The ability of these early infected cells to persist long-term through clonal expansion poses a major barrier to finding a cure. Furthermore, the effects of life-long HIV persistence and ART are yet to be understood, but growing evidence suggests that these individuals are at an increased risk for developing non-AIDS-related comorbidities, which underscores the need for an HIV cure.
Transduction Enhancers Enable Efficient Human Adenovirus Type 5-Mediated Gene Transfer into Human Multipotent Mesenchymal Stromal Cells
Authors: Nilson Robin , Lübbers Olivia , Weiß Linus , Singh Karmveer , Scharffetter-Kochanek Karin , Rojewski Markus , Schrezenmeier Hubert , Zeplin Philip Helge , Funk Wolfgang , Krutzke Lea , Kochanek Stefan , Kritzinger Astrid
Published: June 2021

Human multipotent mesenchymal stromal cells (hMSCs) are currently developed as cell therapeutics for different applications, including regenerative medicine, immune modulation, and cancer treatment. The biological properties of hMSCs can be further modulated by genetic engineering. Viral vectors based on human adenovirus type 5 (HAdV-5) belong to the most frequently used vector types for genetic modification of human cells in vitro and in vivo. However, due to a lack of the primary attachment receptor coxsackievirus and adenovirus receptor (CAR) in hMSCs, HAdV-5 vectors are currently not suitable for transduction of this cell type without capsid modification. Here we present several transduction enhancers that strongly enhance HAdV-5-mediated gene transfer into both bone marrow- and adipose tissue-derived hMSCs. Polybrene, poly-l-lysine, human lactoferrin, human blood coagulation factor X, spermine, and spermidine enabled high eGFP expression levels in hMSCs. Importantly, hMSCs treated with enhancers were not affected in their migration behavior, which is a key requisite for many therapeutic applications. Exemplary, strongly increased expression of tumor necrosis factor (TNF)-stimulated gene 6 (TSG-6) (a secreted model therapeutic protein) was achieved by enhancer-facilitated HAdV-5 transduction. Thus, enhancer-mediated HAdV-5 vector transduction is a valuable method for the engineering of hMSCs, which can be further exploited for the development of innovative hMSC therapeutics.
Changes in Cell-Mediated Immunity (IFN-γ and Granzyme B) Following Influenza Vaccination
Authors: Otani Naruhito , Nakajima Kazuhiko , Ishikawa Kaori , Ichiki Kaoru , Ueda Takashi , Takesue Yoshio , Yamamoto Takuma , Tanimura Susumu , Shima Masayuki , Okuno Toshiomi
Published: June 2021

Interferon gamma (IFN-γ) is considered a key moderator of cell-mediated immunity. However, little is known about its association with granzyme B, which plays an important role in the effector function of cytotoxic T lymphocytes (CTLs). In the present study, we collected blood samples from 32 healthy adults before and after vaccination with inactivated influenza vaccine in 2017/18 to measure the levels of IFN-γ and granzyme B, which play roles in cell-mediated immunity, and hemagglutination inhibition (HAI) antibody, which plays a role in humoral immunity. The levels of IFN-γ and granzyme B were significantly correlated both before and after vaccination. Furthermore, the post-vaccine fold increases in the IFN-γ and granzyme B levels were significantly correlated. The levels of IFN-γ and granzyme B decreased five months after vaccination in more than half of the subjects who exhibited an increase in IFN-γ and granzyme B at two weeks post-vaccination. This is the first study to investigate the correlation between IFN-γ and granzyme B levels following influenza vaccination. Our study suggests that both IFN-γ and granzyme B can be used as markers of cell-mediated immunity.
When in Need of an ESCRT: The Nature of Virus Assembly Sites Suggests Mechanistic Parallels between Nuclear Virus Egress and Retroviral Budding
Authors: Rose Kevin , Spada Stephanie , Hirsch Vanessa , Bouamr Fadila
Published: June 2021

The proper assembly and dissemination of progeny virions is a fundamental step in virus replication. As a whole, viruses have evolved a myriad of strategies to exploit cellular compartments and mechanisms to ensure a successful round of infection. For enveloped viruses such as retroviruses and herpesviruses, acquisition and incorporation of cellular membrane is an essential process during the formation of infectious viral particles. To do this, these viruses have evolved to hijack the host Endosomal Sorting Complexes Required for Transport (ESCRT-I, -II, and -III) to coordinate the sculpting of cellular membrane at virus assembly and dissemination sites, in seemingly different, yet fundamentally similar ways. For instance, at the plasma membrane, ESCRT-I recruitment is essential for HIV-1 assembly and budding, while it is dispensable for the release of HSV-1. Further, HSV-1 was shown to recruit ESCRT-III for nuclear particle assembly and egress, a process not used by retroviruses during replication. Although the cooption of ESCRTs occurs in two separate subcellular compartments and at two distinct steps for these viral lifecycles, the role fulfilled by ESCRTs at these sites appears to be conserved. This review discusses recent findings that shed some light on the potential parallels between retroviral budding and nuclear egress and proposes a model where HSV-1 nuclear egress may occur through an ESCRT-dependent mechanism.
Modeling within-Host SARS-CoV-2 Infection Dynamics and Potential Treatments
Authors: Sadria Mehrshad , Layton Anita T.
Published: June 2021

The goal of this study was to develop a mathematical model to simulate the actions of drugs that target SARS-CoV-2 virus infection. To accomplish that goal, we have developed a mathematical model that describes the control of a SARS-CoV-2 infection by the innate and adaptive immune components. Invasion of the virus triggers the innate immunity, whereby interferon renders some of the target cells resistant to infection, and infected cells are removed by effector cells. The adaptive immune response is represented by plasma cells and virus-specific antibodies. The model is parameterized and then validated against viral load measurements collected in COVID-19 patients. We apply the model to simulate three potential anti-SARS-CoV-2 therapies: (1) Remdesivir, a repurposed drug that has been shown to inhibit the transcription of SARS-CoV-2, (2) an alternative (hypothetical) therapy that inhibits the virus’ entry into host cells, and (3) convalescent plasma transfusion therapy. Simulation results point to the importance of early intervention, i.e., for any of the three therapies to be effective, it must be administered sufficiently early, not more than a day or two after the onset of symptoms. The model can serve as a key component in integrative platforms for rapid in silico testing of potential COVID-19 therapies and vaccines.
SARS-CoV-2 Antigenemia as a Confounding Factor in Immunodiagnostic Assays: A Case Study
Authors: Belogiannis Konstantinos , Florou Venetia A. , Fragkou Paraskevi C. , Ferous Stefanos , Chatzis Loukas , Polyzou Aikaterini , Lagopati Nefeli , Vassilakos Demetrios , Kittas Christos , Tzioufas Athanasios G. , Tsiodras Sotirios , Sourvinos George , Gorgoulis Vassilis G.
Published: June 2021

Humoral immunity has emerged as a vital immune component against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Nevertheless, a subset of recovered Coronavirus Disease-2019 (COVID-19) paucisymptomatic/asymptomatic individuals do not generate an antibody response, constituting a paradox. We assumed that immunodiagnostic assays may operate under a competitive format within the context of antigenemia, potentially explaining this phenomenon. We present a case where persistent antigenemia/viremia was documented for at least 73 days post-symptom onset using ‘in-house’ methodology, and as it progressively declined, seroconversion took place late, around day 55, supporting our hypothesis. Thus, prolonged SARS-CoV-2 antigenemia/viremia could mask humoral responses, rendering, in certain cases, the phenomenon of ‘non-responders’ a misnomer.
Effect of Infant and Maternal Secretor Status on Rotavirus Vaccine Take—An Overview
Authors: Sharma Sumit , Nordgren Johan
Published: June 2021

Histo-blood group antigens, which are present on gut epithelial surfaces, function as receptors or attachment factors and mediate susceptibility to rotavirus infection. The major determinant for susceptibility is a functional FUT2 enzyme which mediates the presence of α-1,2 fucosylated blood group antigens in mucosa and secretions, yielding the secretor-positive phenotype. Secretors are more susceptible to infection with predominant rotavirus genotypes, as well as to the commonly used live rotavirus vaccines. Difference in susceptibility to the vaccines is one proposed factor for the varying degree of efficacy observed between countries. Besides infection susceptibility, secretor status has been found to modulate rotavirus specific antibody levels in adults, as well as composition of breastmilk in mothers and microbiota of the infant, which are other proposed factors affecting rotavirus vaccine take. Here, the known and possible effects of secretor status in both infant and mother on rotavirus vaccine take are reviewed and discussed.
A Murine CD8+ T Cell Epitope Identified in the Receptor-Binding Domain of the SARS-CoV-2 Spike Protein
Authors: Yang Jihyun , Kim Eunjin , Lee Jong-Soo , Poo Haryoung
Published: June 2021

The ongoing COVID-19 pandemic caused by SARS-CoV-2 has posed a devastating threat worldwide. The receptor-binding domain (RBD) of the spike protein is one of the most important antigens for SARS-CoV-2 vaccines, while the analysis of CD8 cytotoxic T lymphocyte activity in preclinical studies using mouse models is critical for evaluating vaccine efficacy. Here, we immunized C57BL/6 wild-type mice and transgenic mice expressing human angiotensin-converting enzyme 2 (ACE2) with the SARS-CoV-2 RBD protein to evaluate the IFN-γ-producing T cells in the splenocytes of the immunized mice using an overlapping peptide pool by an enzyme-linked immunospot assay and flow cytometry. We identified SARS-CoV-2 S395–404 as a major histocompatibility complex (MHC) class I-restricted epitope for the RBD-specific CD8 T cell responses in C57BL/6 mice.