bluuebunny/crossref_metadata_2025 huggingface dataset:
Gut Microbiota and COVID-19: Potential Implications for Disease Severity
Authors: Rocchi Giulia , Giovanetti Marta , Benedetti Francesca , Borsetti Alessandra , Ceccarelli Giancarlo , Zella Davide , Altomare Annamaria , Ciccozzi Massimo , Guarino Michele Pier Luca
Published: September 2022

The SARS-CoV-2 pandemic resulted in an unprecedented global crisis. SARS-CoV-2 primarily causes lung infection trough the binding of the virus with the ACE-2 cell receptor located on the surface of the alveolar epithelial cells. Notably, ACE-2 cell receptors are also expressed in the epithelial cells of the intestinal tract (GI). Recent data showed that the microbial communities of the GI might act as local and systematic inflammatory modulators. Gastrointestinal symptoms, including diarrhea, are frequently observed in infected individuals, and recent released data indicate that SARS-CoV-2 may also spread by fecal–oral transmission. Moreover, the gut microbiota’s ecosystem can regulate and be regulated by invading pathogens, including viruses, facilitating an effective immune response, which in turn results in less severe diseases. In this regard, increased SARS-CoV-2 mortality and morbidities appear to be frequently observed in elderly immunocompromised patients and in people with essential health problems, such as diabetes, who, indeed, tend to have a less diverse gut microbiota (dysbiosis). Therefore, it is important to understand how the interaction between the gut microbiota and SARS-CoV-2 might shape the intensity of the infection and different clinical outcomes. Here, we provide insights into the current knowledge of dysbiosis during SARS-CoV-2 infection and methods that may be used to re-establish a more correct microbiota composition.
Failure of an Approximately Six Week Course of Tafenoquine to Completely Eradicate Babesia microti Infection in an Immunocompromised Patient
Authors: Prasad Prithiv J. , Wormser Gary P.
Published: September 2022

Although tafenoquine was highly effective for eliminating microscopically detectable parasitemia in mouse models of Babesia microti infection, all of the mice which were assessed developed a relapse of infection, except for those which had been treated concomitantly with artesunate. We report an immunocompromised patient with a similar relapse of parasitemia despite a 46-day course of tafenoquine treatment. More data on whether a longer duration of tafenoquine treatment or using a higher maintenance dose, versus adding a second drug to the regimen, will prevent relapse when tafenoquine is used to treat a highly immunocompromised patient with babesiosis should be investigated.
Detection of Lotmaria passim and Crithidia mellificae in Selected Bumblebee Species
Authors: Michalczyk Maria , Sokół Rajmund
Published: September 2022

Bumblebees (Bombus spp.) are an essential element of the ecosystem and the global economy. They are valued pollinators in many countries around the word. Unfortunately, there has been a decline in the bumblebee population, which is attributed to, among others, pathogens and reduced access to food due to the loss of natural nesting sites. Lotmaria passim and Crithidia mellificae, protozoan pathogens of the family Trypanosomatidae, commonly infect bumblebees, including in Poland. In this study, a Polish population of bumblebees was screened for L. passim and C. mellificae. The experiment was performed on 13 adult bumblebees belonging to 4 species: B. lapidarius, B. lucorum, B. pascuorum, and B. terrestris. Protozoa of the family Trypanosomatidae were identified by PCR. Only L. passim was identified in one B. pascuorum individual. Further research is needed to confirm the effect of concurrent pathogens on the decline of bumblebee populations.
Characteristics of COVID-19 Infection in a Hospitalized Autoimmune Hepatitis Patient
Authors: da Costa Vanessa Duarte , Wiggers Wilian Jean , Ivantes Claudia Alexandra Pontes , da Fonseca Rodrigo Jardim Monteiro , Dávila Alberto Martín Rivera , Moreira Otacilio C. , Ferreira Beatriz Iandra da Silva , de Paula Vanessa Salete , da Silva Lucas Lima , Santos Alanna Calheiros , Villar Livia Melo
Published: September 2022

The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), has become a major public health worldwide. Hepatic dysfunction has been seen in patients with COVID-19 and could be related to a viral cytopathic effect, an exacerbated immune reaction, or drug-induced liver damage. Currently, routine modification of immunosuppressive therapy in patients with autoimmune hepatitis (AIH) before and after SARS-CoV-2 infection remains an important topic to be discussed. However, there is little evidence about this thematic to support any recommendation. Here, we described a case report in which the use of an immunosuppressive drug by a patient with diagnosed AIH might have influenced the COVID-19 clinical course with altered laboratory hematological and biochemical parameters during infection.
Pharmacological Potential of Flavonoids against Neurotropic Viruses
Authors: Castro e Silva Juliana Helena , Souza Jéssica Teles , Schitine Clarissa , Júnior Aníbal de Freitas Santos , Bastos Eduardo Muniz Santana , Costa Silvia Lima
Published: September 2022

Flavonoids are a group of natural compounds that have been described in the literature as having anti-inflammatory, antioxidant, and neuroprotective compounds. Although they are considered versatile molecules, little has been discussed about their antiviral activities for neurotropic viruses. Hence, the present study aimed to investigate the pharmacological potential of flavonoids in the face of viruses that can affect the central nervous system (CNS). We carried out research from 2011 to 2021 using the Pubmed platform. The following were excluded: articles not in the English language, letters to editors, review articles and papers that did not include any experimental or clinical tests, and papers that showed antiviral activities against viruses that do not infect human beings. The inclusion criteria were in silico predictions and preclinical pharmacological studies, in vitro, in vivo and ex vivo, and clinical studies with flavonoids, flavonoid fractions and extracts that were active against neurotropic viruses. The search resulted in 205 articles that were sorted per virus type and discussed, considering the most cited antiviral activities. Our investigation shows the latest relevant data about flavonoids that have presented a wide range of actions against viruses that affect the CNS, mainly influenza, hepatitis C and others, such as the coronavirus, enterovirus, and arbovirus. Considering that these molecules present well-known anti-inflammatory and neuroprotective activities, using flavonoids that have demonstrated both neuroprotective and antiviral effects could be viewed as an alternative for therapy in the course of CNS infections.
Xylan Prebiotics and the Gut Microbiome Promote Health and Wellbeing: Potential Novel Roles for Pentosan Polysulfate
Authors: Smith Margaret M. , Melrose James
Published: September 2022

This narrative review highlights the complexities of the gut microbiome and health-promoting properties of prebiotic xylans metabolized by the gut microbiome. In animal husbandry, prebiotic xylans aid in the maintenance of a healthy gut microbiome. This prevents the colonization of the gut by pathogenic organisms obviating the need for dietary antibiotic supplementation, a practice which has been used to maintain animal productivity but which has led to the emergence of antibiotic resistant bacteria that are passed up the food chain to humans. Seaweed xylan-based animal foodstuffs have been developed to eliminate ruminant green-house gas emissions by gut methanogens in ruminant animals, contributing to atmospheric pollution. Biotransformation of pentosan polysulfate by the gut microbiome converts this semi-synthetic sulfated disease-modifying anti-osteoarthritic heparinoid drug to a prebiotic metabolite that promotes gut health, further extending the therapeutic profile and utility of this therapeutic molecule. Xylans are prominent dietary cereal components of the human diet which travel through the gastrointestinal tract as non-digested dietary fibre since the human genome does not contain xylanolytic enzymes. The gut microbiota however digest xylans as a food source. Xylo-oligosaccharides generated in this digestive process have prebiotic health-promoting properties. Engineered commensal probiotic bacteria also have been developed which have been engineered to produce growth factors and other bioactive factors. A xylan protein induction system controls the secretion of these compounds by the commensal bacteria which can promote gut health or, if these prebiotic compounds are transported by the vagal nervous system, may also regulate the health of linked organ systems via the gut–brain, gut–lung and gut–stomach axes. Dietary xylans are thus emerging therapeutic compounds warranting further study in novel disease prevention protocols.
Chiral Biomaterials for Nanomedicines: From Molecules to Supraparticles
Authors: Jung Wookjin , Kwon Junyoung , Cho Wonjoon , Yeom Jihyeon
Published: September 2022

Chirality, the property whereby an object or a system cannot be superimposed on its mirror image, prevails amongst nature over various scales. Especially in biology, numerous chiral building blocks and chiral-specific interactions are involved in many essential biological activities. Despite the prevalence of chirality in nature, it has been no longer than 70 years since the mechanisms of chiral-specific interactions drew scientific attention and began to be studied. Owing to the advent of chiral-sensitive equipment such as circular dichroism spectrometers or chiral liquid columns for chromatography, it has recently been possible to achieve a deeper understanding of the chiral-specific interactions and consequential impacts on the functionality and efficiency of nanomedicine. From this point of view, it is worthwhile to examine previously reported chiral biomaterials with their compositions and possible applications to achieve new paradigms of biomaterials. This review discusses chiral materials on various scales and their biological applications.
ReDDLE-Net: Reflectance Decomposition for Directional Light Estimation
Authors: Yang Jiangxin , Ding Binjie , He Zewei , Pan Gang , Cao Yanpeng , Cao Yanlong , Zheng Qian
Published: September 2022

The surfaces of real objects can visually appear to be glossy, matte, or anywhere in between, but essentially, they display varying degrees of diffuse and specular reflectance. Diffuse and specular reflectance provides different clues for light estimation. However, few methods simultaneously consider the contributions of diffuse and specular reflectance for light estimation. To this end, we propose ReDDLE-Net, which performs Reflectance Decomposition for Directional Light Estimation. The primary idea is to take advantage of diffuse and specular clues and adaptively balance the contributions of estimated diffuse and specular components for light estimation. Our method achieves a superior performance advantage over state-of-the-art directional light estimation methods on the DiLiGenT benchmark. Meanwhile, the proposed ReDDLE-Net can be combined with existing calibrated photometric stereo methods to handle uncalibrated photometric stereo tasks and achieve state-of-the-art performance.
An Optical Front-End for Wideband Transceivers Based on Photonic Time Compression and Stretch
Authors: Zhang Yukang , Chi Hao
Published: September 2022

This study proposes an optical front-end for wideband transceivers based on photonic time compression (PTC) and photonic time stretch (PTS) techniques. The PTC and PTS systems within a transceiver generate and receive wideband RF signals, respectively, which expand the processible signal bandwidth. We present analytical models for characterizing the optical front-end based on the PTC and PTS. The design of the front-end for signal generation and reception is also discussed, in which we emphasize the bandwidth match between the PTC-based transmitter and PTS-based receiver through an appropriate dispersion configuration. We conducted experiments on PTC and PTS systems with a single channel. Further simulation results for PTC and PTS systems with multiple channels for continuous-time operation are presented. The proposed front-end based on time compression/stretch can largely improve the signal bandwidth in systems using inexpensive low-speed analogue/digital converters.
Evaluation of the Efficacy of Cryopreserved Human Umbilical Cord Tissue Allografts to Augment Functional and Pain Outcome Measures in Patients with Knee Osteoarthritis: An Observational Data Collection Study
Authors: Davis Justine M. , Sheinkop Mitchell B. , Barrett Tyler C.
Published: September 2022

The primary objective of this study is to report the initial efficacy data observed with the use of cryopreserved human umbilical tissue allografts for supplementation in patients with symptomatic degeneration of load-bearing articular cartilage in the knee joint. Our primary endpoints were pain, stiffness, and functional recovery scores. In this ongoing study, 55 participants (age 56–93 years) received a single Wharton’s jelly tissue allograft application. The study dose consisted of 150 mg of Wharton’s jelly allograft suspended in approximately 2 mL of sterile sodium chloride 0.9% solution (normal saline). Each study knee application was performed under ultrasound guidance in a physician’s office. The research methodology consisted of Numeric Pain Rating Scale (NPRS) scores and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) subsection scores including pain, stiffness, and physical function. Study enrollment consisted of 55 patients followed for a post-application duration of 90 days. No adverse events or adverse reactions were reported. The results demonstrated statistically significant improvements of NPRS and WOMAC in initial versus 90-day examination. The data represent Wharton’s jelly tissue allograft applications are safe, non-surgical, and efficacious for patients with symptomatic osteoarthritis of the knee.
Performance and Genetic Parameters of Poplar Hybrids and Clones in a Field Trial Are Modified by Contrasting Environmental Conditions during the Vegetative Propagation Phase
Authors: Gudynaitė-Franckevičienė Valda , Pliūra Alfas
Published: September 2022

This study investigates epigenetics-like phenomena: how performance phenotypic plasticity, genotypic variation, and the heritability of growth traits and total phenolic compounds of Populus hybrids and clones in field trials may be modified by contrasting temperature conditions at their vegetation propagation phase. The significant effect of rooting–growing conditions on further tree performance in field trials was found for height increment in 2020, although the interaction hybrid by rooting–growing conditions was highly significant for phenolic compounds, tree height, and diameter, meaning that the performance of some hybrids was affected by rooting–growing conditions, thus demonstrating epigenetic-like effects. For phenolic compounds, interactions were also significant at the clonal level. High estimates of ecovalency indicate that some hybrids are ecologically sensitive, and epigenetic-like phenomena might occur. Hybrid P. balsamifera × P. trichocarpa is characterized by high ecovalency and specific adaptations according to mean tree height when vegetatively propagated under different rooting–growing conditions. Low estimates of P. deltoides × P. trichocarpa ecovalency demonstrate a general adaptation according to mean tree height in a field trial. Vegetative propagation conditions have also altered the genetic variation of traits in trees being planted in field trials.
Silver Nanoparticle Effects on Antioxidant Response in Tobacco Are Modulated by Surface Coating
Authors: Košpić Karla , Biba Renata , Peharec Štefanić Petra , Cvjetko Petra , Tkalec Mirta , Balen Biljana
Published: September 2022

The antimicrobial properties of silver and enhanced reactivity when applied in a nanoparticle form (AgNPs) led to their growing utilization in industry and various consumer products, which raises concerns about their environmental impact. Since AgNPs are prone to transformation, surface coatings are added to enhance their stability. AgNP phytotoxicity has been mainly attributed to the excess generation of reactive oxygen species (ROS), leading to the induction of oxidative stress. Herein, in vitro-grown tobacco (Nicotiana tabacum) plants were exposed to AgNPs stabilized with either polyvinylpyrrolidone (PVP) or cetyltrimethylammonium bromide (CTAB) as well as to ionic silver (AgNO3), applied in the same concentrations, either alone or in combination with cysteine, a strong silver ligand. The results show a higher accumulation of Ag in roots and leaves after exposure to AgNPs compared to AgNO3. This was correlated with a predominantly higher impact of nanoparticle than ionic silver form on parameters of oxidative stress, although no severe damage to important biomolecules was observed. Nevertheless, all types of treatments caused mobilization of antioxidant machinery, especially in leaves, although surface coatings modulated the activation of its specific components. Most effects induced by AgNPs or AgNO3 were alleviated with addition of cysteine.
Single and Associated Effects of Drought and Heat Stresses on Physiological, Biochemical and Antioxidant Machinery of Four Eggplant Cultivars
Authors: Hannachi Sami , Signore Angelo , Adnan Mohd , Mechi Lassaad
Published: September 2022

The impact of heat and drought stresses, either individually or combined, on physiological and biochemical parameters of four eggplant varieties (Solanum melongena L.) was investigated. The results showed that associated stress generated the highest increment in proline content, MDA concentration, and H2O2 accumulation and generated the lowest increment in RWC. In addition, ‘Bonica’ and ‘Galine’ exhibited higher starch accumulation and lower electrolyte leakage (EL) under combined stress. Moreover, drought and heat stresses applied individually contributed to a substantial decline in Chla, Chlb, total Chl, Chla/b, and carotenoids (p > 0.05) in ‘Adriatica’ and ‘Black Beauty’. The decreasing level of pigments was more substantial under associated drought and heat stresses. The simultaneous application of drought and heat stresses reduced PSII efficiency (Fv/Fm), quantum yield (ΦPSII), and photochemical efficiency (qp) and boosted non-photochemical quenching (NPQ) levels. However, the change recorded in the chlorophyll fluorescence parameters was less pronounced in ‘Bonica’ and ‘Galine’. In addition, the gas exchange parameters, transpiration rate (E), CO2 assimilation rate (A), and net photosynthesis (Pn) were decreased in all varieties under all stress conditions. However, the reduction was more pronounced in ‘Adriatica’ and ‘Black Beauty’. Under associated stress, antioxidant enzymes, SOD, APX, CAT, and GR exhibited a significant increment in all eggplant cultivars. However, the rising was more elevated in ‘Bonica’ and ‘Galine’ (higher than threefold increase) than in ‘Adriatica’ and ‘Black Beauty’ (less than twofold increase). Furthermore, ‘Bonica’ and ‘Galine’ displayed higher non-enzyme scavenging activity (AsA and GSH) compared to ‘Adriatica’ and ‘Black Beauty’ under associated stress. Under stressful conditions, nutrient uptake was affected in all eggplant cultivars; however, the root, stem, and leaf N, P, and K contents, in ‘Adriatica’ and ‘Black Beauty’ were lower than in ‘Bonica’ and ‘Galine’, thereby showing less capacity in accumulating nutrients. The coexistence of drought and heat stresses caused more damage on eggplant varieties than the single appearance of drought or heat stress separately. ‘Bonica’ and ‘Galine’ showed better distinguished performance compared to ‘Adriatica’ and ‘Black Beauty’. The superiority of ‘Bonica’ and ‘Galine’ in terms of tolerance to heat and drought stresses was induced by more effective antioxidant scavenging potential, enhanced osmolyte piling-up, and prominent ability in keeping higher photosynthetic efficiency and nutrient equilibrium compared with ‘Adriatica’ and ‘Black Beauty’.
Rapid Quantification Method for Yield, Calorimetric Energy and Chlorophyll a Fluorescence Parameters in Nicotiana tabacum L. Using Vis-NIR-SWIR Hyperspectroscopy
Authors: Falcioni Renan , Moriwaki Thaise , Antunes Werner Camargos , Nanni Marcos Rafael
Published: September 2022

High-throughput and large-scale data are part of a new era of plant remote sensing science. Quantification of the yield, energetic content, and chlorophyll a fluorescence (ChlF) remains laborious and is of great interest to physiologists and photobiologists. We propose a new method that is efficient and applicable for estimating photosynthetic performance and photosystem status using remote sensing hyperspectroscopy with visible, near-infrared and shortwave spectroscopy (Vis-NIR-SWIR) based on rapid multivariate partial least squares regression (PLSR) as a tool to estimate biomass production, calorimetric energy content and chlorophyll a fluorescence parameters. The results showed the presence of typical inflections associated with chemical and structural components present in plants, enabling us to obtain PLSR models with R2P and RPDP values greater than >0.82 and 3.33, respectively. The most important wavelengths were well distributed into 400 (violet), 440 (blue), 550 (green), 670 (red), 700–750 (red edge), 1330 (NIR), 1450 (SWIR), 1940 (SWIR) and 2200 (SWIR) nm operating ranges of the spectrum. Thus, we report a methodology to simultaneously determine fifteen attributes (i.e., yield (biomass), ΔH°area, ΔH°mass, Fv/Fm, Fv’/Fm’, ETR, NPQ, qP, qN, ΦPSII, P, D, SFI, PI(abs), D.F.) with high accuracy and precision and with excellent predictive capacity for most of them. These results are promising for plant physiology studies and will provide a better understanding of photosystem dynamics in tobacco plants when a large number of samples must be evaluated within a short period and with remote acquisition data.
Combined Impact of Excess Zinc and Cadmium on Elemental Uptake, Leaf Anatomy and Pigments, Antioxidant Capacity, and Function of Photosynthetic Apparatus in Clary Sage (Salvia sclarea L.)
Authors: Dobrikova Anelia , Apostolova Emilia , Adamakis Ioannis-Dimosthenis S. , Hanć Anetta , Sperdouli Ilektra , Moustakas Michael
Published: September 2022

Clary sage (Salvia sclarea L.) is a medicinal plant that has the potential to be used for phytoextraction of zinc (Zn) and cadmium (Cd) from contaminated soils by accumulating these metals in its tissues. Additionally, it has been found to be more tolerant to excess Zn than to Cd stress alone; however, the interactive effects of the combined treatment with Zn and Cd on this medicinal herb, and the protective strategies of Zn to alleviate Cd toxicity have not yet been established in detail. In this study, clary sage plants grown hydroponically were simultaneously exposed to Zn (900 µM) and Cd (100 μM) for 8 days to obtain more detailed information about the plant responses and the role of excess Zn in mitigating Cd toxicity symptoms. The leaf anatomy, photosynthetic pigments, total phenolic and anthocyanin contents, antioxidant capacity (by DPPH and FRAP analyses), and the uptake and distribution of essential elements were investigated. The results showed that co-exposure to Zn and Cd leads to an increased leaf content of Fe and Mg compared to the control, and to increased leaf Ca, Mn, and Cu contents compared to plants treated with Cd only. This is most likely involved in the defense mechanisms of excess Zn against Cd toxicity to protect the chlorophyll content and the functions of both photosystems and the oxygen-evolving complex. The data also revealed that the leaves of clary sage plants subjected to the combined treatment have an increased antioxidant capacity attributed to the higher content of polyphenolic compounds. Furthermore, light microscopy indicated more alterations in the leaf morphology after Cd-only treatment than after the combined treatment. The present study shows that excess Zn could mitigate Cd toxicity in clary sage plants.
Cellulose in Foliage and Changes during Seasonal Leaf Development of Broadleaf and Conifer Species
Authors: Kern Zoltan , Kimak Adam , Hatvani István Gábor , Llanos Campana Daniela Maria , Leuenberger Markus
Published: September 2022

Stable isotope approaches are widely applied in plant science and many improvements made in the field focus on the analysis of specific components of plant tissues. Although technical developments have been very beneficial, sample collection and preparation are still very time and labor-consuming. The main objective of this study was to create a qualitative dataset of alpha-cellulose content of leaf tissues of arboreal species. We extracted alpha-cellulose from twelve species: Abies alba Mill., Acer pseudoplatanus L., Fagus sylvatica L., Larix decidua Mill., Picea abies (L.) Karst., Pinus sylvestris L., Quercus cerris L., Quercus petrea (Matt.) Liebl., Quercus pubescens Wild., Quercus robur L., Tilia platyphyllos Scop. and Ulmus glabra Huds. While these species show an increase in cellulose yield from bud break to full leaf development, the rates of increase in cellulose content and the duration of the juvenile phase vary greatly. Moreover, the veins display significantly higher alpha-cellulose content (4 to 11%) compared to blade tissues, which reflects their different structural and biochemical functions. A guide for the mass of sample material required to yield sufficient alpha-cellulose for a standard stable isotope analysis is presented. The additional benefits of the assessment of the mass of required sample material are reduced sample preparation time and its usefulness in preparing samples of limited availability (e.g., herbarium material, fossil samples).
Determining Reproductive Parameters, which Contribute to Variation in Yield of Olive Trees from Different Cultivars, Irrigation Regimes, Age and Location
Authors: Wechsler Tahel , Bakhshian Ortal , Engelen Chaim , Dag Arnon , Ben-Ari Giora , Samach Alon
Published: September 2022

Olive (Olea europaea L.) trees can reach a very old age and still bear fruit. Although traditional groves are planted at low density and are rainfed, many newer groves are planted at higher densities and irrigated. As expected, initial yields per area are larger in high density plantations, yet some farmers claim they experience a reduction in productivity with grove age, even in well maintained trees. In order to test the accuracy of this claim and its underlying cause, we measured several productivity parameters in selected branches of trees in seven sites differing in cultivar (‘Barnea’ or ‘Souri’), location and irrigation regime (rainfed or irrigated) for two consecutive years. For each site (cultivar/location/regime), we compared neighboring groves of different ages, altogether 14 groves. There was no consistent reduction in productivity in older groves. Differences in productivity between irrigated cultivars were mostly due to variation in the percentage of inflorescences that formed fruit. Several parameters were higher in irrigated, compared to rainfed ‘Souri’. Differences in productivity between years within the same grove was mostly due to variation in the percentage of nodes forming inflorescences. We studied the expression of OeFT2 encoding a FLOWERING LOCUS T protein involved in olive flower induction in leaves of trees of different ages, including juvenile seedlings. Expression increased during winter in mature trees and correlated with the percentage of inflorescences formed. The leaves of juvenile seedlings expressed higher levels of two genes encoding APETALA2-like proteins, potential inhibitors of OeFT2 expression. The buds of juvenile seedlings expressed higher levels of OeTFL1, encoding a TERMINAL FLOWER 1 protein, a potential inhibitor of OeFT2 function in the meristem. Our results suggest that olives, once past the juvenile phase, can retain a similar level of productivity even in densely planted well maintained groves.
The Effect of Solvent Hydrophilicity on the Enzymatic Ring-Opening Polymerization of L-Lactide by Candida rugosa Lipase
Authors: Curie Catia Angli , Darmawan Muhammad Arif , Dianursanti Dianursanti , Budhijanto Wiratni , Gozan Misri
Published: September 2022

Contradictions have been reported on the effect of organic solvents, especially toluene, on enzymatic ring-opening polymerization (eROP) of L-lactide. Studies have shown that log P, a common measure of hydrophilicity, affects enzyme activity. This study examines the effect of solvents with various log P values on the eROP of L-lactide, performed using Candida rugosa lipase (CRL). N,N-dimethylacetamide (DMA), 1,2-dimethoxybenzene, 1,4-dimethoxybenzene, diphenyl ether, and dodecane were used as the organic solvents. The eROP in ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]) was also conducted to compare its performance with the organic solvents. The results show that [BMIM][PF6]-mediated eROP gave better conversion and molecular weight than the organic solvent-mediated eROP. In this study, the effects of solvents hydrophilicity are discussed, including the possibility of hexafluorophosphate ion ([PF6]−) hydrolysis to occur.
Activation Mechanism of Coal Gangue and Its Impact on the Properties of Geopolymers: A Review
Authors: Han Ruicong , Guo Xiaoning , Guan Junfeng , Yao Xianhua , Hao Ying
Published: September 2022

Coal gangue is one of the industrial solid wastes that may harm the human body through the ecosystem for a long time. Using coal gangue in geopolymer preparation can effectively reduce cement output and meet the sustainability requirements. In this paper, the physical and chemical characteristics, including the heavy metal content, of coal gangue from different producing areas are described. Then, the mechanism of physical activation (mechanical and thermal activation), chemical activation, and compound activation of coal gangue are illustrated. The machinability, as well as the mechanical, microscopic, and toxicity consolidation properties of geopolymers prepared from coal gangue, are summarized and analyzed. The results indicate that the coal gangue geopolymers can have higher mobility and mechanical strength than cement-based composites by adjusting high calcium element material, alkali activator content, Na2SiO3 modulus, and curing condition. After physical activation, coal gangue is used in geopolymer preparation with a chemical activator (alkali excitation agent), which effectively forms a three-dimensional silicon aluminate polymer network. The pore structure is dense, the physical fixation and chemical bonding are strengthened, and the solidification and adsorption of heavy metal ions are improved. Further, it can also be applied to solidifying radioactive waste, which is following the future development direction.
Comparison of Titanium and PEEK Medical Plastic Implant Materials for Their Bacterial Biofilm Formation Properties
Authors: Sarfraz Sonia , Mäntynen Pilvi-Helinä , Laurila Marisa , Rossi Sami , Leikola Junnu , Kaakinen Mika , Suojanen Juho , Reunanen Justus
Published: September 2022

This study investigated two of the most commonly used CAD–CAM materials for patient-specific reconstruction in craniomaxillofacial surgery. The aim of this study was to access the biofilm formation of Staphylococcus aureus, Streptococcus mutans, Enterococcus faecalis, and Escherichia coli on titanium and PEEK medical implant materials. Two titanium specimens (titanium grade 2 tooled with a Planmeca CAD–CAM milling device and titanium grade 5 tooled with a computer-aided design direct metal laser sintering device (CAD-DMLS)) and one PEEK specimen tooled with a Planmeca CAD–CAM milling device were studied. Bacterial adhesion on implants was evaluated in two groups (saliva-treated group and non-saliva-treated group) to imitate intraoral and extraoral surgical routes for implant placement. The PEEK medical implant material showed higher bacterial adhesion by S. aureus, S. mutans, and E. coli than titanium grade 2 and titanium grade 5, whereas E. faecalis showed higher adhesion to titanium as compared to PEEK. Saliva contamination of implants also effected bacterial attachment. Salivary coating enhanced biofilm formation by S. aureus, S. mutans, and E. faecalis. In conclusion, our findings imply that regardless of the implant material type or tooling techniques used, salivary coating plays a vital role in bacterial adhesion. In addition, the majority of the bacterial strains showed higher adhesion to PEEK than titanium.
Interfacial Forces in Free-Standing Layers of Melted Polyethylene, from Critical to Nanoscopic Thicknesses
Authors: Ramírez-Zavaleta Fernando Iguazú , Torres-Dominguez Victor Manuel , Viramontes-Gamboa Gonzalo , Rivera José Luis
Published: September 2022

Molecular dynamics simulations of ultrathin free-standing layers made of melted (373.15–673.15 K) polyethylene chains, which exhibit a lower melting temperature (compared to the bulk value), were carried out to investigate the dominant pressure forces that shape the conformation of chains at the interfacial and bulk liquid regions. We investigated layer thicknesses, tL, from the critical limit of mechanical stability up to lengths of tens of nm and found a normal distribution of bonds dominated by slightly stretched chains across the entire layer, even at large temperatures. In the bulk region, the contribution of bond vibrations to pressure was one order of magnitude larger than the contributions from interchain interactions, which changed from cohesive to noncohesive at larger temperatures just at a transition temperature that was found to be close to the experimentally derived onset temperature for thermal stability. The interchain interactions produced noncohesive interfacial regions at all temperatures in both directions (normal and lateral to the surface layer). Predictions for the value of the surface tension, γ, were consistent with experimental results and were independent of tL. However, the real interfacial thickness—measured from the outermost part of the interface up to the point where γ reached its maximum value—was found to be dependent on tL, located at a distance of 62 Å from the Gibbs dividing surface in the largest layer studied (1568 chains or 313,600 bins); this was ~4 times the length of the interfacial thickness measured in the density profiles.
An Effective Method for Working Fluid Design of Organic Rankine Cycle
Authors: Tang Jianping , Kang Lixia , Liu Yongzhong
Published: September 2022

This paper addresses an effective method for the selection and design of optimal working fluids of organic Rankine cycle (ORC) based on quantitative working fluid selection rules, aiming to reduce the complexity and improve the calculation efficiency of the working fluid design model. In the proposed method, the critical properties of the optimal working fluids for the given heat sources are first explored and summarized based on the quantitative relationship obtained by existing research and simulations. Based on the concept of working fluid substitution, the critical properties of the optimal pure working fluid are then adopted to target the optimal mixture working fluid by solving a modified computer-aided molecular-mixture design (CAMD) model and the ratio r of critical pressure to critical temperature is also strictly constrained to ensure a better working fluid. The component and the composition of the mixture working fluid are, thus, determined simultaneously. Results showed that both the designed pure and mixture working fluids have better performance than the existing ones determined by the selection and design rules. The targeted mixture working fluid enables one to achieve at least similar systematic efficiency and a better exergy efficiency in ORC than pure working fluid featuring similar critical properties. The application of the proposed method and model is finally verified via a practical case study.
Post-Traumatic Stress Disorder among Funeral Directors after the First Wave of COVID-19 in Belgium
Authors: Van Overmeire Roel , Vesentini Lara , Bilsen Johan
Published: September 2022

(1) Background: Studies have shown that healthcare workers have an increased chance of developing post-traumatic stress symptoms (PTSS) during the COVID-19 pandemic. However, funeral directors have not yet been studied, despite facing many of the same possible causes of PTSS as healthcare workers. (2) Methods: An online survey was spread to directors of funeral home organization DELA in Belgium (n = 287). The validated scale PCL-5 was used to assess PTSS. Additionally, fear of being infected, fear of infecting family or friends and demographic factors (age, gender, living situations, work experience) were asked. Respondents were asked to indicate if they thought of the COVID-19 period when completing the PCL-5. In addition, with a self-made question, respondents were also asked to compare their current stress-levels with those before COVID-19. (3) Results: 107 respondents were included in the study. Thirteen respondents were above the threshold for possible PTSD-diagnosis, but only four fulfilled the criteria of completing the PCL-5 with COVID-19 in mind. PTSS-scores were significantly associated with a fear of being infected (p = 0.006). Almost a majority (49.5%) of the respondents felt more stress during the period of completing the survey than the period before COVID-19, though 33.6% felt no change. (4) Conclusions: Though the PTSS-symptom rates were lower than for healthcare workers, this study does show that there should be attention for the mental health of funeral directors in the aftermath of COVID-19.
Or, The Modern God: Biblical Allusions in Mary Shelley’s Frankenstein
Authors: Kawashima Robert S.
Published: September 2022

Mary Shelley’s Frankenstein is largely organized around its explicit reference to Milton’s retelling of Genesis 2–3, Paradise Lost. Unfortunately, this reference to Milton has discouraged scholars from going back to the Old Testament itself. In fact, the novel contains three crucial biblical allusions. Most obvious, of course, are the allusions to creation (Genesis 1–3), which contain details not found in Milton’s epic. The biblically literate reader will be able to discern two more crucial biblical allusions: one to Exodus 32–33 and the other to the Book of Job. In both of these texts, we find a man—Moses and Job, respectively—seeking an audience with his creator, such as that Adam and Eve enjoyed in the garden.
Climate Sensitivity of the Arid Scrublands on the Tibetan Plateau Mediated by Plant Nutrient Traits and Soil Nutrient Availability
Authors: Chen Ben , Chen Hui , Li Meng , Fiedler Sebastian , Mărgărint Mihai Ciprian , Nowak Arkadiusz , Wesche Karsten , Tietjen Britta , Wu Jianshuang
Published: September 2022

Climate models predict the further intensification of global warming in the future. Drylands, as one of the most fragile ecosystems, are vulnerable to changes in temperature, precipitation, and drought extremes. However, it is still unclear how plant traits interact with soil properties to regulate drylands’ responses to seasonal and interannual climate change. The vegetation sensitivity index (VSI) of desert scrubs in the Qaidam Basin (NE Tibetan Plateau) was assessed by summarizing the relative contributions of temperature (SGST), precipitation (SGSP), and drought (temperature vegetation dryness index, STVDI) to the dynamics of the normalized difference vegetation index (NDVI) during plant growing months yearly from 2000 to 2015. Nutrient contents, including carbon, nitrogen, phosphorus, and potassium in topsoils and leaves of plants, were measured for seven types of desert scrub communities at 22 sites in the summer of 2016. Multiple linear and structural equation models were used to reveal how leaf and soil nutrient regimes affect desert scrubs’ sensitivity to climate variability. The results showed that total soil nitrogen (STN) and leaf carbon content (LC), respectively, explained 25.9% and 17.0% of the VSI variance across different scrub communities. Structural equation modeling (SEM) revealed that STN and total soil potassium (STK) mediated desert scrub’s VSI indirectly via SGST (with standardized path strength of −0.35 and +0.32, respectively) while LC indirectly via SGST and SGSP (with standardized path strength of −0.31 and −0.19, respectively). Neither soil nor leave nutrient contents alone could explain the VSI variance across different sites, except for the indirect influences of STN and STK via STVDI (−0.18 and 0.16, respectively). Overall, this study disentangled the relative importance of plant nutrient traits and soil nutrient availability in mediating the climatic sensitivity of desert scrubs in the Tibetan Plateau. Integrating soil nutrient availability with plant functional traits together is recommended to better understand the mechanisms behind dryland dynamics under global climate change.
Self-Learning for Few-Shot Remote Sensing Image Captioning
Authors: Zhou Haonan , Du Xiaoping , Xia Lurui , Li Sen
Published: September 2022

Large-scale caption-labeled remote sensing image samples are expensive to acquire, and the training samples available in practical application scenarios are generally limited. Therefore, remote sensing image caption generation tasks will inevitably fall into the dilemma of few-shot, resulting in poor qualities of the generated text descriptions. In this study, we propose a self-learning method named SFRC for few-shot remote sensing image captioning. Without relying on additional labeled samples and external knowledge, SFRC improves the performance in few-shot scenarios by ameliorating the way and efficiency of the method of learning on limited data. We first train an encoder for semantic feature extraction using a supplemental modified BYOL self-supervised learning method on a small number of unlabeled remote sensing samples, where the unlabeled remote sensing samples are derived from caption-labeled samples. When training the model for caption generation in a small number of caption-labeled remote sensing samples, the self-ensemble yields a parameter-averaging teacher model based on the integration of intermediate morphologies of the model over a certain training time horizon. The self-distillation uses the self-ensemble-obtained teacher model to generate pseudo labels to guide the student model in the next generation to achieve better performance. Additionally, when optimizing the model by parameter back-propagation, we design a baseline incorporating self-critical self-ensemble to reduce the variance during gradient computation and weaken the effect of overfitting. In a range of experiments only using limited caption-labeled samples, the performance evaluation metric scores of SFRC exceed those of recent methods. We conduct percentage sampling few-shot experiments to test the performance of the SFRC method in few-shot remote sensing image captioning with fewer samples. We also conduct ablation experiments on key designs in SFRC. The results of the ablation experiments prove that these self-learning designs we generated for captioning in sparse remote sensing sample scenarios are indeed fruitful, and each design contributes to the performance of the SFRC method.
The Design of Cone and Pendulum Scanning Mode Using Dual-Camera with Multi-Dimensional Motion Imaging Micro-Nanosatellite
Authors: Zhi Zheng , Qu Hongsong , Tao Shuping , Zheng Liangliang , Ying Shipeng , Zhu Heqian
Published: September 2022

This paper focuses on the design of a new optical cone and pendulum scanning imaging mode for micro-nanosatellites. This kind of satellite uses a high-resolution camera with a small imaging plane to achieve high-resolution and ultra-wide coverage imaging through the three-dimensional motion of the camera’s wobble, satellite spin, and satellite orbital motion. First, this paper designs a single-camera constant speed OCPSI (optical cone and pendulum scanning imaging) mode. On the premise of ensuring coverage, the motion parameters and imaging parameters are derived. Then, in order to improve the performance and imaging quality of the system, a dual-camera variable speed OCPSI mode is designed. In this method, in order to reduce the overlap ratio, the camera is oscillated at a variable speed. Turn on the cameras in turn at the same time to minimize the overlap. This paper details these working modes. The simulation experiment is carried out using the satellite orbit of 500 km, the focal length of 360 mm, the pixel size of 2.5 μm, the resolution of [5120 × 5120], the number of imaging frames in the pendulum scanning hoop of 10, and the initial camera inclination angle of 30°. The single-camera constant speed OCPSI mode has an effective swath of 1060 km at a ground sampling distance of 5.3 m. The dual-camera variable speed OCPSI mode has an effective width of 966 km under the same conditions. Finally, the ground experiment prototype of OCPSI imaging theory is designed. We choose a camera with a pixel size of 3.45 μm, a resolution of [1440 × 1080], and a focal length of 25 mm. The ground experiment was carried out at the initial camera inclination angle of 10°, the number of imaging frames in the pendulum scanning hoop of 3, and the orbit height of 11 m. The experimental result is that the effective width of OCPSI imaging mode reaches 10.8 m. Compared with the traditional push-broom mode using the same camera, the effective width of 1.64 m is increased by seven times, and the effective width of 3.83 m is increased by three times compared to the traditional whisk-broom imaging mode. This study innovatively integrates three-dimensional motion imaging into aerospace remote sensing and provides a reference for the research on the realization of high-resolution and ultra-wide coverage of micro-nano remote sensing satellites.
Comparison of Pedestrian Detectors for LiDAR Sensor Trained on Custom Synthetic, Real and Mixed Datasets
Authors: Jabłoński Paweł , Iwaniec Joanna , Zabierowski Wojciech
Published: September 2022

Deep learning algorithms for object detection used in autonomous vehicles require a huge amount of labeled data. Data collecting and labeling is time consuming and, most importantly, in most cases useful only for a single specific sensor application. Therefore, in the course of the research which is presented in this paper, the LiDAR pedestrian detection algorithm was trained on synthetically generated data and mixed (real and synthetic) datasets. The road environment was simulated with the application of the 3D rendering Carla engine, while the data for analysis were obtained from the LiDAR sensor model. In the proposed approach, the data generated by the simulator are automatically labeled, reshaped into range images and used as training data for a deep learning algorithm. Real data from Waymo open dataset are used to validate the performance of detectors trained on synthetic, real and mixed datasets. YOLOv4 neural network architecture is used for pedestrian detection from the LiDAR data. The goal of this paper is to verify if the synthetically generated data can improve the detector’s performance. Presented results prove that the YOLOv4 model trained on a custom mixed dataset achieved an increase in precision and recall of a few percent, giving an F1-score of 0.84.