ARTICLE | doi:10.20944/preprints202106.0410.v1
Subject: Biology And Life Sciences, Anatomy And Physiology Keywords: highly pathogenic avian influenza viruses, pathogenicity factors.
Online: 15 June 2021 (14:29:26 CEST)
The H7 subtype of avian influenza viruses (AIV) stands out among other AIV. The H7 viruses cir-culate in ducks, poultry, equine and have repeatedly caused outbreaks of disease in humans. In or-der to study the pathogenicity factors of H7N1 viruses, several variants were obtained, starting with laboratory strain, with a history of 12 passages through chicken embryos. This strain, A/chicken/Rostock/R0p/1934(H7N1) (R0p) had only 3 substitution in HA relatively A/Chicken/Rostock/45/34(H7N1), substitution Arg140Gly among them. 10 variants of this strain was obtained and studied to ascertain its biological property, genome stability and factors of patho-genicity. Strain R0p had decreased virulence for chicken, comparing with described in literature virulence of A/FPV Rostock/34 and A/chicken/Rostock/34 viruses. After 10 passages through the chicken lungs variant was obtained much more pathogenic than the starting R0p. The study of in-termediate passages through the chicken lungs showed that the jump in pathogenicity had occurred sharply between the fifth and sixth passage. By cloning these variants, a pair of strains (R5p and R6p) were obtained, and the complete genomes of these strains were sequenced. Single amino acid substitution was revealed, namely reversion Gly140Arg in HA1. This amino acid is located at the head part of the hemagglutinin, adjacent to the receptor-binding site. In addition to the increased pathogenicity for chicken and mice, R6p differs from R5p in the pattern of foci in cell culture and an increased affinity for a negatively charged receptor analogue, while maintaining a pattern of recep-tor binding specificity and the pH optimum of the HA conformational change.
Subject: Biology And Life Sciences, Virology Keywords: highly pathogenic avian influenza viruses, pathogenicity factors.
Online: 10 May 2021 (14:22:23 CEST)
The H7 subtype of avian influenza viruses (AIV) stands out among other AIV. H7 viruses circulate in ducks, poultry, equine and have repeatedly caused outbreaks of disease in humans. In order to study the pathogenicity factors of H7N1 viruses, several laboratory variants of the A/FPV/Rostock/34 (H7N1) strain were obtained by passages in the chicken lungs. After 10 such passages, a variant was obtained that differed from the parent virus by amino acid substitutions Val109Phe in PB2, Gln621Lys in PB1, Thr32Ala and Leu586Phe in PA Gly140Arg in HA1 and Ala101Thr in HA2 (numbering by H3), Ser82Arg in M2, Arg118Lys and Met124Arg in NS1. No differences were found in proteins NA, NP, M1 and NS2. The resulting variant was hundreds of times more pathogenic for chickens than the original laboratory variant of the virus. The study of intermediate passages showed that the jump in pathogenicity occurs sharply between the fifth and sixth passage through the chicken lungs. By cloning these variants, a pair of strains (R5p and R6p) were obtained, and the complete genomes of these strains were sequenced. Single amino acid substitution was revealed, namely Gly140Arg in HA1. It is important to emphasize that this substitution is a reversion, since Arg is located in position 140 HA1 of original the A/FPV/Rostock/34 (H7N1) virus (GenBank). This amino acid is located at the head part of the hemagglutinin, adjacent to the receptor-binding site. In addition to the increased pathogenicity, R6p differs from R5p by an increased affinity for a negatively charged receptor analogue, an increased affinity for MDCK cells, while maintaining a receptor specificity profile.
ARTICLE | doi:10.20944/preprints202305.1027.v1
Subject: Biology And Life Sciences, Virology Keywords: Highly pathogenic avian influenza; H5N1/H9N2 reassortant virus; Nigeria
Online: 15 May 2023 (10:38:06 CEST)
In 2021, amidst the COVID-19 pandemic and global food insecurity, the Nigerian poultry sector was yet exposed to highly pathogenic avian influenza (HPAI) virus and its economic challenges. Between 2021 and 2022, HPAI caused 467 outbreaks reported in 31 of the 37 administrative regions in Nigeria. In this study, we characterized the genome of 97 influenza A viruses of the subtypes H5N1, H5N2 and H5N8 identified in different agro-ecological zones and farms during the 2021-2022 epidemic. The phylogenetic analysis of the HA genes showed widespread distribution of the H5Nx clade 188.8.131.52b and similarity with the HPAI H5Nx viruses detected in Europe since late 2020. Topology of the phylogenetic trees indicates the occurrence of several independent introductions of the virus into the country followed by a regional evolution of the virus most probably linked to its persistent circulation in West African territories. An additional evidence of the evolutionary potential of HPAI viruses circulating in this region is the identification in this study of a putative H5N1/H9N2 reassortant virus in a mixed-species commercial poultry farm. Our data confirm Nigeria as a crucial hotspot for HPAI virus introduction from the Eurasian territories and reveal a dynamic pattern of avian influenza virus evolution within the Nigerian poultry population.
COMMUNICATION | doi:10.20944/preprints202012.0677.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: highly pathogenic avian influenza virus; H5N8; falcated duck
Online: 28 December 2020 (10:32:26 CET)
We isolated two highly pathogenic avian influenza viruses (HPAIVs) of subtype H5N8 clade 184.108.40.206b from falcated duck (Anas falcata) feces and environmental water collected at an overwintering site in Japan. Our isolates were almost genetically identical to each other and showed high genetic similarity with H5N8 HPAIVs recently isolated in South Korea, a distant part of Japan, and European countries. These results suggest the potential role of falcated ducks in the dissemination of HPAIVs.
ARTICLE | doi:10.20944/preprints202310.1557.v1
Subject: Biology And Life Sciences, Animal Science, Veterinary Science And Zoology Keywords: Highly Pathogenic Avian Influenza (HPAI); Biosecurity Zones; Machine Learning; Risk Analysis; Pre-emptive depopulation
Online: 24 October 2023 (16:46:15 CEST)
Over the last decade, highly pathogenic avian influenza (HPAI) has severely affected poultry production systems across the globe. In particular, massive pre-emptive depopulation of all poultry within the certain distance has raised concerns regarding animal welfare and food security. Thus, alternative approaches to reducing unnecessary depopulation, such as risk-based depopulation, are highly demanded. This paper proposes a data-driven method to generate a rule table and risk score for each farm to identify preventive measures against HPAI. To evaluate the proposed method, 105 cases of HPAI occurring in a total of 381 farms in Jeollanam-do from 2014 to 2023 were evaluated. The accuracy of preventive measure identification was assessed for each case using both the conventional culling method and the proposed data-driven method. The evaluation showed that the proposed method achieved an accuracy of 84.19%, significantly surpassing the previous 10.37%. The result was attributed to the proposed method reducing the false-positive rate by 83.61% compared with the conventional method, thereby enhancing the reliability of identification. The proposed method is expected to be utilized in selecting farms for monitoring and management of HPAI.
ARTICLE | doi:10.20944/preprints202308.1579.v1
Subject: Biology And Life Sciences, Animal Science, Veterinary Science And Zoology Keywords: highly pathogenic avian influenza A H5N8; clade 220.127.116.11b; Kosovo; domestic poultry; phylogenetic network analysis; viruses; persistent circulation
Online: 22 August 2023 (12:59:41 CEST)
In this study, we report the first outbreak of highly pathogenic avian influenza (HPAI) A H5N8, clade 18.104.22.168b in Kosovo on May 19, 2021. The outbreak consisted of three temporal phases: May–June 2021, September–November 2021, and January–May 2022. In total, 32 backyard and 10 commercial holdings tested positive for the virus, affecting 179,198 poultry. Interestingly, the third and last phase of the outbreak coincided with the massive H5N1 clade 22.214.171.124b epidemic in Europe. Phylogenetic analyses of 28 viral strains from Kosovo revealed that they were closely related to the H5N8 clade 126.96.36.199.b viruses that have been circulating in Albania, Bulgaria, Croatia, Hungary, and Russia in early 2021. Whole genome sequencing of the 25 and partial sequencing of 3 H5N8 viruses from Kosovo showed high nucleotide identity, forming a distinctive cluster and suggesting a single introduction. The results of the network analysis were in accordance with the three epidemic waves and suggested that the viral diffusion could have been caused by secondary spreads among farms and/or different introductions of the same virus from wild birds. The persistent circulation of the same virus over a one-year period highlights the potential risk of the virus becoming endemic, especially in settings with non-adequate biosecurity.
ARTICLE | doi:10.20944/preprints202111.0184.v2
Subject: Biology And Life Sciences, Virology Keywords: baloxavir marboxil; H5N1 highly pathogenic avian influenza virus; viral replication; inhibition; lung inflammation; combination therapy; oseltamivir
Online: 12 January 2022 (13:18:58 CET)
Human infections caused by the H5 highly pathogenic avian influenza virus (HPAIV) sporadically threaten public health. The susceptibility of HPAIVs to baloxavir acid (BXA), a new class of inhibitors for the influenza virus cap-dependent endonuclease, has been confirmed in vitro, but it has not yet been fully characterized. Here, the efficacy of BXA against HPAIVs, including recent H5N8 variants, was assessed in vitro. The antiviral efficacy of baloxavir marboxil (BXM) in H5N1 virus-infected mice was also investigated. BXA exhibited similar in vitro activities against H5N1, H5N6, and H5N8 variants tested in comparison with seasonal and other zoonotic strains. Compared with oseltamivir phosphate (OSP), BXM monotherapy in mice infected with the H5N1 HPAIV clinical isolate, the A/Hong Kong/483/1997 strain, also caused a significant reduction in viral titers in the lungs, brains, and kidneys, thereby preventing acute lung inflammation and reducing mortality. Furthermore, compared with BXM or OSP monotherapy, combination treatments with BXM and OSP using a 48-hour delayed treatment model showed a more potent effect on viral replication in the organs, accompanied by improved survival. In conclusion, BXM has a potent antiviral efficacy against H5 HPAIV infections.
ARTICLE | doi:10.20944/preprints202208.0024.v1
Subject: Biology And Life Sciences, Virology Keywords: highly pathogenic avian influenza viruses; H5N8; H5N5; Clade 188.8.131.52; phylogenetic network analyses; next-generation sequencing; MinION; epidemiology
Online: 1 August 2022 (14:57:42 CEST)
During autumn/winter in 2016 – 2017 and 2020 – 2021, highly pathogenic avian influenza viruses (HPAIV) caused severe outbreaks in Germany and Europe. Multiple clade 184.108.40.206b H5 HPAI subtypes were responsible for increased mortality in wild birds and high mortality and massive losses in the poultry sector. To clarify putative entry sources and delineate interconnections between outbreaks in poultry holdings and wild birds, we applied whole-genome sequencing and phylodynamic analyses combined with the results of epidemiological outbreak investigations. Varying outbreak dynamics of the distinct reassortants allowed for the identification of individual, putatively wild bird-mediated entries into backyard holdings, several clusters comprising poultry holdings, local virus circulation for several weeks, direct farm-to-farm transmission and potential reassortment within a turkey holding with subsequent spill-over of the novel reassorted virus into the wild bird population. Whole-genome sequencing allowed for allowed for a unique high-resolution molecular epidemiology analysis of HPAIV H5Nx outbreaks, recommended to be used as a standard tool. The presented detailed account of the genetic, temporal and geographical characteristics of the recent German HPAI H5Nx situation emphasizes the role of poultry holdings as an important source of novel genetic variants and reassortants.
ARTICLE | doi:10.20944/preprints202206.0058.v1
Subject: Biology And Life Sciences, Virology Keywords: H5N8; HPAI; avian influenza; Highly Pathogenic avian influenza; outbreak; poultry
Online: 6 June 2022 (03:59:27 CEST)
In 2020-2021, the second massive dissemination of a highly-pathogenic avian influenza (HPAI) of H5Nx subtype occurred in Europe. During this period, the virus caused numerous outbreaks in poultry, including in the Czech Republic. In the present study, we provide an insight into the genetic variability of the Czech/2021 (CZE/2021) H5N8 viruses to determine the relationships between strains from wild and domestic poultry and to infer transmission routes between the affected flocks of commercial poultry. For this purpose, whole genome sequencing and phylogenetic analysis of 70 H5N8 HPAI genomes representing 79.7% of the cases were performed. All CZE/2021 H5N8 viruses belonged to the 220.127.116.11b H5 lineage and circulated without reassortment, retaining the A/chicken/Iraq/1/2020 H5N8-like genotype constellation. Phylogenetic analysis suggested frequent local transmission of H5N8 HPAI from wild birds to minor poultry and extensive farm-to-farm spread among commercial poultry farms. In addition, the analysis suggested one cross-border transmission event. Indirect transmission via contaminated materials was considered the most likely source of infection. Improved biosecurity and increased collaboration between the field veterinarians and the laboratory are essential to limit the local spread of the virus and to reveal and interrupt critical routes of infection.
ARTICLE | doi:10.20944/preprints202211.0545.v1
Subject: Biology And Life Sciences, Animal Science, Veterinary Science And Zoology Keywords: H5N1; HPAI; avian influenza; highly pathogenic avian influenza; outbreak; poultry
Online: 29 November 2022 (09:11:22 CET)
In 2021/2022, the re-emergence of highly pathogenic avian influenza (HPAI) occurred in Europe. The outbreak was seeded from two sources, resident and reintroduced viruses, which is unprecedented in the recorded history of avian influenza. The dominating subtype was H5N1, representing a reversion to the original A/goose/Guangdong/1/1996-like subtype combination. In this study, we present a whole genome sequence and a phylogenetic analysis of 57 H5N1 HPAI and two low pathogenic avian influenza (LPAI) H5N1 strains collected in the Czech Republic during 2021/2022. Phylogenetic analysis revealed close relationships between H5N1 genomes from poultry and wild birds and secondary transmission in commercial geese. The genotyping showed considerable genetic heterogeneity among Czech H5N1 viruses with six different HPAI genotypes, three of which were apparently unique. In addition, second-order reassortment relationships were observed with the direct involvement of co-circulating H5N1 LPAI strains. The genetic distance between Czech H5N1 HPAI and the closest LPAI segments available in the database illustrates the profound gaps in our knowledge of circulating LPAI strains. The changing dynamics of HPAI in the wild may increase the likelihood of future HPAI outbreaks and present new challenges in poultry management, biosecurity, and surveillance.
ARTICLE | doi:10.20944/preprints202301.0480.v1
Subject: Biology And Life Sciences, Virology Keywords: avian influenza; highly pathogenic avian influenza; next generation sequencing; whole genome sequencing; nanopore technology; methods comparison; clinical validation
Online: 26 January 2023 (15:19:53 CET)
As exemplified by the global response to the SARS-CoV-2 pandemic, whole genome sequencing played an important role in monitoring the evolution of novel viral variants and provided guidance on potential antiviral treatments. The recent rapid and extensive introduction and spread of highly pathogenic avian influenza virus in Europe, North America and elsewhere raises the need for similarly rapid sequencing to aid in appropriate response and mitigation activities. To facilitate this objective, we investigated a next generation sequencing platform that uses a portable nanopore sequencing device to generate and present data in real time. This platform offers the potential to extend in-house sequencing capacities to laboratories that may otherwise lack resources to adopt sequencing technologies requiring large benchtop instruments. We evaluated this platform for routine use in a diagnostic laboratory. In this study we evaluated different primer sets for the whole genome amplification of influenza A virus and evaluated five different library preparation approaches for sequencing on the nanopore platform using the MinION flow-cell. A limited amplification procedure and a rapid procedure were found to be best among the approaches taken.
ARTICLE | doi:10.20944/preprints202002.0391.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: Highly Pathogenic Avian Influenza Virus, Low Pathogenic Avian Influenza Virus, Evolution, Virulence Determinants, non-H5/H7, Cleavage Site, Chicken-to-Chicken Transmission, Virulence, Protease
Online: 26 February 2020 (11:13:35 CET)
Highly pathogenic (HP) avian influenza viruses (AIVs) are naturally restricted to H5 and H7 subtypes with a polybasic cleavage site (CS) in the hemagglutinin (HA) and any AIV with an intravenous pathogenicity index (IVPI) ≥1.2. Only few non-H5/H7 viruses fulfill the criteria of HPAIVs; nevertheless, it remains unknown why these viruses did not spread in domestic birds. In 2012, a unique H4N2 virus with a polybasic CS 322PEKRRTR/G329 was isolated from quails in California which, however, was avirulent in chickens. This is the only known non-H5/H7 virus with four basic amino acids in the HACS. Here, we investigated the virulence of this virus in chickens after expansion of the polybasic CS by substitution of T327R (322PEKRRRR/G329) or T327K (322PEKRRKR/G329) with or without reassortment with HPAIVs H5N1 and H7N7. The impact of single mutations or reassortment on virus fitness in vitro and in vivo was studied. Efficient cell culture replication of T327R/K carrying H4N2 viruses increased by trypsin, particularly in MDCK cells, and reassortment with HPAIV H5N1. Likewise, replication, virus excretion and bird-to-bird transmission of H4N2 was remarkably compromised by the CS mutations, but restored after reassortment with HPAIV H5N1, although not with HPAIV H7N7. Viruses carrying the H4-HA with or without R327 or K327 mutations and the other gene segments from HPAIV H5N1 exhibited high virulence and efficient transmission in chickens. Together, increasing the number of basic amino acids in the H4N2 HACS was detrimental for viral fitness particularly in vivo but compensated by reassortment with HPAIV H5N1. This may explain the absence of non-H5/H7 HPAIVs in poultry.
ARTICLE | doi:10.20944/preprints202311.1922.v1
Subject: Artificial Intelligence And Machine Learning, Computer Science And Mathematics Keywords: highly automated vehicles; robotics; modeling; obstacle avoidance
Online: 30 November 2023 (10:35:44 CET)
When implementing a control system for a ground-based unmanned vehicle (UV) used in agri-culture, an important factor is the low cost of the equipment used, so the use of cameras without lidars for navigation, avoiding obstacles, and ensuring movement safety seems promising. En-suring the safety of movement of UV consists of developing methods and means that make it possible to bypass static and dynamic obstacles and make an emergency stop if it is impossible to bypass. The article describes methods and software that provide detection of objects surrounding the UV through the use of the YOLOv8 neural network, space free for movement through the use of se-mantic segmentation with the MobileNetV3 network architecture, tools for combining several data sources to build a local perception map, as well as linear and angular speed of the UV based on calculating the optimal direction of movement for avoiding obstacles. Testing of the developed methods and software was realized in the Webots simulation environment. Software is developed with ROS2.
ARTICLE | doi:10.20944/preprints201809.0391.v1
Subject: Chemistry And Materials Science, Surfaces, Coatings And Films Keywords: cigarette filter; superhydrophobic; highly selective; absorbent; oil spillage
Online: 19 September 2018 (21:36:11 CEST)
Ecological and environmental damage caused by oil spillage has attracted great attention. Used cigarette filter (CF) has also caused negative environmental consequences. Converting CF to economical materials is a feasible way to address these problems. In this study, we demonstrate a simple method for production of a highly hydrophobic absorbent from CF. CF was modified by using different volume ratios of octadecyltrichlorosilane and methyltrimethoxysilane. When the volume ratio was 3:2, the modified CF had the high water contact angle of 155°. It could selectively and completely absorb silicone oil from an oil-water mixture and showed a good absorption capacity of 38.3 g/g. The absorbed oil was readily and rapidly recovered by simple mechanical squeezing, and it could be reused immediately without any additional treatments. The as-obtained superhydrophobic modified CF retained an absorption capacity of 80% for pump oil and 82% for silicone oil after 10 cycles. The modified CF showed good elasticity in the test of repeated use. The present study provides novel design of a functional material for development of hydrophobic absorbents from used CF via a facile method toward oil spillage cleanup as well as a new recycling method of CF to alleviate the environmental impact.
ARTICLE | doi:10.20944/preprints201807.0392.v1
Subject: Chemistry And Materials Science, Electrochemistry Keywords: electrodeposition; platinum; highly oriented pyrolytic graphite; 2D growth
Online: 20 July 2018 (16:08:11 CEST)
We discuss the electrodeposition of two-dimensional (2D) Pt-nanostructures on HOPG achieved under constant applied potential versus a Pt counter electrode (Eappl = ca. - 2.2 V vs RHE). The deposition conditions are discussed in terms of the electrochemical behavior of the electrodeposition precursor (H2PtCl6). We performed cyclic voltammetry (CV) of the electrochemical Pt deposit on HOPG and on Pt substrates to study the relevant phenomena that affect the morphology of Pt deposition. Under conditions where the Pt deposition occurs and H2 evolution is occurring at the diffusion-limited rate (- 0.3 V vs RHE), Pt forms larger structures on the surface of HOPG, and the electrodeposition of Pt is not limited by diffusion. This indicates the need for large overpotentials to direct the 2D growth of Pt. Investigation of the possible effect of Cl- showed that Cl- deposits on the surface of Pt at low overpotentials, but strips from the surface at potentials more positive than the electrodeposition potential. The CV of Pt on HOPG is a strong function of the nature of the surface. We propose that during immersion of HOPG in the electrodeposition solution (3 mM H2PtCl6, 0.5 M NaCl, pH 2.3) Pt islands are formed spontaneously, and these islands drive the growth of the 2D nanostructures.
ARTICLE | doi:10.20944/preprints201806.0237.v1
Subject: Biology And Life Sciences, Agricultural Science And Agronomy Keywords: biochar; compost; nutrient retention; highly weathered soil; Chinese cabbage
Online: 14 June 2018 (15:46:36 CEST)
Highly weathered soils in the tropics are low in fertility, negatively affecting plant growth. The potential of biochar for improving soil nutrient retention is reportedly promising, triggering this study to assess the nutrient retention capacities of two biochars when applied at 2% in combination with two composts also applied at 2% to an Ultisol (Ustic Kanhaplohumult, Leilehua series) and an Oxisol (Rhodic haplustox, Wahiawa series) of Hawai’i. Chinese cabbage (Brassica rapa cv. Bonsai) was used as the test plant in two greenhouse plantings, which had a factorial completely randomized design with three replicates per treatment. The results indicated that the combined additions of biochar and compost significantly increased the pH, EC, P and K of the soils; improved Ca, Mg and Fe uptake; and increased shoot and total cabbage fresh and dry matter. Exchangeable aluminum in the Ultisol was decreased from 2.5 cmol+/kg to virtually zero. Extractable Mn and Fe in the high Mn-Oxisol were decreased by 55 and 42%, respectively. Chinese cabbage growth in the Ultisol amended with the lac tree (Schleichera oleosa) wood biochar and vermicompost was almost twice over lime at 2 cmol+/kg. Essential nutrients in the plant tissues, with the exception of N and K, were sufficient for the cabbage growth, suggesting increases in nutrients and reduced soil acidity by the additions of biochar combined with compost were the probable cause.
REVIEW | doi:10.20944/preprints201809.0149.v1
Subject: Social Sciences, Psychology Keywords: sensory processing sensitivity; highly sensitive person; highly sensitive child; differential susceptibility; environmental sensitivity; temperament; personality; aetiology; animal model; neuroscience; cognition; mental health
Online: 10 September 2018 (04:58:01 CEST)
Sensory Processing Sensitivity (SPS) is a trait describing inter-individual differences in sensitivity to environments, both positive and negative ones. SPS has attracted growing societal interest. However, (neuro)scientific evidence is lagging behind. We critically discuss how to measure SPS, how it relates to other theories of Environmental Sensitivity and other temperament and personality traits, how SPS interacts with environments to influence (a)typical development, what the underlying aetiologies and mechanisms are, and its relation to mental disorders involving sensory sensitivities. Drawing on the diverse expertise of the authors, we set an agenda for future research to stimulate the field. We conclude that SPS is a heritable, evolutionarily conserved trait, linked to increased risk for psychopathology and stress-related problems in response to negative environments, as well as to greater benefits (e.g., intervention responsivity, positive mood) in positive environments. We need advances in objective assessment of SPS, understanding mechanisms, differentiating it from (seemingly) related mental disorders, to exploit the potential of SPS to improve mental health, preserve human capital, and prevent adverse effects.
ARTICLE | doi:10.20944/preprints202308.0365.v1
Subject: Medicine And Pharmacology, Veterinary Medicine Keywords: cerebral artery; duck; endothelium; highly pathogenic avian influenza; nitric oxide
Online: 3 August 2023 (14:50:39 CEST)
The basilar arterial endothelium mediates blood-vessel relaxation, partly through release of nitric oxide (NO). Apoptosis of cerebrovascular endothelial cells is linked to high mortality rate in chickens infected with highly pathogenic avian influenza virus, but interestingly ducks exhibit greater resistance to this virus. In this study, we examined the responsiveness of duck basilar arteries (BAs) to various vasoactive substances, including 5-hydroxytryptamine (5-HT), histamine (His), angiotensin (Ang) II, noradrenaline (NA), acetylcholine (ACh), and avian bradykinin ornithokinin (OK), aiming to characterize the receptor subtypes involved and the role of endothelial NO in vitro. Our findings suggest that arterial contraction is mediated by 5-HT1 and H1 receptors, while relaxation is induced by β3-adrenergic and M3 receptors. Additionally, OK elicited a biphasic response in duck BAs, and Ang II had no effect. Endothelial NO appears to be crucial in relaxation mediated by M3 and OK receptors, but not β3-adrenergic receptors, in the duck BA. The reduced endothelial NO involvement in the receptor-mediated relaxation response in duck BAs represents a clear difference from the corresponding response reported in chicken BAs. This physiological difference may explain differences in lethality between ducks and chickens when vascular endothelial cells are infected by the virus.
ARTICLE | doi:10.20944/preprints202309.0089.v1
Subject: Environmental And Earth Sciences, Geochemistry And Petrology Keywords: Ion-adsorption HREE deposits; Zircon; Magmatic-hydrothermal evolution; Highly fractionated granite
Online: 1 September 2023 (16:34:36 CEST)
The Shitouping pluton in Jiangxi Province, southern China, hosts an ion-adsorption heave rare earth element (HREE) deposit identified by recently geological survey. This study reveals the HREE pre-enrichment mechanism during the magma-hydrothermal process of granitic bedrock based on the comprehensive study of zircon structure and composition. Zircon from the Shitouping pluton, composed of syenogranite and monzogranite, can be categorized into three types based on structure and compositions. The Type-1 zircons, the predominate type in monzogranite granite, are early magmatic zircons with prismatic crystals and bright oscillatory zoning. In contrast, the late magmatic-hydrothermal zircons (Type-2 and Type-3) are mainly occurred in the syenogranite. The Type-2 zircons occur as murky euhedral crystals crystallized in the late magmatic stage. The Type-3 zircons with irregular zoning and abundant mineral inclu-sions in BSE images are closely associated with Type-2 zircons, possibly formed via intense hy-drothermal alteration during the hydrothermal stage. The increase in Y/Ho ratios from Type-1 to Type-3 zircon indicates that the Shitouping syenogranites underwent magmatic to hydrothermal evolution. Compared with Type-1 and Type-2 zircons, Type-3 zircons exhibit the highest con-centrations of F and HREEs. The significant increase of HREE concentrations both in zircons and bulk-rock composition of syenogranite can be attributed to the introduction of HREE-rich fluids during magma evolution. Under this condition, the HREEs mainly hosted in fluorocarbonates, which can easily release HREE3+ to generate ion-adsorption deposits during the weathering process. Therefore, we propose that increase of HREE contents in zircon reflect the exsolution of HREE-rich fluids during the magma evolution, which is important factor controlling HREE en-richment in Shitouping syenogranites and further generation of ion-adsorption HREE deposits.
ARTICLE | doi:10.20944/preprints201706.0062.v1
Subject: Social Sciences, Library And Information Sciences Keywords: h-index; citations; published version; Scopus database; highly cited paper; bibliometrics
Online: 14 June 2017 (06:07:12 CEST)
The number of citations that a paper has received is the most commonly used indicator to measure the quality of research. Researchers, journals, and universities want to receive more citations for their scholarly publications to increase their h-index, impact factor, and ranking respectively. In this paper, we tried to analyses the effect of the number of available Google Scholar versions of a paper on citations count. We analyzed 10,162 papers which are published in Scopus database in year 2010 by Malaysian top five universities. Then we developed a software to collect the number of citations and versions of each paper from Google Scholar automatically. The result of spearman correlation coefficient revealed that there is positive significant association between the number of Google Scholar versions of a paper and the number of times a paper has been cited.
ARTICLE | doi:10.20944/preprints201703.0139.v1
Subject: Biology And Life Sciences, Plant Sciences Keywords: Fritillaria ussuriensis, Fritillaria cirrhosa, Chloroplast genome, Comparative analysis, Highly divergent region
Online: 17 March 2017 (16:30:34 CET)
The genus Fritillaria belongs to the widely distributed family Liliaceae. The bulbs of Fritillaria ussuriensis and Fritillaria cirrhosa are valuable herbaceous medicinal ingredients. However, they are still used indiscriminately in herbal medicine. Identification and molecular phylogenic analysis of Fritillaria species is therefore required. Here, we report the complete chloroplast (cp) genome sequences of F. ussuriensis and F. cirrhosa. The two Fritillaria cp genomes were 151,524 and 151,083 bp in length, respectively, including a pair of inverted repeat regions (52,678 and 52,156 bp) separated by a large single copy region (81,732 and 81,390 bp) and small single copy region (17,114 and 17,537 bp). A total of 111 genes in F. ussuriensis and 112 in F. cirrhosa comprised 77 protein-coding genes in F. ussuriensis and 78 in F. cirrhosa, 30 tRNA genes, and four rRNA genes. The gene order, content, and orientation of the two Fritillaria cp genomes exhibited the general structure of flowering plants, and were similar to those of other Fritillaria species. Comparison of the six Fritillaria species’ cp genomes indicated seven highly divergent regions in intergenic spacers and in the matK, rpoC1, rpoC2, ycf1, ycf2, ndhD, and ndhF coding regions. We established the position of the six species through phylogenic analysis. The complete chloroplast genome sequences of two Fritillaria species will be useful genomics resources for identification of Fritillaria species and for studying the phylogenetic relationship among Fritillaria species within the Liliaceae family.
REVIEW | doi:10.20944/preprints202310.1676.v1
Subject: Social Sciences, Education Keywords: publication trends; coronavirus; top papers; highly cited paper; PEO; PLO and CLO
Online: 26 October 2023 (10:57:09 CEST)
In the educational process, quality has long been considered a critical component. It may get impacted due to different factors especially when talking about the COVID19 pandemic. The purpose of this investigation is to explore the impact and relationship between COVID-19 and the quality of education using bibliometric analysis. As face-to-face learning shifts to online learning, this research investigates how the COVID-19 epidemic has affected education quality, concentrating on Programme Educational Outcomes (PEOs), Programme Learning Outcomes (PLOs), and Course Learning Outcomes (CLOs). The research covers pandemic online education, literature, and trends. There are two important steps in any bibliometric analysis selecting keywords and databases. The initial set of keywords was selected by the authors' experience and then an online survey study through Google Forms was conducted among experts in the research area. This was followed by a search of the selected keywords in the databases consisting of PubMed, Web of Science (WoS), and SCOPUS. Therefore, the final data was collected from the SCOPUS database on August 24, 2021. Hence, 182 documents were considered for the current study. The document's data were analysed by using the “visualization of similarities” (VOS) Viewer software and the R-Tool of the Bibliometrix-package that was specifically designed for quantitative Bibliometrics research. Based on the obtained data, the results showed the quality of education that may get impacted by the changing of the education delivery from face-to-face to online-based learning. In conclusion, this study showed the importance of studying the correlation and impact of COVID-19 on the quality of education.
ARTICLE | doi:10.20944/preprints202305.0651.v1
Subject: Chemistry And Materials Science, Organic Chemistry Keywords: Leucas zeylanica; Highly oxygenated; Diterpenoids; Anti-inflammatory activity; Molecular docking; Zebrafish model
Online: 9 May 2023 (12:09:17 CEST)
Four previously undescribed highly oxygenated diterpenoids (1–4), zeylleucapenoids A–D, characterized by halimane and labdane skeletons, were isolated from the aerial parts of Leucas zeylanica. Their structures were elucidated primarily by NMR experiments. The absolute configuration of 1 was established by theoretical ECD calculations and X-ray crystallographic analysis, whereas those for 2−4 were assigned by theoretical ORD calculations. Zeylleucapenoid D (4), with an IC50 value of 38.45 μM in RAW264.7 macrophages and nontoxic activity for zebrafish embryo, and obviously inhibited pro-inflammatory cytokines TNF-α and IL-6 in a dose-dependent manner. Compound 4 inhibited of the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). Furthermore, molecular docking analysis indicated the possible mechanism of action for 4 may be bind to targets by hydrogen- and hydrophobic- bond interactions.
ARTICLE | doi:10.20944/preprints202209.0013.v1
Subject: Medicine And Pharmacology, Neuroscience And Neurology Keywords: pediatric onset multiple sclerosis; POMS; highly effective treatments; disease modifying drugs; DMD
Online: 1 September 2022 (08:48:04 CEST)
Introduction: Pediatric-Onset Multiple Sclerosis (POMS) is characterized by high inflammatory disease activ-ity. Our aim was to describe the treatment sequencing and report the impact Highly Effective Disease Modifying Treatment (HET) had on disease activity. Materials and Methods: 2/5 consecutive POMS were administered HET as initial therapy after diagnosis. Data on treatment sequencing, relapses and MRIs were collected during the follow-up. Results: Our patients had an average age of 13.8 years (range 9-17) at di-agnosis and 13.4 years (range 9-16) at disease onset, 2/5 (40%) POMS were female. The pre-treatment aver-age annualized relapse rate was 1.6 (range 0.8-2.8) and the average follow-up length was 5 years (range 3-7). A total of 2/5 (40%) patients were stable on HET at initial therapy, 3/5 (60%) required an escalation to more aggressive treatment, even if two of them had been put on HET as initial treatment. Four out of five patients (80%) had No Evidence of Disease Activity-3 status (NEDA-3) at an average follow-up of 3 years (range 2-5). Conclusion: it has been observed that in a recent time period all the cases had prompt diagnosis, early HET or escalation to HET with a good outcome in 80% of the cases.
ARTICLE | doi:10.20944/preprints201902.0130.v1
Subject: Engineering, Control And Systems Engineering Keywords: Ad Hoc Networks; Highly Dynamic; Mobility; Opportunistic Routing; Performance Improvement; Transmission Inefficiency
Online: 14 February 2019 (10:29:01 CET)
Opportunistic Routing is a promising paradigm that has been proposed for efficient and reliable transfer of data packets in mobile ad hoc networks. This routing strategy takes advantage of the broadcasting nature of the wireless medium to increase the number of probable forwarding devices and improves the reliability of data transfer in the network. Opportunistic Routing utilizes the reception of the same broadcasted packet at multiple devices in the network and selects one best forwarder dynamically from the set of multiple receivers. A number of opportunistic routing protocols have been proposed over these years for effective data delivery in ad hoc networks. But as the speed and mobility of devices increases in the network, performances of the existing opportunistic routing protocols degrade considerably, leading to reduced Quality of Service and poor transmission efficiency. The exceptional potential of opportunistic routing is thus underutilized. In this research we introduce Optimized Opportunistic Routing (OOR) strategy that guarantee excellent Quality of Service and high transmission efficiency to the latest applications using opportunistic routing for communication in highly dynamic ad hoc networks. Simulation results show that our method achieve significant performance improvements compared to all other existing opportunistic routing protocols in highly dynamic mobile ad hoc networks.
COMMUNICATION | doi:10.20944/preprints201706.0111.v1
Subject: Social Sciences, Library And Information Sciences Keywords: improve citations; research tools; research visibility; research impact; documents publishing; highly cited
Online: 26 June 2017 (04:20:47 CEST)
Researchers, journals, and universities want to receive more citations for their scholarly publications. However, a paper citations depend on its quality, visibility and author’s online profile. Research support documents (unpublished papers, white papers, project reports, datasets, software, posters, online resources and teaching materials) can be additional source for increasing the author’s visibility. To enhance research visibility and impact, the full range of scholarly output should be available online on the open access platform. With open access platform, key research findings are made accessible immediately to the scientific community. Therefore, the publicly available research support documents may result in receiving more citations in addition to the published papers. In this paper we conducted a simplified three stages study on the benefits of research support documents publications on open access platform. We also elaborated on approaches of improving your research visibility and impact through these document.
REVIEW | doi:10.20944/preprints202309.2083.v1
Subject: Medicine And Pharmacology, Gastroenterology And Hepatology Keywords: Cystic Fibrosis; transition of care; pediatrics; Gastrointestinal care; Pancreatic enzyme; highly effective modulators
Online: 29 September 2023 (10:43:47 CEST)
Cystic Fibrosis is a chronic disease affecting multiple systems including the GI tract. Clinical manifestation in patients can start as early as infancy and vary across different age groups. With the advent of new highly effective modulators, the life expectancy of PwCF has improved significantly. Various GI aspects of CF care such as nutrition are linked to the overall improvement in morbidity, lung function, and quality of life of PwCF. The variable clinical presentations and management of GI diseases in pediatrics and adults CF should be recognized. Therefore, it is necessary to ensure efficient transfer of information between pediatric and adult providers for proper continuity of management and coordination of care at the time of transition. The transition of care is a challenging process for both patients and providers and currently, there are no specific tools for GI providers to help ensure smooth transition. In this review, we aim to highlight the crucial features of GI care at the time of transition and provide a checklist that can assist in ensuring an effective transition and ease the challenges associated with it.
ARTICLE | doi:10.20944/preprints202307.1101.v2
Subject: Physical Sciences, Condensed Matter Physics Keywords: hydrogen-rich superconductors; highly-compressed superconductors; electron-phonon coupling constant; Debye temperature; nonadiabaticity
Online: 20 July 2023 (09:32:18 CEST)
Superconductivity in highly-pressurized hydrides became primary direction for the exploration of fundamental upper limit for the superconducting transition temperature, Tc, after Drozdov et al (Nature 2015, 525, 73) discovered superconducting state with Tc=203 K in highly-compressed sulphur hydride. To date several dozens of high-temperature superconducting polyhydrides have been discovered. In addition, recently, it was reported that highly-compressed titanium and scandium exhibit record-high (up to 36 K), which is by manifold exceeded of niobium, which is the record high- ambient pressure metallic superconductor. Here we analysed experimental data on for recently discovered high-pressure superconductors (which exhibit high transition temperatures within their classes): elemental titanium (Zhang et al, Nature Communications 2022; Liu et al, Phys. Rev. B 2022), TaH3 (He et al, Chinese Phys. Lett. 2023), LaBeH8 (Song et al, Phys. Rev. Lett. 2023), and black (Li et al, Proc. Natl. Acad. Sci. 2018) and violet (Wu et al, arXiv 2023) phosphorous, to reveal the nonadiabaticity strength constant, TθTF (where Tθ is the Debye temperature, and TF the Fermi temperature) in these superconductors. The analysis showed that δ-phase of titanium and black phosphorous exhibit the Tθ/TF which are nearly identical to ones associated in A15 superconductors, while studied hydrides and violet phosphorous exhibit the constants in the same ballpark with H3S and LaH10.
ARTICLE | doi:10.20944/preprints202309.1247.v1
Subject: Engineering, Bioengineering Keywords: diffuse optical imaging; functional-ROIs; structural-ROIs; sensory-motor activity; highly sensitive cerebral activations
Online: 20 September 2023 (07:51:54 CEST)
Diffuse optical tomography (DOT) technology enables a differentiation between oxyhemoglobin (HbO) and deoxyhemoglobin (HbR) in the sensory and motor cerebral gyri, resulting in greater sensitivity for cerebral activation compared to functional magnetic resonance imaging (fMRI). Here, we introduce a novel approach where functional regions of interest (ROIs) are created based on the specific signal behavior observed in DOT measurements, in contrast to the conventional use of structural-ROIs obtained from anatomical information. The generation of cerebral activation maps involves using the general linear model (GLM) to compare the outcomes obtained from both the functional and structural ROI approaches. DOT-derived maps are then compared with maps derived from fMRI datasets considered the gold standard for assessing functional brain activity. The results obtained demonstrate the effectiveness of employing functional ROIs to improve the spatial location of functional activations in the sensory and motor cerebral gyri by leveraging the neural synchronization data provided by DOT. Furthermore, this methodology simplifies data processing in animal models, where anatomical differences compared to the human head can pose challenges. By incorporating functional ROIs prior to GLM application, this study offers enhancements to DOT analysis techniques and broadens its applicability in both human and animal models.
ARTICLE | doi:10.20944/preprints202208.0410.v1
Subject: Engineering, Civil Engineering Keywords: highly-regulated river basins; climate change; water demands; public water supply; SWAT-MODFLOW; WEAP; UKCP18
Online: 24 August 2022 (05:08:40 CEST)
In this article, we present the use of the coupled land surface model and groundwater flow model SWAT-MODFLOW with the decision support tool WEAP (Water Evaluation and Planning software) to predict future surface water abstraction scenarios in a complex river basin, under conditions of climate change. The modeling framework is applied to the Dee River catchment in Wales, United Kingdom. Regarding hydrology, the coupled model improves overall water balance and low streamflow conditions, compared to a stand-alone SWAT model. The calibrated SWAT-MODFLOW is employed with high resolution climate model data from the UKCP18 project with future scenario of RCP85 from 2020 to 2040. Then, water supply results from SWAT-MODFLOW are fed into WEAP as input for the river reach in the downstream region of the river basin. This system is utilized to create various future scenarios of surface water abstraction of public water supply in the downstream region: maximum licensed withdraw, 50 % authorized abstractions, monthly time series with 1% increase of water use, and maximum water withdraw year based on historical records repeated every year with 1% increase of water use, to estimate the unmet demands and streamflow requirement. This modeling approach can be used in other river basins to manage scenarios of supply and demand.
REVIEW | doi:10.20944/preprints202210.0206.v1
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: fatty acid desaturases; highly unsaturated fatty acids; unusual unsaturated fatty acids; sciadonic acid; sapienic acid; mead acid
Online: 14 October 2022 (09:37:18 CEST)
The human chromosome 11q13 (HSA 11q13) genomic locus is a major cancer hotspot and has been established as the most frequently altered by amplification in a variety of human cancers. The fatty acid desaturase genes (FADS1, FADS2 and FADS3) localize to the 11q12- 13.1 region. FADS2 activity is promiscuous, catalyzing biosynthesis of polyunsaturated and monounsaturated fatty acids, including unsaturated branched chain fatty acids (BCFA) by Δ6, Δ8, and Δ4 desaturation toward at least 16 substrates. Our main aim here is to review known and putative consequences of FADS2 dysregulation due to effects on the 11q13 locus in various cancer types. We searched PubMed and Google Scholar databases for articles that showed 11q13 amplification and studies reporting FADS2 function in various cancer types. FADS2 silencing causes synthesis of sciadonic acid (ScA, 5Z,11Z,14Z-20:3) in MCF7 cells and breast cancer in vivo. 5Z,11Z,14Z-20:3 is structurally identical to the eicosanoid precursor arachidonic acid (5Z,8Z,11Z,14Z–20:4) except it lacks the internal Δ8 double bond required for prostaglandin and leukotriene synthesis, among other eicosanoids. Melanoma, prostate, liver and lung cancer cells insensitive to SCD inhibition show increased FADS2 activity leading to sapienic acid (16:1n10) biosynthesis from 16:0. Elevated serum mead acid (20:3n-9) levels were found in more than a third of hepatocellular carcinoma patients, indicative of an unsatisfied demand for arachidonic acid, likely as a substrate for eicosanoids. A highly expressed circular RNA (hsa_circ_022382) within an exonic region of FADS2 is associated with shorter overall survival in colorectal cancer patients. Similarly, in lung cancer tissues circFADS2 RNA is highly expressed. Palmitic acid (16:0) is a common substrate for SCD and FADS2. FADS2 circular RNAs are at high levels in colorectal and lung cancer tissues. The evidence thusfar supports an effort for future research on the role of FADS2 as a tumor suppressor in a range of neoplastic disorders.
ARTICLE | doi:10.20944/preprints202105.0213.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: PMMA: Polymethylmethacrylate; HRGO: Highly Reduced Graphene Oxide; DSC: Differential Scanning Calorimetry; FESEM: Field Emission Scanning Electron Microscopy.
Online: 10 May 2021 (15:27:44 CEST)
Bone cement, mainly based in PMMA, is commonly used in different arthroplasty surgical proce-dures, and its use is essential for prosthesis fixation. However, its manufacturing process reaches high temperatures that can produce necrosis in the patients' surrounding tissues. In order to con-tribute to avoid this problem, the addition of graphene could delay the polymerisation of the MMA and, simultaneously, contribute to the optimisation of the composite material's properties. This article analysed the effect of the addition of different percentages of Highly Reduced Graphene Oxide (HRGO) with different wt. % (0,10, 0,50 and 1,00) and surface densities (150, 300, 500 and 750 m2/g) on the physical, mechanical, and thermal properties of commercial PMMA-based bone cement and its processing. It was noticed that a lower sintering temperature would be reached with this addition, making it less harmful to use in surgery and as it reduces its adverse effects. In contrast, the materials' density does not show significant changes, which indicates that the addi-tion of HRGO does not significantly increase its porosity. Lastly, the mechanical properties are re-duced by almost 20 %. Nevertheless, these properties are high enough so that these new materials can still fulfil their structural function.
ARTICLE | doi:10.20944/preprints201701.0030.v2
Subject: Engineering, Civil Engineering Keywords: Energy Performance of Buildings Directive (EPBD 2010); nearly zero energy standard; non-residential buildings; highly technically installed buildings; energy balance
Online: 9 January 2017 (10:35:18 CET)
The Energy Performance of Buildings Directive 2010 calls for the Nearly Zero Energy Standard for new buildings from 2021 onwards: Buildings using “almost no energy” are powered by renewable sources or energy produced by the building itself. For residential buildings, this ambitious new standard has already been reached. But for other building types this goal is still far away. The potential of these buildings to meet a Nearly Zero Energy Standard was investigated by analyzing ten case studies representing non-residential buildings with different uses. The analysis shows that the primary characteristics common to critical building types are a dense building context with a very high degree of technical installation (such as hospital, research and laboratory buildings). The large primary energy demand of these types of buildings cannot be compensated by building and property-related energy generation including off-site renewables. If the future Nearly Zero Energy Standard were to be defined with lower requirements because of this, the state related properties of Bavaria suggest that the real potential energy savings available in at least 85% of all new buildings would be insufficiently exploited. Therefore, it would be useful to instead individualize the legal energy verification process for new buildings to distinguish critical building types such as laboratories and hospitals.
REVIEW | doi:10.20944/preprints201609.0050.v1
Subject: Engineering, Chemical Engineering Keywords: DCMS, DCMSP, and sputtering; highly ionized pulse plasma magnetron sputtering (HIPIMS); bacterial inactivation kinetics; Cu and TiO2 synergic effects; interfacial charge transfer
Online: 16 September 2016 (13:31:00 CEST)
This review focuses on Cu/TiO2 sequentially and Cu-TiO2 co-sputtered catalytic/photocatalytic surfaces leading to bacterial inactivation discussing their stability, synthesis, adhesion and antibacterial kinetics. The intervention of TiO2, Cu and the synergic effect of Cu and TiO2 on films prepared by a colloidal approach and other techniques is also reviewed leading to bacterial inactivation. Processes in aerobic media and anaerobic media leading to bacterial loss of viability on multidrug resistant (MDR) pathogens, Gram-negative (-) and Gram-positive(+) bacteria are described. Insight is provided for the interfacial charge transfer mechanism under solar irradiation occurring between TiO2 and Cu. surface properties of 2D TiO2/Cu and TiO2-Cu films are correlated with the bacterial inactivation kinetics observed in the dark and under light. The intervention of these antibacterial sputtered surfaces in health-care facilities leading to MRSA-isolates is described in the dark and under the actinic light. The synergic intervention of the Cu and TiO2 films leading to bacterial inactivation prepared by direct current magnetron sputtering (DCMS), pulsed direct current magnetron sputtering (DCMSP) and highly ionized pulse plasma magnetron sputtering (HIPIMS) is reported in a detailed way.
ARTICLE | doi:10.20944/preprints201802.0163.v1
Subject: Physical Sciences, Optics And Photonics Keywords: optical metamaterials; fundamental concepts in photonics; light-matter interactions at the subwavelength and nanoscale; fundamental understanding of linear and nonlinear optical processes in novel metamaterials underpinning photonic devices and components; advancing the frontier of nanophotonics with the associated nanoscience and nanotechnology; nanostructures that can serve as building blocks for nano-optical systems; use of nanotechnology in photonics; nonlinear nanophotonics, plasmonics and excitonics; subwavelength components and negative index materials; slowing, store, and processing light pulses; materials with such capabilities that could be used for optical sensing, tunable optical delay lines, optical buffers, high extinction optical switches, novel image processing hardware, and highly-efficient wavelength converters
Online: 26 February 2018 (11:24:39 CET)
Backward electromagnetic waves are extraordinary waves with contra-directed phase velocity and energy flux. Unusual properties of the coherent nonlinear optical coupling of the phase-matched ordinary and backward electromagnetic waves with contra-directed energy fluxes are described which enable greatly-enhanced frequency and propagation direction conversion, parametrical amplification, as well as control of shape of the light pulses. Extraordinary transient processes that emerge in such metamaterials in pulsed regimes are described. The results of the numerical simulation of particular plasmonic metamaterials with hyperbolic dispersion are presented, which prove the possibility to match phases of such coupled guided ordinary and backward electromagnetic waves. Particular properties of the outlined processes in the proposed metamaterial are demonstrated through numerical simulations. Potential applications include ultra-miniature amplifiers, frequency changing reflectors, modulators, pulse shapers, and remotely actuated sensors.