Recent outbreaks of emerging and re‐emerging viruses have shown that timely detection of novel arboviruses with epidemic potential is essential to mitigate human health risks. There are rising ...concerns that emergent JEV genotype V (GV) is circulating in Asia, against which current vaccines may not be efficacious. To ascertain if JEV GV and other arboviruses are circulating in East Asia, we conducted next‐generation sequencing on 260 pools of Culex tritaeniorhynchus and Culex bitaeniorhynchus mosquitoes (6540 specimens) collected at Camp Humphreys, Republic of Korea (ROK) in 2018. Interrogation of our data revealed a highly abundant and diverse virosphere that contained sequences from 122 distinct virus species. Our statistical and hierarchical analysis uncovered correlates of potential health, virological, and ecological relevance. Furthermore, we obtained evidence that JEV GV was circulating in Pyeongtaek and, retrospectively, in Seoul in 2016 and placed these findings within the context of human and fowl reservoir activity. Sequence‐based analysis of JEV GV showed a divergent genotype that is the most distant from the GIII‐derived live attenuated SA14‐14‐2 vaccine strain and indicated regions probably responsible for reduced antibody affinity. These results emphasize recent concerns of shifting JEV genotype in East Asia and highlight the critical need for a vaccine proven efficacious against this re‐emergent virus. Together, our one‐health approach to Culex viral metagenomics uncovered novel insights into virus ecology and human health.
ABSTRACT
A Rickettsia sp. was isolated from the blood of a patient with an acute febrile illness using the shell vial technique; the isolate was named CN45Kr and was identified by molecular assay as ...Rickettsia monacensis, which was first recognized as a pathogen in Spain. Sequencing analysis showed that the gltA sequence of the isolate was identical to that of Rickettsia sp. IRS3. The ompA‐5mp fragment sequence showed 100% identity to those of R. monacensis and Rickettsia sp. In56 and ompA‐3pA In56 and 100% identity to that of Rickettsia sp. IRS3. The ompB sequence was found to have 99.9% similarity to that of R. monacensis IrR/Munich. This study confirms the pathogenicity of this agent and provides additional information about its geographic distribution.
In this paper, we propose an adaptive quantization method that can easily transfer the weights, which are trained in software network with floating point operation, to the real synaptic devices in ...hardware-based neural networks and maintain high performance. An n-type gated Schottky diode is investigated as a synaptic device, and the conductance behavior of this device is modeled successfully. Max value normalization and <inline-formula> <tex-math notation="LaTeX">3\sigma </tex-math></inline-formula> normalization are applied to the weights trained with an accuracy of 98.29% on fully connected neural network (<inline-formula> <tex-math notation="LaTeX">784\times 256\times10 </tex-math></inline-formula>) using software network. Then, the weights are quantized using the adaptive quantization method and can be transferred by adjusting the number of identical pulses applied to the synaptic devices. After applying the adaptive quantization method, accuracy rates of 98.09% and 97.20% in MNIST classification are obtained for both max value normalization and <inline-formula> <tex-math notation="LaTeX">3\sigma </tex-math></inline-formula> normalization, respectively. The proposed quantization method works well even when there is nonideality of synaptic devices such as nonlinearity of conductance behavior, limited conductance levels, and variation of conductance.
A number of studies have been conducted on the relationship between the distribution of mosquito abundance and meteorological variables. However, few studies have specifically provided specific ...ranges of temperatures for estimating the maximum abundance of mosquitoes as an empirical basis for climatic dynamics for estimating mosquito-borne infectious disease risks.
Adult mosquitoes were collected for three consecutive nights/week using Mosquito Magnet® Independence® model traps during 2018 and 2019 at US Army Garrison (USAG) Humphreys, Pyeongtaek, Gyeonggi Province, Republic of Korea (ROK). An estimate of daily mean temperatures (provided by the Korea Meteorological Administration) were distributed at the maximum abundance for selected species of mosquitoes using daily mosquito collection data after controlling for mosquito ecological cycles and environmental factors.
Using the Monte-Carlo simulation, the overall mosquito population abundance peaked at 22.7°C (2.5th-97.5th: 21.7°C-23.8°C). Aedes albopictus, vector of Zika, chikungunya, dengue fever and other viruses, abundance peaked at 24.6°C (2.5th-97.5th, 22.3°C-25.6°C), while Japanese encephalitis virus (JEV) vectors, e.g., Culex tritaeniorhynchus and Culex pipiens, peaked at 24.3°C (2.5th-97.5th: 21.9°C-26.3°C) and 22.6°C (2.5th-97.5th: 21.9°C-25.2°C), respectively. Members of the Anopheles Hyrcanus Group, some of which are vivax malaria vectors in the ROK, abundance peaked at 22.4°C (2.5th-97.5th: 21.5°C-23.8°C).
The empirical mean temperature ranges for maximum abundance were determined for each mosquito species collected at USAG Humphreys. These data contributed to the identification of relative mosquito abundance patterns for estimating mosquito-borne disease risks and developing and implementing disease prevention practices.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Paramyxoviruses, negative-sense single-stranded RNA viruses, pose a critical threat to human public health. Currently, 78 species, 17 genera, and 4 subfamilies of paramyxoviruses are harbored by ...multiple natural reservoirs, including rodents, bats, birds, reptiles, and fish. Henipaviruses are critical zoonotic pathogens that cause severe acute respiratory distress and neurological diseases in humans. Using reverse transcription-polymerase chain reaction, 115
species individuals were examined for the prevalence of paramyxovirus infections. Paramyxovirus RNA was observed in 26 (22.6%) shrews collected at five trapping sites, Republic of Korea. Herein, we report two genetically distinct novel paramyxoviruses (genus:
): Gamak virus (GAKV) and Daeryong virus (DARV) isolated from
and
, respectively. Two GAKVs and one DARV were nearly completely sequenced using next-generation sequencing. GAKV and DARV contain six genes (3'-N-P-M-F-G-L-5') with genome sizes of 18,460 nucleotides and 19,471 nucleotides, respectively. The phylogenetic inference demonstrated that GAKV and DARV form independent genetic lineages of
in
species. GAKV-infected human lung epithelial cells elicited the induction of type I/III interferons, interferon-stimulated genes, and proinflammatory cytokines. In conclusion, this study contributes further understandings of the molecular prevalence, genetic characteristics and diversity, and zoonotic potential of novel paramyxoviruses in shrews.
Background Whole-genome sequencing plays a critical role in the genomic epidemiology intended to improve understanding the spread of emerging viruses. Dabie bandavirus, causing severe fever with ...thrombocytopenia syndrome (SFTS), is a zoonotic tick-borne virus that poses a significant public health threat. We aimed to evaluate a novel amplicon-based nanopore sequencing tool to obtain whole-genome sequences of Dabie bandavirus, also known as SFTS virus (SFTSV), and investigate the molecular prevalence in wild ticks, Republic of Korea (ROK). Principal findings A total of 6,593 ticks were collected from Gyeonggi and Gangwon Provinces, ROK in 2019 and 2020. Quantitative polymerase chain reaction revealed the presence of SFSTV RNA in three Haemaphysalis longicornis ticks. Two SFTSV strains were isolated from H. longicornis captured from Pocheon and Cheorwon. Multiplex polymerase chain reaction-based nanopore sequencing provided nearly full-length tripartite genome sequences of SFTSV within one hour running. Phylogenetic and reassortment analyses were performed to infer evolutionary relationships among SFTSVs. Phylogenetic analysis grouped SFTSV Hl19-31-4 and Hl19-31-13 from Pocheon with sub-genotype B-1 in all segments. SFTSV Hl20-8 was found to be a genomic organization compatible with B-1 (for L segment) and B-2 (for M and S segments) sub-genotypes, indicating a natural reassortment between sub-genotypes. Conclusion/Significance Amplicon-based next-generation sequencing is a robust tool for whole-genome sequencing of SFTSV using the nanopore platform. The molecular prevalence and geographical distribution of SFTSV enhanced the phylogeographic map at high resolution for sophisticated prevention of emerging SFTS in endemic areas. Our findings provide important insights into the rapid whole-genome sequencing and genetic diversity for the genome-based diagnosis of SFTSV in the endemic outbreak.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
In this paper, we propose a learning rule based on a back-propagation (BP) algorithm that can be applied to a hardware-based deep neural network using electronic devices that exhibit discrete and ...limited conductance characteristics. This adaptive learning rule, which enables forward, backward propagation, as well as weight updates in hardware, is helpful during the implementation of power-efficient and high-speed deep neural networks. In simulations using a three-layer perceptron network, we evaluate the learning performance according to various conductance responses of electronic synapse devices and weight-updating methods. It is shown that the learning accuracy is comparable to that obtained when using a software-based BP algorithm when the electronic synapse device has a linear conductance response with a high dynamic range. Furthermore, the proposed unidirectional weight-updating method is suitable for electronic synapse devices which have nonlinear and finite conductance responses. Because this weight-updating method can compensate the demerit of asymmetric weight updates, we can obtain better accuracy compared to other methods. This adaptive learning rule, which can be applied to full hardware implementation, can also compensate the degradation of learning accuracy due to the probable device-to-device variation in an actual electronic synapse device.
Rickettsiae constitute a group of arthropod-borne, Gram-negative, obligate intracellular bacteria that are the causative agents of diseases ranging from mild to life threatening that impact on ...medical and veterinary health worldwide.
A total of 6,484 ticks were collected by tick drag from June-October 2013 in the southwestern provinces of the Republic of Korea (ROK) (Jeollanam, n = 3,995; Jeollabuk, n = 680; Chungcheongnam, n = 1,478; and Chungcheongbuk, n = 331). Ticks were sorted into 311 pools according to species, collection site, and stage of development. DNA preparations of tick pools were assayed for rickettsiae by 17 kDa antigen gene and ompA nested PCR (nPCR) assays and the resulting amplicons sequenced to determine the identity and prevalence of spotted fever group rickettsiae (SFGR).
Haemaphysalis longicornis (4,471; 52 adults, 123 nymphs and 4,296 larvae) were the most commonly collected ticks, followed by Haemaphysalis flava (1,582; 28 adults, 263 nymphs and 1,291 larvae), and Ixodes nipponensis (431; 25 adults, 5 nymphs and 401 larvae). The minimum field infection rate/100 ticks (assuming 1 positive tick/pool) was 0.93% for the 17 kDa antigen gene and 0.82% for the ompA nPCR assays. The partial 17 kDa antigen and ompA gene sequences from positive pools of H. longicornis were similar to: Rickettsia sp. HI550 (99.4-100%), Rickettsia sp. FUJ98 (99.3-100%), Rickettsia sp. HIR/D91 (99.3-100%), and R. japonica (99.7%). One sequence of the partial 17 kDa antigen gene for H. flava was similar to Rickettsia sp. 17kd-005 (99.7%), while seven sequences of the 17 kDa antigen gene obtained from I. nipponensis ticks were similar to R. monacensis IrR/Munich (98.7-100%) and Rickettsia sp. IRS3 (98.9%).
SFG rickettsiae were detected in three species of ixodid ticks collected in the southwestern provinces of the ROK during 2013. A number of rickettsiae have been recently reported from ticks in Korea, some of which were identified as medically important. Results from this study and previous reports demonstrate the need to conduct longitudinal investigations to identify tick-borne rickettsiae and better understand their geographical distributions and potential impact on medical and veterinary health, in addition to risk communication and development of rickettsial disease prevention strategies.
In this paper, we reviewed the recent trends on neuromorphic computing using emerging memory technologies. Two representative learning algorithms used to implement a hardware-based neural network are ...described as a bio-inspired learning algorithm and software-based learning algorithm, in particular back-propagation. The requirements of the synaptic device to apply each algorithm were analyzed. Then, we reviewed the research trends of synaptic devices to implement an artificial neural network.
We investigate the characteristics of a synaptic imitation device using a thin-film transistor (TFT)-type NOR flash memory cell with a half-covered floating gate. The long-term potentiation (LTP) and ...long-term depression (LTD) required for the operation of the spike-timing-dependent plasticity (STDP) algorithm are implemented using the proposed pulse scheme. Unsupervised learning is successfully demonstrated by applying the STDP learning rule through software MATLAB simulation reflecting the LTP/LTD characteristics of the fabricated TFT-type NOR flash memory array. We present the learning and recognition processes of <inline-formula> <tex-math notation="LaTeX">28\times28 </tex-math></inline-formula> MNIST handwritten digit patterns. First, STDP learning in a single-neuron string (<inline-formula> <tex-math notation="LaTeX">784\times1 </tex-math></inline-formula>) is investigated, after which STDP learning is demonstrated in a multineuron array (<inline-formula> <tex-math notation="LaTeX">784\times10 </tex-math></inline-formula>) with a lateral inhibition function to demonstrate the ability of multipattern learning and recognition. Meanwhile, we investigate the key factors of STDP unsupervised learning. Finally, an approach is suggested to implement a hardware neural network using the conventional CMOS technology for STDP unsupervised learning as a visual pattern recognition system.
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