Search

Abstract Background Pseudomonas aeruginosa is well known for its intrinsic ability to resist a wide range of antibiotics, thus complicates treatment. Thus, understanding the response of the pathogen to antibiotics is important for developing new therapies. In this study, proteomic response of P. aeruginosa to the commonly used anti-pseudomonas antibiotics, ceftazidime (Caz) and meropenem (Mem) was investigated. Methods P. aeruginosa ATCC 9027, an antibiotic-susceptible strain, was exposed to sub-MIC values of antibiotics either Caz or Mem for 14 days to obtain E1 strains and then cultured in antibiotic-free environments for 10 days to obtain E2 strains. Proteomes of the initial and E1, E2 strains were identified and comparatively analyzed using isobaric tags for relative and absolute quantitation (iTRAQ) in cooperation with nano LC–MS/MS. Noted up and down-regulated proteins were confirmed with quantitative reverse transcriptase PCR (qRT-PCR). Results Overall, 1039 and 1041 proteins were identified in Caz and Mem-exposed strains, respectively. Upon antibiotic exposure, there were 7–10% up-regulated (Caz: 71, Mem: 85) and down-regulated (Caz: 106, Mem: 69) proteins (1.5-fold change cut-off). For both Caz and Mem, the DEPs were primarily the ones involved in metabolic process, membrane, virulence, protein synthesis, and antibiotic resistance in which proteins involved in antibiotics resistance tended to be up-regulated while proteins involved in protein synthesis and metabolic process were down-regulated. Noted proteins included beta-lactamase AmpC which was up-regulated and OprD which was down-regulated in both the antibiotic-exposed strains. Besides, biofilm formation related proteins TssC1 and Hcp1 in Caz- exposed strains and the membrane/ periplasmic proteins Azu and PagL in Mem-exposed strains were found significantly down-regulated. qRT-PCR results confirmed the expression change of AmpC, Hcp1 and OprD proteins. Conclusion Exposure of Pseudomonas aeruginosa to sub-MIC values of Caz and Mem resulted in around 10% change in its proteome. Not only proteins with confirmed roles in antibiotic resistance mechanisms changed their expression but also virulence- associated proteins. Both Caz and Mem response involved up-regulation of AmpC and down-regulation of OprD. While TssC1 and Hcp1 were responsible for Caz response, Azu and PagL were more likely involved in Mem response.

Abstract Background Canine parvovirus type 2 (CPV‐2) is known as the primary etiological agent cause of acute gastroenteritis, myocarditis and death of canids worldwide. In Vietnam, although CPV‐2 infection and its outbreaks are the most important risk factors of the canine's health concern, lack of available information about the molecular epidemiology of the CPV‐2. Objectives In this study, the complete coding sequences of 10 CPV‐2 strains collected from dogs vaccinated with CPV‐2 vaccination were analysed to better understand the genomic characteristics of the current circulating CPV‐2 in Vietnam. Methods Ten CPV‐specific PCR‐positive rectal swab samples were collected from dogs with acute symptoms of haemorrhagic diarrhoea and vomiting in Vietnam in 2019. The complete coding sequences of these CPV strains were analysed to determine their phylogeny and genetic relationship with other available CPV strains globally. Results Analysis of the VP2 gene sequences demonstrated that the studied strains belonged to the new CPV‐2c variants with the unique mutations at amino acids 5Ala‐Gly and 447Iso‐Met. Phylogenetic tree analysis indicated that the studied strains share a common evolutionary origin with the current CPV‐2c strains circulating in dogs in Asia countries, including China, Thailand, Taiwan and Mongolia, in recent years. Low sequence identity between the studied strains and commercial vaccine strains was observed. Conclusions This study provides deep insights into the molecular characteristics, genetic diversity, and evolution of circulating CPV‐2 strains in Vietnam. We recommend more studies to estimate the effectiveness of the CPV vaccine and the need to continue developing other effective vaccination essential to better control the widespread of these new CPV‐2 variants.

AbstractThis study investigates the roles of management experience and management practices towards innovation activities across ASEAN nations. Notably, the moderating role of the female CEOs in the management experience management practices—innovation relationship is also examined. The data came from the World Bank’s Enterprise Survey, consisting of 180,000 enterprises worldwide. This study extracted data from seven economies in ASEAN (Vietnam, Thailand, Indonesia, Philippines, Malaysia, Laos, and Cambodia). To deal with the hierarchical/multilevel structure of the study’s data set, the study uses the multilevel mixed-effects ordered logit model. The findings reveal that both management practices and management experience have positive impacts on innovation activities, particularly product innovation. Furthermore, this paper highlights the positive moderating role of female CEOs in the management experience management practices—innovation relationship.

The Bat Xat district in the Lao Cai province of Vietnam has enormous potential for resources of copper and rare earth minerals. In fact, exploration and exploitation activities for these minerals have brought about positive economic benefits to this area in recent years. However, this activity also brings about negative impacts on the environment and the surrounding population. The mineral deposits in this area contain a significant content of radioactive substances like uranium and thorium that radiate radon (222Rn) and thoron (220Rn). Therefore, the aim of this study is to investigate the distribution of radon as a function of depth of geological objects in the study areas. Results of this study showed that radon concentration has an exponential distribution with soil depth with R2 ranging from 0.87 to 0.97. It was found that radon concentration in sand was higher than that in clay and soils mixed with gravels. It was also shown that the density and moisture content of the soil is inversely proportional to the diffusion length of radon in the soil.

Radon and its isotopes are inert gases as they do not interact with any chemical compounds. Compared with thoron (220Rn) and radon-219 (219Rn), the risk of radioactive exposure of radon-222 (222Rn) is very high due to its long half-life of 3.8 d, while the half-life of 220Rn is 55 sec and of 219Rn is 4 sec. As a gas, radon can escape from the surfaces of ore, minerals, and rocks, then dissolve into groundwater and move very far from the formation site. While all these radioisotopes emit alpha radiation, Rn-222 is the most important as it is the main factor behind dangerous doses to the respiratory tract that are harmful to human health. Survey results of radon concentration in the air and retrospective data (from 2017 to 2019) on the health of residents and workers near and in the rare earth mines Dong Pao and Muong Hum, as well as the Sin Quyen copper mine, illustrated the health characteristics of the people involved in the northwestern mineral mines (Lao Cai - Lai Chau) that are exposed to radon. At the Dong Pao and Muong Hum rare earth mines, as well as the Sin Quyen copper mine, residents and workers were exposed to high concentrations of radon gas and thus developed some related illnesses such as respiratory, urological, digestive, genetic, and neurological diseases. Assessing the risk of pulmonary tuberculosis and estimating the average death rate from lung cancer with radon exposure shows that, in the surveyed area, the risk value is high (0.046) compared to other regions of Vietnam. However, it is within the limits allowed by the United States Environmental Protection Agency (EPA).

Understanding the colonization of Pseudomonas aeruginosa (P. aeruginosa) in healthy humans is useful for future prevention and treatment of P. aeruginosa infection. This study aimed to investigate the prevalence and risk factors of of P. aeruginosa colonization in healthy humans. At the same time, the virulence of the isolated P. aeruginosa was also studied. In the study, 609 Vietnamese volunteers (310 females and 299 males, age range of 2 to 73 years), who had no acute infection or disease symptoms participated at the time of sample collection. Samples were taken from the throat, nostrils, and outer ears. P. aeruginosa was found in 19 participants (3.12%, 95% CI: 0.017–0.045), mainly from the throat (11/19, 57.89%). Participants with a history of sinusitis were 11.57 times more likely to be colonized with P. aeruginosa than participants without a history of sinusitis (OR: 11.57, 95% CI: 4.08–32.76, p-value < 0.0001, Fisher’s Exact test). Age and sex were not significantly associated with P. aeruginosa colonization. Among 16 P. aeruginosa isolates used in virulence tests, 100% (16/16) were positive for the synthesis of biofilm, pyocyanin, and siderophores; 93.75% (15/16) isolates were positive for the synthesis of gelatinase and protease; and 50% (8/16) isolates were positive for lipase. There were no differences in the pattern and range of virulence factors of P. aeruginosa isolates taken from participants with and without sinusitis history. P. aeruginosa colonized 3.12% of participants, and its presence was associated with sinusitis history.

The energy and spectral advantages of signals with phase shift keying predetermined their widespread use in modern digital navigation, communications and television systems. The use of such signals is the base of communication standards of DVB-S, DVB-S2 / S2X, GLONASS, CDMA, WiFi IEEE 802.11 and others. To increase the capacity of radio channels, multiple phase shift keying (MPSK) is applied. This increases the number of possible phase states of the signal and, thus, the information capacity of the channel symbol. However, such an increase greatly affects the noise immunity of MPSK signal reception. In the article the noise immunity of receiving signals with multiple phase shift keying in the presence of noise and phase-shift interference is analyzed by the methods of statistical radio engineering. The dependencies of bit error probability on the signal-to-noise ratio, on the interference intensity, on the relative transmission speed of the interference, and on its detuning relative to the center frequency of the spectrum of the useful signal are calculated. It is shown that signals with multiple phase shift keying are very strongly influenced by phase-shift interference, and this influence increases with increasing signal positionality. The degree of reduction of the noise immunity of the reception depends on the magnitude of the relative transmission rate of the interference and its intensity. The damaging effect of the phase-shift interference is most pronounced when it hits the main lobe of the signal spectrum. As the relative transmission rate increases, the interference becomes more broadband and pseudo-noise, and it affects even with very large frequency detuning somewhat decreasing in the region of the main lobe of the signal spectrum. This decrease seems natural, since the analyzed algorithm for receiving MPSK signals is optimal for the effects of noise interference.

African swine fever (ASF) is the cause of a recent pandemic that is posing a threat to much of the world swine production. The etiological agent, ASF virus (ASFV), infects domestic and wild swine, producing a variety of clinical presentations depending on the virus strain and the genetic background of the pigs infected. No commercial vaccine is currently available, although recombinant live attenuated vaccine candidates have been shown to be efficacious. In addition to determining efficacy, it is paramount to evaluate the safety profile of a live attenuated vaccine. The presence of residual virulence and the possibility of reversion to virulence are two of the concerns that must be evaluated in the development of live attenuated vaccines. Here we evaluate the safety profile of an efficacious live attenuated vaccine candidate, ASFV-G-ΔI177L. Results from safety studies showed that ASFV-G-ΔI177L remains genetically stable and phenotypically attenuated during a five-passage reversion to virulence study in domestic swine. In addition, large-scale experiments to detect virus shedding and transmission confirmed that even under varying conditions, ASFV-G-ΔI177L is a safe live attenuated vaccine.

With the increasing emphasis on circular economies, biogas has gradually become an important energy source, but the refinement of biogas to reduce CO2 concentrations and impurities is required. This study reports on a one-pot top-down route to easily obtain mesostructured zeolite for CO2 adsorption during the biogas refinement process. Combining surfactants with an acid/base treatment achieved a perforation effect and generated mesopores in the zeolite structure. The zeolite structure and the presence of mesopores in the material were confirmed via XRD and a pore-size distribution analysis.div>

In this paper, we present a rectangular metric from a partial rectangular metric and state some relations between them. As applications, we show that fixed point theorems on partial rectangular metric spaces may be deduced from fixed point theorems on rectangular metric spaces.

By bringing the computation and storage resources close proximity to the mobile network edge, mobile edge computing (MEC) is a key enabling technology for satisfying the Internet of Vehicles (IoV) infotainment applications’ requirements, e.g., video streaming service (VSA). However, the explosive growth of mobile video traffic brings challenges for video streaming providers (VSPs). One known issue is that a huge traffic burden on the vehicular network leads to increasing VSP costs for providing VSA to mobile users (i.e., autonomous vehicles). To address this issue, an efficient resource sharing scheme between underutilized vehicular resources is a promising solution to reduce the cost of serving VSA in the vehicular network. Therefore, we propose a new VSA model based on the lower cost of obtaining data from vehicles and then minimize the VSP’s cost. By using existing data resources from nearby vehicles, our proposal can reduce the cost of providing video service to mobile users. Specifically, we formulate our problem as mixed integer nonlinear programming (MINP) in order to calculate the total payment of the VSP. In addition, we introduce an incentive mechanism to encourage users to rent its resources. Our solution represents a strategy to optimize the VSP serving cost under the quality of service (QoS) requirements. Simulation results demonstrate that our proposed mechanism is possible to achieve up to 21% and 11% cost-savings in terms of the request arrival rate and vehicle speed, in comparison with other existing schemes, respectively.

Streptococcus suis is a pathogen of major economic significance to the swine industry and is increasingly recognized as an emerging zoonotic agent in Asia. In Vietnam, S. suis is the leading cause of bacterial meningitis in adult humans. Zoonotic transmission is most frequently associated with serotype 2 strains and occupational exposure to pigs or consumption of infected pork. To gain insight into the role of pigs for human consumption as a reservoir for zoonotic infection in southern Vietnam, we determined the prevalence and diversity of S. suis carriage in healthy slaughterhouse pigs. Nasopharyngeal tonsils were sampled from pigs at slaughterhouses serving six provinces in southern Vietnam and Ho Chi Minh City area from September 2006 to November 2007. Samples were screened by bacterial culture. Isolates of S. suis were serotyped and characterized by multi locus sequence typing (MLST) and pulse field gel electrophoresis (PFGE). Antibiotic susceptibility profiles and associated genetic resistance determinants, and the presence of putative virulence factors were determined. 41% (222/542) of pigs carried S. suis of one or multiple serotypes. 8% (45/542) carried S. suis serotype 2 which was the most common serotype found (45/317 strains, 14%). 80% of serotype 2 strains belonged to the MLST clonal complex 1,which was previously associated with meningitis cases in Vietnam and outbreaks of severe disease in China in 1998 and 2005. These strains clustered with representative strains isolated from patients with meningitis in PFGE analysis, and showed similar antimicrobial resistance and virulence factor profiles. Slaughterhouse pigs are a major reservoir of S. suis serotype 2 capable of causing human infection in southern Vietnam. Strict hygiene at processing facilities, and health education programs addressing food safety and proper handling of pork should be encouraged.

Between 2003 and 2005, highly pathogenic avian influenza A (H5N1) viruses caused large scale outbreaks in poultry in the Ho Chi Minh City area in Vietnam. We studied the prevalence of antibodies against H5N1 in poultry workers and cullers who were active in the program in Ho Chi Minh City in 2004 and 2005.Single sera from 500 poultry workers and poultry cullers exposed to infected birds were tested for antibodies to avian influenza H5N1, using microneutralization assays and hemagglutination inhibition assay with horse blood. All sera tested negative using microneutralization tests. Three samples showed a 1ratio80 titer in the hemagglutination inhibition assay.This study provides additional support for the low transmissibility of clade 1 H5N1 to humans, but limited transmission to highly exposed persons cannot be excluded given the presence of low antibody titers in some individuals.