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A magnetic multi-wall carbon nanotube (MCNTs) nanocomposite was synthesized and was used as an adsorbent for removal of oil from aqueous solutions. The MCNTs nanocomposite was composed of commercial multi-wall carbon nanotubes and iron oxide nanoparticles. The property of this magnetic adsorbent was characterized by scanning electron microscopy, X-ray diffraction and VSM. Adsorption characteristics of the MCNT nanocomposite was examined using diesel oil (DO) as adsorbate. The sorption capacity was affected significantly by the initial concentration of DO, sorbent amount and contact time. Batch experiments were conducted to investigate the affect of different DO initial concentration (ranging from 0.2 to 1.0%) and contact time (10 to 90 min) to the removal efficiency. This MCNTs nanocomposite can be recycled conveniently from water with the assist of an external magnet because of their exceptional properties.

Colistin is extensively used in animal production in many low- and middle-income countries. There is a need to develop methodologies to benchmark and monitor changes in resistance among mixed commensal bacterial populations in farms. We aimed to evaluate the performance of a broth microdilution method based on culturing a pooled Escherichia coli suspension (30-50 organisms) obtained from each sample. To confirm the biological basis and sensitivity of the method, we cultured 16 combinations of one colistin-susceptible and one mcr-1 encoded colistin-resistant E. coli in the presence of 2mg/L colistin. Optical density (OD600nm) readings over time were used to generate a growth curve, and these values were adjusted to the values obtained in the absence of colistin (adjusted Area Under the Curve, AUCadj). The median limit of detection was 1 resistant in 104 susceptible colonies [1st - 3rd quartile, 102:1 -105:1]. We applied this method to 108 pooled faecal samples from 36 chicken flocks from the Mekong Delta (Vietnam), and determined the correlation between this method and the prevalence of colistin resistance in individual colonies harvested from field samples, determined by the Minimum Inhibitory Concentration. The overall prevalence of colistin resistance at sample and isolate level (estimated from the AUCadj) was 38.9% [95%CI, 29.8-48.8%] and 19.4% (SD± 26.3%), respectively. Increased colistin resistance was associated with recent (2 weeks) use of colistin (OR=3.67) and other, non-colistin antimicrobials (OR=1.84). Our method is a sensitive and affordable approach to monitor changes in colistin resistance in E. coli populations from faecal samples over time.IMPORTANCE Colistin (polymyxin E) is an antimicrobial with poor solubility in agar-based media, and therefore broth microdilution is the only available method for phenotypic resistance. However, estimating colistin resistance in mixed Escherichia coli populations is laborious since it requires individual colony isolation, identification and susceptibility testing. We developed a growth-based microdilution method suitable for pooled faecal samples. We validated the method by comparing it with individual MIC of 909 E. coli isolates; we then tested 108 pooled faecal samples from 36 healthy chicken flocks collected over their production cycle. A higher level of resistance was seen in flocks recently treated with colistin in water, although the observed generated resistance was short-lived. Our method is affordable, and may potentially be integrated into surveillance systems aiming at estimating the prevalence of resistance at colony level in flocks/herds. Furthermore, it may also be adapted to other complex biological systems, such as farms and abattoirs.

Colistin (polymyxin E) is an antimicrobial with poor solubility in agar-based media, and therefore, broth microdilution is the only available method for determining phenotypic resistance. However, estimating colistin resistance in mixed Escherichia coli populations is laborious, since it requires individual colony isolation, identification, and susceptibility testing., Colistin is extensively used in animal production in many low- and middle-income countries. There is a need to develop methods to benchmark and monitor changes in resistance among mixed commensal bacterial populations in farms. We aimed to evaluate the performance of a broth microdilution method based on culturing a pooled Escherichia coli suspension (30 to 50 organisms) obtained from each sample. To confirm the biological basis and sensitivity of the method, we cultured 16 combinations of one colistin-susceptible and one mcr-1-carrying colistin-resistant E. coli isolate in the presence of 2 mg/liter colistin. Readings of optical density at 600 nm (OD600) over time were used to generate a growth curve, and these values were adjusted to the values obtained in the absence of colistin (adjusted area under the curve [AUCadj]). The median limit of detection was 1 resistant in 104 susceptible colonies (1st to 3rd quartile, 102:1 to 105:1). We applied this method to 108 pooled fecal samples from 36 chicken flocks from the Mekong Delta (Vietnam) and determined the correlation between this method and the prevalence of colistin resistance in individual colonies harvested from field samples, determined by the MIC. The overall prevalences of colistin resistance at the sample and isolate levels (estimated from the AUCadj) were 38.9% (95% confidence intervals [CI], 29.8 to 48.8%) and 19.4% ± 26.3% (± values are standard deviations [SD]), respectively. Increased colistin resistance was associated with recent (2 weeks) use of colistin (odds ratio [OR] = 3.67) and other, noncolistin antimicrobials (OR = 1.84). Our method is a sensitive and affordable approach to monitor changes in colistin resistance in E. coli populations from fecal samples over time. IMPORTANCE Colistin (polymyxin E) is an antimicrobial with poor solubility in agar-based media, and therefore, broth microdilution is the only available method for determining phenotypic resistance. However, estimating colistin resistance in mixed Escherichia coli populations is laborious, since it requires individual colony isolation, identification, and susceptibility testing. We developed a growth-based microdilution method suitable for pooled fecal samples. We validated the method by comparing it with individual MIC determinations for 909 E. coli isolates; we then tested 108 pooled fecal samples from 36 healthy chicken flocks collected over their production cycle. A higher level of resistance was seen in flocks recently treated with colistin in water, although the observed generated resistance was short-lived. Our method is affordable and may potentially be integrated into surveillance systems aiming at estimating the prevalence of resistance at colony level in flocks/herds. Furthermore, it may also be adapted to other complex biological systems, such as farms and abattoirs.

Several novel of polymethoxyquercetin Mannich base derivatives (2-7) were synthesized through O-methylation and based on Mannich reaction with various secondary amines and formaldehyde, starting from abundant and inexpensive natural sources quercetin. All the synthesized compounds were confirmed by 1H NMR, 13C NMR and MS techniques and the synthetic compounds were test for antiproliferative activities on human cervical carcinoma Hela cell line by the standard CCK-8 assay, the result showed that most of the target compounds exhibited moderate to potent antiproliferative activities on Hela (cervical carcinoma) cell which is comparable to the positive control cis-Platin. Among them, polymethoxyquercetin Mannich base derivatives (2) showed the strongest activity (IC50 3.80 μM), they are potential and selective anticancer agent and worthy of further development

Colistin is extensively used in animal production in many low- and middle-income countries. There is a need to develop methodologies to benchmark and monitor changes in resistance in commensal bacterial populations in farms. We aimed to evaluate the performance of a broth microdilution method based on culturing a pooled Escherichia coli suspension (30-50 organisms) from each sample. In order to confirm the biological basis and sensitivity of the method, we prepared 16 standard suspensions containing variable ratios of colistin-susceptible and mcr-1 encoded colistin-resistant E. coli which were grown in 2mg/L colistin. The optical density (OD600nm) readings over time were used to generate a growth curve, and were adjusted to the values obtained in the absence of colistin. The median limit of detection of the method was 1 colistin-resistant in 104 susceptible colonies [1st - 3rd quartile, 1:102 – 1:105]. We applied this method to 108 pooled faecal samples from 36 chicken flocks in the Mekong Delta (Vietnam) over the production cycle. The correlation between this method and the prevalence of colistin resistance in individual colonies harvested from field samples, determined by the Minimum Inhibitory Concentration (MIC), was established. The overall prevalence of colistin resistance at sample and isolate level was 38.9% and 19.4%, respectively. Increased colistin resistance was associated with recent (2 weeks) use of colistin and other, non-colistin antimicrobials (OR=3.67 and OR=1.84, respectively). Our method is a sensitive and affordable approach to monitor changes in colistin resistance in pooled E. coli populations from faecal samples over time.IMPORTANCEColistin (polymyxin E) is an antimicrobial with poor solubility properties, and therefore broth microdilution is the only appropriate method for testing colistin resistance. However, estimating colistin resistance in commensal mixed Escherichia coli populations is laborious since it requires individual colony isolation, identification and susceptibility testing. We developed a growth-based microdilution method suitable for pooled faecal samples. We validated the method by comparing it with results from individual MIC testing of 909 E. coli isolates. We used the method to investigate phenotypic colistin resistance in 108 pooled faecal samples from 36 healthy chicken flocks, each sampled three times over the production cycle. A higher level of resistance was seen in flocks recently supplemented with colistin in drinking water, although the observed generated resistance was short-lived. Our method is affordable, and may potentially be integrated into surveillance systems aiming at estimating the prevalence of resistance at colony level in flocks/herds. Furthermore, it may also be adapted to other complex biological systems, such as farms and abattoirs.

Fronthaul is associated with a new and different type of Radio Access Network architecture consisting of centralized Baseband Units (BBUs) and Remote Radio Units (RRUs) [2] . In order to meet the fifth-generation wireless (5G) challenges of increased traffic and data flows, a new connection protocol for the fronthaul network called Evolved Common Public Radio Interface (eCPRI) has been published. This paper aims to design a system that supports this interface to transmit data from the BBUs to RRUs in 5G Radio Access Network (RAN). By referencing the specification of eCPRI, we develop a hardware system on FPGA to encapsulate and extract required headers for this protocol. The system is compatible with a 10Gb Ethernet subsystem that provides 10Gb Ethernet MAC and a Physical Interface. On top of the system, we develop drivers and applications to configure and run the system.

DDoS attacks often happen in cloud servers and cause a devastating problem. However, an increasing number of Internet of Things (IoT) devices makes us not ignore the influence of large-scale DDoS attacks from IoT devices. In this paper, we propose a machine learning-based on a multi-layer IoT DDoS attack detection system, including IoT devices, IoT gateways, SDN switches, and cloud servers. Firstly, we build eight smart poles with various sensors on our campus and collect sensor data as our datasets through wireless networks or wired networks. Next, we extract the features based on DDoS attack types. The feature selection can result in high accuracy DDoS attack detection in the real IoT environment. The experimental results show that our multi-layer DDoS detection system can accurately detect DDoS attacks. And the SDN controller can block venomous devices effectively according to blacklists from the results of our IoT DDoS attacks detection system.

The unpromoted and B-promoted 10%Ni/SBA-15 catalysts synthesized via sequential incipient wetness impregnation approach were assessed for combined steam and CO2 reforming of methane (CSCRM) at various reaction temperatures of 973–1073 K and stoichiometric feed composition. An expected and noteworthy drop in mean NiO crystallite size and BET surface area with boron promotion from 1% to 5%B loading could be due to the agglomeration of B2O3 particles and deboration reaction during calcination and hence blocking mesopores of SBA-15 support at elevated B composition. The complete NiO reduction to metallic Ni0 form was achieved during H2 activation and the reduction temperature of NiO phase was shifted towards higher temperature with B-addition owing to enhancing interaction between the acidic B2O3 and basic NiO phases. For all reaction temperature employed, 3%B appeared to be the optimal promoter loading in terms of reactant conversions and 3%B-10%Ni/SBA-15 catalyst revealed the greatest H2 yield (69.4%) at 1073 K. In addition, CH4 and CO2 conversions were enhanced about 23.2% and 32.4%, correspondingly with rising reaction temperature from 973 to 1073 K. Ratio of H2 to CO varied from 1.26 to 2.71 and the desired H2/CO ratio of about 2 favored for Fischer-Tropsch synthesis was achieved on 3%B-10%Ni/SBA-15 sample at 973 K. Boron promoter suppressed graphitic carbon formation and the amount of carbonaceous deposition was reduced about 4 times. Noticeably, 3%B-10%Ni/SBA-15 was also resilient to metallic Ni0 re-oxidation throughout CSCRM.

Excessive antimicrobial usage and deficiencies in hygiene in meat production systems may result in undesirable human health hazards, such as the presence of antimicrobial drug residues and non-typhoidal Salmonella (NTS), including antimicrobial resistant (AMR) NTS. Recently, Vietnam has witnessed the emergence of integrated intensive animal production systems, coexisting with more traditional, locally-sourced wet markets. To date no systematic studies have been carried out to compare health hazards in beef, pork and chicken in different production systems. We aimed to: (1) estimate the prevalence of antimicrobial residues in beef, pork and chicken meat; (2) investigate the prevalence and levels of NTS contamination; and (3) investigate serovar distribution and AMR against critically important antimicrobials by animal species and type of retail (wet market vs. supermarket) in Vietnam. Fresh pork, beef and chicken meat samples (N = 357) sourced from wet markets and supermarkets in Ho Chi Minh City (HCMC), Hanoi and Dong Thap were screened for antimicrobial residues by PremiTest, and were further investigated by Charm II. Samples from HCMC (N = 113) were cultured using ISO 6579:2002/Amd 1:2007. NTS bacteria were quantified using a minimum probable number (MPN) technique. NTS isolates were assigned to serovar by Multilocus Sequence Typing (MLST), and were investigated for their phenotypic susceptibility against 32 antimicrobials. A total of 26 (7.3%) samples tested positive by PremiTest (9.5% beef, 4.1% pork and 8.4% chicken meat). Sulfonamides, tetracyclines and macrolides were detected by Charm in 3.1%, 2.8% and 2.0% samples, respectively. Overall, meat samples from wet markets had a higher prevalence of residues than those from supermarkets (9.6% vs. 2.6%) (p = 0.016). NTS were isolated from 68.4% samples from HCMC. Chicken samples from wet markets had by far the highest NTS counts (median 3.2 log MPN/g). NTS isolates displayed high levels of resistance against quinolones (52.2%) and β-lactams (49.6%), but low levels against 3rd generation cephalosporins (4.4%) and aminoglycosides (0.8%). The highest adjusted prevalence of multidrug resistance (MDR) corresponded to isolates from chicken meat and pork (OR 8.3 and 1.8, respectively) (baseline = beef). S. Kentucky was the most common serovar identified (11 from chicken, 1 from beef) and 91.7% isolates was MDR. 11/12 isolates corresponded to ST198, a worldwide-disseminated multi-resistant NTS clone. We recommend stepping up policy measures to promote responsible antimicrobial use in animal production, as well as awareness about withdrawal periods to limit the hazard of residues in animal products, and improving slaughtering/hygiene procedures to limit cross-contamination with NTS, particularly in poultry wet markets., Highlights • Antimicrobial residues were found in 7.3% meat samples (9.6% in meat from wet markets and 2.6% in meat from supermarkets). • Over two thirds (68.4%) of meat samples were contaminated with non-typhoidal Salmonella; 52.2% of isolates were multidrug resistant. • Chicken meat from wet markets had the highest loads of contamination with non-typhoidal Salmonella (median 3.2 log MPN/g in positive samples). • Multidrug resistance was highest in Salmonella from chicken meat, and lowest in beef; the type of retail was not linked to increased resistance. • The most commonly identified serovar was multidrug resistant Salmonella Kentucky ST198, with high levels resistance against β-lactams and quinolones.

The accurate assessment of antimicrobial use (AMU) requires relating quantities of active ingredients (AAIs) with population denominators. These data can be used to prioritize potential sources of selective pressure for antimicrobial resistance and to establish reduction targets. Here, we estimated AMU in Vietnam (human population 93.4 M in 2015), and compared it with European Union (EU) data (population 511.5 M in 2014). We extrapolated AMU data on each key animal species and humans from different published sources to calculate overall AMU (in tonnes) in Vietnam. We then compared these data with published statistics on AMU in the European Union (EU). A total of 3838 t of antimicrobials were used in Vietnam, of which 2751 (71.7%) corresponded to animal use, and the remainder (1086 t; 28.3%) to human AMU. This equates to 261.7 mg and 247.3 mg per kg of human and animal biomass, compared with 122.0 mg and 151.5 mg in the EU. The greatest quantities of antimicrobials (in decreasing order) were used in pigs (41.7% of total use), humans (28.3%), aquaculture (21.9%) and chickens (4.8%). Combined AMU in other species accounted for

We investigated antimicrobial residues, non-typhoidal Salmonella (NTS), Vibrio spp. and their associated antimicrobial resistance (AMR), in shrimps locally purchased in Ho Chi Minh City (Vietnam). In addition, we investigated the relationship between AMR in NTS, Vibrio spp. and antimicrobial residue in the same sample. A total of 40 samples of shrimp heads/shells from different retail sources was cultured using ISO 6579–1:2017 (NTS) and ISO/TS 21872–1:2007 (Vibrio spp.). Phenotypic antimicrobial susceptibility was investigated using Vitek (NTS, 34 antimicrobials) and disk diffusion (Vibrio spp., 12 antimicrobials). A total of 9 (22.5%) samples contained antimicrobial residue, including tetracyclines, fluoroquinolones, sulfonamides and macrolides (in 7.5%, 7.5%, 2.5% and 2.5% of samples, respectively). Shrimp samples from supermarkets had a higher prevalence of antimicrobial residue than those purchased in street markets (50% vs. 13.3%) (p = 0.049). A total of 30 (75%) samples were contaminated with NTS. All samples contained Vibrio spp., with V. parahaemolyticus being most common (87.5% samples). A total of 58.9% NTS isolates were multidrug resistant. With regards to the highest priority, critically important antimicrobials, the highest resistance corresponded to quinolones (14.4–47.8%), followed by 3rd and 4th generation cephalosporins (3.3–7.8%). Vibrio spp. isolates were characterised by their high resistance against ampicillin (82.7%) and 3rd generation cephalosporins (8.3–16.5%). Extended Spectrum Beta-Lactamase (ESBL) activity was detected in 28.1% V. parahaemolyticus isolates. Half of ESBL-positive V. parahaemolyticus strains harboured blaCTX-M1. We found an association between the presence of residues and the number of resistances for NTS (p = 0.075) and Vibrio spp. isolates (p = 0.093) from the same sample. These findings suggest that the presence of residues may contribute to the selection of AMR in foodborne pathogens in shrimps. Authorities should strengthen policies aiming at restricting inappropriate antimicrobial usage in shrimp farming, and step up monitoring of antimicrobial residues and food-borne pathogens at retail in Vietnam., Highlights • Highest prevalence of antimicrobial residues found in shrimps from supermarkets. • 75% samples were contaminated with non-typhoidal Salmonella (NTS). • Isolates from samples with antimicrobial residues had highest prevalence of phenotypic resistance. • Extended Spectrum Beta-Lactamase activity detected in 28.1% V. parahaemolyticus isolates.

International audience

The objectives of this research are to determine the optimum values of grinding wheel parameters. An optimization problem with manufacturing time as the objective function was solved. The initial wheel diameter, the wheel life, the radial grinding wheel wear per dress and the total depth of dressing cut were considered as the input factors in the present study. Moreover, their effects on the optimum replaced wheel diameter were explored based on the implementation of a simulation experiment. The obtained results showed that the optimum replaced wheel diameter can be calculated by employing the proposed regression equation.

This paper presents a study on the determination of the optimum gear ratios of a two-stage worm gearbox. To find the optimum gear ratios, an optimization problem was performed. Also, the reasonable gearbox structure was chosen as the objective function of the optimization problem. In addition, the effects of the input factors including the total gearbox ratio, the electric motor speed, and the output torque were investigated. Besides, a simulation experiment was designed and performed by computer programs to evaluate the influences of these input factors on the optimum gear ratios. Moreover, some models to calculate the optimum gear ratios of a two-stage worm gearbox were suggested. As these equations are explicit, the determination of the optimum gear ratios is accurate and uncomplicated.

This paper introduces an optimization study on determination of optimum replaced grinding wheel diameter in internal grinding process. In this study, the minimum manufacturing time was chosen as the objective of optimization problem. Also, several grinding parameters containing the initial grinding wheel diameter, the radial grinding wheel wear per dress, the total depth of dressing cut and the wheel life were taken into the investigation. In addition, to evaluate the influences of these input factors on the optimum replaced wheel diameter, a simulation experiment was conducted. Lastly, a regression model was presented for determination of the optimum replaced wheel diameter.

The paper presents a study on determining optimum gear ratios of mechanical driven systems using a two-stage helical gearbox with second stage double gear sets and a chain drive. In the study, an optimization problem with the objective function as the minimum system length was solved. In addition, the effects of the input parameters including the total gearbox ratio, the wheel face width coefficient, the allowable contact stress and the output torque on the optimal transmission ratios were evaluated by conducting a simulation experiment. Moreover, several equations to find the optimum gear ratios were proposed.

The article reports a study on identifying the optimum gear ratios of mechanical driven systems containing a two-stage helical gearbox with the first stage double gear sets and a chain drive. To find the optimum gear ratios, the minimum system length was chosen as the objective function of the optimization problem. Moreover, the input parameters including the total system ratio, the wheel face width coefficients of the first and the second stages, the allowable contact stress and the output torque and their impacts on the optimum ratios were explored based on the design and implementation of a simulation experiment. The obtained equations showed that the optimum gear ratios can be calculated precisely and conveniently.

Prediction of the surface quality of a manufacturing process has a very important role. Therefore, in this paper, a study on the prediction of surface roughness in turning process with the use of diamond insert was presented. Based on the results of previous studies, a new surface roughness model was formulated. In the model, the effects of the depth of cut, the nose radius of the insert, the feed rate, and the characteristics of the workpiece material were taken into account. The surface roughness calculated from the model has been successfully verified by an experiment. Hence, this proposed model can be used to predict the surface roughness in turning processes using diamond inserts.

This paper introduces an optimization study on the determination of the optimum replaced grinding wheel diameter for getting minimum manufacturing time in external grinding stainless steel. In the study, several input grinding parameters including the initial grinding wheel diameter, the total depth of dressing cut, the wheel life and the radial grinding wheel wear per dress. Also, to evaluate the effects of the input parameters on the optimum replaced wheel diameter, a simulation experiment was planned and conducted. Lastly, a regression model to calculate the optimum replaced wheel diameter was suggested.