A 4 × 4 Active Antenna Array with Adjustable Beam Steering.

An adjustable 4×4 antenna array with electrical beam steering and polarization control is presented. Here, adjustability means the ability to correct the beam steering angle post-calibration. The objective is to improve the steering accuracy which is critical in point-to-point communication as inaccuracy will cause transmission failure due to a missed target. The accuracy is enhanced by adjusting the beam steering angle in beamforming calculations. To execute this, the system is calibrated by measuring several unit cells of a partial 4×4 array structure at different voltage bias points and calculating an average model of the phase shift profile. This reduces the phase error from variations between components and robust beam steering is achieved. This technique is utilized in far-field measurements, and fairly accurate initial beam steering angles are achieved at 3 GHz. The accuracy is further improved by over or under steering the desired angle in the beamforming calculations to finally achieve the steering angle of interest with an accuracy of 2∘. Overall, the main beam is incrementally steered from 0∘ to 45∘ with the gain ranging from 4.7 dB to 2.8 dB. The polarization control is also demonstrated in horizontal and vertical directions for a linearly polarized wave.

Accumulation rates of natural radionuclides (40K, 210Pb, 226Ra, 238U, and 232Th) in topsoils due to long-term cultivations of water spinach (Ipomoea Aquatica Forssk.) and rice (Oryza Sativa L.) based on model assessments: A case study in Dong Nai province, Vietnam.

In topsoils, the activity concentrations of natural radionuclides (hereafter NRs) increase due to the addition of NRs from fertilizers, irrigation water, and air dust pollution. On the other hand, various physical-chemical and environmental processes such as radioactive decay, volatilization, leaching, erosion, and plant uptake were responsible for the decrease of the activity concentrations of NRs in the topsoils. In this study, behaviours of 40K, 210Pb, 226Ra, 238U, and 232Th in topsoils were modelled by the CEMC soil model and the HYDRUS-1D model. An exponential equation was proposed for estimating the accumulation rates of these radionuclides in the topsoils. Long-term accumulation of radionuclides was assessed for water spinach (Ipomoea Aquatica Forssk.) soil (hereafter VES) and rice (Oryza sativa L.) soil (hereafter RIS). We found that the current agricultural practices caused the increase of 40K activity concentration in the water spinach soil, and 40K, 210Pb, 226Ra, and 232Th activity concentrations in the rice soil. The accumulation rates of radionuclides were in the order 238U < 232Th < 226Ra < 210Pb < 40K. 25 years of cultivation with water spinach can increase/decrease + (165 ± 6) Bq of 40K, - (8.2 ± 0.7) Bq of 210Pb, - (4.3 ± 0.2) Bq of 226Ra, - (7 0.3 ± 0.3) Bq of 238U, and - (1.8 ± 0.1) Bq of 232Th in 1 kg soil. For rice cultivation, these values are + (1004 ± 39), + (3.3 ± 0.2), + (3.0 ± 0.2), - (5.1 ± 0.3), (2.2 ± 0.1) Bq kg-1 for 40K, 210Pb, 226Ra, 238U, and 232Th, respectively.

T7 exo-mediated FRET-breaking combined with DSN-RNAse-TdT for the detection of microRNA with ultrahigh signal-amplification.

A DSN-RNAse-TdT-T7 exo probing system allows the detection of miRNA 21 with very high sensitivity (LOD = 2.57 fM) and selectivity-the result of (i) avoiding the false-positive signal from miRNA reacting with TdT polymerase and (ii) signal amplification occurring through a FRET-breaking mechanism involving T7 exo.

Modelling the mitigation speeds of 137Cs, 90Sr and 131I in the topsoils and assessment of the radiological hazards.

Fate modelling of artificial radionuclides (ARs) in top soils are necessary to assess the radiological effects to population. Among ARs, 137Cs, 90Sr and 131I are very important since the large abundances in the environment. In this study, the fates of 137Cs, 90Sr and 131I in the surface soil layers were simulated by the soil model which was developed by the Canadian Centre for Environmental Modelling and Chemistry (CEMC). The scenario that 137Cs, 90Sr and 131I contaminated in topsoil in the exclusion of Fukushima Daiichi nuclear power plant (NPP) accident was evaluated. The results show the expected time for the minimum hazardous level of exposure. It is 115.5 days after the exposure, when the total effective dose is 1 mSv y-1 in which 0.46 mSv y-1 from ingestion and 0.54 mSv y-1 from gamma exposure. Hazard levels due to exposure progresses are varied in order gamma exposure (82.14%) > ingestion (17.47%) > inhalation (0.39%). The hazard levels from radionuclides are varied in order 137Cs (63.34%) > 131I (33.48%) > 90Sr (3.18%).

Splenic Artery Embolization in Conservative Management of Blunt Splenic Injury Graded by 2018 AAST-OIS: Results from a Hospital in Vietnam.

Purpose: This study was conducted to evaluate the results of conservative management of blunt splenic trauma according to the American Association for the Surgery of Trauma-Organ Injury Scale (AAST-OIS) in 2018 by embolization. Methods: This observational study included 50 patients (42 men and 8 women) with splenic injury who underwent multidetector computed tomography (MDCT) and embolization. Results: According to the 2018 AAST-OIS, 27 cases had higher grades than they did according to the 1994 AAST-OIS. The grades of two cases of grade II increased to grade IV; those of 15 cases of grade III increased to grade IV; and four cases of grade IV increased to grade V. As a result, all patients underwent successful splenic embolization and were stable at discharge. No patients required re-embolization or conversion to splenectomy. The mean hospital stay was 11.8±7 days (range, 6-44 days), with no difference in length of hospital stay among grades of splenic injury (p >0.05). Conclusion: Compared with the AAST-OIS 1994, the AAST-OIS 2018 classification is useful in making embolization decisions, regardless of the degree of blunt splenic injury with vascular lacerations visible on MDCT.

Treatment for removing radium in soil and groundwater.

The results of 226Ra activity concentration measurements in 50 soil and groundwater samples in Ninh Son region, Vietnam were evaluated in the present study. Average activity concentration in the soils was significantly higher than the worldwide average concentration in soils published by UNSCEAR, 2008. 90% of groundwater samples had concentrations of 226Ra that were higher than the USEPA drinking water standard. The results showed that there was a linear correlation between the 226Ra radioactivity in the soils and the concentration of 226Ra in the groundwater samples. The procedure for removal of 226Ra from soil and groundwater samples was built upon the chemistry behavior of radium. 226Ra in contaminated groundwater samples was removed by using MnO2 fiber. The removal efficiency of 226Ra reached ∼ 91% for the groundwater samples and ∼ 70% for the soil samples. Chemical removal of 226Ra from soils was investigated using a three-step extraction procedure (Easily leachable and exchangeable, Acid-reducible, and Oxidisable-organic). A moderate mobility of 226Ra (22-52%) was noted and mainly found in acid-reducible fractions, which suggests that 226Ra is mainly bound to Fe/Mn oxides and hydroxides. A multiple regression indicates that the 226Ra removal efficiency appears to be significantly dependent on Fe/Mn and organic matter content.

RNA Polymerase-Mediated Stepwise RNA-Primed RNA Polymerization for Site-Specific Multiple Labeling into RNA: A Fluorescence Resonance Energy Transfer Probe Detects the Structural Change of an RNA G-Quadruplex.

In this paper, we report a stepwise RNA-primed RNA polymerization method for the site-specific incorporation of multiple fluorescent moieties into RNA, mediated by an RNA polymerase. A screen of several RNA polymerases revealed that T7 RNA polymerase was the only one that functioned in the RNA-primed RNA polymerization. In the first fluorescence labeling step, a fluorescent rUthioTP residue was incorporated directly into the RNA using T7 RNA polymerase; the second fluorescence labeling step was performed using a post-labeling strategy: directly introducing an rUamiTP residue into RNA, using T7 RNA polymerase, and then reacting with ylidenemalononitrile enamine (P3). The whole process for the site-specific introduction of the multiple labeled moieties was performed through stepwise RNA-primed RNA polymerization. Interestingly, the resulting multiple-labeled RNA exhibited fluorescence resonance energy transfer (FRET) between the two fluorescent labels in the RNA. We optimized the FRET-breaking point in the RNA by changing of distance between the two fluorescent labels and then used this property for the detection of the structural change of the RNA. The FRET signal increased in intensity upon the transformation of the RNA from a single-strand structure to the G-quadruplex. This approach for site-specific FRET labeling into RNA using RNA polymerase suggests the possibility of performing other diverse site-specific modifications at predefined positions in RNA.

Propargylamine-selective dual fluorescence turn-on method for post-synthetic labeling of DNA.

We have developed a propargylamine-selective dual fluorescence turn-on system, using ylidenemalononitrile enamines, for post-synthetic DNA labeling, allowing the direct monitoring of DNA using dual emission in living cells.

Levels of 226Ra in groundwater samples collected in Phu Yen province, Vietnam associated with health risks to local population and impacts on the maize (Zea mays L.) soil.

Groundwater is a major source of drinking water and agricultural water in some regions of the world. However, it contains a high level of 226Ra that is potentially hazardous to human health and the environment. Normally, the activity concentration of 226Ra in groundwater is determined to assess the quality of groundwater that can be used as drinking water. There are few studies on the accumulation of 226Ra in the agricultural soil due to irrigation with groundwater. In this study, levels of 226Ra were determined on over 60 groundwater samples collected from the public water supply wells in Phu Yen province, Vietnam. Besides assessment of the health risks to population due to drinking groundwater samples, the impact of groundwater irrigation to the maize field in the study area was studied. For this purpose, two chemical fate models were applied and the comparison of their results was performed. Based on the model assessments, we predicted that the present agricultural practices increased the 226Ra activity concentration in the maize soil, and the level of 226Ra activity concentration in the topsoil can exceed the recommended level at 11.4 years of the present agricultural practices on the maize soil.

Corrigendum to "Speed Improvement in Image Stitching for Panoramic Dynamic Images during Minimally Invasive Surgery".

[This corrects the article DOI: 10.1155/2018/3654210.].

Site-specific incorporation of multiple units of functional nucleotides into DNA using a step-wise approach with polymerase and its application to monitoring DNA structural changes.

We have developed a new method, a step-wise approach with polymerase, for site-specific incorporation of multiple units of functional nucleotides into DNA to form hairpin secondary structures. The fluorescence of the resulting DNA incorporating the functional nucleotides varied upon transitioning from single-strand to hairpin and duplex structures.

Soil radon gas in some soil types in the rainy season in Ho Chi Minh City, Vietnam.

Field experiments on soil radon and radium concentrations were carried out in eighteen locations in Ho Chi Minh City, Vietnam. Soil radon depth profiles (10-100 cm) of loam, sand and clay soil samples in the rainy season were measured using RAD7 radon detector. Mean concentrations of 222Rn and 226Ra were found to be 28.6 ±â€¯2.0 Bq.kg-1 and (1.56 ±â€¯0.06) × 104 Bq.m-3 in clay soil while they are 31.2 ±â€¯2.5 Bq.kg-1 and (1.15 ±â€¯0.05) × 104 Bq.m-3 in loam soil. They are 30.7 ±â€¯2.0 Bq.kg-1 and (9.37 ±â€¯0.52) × 103 Bq.m-3 in sandy soil, respectively. Values of radon diffusion length and diffusion coefficient for different soils were obtained using semi-empirical fit method linked to the poor diffusion of gas in clay soil (0.2 × 10-6 m2 s-1), the moderate diffusion coefficient (0.9 × 10-6 m2 s-1) in loam and good diffusion of radon gas in sandy soil (1.4 × 10-6 m2 s-1). An unexpectedly unclear linear relation was found between soil radon concentration and radium content. The grain size smaller than 0.1 mm was dominant reason for the lowest (0.15 ±â€¯0.01) and highest (0.40 ±â€¯0.03) values emanation coefficient for sand and clay soil, respectively. A strong positive correlation was found between radon concentration and soil pH level leads to soil pH is an indirect dynamic parameter affecting the migration of radon in soil.

Speed Improvement in Image Stitching for Panoramic Dynamic Images during Minimally Invasive Surgery.

Minimally invasive surgery (MIS) minimizes the surgical incisions that need to be made and hence reduces the physical trauma involved during the surgical process. The ultimate goal is to reduce postoperative pain and blood loss as well as to limit the scarring area and hence accelerate recovery. It is therefore of great interest to both the surgeon and the patient. However, a major problem with MIS is that the field of vision of the surgeon is very narrow. We had previously developed and tested an MIS panoramic endoscope (MISPE) that provides the surgeon with a broader field of view. However, one issue with the MISPE was its low rate of video stitching. Therefore, in this paper, we propose using the region of interest in combination with the downsizing technique to improve the image-stitching performance of the MISPE. Experimental results confirm that, by using the proposed method, the image size can be increased by more than 160%, with the image resolution also improving. For instance, we could achieve performance improvements of 10× (CPU) and 23× (GPU) as compared to that of the original method.

Radon and radium concentrations in drinkable water supplies of the Thu Duc region in Ho Chi Minh City, Vietnam.

The results of (222)Rn and (226)Ra activity measurements in drinkable water supplies of the Thu Duc region in Ho Chi Minh City, Vietnam, are presented in this paper. The measurements were performed using a RAD 7 radon detector manufactured by Durridge Company, Inc. Mean concentrations of (222)Rn and (226)Ra were found to be 0.11±0.01Bql(-1) and 0.11±0.02Bql(-1) in 14 drinking water samples. They are 0.12±0.01Bql(-1) and 0.10±0.02Bql(-1) in 15 tap water samples, respectively. The mean (222)Rn concentration of 1.40±0.03Bql(-1) in the 20 groundwater samples of this study is also lower than the WHO advised level of 100Bql(-1). Fifty percent of groundwater samples analysed have (226)Ra levels in excess of the USEPA recommended maximum contaminant level of 0.185Bql(-1). The occurrence of elevated concentrations of (226)Ra in groundwater samples was explained by pH and alkaline conditions.