Approximating boundaries of causative sources is an important task in potential field interpretation. Many techniques have been proposed for approximating the edges including derivative and ...phase-based methods. The derivative-based methods cannot equalize the signal amplitudes, and although the phase-based methods do not have this problem, they maybe produce false edges, or the obtained edges are diffused. To overcome these problems, the ridges of some edge detection functions can be determined using the algorithms such as the Blakely and Simpson's algorithm or the curvature analysis algorithm. However, these algorithms cannot fully identify all the peaks of the data or produce some spurious ridges in output maps. In this study, we introduce an improved method to locate the peaks of the data. The efficiency of the algorithm is demonstrated on two synthetic gravity data, as well as real gravity data of the Vredefort dome area (South Africa). Compared with two traditional methods, the proposed algorithm produces more precise and detailed results.
•We introduced a method to locate the peaks of the data.•The method can be used to improve peaks detection.•Its efficiency is demonstrated on synthetic and real data of the Vredefort dome.
In the evaluation of magnetic field data, edge enhancement and detection techniques are important treatments for the interpretation of geological structures. In general geological sense, contiguity ...of deep and shallow magnetic sources leads to weak and intense anomalies that complicates the interpretation to disclose adjacent anomalous sources. Many of the existing filters for edge detection in magnetics mostly have the disadvantage that they require a reduction to pole transformation as the pre-process of the data or they cannot balance weak and intense anomalies and therefore fail in detecting edges of deep and shallow sources simultaneously. This study presents an improved edge detection filter LAS (logistic function of the analytical signal), based on the generalised logistic function configured by the ratio of derivatives of the analytical signal. This novel approach has the capability of reducing the dependence on the direction of the magnetization and also balancing anomalies of sources at different levels of depth. The feasibility of the method is examined on both theoretical and real data cases comparatively with some other methods that utilize the analytical signal in their basis. In comparison, the results demonstrate that the LAS method provides more accurate estimation of edge localization.
The in vivo studies of myocardial infarct using c-ki⁺/Lin⁻ cardiac stem cells (CSCs) are still in the early stage with margin or no beneficial effects for cardiac function. One of the potential ...reasons may be related to the absence of fully understanding the properties of these cells both in vitro and in vivo. In the present study, we aimed to systematically examine how CSCs adapted to in vitro cell processes and whether there is any cell contamination after long-term culture. Human CSCs were enzymatically isolated from the atrial appendages of patients. The fixed tissue sections, freshly isolated or cultured CSCs were then used for identification of c-kit⁺/Lin⁻ cells, detection of cell contamination, or differentiation of cardiac lineages. By specific antibody staining, we demonstrated that tissue sections from atrial appendages contained less than 0.036% c-kit⁺/Lin⁻ cells. For the first time, we noted that without magnetic activated cell sorting (MACS), the percentages of c-kit⁺/Lin⁻ cells gradually increased up to ∼40% during continuously culture between passage 2 to 8, but could not exceed >80% unless c-kit MACS was carried out. The resulting c-kit⁺/Lin⁻ cells were negative for CD34, CD45, CD133, and Lin markers, but positive for KDR and CD31 in few patients after c-kit MACS. Lin depletion seemed unnecessary for enrichment of c-kit⁺/Lin⁻ cell population. Following induced differentiation, c-kit⁺/Lin⁻ CSCs demonstrated strong differentiation towards cardiomyocytes but less towards smooth and endothelial cells. We concluded that by using an enzymatic dissociation method, a large number, or higher percentage, of relative pure human CSCs with stable expression of c-kit⁺ could be obtained from atrial appendage specimens within ∼4 weeks following c-kit MACS without Lin depletion. This simple but cost-effective approach can be used to obtain enough numbers of stably-expressed c-kit⁺/Lin⁻ cells for clinical trials in repairing myocardial infarction.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Friction and very high temperature are still the major challenges in hard machining technology and they greatly affect cutting efficiency. The application of the MQL (minimum quantity lubrication) ...method, using nanoparticles in order to improve the cooling lubrication performance of the base cutting oil, has proven to be a promising solution. Hence, this work aimed to investigate the effectiveness of Al2O3/MoS2 hybrid nanofluid and Al2O3 and MoS2 mono nanofluids in the hard turning of 90CrSi steel (60–62 HRC) under an MQL environment. The Box-Behnken experimental design was used for three input variables, including nanoparticle concentration, air pressure, and air flow rate. Their influences on surface roughness and cutting forces were studied. According to the obtained results, it was shown that the application of hybrid nano cutting oils in MQL contributes to achieving better hard machining performance than the use of mono nanofluids. In particular, a lower cutting temperature is reported and the values of surface roughness Ra, back force Fp, and cutting force Fc were smaller and more stable under Al2O3/MoS2 hybrid nanofluid MQL than those under Al2O3 and MoS2 mono nanofluid MQL due to an improvement in cooling lubrication characteristics. Thus, this work provides a novel approach to study hybrid nanofluids for MQL hard machining.
Although it is unclear how Zn
2+
cooperates with Cu
2+
in synergistic antibacterial activity, a 1:10 ratio of Cu
2+
/Zn
2+
atoms and ethylenediaminetetra-acetic acid and urea ligands can be used to ...form a chelation complex containing Cu
2+
and Zn
2+
. This study investigated the effects of the combination of Cu
2+
and Zn
2+
in chelation with EDTA and urea. The results were compared with the outcomes of either copper or zinc alone against gram-negative
Escherichia coli (E. coli
) and gram-positive
Staphylococcus aureus (S. aureus
) bacteria. The antibacterial activity was determined through MICs, disc diffusion method, and bacterial cell growth curves. In addition, bacterial destruction by this chelation complex has been observed through SEM images. The presence of copper ion and zinc ion inside the bacterial cells has been proved through EDS measurements. The obtained results allowed us to draw conclusions that the use of both Cu
2+
and Zn
2+
in a chelation complex with EDTA and urea enhances the antimicrobial activity against these bacteria. The bacterial inhibition of this complex was stronger than that of Cu
2+
alone chelated with EDTA or CuSO
4
solution by approximately 100-fold for
S. aureus
and 20-fold for
E. coli
.
During the winter period (October to March), air quality in northern Vietnam is strongly impacted by the northeast monsoon cycles, that create periodic changes in the air masses pathways and the ...meteorological conditions. In this work, an original approach is proposed to identify the main sources contributing to the degradation of air quality in Hanoi and quantify the share of local and imported pollution under the influence of the northeast monsoon. Firstly, semi-climatic trends in particle emissions in East Asia and mainland Southeast Asia were studied using outputs from the NAAPS model, that assimilates space-borne Aerosol Optical Depth (AOD) observations. From winter 2006/07 to winter 2010/11, the pollution plumes were most frequently located over the Indochina Peninsula, and the smoke partial AOD showed biomass burning activities (natural and anthropogenic) to be responsible. From winter 2011/12 to winter 2019/20 however, the pollution plumes were mostly observed over eastern China and to a lesser extent, Northern Vietnam, and the sulfate partial AOD indicated they came from coal-based industrial activities. Secondly, the impact of the northeast monsoon on the air masses origin was studied using HYSPLIT back-trajectories with clustering over the 14 winter periods. During regular winters, northeastern air masses predominated, which can bring pollution from eastern China and the industrial region surrounding Hanoi (Red River Delta). However, the existence of El Niño perturbed the air masses trajectories during three winters (2014/15, 2015/16 and 2018/19), bringing more western air masses and thus, causing a temporary decrease of the sulfate AOD and simultaneous increase of the smoke AOD over Hanoi. Thirdly, a method to classify the winter days and highlight the influence of cold surges on PM2.5 variability was built, relying only on Hanoi local wind and NAAPS AOD value. This classification allowed to estimate that long-range transport from China during the onset of cold surges caused an average increase of around 30% of the PM2.5 level in Hanoi. Additionally, the contribution of local pollution to the most severe pollution episodes, occurring during the persistence of cold surges, was estimated to be around 40% of the average PM2.5.
Display omitted
•The dominant sources of winter air pollution in Hanoi switched from biomass burning to industrial activities.•El-Nino episodes change the aerosol loads and the type of aerosols in Hanoi.•During cold surge onsets, long-range transport from China causes an average increase of ∼30% in PM2.5 concentrations.•The stagnation of local pollution during the cold surges persistence causes an average increase of ∼40% in level of PM2.5.
The ocotillol (OCT)‐type saponins have been known as a tetracyclic triterpenoid, possessing five‐ or six‐membered epoxy ring in the side chain. Interestingly, this type saponin was mostly found in ...Panax vietnamensis Ha et Grushv., Araliaceae (VG), hence making VG unique from the other Panax spp. Five OCT‐type saponins, majonoside R2, vina‐ginsenoside R2, majonoside R1, pseudoginsenoside RT4, vina‐ginsenoside R11, together with three protopanaxadiol (PPD)‐type saponins and four protopanaxatriol (PPT)‐type saponins from VG were evaluated for their antimelanogenic activity. All of isolates were found to be active. More importantly, the five OCT‐type saponins inhibited melanin production in B16‐F10 mouse melanoma cells, without showing any cytotoxicity. Besides ginsenoside Rd and ginsenoside Rg3 in PPD and notoginsenoside R1 in PPT‐type saponins, majonoside R2 was the most potent melanogenesis inhibitory activity in OCT‐type saponins. In this article, we highlighted antimelanogenic activity of OCT‐type saponins and potential structure–activity relationship (SAR) of ginsenosides. Our results suggested that OCT‐type saponins could be used as a depigmentation agent.
The n-hexane extract of Knema pachycarpa fruits (Myristicaceae family), exhibiting strong anti-acetylcholinesterase activity, was investigated by gas chromatography/mass spectrometry and then ...purified by column chromatography. Guided by GC/MS profiling and bioassay, chromatographic separations led to the isolation of five new compounds: two anacardic acid derivatives 1-2, two cardanol derivatives 3-4 and a cardol derivative 5, along with mixtures of known phenolic lipids 6-9. The chemical structures were determined by various spectroscopic methods. New isolated compounds 1-5 were evaluated for their cytotoxicity and anti-acetylcholinesterase activity. Cardanol 3 and cardol 5 were the most active compounds in the acetylcholinesterase inhibitory assay with IC
50
values of 2.60 ± 0.24 µM and 2.46 ± 0.23 µM, respectively. Cardanol 4 and cardol 5 showed moderate cytotoxicity against Hela and MCF-7 cancer cell lines with IC
50
values ranging from 31.36 ± 0.41 µM to 41.30 ± 2.49 µM.
Background
Antioxidant genes, such as superoxide dismutase (SOD), catalase (CAT), and nitric oxide synthase (NOS), play critical roles in spermatogenesis and sperm functions. Polymorphisms of ...antioxidant genes have been shown to be strongly associated with sperm quality which affects male fertility.
Methods
To investigate the association of antioxidant gene polymorphisms to male infertility in Vietnamese men, in this case–control study, using Sanger sequencing, we genotyped four variants SOD1:7958G>A, SOD2:c.47T>C, CAT:‐262C>T, and NOS3:‐786C>T.
Results and Conclusions
We identified SOD1:7958GA genotype and NOS3:‐786CT genotype in the infertility group were significantly higher than in the control with OR = 2.191 (95% CI: 1.226–3.915, p = 0.004) and OR = 3.135 (95% CI: 1.591–6.180, p < 0.001), respectively. We also detected that the frequency of the SOD2:c.47TC genotype was significantly higher in the male infertility group than in fertile men (OR = 1.941, 95% CI: 1.063–3.595, p = 0.029). Gene–gene interactions between the SNPs of SOD1, SOD2, and CAT might increase the risk of male infertility patients. In particular, patients carrying the SOD1:GA+AA, SOD2:TC+CC, and CAT:CT/TT genotype pattern have an increased risk of male infertility (OR = 7.614, p = 0.007). To our knowledge, this is the first study to evaluate the association between the SOD1:7958G>A polymorphism and male infertility. Further studies with larger sample sizes and more genes are needed to better assess the association between variants of antioxidant genes and male infertility.
The gene–gene interaction on male infertility. The patients, who carried both Superoxide dismutase 1 (SOD1) 7958GA and Manganese superoxide dismutase (SOD2) c.47TC genotypes had a 4.3‐fold; the patients with the SOD1:7958GA×CAT: ‐262CT genotype pattern had a 4.1‐fold. The patients, who had a combination of SOD1 7958GA+AA, SOD2 c.47TC+CC, and CAT ‐262CT+TT genotypes increased nearly 8 times the risk of infertility compared with the wild‐type carriers. Bold formats represent statistical significance (p < 0.05).
Background:
The B-type rafkinase (BRAF) V600E gene mutation plays an important role in the pathogenesis, diagnosis, and prognosis of thyroid carcinoma. This study was conducted to investigate the ...rate of the BRAF V600E mutation, the relationships between the BRAF V600E gene mutation and some immunohistochemical markers, and recurrence rate in patients with differentiated thyroid cancer.
Method:
The study was conducted by a descriptive and longitudinal follow-up method on 102 thyroid carcinoma patients at 103 Military Hospital, Hanoi, Vietnam. All patients were identified with the BRAF V600E gene mutation by real-time polymerase chain reaction.
Results:
The rate of BRAF V600E gene mutation in patients with thyroid cancer was 60.8%. Patients with BRAF V600E gene mutation had a significantly higher rate of positive cyclooxygenase 2 (COX-2) and Ki67 markers than those without the mutation (COX-2: odds ratio OR = 2.93; 95% confidence interval CI = 1.27-6.74, P = .011; Ki67: OR = 3.41; 95% CI = 1.31-8.88, P = .01). A statistically significant relationship was identified between the rate of BRAF V600E mutation and the rate of positive Hector Battifora mesothelial 1 (HBME-1) (B = −1.040; P = .037) and COX-2 (B = −1.123; P = .023) markers. The recurrence rate in patients with BRAF V600E gene mutation was significantly higher than that in those without the mutation (P = .007). The mean of the recurrence time of patients with BRAF V600E mutation was significantly lower than that in those without the mutation (P = .011).
Conclusions:
A high prevalence of BRAF V600E gene mutation was found in thyroid carcinoma patients. The rates of positive HBME-1, COX-2, and Ki67 markers were significantly correlated to BRAF V600E gene mutation. Patients with BRAF V600E gene mutation showed a significantly higher relapse rate and earlier relapse time than those without the mutation.
PDF
