Tạp chí Khoa học Tự nhiên Đại học Quốc gia Thành phố Hồ Chí Minh

The disorder of endometrial tissue regeneration is the main cause of uterine adhesions, amenorrhea, and infertility in women. Monthly changes in the endometrial cycle and injured uterine regeneration confirm the role of stem cells, hormonal regulation as well as endometrial tissue structure. In previous studies, the use of a single or combined stem cell therapy, hormone therapy, and scaffold transplantation had been increasingly emphasized. This paper presented the evaluatation of the role of the stem cell and matrix combination in the presence of estrogen hormone in endometrial regeneration on the human injured uterine tissue model. Human uterine tissue fragments were collected and mechanically damaged for in vitro modeling. The fibrin scaffolds were fabricated and combined with, respectively, human adipose tissue stem cells (hADSCs) and human bone marrow stem cells (hBMSCs) to be treated in an established injured model in conditions with or without estrogen. Histological assessments were performed to compare and confirm the regenerative effect of the treatments after 14 days of investigation. The results showed that there was no difference in the histological structure between the control treatment (no treatment) and the single treatment with stem cells. However, when stem cells were combined with fibrin matrix in the presence of estrogen, the uterine glands were formed where the layered structure of the endometrium was clearly demonstrated. In conclusion, the endometrial regenerating effect was well established by the combined treatment of these stem cells with fibrin scaffolds in the presence of estrogen. The combination of cells and scaffolds in tissue engineering therapy gradually showed the potential applications for in vitro studies, especially in the field of infertility treatment.

In this study, the effects of light and dark condition, sucrose concentration, and plant growth regulators on the in vitro growth of bulblet from Lily Sorbonne shoot were studied. Morphological, physiological and biochemical changes in the bulblet growth were analyzed. Shoots in the light condition developed into plant while shoots in continuous darkness formed bulblet. Sucrose (90 g/L) increased the size of scale and starch accumulation of bulb. 6-Benzylaminopurine (BA 1,5 mg/L) stimulated the divison of parenchyma cell. The combination of 90 g/L sucrose and 1,5 mg/L BA in dark condition stimulated the division and size of the parenchyma cells, which increase the number and size of scales and size and weight of the bulblet. Respiratory rate, zeatin content and starch accumulation were increased in the bulblet growth. The correlation of light condition, sucrose concentration, plant hormone, respiration rate, starch accumulation, and bulblet growth were discussed. The combination of 90 g/L sucrose, 1.5 mg/L BA and 0.5 zeatin mg/L in dark strongly induced the growth of in vitro Lily bulblet, especially the number of scale.

Synthesis of zinc oxide nanoparticles (ZnO) which was found to be effective catalyst for Friedel-Crafts benzoylation reaction in the presence of deep eutectic solvent (DES). The method is one of the most important intermediates for preparing fine chemicals in the field of pharmaceuticals, which is a tool for organic syntheses of aromatic ketones. ZnO precursor was prepared from Zn(CH3COO)2.2H2O and H2C2O4.2H2O, ZnO nanoparticles were characterized by using X-ray Powder Diffraction (XRD), Scanning Electron Microscope (SEM). The benzoylation of aromatic compounds and benzoyl chloride using nanoparticles ZnO/ [CholineCl][Urea]2, under microwave irradiation afforded the desired products in high yields and short reaction times. The catalyst/solvent could be recycled several times without loss of efficient catalytic activity.

Nowadays, rechargeable Li-ion batteries represent almost all human activities. Therefore, the requirements of battery optimization for power density, energy density, and cycle life are becoming necessary. Based on negative commercial graphite, graphite‒silicon composite (G‒Si) material has become a potential anode for Li-ion batteries due to its high specific capacity and energy density. This paper presented the investigation the electrochemical performance of the G‒Si composite in the carbonate based solvents which consisted of 1 M LiPF6 dissolving in the solvent of EC‒DMC 1:1 (v/v), EC‒DEC 1:1 (v/v), or EC‒EMC 1:1 (v/v). The results showed that the G‒Si composite delivered a high capacity of 616.0 mAh/g with the highest capacity retention of 64.2% (50 cycles) at the current density of 40 mA/g in the EC‒EMC 1:1 (v/v) solvent. However, when the current density was doubled (80 mA/g), the capacity of G‒Si in EC‒DEC 1:1 (v/v) rapidly decreased, while the capacity of the EC‒EMC 1:1 (v/v) maintained the highest. The EIS showed that the Rsf and Rct values in the EC‒DEC 1:1 (v/v) based electrolyte gradually increased with cycles which appropriated to the GCPL results. Besides, the intercalation diffusion mechanism of Li+ into the G‒Si composite confirmed that this process could be divided into two main regions where the diffusion coefficients were the minimum and related to the plateaus in the discharge curves of G‒Si material. The diffusion coefficient of G‒Si was of 10-6‒10-12 cm2/s which was the smallest in the EC‒DEC 1:1 (v/v) system.

Consider the model Y = X + Z , where Y is an observable random variable, X is an unobservable random variable with unknown density f , and Z is a random noise independent of X . The density g of Z is known exactly and assumed to be compactly supported. We are interested in estimating the m- fold convolution fm=f*...*f on the basis of independent and identically distributed (i.i.d.) observations Y1,..,Yn drawn from the distribution of Y . Based on the observations as well as the ridge-parameter regularization method, we propose an estimator for the function fm depending on two regularization parameters in which a parameter is given and a parameter must be chosen. The proposed estimator is shown to be consistent with respect to the mean integrated squared error under some conditions of the parameters. After that we derive a convergence rate of the estimator under some additional regular assumptions for the density f .

Thrombogenicity is one of the challenges when using membrane grafts in cardiovascular surgery. Therefore, this paper presented the fabrication of bovine pericardial scaffold immobilized with heparin in order to improve its antithrombogenicity for the application in the cardiovascular field. Heparin was immobilized on the scaffolds by the layer-by-layer method, based on the interaction of heparin and dihydroxy-iron (DHI). The structure, biochemistry, anticoagulation, and ability to support the endothelial cell attachment were evaluated to determine the effectiveness of the heparin immobilization. Histology staining and scanning electron microscopy images revealed the presence of heparin on the bovine pericardial scaffolds. The quantitative result demonstrated that the layer-by-layer method significantly increased the heparin content on bovine pericardial scaffolds. The heparin-immobilized scaffolds performed a good antithrombogenicity after direct incubation in the whole blood samples. This antithrombogenicity was maintained after 30 days of testing. Additionally, the scaffolds were shown to cause no cytotoxicity and support endothelial cell adhesion after 48 hours. These results indicated the potential of heparin-immobilized bovine pericardial scaffolds for the application in cardiovascular transplantation.

Solar cells based on hybrid organic – inorganic halide lead perovskite are potentially promising to be used in the near future. The quality of the perovskite thin film played an important role in the photovoltaic performance of perovskite solar cells. One strategy to improve the quality of the film was to utilize an additive into the precursor solution during the perovskite formation process. This paper presented the use of a quinonoid zwitterion compound at some concentrations from 0 to 2.0 mg.L-1 added to the PbI2 solution to synthesize the CH3NH3PbI3 perovskite thin film which was further implemented to fabricate solar cell devices. The perovskite films were analysed by X-ray diffraction, UV/Vis absorption spectroscopy and Scanning electron microscope and the obtained solar cell devices were characterized by current–voltage curve measurements. The results showed that the addition of the quinonoid zwitterion could increase the efficiency of the perovskite transformation with a film with more uniform morphology and less of voids, leading to a significant improvement of open circuit voltage values of the devices. The overall efficiency of the solar cells fabricated with a perovskite film using 0.5 mg.L-1 additive enhanced up to 2 % in comparison to those of non-additive ones.

In gamma spectrometry, the quantitative information about the composition of elements present in the experimental samples can be obtained from the efficiency calibration curve, the radioactivity, and the gamma emission intensity of the radioactive. The efficiency of the detector is often affected by the coincidence summing effect. The correction of the coincidence summing factors can be done through the software based on the efficiency transfer method or Monte Carlo simulation. In this study, two Monte Carlo simulation software, MCNP‒CP and PENNUC, were applied to calculate the coincidence summing factors of four radioactive 22Na, 60Co, 133Ba, and 134Cs by the simulation method. The calculated models from the benchmark with two types of detectors of n-type and p-type, using different source geometries such as point source, water, soil, and filter samples, were used. This study aimed to validate the spectral response as well as to compare the coincidence summing factors between MCNP‒CP and PENNUC. The results showed that the coincidence summing factors calculated by two simulation software gave a good agreement with an average relative deviation of less than 2%. The coincidence summing factors calculated by two simulation programs were verified by the statistical T-test with a linear correlation value of rxy = 0.995.

Lasianthus bidoupensis, belonging to Rubiaceae, has been recently found and has not been studied on chemical constituents and biological activities whereas species of the same genus have been used in traditional medicine and possessed diverse bioactivities. This paper reported the isolation and structural elucidation of organic compounds from the n-hexane extract of L. bidoupensis stems in order to give more chemical and biological information on this species. From the dried powder of L. bidoupensis stems, the crude extract was obtained by maceration of material in ethanol. This extract was separated into different polar ones by the method of liquid‒liquid extraction. The n-hexane extract, exhibited the strongest cytotoxic activity against MCF-7 cell line, was thus chosen to isolate the organic compounds by silica gel column chromatography. Five compounds were isolated as lupeol (1), 3-epi-betulinic acid (2), 3-epi-3-O-acetyl betulinic acid (3), 3-epi-oleanolic acid (4), and vergatic acid (5). The chemical structures of the isolated compounds were elucidated based on MS and NMR spectral data as well as a comparison of their NMR data with the published ones. Among them, compounds 2‒5 were reported in the genus Lasianthus for the first time and compound 3 showed the strongest MCF-7 cytotoxic activity with IC50 of 13.88±0.11 mg/mL.

Peanut is am essential legume and has many uses, such as producing oil, food, and fodder. However, with the negative effects of climate change, drought is one especially of the important issues that reduce the yield of peanut. Thus, in this study, the impact of drought stress on the peanut growth was investigated by using PEG-6000 to block pathways of water movement. The changes in morphological, physiological, and biochemical during the peanut growth under drought were analyzed. In the drought condition (-2 bar), the germination time of seed increased but the percentage of germination seeds decreased by approximately 50% compared to control. Besides, the shoot height, the number of leaves, the total leaf area, root length, and fresh weight were lower than that of control. Drought stress made the formation quickly of secondary xylem and phloem. Also, the process of lignification in the phloem parenchyma cell increased. These cell walls were much thicker than those in the control root. In the drought stress, the physiological and biochemical analysis showed that the content of chlorophyll a, leaf relative water content, and starch content reduced significantly in comparison to control. Similarly, the photosynthetic intensity, the activity of cytokinin, and gibberellin decreased. The reverse pattern can be seen in the content of carotenoid, epicuticular wax, proline, and total soluble sugar, respiratory intensity, the activity of catalase, auxin, and ABA activity.