Synthesis of cuprous oxide nanocubes combined with chitosan nanoparticles and its application to p-nitrophenol degradation

For the first time, cuprous oxide nanocubes (Cu2O NCBs) were successfully combined with chitosan nanoparticles (CS NPs) to generate Cu2O NCBs/CS NPs composites material with highly optical property and photocatalytic activity using a simple and eco-friendly synthetic approach at room temperature for 30 min. The synthesized Cu2O NCBs NPs/CS NPs were determined characterizations by Ultraviolet-visible spectroscopy (UV-vis), Fourier transform infrared spectroscopy (FTIR), X – ray Diffraction (XRD),  Transmission Electron Microscope (TEM) and Energy-dispersive X-ray spectroscopy (EDX). Results show that the Cu2O NCBs/CS NPs composites have an average particle size of ~3-5 nm; in which, Cu2O has the form of nanocubes (Cu2O NCBs) with size ~3-4 nm and chitosan nanoparticles with spherical shape (CS NPs) with size ~4-5 nm. In addition, the percent (%) composition of elements present in Cu2O NCBs/CS NPs composites material have been obtained respective: Cu (23.99%), O (38.18%), and C (33.61%). Moreover, Cu2O NCBs/CS NPs composites material was also investigated for photocatalytic activity applied in p-nitrophenol degradation. The obtained results showed that the catalytic capability of Cu2O NCBs/CS NPs for p-nitrophenol reduction reached the highest efficiency >55% in the treatment time of 25 min, and this efficiency was higher than that result of using ZnO@chitosan nanoparticles (ZnO@CS NPs) catalyst under the same conditions for comparison

Autophagy in Human Embryonic Stem Cells

Autophagy (macroautophagy) is a degradative process that involves the sequestration of cytosolic material including organelles into double membrane vesicles termed autophagosomes for delivery to the lysosome. Autophagy is essential for preimplantation development of mouse embryos and cavitation of embryoid bodies. The precise roles of autophagy during early human embryonic development, remain however largely uncharacterized. Since human embryonic stem cells constitute a unique model system to study early human embryogenesis we investigated the occurrence of autophagy in human embryonic stem cells. We have, using lentiviral transduction, established multiple human embryonic stem cell lines that stably express GFP-LC3, a fluorescent marker for the autophagosome. Each cell line displays both a normal karyotype and pluripotency as indicated by the presence of cell types representative of the three germlayers in derived teratomas. GFP expression and labelling of autophagosomes is retained after differentiation. Baseline levels of autophagy detected in cultured undifferentiated hESC were increased or decreased in the presence of rapamycin and wortmannin, respectively. Interestingly, autophagy was upregulated in hESCs induced to undergo differentiation by treatment with type I TGF-beta receptor inhibitor SB431542 or removal of MEF secreted maintenance factors. In conclusion we have established hESCs capable of reporting macroautophagy and identify a novel link between autophagy and early differentiation events in hESC

HMU fluorinze mouthwash enhances enamel remineralization: An in vitro study

BACKGROUND: Fluoride therapy has long been used extensively to prevent dental caries. Fluoride appears in variety of dental care products such as mouthrinse, dentifrice, gel, etc. HMU fluorinze is the first mouthwash containing fluoride in Vietnam. AIM: This research was conducted to evaluate the efficacy of HMU Fluorinze mouthwash on remineralizing enamel in laboratory conditions. METHODS: 20 third molars teeth were cleaned and covered with nail polish , except for a 3x3 mm square on their buccal surfaces. These teeth went through two steps: demineralization using Coke and remineralization for 20 days: 1) using standard calcifying solution (control group) and 2) using standard calcifying solution + HMU Fluorinze mouthwash 2 times/day (experimental group). The mineralization index of enamel structure after demineralization and remineralization was assessed by DIAGNOdent pen 2190. RESULTS: The mineralization indexes of the control group and experimental group at baseline were 3.65 ± 0.76 and 3.35 ± 0.64, after demineralization were in turn of 21.78 ± 4.48 and 20.25 ± 2.26; and after remineralization were 6.30 ± 1.03 and 3.90 ± 1.24. The different figures  between the two groups after remineralization shows statistical significance (p<0.01). Group B using HMU fluorinze mouthwash after 20 days did not differ from the original results (p = 0.272), in contrast with the control group (p<0.01). CONCLUSIONS: HMU fluorinze mouthwash has better mineralization effect than standard calcifying solution

Effects of water scarcity awareness and climate change belief on recycled water usage willingness: Evidence from New Mexico, United States

The global water crisis is being exacerbated by climate change, even in the United States. Recycled water is a feasible alternative to alleviate the water shortage, but it is constrained by humans’ perceptions. The current study examines how residents’ water scarcity awareness and climate change belief influence their willingness to use recycled water directly and indirectly. Bayesian Mindsponge Framework (BMF) analytics was employed on a dataset of 1831 residents in Albuquerque, New Mexico, an arid inland region in the US. We discovered that residents’ willingness to use direct recycled potable water is positively affected by their awareness of water scarcity, but the effect is conditional on their belief in the impacts of climate change on the water cycle. Meanwhile, the willingness to use indirect recycled potable water is influenced by water scarcity awareness, and the belief in climate change further enhances this effect. These findings implicate that fighting climate change denialism and informing the public of the water scarcity situation in the region can contribute to the effectiveness and sustainability of long-term water conservation and climate change alleviation efforts

Synchronous PD Control Using a Time Delay Estimator for a Four-Degree-of-Freedom Parallel Robot in Practice

This paper presents a synchronous proportional derivative (PD) control method using a time delay estimator (SPD-TDE) for a four-degree-of-freedom (DOF) parallel robot in practice. The proposed control is a method that is developed from a synchronous PD control method combined with a time delay estimator to guarantee the tracking objectives and synchronous requirements of the robot. Firstly, the synchronous PD control method is designed by defining cross-coupling errors. A cross-coupling error is determined by incorporating the tracking error and deviation of tracking error among two adjacent joints or synchronous errors. Then, the asynchronous problem between the kinematic chains is solved and guarantees that the goal of synchronicity is achieved. Consequently, to improve the tracking performance of the robot, a time delay estimator is used to estimate and eliminate the uncertainty components of the system, such as modeling errors and actuator faults. In addition, the Lyapunov theory is also used to demonstrate the stability and robustness of the proposed control method. Finally, a testbench 4-DOF parallel robot is built, and the controllers are embedded in the control board from MATLAB Simulink using the Waijung block set library to operate the robot preset trajectory tracking. The experimental results of the proposed control method for the 4-DOF parallel robot are compared with those obtained using other controllers to prove its effectiveness

Comparative study of soil properties under various cultivation regimes of different crops

Establishment of cover crops is an effective way to reverse the soil fertility decline, which can be caused by a range of inappropriate traditional agriculture practices, particularly tillage and inorganic fertiliser application. In this study, soil properties were assessed under various cultivation regimes of different crops, including legumes, grass, and nursery natural rubber (NR) trees (Hevea brasiliensis Muell. Arg.), in southern Vietnam. The crops studied had all been growing for 7 years commencing in 1999, on light-textured Acrisols. Soils under the cultivation regime of creeping legumes including 'Calopogonium caeruleum', 'Pueraria phaseoloides', and 'Stylosanthes gracilis' had significantly higher carbon (C) and nitrogen (N) concentrations and porosity than soils under the other management types studied. Soils under 'Brachiaria ruziziensis' and 'P. phaseoloides' had the highest aggregate stability. Cultivation regimes with tillage, field traffic, and inorganic fertilisers applied to nursery NR trees increased phosphorus (P) availability, but this was accompanied by increased soil compaction and reductions in most of the other soil properties analysed. Relative to the nursery NR cultivation, creeping-legume cultivation increased soil C concentration (by 95%), soil pHH2O (by 19%), macro-aggregates (by 29%), and porosity (by 8%). From principal component analysis, three soil properties - soil organic carbon (SOC), porosity, and P availability - were selected as key indicators suitable for the evaluation of the effects of cultivation on soils. Establishment of 'C. caeruleum' and 'B. ruziziensis' was most effective in improving soil C content, and soil porosity was significantly higher under 'C. caeruleum' and 'P. phaseoloides'. These findings suggest that each cover crop had its own dominant agro-characteristics and that selection of a cover crop to either improve soil fertility or reduce compaction should be considered by farmers in this region

SO SÁNH SỰ SINH TRƯỞNG, NĂNG SUẤT VÀ PHẨM CHẤT CỦA 11 GIỐNG DƯA LÊ TRONG NHÀ LƯỚI VỤ XUÂN HÈ 2007

Mười một giống dưa lê F1 nhập nội được đánh giá năng suất, chất lượng và đặc tính nông học trồng trong nhà lưới tại Tra?i Thư?c nghiê?m Nông Nghiê?p, Trươ?ng Đa?i ho?c Câ?n Thơ từ tháng 3 - 5/2007. Kết quả thí nghiệm cho thấy có sự khác biệt qua phân tích thống kê về năng suất tổng và năng suất thương phẩm giữa các giống. Năng suất thương phẩm cao, ở mức 21,0 - 32,3 tấn/ha. Bốn giống dưa lê có triển vọng nhất la? Kim Cô Nương, Dưa lê 1864, Phương Thanh Thanh và Melon Hoàng hạt về phương diện trái đồng nhất, thời gian sinh trưởng ngắn 60 - 70 ngày, hàm lượng chất rắn hòa tan (độ ngọt) trong thi?t tra?i kha? cao (biê?n thiên10,3 - 12,4%). Giống Kim Nương (được dùng làm đối chứng bởi vì đã được trồng nhiều năm ở ViệtNam) tuy cho năng suất thấp nhất nhưng độ ngọt cao nhất, ăn giòn và có thời gian bảo quản lâu nhất.  Sâu bệnh hại trong nhà lưới không đáng kể trong suốt thời gian thực hiện thí nghiệm

On the use of both diaphragm and secant pile walls for a basement upgrade project in Vietnam

The paper presents a practical solution for upgrading the basement depth of a high-rise building in Ho Chi Minh (HCM) City, Vietnam. Finite element analysis, Plaxis 2D, was employed to simulate the construction site with two different kinds of walls, namely the diaphragm walls (DW) and the secant piles walls (SPW). In the project, SPW was installed next to the existing DW from the basement line, and further deep excavation could be proceeded . FEA results of the lateral deformation of DW and SPW as well as the ground surface settlement were compared with field observations. The comparison shows a good agreement between the numerical work and the field monitoring data. The overlapping lengths between two types of the wall were also investigated for design optimization. The current study can be used for future design projects under similar scenario

A Qualitative Investigation of the Interactions of Students with Graduate and Undergraduate TAs in General Chemistry Laboratories

A new teaching assistant model was adopted and qualitatively assessed for the general chemistry laboratory, in which both an undergraduate and a graduate teaching assistant provided instruction to students during the lab. Verbal interactions between graduate and undergraduate teaching assistants were recorded, transcribed, and coded using the modified Laboratory Observation Protocol for Undergraduate STEM (LOPUS). The codes were applied to capture how discussions, questioning, and explanations were conducted. In addition, the content discussed was coded to identify specific areas that pose challenges for students. Sizable differences were not observed between the number of interactions of the initiation, explanation, and questioning codes between graduate and undergraduate teaching assistants. Of the interactions, 77% focused on questions and discussions regarding the experimental setup. Discussions on the implications with regards to the effective use of undergraduate and graduate teaching assistants in chemistry laboratories are included