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A 3D DEM model using Particle Flow Code (PFC3D) software was developed utilizing a bonded-ball flexible membrane approach to study cohesionless soil as a discontinuous discrete material. This approach is not yet widely used because of its complexity and high computational cost, but it allowed the authors to observe the stress-strain curves of triaxial specimens, to single out effects of individual factors on the strength and strain properties, and to observe the formation of the shear band and failure surface. The 3D model was calibrated and verified with experimental data, and a sensitivity analysis was carried out for the microparameters. Triaxial tests were simulated to observe the stress-strain curves and volumetric changes, as well as the strength parameters of soils consisting of spherical particles with different gradations but the same porosity. The authors investigated the effects of mean particle size, larger particle size, smaller particle size, and soil gradation on three soil parameters: peak deviatoric stress, internal friction angle, and dilatancy angle. Four different cases with different soil gradations and particle sizes were studied: a uniform soil, a soil with randomly created particle sizes, and two soils each contains two particle sizes. For two out of the four cases studied, peak deviatoric stress, internal friction angle, and dilatancy angle increased when the mean particle size D50 increased. For the other two cases, the parameters decreased when the mean particle size D50 increased. One important finding is that the relationships between particle size and deviatoric stress, internal friction angle, and dilatancy angle were found to be linear. These relationships can provide predictions on soil strength and strain properties when the particle size changes. Observations and discussions on the formation of shear bands during shear testing are also presented. A step-by-step delineation of the DEM model development is also presented with the development process of a flexible membrane carefully described.

In this paper, we propose a variational method for restoring images corrupted by multiplicative noise. Computationally, we employ the alternating minimization method to solve our minimization problem. We also study the existence and uniqueness of the proposed problem. Finally, experimental results are provided to demonstrate the superiority of our proposed hybrid model and algorithm for image denoising in comparison with state-of-the-art methods.

In situ g-C3N4@ZnO nanocomposites (with 0, 1, 3, 5, and 7 wt.% of g-C3N4 in nanocomposite) were synthesized via a one-pot hydrothermal method using precursors of urea, zinc nitrate hexahydrate, and hexamethylenetetramine. The g-C3N4@ZnO nanocomposites were characterized by X-ray diffraction, scanning electron microscope, diffuse reflectance spectroscopy, and photoluminescence spectroscopy. The photocatalyst activity of g-C3N4@ZnO nanocomposites was evaluated via methylene blue degradation experiment under visible light irradiation. The g-C3N4@ZnO nanocomposites showed an enhancement in photocatalytic activity in comparison to pure ZnO which increased with the g-C3N4 content (1, 3, 5, and 7 wt.%) in nanocomposites. The photocatalytic activity reached the highest efficiency of 96.8% when the content of g-C3N4 was 7.0 wt.%. Nanocomposite having 7.0 wt.% of g-C3N4 also showed good recyclability with degradation efficiency higher than 90% even in the 4th use. The improvement of photocatalytic activity could be attributed to the adsorption ability and effective separation of electron-hole pairs between g-C3N4 and ZnO. This work implies a simple method to in situ prepare the nanocomposite material of g-C3N4 and semiconductors oxide for photocatalyst applications with high efficiency and good recyclability.

Understanding structure at the interface between two-dimensional (2D) materials and 3D metals is crucial for designing novel 2D/3D heterostructures and improving the performance of many 2D material devices. Here, we quantify and discuss the 2D/3D interface structure and the 3D morphology in several materials systems. We first deposit faceted Au nanoislands on graphene and transition metal dichalcogenides, using measurements of the equilibrium island shape to determine values for the 2D/Au interface energy and examining the role of surface reconstructions, chemical identity, and defects on the grown structures. We then deposit the technologically relevant metals Ti and Nb under conditions where kinetic rather than thermodynamic factors govern growth. We describe a transition from dendritic to faceted islands as a function of growth temperature and discuss the factors determining island shape in these materials systems. Finally, we show that suspended 2D materials enable the fabrication of a novel type of 3D/2D/3D heterostructure and discuss the growth mechanism. We suggest that emerging nanodevices will utilize versatile fabrication of 2D/3D heterostructures with well-characterized interfaces and morphologies.

Different tungsten oxide nanocrystals were synthesized via facile hydrothermal process – one-step and free of additives - at different reaction temperatures and a highly acidic environment. The phase transformation of samples, followed by the change of morphology and optical properties, was observed as the reaction temperature varied from room temperature to 220oC. The crystal phase transformed from monoclinic WO3∙2H2O to orthorhombic WO3∙H2O, then to monoclinic WO3 as the reaction temperature increased from room temperature to 100 ⁰C, then to 220 ⁰C. Corresponding to the phase transformation, the optical bandgap increased from 2.43 eV to 2.71 eV, and the morphology varied from nanoplate to nanocuboid. The effect of the reaction temperature on the phase transformation was assigned to the dehydration process, which became stronger as the reaction temperature increased. These results gave an insight into the phase transformation and implied a simple method for manipulating the crystal phase and morphology of tungsten oxide nanostructure for various applications.

This study aims to provide data on usual walking speed in individuals aged 80 years or older and determine the association between walking speed and related factors in community-dwelling older adults. A cross-sectional study design was conducted to measure walking speed on community-dwelling elders aged 80 years or older in Soc Son district, Vietnam. Walking speed was assessed by a 4-Meter Walk Test with a usual-pace walking mode. Health-related characteristics of participants including risk of falls (The Timed Up and Go test, activities of daily living (ADL), instrumental activities of daily living (IADLs), cognitive impairment (Mini-Cog test) and frailty syndrome (The Reported Edmonton Frail Scale (REFS)). Multiple logistic regression was used to analyze the association between a slow walking speed and selected factors. A total of 364 older people were recruited, and the majority were female (65.4%). The overall average walking speed was 0.83 ± 0.27 m/s. The proportion of participants with a slow walking speed (

Introduction: A common problem in image restoration is image denoising. Among many noise models, the mixed Poisson-Gaussian model has recently aroused considerable interest. Purpose: Development of a model for denoising images corrupted by mixed Poisson-Gaussian noise, along with an algorithm for solving the resulting minimization problem. Results: We proposed a new total variation model for restoring an image with mixed Poisson-Gaussian noise, based on second-order total generalized variation. In order to solve this problem, an efficient alternating minimization algorithm is used. To illustrate its comparison with related methods, experimental results are presented, demonstrating the high efficiency of the proposed approach. Practical relevance: The proposed model allows you to remove mixed Poisson-Gaussian noise in digital images, preserving the edges. The presented numerical results demonstrate the competitive features of the proposed model.

Co-packaging of optics and electronics for data center switches has been proposed to reduce system-level power consumption by minimizing power-hungry electrical interconnects. Co-packaging optical components near high-temperature electronics, however, can diminish their performance and reliability. Moreover, limitations of the switch environment, such as restricted footprint, power, and number of fiber attachments can limit practical co-packaging implementations. Here, we study four architectures for co-packaged optical interfaces using either single- or multi-wavelength light sources that can be either external to or integrated with the optical interfaces. We model the temperature- and current-dependent performance and reliability of the sources and calculate the link budget for switch bandwidths up to 102.4 Tb/s. We compare architectures based on coherent and direct detection and find that all coherent detection architectures support 102.4 Tb/s switching with over 13 dB link budget, while most direct detection architectures scale to 51.2 Tb/s or 102.4 Tb/s switching with link budgets less than 5 dB. In addition, we demonstrate that external-source architectures require wavelength-division multiplexing at lower switch bandwidths and consequently have link budgets 1-5 dB lower than integrated source architectures. Further, we demonstrate that higher-power lasers can scale external architectures to 102.4 Tb/s switching with over 4 dB link budgets. Finally, for 51.2 Tb/s switching, we show that a reduction in integrated source temperature improves link budgets by 2-4 dB and direct detection external-source architectures can achieve greater than 5 dB link budget with fewer than 300 fiber attachments.

We describe a robust and scalable method to produce crinkled hexagonal boron nitride (h-BN) nanofoam from graphite in a single-step, leapfrog-like process. The conversion is based on carbothermic r...

In this note, we provide a large class of moderate expanders with the exponents 3 8 and 5 13 over arbitrary finite fields and prime fields, respectively. Our main ingredients are an energy result due to the third, fourth, sixth listed authors and Shen (2019) and a theorem on two-variable expanding functions given by Hegyvari and Hennecart (2009). Using the same approach, we derive similar results in the setting of finite local and principal rings.

Let $\mathbb{F}_q$ be an arbitrary finite field, and $\mathcal{E}$ be a set of points in $\mathbb{F}_q^d$. Let $\Delta(\mathcal{E})$ be the set of distances determined by pairs of points in $\mathcal{E}$. By using the Kloosterman sums, Iosevich and Rudnev proved that if $|\mathcal{E}|\ge 4q^{\frac{d+1}{2}}$, then $\Delta(\mathcal{E})=\mathbb{F}_q$. In general, this result is sharp in odd-dimensional spaces over arbitrary finite fields. In this paper, we use the recent point-plane incidence bound due to Rudnev to prove that if $\mathcal{E}$ has Cartesian product structure in vector spaces over prime fields, then we can break the exponent $(d+1)/2$, and still cover all distances. We also show that the number of pairs of points in $\mathcal{E}$ of any given distance is close to its expected value., Comment: Final version!

In this study, a weight-control bender element system has been developed to investigate the impact of matric suction equalization on the measurement of small strain shear modulus (Gmax) during an air-drying process. The setup employed is capable of measuring the shear wave velocity and the corresponding Gmax of the soil sample in either an open system in which the soil sample evaporates freely or in a closed system that allows the process of matric suction equalization. The comparison between measurements of Gmax in the open and closed systems revealed underestimations of Gmax when matric suction equalization was ignored due to the nonuniform distribution of water content across the sample cross-sectional area. This study also investigated the time required for matric suction equalization tse to be established for samples with different sizes. The experimental results indicated two main mechanisms driving the matric suction equalization in a closed system during an air-drying process, namely the hydraulic flow of water and the flow of vapour. While the former played the key role when the micropores were still saturated at the high range of water content, effects of the latter increased and finally dominated when more air invaded the micropores at lower water contents.

The stress Electrocardiogram (ECG) gives more efficient results for the diagnosis of cardiovascular diseases, which may not be apparent when the patients are at rest. However, the noise produced by the movement of the patient and the environment often contaminates the ECG signal. Motion artifact is the most prevalent and difficult type of interference to filter in stress test ECG. It corrupts the quality of the desired signal thus reducing the reliability of the stress test. In this work, we first describe a quantitative study of adaptive filtering for processing the stress ECG signals. The proposed method uses the motion information obtained from a 3-axis accelerometer as a noise reference signal for the adaptive filter and the optimal weight of the adaptive filter is adjusted by the Modified Error Data Normalized Step-Size (MEDNSS) algorithm. Finally, the performance of the proposed algorithm is tested on the stress ECG signal from the subject.

Let Fq be an arbitrary finite field of order q and let M2(Fq) be the ring of all 2×2 matrices with entries in Fq. In this article, we study detS for certain types of subsets S⊂M2(Fq). For i∈Fq, let Di be the subset of M2(Fq) defined by Di:={x∈M2(Fq):det(x)=i}.

Deep Learning (DL) plays an important role in machine learning and artificial intelligence. DL is widely applied in many fields with high dimensional data, including natural language processing, image recognition. High dimensional data can lead to problems in machine learning such as overfitting, degradation of accuracy. To address these issues, some methods, such as Principal Components Analysis (PCA), principal component regression (PCR), Multi-class Linear Discriminant Analysis (MLDA), were proposed to reduce dimensions of the data and computational complexity simultaneously. The drawback of these methods is that they only work well on data distributed on the plane. In the case of the data distributed on the hyper-sphere, such as objects moving in space, the processing results are not so good as expected. In this paper, we propose the use of Conformal Geometric Algebra (CGA) to extract features and simultaneously reduce the dimensionality of a dataset for human activity recognition using Recurrent Neural Network (RNN). First, human activity data in a 3-dimensional coordinate system is pre-processed and normalized by calculating deviations from the mean coordinate. Next, the data is transformed to vectors in CGA space and its dimensions are reduced to return the feature vectors. Finally, we use the RNN model to train feature vectors. Empirical results performed on the CMU eight actions dataset show that the CGA combined with RNN gave the best test results of 92.5%.

5-FU is one of the key drugs in the treatment of gastric cancer (GC). Much evidence has shown that cancer stem cells (CSCs) play a key role in the acquisition of drug resistance. The organoid is a novel 3D cell culture system technology that sustains stem-cell-driven formation of near-physiological, self-renewing tissues using specific niche factors in a dish. In this study, we established GC organoids (GCOs) and gradually treated them with higher concentrations of 5-FU. We successfully harvested four 5-FU-resistant GCOs, which were supported by significant changes in the expression of molecules related to 5-FU metabolism. We then performed microarray analysis using three normal gastric organoids and three pairs of 5-FU-resistant and parental GCOs. Through the comparison of expression profiles and further validation, we chose KHDRBS3 as a target gene. We found KHDRBS3 to be an independent prognostic factor in GC patients, especially in GC patients treated with 5-FU chemotherapy. We also determined that KHDRBS3 might play an important role in the acquisition of stem cell-like features, such as multi-drug resistance and organoid formation, by regulating CD44 variant expression. We found KHDRBS3, which is thought to play an important role in the acquisition of characteristics of CSCs in GC, to be a promising candidate marker for predicting therapeutic effect and prognosis in GC patients.

Purpose The high prevalence of chronic pain and difficulties in pain management in older people are challenging for healthcare providers globally. Patient satisfaction regarding pain management is one of the measures to assess efficacy of pain control as well as healthcare services. Thus, our study aimed to evaluate the older patients' satisfaction with pain management and its associated factors in Vietnam. Patients and methods A cross-sectional study was conducted at National Geriatric Hospital, Hanoi, Vietnam from May to October 2018. Face-to-face interviews were conducted on 495 older patients with chronic pain by using a structured questionnaire. The Pain Treatment Satisfaction Scale (PTSS) was used to assess the level of satisfaction with pain management. A Tobit regression model was used to estimate factors associated with satisfaction toward pain management. Results The mean total satisfaction score was 1.77 (SD= 0.22). Older patients were most satisfied with the aspect of side effects of pain relief medication (mean=0.66, SD=0.56). On the contrary, they were most dissatisfied with information provided about pain and its treatment and efficacy of pain relief medication. Outpatients were less satisfied with information provided, the impact of current medication and pain management in general compared to inpatients. The regression model showed that patients with severe pain tended to be more dissatisfied with pain management than those with no pain. Conclusion This study indicated that the general satisfaction with chronic pain management in older patients was quite good especially in the aspect of pain medication's side effects. However, dissatisfactory factors remained, including information provided about pain and efficacy of current pain medication. Intensive training regarding pain in geriatric care, health education communication for older people, and improved quality of medical services should be performed to ensure the quality of pain management, especially in the older population.

Anh Trung Nguyen,1,2 Hai Quang Pham,3,4 Thanh Xuan Nguyen,1,2,5 Thu Thi Hoai Nguyen,1,2 Huong Thi Thu Nguyen,1,2 Tam Ngoc Nguyen,1,2 Dung Thi Kim Dinh,1 Hai Thanh Phan,3,4 Son Hoang Nguyen,6 Bach Xuan Tran,7,8 Carl A Latkin,8 Roger CM Ho,9,10 Cyrus SH Ho,9 Thang Pham,1,2 Huyen Thi Thanh Vu1,2 1Hanoi Medical University, Hanoi, Vietnam; 2National Geriatric Hospital, Hanoi, Vietnam; 3Institute for Global Health Innovations, Duy Tan University, Da Nang, Vietnam; 4Faculty of Medicine, Duy Tan University, Da Nang 550000, Vietnam; 5Dinh Tien Hoang Institute of Medicine, Hanoi, Vietnam; 6Center of Excellence in Health Services and System Research, Nguyen Tat Thanh University, Ho Chi Minh, Vietnam; 7Institute for Preventive Medicine and Public Health, Hanoi Medical University, Hanoi 100000, Vietnam; 8Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA; 9Department of Psychological Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore; 10Institute for Health Innovation and Technology (iHealthtech), National University of Singapore, Singapore, SingaporeCorrespondence: Huyen Thi Thanh VuDepartment of Geriatrics, Hanoi Medical University, 01 Ton That Tung, Hanoi, VietnamTel +84 913531579Email vuthanhhuyen11@hmu.edu.vnBackground: Diabetes-related complications have become increasingly prevalent and complicated to manage, especially among frail older adults with co-morbidities, poor physical function, and impaired cognition. Thus, knowledge, attitude, and practice (KAP) of elderly diabetic patients play an essential role in controlling the disease and its complications.Patients and Methods: A cross-sectional study was conducted on 176 diabetic patients at the outpatient clinics, National Geriatric Hospital, Hanoi, Vietnam from August to November 2015. Patients’ knowledge, attitude, and practice regarding diabetes mellitus were assessed using a structured questionnaire. Exploratory factor analysis and multivariate Tobit regression model were used to identify factors associated with knowledge, attitude, practice about diabetes mellitus.Results: Of 176 diabetic patients, patients’ knowledge was divided into two main groups: “Diabetes definition and management” (mean score = 57.7 ± 25.6) and “Targets for diabetic control” (mean score = 66.1 ± 30.4). Patients scored high points of attitudes toward diabetes severity and its complications (mean score = 95.8 ± 13.0); however, knowledge and practice scores were only moderate (mean score = 68.1 ± 16.8). There were only 8.5% of people having daily self-blood glucose monitoring. Advanced age, low educational level, rural area, and duration of diabetes less than 5 years were negative associated with knowledge, attitude, and practice regarding diabetes mellitus. This study also shows that frailty and co-morbidities/diabetic complications could impair patients’ knowledge.Conclusion: Older patients with diabetes had high levels of perceived severity attitudes on diabetes mellitus. However, the knowledge and practice levels were still inadequate. Pragmatic diabetic health literacy, counseling and education programs, as well as home-based treatments are viable options to improve health outcomes.Keywords: attitude, diabetes, elderly, knowledge, practice

This paper is motivated by the ongoing debate on university reform in Vietnam. In particular, there is a need to quantify the level of governmental support for public universities and examine whether or not such a support is adequate. To this end, the present paper estimates training costs per student in different disciplines within the Vietnamese public university education system in 2010. The various estimates of unit costs are based on the definitional approach which defines unit cost as the ratio of total costs over output. In measuring total costs, private costs incurred by university students (apart from formal tuition fees) are excluded. Further, the opportunity cost method employed emphasizes implicit costs such as imputed land rent. The total output is based on weighted student numbers. Unit costs are then estimated using a variety of primary (from survey) and secondary data sources. The results obtained suggest that the unit costs of public university education in Vietnam vary considerably between disciplines. The results also support the presence of economies of scale and scope in higher education and a negative relationship between unit costs and teaching quality proxies. The overall unit cost of public universities in Vietnam is very low in absolute terms when comparing with other countries. However, unit cost relative to GDP per capita in Vietnam is more comparable with those of neighboring countries. Nevertheless, the findings of the paper imply that more resources need to be allocated to the public university sector as part of an urgently needed university reform in Vietnam.

Deoxycholic acid (DCA), a secondary bile acid, is reportedly increased in the serum of patients with nonalcoholic steatohepatitis and animals with experimentally induced hepatocellular carcinoma (HCC), but its contribution to malignant behaviors of HCC has not been precisely clarified. This study aimed to examine the effect of DCA on hepatic stellate cells (HSCs), a major component of nonparenchymal cells in the liver, and its subsequent indirect effect on HCC cells. LX2 cells, a human HSC line, were treated with DCA in vitro. Then, HuH7 cells, a human hepatoma cell line, were incubated in conditioned media of DCA-treated LX2 to investigate the subsequent effect focusing on malignant behaviors. DCA resulted in cellular senescence in LX2 with the decreased cell proliferation via cell cycle arrest at G0/1 phase, together with the induction of senescence-associated secretory phenotype (SASP) factors. To investigate the influence of SASP factors secreted by HSCs in response to DCA, HCC cells were treated with conditioned media that promoted cell migration and invasion via induction of epithelial mesenchymal transition. These changes were attenuated in the presence of neutralizing antibody against IL8 or TGFβ. Pathological analysis of surgical specimens from HCC patients revealed that senescent HSCs were detected in the stroma surrounding HCC. Our data suggest an important role of HSC senescence caused by DCA for the malignant biological behaviors of HCC via induction of SASP factors, particularly IL8 and TGFβ.

Cuprous oxide nanoparticles (Cu2O) were prepared by a one-step reduction method at 65, 70 and 85oC temperature. The Cu2O nanoparticles were characterized by XRD, Raman, SEM and EDS techniques, respectively. The adsorption removal of red congo dye from aqueous solution by the as-prepared Cu2O nanoparticles was studied. Kinetics and isotherms studies suggested that the adsorption process followed pseudo-second-order and Freundlich models. The maximum adsorption capacity was estimated to be 82,6 mg/g, which was the highest reported value so far for red congo adsorption.