Differential quadrature solution for the free vibration analysis of laminated conical shells with variable stiffness

The free vibration analysis of laminated conical shells with variable stiffness is presented using the method of differential quadrature (DQ). The stiffness coefficients are assumed to be functions of the circumferential coordinate that may be more close to the realistic applications. The first-order shear deformation shell theory is used to account for the effects of transverse shear deformations. In the DQ method, the governing equations and the corresponding boundary conditions are replaced by a system of simultaneously algebraic equations in terms of the function values of all the sampling points in the whole domain. These equations constitute a well-posed eigenvalue problem where the total number of equations is identical to that of unknowns and they can be solved readily. By vanishing the semivertex angle (α) of the conical shell, we can reduce the formulation of laminated conical shells to that of laminated cylindrical shells of which stiffness coefficients are the constants. Besides, the present formulation is also applicable to the analysis of annular plates by letting α=π/2. Illustrative examples are given to demonstrate the performance of the present DQ method for the analysis of various structures (annular plates, cylindrical shells and conical shells). The discrepancies between the analyses of laminated conical shells considering the constant stiffness and the variable stiffness are mainly concerned.     

Modified Packing Algorithm for Dynamic Energy-Saving in Cloud Computing Servers

Since the raising of the cloud computing, the applications of web service have been extended rapidly. However, the data centers of cloud computing also cause the problem of power consumption and the resources usually have not been used effectively. Decreasing the power consumption and enhancing resource utilization become main issues in cloud computing environment. In this paper, we propose a method, called MBFDP (modified best fit decreasing packing), to decrease power consumption and enhance resource utilization of cloud computing servers. From the results of experiments, the proposed solution can reduce power consumption effectively and enhance the utilization of resources of servers.     

Multi-Omics Reveal the Immunological Role and the Theragnostic Value of miR-216a/GDF15 Axis in Human Colon Adenocarcinoma

Colon adenocarcinoma (COAD) is the most common type of gastrointestinal cancer and is still the third leading cause of cancer-related mortality worldwide. Accurate screening tools for early diagnosis and prediction of prognosis and precision treatment strategies are urgently required to accommodate the unmet medical needs of COAD management. We herein aimed to explore the significance of the microRNA (miR)-216a/growth differentiation factor 15 (GDF15) axis in terms of clinical value, tumor immunity, and potential mechanisms in COAD by using multi-omic analysis. The gene expression levels of miR-216a and GDF15 showed an increase in the COAD group compared to those of the normal group. The expression of miR-216a presented a negative correlation with GDF15 in COAD tumor tissue. The use of an in vitro luciferase reporter assay and bioinformatic prediction revealed that miR-216a-3p acted toward translational inhibition on GDF15 by targeting its 3′untranslated region (UTR) site. High miR-216a expression was associated with decreased overall survival (OS), while the high expression of GDF15 was associated with increased OS. Enriched type 1 T-helper (Th1), enriched regulatory T (Treg), enriched eosinophils, and decreased nature killer T-cells (NKTs) in COAD tumor tissue may play counteracting factors on the tumor-regulatory effects of miR-216a and GDF15. In addition, high GDF15 expression had associations with suppressed immunoinhibitory genes and negative correlations with the infiltration of macrophages and endothelial cells. The enrichment analysis revealed that GDF15 and its co-expression network may be implicated in mitochondrial organization, apoptosis signaling, and endoplasmic reticulum (ER) stress response. The Genomics of Drug Sensitivity in Cancer (GDSC) and Cancer Therapeutics Response Portal (CTRP) analysis identified that Gemcitabine acted as a precision treatment for COAD when GDF15 expression was low. This study supports the miR-216a/GDF15 axis as a diagnostic/prognostic panel for COAD, identifies Th1, Treg, eosinophils, and NKTs as counteracting factors, indicates potential relationships underlying immunomodulation, mitochondrial organization, apoptotic signaling, and ER stress and unveil Gemcitabine as a potential drug for the development of treatment strategy when combined with targeting GDF15.     

Effects of magnetic fields on electricity generation in a photosynthetic ceramic microbial fuel cell

The aim of this study was to improve the efficiency of traditional proton exchange membranes by replacement using ceramic membranes with microalgae cathodes under various magnetic fields (MFs) of 100–300 mT in a ceramic microbial fuel cell (CMFC). The experimental results showed that the power generation can be enhanced by 61% when implementing a 200 mT MF. The application of a higher MF intensity, up to 200 mT, increased the electric charge generation yet decreased it with a higher MF value. Additionally, the MF had the ability to improve the power density of the CMFC, and a maximum power density of 35.9 mW m^?2 and maximum current density of 158.7 mA m^?2 were achieved with the 200 mT MF. Moreover, biocathode maintains a stable pH value that obtained more microalgae biomass by 200 mT MF stimulation. Further work will be focused on optimizing the appropriate MF intensity along with the capacity of carbon dioxide (CO₂) absorption by microalgae in CMFC.     

Ketogenic Diet Enhances the Cholesterol Accumulation in Liver and Augments the Severity of CCl4 and TAA-Induced Liver Fibrosis in Mice

Persistent chronic liver diseases increase the scar formation and extracellular matrix accumulation that further progress to liver fibrosis and cirrhosis. Nevertheless, there is no antifibrotic therapy to date. The ketogenic diet is composed of high fat, moderate to low-protein, and very low carbohydrate content. It is mainly used in epilepsy and Alzheimer’s disease. However, the effects of the ketogenic diet on liver fibrosis remains unknown. Through ketogenic diet consumption, β-hydroxybutyrate (bHB) and acetoacetate (AcAc) are two ketone bodies that are mainly produced in the liver. It is reported that bHB and AcAc treatment decreases cancer cell proliferation and promotes apoptosis. However, the influence of bHB and AcAc in hepatic stellate cell (HSC) activation and liver fibrosis are still unclear. Therefore, this study aimed to investigate the effect of the ketogenic diet and ketone bodies in affecting liver fibrosis progression. Our study revealed that feeding a high-fat ketogenic diet increased cholesterol accumulation in the liver, which further enhanced the carbon tetrachloride (CCl₄)- and thioacetamide (TAA)-induced liver fibrosis. In addition, more severe liver inflammation and the loss of hepatic antioxidant and detoxification ability were also found in ketogenic diet-fed fibrotic mouse groups. However, the treatment with ketone bodies (bHB and AcAc) did not suppress transforming growth factor-β (TGF-β)-induced HSC activation, platelet-derived growth factor (PDGF)-BB-triggered proliferation, and the severity of CCl₄-induced liver fibrosis in mice. In conclusion, our study demonstrated that feeding a high-fat ketogenic diet may trigger severe steatohepatitis and thereby promote liver fibrosis progression. Since a different ketogenic diet composition may exert different metabolic effects, more evidence is necessary to clarify the effects of a ketogenic diet on disease treatment.     

Mechanical and scratch behaviors of polyrotaxane-modified poly(methyl methacrylate)

The mechanical and scratch behaviors of polyrotaxane (PR) modified poly(methyl methacrylate) (PMMA) were investigated. PR is a necklace-like supramolecule with rings threaded onto a linear backbone chain that is capped by bulky end groups. Cyclodextrin (CD) serves as the ring structure and can be functionalized to induce specific interactions with the hosting polymer matrix. To systematically investigate the effect of CD functionalization on the mechanical properties of PMMA, PR with polycaprolactone (PCL) grafted chains on CD, and PR with methacrylate functional groups at the terminal of the PCL grafted chains on CD were chosen for this study. Tensile and compressive true stress–strain tests, ASTM scratch test, and coefficient of friction measurements were conducted to fundamentally understand how PR influences the mechanical and scratch behaviors of PMMA. Additionally, dielectric relaxation spectroscopy and dynamic mechanical analysis were conducted to explore how PR influences the relaxation dynamics of PMMA. The above findings suggest that the methacrylate functional group on PR induces favorable molecular interactions with PMMA matrix, leading to enhanced molecular cooperativity during deformation, which in turn improves tensile and compressive properties and achieves greatly improved scratch resistance.     

Copper oxide nanoparticle made by flame spray pyrolysis for photoelectrochemical water splitting - Part II. Photoelectrochemical study

A scalable method for hydrogen generation by splitting water via a photoelectrochemical cell was studied. Flame spray pyrolysis and spin coating processing methods were used for preparing copper oxide nanoparticles and copper oxide photocathodes. Copper oxide p-type semiconductor nanoparticles made by flame spray pyrolysis were spin coated on conducting ITO substrates and served as photocathodes for photoelectrochemical splitting of water. The film thickness was controlled by the concentration of the CuO suspension solution and numbers of layer deposited on the substrate. As sintering temperature increased to 600 °C, crystalline diameter increased from 28 nm (before sintering) to 110 nm and the bandgaps decreased from 1.68 eV to 1.44 eV. A 387 nm thickness CuO film with bandgap 1.44 eV was demonstrated to have 1.48% total conversion efficiency and 0.91% photon-to-hydrogen generation efficiency. The net photocurrent density (photocurrent - dark current) was measured to be 1.20 mA/cm² at applied voltage of −0.55 V vs. Ag/AgCl in 1 M KOH electrolyte with 1 sun (AM1.5G) illumination. Based on the Mott-Schottky plot, the carrier density was estimated to be 1.5 × 10²¹ cm⁻³ and the flatband potential to be 0.23 V vs. Ag/AgCl. Furthermore, the valence band edge and conduction band levels were found to lie at −5.00 eV and −3.56 eV respect to the vacuum respectively.     

Comparative study on MoS2 and WS2 for electrocatalytic water splitting

Replacing Pt by earth abundant catalysts is one of the most important tasks toward potential large-scale HER applications. Among many potential candidates, low cost and earth abundant transition metal dichalcogenides such as MoS₂ and WS₂ have been promising as good H₂ evolution electrocatalysts when they are engineered into the structures with active sites. In this work, we have performed systematic studies on the catalytic reactivity of both MoS₂ and WS₂ materials produced by one-step and scalable thermolysis from (NH₄)₂WS₄ and (NH₄)₂MoS₄ precursors respectively. Structural analysis shows that these materials prepared at a higher thermolysis temperature exhibit higher crystallinity. The H₂ evolution electrocatalysts efficiency for the MoS₂ prepared at a lower temperature is higher than those at higher temperatures, where amorphous MoS₂ or S₂²⁻${{\text{S}}_2}^{2-}$ species instead of crystalline MoS₂ is the main active site. By contrast, crystalline WS₂ prepared at high temperature is identified to be the key reaction site. Both catalysts display excellent efficiency and durability as an electrocatalyst operating in acidic electrolytes. This work provides fundamental insights for further design and preparation of emergent metal dichalcogenide catalysts, beneficial for the development in clean energy.     

Knowledge stickiness in the buyer-supplier knowledge transfer process: The moderating effects of learning capability and social embeddedness

Increased outsourcing yields less vertically-integrated firms, suppliers have to rely on different buyers and interdisciplinary teams for acquired and utilized knowledge to improve performance. However, knowledge transfer from buyers to suppliers is not always successful. Studies pertaining to the knowledge stickiness between firms in the knowledge transfer process, such as between buyers and suppliers, have been minimal. Furthermore, while knowledge transfer processes are essentially context-specific in terms of who participates and how they participate in the process, it is very important to put knowledge transfer into context. The results provide support for a curvilinear inverted-U shape relationship between knowledge stickiness and manufacturing capability. In addition, the influence of knowledge stickiness on manufacturing capability would be enhanced by the moderating variables of social embeddedness and learning capability. The finding further suggests that supplier manufacturing capabilities impact supplier commitment and supplier performance.     

Comprehensive evaluation criteria for English learning websites using expert validity surveys

This study aimed to develop a set of evaluation criteria for English learning websites. These criteria can assist English teachers/web designers in designing effective websites for their English courses and can also guide English learners in screening for appropriate and reliable websites to use in increasing their English ability. To fulfill our objective, we employed a three-phase research procedure: (a) establishing a preliminary set of criteria from a thorough review of the literature, (b) evaluating and refining the preliminary criteria by conducting interviews with in-service teachers and learners, and (c) validating and finalizing the criteria according to expert validity surveys. The established criteria have 46 items, classified into 6 categories (the number of items within the category) – general information (12), integrated English learning (13), listening (4), speaking (6), reading (5), and writing (6). The general information evaluates the authority, accuracy, and format of the learning websites. The integrated English learning evaluates the overall information relevant to English learning materials as well as the common features of the four language skills. The criteria for listening, speaking, reading, and writing, for example, examine the suitable intonation, skills of discourse, classification of reading articles by their attributes, and the proper use of discussion boards for students when practicing their writing skills. Based on qualitative and quantitative analysis of the interviews and expert validity surveys, we confirmed the effectiveness of the developed evaluation criteria with satisfactory indexes of inter-rater reliability, content validity, and factorial validity.