In the present work, lipase from Candida antarctica (CALB) was covalently immobilized on functionalized magnetic nanoparticles (MNPs) to catalyze biodiesel synthesis. Core-shell nanoparticles were ...synthesized by coating Fe3O4 core with silica shell (Fe3O4@SiO2). The nanoparticles functionalized with (3-glycidoxypropyl)trimethoxylsilane (GPTMS) were used as immobilization matrix. The protein binding efficiency on functionalized Fe3O4@SiO2 was calculated as 84%, preserving 97% of specific activity of the free enzyme. Physical and chemical properties of the nanoparticles and the immobilized lipase were characterized by TGA, XRD, SEM, IR, TEM and DLS. Higher thermal stability and methanol tolerance for immobilized derivatives were obtained compared to the free enzyme. The immobilized lipase was then used to produce biodiesel by transesterification of waste cooking oil with methanol. In an optimization study, the effect of oil to methanol ratio, tert-butanol and molecular sieve as water adsorbent on the yield of biodiesel production were considered. Optimum oil to methanol ratio at 1:3 was observed for immobilized CALB in biodiesel production. Molecular sieve had a great effect on yield, with almost 100% conversion. The immobilized preparation of CALB also presented a good reusability, keeping 100% of its initial activity after 6 cycles of the reaction.
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•CALB was covalently immobilized onto epoxy-functionalized magnetic nanoparticles.•Immobilization caused to remarkable improvement in thermal stability of CALB.•The immobilized lipase was studied for biodiesel production from waste cooking oil.•FAMEs production yield was greatly improved in the presence of molecular sieve.
Abstract Dissolved air flotation (DAF) is an effective method for separating suspended oil and solid particles from wastewater by utilizing small air bubbles. This study aims to investigate the ...impact of key factors, such as saturating pressure and water flow rate, on the separation of fine oil droplets from a water stream. The macroscopic flow patterns within the cell were analyzed using particle image velocimetry (PIV), while Digital Image Analysis (DIA) was employed to study microscopic phenomena, including oil droplet rising velocity and oil-bubble contact mechanisms. Our findings propose a safe operating window (specifically, water flow rate and saturation pressure) for the effective separation of oil droplets without any oil escaping into the clean water stream. It was found that the oil droplet rising velocity increases with the saturation pressure up to 200 kPa. However, a further increase in the pressure of the air saturating chamber leads to a decrease in oil droplet rising velocity. Additionally, we identified a peak in rising velocity at an oil droplet size of approximately 200 µm. Below this threshold, the rising velocity increases with droplet size, while for droplet sizes exceeding 200 µm, the rising velocity decreases with size. This behavior can be explained by the conflicting effects of droplet size increment according to the Stokes law for the rising velocity of oil droplets. As the droplet size increases, the average density of the bubbles/droplet aggregate rises, reducing the ∆ρ in the Stokes law and subsequently lowering the aggregate rising rate. However, as per the Stokes law, the oil droplet rising velocity increases proportionally to the square of its size.
The electrification of personal transportation holds great potential for lowering greenhouse gas emissions and reducing climate change. The promise of electric vehicles (EVs) to serve these goals has ...resulted in a broad range of supporting policies aimed at encouraging widespread EV adoption at both the state and federal levels in the United States and around the world. While the EV revolution and prospects of a world with ubiquitous EVs are impacting various industries and many aspects of daily life, strategic interactions between the power grid and EVs are crucial for a successful energy transition. However, managing the interplay between EVs and the power grid remains a challenge. Motivated by that tension, this paper surveys a variety of solutions, policies, and incentives that are focused on effectively managing EV charging behaviors. The paper’s objective is to explore these tools to ensure that EV owners have ultimate control over their personal vehicles while simultaneously allowing the power grid to mitigate adverse network impacts. Furthermore, this paper examines the role of charging infrastructure technology and its strategic placement in facilitating the seamless integration of EVs into the grid. Additionally, the paper highlights financial mechanisms associated with EV integration and discusses the consequences of these mechanisms.
Background
The pathogenesis of type 2 diabetes mellitus (T2DM) is associated with chronic oxidative stress and inflammation. It is well known that the expression of some miRNAs such as miRNA‐146a is ...upregulated in diabetic and hyperglycaemic patients, whereas circulating miRNA‐126 is reduced. Therefore, we aimed to determine the effects of astaxanthin (AST) supplementation on the circulating malondialdehyde (MDA) and interleukin 6 (IL‐6) levels, and the expression of miR‐146a and miR‐126 in patients with T2DM.
Methods
This randomised, double‐blind, placebo‐controlled clinical trial was conducted in 44 patients with T2DM randomly receiving 8 mg/d of oral AST (n = 22) or placebo (n = 22) for 8 weeks.
Results
We observed that AST supplementation could decrease plasma levels of MDA and IL‐6 (P < .05) and decrease the expression level of miR‐146a over time (fold change: −1/388) (P < .05).
Conclusion
AST supplementation might be beneficial for improving circulating MDA and IL‐6 and the down‐regulation of miR‐146a. However, future investigations are suggested to confirm these results.
Two studies were conducted to evaluate the effects of the follicular wave on ovarian function and fertility in dairy heifers and lactating cows. In study 1, the estrous cycle of the selected Holstein ...heifers was initially synchronized using two intra-muscular prostaglandin F2α (PGF2α) administrations 11 days apart. Heifers in group FFW (n = 14) received an intra-muscular 500 μg PGF2α administration on day 7 after detecting standing estrus, while Heifers in group SFW (n = 14) were administered PGF2α 13 days after detecting standing estrus. The pregnancy rates of FFW (n = 98) and SFW (n = 100) heifers were also determined 35–37 days after artificial insemination (AI). In Study 2, healthy Holstein lactating cows (n = 28) were randomly assigned to either the FFW (n = 14) or SFW (n = 14) groups. The estrous cycles of the cows were presynchronized using two intra-muscular administrations of PGF2α given 14 days apart. Then, the emergences of the follicular waves were induced using an Ovsynch protocol. The pregnancy rate of FFW (n = 99) versus SFW (n = 98) cows was also determined 35–37 days after AI. The ovulatory follicle and corpus luteum (CL) resulting from the ovulatory follicle of FFW were larger than those of the dominant follicle and the CL of SFW in dairy heifers and lactating cows. However, the pregnancy rate did not differ between the FFW and SFW groups in heifers and lactating cows 35–37 days after AI. In conclusion, although the characteristics of the ovulatory follicles in FFW versus SFW animals differed, the follicular wave in dairy heifers or lactating cows did not affect fertility.
New bioactive nanobiocomposite scaffolds based on silk fibroin nanofiber-porous starch are presented for potential bone tissue regeneration. The silk fibroin nanofibers were fabricated directly via ...wet electrospinning using methanol coagulation bath and then the chopped electrospun nanofibers were incorporated into the starch matrix, followed by particulate leaching and freeze-drying. To achieve bioactivity, the calcium phosphate was then deposited throughout the fabricated scaffolds via alternate soaking in saturated calcium and phosphate solutions at 37°C. The morphology, structure, swelling, and calcium phosphate forming ability of the scaffolds were evaluated and the results indicated that addition of silk fibroin nanofibers into the starch matrix reduced the mean pore size, porosity, and water uptake of the fabricated scaffolds. Moreover, the deposited calcium phosphate layer consists of both brushite and apatitic calcium phosphate. The highest amount of formed calcium phosphate is evident in the starch matrix and increasing the amount of silk fibroin nanofibers decreases calcium phosphate formation. Cell culture experiments with osteoblast-like cells (MG63) on the scaffolds coated with calcium phosphate demonstrated that incorporation of SF nanofibers into the starch hydrogel improves cell viability, proliferation, and attachment.
The stability of two rigid articulated pipes conveying fluid is considered. The velocity of fluid motion is harmonic. Parametric resonance for the second mode and 3:1 internal resonance in the ...presence of self-excited are considered. The method of multiple time scales has been applied for analysis. The effects of initial velocity
u
0
, ratio fluid mass per total fluid mass and pipes mass
γ
and flow frequency
β
on the frequency response for steady state and stability analyses are studied. Some comparative studies on the stability region of system are conducted with the results available in the open literature.
Plug-in Electric Vehicles (PEVs) play a pivotal role in transportation electrification. The flexible nature of PEVs' charging demand can be utilized for reducing charging cost as well as optimizing ...the operating cost of power and transportation networks. Utilizing charging flexibility of geographically spread PEVs requires design and implementation of efficient optimization algorithms. There is a synergy between electro mobility (e-Mobility) infrastructures (including charging stations) and PEVs. In this paper, we introduce a holistic framework to model interdependent nature of power systems and electrified transportation networks, enhance the operational performance of these systems as a network-of-networks, and explain the required information exchange via coupling agents (e.g., PEVs and charging stations). We develop a holistic framework that enables distributed coordination of interdependent networks through the IoT lens. To this end, we propose to use a fully distributed consensus+innovations approach. This iterative algorithm achieves a distributed solution of the decision making for each agent through local computations and limited communication with other neighboring agents that are influential in that specific decision. For instance, the optimal routing decision of a PEV involves a different set of agents as compared with the optimal charging strategy of the same PEV. The exogenous information from an external network/agent can affect internal operation of the other agents. For instance, having some information about traffic congestion at the transportation networks changes the decision of PEVs to charge their battery at another location. Our approach constitutes solving an iterative problem, which utilizes communication at the smart city layer, as a network of infrastructures, including power grid and electrified transportation network, that enables fully distributed coordination of agents. Fully distributed decision making enables scalability of the solution and plug-and-play capability, as well as increasing the information privacy of PEVs by only requiring limited local information exchange with neighboring agents. We investigate a detailed application of our framework for interdependent power systems and electrified transportation networks. To this end, we first identify the functionalities, constraints, objectives, and decision variables of each network. Then, we investigate the interdependent interactions among these networks and their corresponding agents.
Strong near-infrared (NIR) absorption of reduced graphene oxide (rGO) make this material a candidate for photothermal therapy. The use of rGO has been limited by low stability in aqueous media due to ...the lack of surface hydrophilic groups. We report synthesis of a novel form of reduced graphene-arginine (rGO-Arg) as a nanoprobe. Introduction of Arg to the surface of rGO not only increases the stability in aqueous solutions but also increases cancer cell uptake. Atomic force microscopy (AFM) and transmission electron microscopy (TEM) images are recorded to characterize the morphology of rGO-Arg. Fourier transform infrared (FTIR), X-ray photoelectron spectra (XPS), Raman, and UV–vis spectroscopy are utilized to analyze the physiochemical properties of rGO-Arg. Interaction of rGO-Arg with 808 nm laser light has been evaluated by measuring the absorption cross section in response to periodically modulated intensity to minimize artifacts arising from lateral thermal diffusion with a material scattering matched to a low scattering optical standard. Cell toxicity and cellular uptake by MD-MB-231 cell lines provide supporting data for the potential application of rGO-Arg for photothermal therapy. Absorption cross-section results suggest rGO-Arg is an excellent NIR absorber that is 3.2 times stronger in comparison to GO.
•We specify abundance, size and color distribution of plastic debris.•We study metal contents of microplastics (MPs) in Persian Gulf area for first time.•The majority of plastic items (79.3%) were ...smaller than 5 mm (defined size of MPs).•There was significant difference between plastic number at different sampling times.
This study reports number, size and color distribution, and metal contents of microplastics as well as adherent sediments along the Persian Gulf. Samples were collected from 9 stations in summer 2015 with a sampling time interval of 10 days. Plastic size of 2–5 mm, and ≤0.25 mm with 45 and 33% and white and colorless plastics with 62 and 33% had the highest abundance considering number per m2, respectively. In general, the majority of collected plastics (79%) were smaller than 5 mm (defined size for microplastics). The mean Al, Fe, Mn, Cd, Cr, Ni, Pb, Cu contents of plastic fragments were 115, 531, 32.2, 0.035, 0.915, 2.03, 4.59, and 3.6 μg g−1, respectively while the mean Al, Fe, Mn, Cd, Cr, Ni, Pb, Cu contents of sediments were 186, 3050, 127, 0.81, 5.01, 14.5, 48.6 and 5.43 μg g−1 respectively. There were significant differences between the abundance of plastic items as well as the all examined metal concentrations of microplastics and sediments at different sampling times. As there is no regular cleanup program in the studied areas, significant differences between plastic items number at different sampling times (with higher plastic items number at the first day of sampling) showed that a large number of plastic items may enter from beaches to the sea and become available to marine organisms.
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