Magnetic nanoparticles (MNPs) with surface coatings designed for water treatment, in particular for targeted removal of contaminants from produced water in oil fields, have drawn considerable attention due to their environmental merit. The goal of this study was to develop an efficient method of removing very stable, micron-scale oil droplets dispersed in oilfield produced water. We synthesized MNPs in the laboratory with a prescribed surface coating. The MNPs were superparamagnetic magnetite, and the hydrodynamic size of amine functionalized MNPs ranges from 21 to 255 nm with an average size of 66 nm. The initial oil content of 0.25 wt.% was reduced by as much as 99.9% in separated water. The electrostatic attraction between negatively charged oil-in-water emulsions and positively charged MNPs controls, the attachment of MNPs to the droplet surface, and the subsequent aggregation of the electrically neutral oil droplets with attached MNPs (MNPs-oils) play a critical role in accelerated and efficient magnetic separation. The total magnetic separation time was dramatically reduced to as short as 1 s after MNPs, and oil droplets were mixed, in contrast with the case of free, individual MNPs with which separation took about 36∼72 h, depending on the MNP concentrations. Model calculations of magnetic separation velocity, accounting for the MNP magnetization and viscous drag, show that the total magnetic separation time will be approximately 5 min or less, when the size of the MNPs-oils is greater than 360 nm, which can be used as an optimum operating condition.
Modeling the rate of penetration of the drill bit is essential for optimizing drilling operations. This paper evaluates two different approaches to ROP prediction: physics-based and data-driven modeling approach. Three physics-based models or traditional models have been compared to data-driven models. Data-driven models are built using machine learning algorithms, using surface measured input features - weight-on-bit, RPM, and flow rate – to predict ROP. Both models are used to predict ROP; models are compared with each other based on accuracy and goodness of fit (R2). Based on the results from these simulations, it was concluded that data-driven models are more accurate and provide a better fit than traditional models. Data-driven models performed better with a mean error of 12% and improve the R2 of ROP prediction from 0.12 to 0.84. The authors have formulated a method to calculate the uncertainty (confidence interval) of ROP predictions, which can be useful in engineering based drilling decisions.
Amyloid-beta peptide (A beta) fibrillation is pathologically associated with Alzheimer's disease (AD), and this has resulted in the development of an A beta inhibitor which is essential for the treatment of AD. However, the design of potent agents which can target upstream secretases, inhibit A beta toxicity and aggregation, as well as cross the blood-brain barrier remains challenging. In, this research carbon dots for AD treatment were investigated in vitro using experimental and computational methods for the first time. The results presented here demonstrate a novel strategy for the discovery of novel antiamyloidogenic agents for AD treatments.
Size and pump-fluence dependent ultrafast carrier dynamics of CdSeTe QDs are investigated using femtosecond pump-probe techniques operating at two different repetition rates: 1 kHz (low-repetition rate), and 76 MHz (high-repetition rate). With a low-repetition rate laser and 3.1 eV excitation photon energy, multiple exciton generation (MEG) is observed and the optical responses of alloyed QDs clearly show three components: a fast decay ascribed to carrier recombination, an intermediate component associated with MEG decay, and a slow decay associated with radiative Auger recombination. With a high-repetition rate laser and excitation photon energy resonant with band-edge energy, obvious coherent phonon oscillations are observed in 4 nm CdSeTe QDs due to impulsive stimulated Raman scattering. Open-aperture Z-scan measurement is used to clarify the size and pump-fluence dependence of optical nonlinearity under femtosecond laser excitation. With increasing laser power, an evolution from saturable absorption to reverse saturable absorption in CdSeTe QDs is observed. The transition process is analyzed using a phenomenological model based on nonlinear absorption coefficient and saturation intensity. These results indicate that CdSeTe QDs in a glass matrix are a class of materials for potential application in all-optical switching devices.
Catalytic reduction of nitrate in ion exchange (IX) waste brine for reuse is a promising option for reducing IX costs and environmental impacts. A recycling trickle bed reactor (TBR) was designed and optimized using 0.5 percent byweight (wt%) palladium–0.05 wt% indium catalysts supported on US mesh size 12 × 14 or 12 × 30 activated carbon particles. Various liquid superficial velocities (Ur) and hydrogen gas superficial velocities (Ug-H2) were evaluated to assess performance in different flow regimes; catalyst activity increased with Ug-H2 at all Ur for both catalysts and was greatest for the 12 × 30 catalyst at thelowest Ur (8.9 m/h). The 12 × 30 catalyst demonstrated up to 100% higher catalytic activity and 280% higher mass transfer rate compared with the 12 × 14 catalyst. Optimal TBR performance was achieved with both catalysts in thetrickle flow regime. The results indicate that the TBR is a promising step forward, and continued improvements are possible to overcome remaining mass transfer limitations.
Palladium (Pd)-based catalysts hold promise as an alternative water treatment technology for nitrate (NO3–), but practical application requires a flow-through reactor that efficiently delivers hydrogen (H2) from gas to water. A trickle bed reactor (TBR) packed with a 0.1 percent by weight (wt%) Pd–0.01 wt% In/γ-Al2O3 (indium and porous aluminum oxide) catalyst was evaluated to address this challenge. Catalytic activity generally increased with H2 superficial velocity (0.65–29.6 m/h) and liquid (deionized water) superficial velocities from 14.8 to 26.6 m/h before decreasing at 38.5 m/h. This decrease corresponded to a change in flow regime and suggests that optimal TBR performance occurs at the transition from pulse to bubble flow. An optimal TBR activity of 19.5 ± 1.3 mg NO3–/min-g Pd was obtained; this is only ~18% of the batch reactor activity as a result of H2 mass transfer limitations, but three to 15 times greater than activities obtained with previous flow-through reactors. Catalyst deactivation occurred in the TBR after 41 days of operation, motivating the need for improved fouling mitigation strategies.
Immune checkpoint therapy has become the first widely adopted immunotherapy for patients with late stage malignant melanoma, with potential for a wide range of cancers. While some patients can experience long term disease remission, this is limited only to a subset of patients and tumor types. The path forward to expand this therapy to more patients and tumor types is currently thought to be combinatorial treatments, the combination of immunotherapy with other treatments. In this review, the combinatorial approach of immune checkpoint therapy combined with nanoparticle-assisted localized hyperthermia is discussed, starting with an overview of the different nanoparticle hyperthermia approaches in development, an overview of the state of immune checkpoint therapy, recent reports of immune checkpoint therapy and nanoparticle-assisted hyperthermia in a combinatorial approach, and finally a discussion of future research topics and areas to be explored in this new combinatorial approach to cancer treatment.
Laser-mediated photothermal ablation of cancer cells aided by photothermal agents is a promising strategy for localized, externally controlled cancer treatment. We report the synthesis, characterization, and in vitro evaluation of conductive polymeric nanoparticles (CPNPs) of poly(diethyl-4,4'-[2,5-bis(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)-1,4-phenyle ne] bis(oxy)dibutanoate) (P1) and poly(3,4-ethylenedioxythiophene) (PEDOT) stabilized with 4-dodecylbenzenesulfonic acid and poly(4-styrenesulfonic acid-co-maleic acid) as photothermal ablation agents. The nanoparticles were prepared by oxidative-emulsion polymerization, yielding stable aqueous suspensions of spherical particles of <100 nm diameter as determined by dynamic light scattering and electron microscopy. Both types of nanoparticles show strong absorption of light in the near infrared region, with absorption peaks at 780 nm for P1 and 750 nm for PEDOT, as well as high photothermal conversion efficiencies ( 50%), that is higher than commercially available gold-based photothermal ablation agents. The nanoparticles show significant photostability as determined by their ability to achieve consistent temperatures and to maintain their morphology upon repeated cycles of laser irradiation. In vitro studies in MDA-MB-231 breast cancer cells demonstrate the cytocompatibility of the CPNPs and their ability to mediate complete cancer cell ablation upon irradiation with an 808-nm laser, thereby establishing the potential of these systems as agents for laser-induced photothermal therapy.