Quantum materials made in microfluidics - critical review and perspective

Quantum materials exhibit excellent optical properties. They are applied for displays, sensors, detectors of radiation, as well as in bioimaging and ion detection. Quantum materials change their optical properties depending on their size. Therefore the synthesis of monodisperse quantum materials is a prime goal. Many years ago microfluidics reactors have been proven to be an effective tool to produce functional materials on the nanometer scale and to synthesize nanomaterials with controllable morphology and customized properties. Accordingly, this review focuses on recent progress and perspectives in the microfluidic fabrication of quantum materials. In this paper, examples are shown to demonstrate how quantum materials, including semiconductor nanocrystals, carbon quantum dots, metal nanoparticles (especially metal clusters), rare earth doped nanophosphors, and fluorescent oxide, are fabricated, and their quality and properties are controlled. The review aims to serve as an instruction for the scientific as well as an industry research group interested in the field of quantum materials synthesis and scale-up production

Separation of Ho3+ in Static Magnetic Field

Abstract The rare earths elements (REE) belong to the group of critical metals and they are achieving more and more interest due to their special properties. However, there occur some problems connected with their production. The most difficult phase is separation of REE. It includes a necessity to intensify currently applied processes and looking for new solutions. The present work introduces an idea to use differences in physical properties of the REE ions to get them separated. In the experimental part of the work some efforts were undertaken to analyse results presenting changes of holmium ions concentration under an influence of the magnetic field gradient. There was determined the gradient of magnetic field and concentration of Ho3+ ions depending on initial concentration of the solution and time. A simulation of changing the concentration of holmium ions in the solution under an influence of the magnetic field gradient was performed to compare the mathematical model with the obtained results

Micro droplet formation towards continuous nanoparticles synthesis

In this paper, micro droplets are generated in a microfluidic focusing contactor and then they move sequentially in a free-flowing mode (no wall contact). For this purpose, two different micro-flow glass devices (hydrophobic and hydrophilic) were used. During the study, the influence of the flow rate of the water phase and the oil phase on the droplet size and size distribution was investigated. Moreover, the influence of the oil phase viscosity on the droplet size was analyzed. It was found that the size and size distribution of the droplets can be controlled simply by the aqueous phase flow rate. Additionally, 2D simulations to determine the droplet size were performed and compared with the experiment.Marek Wojnicki, Magdalena Luty-Błocho, Volker Hessel, Edit Csapó, Ditta Ungor and Krzysztof Fitzne

Memantine reduces consumption of highly palatable food in a rat model of binge eating

Excessive consumption of highly palatable food has been linked to the development of eating disorders and obesity, and can be modeled in non-food-deprived rats by offering them a limited (2-h daily) access to an optional dietary fat. Since the glutamatergic system has recently emerged as a viable target for binge-eating medication development, we compared the effects of subchronic treatment with glutamatergic receptor antagonists to the effects of a reference appetite-suppressing agent sibutramine on highly palatable food (lard) and normal chow intake. In three separate experiments, the consumption of a standard laboratory chow and lard were measured during 12 days of medication treatment and for 6 days afterwards. Generalized estimating equations analysis demonstrated that sibutramine (7.5 mg/kg, PO) significantly decreased lard consumption, with a concurrent increase in chow consumption. Sibutramine effects disappeared after treatment discontinuation. The NMDA receptor antagonist memantine (5 mg/kg, IP) significantly decreased lard consumption and increased chow consumption, comparable to effects of sibutramine; however, memantine’s effects persisted after treatment discontinuation. The effects of the mGluR5 antagonist MTEP (7.5 mg/kg, IP) on food consumption were in the same direction as seen with memantine, but the observed differences were not significant. In an additional control experiment, sibutramine and memantine reduced unlimited (24 h) chow intake during the treatment phase. Present results provide evidence that glutamatergic neurotransmission might be involved in the regulation of excessive consumption of highly palatable foods, and suggest that NMDA receptor may be an attractive target for developing obesity and disordered eating pharmacotherapies

Hedonic and incentive signals for body weight control

Here we review the emerging neurobiological understanding of the role of the brain’s reward system in the regulation of body weight in health and in disease. Common obesity is characterized by the over-consumption of palatable/rewarding foods, reflecting an imbalance in the relative importance of hedonic versus homeostatic signals. The popular ‘incentive salience theory’ of food reward recognises not only a hedonic/pleasure component (‘liking’) but also an incentive motivation component (‘wanting’ or ‘reward-seeking’). Central to the neurobiology of the reward mechanism is the mesoaccumbal dopamine system that confers incentive motivation not only for natural rewards such as food but also by artificial rewards (eg. addictive drugs). Indeed, this mesoaccumbal dopamine system receives and integrates information about the incentive (rewarding) value of foods with information about metabolic status. Problematic over-eating likely reflects a changing balance in the control exerted by hypothalamic versus reward circuits and/or it could reflect an allostatic shift in the hedonic set point for food reward. Certainly, for obesity to prevail, metabolic satiety signals such as leptin and insulin fail to regain control of appetitive brain networks, including those involved in food reward. On the other hand, metabolic control could reflect increased signalling by the stomach-derived orexigenic hormone, ghrelin. We have shown that ghrelin activates the mesoaccumbal dopamine system and that central ghrelin signalling is required for reward from both chemical drugs (eg alcohol) and also from palatable food. Future therapies for problematic over-eating and obesity may include drugs that interfere with incentive motivation, such as ghrelin antagonists

Spectrophotometric Analysis of the Kinetic of Pd(II) Chloride Complex Ions Sorption Process from Diluted Aqua Solutions Using Commercially Available Activated Carbon

In this paper, results of adsorption kinetic studies of Pd(II) chloride complex ions on activated carbon Organosrob 10 CO are presented. Spectorphotometrical method was applied to investigate the process. Kinetic model was proposed, and fundamental thermodynamic parameters were determined. Proposed kinetic model describes well observed phenomenon in the studied range of concentration of Pd(II) chloride complex ions as well, as concentration of activated carbon

Eksperymentalne badania wypierania ropy metodą WAG z wykorzystaniem dwutlenku węgla

The article presents results of experimental studies of oil displacement efficiency by Water Alternating Gas (WAG) injection using carbon dioxide. WAG process was implemented as a tertiary recovery method, after waterflooding. The experiments were conducted on a long-core reservoir model at thermobaric conditions, which are characteristic for Polish carbonate reservoirs. Carbon dioxide injection was performed under miscible conditions (above minimum miscibility pressure). The results have practical importance because they confirm the suitability of conducting WAG process analysis on mentioned reservoir model and they present the WAG method effectiveness in specific reservoir conditions.W artykule przedstawiono wyniki badań eksperymentalnych nad skutecznością wypierania ropy, metodą naprzemiennego zatłaczania wody i gazu (z ang. Water Alternating Gas – WAG), z wykorzystaniem dwutlenku węgla. Proces WAG zastosowano jako metodę trzecią wspomagania wydobycia, po uprzednim procesie nawadniania. Badania przeprowadzono na fizycznym modelu złoża, zbudowanym z długich rdzeni wiertniczych, w warunkach termobarycznych charakterystycznych dla polskich złóż ropy w kolektorach węglanowych. Zatłaczanie dwutlenku węgla odbywało się w warunkach mieszających (powyżej minimalnego ciśnienia zmieszania). Uzyskane wyniki mają charakter praktyczny, gdyż potwierdzają stosowność prowadzenia analiz procesu WAG na wspomnianym modelu złoża oraz przedstawiają skuteczność metody w konkretnych warunkach złożowych

The Mechanism of Redox Reaction between Palladium(II) Complex Ions and Potassium Formate in Acidic Aqueous Solution

The kinetics studies of redox reaction between palladium(II) chloride complex ions and potassium formate in acidic aqueous solutions was investigated. It was shown, that the reduction reaction of Pd(II) is selective in respect to Pd(II) complex structure. The kinetic of the process was monitored spectrophotometrically. The influence of chloride ions concentration, Pd(II) initial concentration, reductant concentration, ionic strength as well as the temperature were investigated in respect to the process dynamics. Arrhenius equation parameters were determined and are equal to 65.8 kJ/mol, and A = 1.12×1011 s-1