Some aggregation operators of neutrosophic Z-numbers and their multicriteria decision making method.

As the generalization of the classical fuzzy number, the concept of Z-number introduced by Zadeh indicates more ability to depict the human knowledge and judgments of both restraint and reliability as an order pair of fuzzy numbers. In indeterminacy and inconsistent environment, a neutrosophic set is described by the truth, falsity, and indeterminacy degrees, but they lack measures related to reliability. To describe the hybrid information of combining the truth, falsity and indeterminacy degrees with their corresponding reliability degrees, this paper first proposes the concept of a neutrosophic Z-number (NZN) set, which is a new framework of neutrosophic values combined with the neutrosophic measures of reliability, as the generalization of the Z-number and the neutrosophic set. Then, we define the operations of neutrosophic Z-numbers (NZNs) and a score function for ranking NZNs. Next, we present NZN weighted arithmetic averaging (NZNWAA) and NZN weighted geometric averaging (NZNWGA) operators to aggregate NZN information and investigate their properties. Regarding the NZNWAA and NZNWGA operators and the score function, a multicriteria decision making (MDM) approach is developed in the NZN environment. Finally, an illustrative example about the selection problem of business partners is given to demonstrate the applicability and effectiveness of the developed MDM approach in NZN setting.

Case Report: Pink Urine Syndrome Following Exposure to Propofol: A Rare, Impressive but Benign Complication.

Drug-induced changes in urine color induced by drugs may have clinical significance. Pink urine syndrome (PUS), which has been associated with urinary uric acid (UA) disorders, is most frequently reported in patients with morbid obesity undergoing gastric bypass surgery and/or from propofol anesthesia use in those who potentially have preexisting UA metabolism disorders. However, PUS has rarely occurred following exposure to propofol in non-obese patients, and literature on long-term follow-up after PUS is scarce. We report a case of PUS induced by propofol in a previously healthy non-obese woman after undergoing thoracoscopic wedge resection of pulmonary nodules under general anesthesia using propofol. The patient suddenly developed pink urine 4 h after surgery. A pink sediment rapidly precipitated at the bottom of the test tube following centrifugation of the urine. Amorphous, colorless UA-like crystals were identified under a polarizing microscope. The diagnosis of PUS was confirmed by examining the urinary UA concentration. The patient recovered and as followed-up for 1 month, during which she did not experience any urinary complications. To our knowledge, this is the first report to describe in detail a case of PUS caused by propofol in a non-obese patient with follow-up. PUS is usually benign and can resolve by rapidly on administering lactated Ringer's solution; however, the potential risk of urinary complications, particularly UA lithiasis, should be fully realized.

Graphene quantum dots in photodynamic therapy.

Graphene quantum dots (GQDs) have shown great promise in a variety of medical applications. Recently, it has been found that GQDs are also beneficial for photodynamic therapy (PDT). However, the findings of GQDs as PDT agents have been controversial in the literature. Herein, we investigate the photoactivity of single-atomic-layered GQDs by examining their ability to generate singlet oxygen (1O2) under irradiation and their effects on the photoactivity of photosensitizers. We demonstrate that the GQDs with lateral sizes of ∼5 or 20 nm are photo-inactive for they cannot generate 1O2 under irradiation of either a 660 nm laser (105 mW cm-2) or a halogen light. Moreover, the GQDs inhibit the photoactivity of two classical photosensitizers, namely, methylene blue and methylene violet. The stronger interaction between the GQDs and the photosensitizer results in greater inhibition of GQDs. Besides, the large-sized GQDs exhibit stronger inhibition than the small-sized GQDs. The inhibitory effect of the GQDs on the photoactivity of photosensitizers is consistent with their photo-cytotoxicity. These results indicate that the single-atomic-layered GQDs are not potential PDT agents, but they may be helpful for photosensitizers by delivering them into the cells. The discrepancy between the current work and the literature is probably associated with the GQDs used.

Separating graphene quantum dots by lateral size through gel column chromatography.

Graphene quantum dots (GQDs) prepared through photo-Fenton reaction of graphene oxide are separated via gel column chromatography. The as-separated GQDs were selectively introduced into the active layer of organic solar cells and achieved an enhancement of power conversion efficiency (PCE).

Flexible micro-supercapacitors assembled via chemically reduced graphene oxide films assisted by a laser printer.

Flexible micro-supercapacitors (MSCs) as power suppliers are important for portable and wearable electronic devices. Despite enormous efforts made, a simple, inexpensive high-throughput technique of graphene-based MSCs is still challenging. In this work, flexible MSCs are fabricated through commercial laser printing of the interdigital configuration of reduced graphene oxide-graphene oxide-reduced graphene oxide (rGO-GO-rGO) where the conductive rGO works as the electrode and the insulated GO serves as the separator. We demonstrate that the as-fabricated MSC devices show high-energy storage capacities, good cyclic stability and remarkable flexibility. The relationship between the geometric parameters (integration level and coverage fraction) and the capacitive performance of the MSCs is studied systematically to build better theoretical guidance for the design of future in-plane MSCs.

Analysis of a time-delayed mathematical model for tumour growth with an almost periodic supply of external nutrients.

In this paper, the existence, uniqueness and exponential stability of almost periodic solutions for a mathematical model of tumour growth are studied. The establishment of the model is based on the reaction-diffusion dynamics and mass conservation law and is considered with a delay in the cell proliferation process. Using a fixed-point theorem in cones, the existence and uniqueness of almost periodic solutions for different parameter values of the model is proved. Moreover, by the Gronwall inequality, sufficient conditions are established for the exponential stability of the unique almost periodic solution. Results are illustrated by computer simulations.

Graphene Quantum Dots Downregulate Multiple Multidrug-Resistant Genes via Interacting with Their C-Rich Promoters.

Multidrug resistance (MDR) is the major factor in the failure of many forms of chemotherapy, mostly due to the increased efflux of anticancer drugs that mediated by ATP-binding cassette (ABC) transporters. Therefore, inhibiting ABC transporters is one of effective methods of overcoming MDR. However, high enrichment of ABC transporters in cells and their broad substrate spectra made to circumvent MDR are almost insurmountable by a single specific ABC transporter inhibitor. Here, this study demonstrates that graphene quantum dots (GQDs) could downregulate the expressions of P-glycoprotein, multidrug resistance protein MRP1, and breast cancer resistance protein genes via interacting with C-rich regions of their promoters. This is the first example that a single reagent could suppress multiple MDR genes, suggesting that it will be possible to target multiple ABC transporters simultaneously with a single reagent. The inhibitory ability of the GQDs to these drug-resistant genes is validated further by reversing the doxorubicin resistance of MCF-7/ADR cells. Notably, GQDs have superb chemical and physical properties, unique structure, low toxicity, and high biocompatibility; hence, their capability of inhibiting multiple drug-resistant genes holds great potential in cancer therapy.

Composites of Graphene Quantum Dots and Reduced Graphene Oxide as Catalysts for Nitroarene Reduction.

Composites of graphene quantum dots (GQDs) and reduced graphene oxide (rGO) with unique three-dimensional (3D) structure are prepared and their catalytic activities for reduction of nitroarenes are explored. We demonstrate that the 3D GQDs/rGO composites are more active in nitroarene reduction than GQDs and rGO. Some of them are even more active than the Ag-embedded calcium alginate (Ag/CA) or Au-embedded calcium alginate (Au/CA) catalysts. Interestingly, their catalytic property is closely related to the ratio of GQDs to rGO in the 3D GQDs/rGO composites and GQDs-to-rGO mass ratio of 1/4 exhibits the highest catalytic activity. Raman spectra of the composites show that GQDs-to-rGO ratio is related to the number of the surface/edge defects, indicating that the sites of defect and edges are active sites. In addition, the catalytic performance of the 3D GQDs/rGO composites is also contributed by their unique 3D network structures that are beneficial for the reactant adsorption and product diffusion. Given also the long cycling duration and the easy recovery from the reaction system, 3D GQDs/rGO composites are potential applicable metal-free catalytic system for nitorarene reduction.

A Time-Delayed Mathematical Model for Tumor Growth with the Effect of a Periodic Therapy.

A time-delayed mathematical model for tumor growth with the effect of periodic therapy is studied. The establishment of the model is based on the reaction-diffusion dynamics and mass conservation law and is considered with a time delay in cell proliferation process. Sufficient conditions for the global stability of tumor free equilibrium are given. We also prove that if external concentration of nutrients is large the tumor will not disappear and the conditions under which there exist periodic solutions to the model are also determined. Results are illustrated by computer simulations.

Graphene quantum dots enhance anticancer activity of cisplatin via increasing its cellular and nuclear uptake.

Using assistant reagents to improve the pharmaceutical performance of cisplatin (CDDP) has been one of promising strategies. Owing to their extraordinary properties, graphene quantum dots (GQDs) have shown great potentials in biomedical applications. Here we demonstrate that the combination of GQDs with CDDP can effectively enhance the cytotoxicity, cell cycle arrest, and DNA fragmentation that induced by CDDP. We also found that the GQDs improved the interaction of CDDP with DNA. Combing these results with our previous finding that graphene oxide could enhance the permeability of the cells, we believe GQDs improve the pharmaceutical performance of CDDP via first increasing its cellular uptake through improving the cell permeability, and then reinforcing its interaction with DNA once it is inside cells. The remarkable enhancement to CDDP cellular uptake in CDDP resistant cells further specifies that GQDs can increase chemotherapy efficacy of anticancer drugs that are suboptimal due to the drug resistance.

Effect of Lateral Size of Graphene Quantum Dots on Their Properties and Application.

Well-defined graphene quantum dots (GQDs) are crucial for their biological applications and the construction of nanoscaled optoelectronic and electronic devices. However, as-synthesized GQDs reported in many works assume a very wide lateral size distribution; thus, their apparent properties cannot truthfully reflect intrinsic properties of the well-defined GQDs, and more importantly, the applications of GQDs will be affected and limited as well. In this work, we demonstrated that different sized GQDs with a narrow size distribution could be obtained via gel electrophoresis of the crude GQDs prepared through a photo-Fenton reaction of graphene oxide (GO). It is illustrated that the photoluminesce (PL) emissions of the well-defined GQDs originated mainly from the peripheral carboxylic groups and conjugated carbon backbone planes through fluorescence and UV-vis spectroscopies. More importantly, our findings challenge the notion that the excitation wavelength dependent PL property of the as-synthesized GQDs is the intrinsic property of the size-defined GQDs. Preliminary data at the cellular level indicated that the small sized GQDs exhibit weaker quenching DNA dye ability but higher toxicity to the cells compared to that of the as-synthesized GQDs. This discovery is essential to explore applications of the GQDs in pharmaceutics and to understand the origin of the optoelectronic properties of GQDs.

Development of a real-time crash risk prediction model incorporating the various crash mechanisms across different traffic states.

OBJECTIVE: This study aimed to identify the traffic flow variables contributing to crash risks under different traffic states and to develop a real-time crash risk model incorporating the varying crash mechanisms across different traffic states. METHODS: The crash, traffic, and geometric data were collected on the I-880N freeway in California in 2008 and 2009. This study considered 4 different traffic states in Wu's 4-phase traffic theory. They are free fluid traffic, bunched fluid traffic, bunched congested traffic, and standing congested traffic. Several different statistical methods were used to accomplish the research objective. RESULTS: The preliminary analysis showed that traffic states significantly affected crash likelihood, collision type, and injury severity. Nonlinear canonical correlation analysis (NLCCA) was conducted to identify the underlying phenomena that made certain traffic states more hazardous than others. The results suggested that different traffic states were associated with various collision types and injury severities. The matching of traffic flow characteristics and crash characteristics in NLCCA revealed how traffic states affected traffic safety. The logistic regression analyses showed that the factors contributing to crash risks were quite different across various traffic states. To incorporate the varying crash mechanisms across different traffic states, random parameters logistic regression was used to develop a real-time crash risk model. Bayesian inference based on Markov chain Monte Carlo simulations was used for model estimation. The parameters of traffic flow variables in the model were allowed to vary across different traffic states. Compared with the standard logistic regression model, the proposed model significantly improved the goodness-of-fit and predictive performance. CONCLUSIONS: These results can promote a better understanding of the relationship between traffic flow characteristics and crash risks, which is valuable knowledge in the pursuit of improving traffic safety on freeways through the use of dynamic safety management systems.

A highly fluorescent metallosalalen-based chiral cage for enantioselective recognition and sensing.

A highly fluorescent coordination cage [Zn8L4I8] has been constructed by treating enantiopure pyridyl-functionalized metallosalalen units (L) with zinc(II) iodide and characterized by a variety of techniques including microanalysis, thermogravimetric analysis (TGA), circular dichroism (CD) spectroscopy, and single-crystal and powder X-ray diffraction. Strong intermolecular π-π, CH⋅⋅⋅π, and CH⋅⋅⋅I interactions direct packing of the cage molecules to generate a 3D polycage network interconnected by pentahedral cages formed by adjacent pentamers. The cage has an amphiphilic helical cavity decorated with chiral NH functionalities capable of interactions with guest species such as saccharides. The fluorescence of the cage was greatly enhanced by five enantiomeric saccharides in solution, with enantioselectivity factors of 2.480-4.943, and by five enantiomeric amines in the solid state, with enantioselective fluorescence enhancement ratios of 1.30-3.60. This remarkable chiral sensing of both saccharides and amines with impressive enantioselectivity may result from the steric confinement of the cavity as well as its conformational rigidity. It holds great promise for the development of novel chiral cage materials for sensing applications.

Steady-state analysis of necrotic core formation for solid avascular tumors with time delays in regulatory apoptosis.

A mathematical model for the growth of solid avascular tumor with time delays in regulatory apoptosis is studied. The existence of stationary solutions and the mechanism of formation of necrotic cores in the growth of the tumors are studied. The results show that if the natural death rate of the tumor cell exceeds a fixed positive constant, then the dormant tumor is nonnecrotic; otherwise, the dormant tumor is necrotic.