Saturation of Cao–Gonska operators Λ* and Λ+

We give characterizations by K-functionals and moduli of smoothness for discretized versions of Cao–Gonska operators having O(n ^?2) as their saturation order.We also identify the corresponding saturation class.     

Simultaneous quantification of propofol,ketamine and rocuronium in just 10 μL plasma using liquid chromatography coupled with quadrupole mass spectrometry and its pilot application to a pharmacokinetic study in rats

The combination of propofol, ketamine and rocuronium can be used for anesthesia of ventilated rats. However, reliable pharmacokinetic models of these drugs have yet to be developed in rats, and consequently optimal infusion strategies are also unknown. Development of pharmacokinetic models requires repeated measurements of drug concentrations. In small animals, samples must be tiny to avoid excessing blood extraction. We therefore developed a drug assay system using high‐performance liquid chromatography coupled with quadrupole mass spectrometry that simultaneously determines the concentration of all three drugs in just 10 μL rat plasma. We established a plasma extraction protocol, using acetonitrile as the precipitating reagent. Calibration curves were linear with R² = 0.99 for each drug. Mean recovery from plasma was 91–93% for propofol, 89–93% for ketamine and 90–92% for rocuronium. The assay proved to be accurate for propofol 4.1–8.3%, ketamine 1.9–7.8% and rocuronium ?3.6–4.7% relative error. The assay was also precise; the intra‐day precisions were propofol 2.0–4.0%, ketamine 2.7–2.9% and rocuronium 2.9–3.3% relative standard deviation. Finally, the method was successfully applied to measurement the three drugs in rat plasma samples. Mean plasma concentrations with standard deviations were propofol 2.0 μg/mL ±0.5%, ketamine 3.9 μg/mL ±1.0% and rocuronium 3.2 μg/mL ±0.8% during ventilation.     

Synthesis and Bioinformatic Characterization of New Schiff Bases with Possible Applicability in Brain Disorders

(1) Background: The research aims to find new treatments for neurodegenerative diseases, in particular, Alzheimer’s disease. (2) Methods: This article presents a bioinformatics and pathology study of new Schiff bases, (EZ)-N′-benzylidene-(2RS)-2-(6-chloro-9H-carbazol-2-yl)propanehydrazide derivatives, and aims to evaluate the drug-like, pharmacokinetic, pharmacodynamic and pharmacogenomic properties, as well as to predict the binding to therapeutic targets by applying bioinformatics, cheminformatics and computational pharmacological methods. (3) Results: We obtained these Schiff bases by condensing (2RS)-2-(6-chloro-9H-carbazol-2-yl)propanehydrazide with aromatic aldehydes, using the advantages of microwave irradiation. The newly synthesized compounds were characterized spectrally, using FT-IR and NMR spectroscopy, which confirmed their structure. Using bioinformatics tools, we noticed that all new compounds are drug-likeness features and may be proposed as potentially neuropsychiatric drugs (4) Conclusions: Using bioinformatics tools, we determined that the new compound 1e had a high potential to be used as a good candidate in neurodegenerative disorders treatment.     

Hybrid electro-optical nanosystem for neurons investigation

The scope of this paper is development of a new laboratory-on-a-chip (LOC) device for biomedical studies consisting of a microfluidic system coupled to microelectronic/optical transducers with nanometric features, commonly called biosensors. The proposed device is a hybrid system with sensing element on silicon (Si) chip and microfluidic system on polydimethylsiloxane (PDMS) substrates, taking into accounts their particular advantages. Different types of nanoelectrode arrays, positioned in the reactor, have been investigated as sensitive elements for electrical detection and the recording of neuron extracellular electric activity has been monitorized in parallel with whole-cell patch-clamp membrane current. Moreover, using an additional porosification process the sensing element became efficient for optical detection also. The preliminary test results demonstrate the functionality of the proposed design and also the fabrication technology, the devices bringing advantages in terms enhancement of sensitivity in both optoelectronic detection schemes.     

Constant sign and nodal solutions for a class of nonlinear Dirichlet problems

We consider a nonlinear Dirichlet problem with a Carathéodory reaction which has arbitrary growth from below. We show that the problem has at least three nontrivial smooth solutions, two of constant sign and the third nodal. In the semilinear case (i.e., p=2$p=2$), with the reaction f(z,.)$f(z,.)$ being C¹$C^1$ and with subcritical growth, we show that there is a second nodal solution, for a total of four nontrivial smooth solutions. Finally, when the reaction has concave terms and is subcritical and for the nonlinear problem (i.e., 1<p<∞$1<p<\infty$) we show that again we can have the existence of three nontrivial smooth solutions, two of constant sign and a third nodal.     

QSAR of caffeines by similarity cluster prediction

A novel QSAR approach based on correlation weighting and alignment over a hypermolecule that mimics the investigated correlational space was performed on a set of 40 caffeines downloaded from the PubChem database. The best models describing log P and LD50 values of this set of caffeine derivatives were validated against the external test set and in a new predictive model by using clusters of similarity.