Oxidative Effects during Irreversible Electroporation of Melanoma Cells—In Vitro Study

Irreversible electroporation (IRE) is today used as an alternative to surgery for the excision of cancer lesions. This study aimed to investigate the oxidative and cytotoxic effects the cells undergo during irreversible electroporation using IRE protocols. To do so, we used IRE-inducing pulsed electric fields (PEFs) (eight pulses of 0.1 ms duration and 2–4 kV/cm intensity) and compared their effects to those of PEFs of intensities below the electroporation threshold (eight pulses, 0.1 ms, 0.2–0.4 kV/cm) and the PEFs involving elongated pulses (eight pulses, 10 ms, 0.2–0.4 kV/cm). Next, to follow the morphology of the melanoma cell membranes after treatment with the PEFs, we analyzed the permeability and integrity of their membranes and analyzed the radical oxygen species (ROS) bursts and the membrane lipids’ oxidation. Our data showed that IRE-induced high cytotoxic effect is associated both with irreversible cell membrane disruption and ROS-associated oxidation, which is occurrent also in the low electric field range. It was shown that the viability of melanoma cells characterized by similar ROS content and lipid membrane oxidation after PEF treatment depends on the integrity of the membrane system. Namely, when the effects of the PEF on the membrane are reversible, aside from the high level of ROS and membrane oxidation, the cell does not undergo cell death.     

Anisotropic crystal growth in aerosil/polymethylmethacrylate systems dispersed in dimethacrylate monomers

Complex organized crystals were shown to grow within the settled phase composed of aggregated aerosil/polymethylmethacrylate or aerosil/poly(cetyl vinyl ether-maleic anhydride) resulting from the supply of the corresponding homopolymer or the alternated copolymer to the aerosil initially dispersed in a mixture of dimethacrylate monomers. The basic suspending phase was realized by mixing 1,3-butanediol dimethacrylate and bisphenol A dimethacrylate. The crystal nucleation and growth were both extremely slow processes that developed over months. Small and large crystals were realized usually displaying the shape of hexagonal platelets. The dose of polymer initially supplied to the system exerted a structuring role in the crystalline organization. DCS determinations showed the enthalpy of fusion to depend on the polymer dose and molecular weight. AFM showed the basal and lateral phases to grow with developing steps of two different thicknesses. The monomer ordering was evidenced by the fact that the polymerization shrinkage only affected the sequence of monomers lying parallel to the basal phases, the polymerization of monomers along the perpendicular axis being prevented from any shrinkage.     

Providing deterministic packet delays and packet losses in multimedia wireless networks

‘Anytime, anywhere’ communication, information access and processing are much cherished in modern societies because of their ability to bring flexibility, freedom and increased efficiency to individuals and organizations. Wireless communications, by providing ubiquitous and tetherless network connectivity to mobile users, are therefore bound to play a major role in the advancement of our society. Although initial proposals and implementations of wireless communications are generally focused on near‐term voice and electronic messaging applications, it is recognized that future wireless communications will have to evolve towards supporting a wider range of applications, including voice, video, data, images and connections to wired networks. This implies that future wireless networks must provide quality‐of‐service (QoS) guarantees to various multimedia applications in a wireless environment. Typical traffic in multimedia applications can be classified as either Constant‐Bit‐Rate (CBR) traffic or Variable‐Bit‐Rate (VBR) traffic. In particular, scheduling the transmission of VBR multimedia traffic streams in a wireless environment is very challenging and is still an open problem. In general, there are two ways to guarantee the QoS of VBR multimedia streams, either deterministically or statistically. In particular, most connection admission control (CAC) algorithms and medium access control (MAC) protocols that have been proposed for multimedia wireless networks only provide statistical, or soft, QoS guarantees. In this paper, we consider deterministic QoS guarantees in multimedia wireless networks. We propose a method for constructing a packet‐dropping mechanism that is based on a mathematical framework that determines how many packets can be dropped while the required QoS can still be preserved. This is achieved by employing: (1) An accurate traffic characterization of the VBR multimedia traffic streams; (2) A traffic regulator that can provide bounded packet loss and (3) A traffic scheduler that can provide bounded packet delay. The combination of traffic characterization, regulation and scheduling can provide bounded loss and delay deterministically. This is a distinction from traditional deterministic QoS schemes in which a 0% packet loss are always assumed with deterministically bounding the delay. We performed a set of performance evaluation experiments. The results will demonstrate that our proposed QoS guarantee schemes can significantly support more connections than a system, which does not allow any loss, at the same required QoS. Moreover, from our evaluation experiments, we found that the proposed algorithms are able to out‐perform scheduling algorithms adopted in state‐of‐the‐art wireless MAC protocols, for example Mobile Access Scheme Based on Contention and Reservation for ATM (MASCARA) when the worst‐case traffic is being considered. Copyright © 2002 John Wiley & Sons, Ltd.     

Spectrofluorimetric Approach for Quantification of Cyclizine in the Presence of its Toxic Impurities in Human Plasma; in silico Study and ADMET Calculations

Journal of Fluorescence - Cyclizine (CYZ); an antiemetic compound; is widely misused for its euphoric or hallucinatory effects, either by oral or intravenous routes. The concomitant abuse of CYZ...     

Correction to: On Formal Modeling and Validation of Wireless Sensor Network Protocols

Wireless Personal Communications -     

In Vitro Study of Calcium Microsecond Electroporation of Prostate Adenocarcinoma Cells

Electroporation, applied as a non-thermal ablation method has proven to be effective for focal prostate treatment. In this study, we performed pre-clinical research, which aims at exploring the specific impact of this so-called calcium electroporation on prostate cancer. First, in an in-vitro study of DU 145 cell lines, microsecond electroporation (μsEP) parameters were optimized. We determined hence the voltage that provides both high permeability and viability of these prostate cancer cells. Subsequently, we compared the effect of μsEP on cells’ viability with and without calcium administration. For high-voltage pulses, the cell death’s mechanism was evaluated using flow-cytometry and confocal laser microscopy. For lower-voltage pulses, the influence of electroporation on prostate cancer cell mobility was studied using scratch assays. Additionally, we applied calcium-binding fluorescence dye (Fluo-8) to observe the calcium uptake dynamic with the fluorescence microscopy. Moreover, the molecular dynamics simulation visualized the process of calcium ions inflow during μsEP. According to our results calcium electroporation significantly decreases the cells viability by promoting apoptosis. Furthermore, our data shows that the application of pulsed electric fields disassembles the actin cytoskeleton and influences the prostate cancer cells’ mobility.     

Spectroelectrochemical and Chemical Evidence of Surface Passivation at Zinc Ferrite (ZnFe2O4) Photoanodes for Solar Water Oxidation

Recent advances in low-cost manufacturing as well as in bulk/interface engineering have positioned zinc ferrite (ZnFe₂O₄, ZFO) in the spotlight as a candidate material for solar water oxidation. However, the severe recombination at the reactive interface remains as the main source of the poor onset potential. Although catalytic overlayers have shown to override, at least partially, the surface recombination, passivating-only coatings are barely explored despite holding the key to specifically suppress the recombination. Here, a sub-nanometer Al₂O₃ layer is conformally deposited onto nanostructured ZFO, leading to a 100 mV shift in the onset potential reaching 0.80 V versus reversible hydrogen electrode (RHE) and a fourfold photocurrent increase at 1.0 V versus RHE. The passivation-only effect of Al₂O₃ is confirmed by the slowing down of the surface recombination detected by intensity-modulated photocurrent spectroscopy and by the transient photovoltage and photoluminescence experiments. Further characterization of the chemical states at the reactive interface reveals that the partial filling of the surface oxygen vacancies and the formation of a Zn²⁺–Al³⁺ Lewis adduct are potentially involved in the surface passivation. This study not only demonstrates that Al₂O₃ improves ZFO's onset potential but also sheds light on the up until now unknown surface passivation mechanism.     

A disposable immunosensor for detection of 17beta-estradiol in non-extracted bovine serum

This paper reports the assembly of a disposable immunosensor based on the direct competitive enzyme-linked immunosorbent assay (ELISA), for simple and fast measurement of 17β-estradiol (17β-E₂) in bovine serum, using screen-printed electrodes (SPEs) and a Palm-Sens portable electrochemical detector. The immunosensor strip was assembled immobilising, by passive adsorption, anti-rabbit IgG onto the surface of the working SPE electrode. After the interaction between anti-rabbit IgG and rabbit anti-17β-E₂ polyclonal antibodies (PAb), the competition was performed using 17β-estradiol-alkaline phosphatase conjugate (17β-E₂-AP) synthesised in our laboratory. The enzymatic substrate used for signal generation was 1-naphthylphosphate and its conversion to an electroactive product (1-naphthol) was measured using differential pulse voltammetry (DPV). To develop a prototype for field measurements, the entire competitive protocol has been optimised directly in a blank non-extracted bovine serum.According to the new EU criteria established by the Commission Decision 2002/657/EC for qualitative and quantitative screening methods, the detection capability (CCβ), was determined. The CCβ value resulted below the action limit (40 pg mL⁻¹) fixed for 17β-E_2.Spiked and real samples were analysed using the electrochemical immunostrips obtaining precision values (relative standard deviation, R.S.D.%) ranging from 8.6 to 17.0% and a recovery (R%) from 88.2 to 120.0%.Results obtained on real samples were confirmed by liquid chromatography coupled on-line with tandem mass spectrometry (LC-MS/MS) using an atmospheric pressure chemical ionisation (APCI) source and a heated nebulizer (HN) interface; this is the method currently used to confirm illegal hormone administration for regulatory purposes. The disposable immunosensor appears suitable as a screening tool for field analysis of bovine serum estradiol.     

A pairwise almost disjoint subspace of kN of maximal dimension

We show that if k is an infinite field, then there exists a subspace $W?k^{\mathbb{N}}$ of dimension $|k{|}^{{\mathrm{?}}_0}$, such that no nonzero member of W has infinitely many zeros. This generalizes a result from a paper by Bergman and Nahlus, and partly answers another question from the same paper.