ROS-Induced DNA-Damage and Autophagy in Oral Squamous Cell Carcinoma by Usnea barbata Oil Extract—An In Vitro Study

Oxidative stress is associated with aging, cancers, and numerous metabolic and chronic disorders, and phenolic compounds are well known for their health-promoting role due to their free-radical scavenging activity. These phytochemicals could also exhibit pro-oxidant effects. Due to its bioactive phenolic secondary metabolites, Usnea barbata (L.) Weber ex. F.H. Wigg (U. barbata) displays anticancer and antioxidant activities and has been used as a phytomedicine for thousands of years. The present work aims to analyze the properties of U. barbata extract in canola oil (UBO). The UBO cytotoxicity on oral squamous cell carcinoma (OSCC) CLS-354 cell line and blood cell cultures was explored through complex flow cytometry analyses regarding apoptosis, reactive oxygen species (ROS) levels, the enzymatic activity of caspase 3/7, cell cycle, nuclear shrinkage (NS), autophagy (A), and synthesis of deoxyribonucleic acid (DNA). All these studies were concomitantly performed on canola oil (CNO) to evidence the interaction of lichen metabolites with the constituents of this green solvent used for extraction. The obtained data evidenced that UBO inhibited CLS-354 oral cancer cell proliferation through ROS generation (316.67 × 10⁴), determining higher levels of nuclear shrinkage (40.12%), cell cycle arrest in G0/G1 (92.51%; G0 is the differentiation phase, while during G1 phase occurs preparation for cell division), DNA fragmentation (2.97%), and autophagy (62.98%) than in blood cells. At a substantially higher ROS level in blood cells (5250.00 × 10⁴), the processes that lead to cell death—NS (30.05%), cell cycle arrest in G0/G1 (86.30%), DNA fragmentation (0.72%), and autophagy (39.37%)—are considerably lower than in CLS-354 oral cancer cells. Our work reveals the ROS-mediated anticancer potential of UBO through DNA damage and autophagy. Moreover, the present study suggests that UBO pharmacological potential could result from the synergism between lichen secondary metabolites and canola oil phytoconstituents.     

Composite magnetic chitosan microspheres: In situ preparation and characterization

A method for preparing magnetic crosslinked chitosan microparticles was developed. The chitosan (CS) encapsulated magnetic particles were produced in alkaline conditions by in situ oxidation of the ferrous ions initially dispersed uniformly within the polysaccharide matrix. The polymer was then crosslinked using glutaraldehyde (GLA). The products were characterized regarding their size distribution and surface charge (by laser diffraction analysis, ζ-potential measurement, and conductometric titration), morphology (TEM), and magnetic properties (magnetic susceptibility analysis). The fact that the particles contain both magnetic iron oxide and chitosan was confirmed by FTIR and thermogravimetric analysis. The synthesis parameters were optimized for obtaining stable magnetic microparticles bearing surface amino groups that can subsequently be used for heavy metal ion complexation. The composite particles obtained by the optimum procedure had an average diameter of 40 μm and a saturation magnetization of 24 emu/g, corresponding to about 47% magnetic iron oxide content.     

Polyolefin/Lignosulfonate Blends, 9

Summary: In the present study, the compatibility, properties and degradability of polyolefin/lignin blends have been studied. Blends of three maleic anhydride grafted copolymers of ethylene‐propylene rubbers containing various content of functional groups with epoxy‐modified lignosulfonate have been investigated by microscopy, X‐ray diffraction, surface and mechanical indices determination, electron spin resonance, IR spectroscopy, differential scanning calorimetry and thermogravimetry. To assess the environmental degradation characteristics, the behavior of the blends during soil burial test has been investigated. The influence of the buried polymer blends on the physiological vegetative processes of the Vicia X Hybrida hort plant has been monitored.

Optical microscopy images of blend EP‐g‐MA 0.3/5 LER, undegraded (left) and degraded (right).     

Oxidation of Steel Samples in Air Under the Action of a Photodissociative Iodine Laser

Abstract

We report experimental data on the oxidation of steel samples in air by laser irradiation using pulses of different duration generated by a photodissociative iodine laser source. The results indicate an enhancement of the oxidation process under the action of laser radiation as compared with conventional oxidation techniques.     

Kinematics and workspace modeling of a new hybrid robot used in minimally invasive surgery

The geometric and kinematic models of a new surgical hybrid robot used for camera and active instruments positioning are presented in this paper. The robot workspace is computed and illustrated following the singularities analysis. The robot structure consists of two modules: the PARAMIS robot, and the new serial positioning module. The serial positioning module is used to obtain a mechanically fixed remote center of motion (RCM), enabling the structure to manipulate also active instruments. The new robot provides the necessary motion control to respect the particularities and restrictions of surgical applications. The detailed workspace analysis demonstrates the importance of the relative positioning between the robot and the patient. A constructive solution of the new serial module, the numerical results and conclusions from the performed simulations are described.     

Safety issues in the development of the experimental model for an innovative medical parallel robot used in brachytherapy

The paper presents a medical parallel robot (BR-1), designed for the minimally invasive, targeted, treatment of cancer through brachytherapy. The analysis of Jacobi matrices allows a complete study of the singularities while generating also a set of conditions which, implemented in the control system, enable the safe behaviour of the robot. Brachytherapy is an advanced form of cancer treatment involving the placement of small radioactive seeds directly inside the malignant tumour, allowing a very effective, local treatment of cancer. For this task an innovative parallel robotic system has been developed, having five degrees of freedom, constructed in two versions, BR-1R and BR-1T with a slight variation at the level of a passive joint. The two solutions revealed different accuracy distributions and by selecting the proper variant based on the tumour location, an increased universality degree for the BR-1 robot is obtained. The singularity-free workspace is determined using the assessment of singularities for both robot versions. The control system for both robot versions is simple, robust and intuitive allowing clinicians to have an accurate procedure, having real-time force monitoring during the needle insertion. The experimental data demonstrate that the robotic structure is a worthy candidate for robotic-assisted brachytherapy.     

The poisoning level of Pt/C catalysts used in PEM fuel cells by the hydrogen feed gas impurities: The bonding strength

Proton exchange membrane fuel cells (PEMFCs) most likely will use reformed fuel as the primary source for the anode feed despite it nearly always contains carbon monoxide or ammonia. In this paper, the microcalorimetry technique was employed to study and compare the poisoning effect of pollutants such as CO and NH₃ on three commercial carbon-supported platinum catalysts with high Pt loading, aimed to be used in PEMFCs applications. Microcalorimetric measurements were performed at 80 °C and the results were compared with those obtained from hydrogen adsorption in similar conditions. All the catalysts exhibited significantly higher differential heats of CO adsorption in comparison with NH₃ and hydrogen adsorption, indicating that carbon monoxide will be primarily adsorbed in case of co-adsorption, while ammonia and hydrogen will compete in the adsorption process on the same type of active sites. The irreversibly (chemically) amount of adsorbed molecules on Pt/C surfaces decreases in the order: CO >> NH₃ > H₂.