Comparison of Activation Methods for 3D-Printed Electrodes for Microbial Electrochemical Technologies

Three-dimensional printing could provide flexibility in the design of a new generation of electrodes to be used in microbial electrochemical technologies (MET). In this work, we demonstrate the feasibility of using polylactic acid (PLA)/graphene—a common 3D-printing material—to build custom bioelectrodes. We also show that a suitable activation procedure is crucial to achieve an acceptable electrochemical performance (plain PLA/graphene bioanodes produce negligible amounts of current). Activation with acetone and dimethylformamide resulted in current densities similar to those typically observed in bioanodes built with more conventional materials (about 5A m−2). In addition, the electrodes thus activated favored the proliferation of electroactive bacteria.

Activated Bio-Carbons Prepared from the Residue of Supercritical Extraction of Raw Plants and Their Application for Removal of Nitrogen Dioxide and Hydrogen Sulfide from the Gas Phase

The waste materials left after supercritical extraction of hop cones and marigold flowers were tested as precursors of activated bio-carbons. Adsorbents were produced by means of the physical (also called thermal) activation method using CO2 as the gasifying agent. All the activated bio-carbons were tested for the removal of NO2 and H2S from the gas phase under dry and wet conditions. The effects of the type of precursor and the activation procedure on the porous structure development, the acid-base properties of the surface, as well as the sorption capacities of the materials produced were also checked. The final products were bio-carbons of medium developed surface area with a basic surface nature, characterized by their high effectiveness in removal of gas pollutants of acidic character, especially nitrogen dioxide (sorption capacities in the range from 12.5 to 102.6 mg/g). It was proved that the toxic gas removal efficiency depends considerably on the sorption conditions and the activation procedure. All materials showed greater effectiveness in gas removal when the process of adsorption was carried out in the presence of steam.

LoRaWAN Security

The LoRaWAN security design adheres to state-of-the-art principles: use of standard, well-vetted algorithms, and end-to-end security. The fundamental properties supported in LoRaWAN security are mutual end-point authentication, data origin authentication, integrity and replay protection, and confidentiality. The use of symmetric cryptography and prior secret key sharing between a device and a server enables an extremely power efficient and network efficient activation procedure.

Sintesis Nitroselulosa Dari Serat Rami (Boechmerianivea) Menggunakan Trietilamin

Nitrocellulose is cellulose that is titrated into an ester polymer which can be used as a major component in several types of ammunition and explosives and other materials. Hemp (Boehmeria nivea) is a type of fiber plant that is rich in cellulose and thrives in Indonesia. Until now, the need for nitrocellulose in Indonesia is still imported, even though there is a lot of potential for cellulose that can be exploited, one of which is by synthesizing nitrocellulose from the hemp plant. One of the many uses of nitrocellulose derivatives, one of which is propellant. The propellant is the fuel or power source of a rocket engine. Nitrocellulose that can be used for propellants is nitrocellulose with levels between 11-13.3% nitrogen. This study aims to produce nitrocellulose in levels that meet the standards for making propellants. The study was carried out with a cellulose activation procedure using 20% ​​sodium hydroxide and 1 ml of triethylamine per gram of cellulose. Cellulose nitration was carried out using sulfuric acid and nitric acid with the composition of A (1: 1), B (2: 1) and C (3: 1) which were refluxed for 3 hours. Nitrogen determination was carried out using the Kjeldahl method. The results showed that from 3 samples A, B, and C, nitrogen levels were obtained respectively 12.62%, 13.23%, and 12.97%. This shows that the nitrocellulose from the hemp plant (Boehmeria nivea) can be used for propellants. Keywords: Hemp, nitrocellulose, nitration, triethylamine, propellant

In Situ Monitoring of Mechanochemical Covalent Organic Framework Formation Reveals Templating Effect of Liquid Additive

Covalent organic frameworks (COFs) have emerged as a new class of molecularly precise, porous functional materials characterized by a broad structural and chemical versatility, leading to a diverse range of applications. Despite the increasing popularity of COFs, fundamental aspects of their formation are poorly understood and profound experimental insights into their formation processes are still lacking. Here we use a combination of in situ X-ray powder diffraction and Raman spectroscopy to elucidate the reaction mechanism of mechanochemically synthesized imine COFs, leading to the observation of key reaction intermediates. Real-time monitoring provides experimental evidence of templating effects by the liquid additive for the subsequent pore formation and layer assembly. Moreover, the solid-state catalyst scandium triflate Sc(OTf)₃ is revealed to be instrumental in directing the reaction kinetics and mechanism, resulting in products with crystallinity and porosity en par with solvothermally synthesized COFs. This work highlights the potential of mechanochemistry as a green synthetic route towards COF synthesis, and emphasizes the subtle interplay between choice of liquid additives, catalysts, and activation procedure.<br>

In Situ Monitoring of Mechanochemical Covalent Organic Framework Formation Reveals Templating Effect of Liquid Additive

Covalent organic frameworks (COFs) have emerged as a new class of molecularly precise, porous functional materials characterized by a broad structural and chemical versatility, leading to a diverse range of applications. Despite the increasing popularity of COFs, fundamental aspects of their formation are poorly understood and profound experimental insights into their formation processes are still lacking. Here we use a combination of in situ X-ray powder diffraction and Raman spectroscopy to elucidate the reaction mechanism of mechanochemically synthesized imine COFs, leading to the observation of key reaction intermediates. Real-time monitoring provides experimental evidence of templating effects by the liquid additive for the subsequent pore formation and layer assembly. Moreover, the solid-state catalyst scandium triflate Sc(OTf)₃ is revealed to be instrumental in directing the reaction kinetics and mechanism, resulting in products with crystallinity and porosity en par with solvothermally synthesized COFs. This work highlights the potential of mechanochemistry as a green synthetic route towards COF synthesis, and emphasizes the subtle interplay between choice of liquid additives, catalysts, and activation procedure.<br>

Misleading Focal Clinical, Neurophysiologic, and Imaging Features in 2 Children With Generalized Epilepsy Who Underwent Invasive Electroencephalographic (EEG) Monitoring

Children and adults with genetic generalized epilepsy may have focal clinical seizure symptoms as well as electroencephalographic (EEG) findings. This may pose a diagnostic challenge to clinicians, especially when concomitant focal neuroimaging findings exist and the epilepsy is medically refractory. We sought to highlight the challenges that clinicians may face through the description of 2 children with suspected genetic generalized epilepsy who had both focal seizure symptoms and EEG/neuroimaging findings and underwent invasive EEG monitoring. Ultimately, invasive monitoring failed to demonstrate a focal origin for the seizures in both cases, and instead confirmed the presence of genetic generalized epilepsy. We demonstrate that ≥3-Hz generalized monomorphic spike and waves are less likely to represent secondary bilateral synchrony, that focal neuroimaging findings may not always be causal and that repeated hyperventilation is an essential activation procedure for genetic generalized epilepsy.

Cleaning Efficacy of the XP-Endo® Finisher Instrument Compared to Other Irrigation Activation Procedures: A Systematic Review

Background. One of the most important aims of an endodontic treatment is to obtain the complete removal or reduction of root canal remaining filling material: Smear layer, bacteria, intra-canal medicaments. To meet this requirement, several irrigation activation techniques have been proposed. Our systematic review examined studies which analyzed the XP-endo Finisher (XPF) instrument efficacy in removing root canal debris during initial endodontic treatment or retreatment, comparing it with the efficacy of other irrigation activation protocols, such as passive ultrasonic irrigation (PUI), laser activation procedure (Er:YAG), and Self-Adjusting File system (SAF). Methods. A systematic review was conducted using PubMed, Chocrane Library, and Scopus databases, identifying 51 items. Thirty-four articles were excluded based on title, abstract, full text, and language. Seventeen randomized controlled trials were selected and consequently submitted to quality assessment and data collection. Results. Conventional needle irrigation (CNI) is the less effective irrigation technique, but it is still unclear whether XPF is able to guarantee greater debris removal than the PUI technique. Er:YAG laser has been proven to be more effective in apical third than XPF instrument. Conclusions. Further investigations are needed in order to establish which final irrigation activation procedure could reach the maximum root canal debris reduction.