Graphitic Carbon Nitride as a Sustainable Photocatalyst Material for Pollutants Removal. State-of-the Art, Preliminary Tests and Application Perspectives

Photocatalysis is an attractive strategy for emerging pollutants remediation. Research towards the development of new, efficient and effective catalytic materials with high activity under wide irradiation spectra is a highly active sector in material science. Various semiconductor materials have been employed as photocatalysts, including TiO2, SrTiO3, CdS, BiVO4, Ta3N5, TaON, Ag3PO4, and g-C3N4. The latter is a metal-free, low cost polymer, providing high adsorption and catalytic properties, shown to be promising for photocatalysis applications under visible light. Furthermore, g-C3N4 composites are among the most promising advanced photocatalytical materials that can be produced by green synthesis processes. In this paper, the state-of-the-art of g-C3N4 applications is reviewed, and application perspectives are discussed. Photocatalysis tests with g-C3N4 under Xenon irradiation were performed to gather first-hand information to improve photoreactor design. Xenon light spectrum appears to be a suitable radiation source to replace direct sunlight in engineered pollutants removal processes catalyzed by g-C3N4, in lieu of other currently used heterogeneous photocatalysis processes (e.g., TiO2-UV). LED sources are also very promising due to higher energy efficiency and customizable, catalyzer-specific irradiation spectra.

The evolution of headlight devices in the work of otorhinolaryngologists

Invention and improving the methods of ENT examination are closely connected with the technological inventions of the 19th and 20th centuries. The invention of the classical exam head mirror in 1861 and improvement of the manufacturing of compact and powerful sources of light (filament lamps) at the time caused the researchers to create new devices for ENT examination. In particular, a head-mounted electro-mirror was created, the principle of which later became the basis for the development of fiber-optic headlamps. The emergence of powerful halogen and xenon light sources in the mid-20th century and the use of fiber-optics technology led to the development of fundamentally new mirror less headlamps. The traditional head-mounted reflector has gradually disappeared from the practice of an otolaryngologist. For our part, we can see how fiber-optic headlamps have been progressively replaced by heavy-duty LED headlamps over the last nine years. In order to determine the effectiveness of each available headlamp type and to answer the question of whether there is a benefit in using and maintaining a reflector headlamp, and to determine which current head-lamps are effective, we conducted our own research. Summing up the results, we came to the conclusion that despite its historic role in the development of otorhinolaryngology, the headlamp reflector through its low, in comparison with modern illuminators, characteristics have lost its relevance and, apparently, nowadays can serve as a museum exhibit. The head-mounted LED illuminator, a 21st century device, is gaining in popularity and is gradually becoming the standard for use in primary ENT diagnosis and during otorhinolaryngological surgical interventions. Its features such as full autonomy, lightweight, ease of use – especially the alignment of the light beam with the surgeon's eye – long operating time without recharging the battery (7 to 30 days) – depending on the manufacturer and the workload of the device – is beyond competition with any other head-mounted device for ENT organ examination.

Novel Photosynthesis And Characterization of 4-(5,7- Dichloro-8ah-chromene-2-yl)-n, N-dimethylaniline from Its Chalcone Isomer

In the present study, trans-3-(2,4-dichlorophenyl)-1-(4-(dimethylamino)phenyl)prop-2-en-1-one (trans 2,4-dimethyl amino chalcone) was synthesized by Claisen-Schmidt reaction in the presence of aqueous alcoholic alkali solution by condensation of a substituted acetophenone with substituted benzaldehydes, Then, The photosynthesis of 4-(5,7-dichloro-8aH-chromen-2-yl)-N,N-dimethylaniline (2,4-dimethylamino chromene) was accomplished from the irradiation of the( trans 2,4-dimethyl amino chalcone) with xenon light. The products were characterized by UV-Visible, FT-IR, 1HNMR, thin layer chromatography Elemental analysis(CHNO) and liquid chromatography-quadrupole-time-of-flight mass spectrometry (LC-Q-ToF-MS).

SURG-20. USE OF NICO MYRIAD NOVUS DEVICE WITH LIGHT SOURCE AND REAL-TIME STEREOTACTIC NAVIGATION TO OPTIMIZE SURGICAL RESECTION OF DEEP-SEATED TUMORS

Maximal and safe surgical resection remains a critical component of the standard of care for patients with brain tumors. Stereotactic navigation tools are often incorporated into the surgical planning and implementation. The NICO Myriad NOVUS device couples a light source with the resecting tip to allow enhanced visualization of the surgical cavity and surrounding anatomical structures. At the Cleveland Clinic, we were the first group in the U.S. to start utilizing this augmented technology to maximize the resection of particularly deep-seated brain tumors, using the xenon light and real-time stereotactic navigation of the tool tip with the BrainLAB cranial setting. The navigated tip allows us to reach the deep corners of tumors with or without a tubular retracting device by sparing large corticotomies. Furthermore, the light source within the handheld device is easier to handle and manipulate than a large microscope to illuminate the surgical cavity. In addition, this new tool allows for automated tumor and peri-tumoral tissue harvesting, annotating each sample by location intraoperatively, as well as biological preservation of the harvested tissue for post-surgical molecular analysis. We describe the techniques and advantages of using this novel technology in patients while following and preliminarily reporting their surgical outcomes. With the emergence of novel technological advances, we must adapt as neurosurgeons and develop innovative methods to optimize the surgical resection of brain tumors.

A Selective Synthesis of TaON Nanoparticles and Their Comparative Study of Photoelectrochemical Properties

A simplified ammonolysis method for synthesizing single phase TaON nanoparticles is presented and the resulting photoelectrochemical properties are compared and contrasted with as-synthesized Ta2O5 and Ta3N5. The protocol for partial nitridation of Ta2O5 (synthesis of TaON) offers a straightforward simplification over existing methods. Moreover, the present protocol offers extreme reproducibility and enhanced chemical safety. The morphological characterization of the as-synthesized photocatalysts indicate spherical nanoparticles with sizes 30, 40, and 30 nm Ta2O5, TaON, and Ta3N5 with the absorbance onset at ~320 nm, 580 nm, and 630 nm respectively. The photoactivity of the catalysts has been examined for the degradation of a representative cationic dye methylene blue (MB) using xenon light. Subsequent nitridation of Ta2O5 yields significant increment in the conversion (ζ: Ta2O5 < TaON < Ta3N5) mainly attributable to the defect-facilitated adsorption of MB on the catalyst surface and bandgap lowering of catalysts with Ta3N5 showing > 95% ζ for a lower (0.1 g) loading and with a lamp with lower Ultraviolet (UV) content. Improved Photoelectrochemical performance is noted after a series of chronoamperometry (J/t), linear sweep voltammetry (LSV), and electrochemical impedance spectroscopy (EIS) measurements. Finally, stability experiments performed using recovered and treated photocatalyst show no loss of photoactivity, suggesting the photocatalysts can be successfully recycled.

Prolonged intra-operative thermal exposure in endoscopic ear surgery: is it really safe?

ObjectiveThe aim of this study was to assess change in temperature, audiometric outcomes and post-operative complications following exposure to different light sources during endoscopic ear surgery.MethodA total of 64 patients diagnosed with chronic otitis media with central perforation and pure conductive hearing loss underwent endoscopic type 1 tympanoplasty. The patients were randomised into two groups based on the light source used: xenon or light-emitting diode. Temperature was measured using a K type thermocouple at the promontory and round window niche. Mean temperature change with respect to operating time, mean audiometric change, incidence of vomiting in the first 24 hours, vertigo and tinnitus at the end of the first week were observed.ResultsMean temperature change showed a statistically significant difference with increasing length of operating time with the xenon light source and when the two light sources were compared for a particular time interval. Mean audiometric change showed statistically significant deterioration at higher frequencies (4, 6 and 8 kHz) with the xenon light source but only at 8 kHz for the light emitting diode source. When the mean audiometric change was compared between light sources for a particular frequency, statistical significance was found at 4, 6 and 8 kHz. Post-operative complications were vomiting, vertigo and tinnitus (p-values of 0.042, 0.099 and 0.147, respectively, between two groups).ConclusionLight emitting diodes are associated with less significant middle-ear temperature rises and audiometric changes at higher frequencies when compared to xenon light sources. Hence, xenon should be replaced with cooler light sources.

Abatement efficiency and fate of EPA-Listed PAHs in aqueous medium under simulated solar and UV-C irradiations, and combined process with TiO2 and H2O2

Photolytic degradation of dissolved compounds of 16 EPA-Listed PAHs in aqueous medium, exposed to ultraviolet/ titanium dioxide (UV-C/TiO2), xenon light/ titanium dioxide (Xe/TiO2), xenon light/ hydrogen peroxide (Xe/H2O2) and ultraviolet/ hydrogen peroxide (UV-C/H2O2) was studied. The compounds which detected above detection limit of applied analytical method and instrument include: naphthalene (Nap), acenaphthylene (Acy), acenaphthene (Ace), fluorene (Flu), fluoranthene (Fln) and pyrene (Pyr) survived. A time-course experiment (0, 1, 2, 5, 12 min) was performed to determine the fate of PAHs profile along treatments. After accomplishment of the removal process ∑6 PAHs ranked as follow: UV-C/TiO2 > Xe/TiO2 > UV-C > Xe > Xe/H2O2, and UV-C /H2O2 with estimated values of 76.38, 23.02, 22.55, 2.78, 0.00 and 0.00% of the concentration values at the beginning of the treatment, respectively. High efficiency of Xe/H2O2 treatment process (100.00%) at the end of treatment and the structure of residual PAHs which changed to the lighter compounds (2,3-ringed PAHs) before accomplishment of the removal process were proven. Generally, low resistance of Fln to all treatment conditions was observed. Total removal of Nap was considered to be a characteristic PAH compound for completion of the removal of PAHs. Mutate of parent PAH compounds and intermediates were analyzed by gas chromatography-mass spectrometry (GC-MS) and the results suggest the evaluating the toxicity of the treated water due to by-product formation concerns.