RESUMO
The innovative approach of harnessing abundant solar energy to facilitate water purification holds great potential for addressing a diverse range of water-related challenges. Utilizing the same method of photothermal desalination is highly promising, sustainable, and cost effective. However, in photothermal desalination, generally, steam is generated at the liquid-air interface. Despite its immense potential, this results in a lower evaporation rate and is prone to salt fouling. Therefore, to address two main challenges, (1) fouling and (2) maximum interfacial temperature (100 °C), here, we report total contactless photothermal desalination by a translucent thin film coating of Crystalline Nanocellulose (CNC). In contactless photothermal desalination, the active photothermal layer remains in no physical contact with the saline water; thus, automatic antifouling and a temperature above the boiling point of water can be achieved for water purification. In this report, we have sustainably extracted CNC from waste sawdust by a sonochemical extraction method using minimal chemicals. Additionally, the sonoextraction method through cavitation helps in the desulfation of CNC. These thermally stable and highly crystalline CNCs are used in making active translucent photothermal active layers for photothermal desalination. CNCs were well characterized by both microscopic and spectroscopic techniques. In the photothermal desalination, the results show an augmented evaporation rate of â¼3.30 kg/m2·h and virtually infinite recyclability for longer usability. Moreover, the integrated setup reported here comprises an independent module with a highly flexible design that mimics the greenhouse effect for a high solar-to-steam output.
RESUMO
Introduction Chemoradiotherapy plays a major role in the treatment of head and neck cancer (HNC). Persistent dysphagia following primary chemoradiotherapy for head and neck cancers can have a devastating effect on a patient's quality of life. Many studies have shown that the dosimetric sparing of critical structures which were included in swallowing such as the pharyngeal constrictor muscle and larynx can provide improved functional outcomes and better quality of life. However, there are no current randomized studies confirming the benefits of such swallowing-sparing strategies. The aim is to evaluate late dysphagia after chemoradiotherapy for head and neck cancer and to examine its correlation with clinical and dosimetric parameters. Materials and methods The period of this prospective study was from November 2018 to March 2020. Patients were divided randomly in 1:1 ratio into two groups, group 1 and group 2, each with 25 patients. Group 1 was planned by three-dimensional conformal radiotherapy (3D-CRT) technique and group 2 was planned by intensity-modulated radiotherapy technique (IMRT) technique. Treatment was delivered after approval of radiotherapy plan. To evaluate the dose to dysphagia aspiration-related structures (DARS), these structures were contoured and dose-volume histograms were generated. Various dosimetric parameters of DARS were evaluated. Swallowing status was clinically evaluated based on the Radiation Therapy Oncology Group and the Common Terminology Criteria for Adverse Events, version 5. Results A significant advantage was seen with intensity-modulated radiotherapy technique (IMRT) in comparison to three-dimensional conformal radiotherapy (3D-CRT) in terms of mean dose delivered to the pharyngeal constrictor muscles (66.03 Gy vs 68.77 Gy, p=0.003). The mean dose delivered to the combined dysphagia/aspiration-related structures (DARS) was statistically significantly lower in IMRT compared to 3D-CRT (66.15 Gy vs. 70.09 Gy, p<0.001). Other dose-volumes were also reduced in IMRT group (V30: {98.64% vs. 99.88%, p=0.05}; V50: {90.49% vs. 99.02%, p=0.0002}; V60: {83.92% vs. 95.04, p=0.0002}; D50: {70 Gy vs. 71.16 Gy, p=0.001); and D80: {61.18 Gy vs. 67.39 Gy, p=0.01}. Futhermore, the clinical worsening of dysphagia was less common in IMRT group (48% vs. 80%, p=0.039). Conclusion IMRT can reduce the high-dose volumes received by the DARS receiving high doses by sparing these structures through optimization. This may provide a significant additional benefit that could improve dysphagia and hence the quality of life of patients with head and neck cancer.
RESUMO
The present study reports the experimental and theoretical investigation for production of ultra-low sulfur liquid fuels through estimation of various reactive species formed during the reaction with the help of simulation. All the experiments were performed using an ultrasound bath which operates at a frequency of 37 kHz and a theoretical power of 95 W. The presented oxalate-based technique is found to be more efficient with > 93% DBT oxidation within 15 min of reaction time at 25 °C due to formation of reactive species like FeIIC2O4 and [Formula: see text] which accelerate the reaction kinetics. Moreover, we have also investigated the influence of process parameters such as molar ratio of C2O42-/Fe2 +, oxidant concentration, volume ratio of organic to aqueous phase, sulfur concentration, and activation methods of oxidant. The results revealed that catalyst can be reused for several runs without decrease in catalytic activity. The experimental and simulation of cavitation bubble dynamics results revealed that sonochemical effect assists to accelerate the reaction kinetics through formation of free radicals (â¢O, â¢H, â¢OH and HO2â) and other reactive species like O3 and H2O2 generated during transient cavitation. The sono-physical effects of cavitation help to create a fine emulsion in the liquid-liquid heterogeneous system leading to enhanced mass transfer rate by providing more interfacial surface area for occurring chemical reaction.