An artificial intelligence-based dental semantic search engine as a reliable tool for dental students and educators.

PURPOSE/OBJECTIVES: This study proposes the utilization of a Natural Language Processing tool to create a semantic search engine for dental education while addressing the increasing concerns of accuracy, bias, and hallucination in outputs generated by AI tools. The paper focuses on developing and evaluating DentQA, a specialized question-answering tool that makes it easy for students to seek information to access information located in handouts or study material distributed by an institution. METHODS: DentQA is structured upon the GPT3.5 language model, utilizing prompt engineering to extract information from external dental documents that experts have verified. Evaluation involves non-human metrics (BLEU scores) and human metrics for the tool's performance, relevance, accuracy, and functionality. RESULTS: Non-human metrics confirm DentQA's linguistic proficiency, achieving a Unigram BLEU score of 0.85. Human metrics reveal DentQA's superiority over GPT3.5 in terms of accuracy (p = 0.00004) and absence of hallucination (p = 0.026). Additional metrics confirmed consistent performance across different question types (X2 (4, N = 200) = 13.0378, p = 0.012). User satisfaction and performance metrics support DentQA's usability and effectiveness, with a response time of 3.5 s and over 70% satisfaction across all evaluated parameters. CONCLUSIONS: The study advocates using a semantic search engine in dental education, mitigating concerns of misinformation and hallucination. By outlining the workflow and the utilization of open-source tools and methods, the study encourages the utilization of similar tools for dental education while underscoring the importance of customizing AI models for dentistry. Further optimizations, testing, and utilization of recent advances can contribute to dental education significantly.

Accelerated mineralization of textile wastewater under 222 nm irradiation from Kr/Cl2 excilamp: an environmentally friendly and energy efficient approach.

The textile dyeing and manufacturing industry is the major producer of significant amounts of wastewater that contain persistent substances such as azo dyes that require adequate remediation measures. Far ultraviolet at 222 nm light may provide an advantage for contaminants degradation as compared to conventional UV sources (254 nm). In this paper, the degradation of reactive black 5 (RB5) in artificial wastewater has been performed using a 222 nm Kr/Cl2 excimer source under direct photolysis and an advanced oxidation process using TiO2/H2O2. The solution pH, catalyst concentration, 222 nm intensity, initial concentration of dye, and addition of H2O2 influence the degradation rate constant. The molar absorption coefficient, quantum yield of RB5 at 222 nm and the electrical energy per order (EEO) from different treatment methods have been reported. RB5 shows 1.26 times higher molar absorption at 222 nm than at 254 nm. The EEO for excimer-222/H2O2 ( ∼ 13 kWh/m3) is five times lower than that of the excimer-222/TiO2 process, which makes the process energy efficient. The degradation of wastewater has been carried out at three distinct pH values (2, 6, and 10), and the pH level of 10 exhibited the highest degree of degradation. The degradation rate in the alkaline medium is 8.27 and 2.05 times higher than in the acidic or ambient medium. Since textile effluent is highly alkaline, this result is significant, as no neutralization of the wastewater is required, and direct treatment is possible. A possible degradation pathway has been established based on Fourier transform infrared spectroscopy (FTIR) and high resolution mass spectroscopy (HRMS) analysis. The phytotoxicity of the treated wastewater has also been evaluated for its suitability for reuse in agriculture. The study reveals that the excimer-222/H2O2 treated wastewater significantly enhanced the germination percentage of Raphanus sativus seed (97%) compared to dye wastewater-grown seeds (75%). This work offers crucial information for future studies on the direct and indirect photolysis of azo dyes, as well as insight into the process of RB5 degradation under Kr/Cl2 excimer radiation.

Environmentally Friendly UV-C Excimer Light Source with Advanced Oxidation Process for Rapid Mineralization of Azo Dye in Wastewater.

Wastewater discharged from the textile industry contains approximately 15% unfixed dyes, predominantly 60-70% azo dyes. These unfixed dyes are a major environmental concern due to their persistence and potential toxicity. In this paper, an environmentally friendly mercury-free XeI* excilamp emitting 253 nm UV light is reported, and the same has been utilized for the degradation of azo dyes using the advanced oxidation process (AOP) with TiO2/H2O2. A new process is developed in which one electrode of excilamp is coated with TiO2 nanoparticles that improves the efficiency of the dye degradation. Additionally, the effects of varying TiO2 loading concentrations, XeI*-excimer light intensity, starting dye concentration, suspension pH, and H2O2 addition are examined. The outcomes of this study confirm 13 times faster degradation in XeI*-excimer/H2O2 than in XeI*-excimer/TiO2, attributed to an abundance of hydroxyl radicals generated by the modified XeI*-excimer/H2O2. Also, the degradation of RB5 in the modified XeI*-excimer/H2O2 is 2.3 times faster as compared to that of the bare electrode XeI*-excimer/H2O2. A more than 95% reduction in chemical oxygen demand has been achieved in 40 min in the case of XeI*-excimer/H2O2. In this study, a maximum energy yield of 5712 mg/kWh is reported. Furthermore, a high degree of degradation is found in the alkaline medium (pH 10). Because textile effluent is highly alkaline, this result is significant, and direct treatment of azo dyes is possible. The use of the developed source in industrial applications appears to be highly promising based on testing on a real wastewater matrix. The treated effluent has been utilized to study its reusability for agricultural purposes on the germination of radish seeds in soil, and ∼26% enhanced germination has been observed compared to dye wastewater.

Synthesis and Spectroscopic Investigations of Sm3+ Activated ZrO2 and Na2ZrO3 as Warm Light Phosphors.

In this work, we investigate how the structural and optical characteristics of ZrO2 and Na2ZrO3 are influenced by Sm3+ ion doping. Urea-assisted combustion approach is employed by varying the molar concentration of Sm3+ ions in both the host lattices. XRD pattern revealed the monoclinic crystal system for both samples. XPS investigation has been examined to acquire the chemical information of the samples. FESEM is used to identify the morphology of the samples. The optimum molar concentrations of Sm3+ doped ZrO2 and Na2ZrO3 phosphors, as per photoluminescence (PL) findings, are 1.5 mol% and 2 mol%, respectively. CIE coordinates of ZrO2:Sm3+ and Na2ZrO3:Sm3+ are found to be (x = 0.59, y = 0.41) and (x = 0.61, y = 0.39) that corresponds to the amber region of color gamut. The optical bandgap for the synthesized samples is estimated using the UV-Vis diffuse reflectance spectra and the obtained values for the optimal concentration of dopant (Sm3+) in the ZrO2 and Na2ZrO3 samples are 4.61 and 4.94 eV, respectively. The findings of the study reveal that the synthesized phosphors may be utilized as warm light phosphors and be a promising candidate for amber light-emitting diodes (LEDs).

Analysis of a UV photocatalytic oxidation-based disinfection system for hydroxyl radicals, negative air ions generation and their impact on inactivation of pathogenic micro-organisms.

This work presents a large-scale surface disinfection system, which has a unique lantern arrangement of ultraviolet-C (UV-C) light (254 nm) in conjunction with nanotechnology in a protective biosafety environment. Shadow regions are best dealt in this system by the generation of hydroxyl radicals (•OH) and negative air ions at sites where UV light cannot penetrate. More than 35 000 negative air ions/cm3 along with •OH were produced continuously in the disinfection chamber through the advanced photocatalytic oxidation process [UV-C + titanium dioxide (TiO2)]. The arrangement has been made to provide an optimized UV irradiation (∼2 mW/cm2) throughout the disinfection system. In order to distinguish between effects arising from (i) the action of UV dose alone and (ii) the action of UV dose along with •OH and negative air ions, E. coli and P. aeruginosa were chosen for bacterial testing and two interventions were made. The first intervention involved placing only UV lamps in the disinfection chamber to see the effect of only UV dose on bacterial inactivation efficiency. The second intervention involved placing the TiO2 nanoparticle coated aluminum plates along with UV lamps; this allows for the generation of negative air ions and •OH inside the disinfection chamber and enhanced bacterial inactivation efficiency. More than 95% bacterial inactivation efficiency has been reported in the case of UV-C + TiO2 compared to only 77% in UV only at the same time interval (90 s).

Efficient deactivation of aerosolized pathogens using a dielectric barrier discharge based cold-plasma detergent in environment device for good indoor air quality.

Air pollution is one of the top 5 risks causing chronic diseases according to WHO and airborne transmitted pathogens infection is a huge challenge in the current era. Long living pathogens and small size aerosols are not effectively dealt with by the available indoor air purifiers. In this work, a dielectric barrier discharge (DBD) based portable cold-plasma detergent in environment device is reported and its disinfection efficiency has been analyzed in the indoor environment of sizes up to 3 × 2.4 × 2.4 m3. The deactivation efficiency of total microbial counts (TMCs) and total fungal counts (TFCs) is found to be more than 99% in 90 min of continuous operation of the device at the optimized parameters. The complete inactivation of MS2 phage and Escherichia coli bacteria with more than 5 log reduction (99.999%) has also been achieved in 30 min and 90 min of operation of the device in an enclosed environment. The device is able to produce negative ions predominantly dominated by natural plasma detergent along with positive ions in the environment similar to mother nature. The device comprises a coaxial DBD geometry plasma source with a specially designed wire mesh electrode of mild steel with a thickness of 1 mm. The need for feed gas, pellets and/or differential pressure has been eliminated from the DBD discharge source for efficient air purification. The existence of negative ions for more than 25 s on average is the key advantage, which can also deactivate long living pathogens and small size aerosols.

GWAS and genomic prediction for pre-harvest sprouting tolerance involving sprouting score and two other related traits in spring wheat.

In wheat, a genome-wide association study (GWAS) and genomic prediction (GP) analysis were conducted for pre-harvest sprouting (PHS) tolerance and two of its related traits. For this purpose, an association panel of 190 accessions was phenotyped for PHS (using sprouting score), falling number, and grain color over two years and genotyped with 9904 DArTseq based SNP markers. GWAS for main-effect quantitative trait nucleotides (M-QTNs) using three different models (CMLM, SUPER, and FarmCPU) and epistatic QTNs (E-QTNs) using PLINK were performed. A total of 171 M-QTNs (CMLM, 47; SUPER, 70; FarmCPU, 54) for all three traits, and 15 E-QTNs involved in 20 first-order epistatic interactions were identified. Some of the above QTNs overlapped the previously reported QTLs, MTAs, and cloned genes, allowing delineating 26 PHS-responsive genomic regions that spread over 16 wheat chromosomes. As many as 20 definitive and stable QTNs were considered important for use in marker-assisted recurrent selection (MARS). The gene, TaPHS1, for PHS tolerance (PHST) associated with one of the QTNs was also validated using the KASP assay. Some of the M-QTNs were shown to have a key role in the abscisic acid pathway involved in PHST. Genomic prediction accuracies (based on the cross-validation approach) using three different models ranged from 0.41 to 0.55, which are comparable to the results of previous studies. In summary, the results of the present study improved our understanding of the genetic architecture of PHST and its related traits in wheat and provided novel genomic resources for wheat breeding based on MARS and GP. Supplementary Information: The online version contains supplementary material available at 10.1007/s11032-023-01357-5.

Future of TABST and LABST in the Indian Pharmacopoeia Monographs A Humane Society International/India Workshop Report.

Humane Society International India (HSI India) organized and facilitated a workshop on the 'Future of Target Animal Batch Safety Test (TABST) and Laboratory Animal Batch Safety Test (LABST) in the Indian Pharmacopoeia (IP) Monographs'. The workshop hosted key Indian regulators from the Indian Pharmacopoeia Commission (IPC) and the Central Drugs Standard Control Organization (CDSCO), industry representatives from the Indian Federation of Animal Health Companies (INFAH), Asian Animal Health Association (AAHA), and international experts representing the European Directorate for the Quality of Medicines (EDQM), the International Cooperation on Harmonization of Technical Requirements for Registration of Veterinary Medicinal Products (VICH), and multinational veterinary products manufacturers. The workshop was organized to encourage a bidirectional flow of information and to discuss the deletion of TABST and LABST from the veterinary vaccine monographs in the IP. This workshop was built from the symposium held by Humane Society International on the 'Global Harmonization of Vaccine Testing Requirements' held in 2019. This report details the outcomes of the workshop with proposed activities to be taken up as part of the next steps for the elimination or waiving of these tests.

An in-vitro analysis to evaluate the disinfection effectiveness of Cold Atmospheric Pressure (CAP) plasma jet in Enterococcus faecalis infected root canals.

Cold Atmospheric Pressure (CAP) plasma has shown successful antibacterial efficacy in different medical applications which have prompted researchers to explore its possible use in endodontics. The aim of the present study was to comparatively evaluate the disinfection effectiveness of CAP Plasma jet with 5.25% sodium hypochlorite (NaOCl) and Qmix in Enterococcus Faecalis infected root canals at different time intervals (2, 5, and 10 min). 210 single-rooted mandibular premolars were chemomechanically prepared and infected with E. faecalis. The test samples were exposed to CAP Plasma jet, 5.25% NaOCl, and Qmix for 2, 5, and 10 min. The residual bacteria from the root canals if any were collected and evaluated for colony-forming units (CFUs) growth. ANOVA and Tukey's tests were used to evaluate the significant difference between treatment groups. 5.25% NaOCl showed significantly more antibacterial effectiveness (<0.001) when compared with all other test groups except Qmix at 2 and 10 min of exposure time. A minimum contact time of 5 min with 5.25% NaOCl is recommended to get zero bacterial growth in E. faecalis infected root canals. QMix requires a minimum contact time of 10 min to achieve optimal CFUs reduction and CAP plasma jet requires a minimum contact time of 5 min to achieve substantial CFUs reduction.

Comparison of smear layer removing efficacy of Cold Atmospheric Pressure (CAP) Plasma Jet with different chelating agents. An ex-vivo study.

The present study aimed to assess the effectiveness of different final irrigation regimens (Cold Atmospheric Pressure Plasma Jet, MTAD, and EDTA) in removing the smear layer from intra-radicular dentin using a Scanning Electron Microscope (SEM). Eighty-four mandibular premolars were prepared with ProTaper Universal hand files and were equally divided into four groups i.e. Normal saline (control), EDTA, MTAD and CAP Plasma Jet. Prepared samples in the control, EDTA and MTAD groups were irrigated with 5 milliliters of the irrigant, and it was retained for 2 min. In the CAP Plasma Jet group, the plasma plume was directed towards the canal lumen for 2 min. The smear layer removal of all the groups was evaluated at the coronal, middle and apical thirds. Statistical analysis was performed using Kruskal-Wallis test followed by Dunn's test. Evaluation by SEM showed that the smear layer removal ability of MTAD and EDTA were significantly better than CAP Plasma Jet (p < 0.05). While CAP Plasma Jet showed results comparable to EDTA in the coronal third. In the middle and apical third of the canal, its effect was comparable to the control group (p > 0.05). MTAD and EDTA aided in better smear layer removal than the CAP Plasma Jet in the coronal, middle, and apical third of the test samples. CAP Plasma jet performed better in the coronal third.

Photocatalytic oxidation conveyor "PCOC" system for large scale surface disinfection.

In this paper, we present a surface decontamination system that substitutes traditional chemicals and scrubbing agents, which will be useful for the general public during a pandemic. The technique is based on a hybrid process in which UV-C light and its photons interact with metal oxide nano-catalysts to generate hydroxyl radicals, which can enhance the deactivation process, and the system can work even in the shadow regions via a dry process. The optimum number of UV light sources in combination with TiO2 nanoparticles catalysts on aluminum plates have been used synergistically in the system. The UV dose in the disinfection chamber has been optimized, which is between 60 and 500 mJ/cm2 throughout the disinfection chamber. The concentration of hydroxyl radicals is reported more than 25 000 ions/cm3 within the disinfection chamber. These ions are circulated throughout the disinfection volume. The disinfection efficiency has been tested on bacteria and spores, and the obtained results are correlated. Around 8 log reductions in the counts of the test bacteria of Escherichia coli and Klebsiella pneumoniae have been achieved in just 2 min of exposure in the continuous operation of the system. Tests have also been performed on Geobacillus stearothermophilus spores, and the method described here is the result of multiple tests, a review of the scientific literature, and the incorporation of current laboratory practice. The deactivation tested in the system is larger than that of known bacteria and viruses in terms of UV-doses, signifying its utility during the pandemic.

ISAR Consensus Guidelines on Safety and Ethical Practices in In vitro Fertilization Clinics.

STUDY QUESTION: What are the Safe and Ethical practices for ART applicable in INDIA? WHAT IS ALREADY KNOWN: The Indian IVF industry is booming; with mushrooming of assisted reproductive technology (ART) clinics in the country, the need for regulation is immense. The ISAR has taken up this initiative to lead the way forward in establishing practice guidelines for the safe and ethical use of ARTs in our country. These guidelines discuss the points to consider before the starting of an IVF unit, to the designing of the laboratory, the staffing pattern and experience recommendations, laboratory safety guidelines, documentation and patient traceability, gamete traceability, handling biological material, the consumables and media, and different consents and checklists and also propose key performance indicators for the Indian scenario. STUDY DESIGN SIZE DURATION: This is the report of a 2-day consensus meeting where two moderators were assigned to a group of experts to collate information on safe and ethical ivf practices in INDIA. This meeting utilised surveys, available scientific evidence and personal laboratory experience into various presentations by experts on pre-decided specific topics. PARTICIPANTS/MATERIALS SETTING METHODS: Expert professionals from ISAR representing clinical and embryology fields. MAIN RESULTS AND THE ROLE OF CHANCE: The report is divided in various components including the regulations, the various requirements for an ART center, qualifications and trainings, recommendations on good practices and quality management: the report and recommendations of the expert panel reflect the discussion on each of the topics and try to lay down good practice points for labs to follow. LIMITATIONS REASONS FOR CAUTION: The recommendations are solely based on expert opinion. Future availability of data may warrant an update of the same. WIDER IMPLICATIONS OF THE FINDINGS: These guidelines can help labs across the country to standardise their ART services and improve clinical outcomes. STUDY FUNDING/COMPETING INTERESTS: The consensus meeting and writing of the paper was supported by funds from CooperSurgical India.

One-pot three component synthesis of substituted dihydropyrimidinones using fruit juices as biocatalyst and their biological studies.

New and facile one-pot three component approach for the synthesis of substituted dihydropyrimidinones derivatives (4a-4h) from reaction of equimolar substituted aldehydes (1a-1h), methyl acetoacetate (2a) and urea (3a) in presence of nature derived catalyst viz. Cocos nucifera L. juice, Solanum lycopersicum L. juice and Citrus limetta juice, commonly known as coconut juice, tomato juice and musambi juice respectively, at room temperature has been carried out. All synthesized compounds were evaluated for in vitro herbicidal activity against Raphanus sativus L. (Radish seeds). The compounds (4a-4h) were also screened for their antifungal activity against Rhizoctonia solani and Colletotrichum gloeosporioides by poisoned food techniques method. Antibacterial activity was also studied against Erwinia cartovora and Xanthomonas citri by inhibition zone method. From activity data, it was found that compounds 4g and 4d were most active against Raphanus sativus L. (root) and Raphanus sativus L. (shoot) respectively. Compounds 4f and 4c was found most active against Rhizoctonia solani and Colletotrichum gloeosporioides fungus respectively at highest concentration. Compound 4g has shown maximum inhibition zone i.e. 1.00-5.50 mm against Erwinia cartovora at 2000 µg/mL concentration. Maximum Xanthomonas citrii growth was inhibited by compounds 4f showing inhibition zone 4.00-12.00 mm at highest concentration. Short reaction time, high yields, mild reaction condition and simple work-up are some merits of present methodology.

Investigation of Antimicrobial Activity of DBD Air Plasma-Treated Banana Fabric Coated with Natural Leaf Extracts.

This paper focuses on the investigation of the antimicrobial activity of banana fabric treated with dielectric barrier discharge (DBD) plasma. The fabric was exposed to air plasma for varying treatment times of 1-5 min followed by coating with green tea (Camellia sinensis) and tulsi (Ocimum sanctum) leaf extracts at five different concentrations. The treated fabric was evaluated in terms of surface wettability by a range of tests like wet-out time analysis, hydrophilicity test, and contact angle measurements. The functional groups formed on the treated fabric were analyzed by attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy. The surface morphology was studied using atomic force microscopy (AFM) and scanning electron microscopy (SEM), and the surface chemistry was studied using X-ray photoelectron spectroscopy (XPS). The FTIR and XPS analysis results indicate that the plasma-treated fabric was found to have a higher concentration of polar groups (-COOH, -OH, -C=O) that has improved surface hydrophilicity and functionality. The antimicrobial activity of the treated fabric surface was determined both qualitatively and quantitatively by the agar plate method and modified Hoenstein test, against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. An improvement in the antimicrobial property was observed in plasma-treated banana fabric coated with natural extracts even after four washing cycles. This study suggests that air DBD plasma treatment followed by the absorption of tea/tulsi leaf extracts can serve as a better tool for developing natural antimicrobial textiles, which could serve the purpose in medical and healthcare sectors concerning recent times. It has eventually led to better absorption of plant extracts, thereby increasing their antimicrobial activity.

Prevalence and determinants of caesarean section in South and South-East Asian women.

BACKGROUND: Caesarean section is considered a relatively preferable and safe method of delivery as compared to normal delivery. Since the last decade, its prevalence has increased in both developed and developing countries. In the context of developing countries viz., South Asia (the highest populated region) and South-East Asia (the third-highest populated region), where a significant proportion of home deliveries were reported,however, the preference for, caesarean delivery and its associated factors are not well understood. OBJECTIVE: To study the caesarean delivery in the South and South-East Asian countries and to determine the factors associated with the preference for caesarean delivery. METHODOLOGY: Demographic and Health Survey Data on from ever-married women of nine developing countries of South and South-East Asia viz., Vietnam, India, Maldives, Timor-Leste, Nepal, Indonesia, Pakistan, Bangladesh, and Cambodia have been considered. Both bivariate and binary logistic regression models were used to estimate the propensity of a woman undergoing for caesarean delivery and to assess the influence of maternal socioeconomic characteristics towards the preference for caesarean delivery. RESULTS: Obtained results have shown an inclination of caesarean delivery among urban than rural women and are quite conspicuous, but is found to be underestimated mostly among rural women. Caesarean delivery in general is mostly predisposed among women whose baby sizes are either very large or smaller than average, have a higher level of education and place of delivery is private medical institutions. The logistic regression also revealed the influence of maternal socioeconomic characteristics towards the preference for caesarean delivery. Based on nine South and South-East Asian countries an overall C-section prevalence of 13%, but based on institutional births its increase to 19%. The forest plot demonstrated that a significant inclination of C-section among urban than rural regions. In Meta-Analysis, very high and significant heterogeneity among countries is observed, but confirms that in terms of prevalence of C-section all of the countries follow independent pattern. CONCLUSION: Study of seven urban and four rural regions of nine South and South- East Asian countries showed, a significant inclination towards the caesarean delivery above the more recent outdated WHO recommended an optimal range of 10-15%and are associated maternal socioeconomic characteristics. In order to control unwanted caesarean delivery, the government needs to develop better healthcare infrastructure and along with more antenatal care related schemes to reduce the risks associated with increased caesarean delivery.

Virtual microscopy made economical and effortless using the Foldscope and a smartphone with screen mirroring.

CONTEXT: Virtual Microscopy. AIM: The aim of this study was to demonstrate, as a proof of concept, the integration of a Foldscope, along with a smartphone and screen mirroring devices, into the regular academic teaching program for use with all types of regular slides for economical virtual microscopy. SETTING DESIGN & METHODS: For the purpose of this demonstration, a microscopic slide of a ground section of a tooth, a smartphone (iPhone6), a Foldscope and an Apple TV module were chosen to demonstrate the integration of a low-cost unbreakable microscope along with a smartphone to facilitate immediate viewing, capture, sharing and even projection of the image by screen mirroring, if required, in a classroom setting. CONCLUSION: The Foldscope microscope (Foldscope Instruments, Palo Alto, CA, USA) invented by Manu Prakash is an extremely economical, Origami style, fold to assemble microscope available from popular online retailers at approximately Rupees 500 aimed at simplifying and enabling diagnostics and education worldwide. The Foldscope, integrated with a smartphone, allows for easy screen casting thus proving invaluable as an educational tool by creating an effortless bridge between analogue input and digital output, facilitating instant digitization of slides for viewing, display, communication and storage. This article demonstrates the use of the Foldscope for virtual microscopy in a classroom scenario, by employing the screen mirroring capabilities of a smartphone.

Dielectric Barrier Discharge based Mercury-free plasma UV-lamp for efficient water disinfection.

A structurally simple dielectric barrier discharge based mercury-free plasma UV-light source has been developed for efficient water disinfection. The source comprises of a dielectric barrier discharge arrangement between two co-axial quartz tubes with an optimized gas gap. The outer electrode is an aluminium baked foil tape arranged in a helical form with optimized pitch, while the inner electrode is a hollow aluminium metallic rod, hermetically sealed. Strong bands peaking at wavelengths 172 nm and 253 nm, along with a weak band peaking at wavelength 265 nm have been simultaneously observed due to plasma radiation from the admixture of xenon and iodine gases. The developed UV source has been used for bacterial deactivation studies using an experimental setup that is an equivalent of the conventional house-hold water purifier system. Deactivation studies for five types of bacteria, i.e., E. coli, Shigella boydii, Vibrio, Coliforms and Fecal coliform have been demonstrated with 4 log reductions in less than ten seconds.

A low power miniaturized dielectric barrier discharge based atmospheric pressure plasma jet.

In this paper, a dielectric barrier discharge plasma based atmospheric pressure plasma jet has been generated in a floating helix and floating end ring electrode configuration using argon and helium gases. This configuration is subjected to a range of supply frequencies (10-25 kHz) and supply voltages (2-6 kV) at a fixed rate of gas flow rate (i.e., 1 l/min). The electrical characterization of the plasma jet has been carried out using a high voltage probe and current transformer. The current-voltage characteristics have been analyzed, and the consumed power has been estimated at different applied combinations for optimum power consumption at maximum jet length. The obtained optimum power and jet length for argon and helium gases are 12 mW and 32 mm, and 7.7 mW and 42 mm, respectively. It is inferred that besides the electrode configurations, the discharge gas is also playing a significant role in the low power operation of the cold plasma jet at maximum jet length. The obtained results are interpreted on the basis of penning processes.