Estimation of spectroscopic parameters and TL glow curve analysis of Eu3+-activated CaY2O4 phosphor.

The solid-state reaction method was utilised to create a down-conversion phosphor in an air environment in CaY2O4:Eu3+ nanocrystalline material. The calcination temperature was set at 1000 °C, and the sintering temperature was set at 1300 °C. Following annealing, confirmation of the crystallinity quality of the phosphor was accomplished by the use of X-ray diffraction analysis. The particle size was predicted to be 43.113 nm using Scherrer's formula. To produce down-conversion luminescence spectra, an excitation wavelength of 247 nm was applied with a fluorescence spectrophotometer. The PL got increasingly intense as the concentration of the dopant increased. The maximum intensity was measured at 2.0 mol% of Eu3+ ion, which gradually decreased as the concentration increased because of concentration quenching. To analyse spectrophotometric peak determinations, the approach developed by the Commission Internationale de l'Éclairage (CIE) was used. Thermoluminescence (TL) glow curve analysis of the CaY2O4:Eu3+-doped phosphor manufactured here revealed a wide TL centred at 225 °C, which comprised of so many peaks that may be extracted by the computerised glow curve deconvolution (CGCD) approach using glow-fit software. The associated kinetic parameters were then determined. The prepared phosphor may be useful for application in various display devices upon excitation by 247 nm; the prominent 613 nm peak of the Eu3+ ion (5D0 → 7F2) electric dipole transition features a red component. CaY2O4:Eu3+ phosphors show promise as materials for potential use in phosphor-converted white LEDs in the field of solid-state lighting technology. The linear connection that the TL glow curve has with UV dose provides evidence for its possible use in dosimetry.

Optimizing the luminescence efficiency of an europium (Eu3+) doped SrY2O4 phosphor for flexible display and lighting applications.

This research paper reports the synthesis and luminescence study of an Eu3+ activated SrY2O4 phosphor prepared by a modified solid-state reaction method with varying concentrations of Eu3+ ions (0.1-2.5 mol%). X-ray diffraction (XRD) revealed the orthorhombic structure and Fourier transform infrared spectroscopy (FTIR) methods were used to analyse the produced phosphors. Photoluminescence emission and excitation spectra were recorded for varying concentrations of Eu3+ ions, and an optimum concentration of 2.0 mol% was found to produce the highest intensity. Under 254 nm excitation the emission peaks were found to be at 580 nm, 590 nm, 611 nm and 619 nm, corresponding to transitions at 5D0 → 7F0, 5D0 → 7F1, and 5D0 → 7F2 respectively. Because of Eu3+ inherent luminosity, these emission peaks indicate radiative transitions between excited states of ions, making them useful for developing white light-emitting phosphors for optoelectronic and flexible display applications. The 1931 CIE (x, y) chromaticity coordinates were calculated from the photoluminescence emission spectra and found to be near white light emission, indicating the potential application of the prepared phosphor for light emitting diodes (white component). TL glow curve analysis was also performed for various concentrations of doping ions and UV exposure times, and a single broad peak was observed at 187 °C. Using the computerised glow curve deconvolution (CGCD) method, kinetic parameters were computed.

Intense green light emission and thermoluminescence glow curve analysis of Tb3+ -activated CaY2 O4 phosphor.

Here, the synthesis and luminescence analysis of the Tb3+ -activated phosphor were reported. The CaY2 O4 phosphors were synthesized using a modified solid-state reaction method with a variable doping concentration of Tb3+ ion (0.1-2.5 mol%). As synthesized, the phosphor was characterized using Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction analysis techniques for the optimized concentration of doping ions. The prepared phosphor showed a cubic structure, and FTIR analysis confirmed functional group analysis. It was discovered that the intensity of 1.5 mol% was higher than at other concentrations after the photoluminescence (PL) excitation and emission spectra were recorded for different concentrations of doping ions. The excitation was monitored at 542 nm, and the emission was monitored at 237 nm. At 237 nm excitation, the emission peaks were found at 620 nm (5 D4 →7 F3 ), 582 nm (5 D4 →7 F4 ), 542 nm (5 D4 →7 F5 ), and 484 nm (5 D4 →7 F6 ). The 1931 CIE (x, y) chromaticity coordinates showed the distribution of the spectral region calculated from the PL emission spectra. The values of (x = 0.34 and y = 0.60) were very close to dark green emission. Therefore, the produced phosphor would be very useful for light-emitting diode (green component) applications. Thermoluminescence glow curve analysis for various concentrations of doping ions and various ultraviolet (UV) exposure times was carried out, and a single broad peak was found at 252°C. The computerized glow curve deconvolution method was used to obtain the related kinetic parameters. The prepared phosphor exhibited an excellent response to UV dose and could be useful for UV ray dosimetry.

Vaccine hesitancy for coronavirus SARS-CoV-2 in Varanasi India.

With the rollout of the world's largest vaccine drive for SARS-CoV-2 by the Government of India on January 16 2021, India had targeted to vaccinate its entire population by the end of 2021. Struggling with vaccine procurement and production earlier, India overcome these hurdles, but the Indian population still did not seem to be mobilizing swiftly toward vaccination centers. The severe second wave has slowed the vaccination pace and was also one of the major contributing factors to vaccine hesitancy. To understand the nature of vaccine hesitancy and its underlying factors, we conducted extensive online and offline surveys in Varanasi and adjoining regions using structured questions. Most respondents were students (0.633). However, respondents from other occupations, such as government officials (0.10), have also participated in the study. Interestingly, most people (0.75) relied on fake news and did not take COVID-19 seriously. Most importantly, we noticed that a substantial proportion of respondents (relative frequency 0.151; mean age 24.8 years) reported that they were still not interested in vaccination. We observed a significant association between vaccine hesitancy and socioeconomic status (χ2 = 307.6, p < 0.001). However, we failed to detect any association between vaccine hesitancy and gender (χ2 = 0.007, p > 0.5). People who have neither been vaccinated nor have ever been infected may become the medium for spreading the virus and creating new variants, which may lead to the vaccine-resistant variant. We expect this extensive survey to help the Government upgrade their vaccination policies for COVID-19 in North India.

White light emission and thermoluminescence studies of Dy3+ -activated hardystonite (Ca2 ZnSi2 O7 ) phosphor.

Here, we report the photoluminescence and thermoluminescent properties of Dy-activated Ca2 ZnSi2 O7 phosphors synthesized using the solid-state method. The synthesized phosphors showed hardystonite type structure, and had micron-sized particles. Fourier transform infrared spectroscopy (FTIR) showed the existence of the functional groups and confirmed the formation of phosphor and photoluminescence techniques. The phosphors under excitation at 239 nm exhibited green-yellow emission spectra in the region 481-575 nm corresponding to the 4 F9/2 →6 H15/2 and 4 F9/2 →6 H13/2 transitions of Dy3+ ions. The Commission Internationale de l'Eclairage (CIE) coordinates were achieved to be (0.25, 0.27), which was narrowly close to the white region. Thermoluminescence (TL) glow curve analysis of prepared Dy3+ -activated Ca2 ZnSi2 O7 phosphors were recorded for different ultraviolet (UV) light exposure times and found to have a linear response with dose. The TL glow curves, recorded with various UV exposure times ranging from 5 to 25 min, showed a linear response with dosage. The corresponding kinetic parameters were also calculated using a computerized glow curve deconvolution (CGCD) technique. Activation energy was observed to enhance the increase in the peak temperature and its value was substantially higher for the third peak fitted using CGCD. The obtained results indicated that the synthesized pristine phosphors could be potentially used for lighting, displays, and dosimetric applications.

Association of XRCC1, XRCC2 and XRCC3 Gene Polymorphism with Esophageal Cancer Risk.

AIM: The X-ray repair cross-complementing (XRCC) gene polymorphisms influence esophageal carcinogenesis by altering the DNA repair capacity. The present study was designed to screen five single nucleotide polymorphisms (SNPs) of XRCC genes for their susceptibility to esophageal cancer (EC) risk. There is no previous report on these polymorphisms for EC from India, where EC frequency is high. METHODS: The present study included 497 subjects (213 EC patients and 284 healthy controls). The polymorphisms were screened using the PCR-RFLP method and allele and genotype distribution were compared using chi-square test. Association analysis was done by haplotype analysis and linkage disequilibrium (LD) analysis. Gene-gene interactions were identified using multifactor dimensionality reduction (MDR). The risk was calculated using binary logistic regression. RESULTS: For XRCC1 p.Arg399Gln, a decreased risk for EC was associated with the AA genotype [OR (95% CI): 0.53 (0.3-0.95), p=0.03] even after adjusting for various covariates [OR (95% CI): 0.49 (0.26-0.9), p=0.024] and with the recessive model [OR (95% CI): 0.49 (0.27-0.8), p=0.016]. The GA genotype of p.Arg280His was associated with an increased risk for EC [OR (95% CI): 1.7 (1.0-2.82), p= 0.045] after adjustments. The two XRCC1 polymorphisms, p.Arg399Gln and p.Arg194Trp were in slight LD among EC patients (D̍́=0.845, r 2=0.042). XRCC2 and XRCC3 polymorphisms were not associated with EC risk. CONCLUSION: XRCC1 p.Arg399Gln plays a protective role in the development of the EC. The study is the first report from India, providing baseline data about genetic polymorphisms in DNA repair genes XRCC1, XRCC2 and XRCC3 modulating overall EC risk.

Porcupine gnaw marks on a Late Pliocene bone from the Upper Siwaliks exposed near Village Khetpurali (Haryana, India).

Bone accumulation by porcupines at archaeological sites is well known. However, in paleontological sites such a taphonomical occurrence is rather rare. We here report porcupine (Hystrix sp.) gnaw marks on an unidentified bone fragment, dated to ~2.6 Ma from the Upper Siwalik deposits exposed near Khetpurali (Haryana), India. The present gnaw marks are very distinct and are characterized by visible edges and grooves making clear broad and shallow furrows. The present find adds to our knowledge of Siwalik vertebrate taphonomy where most of the accumulations reported earlier were either fluvial or made by carnivores.

Study of formation of deep trapping mechanism by UV, beta and gamma irradiated Eu(3+) activated SrY2O4 and Y4Al2O9 phosphors.

This paper reports the thermoluminescence properties of Eu(3+) doped different host matrix phosphors (SrY2O4 and Y4Al2O9). The phosphor is prepared by high temperature solid state reaction method. The method is suitable for large scale production and fixed concentration of boric acid using as a flux. The prepared samples were characterized by X-ray diffraction technique and the crystallite size calculated by Scherer's formula. The prepared phosphor characterized by Scanning Electron Microscopic (SEM), Fourier Transform Infrared (FTIR), Energy Dispersive X-ray analysis (EDX), thermoluminescence (TL) and Transmission Electron Microscopic (TEM) techniques. The prepared phosphors for different concentration of Eu(3+) ions were examined by TL glow curve for UV, beta and gamma irradiation. The UV 254nm source used for UV irradiation, Sr(90) source was used for beta irradiation and Co(60) source used for gamma irradiation. SrY2O4:Eu(3+)and Y4Al2O9:Eu(3+) phosphors which shows both higher temperature peaks and lower temperature peaks for UV, beta and gamma irradiation. Here UV irradiated sample shows the formation of shallow trap (surface trapping) and the gamma irradiated sample shows the formation of deep trapping. The estimation of trap formation was evaluated by knowledge of trapping parameters. The trapping parameters such as activation energy, order of kinetics and frequency factor were calculated by peak shape method. Here most of the peak shows second order of kinetics. The effect of gamma, beta and UV exposure on TL studies was also examined and it shows linear response with dose which indicate that the samples may be useful for TL dosimetry. Formation of deep trapping mechanism by UV, beta and gamma irradiated Eu(3+) activated SrY2O4 and Y4Al2O9 phosphors is discussed in this paper.

White Light Emission by Dy3+ Doped Phosphor Matrices: A Short Review.

In this review we have studied number of research papers related to white light emission from Dy3+ doped different host matrices. It is observed that most of the Dy3+doped aluminates, silicates, borates etc., emitted blue, green and red colour with specific intensities so that CIE coordinates, appeared near to white light. Correlated Colour Temperature(CCT) values of these phosphors expressed that the white light emission produced, was adaptable to human eyes. Dy3+ ions act as activator in each case. Four peaks at approximately 480,575, 670, and 757 nm could be seen in most of the Dy3+ doped phosphors. Expected transition responsible for these peaks are 4F9/2 → 6H15/2 (Blue Colour), 4F9/2 → 6H13/2 (Green-Yellow Colour), 4F9/2 → 6H11/2 (Red Colour) and 4F9/2 → 6H9/2(Brownish Red Colour). Few of the discussed phosphors exhibited long phosphorescence, starting from several minutes to few hours. Mechanism responsible for long lasting white light emission was also discussed. Five different factors, to recognize the phosphors for its suitability as commercial white light phosphor have been discussed.

L-asparaginase: an effective agent in the treatment of acute lymphoblastic leukemia.

L-asparaginase (L-ASNase) is an enzyme used most effectively in the treatment of acute lymphoblastic leukemia (ALL) for more than 30 years. It catalyzes the hydrolysis of amino acid l-asparagine to aspartic acid and ammonia, which leads to cell death. Clinical trials have been conducted using L-ASNase in combination with other drugs and radiotherapy, which have led to great success in the treatment of ALL. Treatments consist of induction therapy and central nervous system therapy. The achievement of complete remission in patients is associated with a few side-effects of using L-asparaginase, including pancreatitis, coagulation abnormalities and allergic reactions. Sometimes tumor cells may develop resistance to L-ASNase. To overcome these difficulties, the drug is modified by pegylation or immobilization, and also treatment protocols can be modified to increase the efficiency of the drug.