Luminescence studies in KMgF(3):Eu,Ag

A new sensitive material KM(g)F(3):Eu,Ag has been developed with double dopants europium (Eu) and silver (Ag) by melting equal molecular proportions or KF and MgF(2) along with dopants (0.2 mol % each) in argon atmosphere. Luminescence studies have been carried out in this material to check its possible use in radiation dosmetry applications. Thermoluminescence (TL) studies in this material show that its TL sensitivity is three times that of the existing tissue equivalent material LiF:Mg,Ti (TLD- 100), while KMgF(3) doped with Eu alone and Ag alone shows sensitivities equal to that of TLD-100. KMgF(3):Eu,Ag shows a major TL peak around NOT unlike TLD-100 which has a complicated glow curve shape. The TL emission spectra of gamma irradiated material show characteristic emission of Eu(2+). Compared to KMgF(3):Eu, the emission intensity of Eu has been found more in KMgF(3):Eu,Ag. Photoluminescence studies show that there is no conversion of Eu(2+) to Eu(3+) on gamma irradiation. Electron spin resonance (ESR) studies have been carried out in this material to check if there is any valance conversion of Eu and Ag. Both the irradiated as well as unirradiated materials show signal for Eu(2+) ion did not show my signal to for Ag(2+) ion. Hence, in the presence of Ag(+) more Eu(2+) is entering into the crystal lattice which enhances the luminescence efficiency

An extensive investigation on nucleation, growth parameters, crystalline perfection, spectroscopy, thermal, optical, microhardness, dielectric and SHG studies on potential NLO crystal - Ammonium Hydrogen L-tartarte

Ammonium Hydrogen L-tartarte (AMT), an organic nonlinear optical crystal was grown by slow evaporation method at ambient temperature. Solubility, metastable zone width and induction period of Ammonium Hydrogen L-tartarte in aqueous solution were determined. Good quality crystals were selected and characterized by Single crystal XRD, HR-XRD, FT-IR, H-1 NMR, Mass, TGA-DTA, SEM, EDAX, optical and NLO studies. Single crystal XRD analysis revealed that the crystal system belongs to orthorhombic with cell parameters a = 7.65 angstrom, b = 7.85 angstrom and c = 11.07 angstrom. High-resolution-X-ray diffraction (HR-XRD) analysis was carried out to study the crystalline perfection of the grown crystal. H-1 NMR and FTIR spectrum thus confirmed the presence of functional groups of the grown crystal. Molecular mass of AMT was measured accurately by mass spectroscopic analysis. Surface features of the grown crystal were analyzed by SEM, AFM, chemical etching and the presence of elements in the compound was identified by EDAX analysis. Thermal behavior of the grown crystal has been studied by TG/DTA analysis. The recorded UV-Vis-NIR spectrum shows excellent transmission in the region of 190-1100 nm. The Vickers and Knoop's microhardness studies have been carried out on AMT crystals over a range of 10-50 g. Hardness anisotropy has been observed in accordance with the orientation of the crystal. Fluorescence spectral studies were carried in the range of 280-500 nm for the grown crystal. The SHG conversion efficiency and laser damage threshold were measured using an Nd: YAG laser (1064 nm)

Enhancement of structural perfection of alkali halide single crystals by doping with copper

The pure and copper (Cu+) doped alkali halide single crystals have been grown from melt by using the Czochralski (Cz) method. The optical absorption studies confirm that the doped copper is incorporated with the grown crystals. The effect of doping on crystalline perfection of grown crystals was analyzed by high resolution X-ray diffraction (HRXRD) measurements. The HRXRD results clearly reveal that the Cu+ doped crystals are having higher crystalline perfection than pure crystals. The mechanical behavior of the grown crystals was measured by the Vickers microhardness measurement. The hardness value of the crystals increases with an increase in load and thereafter it becomes independent of the applied load. The Meyer index number and hardness using Hays-Kendall approach of pure and doped crystals were calculated and tabulated

Luminescence studies in KMgF₃:Eu,Ag

459-460A new sensitive material KMgF3:Eu,Ag has been developed with double dopants europium (Eu) and silver (Ag) by melting equal molecular proportions of KF and MgF2 along with dopants (0.2 mol % each) in argon atmosphere. Luminescence studies have been carried out in this material to check its possible use in radiation dosimetry applications. Thermoluminescence (TL) studies in this material show that its TL sensitivity is three times that of the existing tissue equivalent material LiF:Mg,Ti (TLD-100), while KMgF3 doped with Eu alone and Ag alone shows sensitivities equal to that of TLD-100. KMgF3:Eu,Ag shows a major TL peak around 240oC unlike TLD-100 which has a complicated glow curve shape. The TL emission spectra of gamma irradiated material show characteristic emission of Eu2+. Compared to KMgF3:Eu, the emission intensity of Eu has been found more in KMgF3:Eu,Ag. Photoluminescence studies show that there is no conversion of Eu2+to Eu3+ on gamma irradiation. Electron spin resonance (ESR) studies have been carried out in this material to check if there is any valance conversion of Eu and Ag. Both the irradiated as well as unirradiated materials show signal for Eu2+ ion and did not show any signal for Ag2+ ion. Hence, in the presence of Ag+ more Eu2+ is entering into the crystal lattice which enhances the luminescence efficiency

Multivariate analysis in large cardamom (Amomum subulatum Roxb.)

The variability in large cardamom (Amomum subulatum) germplasm was studied by applica-tion of multivariate methods such as principal component analysis, discriminant functionanalysis and Hotelling’s T2 statistic. Variables such as girth of the clump, number of bearingtillers, number of spikes clump-1, number of capsules spike-1, capsule length, capsule diam-eter and capsule weight recorded in 40 accessions belonging to two cultivars of large carda-mom namely, Ramsey and Sawney were used in the study. Principal component analysis re-sulted in the identification of three components, which could explain 73% of variability inlarge cardamom. Discriminant function analysis brought about a discriminant function todistinguish between the two cultivars of large cardamom. Among the variables, capsuleweight, girth of the clump, capsules spike-1 and number of bearing tillers contributed maxi-mum towards yield and hence such characters can be effectively exploited in crop improve-ment programmes. &nbsp

Optical-absorption studies of ion-implantation damage in Si on sapphire

A detailed study of the implantation-induced damage in Si on sapphire, carried out by optical-absorption measurements extending from energies above the band gap down to energies far into the subgap region of Si, is presented. The changes induced in the optical band gap, band-edge slopes, and in the subgap features of the spectra are carefully described. The various stages of formation and quenching of divacancies were monitored as a function of implantation conditions and annealing cycles through their 1.8-m absorption band. It is shown that the divacancies strongly affect the population of band-tail states and the annealing studies revealed that the progressive quenching of the divacancy band is followed by the appearance of another absorption band, characteristic of some intrinsic secondary defect, whose annealing behavior is similar to the one observed for the five-vacancy electron-paramagnetic-resonance spectrum. The study of the structural relaxation process in implanted a-Si gave indications that the process is indeed associated with annihilation of defects as well as average strain reduction in the material, in agreement with earlier indications. Finally, some common features, such as band-edge inverse-logarithmic slope values and subgap features, are found in annealed implanted crystalline and a-Si. © 1994 The American Physical Society

Optical absorption studies of ion implanted and amorphous silicon

A detailed study of the implantation induced damage in Si on sapphire, carried out by optical absorption measurements extending from energies above the band gap down to energies far into the sub gap region of Si, is presented. The changes induced in the optical band gap, band edge slopes and in the sub gap features of the spectra are carefully described. The various stages of formation and quenching of divacancies were monitored as a function of implantation conditions and annealing cycles through their 1.8 μm absorption band. It is shown that the divacancies strongly affect the population of band tail states and the annealing studies revealed that the progressive quenching of the divacancy band is followed by the appearance of another absorption band, characteristic of some intrinsic secondary defect, whose annealing behaviour is similar to the one observed for the 5-vacancies EPR spectrum. The study of the structural relaxation process in implanted a-Si gave indications that the process is indeed associated with annihilation of defects as well as average strain reduction in the material, in agreement with earlier indications

Optical absorption studies of ion implanted and amorphous silicon

A detailed study of the implantation induced damage in Si on sapphire, carried out by optical absorption measurements extending from energies above the band gap down to energies far into the sub gap region of Si, is presented. The changes induced in the optical band gap, band edge slopes and in the sub gap features of the spectra are carefully described. The various stages of formation and quenching of divacancies were monitored as a function of implantation conditions and annealing cycles through their 1.8 µm absorption band. It is shown that the divacancies strongly affect the population of band tail states and the annealing studies revealed that the progressive quenching of the divacancy band is followed by the appearance of another absorption band, characteristic of some intrinsic secondary defect, whose annealing behaviour is similar to the one observed for the 5-vacancies EPR spectrum. The study of the structural relaxation process in implanted a-Si gave indications that the process is indeed associated with annihilation of defects as well as average strain reduction in the material, in agreement with earlier indications

P–016 Using artificial intelligence to predict semen upgrading after microsurgical varicocele repair

Abstract Study question Can we use artificial intelligence models to predict semen upgrading after microsurgical varicocele repair? Summary answer A machine learning model performed well in predicting clinically meaningful post-varicocelectomy semen upgrade using pre-operative hormonal, clinical, and semen analysis data. What is known already Varicocele repair is recommended in the presence of a clinical varicocele together with at least one abnormal semen parameter, and male infertility. Unfortunately, up to 50% of men who meet criteria for repair will not see meaningful benefit in outcomes despite successful surgery. Nomograms exist to help predict success, but these are based out of single-center databases, do not incorporate hormonal data, and are rarely designed to predict pre-defined, clinically meaningful improvements in semen parameters. Study design, size, duration Data were collected from an international, multi-center retrospective cohort. A total of 240 men were identified. Data from 160 men from Miami, USA and 80 men from Toronto, Canada were included. Data was collected from 2006 to 2020. Participants/materials, setting, methods We collected pre and postoperative clinical data following varicocele surgery. Clinical upgrading was defined as an increase in sperm concentration that would allow a couple to access new reproductive technologies/techniques. The tiers used for upgrading were 0–1million/cc (Intracytoplasmic Sperm Injection), 1–5 million (In Vitro Fertilization), 5–15 million (Intrauterine Insemination), and >15 million (Natural conception). Artificial intelligence models were trained and tested using R to predict which patients upgraded after surgery. Main results and the role of chance 51% of men underwent bilateral varicocele repair. The majority of men had grade 2 varicocele on the left, and (when present) a grade 1 varicocele on the right. Overall, 47% of men experienced an upgrade following varicocele surgery, 47% did not change, and 6% downgraded. The data from Miami were used to create a random forest model for predicting clinically significant upgrade in sperm concentration. The most informative model parameters were preoperative FSH, sperm concentration, and surgical laterality. The model identified three clinical categories: men with unfavorable, intermediate, and favorable features to predict varicocele upgrade. On external validation using data from Toronto, the model accurately predicted upgrade in 87% of men with favorable features, and in 49% and 36% of men with intermediate and unfavorable features, respectively. Overall, the model performed well on external validation with an AUC of 0.72 and good calibration. Calibration plots, using cross-validation, define how well the predicted probabilities match the actual probability of sperm concentration upgrade. The random forest model was run twelve times. All model characteristics are the mean of ten model runs with the highest and lowest performing runs removed. The model was translated to an online calculator that can be used by clinicians. Limitations, reasons for caution One limitation to our study is that we were not able to predict total motile sperm count (TMSC), which has been shown to perform slightly better than concentration at predicting assisted reproduction outcomes. By focusing on clinically significant upgrading, this difference should be minimized. Wider implications of the findings: Predicting the chances of clinically significant semen upgrading after varicocele repair is essential for patients and clinicians to understand. Several men undergo surgery with no subsequent benefit, which may lead to a delay in definitive treatment with IVF/IUI. Understanding their chances will help couples make better informed decisions moving forward. Trial registration number Not applicabl