Multicolor tunable bright photoluminescence in Ca2+/Mg2+ modified Eu3+ doped ZnGa2O4 phosphors under UV excitation for solid state lighting applications.

The Eu3+ doped and Mg2+/Ca2+ co-doped ZnGa2O4 phosphor samples were synthesized by solid-state reaction method and their structural and optical properties studied. The phase, crystallinity and particles size of the phosphor samples were studied by XRD and SEM measurements. EDS analyses were used to identify the elements present in the phosphor materials. The vibrational groups present in the phosphor samples were examined by Fourier transform infrared (FTIR) measurements. Pure ZnGa2O4 emits intense blue light under 260 nm excitation. However, Eu3+ doped and Mg2+/Ca2+ co-doped ZnGa2O4 phosphor samples exhibit intense red emission under 393 nm excitation. A bluish white color is observed in these samples under 290 nm excitation. The maximum PL emission intensity is found at 0.1 mol% Eu3+ doping concentration. For higher concentrations, concentration quenching was observed due to dipole-dipole interaction. The emission intensity is enhanced upto 1.20 and 2.91 times on co-doping of Mg2+ and Ca2+via induced crystal field due to charge imbalance. The emission intensity of the phosphor is found to enhance further on annealing the samples at 873 K. Under various excitation wavelengths, color tunability was seen from blue to bluish-white to red regions. The lifetime of the 5D0 level of the Eu3+ ion improves via doping of Mg2+/Ca2+ ions and it increases appreciably on annealing. The temperature dependent photoluminescence study (TDPL) reveals a thermal quenching behavior of the sample with thermal stability ∼65% and activation energy ∼0.223 eV in the Eu3+/Ca2+ co-doped ZnGa2O4 phosphor sample.

Enhanced upconversion emission of Er3+/Yb3+ and Er3+/Yb3+/Zn2+ doped calcium aluminate for use in optical thermometry and laser induced optical heating.

There are two key factors to design an efficient green upconversion (UC) emission based optical sensor for temperature. The primary need is to develop a thermally stable and economical material, for a stable sensor, and the second essence is to get an efficient green UC emission, for high sensitivity of the sensor. The proof of this concept is demonstrated on a model system CaAl2O4: Er3+, co-doped with Yb3+ and Zn2+. UC emission of Er3+ ion is enhanced, primarily, through co-operative energy transfer from Yb3+ to Er3+ ions. Secondly, we prove that, incorporation of Zn2+ ions alters local crystal field environment around Er3+ ions which causes an enhancement in green UC emission. The variation in intensity ratio of 2H11/2 â†’ 4I15/2 (green) and 4S3/2 â†’ 4I15/2 (green) transitions with temperature is studied to report the sensing property. We show that, sensitivity becomes better with an increase in UC efficiency and the best sensitivity is attained for CaAl(0.793)2Er0.007Yb0.05Zn0.15O4 sample, ∼0.0154 K-1 at 308 K. The obtained result is compared with other works and implies its better suitability. Further, the laser induced optical heating is also observed. The laser induced optical heating has been observed experimentally at 400 K above 1 W laser power. This has been further verified by theoretical justification of heating at various pump powers.

Effect of the concentration of the dopants (Er3+, Yb3+ and Zn2+) and temperature on the upconversion emission behavior of Er3+/Yb3+ co-doped SrAl2O4 phosphor.

Er3+/Yb3+ co-doped SrAl2O4 (SRA: Er3+, Yb3+) phosphor has been synthesized by high temperature solid state reaction technique. The pure phase formation has been confirmed by X-ray diffraction (XRD) measurements. The surface morphology is studied by scanning electron microscopy (SEM) technique. The FTIR measurements give the information of vibrational bands arising due to sample. The intense UC emission from SRA: Er3+, Yb3+ phosphor has been monitored on excitation with 980nm diode laser. The SRA: Er3+, Yb3+ samples prepared at 1473K show a dominant green emission. On the other hand it shows dominant red emission when the sample is heated to 1623K. Variation of concentration of Er3+ and Yb3+ ions in SRA: Er3+, Yb3+ phosphor suggests two possible mechanisms involved in UC emission process viz. cross relaxation (CR) process and energy back transfer (EBT) process, respectively. The cross relaxation mechanism seems to play a major role. The UC emission efficiency is enhanced several times on co-doping of Zn2+ ion replacing Al3+ or Sr2+ in SRA: Er3+, Yb3+ phosphor sample. The color of the UC emission can be tuned from green to red region by varying the concentration of zinc.

Role of anti-tubercular treatment for positive endometrial aspirate DNA-PCR reproductive outcome in infertile patients in Indian setting - A randomized trial.

AIMS: The aim of the study was to determine the effect of anti-tubercular therapy (ATT) versus no ATT on reproductive outcome in patients with positive endometrial aspirate DNA-PCR for tuberculosis. SETTINGS AND DESIGN: Department of Obstetrics and Gynecology in collaboration with the Department of Microbiology at the All India Institute of Medical Sciences, New Delhi, India. METHODS AND MATERIALS: This prospective randomized study was conducted on 100 women in the reproductive age group with primary or secondary infertility, attending the Gynecology OPD at AIIMS. Women with positive endometrial DNA-PCR, patent tubes on laparoscopy, and all other tests being negative for genital TB were randomized into two groups. In Group 1, patients received ATT for 6 months while in Group 2, patients were not given ATT. In patients who did not conceive a repeat endometrial sampling for DNA-PCR was performed at 6 months and 12 months post-laparoscopy. STATISTICAL ANALYSIS: It was carried out using Stata 11.0 (College Station, TX, USA). RESULTS: In Group 1 (ATT), 25 women achieved pregnancy with a pregnancy rate of 50% while in Group 2 (no ATT), 21 women achieved pregnancy with a pregnancy rate of 42% and the difference (95% CI) was 8.0% (-11.5%, 27.5%) which was not statistically significant (p=0.422). Difference (95% CI) in the rate of repeat EA DNA-PCR being positive between the two groups at 6 months was 3.1% (-2.9%, 9.1%), p=0.299, while at the end of 12 months, repeat DNA-PCR remained positive in 23 patients in Group 1 and in 26 patients in Group 2. Difference (95% CI) in the rate of repeat EA DNA-PCR being positive between the two groups at 12 months was 2.3% (-13.0%, 17.7%), p=0.767. CONCLUSION: The present study does not validate ATT for positive DNA-PCR; however, it does provide an evidence to stop over-treating patients on the basis of positive EA DNA-PCR even after they have received a 6 months course of ATT. Repeating PCR at 6 months and at 12 months has no role and ATT should not be repeatedly given to the patient on the basis of repeat DNA-PCR alone. CLINICAL TRIAL REGISTRATION NUMBER: CTRI/2015/10/006235, www.ctri.nic.in.

Disc battery ingestion; a single event with different outcomes.

Foreign body (FB) ingestion is a common problem especially in children below the age of 5 years. This is fueled by their curiosity to explore their surroundings. The ingested foreign body finds its way out of the gastrointestinal tract without any serious consequences most of the time. On the other hand, disc battery ingestion has been reported to cause serious harm when ingested including death. We report two patients who had ingested disc batteries and their respective outcomes.

Infrared to infrared upconversion emission in Pr(3+)/Yb(3+) co-doped La2O3 and La(OH)3 nano-phosphors: a comparative study.

The Pr(3+)/Yb(3+) co-doped La2O3 and La(OH)3 nano-phosphors have been synthesized through solution combustion method. The structure and morphology of the samples have been studied using X-ray diffraction (XRD) and transmission electron microscopy (TEM). The physical and optical properties of the samples have been measured and compared. A broad intense infrared emission centered at 850nm due to (1)I6→(1)G4 transition along with sharp green emission centerd at 513nm due to (3)P0→(3)H4 transition are observed on excitation with 976nm laser. The emission intensity of Pr(3+) is optimized with concentration and it is maximum at 0.08mol%. The annealed samples are found to be more crystalline and emit larger photoluminescence due to removal of quenching centers. The power dependent study of green upconversion emission indicates the involvement of two photons. The phosphor in La(OH)3 phase is more stable though the photoluminescence emission is slightly weak. La(OH)3 is less toxic compared to La2O3 and is biocompatible. It generates more heat and can be used in biothermal treatment.

Structural characterizations and intense green upconversion emission in Yb3+, Pr3+ co-doped Y2O3 nano-phosphor.

We report the structural and optical properties of Yb(3+), Pr(3+) co-doped Y2O3 nano-phosphor synthesized through solution combustion method. The structural studies reveal the nano-crystalline structure of the sample. The energy dispersive spectroscopy (EDS) measurements confirm the presence of Y, O, Pr and Yb elements in the sample. Fourier transform infrared studies show the vibrational features of the samples. The fluorescence spectra of the samples have been monitored on excitation with 976 nm and the intense green upconversion emission observed at 552 nm is due to (3)P0→(3)H5 electronic transition. The concentration of Pr(3+) ion in the sample is optimized and the fluorescence intensity is maximum at 0.08 mol% of Pr(3+). The power dependence studies reveal the involvement of two photons in the emission process. The possible mechanism of upconversion has been discussed on the basis of schematic energy level diagram. The sample annealed at higher temperature enhances the fluorescence intensity up to 8 times and this enhancement is discussed in terms of the removal of optical quenching centers. The nano-phosphor can be applicable in the field of display devices and green laser.

Enhanced luminescence and energy transfer study in Tb:Sm codoped lead fluorotellurite glass.

Spectroscopic properties of Sm(3+), Tb(3+) doped and Tb(3+):Sm(3+) co-doped lead fluorotellurite glasses have been studied in detail. On the excitation with 355 and 532 nm laser wavelengths, the luminescence properties of the singly and doubly doped glasses have been analyzed. Intensity of characteristic emission bands due to Sm(3+) ions is appreciably enhanced in the presence of Tb(3+) ions. This is due to the energy transfer from Tb(3+) to Sm(3+) ions. Different energy transfer parameters have also been calculated, which affirm an efficient energy transfer from Tb(3+) to Sm(3+) ions.

Optical properties of cerium doped oxyfluoroborate glass.

Cerium doped oxyfluoroborate glasses have been prepared and its spectroscopic properties have been discussed. It is found that the absorption edge shifts towards the lower energy side for the higher concentration of cerium dopant. Optical band gap for these glasses have been calculated and it is found that the number of non-bridging oxygen increases with cerium content. The emission spectra of these glasses have been recorded using UV laser radiations (266 and 355 nm) and it is observed that these glasses show bright blue emission. On the basis of excitation and emission spectra we have reported the existence of at least two different emission centers of Ce(3+)ions.

Behavioural and histopathological effects of azodye on kidney and gills of Labeo rohita fingerlings.

The present paper emphasizes on the histopathological effects of an azo dye, Direct Green 6 on the kidney and gills of Labeo rohita by light microscopy. Fingerlings were exposed to sublethal concentrations (2.5, 5.0 and 10.0 ppm) of dye for 5, 10 and 15 days to study histopathological changes. No histopathological changes were seen in the kidney and gills of control fingerlings. Unlike control fingerlings, both the target organs showed some histopathological changes. Fingerlings exposed to 2.5 ppm concentration of the dye showed shrinkage of glomerulus, increased peritubular space, decreased lumen while 5.0 ppm produced haemorrhage in the interstitial tissue and mild degeneration in the kidney. Necrosis in the tubular epithelium, distruction of cell membrane and loss of cellular cytoplasm were observed in kidney of fingerlings exposed to 10 ppm dye concentration. Gills of fingerlings exposed to 2.5 ppm of dye showed aneurism and mild degenerated central axis. 5 ppm of dye concentration produced remarkable changes like epithelial lifting, hyperplasia, enlarged and vacuolated cartilage cells. Haemorrhagic tip, fusion and curling of secondary gill lamellae and at some places complete removal of them were also observed in gills of fingerlings exposed to 10 ppm.

A review of the HIV-infected homeless sub-population at the Centre for HIV/AIDS Research, Education and Services, Department of Medicine, University Hospital of the West Indies.

OBJECTIVE: The twin epidemics of HIV and homelessness present several challenging aspects to the development of programmes for the provision of treatment and care. This paper describes the characteristics of this population being managed by a collaborative effort between the Centre for HIV/AIDS Research, Education and Services, Department of Medicine, University Hospital of the West Indies and the National Council on Drug Abuse. SUBJECTS AND METHODS: A retrospective descriptive study was conducted via review of patients'medical files. Demographic and clinical data of the HIV-infected homeless population were summarized, highlighting issues related to the provision of care, rates of antiretroviral therapy (ART) uptake and subsequent adherence to treatment and known factors associated with HIV transmission. RESULTS: A total of 12 cases were included in the analysis. There was an average age of 38.0 years (IQR 32.5-49.25) with the majority being female, nine (75.0%). Late stage diagnosis was a common feature. The majority of cases were eligible for ART on first contact, with CD4 counts on average being 284.4 (95% CI 10.9.0, 459.8). Significant risk factors for HIV transmission were also identified as all cases reported being sexual active with limited condom use reported and high reported numbers of lifetime partners, 30 (IQR 25.0-100.0). Other factors identified include eight (66.6%) cases reporting sexually transmitted infection (STI) symptoms, 10 (83.3%) reporting substance abuse and nine (75.0%) reporting sex work. CONCLUSION: The implementation of combination interventions providing a comprehensive package of services that address the multitude of issues facing the HIV-infected homeless population is required in order to appropriately manage this population.

A review of the HIV-infected homeless sub-population at the Centre for HIV/AIDS Research, Education and Services, Department of Medicine, University Hospital of the West Indies / Una revisión de la subpoblación sin hogar de infectados por el VIH en el Centro para la Investigación, Educación y Servicios del VIH/SIDA, del Departamento de Medicina del Hospital Universitario de West Indies

OBJECTIVE: The twin epidemics of HIV and homelessness present several challenging aspects to the development of programmes for the provision of treatment and care. This paper describes the characteristics of this population being managed by a collaborative effort between the Centre for HIV/AIDS Research, Education and Services, Department of Medicine, University Hospital of the West Indies and the National Council on Drug Abuse. SUBJECTS AND METHODS: A retrospective descriptive study was conducted via review of patients'medical files. Demographic and clinical data of the HIV-infected homeless population were summarized, highlighting issues related to the provision of care, rates of antiretroviral therapy (ART) uptake and subsequent adherence to treatment and known factors associated with HIV transmission. RESULTS: A total of 12 cases were included in the analysis. There was an average age of 38.0 years (IQR 32.5-49.25) with the majority being female, nine (75.0%). Late stage diagnosis was a common feature. The majority of cases were eligible for ART on first contact, with CD4 counts on average being 284.4 (95% CI 10.9.0, 459.8). Significant risk factors for HIV transmission were also identified as all cases reported being sexual active with limited condom use reported and high reported numbers of lifetime partners, 30 (IQR 25.0-100.0). Other factors identified include eight (66.6%) cases reporting sexually transmitted infection (STI) symptoms, 10 (83.3%) reporting substance abuse and nine (75.0%) reporting sex work. CONCLUSION: The implementation of combination interventions providing a comprehensive package of services that address the multitude of issues facing the HIV-infected homeless population is required in order to appropriately manage this population.

OBJETIVO: Las epidemias gemelas del VIH y las personas sin hogar, presentan varios aspectos desafiantes para el desarrollo de programas que ofrecen atención y tratamiento. Este trabajo describe las características de esta población, y su manejo como parte de un esfuerzo de colaboración entre el Centro para la investigación, educación y servicios del VIH/SIDA, del Departamento de Medicina del Hospital Universitario de West Indies, y el Consejo Nacional para el Abuso de Drogas. SUJETOS Y MÉTODOS: Se realizó un estudio descriptivo retrospectivo mediante revisión de expedientes médicos de los pacientes. Se resumieron los datos clínicos y demográficos de la población sin hogar infectada por el VIH, destacando las cuestiones relacionadas con la prestación de asistencia, las tasas de adopción de terapia antirretroviral (TAR), y la posterior adherencia al tratamiento, además de factores conocidos, asociados con la transmisión del VIH. RESULTADOS: Un total de 12 casos se incluyeron en el análisis. La edad promedio fue de 38.0 años (IQR 32.5-49.25), siendo mujeres la mayoría, 9 (75.0%). El diagnóstico en etapa tardía fue una característica común. La mayoría de los casos fueron elegibles para TAR desde el primer contacto, con conteos CD4 de 284.4 (95% CI 10.9.0, 459.8) como promedio. También se identificaron factores de riesgo significativos para la transmisión del VIH, ya que todos los casos reportaron actividad sexual con un uso limitado de condón, y un gran número de parejas sexuales durante toda la vida, 30 (IQR 25.0-100.0). Otros factores identificados incluyen 8 (66,6%) casos que reportaron síntomas de infección de transmisión sexual (ITS), 10 (83,3%) que reportaron abuso de sustancias, y 9 (75.0%) que reportaron trabajo sexual. CONCLUSIÓN: Se requiere la implementación de intervenciones de combinación que ofrezcan un paquete integral de servicios que respondan a los numerosos problemas que enfrenta la población sin hogar infectada por VIH, a fin de tratar adecuadamente a esta población.

Structural and spectroscopic diagnosis of Eu:ZnO and Eu:Yb:ZnO glass and ceramics.

Eu and Eu:Yb codoped ZnO nanocrystals embedded in B(2)O(3) glass matrix were synthesized and their structural, optical properties were discussed. On excitation with 532 nm laser radiation intense orange/red emissions from Eu(3+) ions were observed. The fluorescence intensity was found to enhance on annealing. Frequency upconversion emissions from Eu(3+) ions were observed in presence of Yb(3+) ions on excitation with NIR (976 nm) laser. The enhancement in emission intensity was explained and the photo-physics involved is linked with the unique structural properties of the crystallites formed. Ion interactions and the different energy transfer parameters were also calculated.

A study on presentation and behavior of colo-rectal carcinoma in young Indian patients.

BACKGROUND: Colorectal cancer is rare in younger age group. Most cases occur in the second decade of life and are clinically aggressive. The prognosis of these patients is generally poor. This is a retrospective study in which data of Indian patients was compared to standard literature. METHODS: Data on 32 young patients with colorectal cancer between ages of 10-25 years treated between January 2000 and December 2006 was reviewed. Clinical presentation, natural history and response to therapy were evaluated. RESULTS: Studied cases comprised 9.9% of the total number of colorectal cancer patients. The median age of presentation was 21.5 years. Four-fifths of the cases presented in late stage. Nodal involvement was seen in 38% cases and metastatic disease in 12% cases. The rectum was the most commonly involved site. A majority of the patients presented with pain (81%), altered bowel habits (72%) and bleeding per rectum (78%). Surgery was done in 16 cases; radiotherapy in 16 patients; while chemotherapy was used in 19 cases. Responses at completion of treatment were seen in 28% cases; while 1 year post treatment only 12% cases were alive and only 6% at 2 years. CONCLUSIONS: Colorectal cancer in younger age is rare and a high level of suspicion is necessary to diagnose it at an early and curable stage. Rectal bleeding therefore should not be ignored but evaluated further with at least a digital rectal examination and a sigmoidoscopy. Failure to do so results in late presentation with consequent dismal survival rates.

Effect of surfactants on phosphatase level of fresh water fish Labeo rohita.

Alterations in the activity of enzymes Acid phosphatase (E.C.3.1.3.2) and Alkaline phosphatase (EC 3.1.3.1) in organs such as liver, gills and muscle of rohu following its exposure to surfactants viz. CTAB, SDS and Triton X-100 were analyzed. Different levels of exposure were given depending on the LC50 value of the surfactant used. Also, the influence of age and weight of the organisms was tested simultaneously. The activity of ACP in the tissues of fish exposed to all the three surfactants showed marked enhancement after exposure; the effect being highest in the liver followed by gill and muscle. Activity levels of ALP in different tissues of the fish exposed to the surfactants also showed an increase. Maximum increase was found in the liver followed by muscle, and gill. The increase in the levels of these enzymes indicates a stressful condition of the fish.

A retrospective study of 18 cases of adenoid cystic cancer at a tertiary care centre in Delhi.

CONTEXT: Adenoid cystic carcinoma (ACC) is a rare neoplasm that usually arises from the salivary, lacrimal, or other exocrine glands. It is characteristically locally infiltrative in nature and has a tendency toward local recurrence, high propensity for perineural invasion, and prolonged clinical course. AIM: To analyze the presentation and natural history of cases of adenoid cystic tumors of salivary glands in our institution; and to compare with the existing literature. DESIGN AND SETTING: Retrospective study at the Department of Radiotherapy. MATERIALS AND METHODS: Data on 18 patients of ACC of the salivary glands treated between 2004 and 2008 were reviewed with respect to clinical presentation, stage, and histology. RESULTS: There were 8 cases of major salivary gland tumors (47%), of which 2 were in the submandibular and 6 were involving the parotid. Ten patients (53%) had minor salivary gland involvement. Two patients had metastasis at the time of presentation. All patients underwent surgery. Radiotherapy was delivered to 16 patients and chemotherapy to 6 patients (concurrent, n = 3 and adjuvant, n = 3) and no adjuvant therapy was given to 2 patients. All patients were alive at a median follow-up of 3 years. No patient developed local or distant failure during the study duration. CONCLUSION: ACC has locally aggressive behavior. Radiotherapy adjuvant to surgery improves local control in locally advanced disease. Longer follow-up is mandatory in view of incidence of late metastasis.