Improvement in white light emission of Dy3+doped CaMoO4via Zn2+co-doping.

The research in developing a single ingredient phosphor for white-light emission is progressively increasing. It is well known that the4F9/2 â†’ 6H13/2(yellow) and4F9/2 â†’ 6H15/2(blue) transitions of Dy3+ions give near-white light emission. The white light emission of Dy3+ions can be enhanced via improving the crystallinity of the host phosphor via co-doping of transition metal ions. In this paper, we report a significant improvement in the white light emission of Dy3+doped CaMoO4by co-doping Zn2+ions. The x-ray diffraction pattern confirms the tetragonal phase of pure and doped CaMoO4phosphor. The peak broadening and a red-shift in the absorption peak are observed by UV-vis absorption analysis of Zn2+/Dy3+doped CaMoO4. From Photoluminescence studies, we have observed that in Dy3+doped CaMoO4, the 4% Dy3+doped CaMoO4exhibits maximum emission. The Zn2+ions are co-doped to further increase the luminescence intensity of CaMoO4:4%Dy3+and the maximum luminescence is obtained for 0.25% Zn2+concentration. Two intense emission peaks centered at 484 nm and 574 nm related to transitions4F9/2 â†’ 6H15/2and4F9/2 â†’ 6H13/2of Dy3+ion are observed for Dy3+doped phosphor. The4F9/2 â†’ 6H13/2transition is the forced electric dipole transition which is affected by its chemical environment. After Zn2+co-doping, the4F9/2 â†’ 6H13/2transition is affected due to a change in asymmetricity around the Dy3+ions. The 0.25% co-doping of Zn2+gives 34% enhancement in luminescence emission of 4% Dy3+doped CaMoO4. As a result, the CIE coordinates of chromaticity diagram and the color purity of the 0.25% Zn2+co-doped CaMoO4:4Dy3+show improvement in the overall white light emission. We have shown that with Zn2+co-doping, the non-radiative relaxations are reduced which results in improved white light emission of Dy3+ions.

Strain assisted magnetoelectric coupling in ordered nanomagnets of CoFe2O4/SrRuO3/(Pb(Mg1/3Nb2/3)O3-PbTiO3) heterostructures.

We have explored the electric field controlled magnetization in the nanodot CoFe2O4/SrRuO3/PMN-PT (CFO/SRO/PMN-PT) heterostructures. Ordered ferromagnetic CFO nanodots (∼300 nm lateral dimension) are developed on the PMN-PT substrate (ferroelectric as well as piezoelectric) using a nanostencil-mask pattering method during pulsed laser deposition. The nanostructures reveal electric field induced magnetization reversal in the single domain CFO nanodots through transfer of piezostrains from the piezoelectric PMN-PT substrate to the CFO. Further, electric field modulated spin structure of CFO nanomagnets is analyzed by using x-ray magnetic circular dichroism (XMCD). The XMCD analysis reveals cations (Fe3+/Co2+) redistribution on the octahedral and tetrahedral site in the electric field poled CFO nanodots, establishing the strain induced magneto-electric coupling effects. The CFO/SRO/PMN-PT nanodots structure demonstrate multilevel switching of ME coupling coefficient (α) by applying selective positive and negative electric fields in a non-volatile manner. The retention of two stable states ofαis illustrated for ∼106seconds, which can be employed to store the digital data in non-volatile memory devices. Thus the voltage controlled magnetization in the nanodot structures leads a path towards the invention of energy efficient high-density memory devices.

Family vitiligo impact scale: A scale to measure the quality-of-life of family members of patients with vitiligo.

BACKGROUND: Vitiligo places a significant psycho-social burden on caregivers and family members. AIMS: The aim of the study was to develop and preliminarily validate a scale to measure the psychosocial impact of vitiligo on adult family members. METHODS: Themes that emerged from qualitative interviews and a focus group discussion with family members were used to generate items for a preliminary scale, followed by pre-testing and scale development. The new scale was then tested with two comparator scales and a global question. RESULTS: A preliminary scale with 32 items was pilot tested on 30 participants. Following this, the scale was condensed to 16 items in 12 domains that were administered to 159 participants. Scale scores ranged from 0 to 48 with a mean of 19.75 ± 12.41. The scale had excellent internal consistency with Cronbach's alpha coefficient of 0.92 (0.70-0.95) and also showed good test-retest reliability at two weeks (r = 0.946). The scale showed criterion, convergent and known group validity. LIMITATIONS: It was conducted in a large teaching hospital which may have resulted in selection of patients with persistent or progressive disease and more worried family members. Vitiligo is highly stigmatized in our country and the performance of the scale may need to be evaluated in other communities and cultures as well where stigma is less oppressive. CONCLUSION: Family Vitiligo Impact Scale appears to be an easy-to-complete, reliable and valid instrument to measure the psychosocial impact of vitiligo in family members of patients. It may be useful as an outcome measure in both clinical and research settings.

Spin reorientation transition and coupled spin-lattice dynamics of Sm0.6Dy0.4FeO3.

In this work, we have presented a solid-solution of Sm0.6Dy0.4FeO3 in the form of nano-particles having spin reorientation transition (SRT) at a temperature interval of 220-260 K. The lattice dynamics of Sm0.6Dy0.4FeO3 have investigated by temperature-dependent x-ray diffraction and Raman spectroscopy. A negative thermal expansion at low temperatures has observed, which might be due to the interaction between Sm3+ and Fe3+ sublattice. Anomalous behavior in lattice parameters, octahedral tilt angle, and bond lengths have observed in the vicinity of SRT, which confirms the existence of magneto-elastic coupling in the system. The strong anomaly has observed in linewidth and phonon frequencies of Raman modes around SRT, which may be related to the spin-phonon coupling in Sm0.6Dy0.4FeO3. The contribution of SRT in lattice change and the presence of spin-phonon coupling can help to understand the correlation between the magnetic and structural properties of orthoferrite.

Magnetic properties and oxygen migration induced resistive switching effect in Y substituted multiferroic bismuth ferrite.

Multiferroic Y-doped BiFeO3 (BY10FO) thin films were deposited on FTO coated glass substrate using sol-gel spin coating technique. Y-doping causes structural distortion without changing the structure of the parent BiFeO3 (rhombohedral: R3c). The M-H hysteresis curve reveals that the BY10FO film exhibits saturation magnetization at a low-coercive field by suppressing the spiral spin modulated structure. The bipolar resistive switching behavior has been investigated on a Ag/BY10FO/FTO hetero-structure through conventional I-V curve measurements and the device can produce an ON/OFF ratio of around 12 over 30 complete testing cycles. The space charge limited current and Schottky barrier emission conduction mechanism play a crucial role in switching the states between HRS and LRS. The impedance spectroscopy analysis at HRS and LRS confirms the significant degradation of resistance from MΩ to kΩ. The switching mechanism in the hetero-structure is due to migration and recombination of oxygen vacancies present in the film. The non-degradation of the Ag/BY10FO/FTO device after several testing cycles confirms that the switching of resistance between ON and OFF states is reproducible, reversible and controllable to be used for possible future non-volatile resistive random access memory application.

Effect of Mg doping in Sr2 SiO4 :Eu2+ nanophosphors for blue and white emission at near-UV excitation.

Nanophosphors of (Sr0.98-x Mgx Eu0.02 )2 SiO4 (x = 0, 0.18, 0.38, 0.58 and 0.78) were prepared through low temperature solution combustion method and their luminescence properties were studied. The emission peak for Eu2+  -doped Sr2 SiO4 nanophosphor is observed at ~490 nm and ~553 nm corresponding to two Sr2+ sites Sr(I) and Sr(II) respectively for 395 nm excitation. However the addition of Mg2+ dopant in Sr2 SiO4 leads to suppression of ~553 nm emission peak due to absence of energy levels of Sr (II) sites which results in a single broad emission at ~460 nm. It was shown that the emission peak blue shifted with increase in Mg concentration which may be attributed to change in crystal field environment around Sr(I) sites. Therefore, the (Mg0.78 Sr0.20 Eu0.02 )2 SiO4 nanophosphor can be used for blue emission and the Sr2 SiO4 :Eu0.042+ for green-yellow emission at 395 nm excitations. The Commission International de L'Eclairage (CIE) chromaticity coordinates for mixed powders of (Mg0.78 Sr0.20 Eu0.02 )2 SiO4 and Sr2 SiO4 :Eu0.042+ (in a 1:1 ratio) fall in the white region demonstrating the possible use of the mixture in white light generation using near-UV excitation source.

Acute Sickle Hepatic Crisis after Liver Transplantation in a Patient with Hb SC Disease.

Acute sickle hepatic crisis (ASHC) has been observed in approximately 10% of patients with sickle cell disease. It occurs predominantly in patients with homozygous (Hb SS) sickle cell anemia and to a lesser degree in patients with Hb SC disease, sickle cell trait, and Hb S beta thalassemia. Patients commonly present with jaundice, right upper quadrant pain, nausea, low-grade fever, tender hepatomegaly, and mild to moderate elevations in serum AST, ALT, and bilirubin. We describe the case of a patient with a history of hemoglobin SC disease and cirrhosis caused by hepatitis C presenting approximately 1 year after liver transplantation with an ASHC. The diagnosis was confirmed by liver biopsy. Our patient was treated with RBC exchange transfusions, IV hydration, and analgesia and made a complete recovery. Only a limited number of patients with sickle cell disease have received liver transplants, and, to our knowledge, this is the first case of ASHC after transplantation in a patient with Hb SC disease.

A randomized controlled trial of lamivudine to treat acute hepatitis B.

UNLABELLED: The role of antivirals in patients with acute viral hepatitis B (AVH-B) has not been evaluated in controlled trials. The aim of this study was to evaluate the efficacy of lamivudine in patients with AVH-B. AVH-B patients with serum bilirubin of more than 5 mg/dL were randomized to receive either 100 mg of lamivudine daily for 3 months (group 1, n = 31) or placebo (group 2, n = 40). Patients were considered to have severe AVH-B if they fulfilled 2 of 3 criteria: (1) hepatic encephalopathy; (2) serum bilirubin > or = 10.0 mg/dL; and (3) international normalized ratio (INR) > or = 1.6. At week 4, HBV DNA levels were significantly lower (P = 0.037) in group 1 (median: 3.6721 log copies/mL) than group 2 (median: 4.2721 log copies/mL). Thereafter, HBV DNA levels were comparable in the 2 groups. The improvement in serum bilirubin, ALT, and INR values was similar in the 2 groups. Twenty-two patients (71%) in group 1 and 25 patients (62.5%) in group 2 had severe AVH-B. Results were similar when patients with severe AVH-B were analyzed separately. After 12 and 18 months, 93.5% and 92.5%, respectively, of patients in the lamivudine group and 96.7% and 97.5%, respectively, of patients in the placebo group lost HBsAg. There were no deaths in either group. After 1 year, 21 patients (67.7%) in group 1 and 34 patients (85%) in group 2 developed protective anti-HBs titers (P = 0.096). All HBeAg-positive patients in both groups lost e antigen and anti-HBe developed in 71% and 87.5% of patients in groups 1 and 2, respectively (P = 0.132). CONCLUSION: Though lamivudine causes a greater decrease in levels of HBV DNA, it does not cause significantly greater biochemical and clinical improvement as compared to placebo in patients with acute hepatitis B.

Profile of chronic hepatitis B virus in children in India: experience with 116 children.

BACKGROUND: Hepatitis B virus (HBV) infection in children is mostly asymptomatic and therefore the disease burden is likely to be under appreciated. There is limited information on the profile of chronic HBV infection in children from the Indian subcontinent. METHOD: In 116 (male:female 89:27) children, aged <15 years, with persistent HBsAg positivity for more than 6 months, a clinical, biochemical, virological and histological assessment was carried out. RESULTS: At presentation, 21.6% of children were symptomatic, with icterus in 12%. Features of decompensation such as ascites (7%) and gastrointestinal (GI) bleed (5%) were noted uncommonly. Five (4.3%) children had hepatocellular carcinoma (HCC) at presentation. Elevated alanine aminotransferase (ALT) was observed in 76% of subjects (median 61; range 14-815). A significantly higher proportion of children with hepatitis B early antigen (HbeAg) positive status had higher histological activity index (HAI) (84% vs 16%, P < 0.001) and fibrosis score (80% vs 20%, P = 0.007). A strong positive correlation was noted between aspartate aminotransferase (AST), ALT, HBV-DNA and histological severity of the disease (HAI > or =4, fibrosis > or =2). Median HBV-DNA levels were significantly higher in the HBeAg positive compared to the HBeAg negative group (25.6 vs 0.7 pg/mL, P = 0.004). Seventy-four percent of the mothers had evidence of past or present HBV infection. CONCLUSIONS: Majority of the children with chronic HBV infection are asymptomatic at presentation. HBeAg positive status reflects histologically more severe disease, and a higher level of HBV-DNA. Almost two-thirds of the children may have acquired their HBV infection perinataly.

Diaphragm disease of duodenum following long-term NSAIDs use: endoscopic management.

We report our experience with endoscopic management of 3 men (aged 62, 63 and 65 years) with duodenal diaphragm disease following NSAID use for 5-15 years. In the first patient a 24 F through-the-scope balloon dilatation was attempted but failed; he subsequently underwent gastro-jejunostomy. The other two patients subsequently underwent radial incisions of the web with mixed cutting and coagulation current using a standard 5 F sphincterotome.

Pharmacokinetics of omeprazole in patients with liver cirrhosis and extrahepatic portal venous obstruction.

Omeprazole is frequently used in patients with cirrhosis of the liver to treat peptic ulcer disease. It is also used for the healing of mucosal lesions after endoscopic sclerotherapy of esophageal varices in cirrhosis and extraheptic portal vein obstruction (EHPVO). This study was carried out with the aim of determining the pharmacokinetics of omeprazole in different degrees of liver cirrhosis and in patients with EHPVO, compared with healthy volunteers. Ten healthy volunteers, 30 patients with cirrhosis of the liver, divided into 3 groups of 10 depending on severity (according to Child-Pugh classification A, B and C) and ten patients with EHPVO participated in the study. The subjects received an omeprazole 20 mg capsule after an overnight fast. Blood samples were collected at 0, 0.5, 1, 1.5, 2, 2.5, 3, 6, 9 and 24 h after drug administration. Omeprazole level in plasma was estimated by reverse-phase high performance liquid chromatography (HPLC). The elimination half-life was significantly (p < 0.05) increased to 2.38 +/- 0.16, 3.26 +/- 0,12, 3.58 +/- 0.31 and 2.59 +/- 0.22 h in patients with different grades of cirrhosis (A, B and C) and also in patients with EHPVO, respectively, compared with 1.054 + 0.10 h in healthy volunteers. A similar significant increase (p < 0.05) was observed in the AUC(0alpha), while C(max) was significantly increased to 400.40 +/- 27.89 and 602 +/- 55.13 ng/ml in only grade C cirrhosis patients and EHPVO patients, compared with 303.5 +/- 36.42 ng/ml in healthy volunteers. No significant difference was observed in T(max). It was concluded that the metabolism of omeprazole was significantly impaired in both liver cirrhosis and EHPVO in comparison with healthy volunteers.

Pharmacokinetics of ciprofloxacin in patients with liver cirrhosis.

BACKGROUND: Bacterial infections are common in patients with cirrhosis of liver and are frequently treated with ciprofloxacin. Literature on pharmacokinetics of ciprofloxacin in patients with cirrhosis of the liver is scanty. The present study compared the pharmacokinetics of ciprofloxacin in cirrhotic patients with that in healthy volunteers. METHODS: In 20 patients with cirrhosis of liver (all Child-Pugh class B) and 10 healthy volunteers, plasma levels of ciprofloxacin were measured using high-performance liquid chromatography at several time points after a 500-mg oral dose. Various pharmacokinetic parameters were calculated. RESULTS: No significant differences were observed in maximum plasma levels reached (mean [SD] 2.6 [0.6] vs 2.6 [1.3] microg/ml), time taken for maximum plasma levels to be reached (1.3 [0.6] vs 1.5 [0.9] h), t1/2a (0.7 [0.3] vs 0.4 [0.9] h), elimination half-life (3.6 [1.2] vs 3.2 [1.8] h), and area under the curve (19.3 [3.8] vs 21.9 [4.5] microg/mL x h) in healthy volunteers and cirrhotic patients, respectively. CONCLUSIONS: Pharmacokinetics of ciprofloxacin is unaltered in patients with liver cirrhosis. Ciprofloxacin can be safely administered in the usual doses in such patients.

Hyposplenism in alcoholic cirrhosis, facts or artifacts? A comparative analysis with non-alcoholic cirrhosis and extrahepatic portal venous obstruction.

BACKGROUND AND AIMS: Hyposplenism has been described in patients with alcoholic cirrhosis (AC). However, no data are available regarding hyposplenism in patients with non-alcoholic cirrhosis (NAC) and other forms of portal hypertension such as extrahepatic portal venous obstruction (EHPVO). The aim is to study the splenic functions in patients with AC, NAC, and EHPVO. METHODS: Splenic functions were assessed consecutively in 22 patients with AC, 21 with NAC, and 23 with EHPVO. The tests included pitted red blood cells (RBC; %) and Howell-Jolly bodies in the peripheral smear. Pitted RBCs > 2% with or without the presence of Howell-Jolly bodies were taken as indicators of hyposplenism. The splenic function in each group was compared with age-matched controls. RESULTS: Hyposplenism was found in 10 (45.45%) patients with AC, six (28.57%) with NAC and one (4.34%) with EHPVO. The mean pitted RBCs were significantly increased in patients with AC (mean 4.93 +/- 1.36% vs control 1.22 +/- 0.17%, P < 0.05), but not so with NAC (2.01 +/- 0.69%) and EHPVO (mean 0.99 +/- 0.1% vs control 0.66 +/- 0.1%, P > 0.05). Howell-Jolly bodies were seen in only four patients. The mean pitted RBCs were significantly higher among patients who were actively consuming alcohol (9.14 +/- 3.35%) compared to those who abstained at least for more than 24 weeks (2.0 +/- 1.3%, P < 0.05). CONCLUSION: Hyposplenism is more common in AC patients, particularly those who are actively consuming alcohol compared with those who abstain. Patients with NAC have a lower incidence of hyposplenism, while in EHPVO patients, it is uncommon.