DEVELOPMENT OF NACL-BASED OPTICALLY STIMULATED LUMINESCENT PHOSPHORS FOR THE POSSIBLE APPLICATIONS IN DOSIMETRY.

New highly sensitive optically stimulated luminescent phosphors with NaCl moiety and dopants Ca,Cu,P/Mg,Cu,P are developed. These phosphors show very high optically stimulated luminescence (OSL) sensitivity. The dose response for NaCl:Ca,Cu,P is linear up to 1.2 Gy and for NaCl:Mg,Cu,P is slightly sub linear from 0.2 Gy. These phosphors show 30% fading during first 4 and later signal gets stabilised with no further signal loss. These sensitive phosphors will find applications in radiation dosimetry using OSL.

PHASE DEPENDENT OPTICALLY STIMULATED LUMINESCENCE IN CU-DOPED Sr4Si3O8Cl4.

Phase dependent optically stimulated luminescence (OSL) is studied in Cu-doped Sr4Si3O8Cl4. The Study shows that samples in which amount of contributing strontium metasilicate phase in Cu-doped Sr4Si3O8Cl4 is less, show intense OSL while those samples in which strontium metasilicate phase is more show weak OSL. The observed Cu luminescence is also found to be phase dependent. Sample in which Sr4Si3O8Cl4 phase is dominant, the observed Cu luminescence is around 350 nm whereas an additional longer wavelength band around 450 nm is observed when the strontium metasilicate phase is present in significant amount. The relatively phase pure, Cu-doped Sr4Si3O8Cl4 shows good OSL properties. The sensitivity of such material is 3.89 times more compared to commercial Al2O3:C (Landauer Inc.). High sensitivity, good linearity and reusability, along with low fading make this material as good OSL phosphor and may find applications in OSL based radiation dosimetry.

PHOTOLUMINESCENCE, THERMOLUMINESCENCE AND OPTICALLY STIMULATED LUMINESCENCE STUDIES IN ZINC-BASED FLUOROPERVOSKITES.

The optically stimulated luminescence, thermoluminescence and photoluminescence in various Cu and Ag doped zinc based fluoropervoskites are studied. In all the samples, photoluminescence of Cu+ and Ag+ is observed which could be attributed to 3d94 s1←→3d10 and 4d95 s1←→5d10 transitions, respectively. The observed emission is double humped and the main emission band shifts to the lower wavelength side with increasing ionic size of the alkali ion. All the studied fluoropervoskites show reasonable OSL sensitivity. Highest sensitivity is observed for Cu doped ZnNaF3 and is 25% compared to commercial Al2O3:C. Weak thermoluminescence is observed in all samples. In all Ag doped samples the TL peak is observed at 200°C whereas for Cu doped samples peak is observed at 150°C, and correlated with the OSL. The samples show good linear dose response in the 10 mGy-1.2 Gy range and show good reusability characteristics. This study will lead to the development of zinc-based fluoropervoskite phosphors for the radiation dosimetry using OSL.

Optically stimulated luminescence study in rare earth doped SrBPO5.

Optically stimulated luminescence (OSL) was studied in rare earth doped SrBPO5 for the possible applications in radiation dosimetry using optically stimulated luminescence. The study shows that the sensitivity of the Eu doped SrBPO5 shows good OSL and the sensitivity is comparable to that of Al2O3:C. It is observed that annealing has a profound effect on the OSL sensitivity. Slowly cooled Eu doped sample shows highest sensitivity and is 77% compared to that Al2O3:C whereas lowest sensitivity is observed in the quenched sample. Other properties like good linearity and low fading will make this phosphor suitable for the applications in radiation dosimetry using OSL.

Hydroxyurea-Lactose Interaction Study: In Silico and In Vitro Evaluation.

The Maillard reaction between hydroxyurea (a primary amine-containing drug) and lactose (used as an excipient) was explored. The adduct of these compounds was synthesized by heating hydroxyurea with lactose monohydrate at 60 °C in borate buffer (pH 9.2) for 12 h. Synthesis of the adduct was confirmed using UV-visible spectroscopy and Fourier transform infrared, differential scanning calorimetry, high-pressure liquid chromatography, and liquid chromatography-mass spectrometry studies. An in silico investigation of how the adduct formation affected the interactions of hydroxyurea with its biological target oxyhemoglobin, to which it binds to generate nitric oxide and regulates fetal hemoglobin synthesis, was carried out. The in silico evaluations were complemented by an in vitro assay of the anti-sickling activity. Co-incubation of hydroxyurea with deoxygenated blood samples reduced the percentage of sickled cells from 38% to 12 ± 1.6%, whereas the percentage of sickled cells in samples treated with the adduct was 17 ± 1.2%. This indicated loss of anti-sickling activity in the case of the adduct. This study confirmed that hydroxyurea can participate in a Maillard reaction if lactose is used as a diluent. Although an extended study at environmentally feasible temperatures was not carried out in the present investigation, the partial loss of the anti-sickling activity of hydroxyurea was investigated along with the in silico drug-target interactions. The results indicated that the use of lactose in hydroxyurea formulations needs urgent reconsideration and that lactose must be replaced by other diluents that do not form Maillard adducts.

Metal Quinolates as Phosphors for PC-LED Applications.

Metal quinolates, Liq Alq3 Znq2 Mgq2 exhibit efficient luminescence in blue green region and find applications as emission layer in OLEDs. In most of these quinolates the excitation spectra are broad in the range 350 to 410 nm, just short of emission spectra of efficient GaN based blue LEDs. In this paper we report metal quinolates synthesized by slightly modified method in which the excitation gets extended beyond 450 nm so that there is better overlap between emission spectra of blue LED and the excitation spectra. Therefore these phosphors may be used for PC-LED applications.

Effect of Al(3+) co-doping on the luminescence properties of Cu doped Na2SiF6.

Studies were carried out to assess the correlation between thermoluminescence (TL) and optically stimulated luminescence (OSL) of this phosphor. It was observed that the OSL and TL glow curve consists of a wide distribution of traps having different photo-ionization cross-sections, trap depths and frequency factors. In case of Al doped sample, some of the traps up to 200°C are assumed to act as a source traps for the observance of OSL due to thermal transfer of charge carriers into the deep traps beyond 480°C. This suggests that Al impurities play an important role in the thermal transfer OSL process. As most of the work on this phenomenon is done on natural materials (mainly quartz) in which aluminum is a natural impurity, this study will explain the role of Al in this phenomenon.

Optically stimulated luminescence in doped NaF.

OSL in doped NaF is studied. Study shows that NaF:Mg,Cu,P phosphor possess good OSL properties having sensitivity comparable to that of commercially available Al2O3:C (Landauer Inc.). For the luminescence averaged over 3s the obtained OSL is 37% of that commercial available Al2O3:C. Of the several phosphors investigated, phosphor with impurities concentration Mg(0.01mol%), Cu(0.2mol%), P(1mol%) shows good OSL sensitivity good linearity in the 10mGy to 1Gy dose range and negligible fading. This sample shows a intense single TL peak around 350°C which gets depleted by 14% after the OSL readout. This imply that maximum OSL is coming from deep traps giving stability to the signal. The ease of preparation along with other good OSL properties will make this phosphor suitable for radiation dosimetry applications using OSL.

A new highly sensitive low-Z LiF-based OSL phosphor for radiation dosimetry.

A new low-Z lithium fluoride-based optical stimulated luminescent (OSL) phosphor is developed. The phosphor shows good OSL properties, and its sensitivity is comparable with that of the commercial Al2O3:C (Landauer, Inc.) phosphor. For the luminescence averaged over initial 3 s, blue stimulated luminescence (BSL) and green stimulated luminescence (GSL) sensitivities were found to be 0.27 and 4 times, respectively, than that of Al2O3:C (Landauer, Inc.). The BSL decay is fast, and the whole signal decays within 3 s; the GSL decay is relatively slow, and the signal decays in 25 s. The fast decay, good sensitivity, good linearity and its near tissue equivalence (Zeff ∼8.14) will make this phosphor suitable for radiation dosimetry particularly in personnel as well as in medical dosimetry.

Optically stimulated luminescence studies in combustion synthesized Al2O3:C,Cu,P.

A new Al2O3:C,Cu,P phosphor is developed by the combustion synthesis technique which exhibits entirely different OSL properties as compared to that of the commercial alumina. No thermoluminescence (TL) is observed in this phosphor which also differentiates the present phosphor from the commercially available Al2O3:C (Landauer). The phosphor shows good optically stimulated luminescence (OSL) sensitivity for ionizing radiation with a fast OSL decay as compared to the commercial Al2O3:C. The phosphor heated in air followed by heating under the reactive atmosphere exhibits maximum sensitivity amongst several other phosphors. On the basis of area integration method; integrated over initial 3s, the sensitivity of this phosphor is about 67% of that of commercial Al2O3:C.

Na2SiF6:Cu,P: a new OSL phosphor for the radiation dosimetric applications.

A new Cu,P-doped, sodium fluorosilicate-based optically stimulated luminescence (OSL) phosphor is developed. This phosphor shows good OSL properties, and the sensitivity is comparable with that of the commercial Al(2)O(3):C (Landauer, Inc.) phosphor. For the luminescence averaged over initial 1 s, blue-stimulated luminescence and green-stimulated luminescence sensitivities were found to be 0.76 and 3.8 times, respectively, of Al(2)O(3):C (Landauer, Inc.) with 28 % of post-irradiation fading in 3 days and nil thereafter. The simple preparation procedure, fast decay, very good sensitivity and moderate fading will make this phosphor suitable for radiation dosimetry, using OSL.

Hypolipidemic and antioxidant activity of ethanolic extract of Symplocos racemosa Roxb. in hyperlipidemic rats: an evidence of participation of oxidative stress in hyperlipidemia.

Hypolipidemic and antioxidant activity profiles of ethanolic extracts of Symplocos racemosa (EESR) were studied by triton-WR1339 (acute) and high fat diet induced (chronic) hyperlipidemic rat models. In both the models, a significant increase in total cholesterol (TC), triglycerides (TG), very low density lipoproteins (VLDL), low density lipoproteins (LDL) and decrease in high density lipoproteins (HDL) in serum were observed. EESR (200 and 400 mg/kg) and simvastatin (10 mg/kg) administered orally reduced the elevated serum lipids (TC, TG, VLDL, LDL), restored the decreased HDL and improved the atherogenic index. In high fat diet induced hyperlipidemic model, EESR treatment prevented the increased formation of malondialdehyde (MDA) in liver, restored the depleted liver antioxidants, glutathione, superoxide dismutase, catalase significantly. The increased liver cholesterol, HMG-CoA reductase activity and body weight of hyperlipidemic rats were significantly reduced by EESR treatment. The EESR inhibited HMG-CoA reductase, a rate limiting enzyme in cholesterol biosynthesis, thereby causing hypolipidemic effects. EESR treatment also improved histoarchitecture of hepatocytes in hyperlipidemic rats. Experimental findings demonstrated anti-hyperlipidemic and antioxidant activity of EESR, which may be directly or indirectly related to its antioxidant activity. The hypolipidemic activity of EESR may be due to the presence of flavonoids phenolic compounds, phenolic glycosides and steroids.

Operational feasibility of establishing community reporting systems.

BACKGROUND: In developing countries the absence ofa credible disease surveillance system results in an inappropriate response to an outbreak. Since a functioning and responsive disease surveillance system cannot be provided immediately, some interim surveillance system for early detection of outbreaks is needed to institute a prompt response. This operational research study was conducted to assess the feasibility of establishing community reporting systems involving women self-help groups and members of Panchayati raj institutions through syndromic surveillance at the community level. METHODS: Reporting was initiated from 8 villages in 4 gram panchayats of Begunia block of Khurda district in Orissa during May and June 2005. Members of women self-help groups and Panchayati raj institutions were trained on structured reporting guidelines. In congruence with the state disease surveillance system, weekly reporting was started for comparison where feasible. RESULTS: Completeness of reporting was better achieved by women self-help groups (91.6%) than members of Panchayati raj institutions (66.6%). Data capture was more complete as compared with the existing disease surveillance system. Illnesses among women were better captured and greater ownership of the public health service was noted. CONCLUSION: Establishing community reporting systems using women self-help groups and members of Panchayat raj institutions for disease surveillance in India is a feasible option.

Granulocyte-macrophage colony-stimulating factor expression by human fibroblasts is both upregulated and subsequently downregulated by interleukin-1.

Interleukin-1 (IL-1) treatment of human WI-38 lung fibroblasts results in granulocyte-macrophage colony-stimulating factor (GM-CSF) expression as well as a delayed increase in prostaglandin E2 (PGE2) production that closely correlates with the decline of GM-CSF mRNA levels. Pretreatment with PGE2 reduces the IL-1 induced GM-CSF mRNA and protein expression to 10% to 15% of control values at concentrations of PGE2 that are endogenously produced after IL-1 stimulation. Inhibition of PGE2 synthesis by indomethacin prolongs the IL-1 induced GM-CSF mRNA expression and increases the cumulative GM-CSF protein secretion. Exposure of WI-38 fibroblasts to PGE2 results in an increase in intracellular cyclic adenosine monophosphate (cAMP) levels. The inhibition of GM-CSF expression by PGE2 can be mimicked by stable cAMP analogs as well as cAMP elevating agents such as cholera toxin, forskolin, and isobutylmethylxanthine. Thus the inhibition exerted by PGE2 is mediated via cAMP. Taken together, these results suggest that IL-1 stimulation of human fibroblasts provides not only the upregulatory signal for GM-CSF expression but also a delayed and indirect downregulatory signal that serves to limit GM-CSF expression in the continued presence of IL-1.

Idiopathic extensive spontaneous venous thrombosis (a case report).

Two patients with extensive spontaneous venous thrombosis are reported. Both had documented evidence of polyserositis, transient abnormalities of liver function tests along with normal coagulograms. Although one patient had a short, self-limiting illness, the other required treatment with coumarin derivatives. The relevant literature is discussed.