The role of the Ca vacancy in the determination of the europium position in the energy gap, its valence state and spectroscopic properties in KCa(PO3)3.

A new very promising red phosphor KCa1-xEux(PO3)3 (x = 1-5%) has been grown by the solid state method. Its luminescent quantum efficiency is close to 100% and the emission is stable over a wide temperature range i.e. 90% and 60% of the room temperature emission intensity remains at 200 °C and at 600 °C, respectively. The chromaticity coordinates were calculated as being x = 0.63, y = 0.37. The IR and Raman spectra were measured, and the maximum phonon energy of KCa1-xEux(PO3)3 is 1276 cm(-1). In the measured emission and excitation spectra of all samples only Eu(3+) ion emission was observed, emission of Eu(2+) is not present. Quantum mechanical calculations showed that in a perfect crystal the 5d levels of Eu(2+) are embedded in the conduction band. Consequently, neither absorption nor emission assigned to the Eu(2+) ions could be observed. The presence of a calcium vacancy is crucial for the explanation of the observed spectrum. The existence of a Ca(2+) vacancy compensates for the charge of Eu(3+) and results in the creation of the magnetic moment which moves the 4f levels to the valence band. Thus, transitions to the Eu(3+) excited levels located in the energy band gap are observed.

Structural and optical properties of nano-sized K3Nd(PO4)2:Yb3+ orthophosphate.

Nanocrystals of tripotassium neodymium bis-phosphate(V) doped with ytterbium ions, K3Nd(PO4)2: Yb3+, were synthesized by Pechini method. The obtained grains, having an average size of about 40 nm, were characterised by X-ray, electron microscopic, electron absorption, luminescence and IR studies. Moreover, fluorescence decay studies were carried out at room temperature. The energy transfer from the Nd3+ to Yb3+ was described and discussed. The results were compared to those of the K3Nd(PO4)2 bulk crystal.

DFT study of electron absorption and emission spectra of pyramidal LnPc(OAc) complexes of some lanthanide ions in the solid state.

The electron absorption and emission spectra were measured for the pyramidal LnPc(OAc) complexes in the solid state and co-doped in silica glass, where Ln=Er, Eu and Ho. The theoretical electron spectra were determined from the quantum chemical DFT calculation using four approximations CAM-B3LYP/LANL2DZ, CAM-B3LYP/CC-PVDZ, B3LYP/LANL2DZ and B3LYP/CC-PVDZ. It was shown that the best agreement between the calculated and experimental structural parameters and spectroscopic data was reached for the CAM-B3LYP/LANL2DZ model. The emission spectra were measured using the excitations both in the ligand and lanthanide absorption ranges. The possibility of energy transfer between the phthalocyanine ligand and excited states of lanthanide ions was discussed. It was shown that the back energy transfer from metal states to phthalocyanine state is responsible for the observed emission of the studied complexes both in the polycrystalline state and silica glass.

[Parathyroid hypofunction after total thyroidectomy for differentiated thyroid carcinoma--perspectives after long term observation and treatment]. / Niedoczynnosc przytarczyc po tyroidektomii calkowitej z powodu zróznicowanego raka tarczycy--perspektywa wieloletniej obserwacji i leczenia.

Hypoparathyroidism remains a serious complication of total thyroidectomy for differentiated thyroid carcinoma (DTC). In Brachytherapy Department 952 patients affected with DTC were followed up in the years 1996-2000. Radical total thyroidectomy was performed in 235 (24.6%) of cases, while the other 717 patients underwent complete rethyroidectomy. The incidence of hypoparathyroidism following radical operation and after complete rethyroidectomy was 15.74% and 23.43%, respectively. In patients operated in our institution, blood for calcium was analyzed daily for five days following the surgery. If calcium level was normal the next measurement was performed 4-5 weeks thereafter. Hypoparathyroidism was diagnosed later in postoperative period in many patients operated elsewhere. Asymptomatic hypocalcemia during the first week after the operation requires oral administration of calcium. If hypocalcemia requiring intravenous calcium supplementation does not resolve in a few days, vitamin 1(OH)D3 is introduced. Vitamin 1(OH)D3 and calcium carbonate play the main role in management of persistent hypocalcemia. In case of marked hypercalciuria thiazid diuretics are instituted. Low-phosphate diet is recommended. The aim of treatment of hypoparathyroidism is to restore normal serum calcium level with calciuria not exceeding 5 mg/kg/24 h, so to avoid hypocalcemic complications as well as vitamin D intoxication.

[Non-iodine-absorbing metastasis of differentiated thyroid cancer--therapeutic probe with 13-cis retinoic acid]. / Niejodochwytne przerzuty zróznicowanego raka tarczycy--próba terapii kwasem 13-cis-retinowym.

The absence of iodine uptake in metastases of differentiated thyroid carcinoma makes them unresponsive to treatment with radioiodine 131I. In many of such cases symptomatic treatment remains the only available therapy. The results of studies on partial redifferentiation of metastases of thyroid cancer achieved after cis-retinoid acid therapy have drawn attention to the possibility of restoration of iodine uptake in metastases after pretreatment with cis-retinoic acid (Roaccutane). 5 patients with iodine uptake-negative metastases of differentiated thyroid carcinoma were given Roaccutane in a dose 1.5 mg/kg/24 h daily for 6 weeks before the therapy with radioiodine. In none of the patients restoration of radioiodine uptake in metastases has occurred as shown in post-therapeutic total body scintigraphy.

[99mTc Tetrofosmin in diagnosis of distant metastases from differentiated thyroid cancer]. / 99mTc Tetrofosmin w diagnostyce przerzutów odleglych zróznicowanego raka tarczycy.

UNLABELLED: Technetium 99mTc(TF), non-specific tumor-searching tracer was evaluated for its ability to detect distant metastases of differentiated thyroid carcinoma (DTC) and its reliability in the follow-up of DTC. Whole body scintigraphy (wbs) was performed 20-30 min after intravenous injection of 740 MBq 99mTc tetrofosmin by means of a dual-head gamma-camera (followed by spot images if needed) in 61 patients (pts) with DTC; 52 pts with distant metastases in 131I whole body scintigraphy (34) or in other methods (x-ray, CT, ultrasound) (7) or with negative 131I whole body scan and elevated thyroglobulin (11). In the group of 52 pts with signs of neoplasm dissemination, 36 showed positive TF whole body scan (69%), 16 (31%) pts were TF-negative. 23 of 34 131I positive wbs were also TF positive (68%), 11 out of 34 were TF negative (32%). In a group of 7 pts with metastases in x-ray, CT or ultrasound 4/7 were positive (57%), 3/7 were TF negative (18%). In a control group of 11 persons (2 diseases-free, 9 with DTC in clinical remission) TF whole body scans were negative in all cases. CONCLUSIONS: Technetium 99mTc tetrofosmin is clinically useful for detecting distant metastases of differentiated thyroid carcinoma and deserves complementary clinical application in follow-up in such patients.

Structure, vibrational spectra and DFT characterization of the intra- and inter-molecular interactions in 2-hydroxy-5-methylpyridine-3-carboxylic acid--normal modes of the eight-membered HB ring.

Fourier transform IR and Raman spectra, XRD studies and DFT quantum chemical calculations have been used to characterize the structural and vibrational properties of 2-hydroxy-5-methylpyridine-3-carboxylic acid. In the unit-cell of this compound two molecules related by the inversion center interact via OH⋯N hydrogen bonds. The double hydrogen bridge system is spaced parallel to the (102) crystallographic plane forming eight-membered arrangement characteristic for pyridine derivatives. The six-membered ring is the second characteristic unit formed via the intramolecular OH⋯O hydrogen bond. The geometry optimization of the monomer and dimer have been performed applying the Gaussian03 program package. All calculations were performed in the B3LYP/6-31G(d,p) basis set using the XRD data as input parameters. The relation between the molecular and crystal structures has been discussed in terms of the hydrogen bonds formed in the unit cell. The vibrations of the dimer have been discussed in terms of the resonance inside the system built of five rings coupled via hydrogen bonds.