Alfvén solitons in a Fermionic quantum plasma

The propagation of Alfvén envelope solitons through a Fermionic quantum plasma is considered. Starting from the governing equations for Hall magnetohydrodynamics including quantum corrections, coupled Zakharov-type equations are derived for circularly polarized Alfvén waves. The equations are numerically solved for time-independent and time-dependent cases. The time-independent case shows that variations in density take the form of dressed density solitons in which an approximately Gaussian peak is surrounded by smaller sinusoidal variations in the density envelope. The mathematical basis for this behavior is explained. A limited time-dependent case is obtained which uses the numerical time-independent soliton solutions as the initial conditions. This confirms that the soliton solutions retain the same profile as they propagate. The relevance of this work to dense astrophysical plasmas like the interiors of white dwarf stars is discussed.

Classical relativistic model for spin dependence in a magnetized electron gas

The response of a cold electron gas is generalized to include the spin of the electron described by the relativistically correct quasiclassical Bargmann-Michel-Telegdi (BMT) equation. The magnetization of the electron gas is assumed to be along the background magnetic field B and the spin-dependent contribution to the response tensor is proportional to the magnitude of the magnetization. The dispersion equation is shown to be quadratic in the refractive index squared, and dispersion curves for the two wave modes are plotted for cases where the magnetic field associated with magnetization is comparable with B. Two intrinsically spin-dependent wave modes are identified: one bounded by two resonances and the other by two cutoffs. The counterpart of the z mode can escape without encountering a resonance or a cutoff.

Dispersion in a thermal plasma including arbitrary degeneracy and quantum recoil

The longitudinal response function for a thermal electron gas is calculated including two quantum effects exactly, degeneracy, and the quantum recoil. The Fermi-Dirac distribution is expanded in powers of a parameter that is small in the nondegenerate limit and the response function is evaluated in terms of the conventional plasma dispersion function to arbitrary order in this parameter. The infinite sum is performed in terms of polylogarithms in the long-wavelength and quasistatic limits, giving results that apply for arbitrary degeneracy. The results are applied to the dispersion relations for Langmuir waves and to screening, reproducing known results in the nondegenerate and completely degenerate limits, and generalizing them to arbitrary degeneracy.

Synthesis and biodistribution of 99mTc-Vancomycin in a model of bacterial infection

Vancomycin Hydrochloride is an antibiotic produced by the growth of certain strains of Streptomyces orientalis. As Vancomycin Hydrochloride is poorly absorbed after oral administration; it is given intravenously for therapy of systemic infections. Vancomycin was labeled with technetium-99m pertechnetate using SnCl2·2H2O as reducing agent. The labeling efficiency depends on ligand/reductant ratio, pH, and volume of reaction mixture. Radiochemical purity and stability of 99mTc-Vancomycin was determined by thin layer chromatography. Biodistribution studies of 99mTc-Vancomycin were performed in a model of bacterial infection in Sprague–Dawley rats. A significantly higher accumulation of 99mTc-Vancomycin was seen at sites of S. aureus infected animals. Whereas uptake of 99mTc-Vancomycin in turpentine inflamed rats were quite low.

Lead (Pb) column for concentration of 99mTc-pertechnetate

Because of the high content of inactive molybdenum in neutron irradiated MoO3, large columns containing alumina or gel are needed to produce chromatographic 99Mo→99mTc generator. This results in large elution volumes containing relatively high 99Mo breakthrough and low concentrations of 99mTcO4 -. The decrease in specific volume of 99mTc places a limitation on reconstitution of some kits for 99mTc radiopharmaceuticals applied in diagnostic nuclear medicine. Hence concentration technique is mandatory for effective utilization of (n,γ) produced 99Mo/99mTc generators at the start of its life whereas in case of fission 99Mo/99mTc generator the technique may be quite useful at the end of first week of its life. We report post elution concentration of 99mTc using in house prepared Pb column. The high bolus volumes (10–60 ml saline) can conveniently be concentrated in ∼1 ml of saline.

Extraction of medically interesting 188Re-perrhenate in methyl ethyl ketone for concentration purposes

The high bolus volumes (20–40mL) of the generator-produced Rhenium-188 require post elution concentration of the eluate for the preparation of a dissolved β− source and radiopharmaceuticals labeled with Re-188 for radiotherapy. Solvent extraction of 188Re in methyl ethyl ketone was studied. With the increase of organic phase volume, extraction of 188Re was enhanced while mixing time of aqueous and organic phases did not show any significant effect on the extractability of 188Re in the organic phase. Almost 80% of 188Re was extracted in methyl ethyl ketone at a volume ratio of 1:2 for aqueous and organic phases. By evaporation/distillation of methyl ethyl ketone, 188Re was concentrated and dissolved in the desired volume of physiological saline.

Preparation of188Re-lanreotide peptide and its quality control

A simple method is described for the preparation of188Re-Lanreotide, a radiolabeled synthetic peptide derived from an analogue of somatostatin, using Lanreotide (50 μg) and stannous tartrate to which is added carrier-free188Re. The radiolabeling has been carried out with ~555 MBq (15 mCi) with a >95% labeling efficiency and no need for subsequent purification. ITLC and HPLC techniques were employed for monitoring the stability and labeling yield. Radiolabeling results in one major peak when analyzed by reverse-phase (RP) HPLC.

Concentration of 99mTc-pertechnetate and 188Re-perrhenate

The radioactive concentrations of 99mTc/188Re from their generators are dependent upon the specific activity of 99Mo/188W, which dictates the bed size of the alumina/gel column and the volume of physiological saline needed as eluent. Because of the high content of inactive molybdenum/tungsten in neutron irradiated MoO3/WO3, large columns containing alumina/gel are needed to produce chromatographic 99Mo → 99mTc/188W → 188Re generators. This results in large elution volumes containing relatively high 99Mo/188W contents and low concentrations of 99mTc/188Re. The decrease in radioactive concentration, or specific volume, places a limitation on some of the clinical procedures. We report post elution concentration of 99mTc/188Re using in house prepared silver cation exchange and alumina column. The high bolus volumes (10 − 60 ml saline) can conveniently be concentrated in 1 ml of saline. This approach also works very effectively to yield high specific volume solutions of 99mTc-pertechnetate from a fission 99Mo loaded alumina generator towards the end of its normal working life.

Ictal and interictal phonophobia in migraine-a quantitative controlled study

The aim of the study was to evaluate quantitatively ictal and interictal phonophobia in episodic migraine (EM). We included subjects with EM and age- and gender-matched controls. Sound stimuli were pure tones at frequencies of 1000, 4000 and 8000 Hz. Sound aversion thresholds (SATs) were determined as the minimal sound intensity perceived as unpleasant or painful. Migraineurs were examined both between and during attacks. We compared interictal SATs in migraineurs with those in controls. We also compared ictal and interictal SATs in migraineurs. Sixty migraineurs and 52 controls were included. Interictal mean SAT of migraineurs, averaged for the three frequencies, was significantly lower than that of controls [90.4 (0.8) dB vs. 105.9 (1.1) dB, respectively, P < 0.0001]. In migraineurs, mean ictal SAT, averaged for the three frequencies, was significantly lower than interictal SAT [76.0 (0.9) dB vs. 91.0 (0.8) dB, respectively, P < 0.0001]. Patients with EM exhibit increased sound aversion between attacks that is further augmented during an acute attack.

Sodium sulfate as an eluant for concentrated solution of pertechnetate

Fission molybdenum-99 based technetium-99m chromatography generators are the most widely employed generator systems in the field of diagnostic nuclear medicine. In the first week these generators provide high specific volume activity Na99mTcO4, but in the second week the radioactive concentration of the eluate (99mTc) becomes 17% of that at the beginning of the first week. Low specific volume activity limits the clinical procedures (e.g. 99mTc-DTPA for lung ventilation scanning, 99mTc-sestamibi for myocardial perfusion studies, 99mTc-ECD for brain imaging and 99mTc-red cells for testicles) that can be performed at the beginning of the second week. To overcome such limitations sodium sulfate was used as an eluant, which provides>80% of 99mTc radioactivity in 2 ml solution, while 0.9% NaCl provides only 40-45% 99mTc in first 2 ml solution.

Granulocyte colony-stimulating factor dosing in pegylated interferon alpha-induced neutropenia and its impact on outcome of anti-HCV therapy

Many patients with chronic hepatitis C (HCV) infection undergoing treatment with pegylated interferon-alpha (PEG-IFN-alpha) and ribavirin develop neutropenia requiring dose reduction or granulocyte colony-stimulating factor (G-CSF) supplement. We analysed the database of patients who completed treatment for chronic HCV infection between 2003 and 2006. Patients with absolute neutrophil counts below 1000 cells/microL were initiated on G-CSF (G-CSF group) while a matching group of patients who received anti-HCV treatment without developing neutropenia were used as a control group (non-G-CSF group). Patients on the G-CSF arm were divided into two subgroups based on the timing of G-CSF administration relative to PEG-IFN-alpha administration. Of the 163 patients with HCV infection, 30 patients received G-CSF, most of who were maintained on 300 microg of G-CSF once a week. Administration of G-CSF 2 days before or after each dose of PEG-IFN-alpha did not make a significant difference in the neutrophil counts. In the G-CSF arm, 23 of 30 patients (77%) had undetectable end-of-treatment viral response which was comparable with 27 of 30 in the control group (90%; P = 0.17). There was no statistically significant difference in the sustained viral response between the two groups (61%vs 76%, P = 0.18). In most patients PEG-IFN-alpha induced neutropenia improved with a once-a-week dose of G-CSF with a comparable virological outcome. Timing of G-CSF administration did not make any significant impact on the patient's neutrophil counts but was better tolerated when given 2 days apart from PEG-IFN-alpha.