Activity Concentration of 137Cs in soil samples from Punjab province (Pakistan) and estimation of gamma-ray dose rate for external exposure

Punjab is one of the most populated provinces of Pakistan having 34 districts. There is always a need to have baseline background level information about 137Cs and the corresponding gamma-ray doses to the population. In this respect, soil samples were collected to a depth of 30-50 cm from all 34 district headquarters of the Punjab province of Pakistan and 137Cs activity concentrations were measured. 137Cs activity concentration was found to be in the range from 1.1 +/- 1.0 to 5.3 +/- 2.5 Bq kg(-1). The average value of estimated external gamma-ray dose rate from all 34 districts of Punjab province was computed to be 0.18 +/- 0.07 nSv h(-1) from 137Cs in soil samples. The measured 137Cs activity concentration range was compared with the reported ranges in the literature from some of the other locations in the world. Results obtained in this study show that 137Cs concentration is of a lower level in the investigated area. The average value of estimated external effective dose rate is found far below the dose rate limit of 1.0 mSv y(-1) for members of the general public recommended by the International Commission on Radiological Protection (ICRP) as well as the external gamma radiation dose of 0.48 mSv y(-1) received per head from the natural sources of radiation assessed by UNSCEAR (2000). It is concluded that 137Cs soil contamination does not pose radiation hazards to the population in the investigated areas.

Metal-Based Antibacterial and Antifungal Agents: Synthesis, Characterization, and In Vitro Biological Evaluation of Co(II), Cu(II), Ni(II), and Zn(II) Complexes With Amino Acid-Derived Compounds

A series of antibacterial and antifungal amino acid-derived compounds and their cobalt(II), copper(II), nickel(II), and zinc(II) metal complexes have been synthesized and characterized by their elemental analyses, molar conductances, magnetic moments, and IR, and electronic spectral measurements. Ligands (L(1))-(L(5)) were derived by condensation of beta-diketones with glycine, phenylalanine, valine, and histidine and act as bidentate towards metal ions (cobalt, copper, nickel, and zinc) via the azomethine-N and deprotonated-O of the respective amino acid. The stoichiometric reaction between the metal(II) ion and synthesized ligands in molar ratio of M : L (1 : 1) resulted in the formation of the metal complexes of type [M(L)(H(2)O)(4)]Cl (where M = Co(II), Cu(II), and Zn(II)) and of M : L (1 : 2) of type [M(L)(2)(H(2)O)(2)] (where M = Co(II), Cu(II), Ni(II), and Zn(II)). The magnetic moment data suggested for the complexes to have an octahedral geometry around the central metal atom. The electronic spectral data also supported the same octahedral geometry of the complexes. Elemental analyses and NMR spectral data of the ligands and their metal(II) complexes agree with their proposed structures. The synthesized ligands, along with their metal(II) complexes, were screened for their in vitro antibacterial activity against four Gram-negative (Escherichia coli, Shigella flexeneri, Pseudomonas aeruginosa, and Salmonella typhi) and two Gram-positive (Bacillus subtilis and Staphylococcus aureus) bacterial strains and for in vitro antifungal activity against Trichophyton longifusus, Candida albicans, Aspergillus flavus, Microsporum canis, Fusarium solani, and Candida glaberata. The results of these studies show the metal(II) complexes to be more antibacterial/antifungal against one or more species as compared to the uncomplexed ligands. The brine shrimp bioassay was also carried out to study their in vitro cytotoxic properties. Five compounds, (3), (7), (10), (11), and (22), displayed potent cytotoxic activity as LD(50) = 8.974 x 10(-4), 7.022 x 10(-4), 8.839 x 10(-4), 7.133 x 10(-4), and 9.725 x 10(-4) M/mL, respectively, against Artemia salina.

Antibacterial activity of 1-methyl-7-methoxy-beta-carboline and its phenacyl and coumarine analogues

Antibacterial activity of 1-methyl-7-methoxy-beta-carboline (harmaline) and its phenacyl and coumarine analogues 1-(3-nitro-phenyl)-(2-(7-methoxy-1-methyl-1,3,4,9-tetrahydro-beta-carbolin-2-yl)-ethanone (II), 1-(3,4-dihydroxy-phenyl)-2-(7-methoxy-1-methyl-1,3,4,9-tetrahydro-beta-carbolin-2-yl)-ethanone (III) 7-(methoxy-beta-carboline),15-24,de-hydro(19,20-dimethoxy)coumarine (IV), 7-(methoxy-beta-carboline)15-24,dehydro(20-methoxy)coumarine (V) were studied by disc diffusion method. All compounds were tested against three gram positive and four gram-negative bacteria. Parent compound showed good activity. All compounds revealed better results against gram positive as compared to gram-negative bacteria. 1-(3,4-Dihydroxy-phenyl)-2-(7-methoxy-1-methyl-1,3,4,9-tetrahydro-beta-carbolin-2-yl)-ethanone (III) was found most potent compound showing broad spectrum activity when compared with all synthesized analogues. Coumarine analogues showed more or less same activity indicating that number and position of methoxy groups are not important regarding antimicrobial activity.

Early results of Rotating Platform total knee replacement

We report on our early experiences with the Press Fit Condylar Rotating Platform (PFC-RP) total knee replacement prosthesis at University Malaya Medical Centre. This new prosthesis was introduced to Malaysia in 2001. It combines the rotating platform technology of Low Contact Stress (LCS) and the modularity of Press Fit Condylar (PFC) system. We performed 18 knee replacements using cruciate retaining prosthesis without patellar resurfacing in 10 patients and followed them up over a period of 16-month. A new operative strategy was developed to match the flexion and extension gaps. The pre- and post-operative assessments were made according to the American Knee Society Scores (AKSS). Post-operative pain relief, range of motion, knee score and functional score showed promising early results. The average knee rating improved from 28 to 91 (range 75-94). Average functional assessment improved from 26 to 82 (range 75-90). The radiographic assessments show correction of an average pre-operative varus of 140 to post-operative valgus of 50 (range 4-70). Early infection occurred in two knees. Both responded to aggressive debridement and antibiotics. Stiffness was encountered in one patient. There were no spinouts of the insert. We are satisfied that the implants are performing well at the one-year mark and will continue monitor this cohort.

Application of threshold-based acceleration change index (TACI) in heart rate variability analysis

Heart rate variability (HRV) analysis is a non-invasive and reliable means to assess an autonomic nervous system (ANS) function. Heart rate is a non-stationary signal that may contain indicators of current diseases and sometimes warnings about impending diseases. In this paper, we have proposed the threshold-based acceleration change index (TACI) for HRV analysis, which is calculated from the sign of differences of RR time series characterizing the dynamics of threshold crossings. It was found that TACI is robust in classifying various groups under different physiological and pathological conditions. We have studied the behavior of TACI for simulated time series (uncorrelated random data, sinusoidal time series and logistics map time series) and its robustness in the presence of artifacts for RR time series. The performance of TACI is evaluated for classifying normal sinus rhythm (NSR), congestive heart failure (CHF) and atrial fibrillation (AF). An unpaired Student's t-test was used to check significant differences between these groups and the degree of separation between these groups was quantified by using the area of a receiver operator curve.

The Fundamental Neutron Physics Facilities at NIST

The program in fundamental neutron physics at the National Institute of Standards and Technology (NIST) began nearly two decades ago. The Neutron Interactions and Dosimetry Group currently maintains four neutron beam lines dedicated to studies of fundamental neutron interactions. The neutrons are provided by the NIST Center for Neutron Research, a national user facility for studies that include condensed matter physics, materials science, nuclear chemistry, and biological science. The beam lines for fundamental physics experiments include a high-intensity polychromatic beam, a 0.496 nm monochromatic beam, a 0.89 nm monochromatic beam, and a neutron interferometer and optics facility. This paper discusses some of the parameters of the beam lines along with brief presentations of some of the experiments performed at the facilities.

Measurements of activity concentrations of naturally occurring radionuclides in soil samples from Punjab province of Pakistan and assessment of radiological hazards

The natural level of radioactivity in soil is one of the major causes of external gamma rays exposure. It was considered imperative to measure gamma-ray activity concentrations due to naturally occurring, potentially hazardous radionuclides from 232Th, 226Ra and 40K in soil samples from Punjab, the most populated province of Pakistan. The activity concentrations were measured in soil samples collected from all 34 district headquarters of Punjab province using a P-type coaxial high purity germanium (HPGe)-based gamma-ray spectrometer having a relative efficiency of 60%. The mean activity concentrations for 232Th, 226Ra and 40K were found to be 41 +/- 8, 35 +/- 7 and 615 +/- 143 Bq kg(-1), respectively in soil samples from all 34 district headquarters of Punjab. The mean values of radium equivalent index (Ra(eq)) and total annual external gamma radiation dose were found to be 141 +/- 27 Bq kg(-1)and 0.38 mSv, respectively. Since these estimated radiological impact assessment factors are lower than the recommended values there seems to be no potential radiological health hazard associated with the soils from the district headquarters in the Punjab province of Pakistan. Geological studies show that most of the soils in Punjab have developed on the extensive fluviatile deposits of five rivers and a stable ratio of natural activity concentrations is observed in soil samples of the areas under study.

Kerion: an unusual presentation in the otolaryngology department

A 19-year-old farmer was referred by his general practitioner as an emergency to our otolaryngology department complaining of marked breathlessness of a few hours duration. He gave a three-day history of painful swelling and hair loss in the beard area of the right side of the neck. His upper airway was compromised unless extension of the neck was maintained. Larynx and pharynx were normal. The acute symptoms settled with intravenous antibiotics and hydrocortisone. Culture of skin scrapings revealed a growth of Tricophyton verrucosum. The neck swelling subsided after a course of oral griseofulvin followed by terbinafine. Difficulty in breathing due to fungal infection of the neck has not been previously reported in the English literature.

Measurement of presynaptic zinc changes in hippocampal mossy fibers

The hippocampal mossy fiber terminals of CA3 area contain high levels of vesicular zinc that is released in a calcium-dependent way, following high-frequency stimulation. However the properties of zinc release during normal synaptic transmission, paired-pulse facilitation and mossy fiber long-term potentiation are still unknown. Using the fluorescent zinc probe N-(6-methoxy-8-quinolyl)-para-toluenesulfonamide, we measured fast mossy fiber zinc changes indicating that zinc is released following single and low levels of electrical stimulation. The observed presynaptic zinc signals are maintained during the expression of mossy fiber long-term potentiation, assumed to be mediated by an increase in transmitter release, and are enhanced during paired-pulse facilitation. This zinc enhancement is, like paired-pulse facilitation, reduced during established long-term potentiation. The correlation between the paired-pulse evoked zinc and field potential responses supports the idea that zinc is co-released with glutamate.

Thermal and cold neutron phase-contrast radiography

In this paper, we will discuss a phase-contrast imaging method that avoids the complications of interferometry to provide phase contrast in weakly absorbing samples. A transversely coherent neutron beam is used with the traditional radiography scheme. Images taken with this scheme show dramatic intensity variations due to sharp changes in the neutron wave refractive index. With some numerical processing these images may be used to reconstruct a quantitative phase radiograph of specimens imaged with this technique.

Revision of total hip arthroplasty using an anterior cortical window, extensive strut allografts, and an impaction graft: follow-up study

PURPOSE

To report the outcome of revised total hip arthroplasty procedures involving an anterior cortical window, extensive strut allografts, and an Exeter impaction graft.

METHOD

Eight patients (9 hips) with a mean age of 58 years underwent revision of total hip arthroplasty using the Exeter hip impaction graft system and strut allografts between 1995 and 1998. An extensile anterior approach was used, and an anterior cortical window was created in the femur, to remove the old implant. External strut allografts were attached by wires to provide cortical support. The mean follow-up duration was 74 months. Indications for surgery were aseptic loosening of previous implants in 8 hips and infection of one hip that had previously undergone total arthroplasty.

RESULTS

19 Dall Miles cables, 4 ordinary cerclage wires, and 8 cerclage wires tightened with the clincher knot technique were used to secure the allograft to the host bone. The strut grafts were found to be incorporated in all cases. No wires became loose. One patient developed 20 degrees of angulation at the allograft-host bone junction. Using the method of Fowler and Gie, we found that one femoral implant had subsided 2 mm within the cement mantle. Two other implants had 1 mm of subsidence at the cement bone interface, and one patient had a major subsidence of 15 mm that required revision.

CONCLUSION

Using an anterior cortical window in the femur to remove the old implant does not predispose to failure of the allograft to incorporate into the host bone.

Small stem Exeter total hip replacement: clinical and radiological follow-up over a minimum of 2.5 years

PURPOSE

To evaluate the clinical and radiological outcome in patients undergoing small stem Exeter total hip replacement.

METHODS

A total of 46 small stem Exeter total hip replacements were performed on 44 consecutive patients (18 men and 26 women) attending the University of Malaya Medical Centre. The mean age at the time of operation was 58 years (range, 24-81 years). Of the 46 procedures performed, 35 were primary total hip replacements and 11 were revision operations, with aseptic loosening of the original implant being the main indication for revision. The main indications for surgery in primary cases were avascular necrosis and rheumatoid arthritis. Clinical and radiographic outcomes were assessed at 6 weeks', 12 weeks', 6 months' follow-up, and annually thereafter. Postoperative cementing technique was also assessed.

RESULTS

The mean follow-up period was 4 years. The mean Oxford Hip Score improved from 46 points preoperatively to 17 points at the final follow-up examination. There were no revision operations, no implant breakages, and no excessive migration of the implants. The potential complications of implant failure due to smaller implant size and increased patient activity were not observed.

CONCLUSION

Due to the smaller size of Asian femora, the small stem Exeter implant is a very useful development. This study suggests that it will perform as well as its larger counterparts.

Quantitative phase radiography with polychromatic neutrons

We develop and experimentally demonstrate a formalism that allows accurate phase imaging using neutron sources producing highly polychromatic beams. The results of measurements from a rectangular block of silicon compare favorably with theoretical simulations based upon the known composition and geometry of the block. The increased flux and reduced exposure times will permit a simple extension of the technique to tomographic phase imaging.

Biochemical studies on marine fish oil part-I: effects of fish oil and lipid lowering drugs on HDL/LDL cholesterol levels

Omega-3 fatty acids present in fish oil are potent cholesterol lowering agents. This fact has drawn our attention to investigate their effects alone and in combination with competitive inhibitors, (hydrooxymethylglutaryl coenzume-A reductase). The naturally occurring omega-3 fatty acids i.e., polyunsaturated fatty acids (PUFAs), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in fish oil have been proved as anticholesterolemic agents. In order to observe their actions as lipid lowering agents, the present study has been carried out which deals with the synergistic effect of fish oil with that of Lovastatin and Gemfibrozil.

Precision neutron interferometric measurement of the nd coherent neutron scattering length and consequences for models of three-nucleon forces

We have performed the first high precision measurement of the coherent neutron scattering length of deuterium in a pure sample using neutron interferometry. We find b(nd)=(6.665+/-0.004) fm in agreement with the world average of previous measurements using different techniques, b(nd)=(6.6730+/-0.0045) fm. We compare the new world average for the nd coherent scattering length b(nd)=(6.669+/-0.003) fm to calculations of the doublet and quartet scattering lengths from several modern nucleon-nucleon potential models with three-nucleon force (3NF) additions and show that almost all theories are in serious disagreement with experiment. This comparison is a more stringent test of the models than past comparisons with the less precisely determined doublet scattering length of (2)a(nd)=(0.65+/-0.04) fm.

Technetium-99m direct radiolabeling of lanreotide: a somatostatin analog

Lanreotide, a synthetic octapeptide analog of a native hormone somatostatin, was labeled with a commonly available, inexpensive radionuclide 99mTc. Labeling was accomplished by reduction of the cysteine bridge, which provided sulfhydryl groups for chelation with 99mTc. Stannous chloride was used as reducing agent, while tartrate acted as transchelating agent. Lanreotide (100 microg), stannous chloride dihydrate (100 microg) and tartaric acid (64 microg) were dissolved in acetate/acetic acid buffer (pH 2.8). After overnight (approximately 18 h) incubation, approximately 444 MBq (12 mCi) 99mTc was added and kept in boiling water for 30 min. More than 97% labeling efficiency was confirmed by RP-HPLC, ITLC-SG and C18 cartridge analysis. Radiolabeling results in one major peak when analyzed by reverse-phase HPLC. The stability of the 99mTc-peptide bond was evaluated by cysteine challenge studies.