Creatinine as a normalization factor to estimate the representativeness of urine sample - Intra-subject and inter-subject variability studies.

In-vitro bioassay monitoring generally involves analysis of overnight urine samples (~12 h) collected from radiation workers to estimate the excretion rate of radionuclides from the body. The unknown duration of sample collection (10-16 h) adds to the overall uncertainty in computation of internal dose. In order to minimize this, IAEA recommends measurement of specific gravity or creatinine excretion rate in urine. Creatinine is excreted at a steady rate with normally functioning kidneys therefore, can be used as a normalization factor to infer the duration of collection and/or dilution of the sample, if any. The present study reports the chemical procedure standardized and its application for the estimation of creatinine as well as creatinine co-efficient in normal healthy individuals. Observations indicate higher inter-subject variability and lower constancy in daily excretion of creatinine for the same subject. Thus creatinine excretion rate may not be a useful indicator for extrapolating to 24 h sample collection.

COMPARING LUNGS, LIVER AND KNEE MEASUREMENT GEOMETRIES AT VARIOUS TIMES POST INHALATION OF 239Pu AND 241Am.

In-vivo measurement of Pu/241Am in workers is carried out by placing suitable detector above lungs, liver and skeleton, as major fraction of Pu/Am is transferred to liver and skeleton, after its retention in entry organ. In this work, committed effective dose (CED) corresponding to minimum detectable activity for Type M and Type S 239Pu/241Am deposited in these organs are presented and a monitoring protocol of organ measurement giving lowest CED at different time intervals post inhalation is described. We have observed, for Type M compounds, lung measurement is most sensitive method during initial days after exposure. Liver measurement yields lowest CED between 100 and 5000 d and beyond that bone measurement gives lowest CED. For Type S compounds lung measurement remains most sensitive method even up to 10 000 d post inhalation. This study will be useful for the assessment of CED due to internally deposited 239Pu/241Am in the workers.

Evaluation of uncertainties in lung measurement of actinides due to non-uniform distribution of activity in lungs.

Various parameters can introduce uncertainties in the lung activity measurements of actinides. In this study, uncertainties due to non-uniform distribution of activity in the lungs are evaluated. To study the effect of non-uniform distribution, lungs of ICRP male thorax voxel and resized phantoms are divided into upper and lower parts of both right and left lungs as well as into anterior and posterior lung regions. Simulation of uniform and non-uniform distribution of activity in lungs is carried out using thorax voxel phantoms in FLUKA for Phoswich and an array of three HPGe detectors for 18-238keV photons. Source sampling for non-uniform distribution of activity is carried out by selecting the source points by varying the weightage to 0.4, 0.5, 0.6 and 1 in different parts of lungs. Uncertainties in lung activity estimation at different energies are quantified in the form of scattering factors (SFs) which are geometric standard deviations. The SFs due to non-uniform distribution of activity of the order of 0.4-0.6 in different parts of the lungs are found to be ~ 1.25 for Phoswich and HPGe array detectors above 18keV.

A rapid method for estimation of Pu-isotopes in urine samples using high volume centrifuge.

The conventional radio-analytical technique used for estimation of Pu-isotopes in urine samples involves anion exchange/TEVA column separation followed by alpha spectrometry. This sequence of analysis consumes nearly 3-4 days for completion. Many a times excreta analysis results are required urgently, particularly under repeat and incidental/emergency situations. Therefore, there is need to reduce the analysis time for the estimation of Pu-isotopes in bioassay samples. This paper gives the details of standardization of a rapid method for estimation of Pu-isotopes in urine samples using multi-purpose centrifuge, TEVA resin followed by alpha spectrometry. The rapid method involves oxidation of urine samples, co-precipitation of plutonium along with calcium phosphate followed by sample preparation using high volume centrifuge and separation of Pu using TEVA resin. Pu-fraction was electrodeposited and activity estimated using 236Pu tracer recovery by alpha spectrometry. Ten routine urine samples of radiation workers were analyzed and consistent radiochemical tracer recovery was obtained in the range 47-88% with a mean and standard deviation of 64.4% and 11.3% respectively. With this newly standardized technique, the whole analytical procedure is completed within 9h (one working day hour).

An anatomical subunit-based outcome assessment scale for bilateral cleft lip and palate.

As there is currently no internationally accepted outcome measurement tool available for complete bilateral cleft lip and palate (CBCLP), the goal of this prospective study was to develop a numerical evaluation scale that allows reliable scoring of this cleft deformity. Our cohort comprised 121 Indian subjects with CBCLP who underwent surgical repair (mean age at time of surgery 6.53 months) using a modified Millard technique. A panel of three professionals evaluated each subject's outcome of bilateral cleft lip repair 6 months postoperatively on two-dimensional (2D) full-face photographs in the frontal view and worm's eye view. A simple two-point rating system was applied to separately analyse a total of 12 components of lip, nose, and scar. The results and mean scores for the analysed anatomical areas were 2.2±1.01 (max=3) for nose, 5.4±1.54 (max=8) for lip, and 1.9±1.3 (max=3) for scar, with a total score 7.7±2.21 (max=12) indicating a good surgical outcome. The inter-examiner ICC for nose, lip, scar, and total score was calculated at 0.836, 0.889, 0.723, and 0.927 respectively and indicated a strong level of repeatability and reliability that was highly significant (P<0.001). In conclusion, we were able to develop and test a scoring system for measuring outcomes in CBCLP that warrants simplicity of use, reliability and reproducibility.

METHODOLOGY FOR THE ASSESSMENT OF INGESTED ACTINIDES FROM MONTE CARLO SIMULATION OF VOXEL PHANTOM.

In case of internal contamination of actinides by ingestion pathway, activity will be transferred to various regions of the alimentary tract over a period of time. In this article, counting efficiencies (CEs) of Phoswich and an array of HPGe detectors are estimated for source in alimentary tract of voxel phantom. The phantom as well as Phoswich, and an array of three HPGe detectors are incorporated in Monte Carlo code 'FLUKA'. Human alimentary tract model is solved using default parameters to identify different compartments where activity will accumulate after an ingestion intake of 1 Bq as a function of time. Accordingly, CEs are evaluated on 0.5-5 d post ingestion intake for the source distributed in the contents of alimentary tract for photon energies in 18-238 keV range representing sources of actinides. The assessment of ingested activity of actinides from abdomen measurements is discussed. Higher CEs are observed with Phoswich detector compared with HPGe array due to its large size and high effective Z. Also, the CEs observed on Days 1-5 using both the detectors are found to decrease by 16-75 % with respect to the CE on half day. Thus, there is need to use CEs according to the observed activity distribution post ingestion intake. The contribution in the abdomen measurements due to source in the lungs and vice versa is also studied for intake by both inhalation and ingestion pathways. The contribution of source in the liver is found to be ∼30-50 % in chest and 75 % in abdomen measurements.

Heralded Control of Mechanical Motion by Single Spins.

We propose a method to achieve a high degree of control of nanomechanical oscillators by coupling their mechanical motion to single spins. Manipulating the spin alone and measuring its quantum state heralds the cooling or squeezing of the oscillator even for weak spin-oscillator couplings. We analytically show that the asymptotic behavior of the oscillator is determined by a spin-induced thermal filter function whose overlap with the initial thermal distribution of the oscillator determines its cooling, heating, or squeezing. Counterintuitively, the rate of cooling dependence on the instantaneous thermal occupancy of the oscillator renders robust cooling or squeezing even for high initial temperatures and damping rates. We further estimate how the proposed scheme can be used to control the motion of a thin diamond cantilever by coupling it to its defect centers at low temperature.

Correlation of vermilion symmetry to alveolar cleft defect in unilateral cleft lip repair.

Asymmetry is a major problem in repaired unilateral cleft lip (UCL). One of the important manifestations of this is the asymmetry of the vermilion. The aim of this study was to correlate the severity of the asymmetry in the vermilion to the size of the alveolar defect. Twenty patients aged between 6 and 18 months with complete unilateral cleft lip, alveolus, and palate were included. An impression of each patient's alveolus at the time of cheiloplasty was taken using silicon rubber base material, and a study cast was prepared. The width of the cleft alveolus was measured on these casts using a transparent grid. Frontal photographs were taken at 6 months postoperative and vermilion symmetry was measured as the ratio between the cleft and non-cleft sides. The results obtained in this study showed a direct correlation between the size of the alveolar defect and the vermilion symmetry in repaired UCL. The wider the cleft alveolus and greater the antero-posterior discrepancy, the greater is the vermilion asymmetry. The asymmetry of the vermilion in UCL after repair is directly dependent on the size of the alveolar defect. The alveolar discrepancy causes 'in-rolling' of the vermilion on the cleft side and affects the vermilion symmetry.

Indirect quantum sensors: improving the sensitivity in characterizing very weakly coupled spins.

We propose a scheme to increase the sensitivity and thus the detection volume of nanoscale single molecule magnetic resonance imaging. The proposal aims to surpass the T1 limited detection of the sensor by taking advantage of a long-lived ancillary nuclear spin to which the sensor is coupled. We show how this nuclear spin takes over the role of the sensor spin, keeping the characteristic time-scales of detection on the same order but with a longer life-time allowing it to detect a larger volume of the sample, which is not possible by the sensor alone.

Applying a low energy HPGe detector gamma ray spectrometric technique for the evaluation of Pu/Am ratio in biological samples.

The estimation of Pu/(241)Am ratio in the biological samples is an important input for the assessment of internal dose received by the workers. The radiochemical separation of Pu isotopes and (241)Am in a sample followed by alpha spectrometry is a widely used technique for the determination of Pu/(241)Am ratio. However, this method is time consuming and many times quick estimation is required. In this work, Pu/(241)Am ratio in the biological sample was estimated with HPGe detector based measurements using gamma/X-rays emitted by these radionuclides. These results were compared with those obtained from alpha spectroscopy of sample after radiochemical analysis and found to be in good agreement.