Perla Subbaiah

A note on multivariate capability indices

In manufacturing industry, there is growing interest in quantitative measures of process variation under multivariate setting. This paper introduces a multivariate capability index and focuses its applications in geometric dimensioning and tolerancing. This index incorporates both the process variation and the process deviation from target. Two existing multivariate indices are compared with the proposed index.

Diet-induced obesity promotes myelopoiesis in hematopoietic stem cells

Obesity is associated with an activated macrophage phenotype in multiple tissues that contributes to tissue inflammation and metabolic disease. To evaluate the mechanisms by which obesity potentiates myeloid activation, we evaluated the hypothesis that obesity activates myeloid cell production from bone marrow progenitors to potentiate inflammatory responses in metabolic tissues. High fat diet-induced obesity generated both quantitative increases in myeloid progenitors as well as a potentiation of inflammation in macrophages derived from these progenitors. In vivo, hematopoietic stem cells from obese mice demonstrated the sustained capacity to preferentially generate inflammatory CD11c+ adipose tissue macrophages after serial bone marrow transplantation. We identified that hematopoietic MyD88 was important for the accumulation of CD11c+ adipose tissue macrophage accumulation by regulating the generation of myeloid progenitors from HSCs. These findings demonstrate that obesity and metabolic signals potentiate leukocyte production and that dietary priming of hematopoietic progenitors contributes to adipose tissue inflammation.

Evaluation of image quality using 1 : 1 pitch and 1.5 : 1 pitch helical CT in children: a comparative study.

ObjectiveThe objective of this study was to compare the quality of 1∶1 and 1.5 ∶1 pitch helical contrast-enhanced thoracic and abdominal CT images in children who cannot cooperate for breath holding.Materials and methodsThis is a retrospective study of 33 contrast-enhanced CT examinations in 11 children of 0–4 years of age. All children had an initial CT study using 1∶1 pitch helical scanning followed over the next 6–36 months by one to four CT examinations with 1.5∶1 pitch. Radiation dose with the two techniques was measured with a pencil Ionization chamber.ResultsThe two techniques provided comparable overall image quality. There was 33 % less radiation dose with 1.5∶1 pitch helical scanning.ConclusionThe 1.5∶1 pitch helical CT provides comparable quality images and a smaller radiation dose than 1∶1 pitch in examining children aged 0–4 years.

Tissue ferritin concentration and prognosis in carcinoma of the breast

SummarySeven year follow-up data were available on 36 of 40 breast carcinoma patients in whom breast tissue ferritin concentrations at the time of surgery were known. 18 patients were alive and free of recurrence or second tumor (Group 1) and 11 died with breast cancer (Group 2). Patients with lower tissue ferritin concentrations defined as < 319 ng/mcp (nanograms of ferritin/milligram of cytosol protein) were at reduced risk: 86% of patients with low tissue ferritin concentration survived free of recurrence or second tumor vs. 40% of patients with high tissue ferritin concentration (P = 0.0056). Mean breast carcinoma tissue ferritin concentration was 295 ± 52 ng/mcp in Group 1 and 444 ± 55 ng/mcp in Group 2 (P = 0.036).Lymph node involvement was predictive of mortality from breast carcinoma (P = 0.0003), but did not correlate with mean tissue ferritin concentration (P = 0.082). 10/10 (100%) patients who had both low tissue ferritin concentration and absence of lymph node involvement were in Group 1.The correlation of breast tissue ferritin concentration with histopathologic dedifferentiation and with prognosis suggests tumor tissue ferritin as a marker of malignant potential.

Inference on the capability index: Cpm

In this paper properties of two estimators of Cpm are investigated in terms of changes in the process mean and variance. The bias and mean squared error of these estimators are derived. It can be shown that the estimate of Cpm proposed by Chan, Cheng and Spiring (1988) has smaller bias than the one proposed by Boyles (1991) and also has a smaller mean squared error under certain conditions. Various approximate confidence intervals for Cpm are obtained and are compared in terms of coverage probabilities, missed rate and average interval width.

Resistive indices in the evaluation of infants with obstructive and nonobstructive pyelocaliectasis

Diagnosing obstructive uropathy by renal resistive indices calculated from duplex Doppler sonographic waveforms has been supported as well as challenged in the radiology literature relating to adults. Despite reports of normally higher resistive indices in children as compared to adults, two studies have documented high sensitivity and specificity of renal Doppler sonography in the diagnosis of obstructive uropathy in children, using the same discriminatory criterion of a resistive index of 0.7 or greater as used in adults. We evaluated 43 infants with significant or bilateral pyelocaliectasis secondary to both obstructive and unobstructive uropathy and found no significant difference in the mean resistive indices or the mean difference in resistive indices of two kidneys in one patient. We conclude that Doppler sonography in infants has no value in differentiating obstructive from nonobstructive pyelocaliectasis.

Testing Significance of a Mean Vector - A Possible Alternative to Hotelling's T Squared.

In problems involving multivariate measurements experimental considerations often indicate grouping of variables into subsets ordered according to their importance. In such situations, the problems such as comparison of two mean vectors and profile analysis may be treated by HotellingsT2-test adapted along the lines of the step-wise procedure of J. Roy [10], or the well known test for additional information due to Rao [9]. In this paper we study a modification of the step-wise procedure obtained by combining the component tests. The exact Bahadur slopes of resulting procedures are computed and it is shown that the procedure based upon Fishers combination method is asymptotically equivalent to HotellingsT2. A Monte Carlo study suggests that even in small samples the power functions of the new method and HotellingsT2-test are practically equivalent.

Hepatic enhancement analysis in children using Smart Prep monitoring for 2 : 1 pitch helical scanning

Purpose. To analyze hepatic enhancement by using Smart Prep protocols appropriate for children of different weight groups and 2:1 pitch helical CT imaging as the investigative tools. Patients and methods. A group of 55 children ranging in weight between 20 and 180 lbs underwent 67 contrast-enhanced abdominal helical CT examinations using Smart Prep (GE Medical Systems, Milwaukee, Wisc.). Of these studies, 21 (31 %) were excluded because of failure to follow the prescribed Smart Prep protocols. Smart Prep protocols were established for nine different weight groups. Scan delay, aorta and liver time to peak, and liver enhancement over baseline were recorded. Results. Optimal abdominal CT studies with adequate contrast enhancement of hepatic and portal veins were obtained in 46 patients. There was no significant difference in the time between peak aortic and the liver enhancement among different weight groups (mean time 12.0 ± 7.1 s for all children). However, the mean hepatic enhancement over baseline in children weighing < 30 lbs was below 50 Hounsfield units (HU) compared to the rest of the children who had mean hepatic enhancement of > 50 HU. Conclusion. Two-thirds of the Smart Prep protocols were successfully implemented, and all of these resulted in good contrast enhancement of hepatic and portal veins. Optimal mean liver enhancement (> 50 HU) was seen in children ≥ 30 lbs. Children < 30 lbs had mean liver enhancement of 33 HU ± 7.2 above the baseline likely caused by contrast dose.

A Method for Identification of Some Components of Judging Springboard Diving

Abstract This article presents a method to analyze the scoring of judges in springboard diving by identifying some of the components of a dive which are useful in predicting the scores of the judges. A videotape recording of 26 divers doing the front dive half-twist was made at the 1979 mens A.A.U. prequalifying meet, held at Ohio State University. The method of measurement involved the use of clear plastic grids placed over the video monitor. The maximum height of the diver above the board, distance out from the board, size and duration of splash, numerous body angles at various times during the dive, as well as deviation of twist from 180 degrees were measured. A Stepwise Multiple Regression program was used to generate a prediction equation using a subset of these variables which would best predict the total score of the judges for each dive. The equation generated included height, distance, twist, and lower body angle at the point when the divers head was opposite the board; the equation predicted t...

Radiographic assessment of sacral screw placement

Sacral screw penetration of the anterior sacral cortex runs the risk of injury to neural, vascular, and visceral structures. This study examined the accuracy of the standard anteroposterior (AP) and lateral roentgenographic views as compared to a modified pelvic inlet (MPI) view in determining sacral screw penetration and angulation. Ten human cadaveric specimens were studied. Screw depth and screw angulation in the transverse plane were best evaluated with the MPI view. Screw penetration was overestimated by 0.4 mm (+/- 2.2 mm) on the MPI view, whereas the lateral view overestimated screw penetration by 2.8 mm (+/- 4.7 mm). Screw angulation in the sagittal plane could only be evaluated by the lateral view. The standard anteroposterior view provided little useful information on sacral screw orientation. To study all parameters of sacral screw placement, the radiographic series should include a modified pelvic inlet view and a lateral sacral view.