(Cd,Mg)Te crystals for picosecond-response optical-to-x-ray radiation detectors.

We demonstrate a photodetector sensitive to both optical and x-ray picosecond pulses based on our in-house grown cadmium magnesium telluride (Cd,Mg)Te single crystal. Specifically, we developed In-doped Cd0.96Mg0.04Te material and discuss its femtosecond optical photoresponse, as well as the detector performance, such as <100-pA dark current and up to 0.22-mA/W responsivity for 780-nm wavelength optical radiation. The detector exposed to Ti fluorescence (K alpha) x-ray pulses at 4.5 keV, generated by a free-electron laser beam with the central energy of 9.8 keV and <100 fs pulse width, exhibited readout-electronics-limited 200-ps full-width-at-half-maximum photoresponse, demonstrating that it is suitable for coarse timing in free-electron laser x-ray/optical femtosecond pump-probe spectroscopy applications.

Epidemiology, haematology and molecular characterization of haemoprotozoon and rickettsial organisms causing infections in cattle of Jammu region, North India.

BACKGROUND: The present study was aimed at establishing the prevalence, epidemiology and molecular characterization of major haemoprotozoons (Babesia and Theileria) and rickettsia (Anaplasma) of cattle in Jammu region (North India) using microscopy and Polymerase Chain Reaction (PCR). Hematology, microscopy and PCR based prevalence studies were undertaken with 278 whole blood samples from cattle. Molecular prevalence studies were followed by genetic characterization of the isolates of Babesia, Anaplasma and Theileria spp. based on 18S rRNA, 16S rRNA and Tams1 gene, respectively. The data related to metrology and epidemiological variables like temperature, rainfall, season, age and type of livestock rearing was analyzed and correlated with occurrence of disease by statistical methods. RESULTS: The prevalence based on microscopy was 12.9% (36/278) whereas PCR recorded 30.22% (84/278) animals positive for haemoparasitic infections. All the samples found positive by microscopy were also recorded positive by PCR. Thus the study revealed prevalence of Babesia bigemina, Anaplasma marginale and Theileria annulata to be 9.7, 16.5 and 0.7% respectively. The metrological and epidemiological variables made inroads for the propagation of vector ticks and occurrence of infection. Haematological alterations predominantly related to decrease in haemoglobin, red blood cell count and packed cell volume were evident in diseased animals and collaterally affected the productivity. Further the genetic characterization of Babesia bigemina. (MN566925.1, MN567603, MN566924.1), Anaplasma marginale. (MH733242.1, MN567602.1) and Theileria annulata (MT113479) provided a representative data of the isolates circulating in the region and their proximity with available sequences across the world. CONCLUSIONS: Despite holding much significance to the animal sector, comprehensive disease mapping has yet not been undertaken in several parts of India. The present study provides a blue print of disease mapping, epidemiological correlations and genomic diversity of Babesia bigemina, Anaplasma marginale and Theileria annulata circulating in the region.

Acceleration of cutaneous wound healing by Lucilia sericata maggots in diabetic Wistar rats.

The study was aimed to evaluate the effectiveness of maggot therapy in healing of cutaneous infected wound in streptozotocin (STZ) induced diabetic Wistar rat. For live maggots, the sterilized eggs of Lucilia sericata were obtained from colonies established in laboratory. Diabetes model was established in 48 male Wister rat by intra-peritoneal injection of STZ at the dose of 60 mg/kg body-weight. Cutaneous wounds exposed with mixed colonies of bacteria like Staphylococcus aureus, E. coli and Pseudomonas aeruginosa were prepared in all rat. The animals equally divided in 4 groups with 12 rats each being presented as treatment group of control, antibiotic, maggot and maggot with antibiotic in combination. All treatments were done once and hold for 24 hours. Wound kinetics and bacterial bio burden were measured at weekly interval to till complete healing. Significant reduction in wound area with maximum contraction was found (>95%) in maggot treated group when compared to antibiotic treated (79%) and control (72%). In maggot as well as maggot and antibiotic in combination group showed early elimination of bacterial bio-burden 7.88±0.03log CFU/ml to 1.12±0.65log CFU/ml and 7.86±0.04) log CFU/ml to 1.54±0.52log CFU/ml respectively in three weeks of time. Early healing indication was also experienced on histomorphological examination of wounded tissue of maggot treated groups by early and better epithelialization, collagenation and neovascularization with complete healing of wound in three weeks in comparison to antibiotic and control respectively. However, the present study did not show any difference in healing of wound with use of maggot alone or in antibiotic combination. Live maggot of Lucilia sericata effectively lower bacterial bioburden and and accelerate healing of infected cutaneous wound in diabetic conditions.

Seeking graduation in medical colleges outside India: Is it a 'win-win' or 'lose-lose' situation for the stakeholders and the nation?

The future of Indian students who return as 'foreign medical graduates' (FMG) after training in certain countries is often uncertain. We collected data from newspapers, government resources and agencies involved in handling this issue. We analysed the current status of medical education in India, the Commonwealth of Independent States (CIS) and some neighbouring countries. Of approximately 1.4 million (14 lakh) students taking the National Eligibility cum Entrance Test (NEET), about 5.8% get admission in medical colleges. There are about 554 medical colleges in India with 82 550 MBBS seats, 51.9% seats belong to the government quota. Parents who send their children to a foreign country to do medicine spend ₹1.5 million (15 lakh) tò4 million (40 lakh) against an estimated annual income of ₹1.2 million (12 lakh) and the child spends 4-6 years in a foreign country. Of 38 150 FMGs who took the examinations conducted by the National Board of Examinations from 2015 to 2018, 18.9% passed the FMG examination mandatory for registration to practise medicine in India. The National Medical Commission is trying to solve this issue by removing the age bar for entry to MBBS and recommending lowering of fees for MBBS in government quota. Seeking graduation in medical colleges outside India may not be advisable for those from the middle/ low-income group of India.

Next-Generation Nonlocal van der Waals Density Functional.

The fundamental ideas for a nonlocal density functional theory-capable of reliably capturing van der Waals interactions-were already conceived in the 1990s. In 2004, a seminal paper introduced the first practical nonlocal exchange-correlation functional called vdW-DF, which has become widely successful and laid the foundation for much further research. However, since then, the functional form of vdW-DF has remained unchanged. Several successful modifications paired the original functional with different (local) exchange functionals to improve performance, and the successor vdW-DF2 also updated one internal parameter. Bringing together different insights from almost 2 decades of development and testing, we present the next-generation nonlocal correlation functional called vdW-DF3, in which we change the functional form while staying true to the original design philosophy. Although many popular functionals show good performance around the binding separation of van der Waals complexes, they often result in significant errors at larger separations. With vdW-DF3, we address this problem by taking advantage of a recently uncovered and largely unconstrained degree of freedom within the vdW-DF framework that can be constrained through empirical input, making our functional semiempirical. For two different parameterizations, we benchmark vdW-DF3 against a large set of well-studied test cases and compare our results with the most popular functionals, finding good performance in general for a wide array of systems and a significant improvement in accuracy at larger separations. Finally, we discuss the achievable performance within the current vdW-DF framework, the flexibility in functional design offered by vdW-DF3, as well as possible future directions for nonlocal van der Waals density functional theory.

Automated ASPECTS on Noncontrast CT Scans in Patients with Acute Ischemic Stroke Using Machine Learning.

BACKGROUND AND PURPOSE: Alberta Stroke Program Early CT Score (ASPECTS) was devised as a systematic method to assess the extent of early ischemic change on noncontrast CT (NCCT) in patients with acute ischemic stroke (AIS). Our aim was to automate ASPECTS to objectively score NCCT of AIS patients. MATERIALS AND METHODS: We collected NCCT images with a 5-mm thickness of 257 patients with acute ischemic stroke (<8 hours from onset to scans) followed by a diffusion-weighted imaging acquisition within 1 hour. Expert ASPECTS readings on DWI were used as ground truth. Texture features were extracted from each ASPECTS region of the 157 training patient images to train a random forest classifier. The unseen 100 testing patient images were used to evaluate the performance of the trained classifier. Statistical analyses on the total ASPECTS and region-level ASPECTS were conducted. RESULTS: For the total ASPECTS of the unseen 100 patients, the intraclass correlation coefficient between the automated ASPECTS method and DWI ASPECTS scores of expert readings was 0.76 (95% confidence interval, 0.67-0.83) and the mean ASPECTS difference in the Bland-Altman plot was 0.3 (limits of agreement, -3.3, 2.6). Individual ASPECTS region-level analysis showed that our method yielded κ = 0.60, sensitivity of 66.2%, specificity of 91.8%, and area under curve of 0.79 for 100 × 10 ASPECTS regions. Additionally, when ASPECTS was dichotomized (>4 and ≤4), κ = 0.78, sensitivity of 97.8%, specificity of 80%, and area under the curve of 0.89 were generated between the proposed method and expert readings on DWI. CONCLUSIONS: The proposed automated ASPECTS scoring approach shows reasonable ability to determine ASPECTS on NCCT images in patients presenting with acute ischemic stroke.

Pseudo-spin skyrmions in the phase diagram of cuprate superconductors.

Topological states of matter are at the root of some of the most fascinating phenomena in condensed matter physics. Here we argue that skyrmions in the pseudo-spin space related to an emerging SU(2) symmetry enlighten many mysterious properties of the pseudogap phase in under-doped cuprates. We detail the role of the SU(2) symmetry in controlling the phase diagram of the cuprates, in particular how a cascade of phase transitions explains the arising of the pseudogap, superconducting and charge modulation phases seen at low temperature. We specify the structure of the charge modulations inside the vortex core below T c, as well as in a wide temperature region above T c, which is a signature of the skyrmion topological structure. We argue that the underlying SU(2) symmetry is the main structure controlling the emergent complexity of excitations at the pseudogap scale T *. The theory yields a gapping of a large part of the anti-nodal region of the Brillouin zone, along with q = 0 phase transitions, of both nematic and loop currents characters.

Therapeutic use of Lucilia sericata maggot in controlling bacterial bio-burden in Rat wound model.

Delayed wound healing due to extraneous bacterial contamination, antibacterial resistance and other associated factors are of great concern in dealing patients having chronically infected wound. Medicinal properties of certain maggots of Calliphoridae family are known for its effective wound debridement therapy. The objective of the study was to evaluate the wound healing potential of maggots of Lucilia sericata in an experimentally infected cutaneous wound model in Wistar rat. The study was carried out by using male Wistar rats (n=48) by creating excisional wounds and later contaminated with mixed population of gram positive and gram-negative bacteria. Animals were divided randomly in to four groups with 12 individuals each, being denominated as control, antibiotic treated, maggot treated, and antibiotic plus maggot combination treated group. Ten pre-sterilized maggots were applied per centimetre square wound bed for 24 hours. Different wound kinetics in L. sericata maggot treated wounds revealed significant reduction in wound area with maximum contraction, early elimination of bacterial bioburden as compared to group of infected control and group of rats receiving only antibiotic treatment. The histopathological examination of wounded tissue of maggot treated groups showed early and better epithelialization, collagenation and neovascularization with complete healing of wound in two weeks. The maggot effects on healing when used singly or in combination with antibiotic were recorded to be similar. The results of the present study clearly demonstrate that the maggots of L. sericata possesses a definite antibacterial action along with removal of dead tissues and effectively reduced the bacterial bio-burden in infected wound and induced wound healing quickly.

Alterations in oxidative stress parameters and its associated correlation with clinical disease on experimental Cryptosporidium parvum infection in Swiss albino mice.

The present study was conducted to evaluate the changes in oxidative stress parameters on experimental infection with Cryptosporidium parvum in Swiss albino mice. The mice were divided into four groups viz., group I-IV, each group comprising of 15 mice. Group I mice served as healthy control. In Group II mice, C. parvum oocysts @ 104/os were administered, mice of group III were given dexamethasone @ 30 µg/ml in drinking water whereas group IV mice were given dexamethasone @ 30 µg/ml along with C. parvum oocysts @ 104/os. Significant changes were seen in oxidative stress parameters which included significant increase in LPO and decrease in levels of SOD, CAT and GSH in liver and intestine in group IV mice at 10th DPI when compared to others indicating an important role played by free radical induced oxidative stress in the development of C. parvum infection in mice which was clinically characterized by loss of body condition, profuse bloody diarrhoea and peak oocyst shedding intensity occurring at 10th DPI.

Fibroblast growth factor receptor is a mechanistic link between visceral adiposity and cancer.

Epidemiological evidence implicates excess adipose tissue in increasing cancer risk. Despite a steeply rising global prevalence of obesity, how adiposity contributes to transformation (stage a non-tumorigenic cell undergoes to become malignant) is unknown. To determine the factors in adipose tissue that stimulate transformation, we used a novel ex vivo system of visceral adipose tissue (VAT)-condition medium-stimulated epithelial cell growth in soft agar. To extend this system in vivo, we used a murine lipectomy model of ultraviolet light B-induced, VAT-promoted skin tumor formation. We found that VAT from mice and obese human donors stimulated growth in soft agar of non-tumorigenic epithelial cells. The difference in VAT activity was associated with fibroblast growth factor-2 (FGF2) levels. Moreover, human and mouse VAT failed to stimulate growth in soft of agar in cells deficient in FGFR-1 (FGF2 receptor). We also demonstrated that circulating levels of FGF2 were associated with non-melanoma tumor formation in vivo. These data implicate FGF2 as a major factor VAT releases to transform epithelial cells-a novel, potential pathway of VAT-enhanced tumorigenesis. Strategies designed to deplete VAT stores of FGF2 or inhibit FGFR-1 in abdominally obese individuals may be important cancer prevention strategies as well as adjuvant therapies for improving outcomes.

Response of water deficit regime and soil amelioration on evapotranspiration loss and water use efficiency of maize (Zea mays l.) in subtropical northeastern Himalayas.

Rainfed maize production in the hilly ecosystem of Northeastern Himalayas often suffers from moisture and soil acidity induced abiotic stresses. The present study measured evapotranspiration loss (ETc) of maize crop under controlled condition (pot experiment) of water deficit (W25-25 % and W50-50 % of field capacity soil moistures) and well watered (W100 = 100 % of field capacity (FC)) regimes in strong acid soils (pH = 4.3) of the Northeastern Himalayan Region of India. The response of soil ameliorants (lime) and phosphorus (P) nutrition under differential water regimes on ETc losses and water use efficiency was also studied. The measured seasonal ETc loss varied from 124.3 to 270.9 mm across treatment combinations. Imposition of water deficit stress resulted in significant (p < 0.05) reduction (by 33-50 %) of seasonal ETc losses but was at the cost of delay in tasseling to silking, 47-65 % reduction in dry matter accumulation (DMA), 12-22 days shortening of grain formation period, and complete kernel abortion. Liming @ 4 t ha-1 significantly (p < 0.05) increased ETc losses and DMA across water regimes but the magnitude of increase was higher in severely water deficit (W25) regime. Unlike lime, P nutrition improved DMA only in well-watered regimes (W100) while seasonal ETc loss was unaffected. Vegetative stage (tillering to tasseling) contributed the maximum ETc losses while weekly crop ETc loss was estimated highest during 11th-14th week after sowing (coincided with blistering stage) and then declined. Water use efficiency estimated from dry matter produced per unit ETc losses and irrigation water used varied from 4.33 to 9.43 g dry matter kg-1 water and 4.21 to 8.56 g dry matter kg-1, respectively. Among the input factors (water, P, and lime), water regime most strongly influenced the ETc loss, growth duration, grain formation, and water use efficiency of maize.

Effect of reconstruction methods and x-ray tube current-time product on nodule detection in an anthropomorphic thorax phantom: A crossed-modality JAFROC observer study.

PURPOSE: To evaluate nodule detection in an anthropomorphic chest phantom in computed tomography (CT) images reconstructed with adaptive iterative dose reduction 3D (AIDR(3D)) and filtered back projection (FBP) over a range of tube current-time product (mAs). METHODS: Two phantoms were used in this study: (i) an anthropomorphic chest phantom was loaded with spherical simulated nodules of 5, 8, 10, and 12 mm in diameter and +100, -630, and -800 Hounsfield units electron density; this would generate CT images for the observer study; (ii) a whole-body dosimetry verification phantom was used to ultimately estimate effective dose and risk according to the model of the BEIR VII committee. Both phantoms were scanned over a mAs range (10, 20, 30, and 40), while all other acquisition parameters remained constant. Images were reconstructed with both AIDR(3D) and FBP. For the observer study, 34 normal cases (no nodules) and 34 abnormal cases (containing 1-3 nodules, mean 1.35 ± 0.54) were chosen. Eleven observers evaluated images from all mAs and reconstruction methods under the free-response paradigm. A crossed-modality jackknife alternative free-response operating characteristic (JAFROC) analysis method was developed for data analysis, averaging data over the two factors influencing nodule detection in this study: mAs and image reconstruction (AIDR(3D) or FBP). A Bonferroni correction was applied and the threshold for declaring significance was set at 0.025 to maintain the overall probability of Type I error at α = 0.05. Contrast-to-noise (CNR) was also measured for all nodules and evaluated by a linear least squares analysis. RESULTS: For random-reader fixed-case crossed-modality JAFROC analysis, there was no significant difference in nodule detection between AIDR(3D) and FBP when data were averaged over mAs [F(1, 10) = 0.08, p = 0.789]. However, when data were averaged over reconstruction methods, a significant difference was seen between multiple pairs of mAs settings [F(3, 30) = 15.96, p < 0.001]. Measurements of effective dose and effective risk showed the expected linear dependence on mAs. Nodule CNR was statistically higher for simulated nodules on images reconstructed with AIDR(3D) (p < 0.001). CONCLUSIONS: No significant difference in nodule detection performance was demonstrated between images reconstructed with FBP and AIDR(3D). mAs was found to influence nodule detection, though further work is required for dose optimization.

Greenhouse gases emission from soils under major crops in Northwest India.

Quantification of greenhouse gases (GHGs) emissions from agriculture is necessary to prepare the national inventories and to develop the mitigation strategies. Field experiments were conducted during 2008-2010 at the experimental farm of the Indian Agricultural Research Institute, New Delhi, India to quantify nitrous oxide (N2O), methane (CH4), and carbon dioxide (CO2) emissions from soils under cereals, pulses, millets, and oilseed crops. Total cumulative N2O emissions were significantly different (P>0.05) among the crop types. Emission of N2O as percentage of applied N was the highest in pulses (0.67%) followed by oilseeds (0.55%), millets (0.43%) and cereals (0.40%). The emission increased with increasing rate of N application (r(2)=0.74, P<0.05). The cumulative flux of CH4 from the rice crop was 28.64±4.40 kg ha(-1), while the mean seasonal integrated flux of CO2 from soils ranged from 3058±236 to 3616±157 kg CO2 ha(-1) under different crops. The global warming potential (GWP) of crops varied between 3053 kg CO2 eq. ha(-1) (pigeon pea) and 3968 kg CO2 eq. ha(-1) (wheat). The carbon equivalent emission (CEE) was least in pigeon pea (833 kg C ha(-1)) and largest in wheat (1042 kg C ha(-1)). The GWP per unit of economic yield was the highest in pulses and the lowest in cereal crops. The uncertainties in emission values varied from 4.6 to 22.0%. These emission values will be useful in updating the GHGs emission inventory of Indian agriculture.

Mammography test sets: reading location and prior images do not affect group performance.

AIM: To examine how the location where reading takes place and the availability of prior images can affect performance in breast test-set reading. MATERIALS AND METHODS: Under optimized viewing conditions, 10 expert screen readers each interpreted a reader-specific set of images containing 200 mammographic cases. Readers, randomly divided into two groups read images under one of two pairs of conditions: clinical read with prior images and laboratory read with prior images; laboratory read with prior images and laboratory read without prior images. Region-of-interest (ROI) figure-of-merit (FOM) was analysed using JAFROC software. Breast side-specific sensitivity and specificity were tested using Wilcoxon matched-pairs signed rank tests. Agreement between pairs of readings was measured using Kendall's coefficient of concordance. RESULTS: Group performances between test-set readings demonstrated similar ROI FOMs, sensitivity and specificity median values, and acceptable levels of agreement between pairs of readings were shown (W = 0.75-0.79, p < 0.001) for both pairs of reading conditions. On an individual reader level, two readers demonstrated significant decreases (p < 0.05) in ROI FOMs when prior images were unavailable. Reading location had an inconsistent impact on individual performance. CONCLUSION: Reading location and availability of prior images did not significantly alter group performance.

On the choice of acceptance radius in free-response observer performance studies.

OBJECTIVES: Choosing an acceptance radius or proximity criterion is necessary to analyse free-response receiver operating characteristic (FROC) observer performance data. This is currently subjective, with little guidance in the literature about what is an appropriate acceptance radius. We evaluated varying acceptance radii in a nodule detection task in chest radiography and suggest guidelines for determining an acceptance radius. METHODS: 80 chest radiographs were chosen, half of which contained nodules. We determined each nodule's centre. 21 radiologists read the images. We created acceptance radii bins of <5 pixels, <10 pixels, <20 pixels and onwards up to <200 and 200+ pixels. We counted lesion localisations in each bin and visually compared marks with the borders of nodules. RESULTS: Most reader marks were tightly clustered around nodule centres, with tighter clustering for smaller than for larger nodules. At least 70% of readers' marks were placed within <10 pixels for small nodules, <20 pixels for medium nodules and <30 pixels for large nodules. Of 72 inspected marks that were less than 50 pixels from the centre of a nodule, only 1 fell outside the border of a nodule. CONCLUSION: The acceptance radius should be based on the larger nodule sizes. For our data, an acceptance radius of 50 pixels would have captured all but 2 reader marks within the borders of a nodule, while excluding only 1 true-positive mark. The choice of an acceptance radius for FROC analysis of observer performance studies should be based on the size of larger abnormalities.

Persistence of a Brownian particle in a time-dependent potential.

We investigate the persistence probability of a Brownian particle in a harmonic potential, which decays to zero at long times, leading to an unbounded motion of the Brownian particle. We consider two functional forms for the decay of the confinement, an exponential decay and an algebraic decay. Analytical calculations and numerical simulations show that for the case of the exponential relaxation, the dynamics of Brownian particle at short and long times are independent of the parameters of the relaxation. On the contrary, for the algebraic decay of the confinement, the dynamics at long times is determined by the exponent of the decay. Finally, using the two-time correlation function for the position of the Brownian particle, we construct the persistence probability for the Brownian walker in such a scenario.

Dysregulation of DGCR6 and DGCR6L: psychopathological outcomes in chromosome 22q11.2 deletion syndrome.

Chromosome 22q11.2 deletion syndrome (22q11DS) is the most common microdeletion syndrome in humans. It is typified by highly variable symptoms, which might be explained by epigenetic regulation of genes in the interval. Using computational algorithms, our laboratory previously predicted that DiGeorge critical region 6 (DGCR6), which lies within the deletion interval, is imprinted in humans. Expression and epigenetic regulation of this gene have not, however, been examined in 22q11DS subjects. The purpose of this study was to determine if the expression levels of DGCR6 and its duplicate copy DGCR6L in 22q11DS subjects are associated with the parent-of-origin of the deletion and childhood psychopathologies. Our investigation showed no evidence of parent-of-origin-related differences in expression of both DGCR6 and DGCR6L. However, we found that the variability in DGCR6 expression was significantly greater in 22q11DS children than in age and gender-matched control individuals. Children with 22q11DS who had anxiety disorders had significantly lower DGCR6 expression, especially in subjects with the deletion on the maternal chromosome, despite the lack of imprinting. Our findings indicate that epigenetic mechanisms other than imprinting contribute to the dysregulation of these genes and the associated childhood psychopathologies observed in individuals with 22q11DS. Further studies are now needed to test the usefulness of DGCR6 and DGCR6L expression and alterations in the epigenome at these loci in predicting childhood anxiety and associated adult-onset pathologies in 22q11DS subjects.

Breast tomosynthesis and digital mammography: a comparison of diagnostic accuracy.

OBJECTIVE: Our aim was to compare the ability of radiologists to detect breast cancers using one-view breast tomosynthesis (BT) and two-view digital mammography (DM) in an enriched population of diseased patients and benign and/or healthy patients. METHODS: All participants gave informed consent. The BT and DM examinations were performed with about the same average glandular dose to the breast. The study population comprised patients with subtle signs of malignancy seen on DM and/or ultrasonography. Ground truth was established by pathology, needle biopsy and/or by 1-year follow-up by mammography, which retrospectively resulted in 89 diseased breasts (1 breast per patient) with 95 malignant lesions and 96 healthy or benign breasts. Two experienced radiologists, who were not participants in the study, determined the locations of the malignant lesions. Five radiologists, experienced in mammography, interpreted the cases independently in a free-response study. The data were analysed by the receiver operating characteristic (ROC) and jackknife alternative free-response ROC (JAFROC) methods, regarding both readers and cases as random effects. RESULTS: The diagnostic accuracy of BT was significantly better than that of DM (JAFROC: p=0.0031, ROC: p=0.0415). The average sensitivity of BT was higher than that of DM (∼90% vs ∼79%; 95% confidence interval of difference: 0.036, 0.108) while the average false-positive fraction was not significantly different (95% confidence interval of difference: -0.117, 0.010). CONCLUSION: The diagnostic accuracy of BT was superior to DM in an enriched population.

Quantifying the clinical relevance of a laboratory observer performance paradigm.

OBJECTIVE: Laboratory observer performance measurements, receiver operating characteristic (ROC) and free-response ROC (FROC) differ from actual clinical interpretations in several respects, which could compromise their clinical relevance. The objective of this study was to develop a method for quantifying the clinical relevance of a laboratory paradigm and apply it to compare the ROC and FROC paradigms in a nodule detection task. METHODS: The original prospective interpretations of 80 digital chest radiographs were classified by the truth panel as correct (C=1) or incorrect (C=0), depending on correlation with additional imaging, and the average of C was interpreted as the clinical figure of merit. FROC data were acquired for 21 radiologists and ROC data were inferred using the highest ratings. The areas under the ROC and alternative FROC curves were used as laboratory figures of merit. Bootstrap analysis was conducted to estimate conventional agreement measures between laboratory and clinical figures of merit. Also computed was a pseudovalue-based image-level correctness measure of the laboratory interpretations, whose association with C as measured by the area (rAUC) under an appropriately defined relevance ROC curve, is as a measure of the clinical relevance of a laboratory paradigm. RESULTS: Low correlations (e.g. κ=0.244) and near chance level rAUC values (e.g. 0.598), attributable to differences between the clinical and laboratory paradigms, were observed. The absolute width of the confidence interval was 0.38 for the interparadigm differences of the conventional measures and 0.14 for the difference of the rAUCs. CONCLUSION: The rAUC measure was consistent with the traditional measures but was more sensitive to the differences in clinical relevance. A new relevance ROC method for quantifying the clinical relevance of a laboratory paradigm is proposed.

Rat placentation: an experimental model for investigating the hemochorial maternal-fetal interface.

The rat possesses hemochorial placentation with deep intrauterine trophoblast cell invasion and trophoblast-directed uterine spiral artery remodeling; features shared with human placentation. Recognition of these similarities spurred the establishment of in vitro and in vivo research methods using the rat as an animal model to address mechanistic questions regarding development of the hemochorial placenta. The purpose of this review is to provide the requisite background to help move the rat to the forefront in placentation research.