Estimating body volumes and surface areas of animals from cross-sections.

Background: Body mass and surface area are among the most important biological properties, but such information is lacking for some extant organisms and most extinct species. Numerous methods have been developed for body size estimation of animals for this reason. There are two main categories of mass-estimating approaches: extant-scaling approaches and volumetric-density approaches. Extant-scaling approaches determine the relationships between linear skeletal measurements and body mass using regression equations. Volumetric-density approaches, on the other hand, are all based on models. The models are of various types, including physical models, 2D images, and 3D virtual reconstructions. Once the models are constructed, their volumes are acquired using Archimedes' Principle, math formulae, or 3D software. Then densities are assigned to convert volumes to masses. The acquisition of surface area is similar to volume estimation by changing math formulae or software commands. This article presents a new 2D volumetric-density approach called the cross-sectional method (CSM). Methods: The CSM integrates biological cross-sections to estimate volume and surface area accurately. It requires a side view or dorsal/ventral view image, a series of cross-sectional silhouettes and some measurements to perform the calculation. To evaluate the performance of the CSM, two other 2D volumetric-density approaches (Graphic Double Integration (GDI) and Paleomass) are compared with it. Results: The CSM produces very accurate results, with average error rates around 0.20% in volume and 1.21% in area respectively. It has higher accuracy than GDI or Paleomass in estimating the volumes and areas of irregular-shaped biological structures. Discussion: Most previous 2D volumetric-density approaches assume an elliptical or superelliptical approximation of animal cross-sections. Such an approximation does not always have good performance. The CSM processes the true profiles directly rather than approximating and can deal with any shape. It can process objects that have gradually changing cross-sections. This study also suggests that more attention should be paid to the careful acquisition of cross-sections of animals in 2D volumetric-density approaches, otherwise serious errors may be introduced during the estimations. Combined with 2D modeling techniques, the CSM can be considered as an alternative to 3D modeling under certain conditions. It can reduce the complexity of making reconstructions while ensuring the reliability of the results.

Ultrahigh and Durable Volumetric Lithium/Sodium Storage Enabled by a Highly Dense Graphene-Encapsulated Nitrogen-Doped Carbon@Sn Compact Monolith.

Tin-based composites hold promise as anodes for high-capacity lithium/sodium-ion batteries (LIBs/SIBs); however, it is necessary to use carbon coated nanosized tin to solve the issues related to large volume changes during electrochemical cycling, thus leading to the low volumetric capacity for tin-based composites due to their low packing density. Herein, we design a highly dense graphene-encapsulated nitrogen-doped carbon@Sn (HD N-C@Sn/G) compact monolith with Sn nanoparticles double-encapsulated by N-C and graphene, which exhibits a high density of 2.6 g cm-3 and a high conductivity of 212 S m-1. The as-obtained HD N-C@Sn/G monolith anode exhibits ultrahigh and durable volumetric lithium/sodium storage. Specifically, it delivers a high volumetric capacity of 2692 mAh cm-3 after 100 cycles at 0.1 A g-1 and an ultralong cycling stability exceeding 1500 cycles at 1.0 A g-1 with only 0.019% capacity decay per cycle in lithium-ion batteries. Besides, in situ TEM and ex situ SEM have revealed that the unique double-encapsulated structure effectively mitigates drastic volume variation of the tin nanoparticles during electrode cycling. Furthermore, the full cell using HD N-C@Sn/G as an anode and LiCoO2 as a cathode displays a superior cycling stability. This work provides a new avenue and deep insight into the design of high-volumetric-capacity alloy-based anodes with ultralong cycle life.

Impaired geometry, volumetric density, and microstructure of cortical and trabecular bone assessed by HR-pQCT in both sporadic and MEN1-related primary hyperparathyroidism.

This study evaluated bone features of PHPT using HR-pQCT. The results showed both cortical and trabecular bones were significantly impaired in PHPT patients. Male and female PHPT patients suffered similar damages in bone. HR-pQCT indices were not observed to differ in MEN1 and sporadic PHPT patients. INTRODUCTION: High-resolution peripheral quantitative CT is a novel imaging technique used to separately assess trabecular and cortical bone status of the radius and tibia in vivo. Using HR-pQCT, we aimed to evaluate bone features of primary hyperparathyroidism patients in a Chinese population and reveal similarities and differences in bone features in multiple endocrine neoplasia type 1-related PHPT and sporadic PHPT patients in the Chinese population. METHODS: A case-control study was designed. In 58 PHPT patients and 58 sex- and age-matched healthy controls, the distal radius and tibia were scanned using HR-pQCT. Areal bone mineral density (aBMD) was also determined in PHPT patients using dual-energy X-ray absorptiometry (DXA). RESULTS: In comparison with controls, PHPT patients were observed to exhibit reduced volumetric BMD at the cortical and trabecular compartments, thinner cortices, and more widely spaced trabeculae. Significant differences were still observed when comparing data of female and male patients with age-matched controls separately. MHPT patients (n = 11) were found to have lower aBMD Z-scores in the lumbar spine, trochanteric region, and total hip compared with sporadic PHPT patients (n = 47), while no differences were observed in HR-pQCT indices between the two groups. In multiple linear regression models, no significant correlations were identified between PTH and HR-pQCT indices. However, height was found to positively correlate with HR-pQCT-derived trabecular indices at both the radius and tibia. CONCLUSIONS: PHPT affects geometry, volumetric density, and microstructure in both the cortical and trabecular bones in both male and female Chinese patients. MHPT patients were observed to have reduced aBMD as determined by DXA in the lumbar spine and hip in comparison with sporadic PHPT patients. However, HR-pQCT indices were not observed to differ.

Quantitative Computed Tomography (QCT) of the Distal Forearm in Men Using a Spiral Whole-Body CT Scanner - Description of a Method and Reliability Assessment of the QCT Pro Software.

The Mr F study investigates the pathogenesis of low trauma distal forearm fractures in men and includes volumetric bone mineral density (vBMD) measurements at the ultradistal forearm as there are no current data. A standard 64 slice CT scanner was used to determine if it was possible to adapt the existing Mindways quantitative computed tomography Pro software for measuring vBMD values at the hip and spine sites. For calculation of intra- and interobserver reliability 40 forearm scans out of the 300 available were chosen randomly. The images were analyzed using the Slice Pick module and Bone Investigational Toolkit. The 4% length of the radius was chosen by measuring the length of the radius from the scaphoid fossa distally to the radial head. The acquired image then underwent extraction, isolation, rotation, and selection of region of interest in order to generate a report on vBMD. A cross-sectional image was created to allow the generation of data on the cortical and trabecular components separately. Repeat analyses were undertaken by 3 independent observers who were blinded as to whether the image was from a participant with or without fracture. The images were presented in random order at each time point. The following parameters were recorded: cortical cross sectional area, total vBMD, trabecular vBMD, and cortical vBMD (CvBMD). Data were analyzed by calculating intraclass correlation coefficients for intra- and interobserver reliability. The lowest values occurred at the CvBMD with intraobserver reliability of 0.92 (95% confidence interval [CI] of 0.86-0.96) and interobserver reliability of 0.92 (95% CI 0.89-0.96). All other parameters had reliability values between 0.97 and 0.99 with tighter 95% CI than for CvBMD. The method of adapting the Mindways Pro software using a standard CT to produce vBMD and structural data at the ultradistal radius is reliable.

Automated volumetric breast density measures: differential change between breasts in women with and without breast cancer.

BACKGROUND: Given that breast cancer and normal dense fibroglandular tissue have similar radiographic attenuation, we examine whether automated volumetric density measures identify a differential change between breasts in women with cancer and compare to healthy controls. METHODS: Eligible cases (n = 1160) had unilateral invasive breast cancer and bilateral full-field digital mammograms (FFDMs) at two time points: within 2 months and 1-5 years before diagnosis. Controls (n = 2360) were matched to cases on age and date of FFDMs. Dense volume (DV) and volumetric percent density (VPD) for each breast were assessed using Volpara™. Differences in DV and VPD between mammograms (median 3 years apart) were calculated per breast separately for cases and controls and their difference evaluated by using the Wilcoxon signed-rank test. To simulate clinical practice where cancer laterality is unknown, we examined whether the absolute difference between breasts can discriminate cases from controls using area under the ROC curve (AUC) analysis, adjusting for age, BMI, and time. RESULTS: Among cases, the VPD and DV between mammograms of the cancerous breast decreased to a lesser degree (- 0.26% and - 2.10 cm3) than the normal breast (- 0.39% and - 2.74 cm3) for a difference of 0.13% (p value < 0.001) and 0.63 cm3 (p = 0.002), respectively. Among controls, the differences between breasts were nearly identical for VPD (- 0.02 [p = 0.92]) and DV (0.05 [p = 0.77]). The AUC for discriminating cases from controls using absolute difference between breasts was 0.54 (95% CI 0.52, 0.56) for VPD and 0.56 (95% CI, 0.54, 0.58) for DV. CONCLUSION: There is a small relative increase in volumetric density measures over time in the breast with cancer which is not found in the normal breast. However, the magnitude of this difference is small, and this measure alone does not appear to be a good discriminator between women with and without breast cancer.

Novel Non-Carbon Sulfur Hosts Based on Strong Chemisorption for Lithium-Sulfur Batteries.

Lithium-sulfur (Li-S) batteries are considered as promising candidates for energy storage systems owing to their high theoretical capacity and high energy density. The application of Li-S batteries is hindered by several obstacles, however, including the shuttle effect, poor electrical conductivity, and the severe volume expansion of sulfur. The traditional method is to integrate sulfur with carbon materials. But the interaction between polysulfide intermediates and carbon is only weak physical adsorption, which easily leads to the escape of species from the framework (shuttle effect) of the material causing capacity loss. Recently, however, there has been a trend for the introduction of novel non-carbon materials as sulfur hosts based on the strong chemisorption. This review highlights recent research progress on novel non-carbon sulfur hosts based on strong chemisorption, in Li-S batteries. In comparison with carbon-based sulfur hosts, most non-carbon sulfur hosts have been demonstrated to be polar host materials that could efficiently adsorb polysulfide via strong chemisorption, mitigating their dissolution. The intrinsic mechanism associated with the role of non-carbon-based host materials in improving the performance of Li-S batteries is discussed.

Lepidic Predominant Pulmonary Lesions (LPL): CT-based Distinction From More Invasive Adenocarcinomas Using 3D Volumetric Density and First-order CT Texture Analysis.

RATIONALE AND OBJECTIVES: This study aimed to differentiate pathologically defined lepidic predominant lesions (LPL) from more invasive adenocarcinomas (INV) using three-dimensional (3D) volumetric density and first-order texture histogram analysis of surgically excised stage 1 lung adenocarcinomas. MATERIALS AND METHODS: This retrospective study was institutional review board approved and Health Insurance Portability and Accountability Act compliant. Sixty-four cases of pathologically proven stage 1 lung adenocarcinoma surgically resected between September 2006 and October 2015, including LPL (n = 43) and INV (n = 21), were evaluated using high-resolution computed tomography. Quantitative measurements included nodule volume, percent solid volume (% solid), and first-order texture histogram analysis including skewness, kurtosis, entropy, and mean nodule attenuation within each histogram quartile. Binomial logistic regression models were used to identify the best set of parameters distinguishing LPL from INV. RESULTS: Univariate analysis of 3D volumetric density and histogram features was statistically significant between LPL and INV groups (P < .05). Accuracy of a binomial logistic model to discriminate LPL from INV based on size and % solid was 85.9%. With optimized probability cutoff, the model achieves 81% sensitivity, 76.7% specificity, and area under the receiver operating characteristic curve of 0.897 (95% confidence interval, 0.821-0.973). An additional model based on size and mean nodule attenuation of the third quartile (Hu_Q3) of the histogram achieved similar accuracy of 81.3% and area under the receiver operating characteristic curve of 0.877 (95% confidence interval, 0.790-0.964). CONCLUSIONS: Both 3D volumetric density and first-order texture analysis of stage 1 lung adenocarcinoma allow differentiation of LPL from more invasive adenocarcinoma with overall accuracy of 85.9%-81.3%, based on multivariate analyses of either size and % solid or size and Hu_Q3, respectively.

Densidad ósea volumétrica vertebral obtenida sin fantoma en estudios de rutina de tomografía computarizada de abdomen: correlación con los valores medidos por densitometría ósea areal por rayos X / Phantom-less volumetric vertebral density obtained from routine abdominal ct studies: correlation with data obtained by DXA

La densidad mineral ósea (DMO) por tomografía computarizada cuantitativa (QCT) mide con exactitud y precisión de corto plazo la densidad volumétrica (DMOv) de secciones axiales de los cuerpos vertebrales lumbares valiéndose de un fantoma de calibración. Existe evidencia de que la densitometría por TC sin fantoma convirtiendo las unidades Hounsfield en g/cm3 aplicando un coeficiente específico para cada equipo, presenta muy alta correlación con la DMO por QCT y que es confiable para evaluar la densidad ósea vertebral. Apoyándonos en ello, correlacionamos DMO y CMO estimados a partir de estudios de TC con los obtenidos por DXA. Se incluyeron 28 mujeres (edad: 63,4±10,3 años, rango: 37-85) que habían realizado una TC de abdomen y previamente una DMO en un lapso previo no mayor de 6 meses. Se midieron: 1) TC: DMOv promedio integral (trabecular + cortical) en un corte axial medio vertebral de 10 mm de espesor y el área en cm2 . Se multiplicó la densidad por el área, obteniendo un valor equivalente al CMO de la sección (CMO-TC) y 2) DXA: se consideraron la DMOa y CMO en una RI de 10 mm de altura a nivel del centro de la vértebra L3. Las correlaciones entre los parámetros homólogos obtenidos por ambos métodos fueron significativas: resultó superior para CMO [DMOv vs. DMOa r: 0,67 (p=0,005) y CMO-TC vs. CMO-DXA r: 0,75 (p=0,00063)]. El estudio complementa los ya existentes y abre la posibilidad de utilizar estudios de rutina de TC de abdomen para evaluar la densidad ósea, para lo cual deberán establecerse valores de referencia sexo y edad específicos. (AU)

Conventional quantitative computed tomography (QCT) uses a calibration phantom scanned simultaneously with the anatomical region of interest and measures bone density accurately and with short-term high precision. Evidence supports that phantom-less volumetric BMD highly correlates with QCT BMD and is a reliable method for assessing bone density of vertebral bodies. Assessment of BMD in routine abdominal CT scans has been investigated in recent years. The aim of the study was to correlate BMD and bone mineral content (BMC) obtained from CT studies with data obtained by DXA. Twenty eight women (age 63.4±10.3 years old, range: 37-85) who underwent abdominal CT for different reasons and DXA measurements within 6 months were included. A simple manual region of interest (RI) which delineated the edge of the vertebral body was applied to L3. We measured 1) CT: Volumetric integral density (BMDv) -trabecular and cortical bone- of the axial section and area (A) in cm2 . Density was multiplied by area to obtain a value equivalent to BMC. 2) DXA: BMD and BMC in a RI of 10 mm height in the middle of L3. All parameters obtained by CT correlated significantly with the corresponding to DXA : BMDv vs BMDa r: 0.67 (p=0.005) y BMC-CT vs BMC-DXA: r: 0.75 (p=0.00063). This study complements previous reports and opens the possibility of using routine abdominal CT studies to assess bone density. For that purpose reference values (age and gender) must be established. (AU)