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Objective: To develop Z scores for the trachea and main bronchi in normal fetuses.Methods: This was a prospective cross-sectional study in 823 normal singleton fetuses. The tracheal diameter immediately proximal to the bifurcation and the left and right main bronchial diameters were measured from their inner to inner edge in the coronal view. Z scores were created for the trachea and main bronchial diameters using gestational age (GA), femur length (FL), and biparietal diameter (BPD) as independent variables.Results: Between gestational weeks 20 and 40, the inner diameters of the trachea, left principal bronchi (LPB), and right principal bronchi (RPB) increased from 1.8 to 4.7 mm, 0.8 to 2.2 mm, and 0.9 to 2.3 mm, respectively. A simple linear regression equation was fitted to model the mean of each diameter. There was however significant heteroscedasticity of the standard deviation (SD) with increasing GA, FL, or BPD. Eventually, the following formula was used to calculate Z scores for the diameters: [measured value - equation for mean]/equation for SD.Conclusion: We have developed Z scores for the fetal trachea and main bronchi by applying standard statistical methods. These Z scores may be useful to evaluate the early development of the respiratory system. [ABSTRACT FROM AUTHOR]

In this study, we select 18 SG (superconducting gravimeter) records from 15 GGP stations and 99 vertical, 69 horizontal components of IRIS broad-band seismograms during 2004 Sumatra Earthquake to detect the splitting of higher-degree Earth's free oscillations modes (0S4, 0S7~0S10, 2S4, 1S5, 2S5, 1S6) and 12 inner-core sensitive modes (25S2, 27S2, 6S3, 9S3, 13S3, 15S3, 11S4, 18S4, 8S5, 11S5, 23S5, 16S6) by using OSE (optimal sequence estimation) method which only considers self-coupling. Results indicate that OSE can completely isolate singlets of high-degree modes in time-domain, effectively resolve the coupled multiplets independently, and reduce the possibility of mode mixing and end effect, showing that OSE could improve some signals' signal-to-noise ratio. Comparing the results of SG records with seismic data sets suggests that the number of SG records is inadequate to detect all singlets of higher modes. Hence we mainly select plentiful seismograms of IRIS to observe the multiplets of higher modes. We estimate frequencies of the singlets using AR method and evaluate the measurement error using bootstrap method. Besides, we compared the observations with the predictions of PREM-tidal model. This study demonstrates that OSE is effective in isolating singlets of Earth's free oscillations with higher modes. The experimental results may provide constraints to the construction of 3D Earth model. [ABSTRACT FROM AUTHOR]

Returning precious fissile materials containing 235U, obtained from regenerated uranium, to the nuclear fuel cycle is important for the production of sustainable nuclear energy. Herein, starting from the basic single cascade separation scheme, schemes for enriching regenerated uranium are developed to satisfy the requirements for low-enriched uranium with a commercial grade and several supplementary separation conditions to the greatest extent for different considerations involving the consumption of natural uranium, scale of separation cascade, and material recovery. Double- and triple-cascade schemes are derived from the consideration of improving the basic scheme by eliminating its drawbacks such as the contamination of the entire cascade by artificial nuclides. All schemes are optimized based on a Q-model cascade and are compared. The results demonstrate that the triple-cascade scheme exhibits a good separation performance and may be a good choice among the existing schemes. However, the concentration of 235U in this scheme exceeds the limitation specified by the international standard for handling fissile materials; therefore, this scheme requires further improvement. • Multi-cascade separation schemes are developed for regenerated uranium separation. • Conditions for concentrations, material recovery and closed fuel cycle are considered. • All schemes are optimized and compared based on their optimal results. • A triple cascade scheme with good separation performance is obtained. • The method of scheme development can be followed to develop new schemes. [ABSTRACT FROM AUTHOR]

The Q-cascade is a type of model cascade that is particularly useful for studying multicomponent isotope separation. The cascade segmentation technique is further developed to optimize Q-cascades, which minimizes the relative total flow by splitting a cascade into smaller segments that each use the mass number of the virtual component as a decision variable. Application of this technique to Cadmium isotope separation shows that it is always effective. If the number of segments into which a cascade is split increases, then the minimum relative total flow decreases. A progressive segmentation strategy is developed to maximize the number of segments. [ABSTRACT FROM PUBLISHER]

Aim This study represents the first attempt to use ' Z-scores' to assess levator hiatal dimensions and quantify hiatal expansion. Methods We undertook a retrospective study on the data of 110 nulliparae and 73 pelvic organ prolapse (POP) patients who had a clinical POP exam and translabial 4-D ultrasound. We used Z-scores to normalize the dimensions of nulliparae levator hiatus and to build a Z-score model to evaluate the 'hiatal ballooning' against the POP staging. Results Valid data were gathered from 102 nulliparae and 64 POP patients. We built the Z-score models as follows: Z-Av = (measured value - 17.19) / 2.98, Z-Lv = (measured value - 55.65) / 5.48, where 'Av' and 'Lv' represented the 'hiatal area' and the 'anterior-posterior diameter' on Valsalva, respectively. The '90% reference range' of Z-Av was (−1.8−+1.8) and that of Z-Lv was (−2.0−+2.0). On receiver-operator curve analysis, the cut-off against POP stage 2 for Av was 20 cm2 (sensitivity of 79%, specificity of 66%), and that for Lv was 6.0 cm (sensitivity of 68%, specificity of 65%), which were approximately equal to a Z-Av of 1.0 and a Z-Lv of 1.0, correspondingly. For POP stage 3, the cut-off was an Av of 24 cm2 (sensitivity of 85%, specificity of 83%) or an anterior-posterior diameter of 6.3 cm (sensitivity of 77%, specificity of 80%), which was approximately equal to a Z-Av of 2.0 or a Z-Lv of 1.5, respectively. Conclusion 'Normal hiatal dimension' was defined as Z-Av ≤ 1.0 or Z-Lv ≤ 1.0, and 'hiatal ballooning' was defined as Z-Av ≥ 2.0 or Z-Lv ≥ 1.5. [ABSTRACT FROM AUTHOR]

Background: To investigate the differences in cardiovascular disease, extracardiac anomalies and outcomes between fetuses with levocardia and dextrocardia.Methods: Clinical demographics, prenatal features, postnatal characteristics and the outcomes of fetuses with levocardia or dextrocardia were recorded and analyzed.Results: Sixty-five fetuses with dextrocardia and thirty-eight fetuses with levocardia were enrolled. Right ventricle outlet obstruction, atrioventricular septal defect and intestinal malrotation were common in both groups. Univentricular physiology, transposition of the great arteries and esophageal atresia were more frequent in fetuses with levocardia, whereas abnormal pulmonary venous connection, double outlet of right ventricle, left ventricle outlet obstruction and brain abnormalities were more frequent in the dextrocardia group. The accuracy of evaluating cardiac malformations was high, but the sensitivity in assessing extracardiac abnormalities was low.Conclusions: Although the disorders have certain overlapping features, there are several differences between fetuses with levocardia and dextrocardia. These findings might improve patient counseling and perinatal management. [ABSTRACT FROM AUTHOR]

The splitting and coupling observations for the normal modes may reveal details about large-scale structure of the 3D Earth. In the frequency domain, especially for frequency >1.5 mHz, the mode-coupling should be taken into account as the modes become denser and closer. There are many S-S type clusters below 3 mHz which need to be resolved, such as 0 S 7 - 2 S 3 , 1 S 5 - 2 S 4 , 4 S 1 - 0 S 8 - 3 S 3 , 0 S 9 - 1 S 0 , 1 S 7 - 2 S 6 and other similar clusters. This paper explores whether the obtained splitting singlets of normal modes in high frequency band have higher SNRs and precision under the condition of considering coupling effects into the optimum sequence estimate (OSE). On the basis of the OSE method, we started experiments by extending the equations for vertical and transverse components to the group-coupling scheme that the splitting coefficient matrix B is not only determined by a target multiplet alone but also includes several cross-coupling multiplets. Then the results of self-coupling and group-coupling of the singlets are compared to determine whether the across-multiplet coupling plays an important role in the stripping of the modes. The results showed that the singlets of higher modes could be observed more clearly and resolved more completely by considering group-coupled modes for the narrow-band frequency. After comparing observations with predictions of the PREM−tidal model, the differences may provide valuable information about the deep Earth and further constraints on the 3D structure of the Earth. [ABSTRACT FROM AUTHOR]