Incremental diagnostic value of virtual non-contrast dual-energy CT for the diagnosis of choledocholithiasis over conventional unenhanced CT.

PURPOSE: The purpose of this study was to evaluate the incremental diagnostic value of virtual non-contrast (VNC) images derived from unenhanced dual-energy computed tomography (CT) for the diagnosis of choledocholithiasis by comparison with conventional unenhanced CT. MATERIALS AND METHODS: Eighty-nine patients with gallbladder stones who had undergone both abdominal unenhanced dual-energy CT and magnetic resonance cholangiopancreatography (MRCP) were retrospectively included. There were 53 men and 36 women, with a mean age of 54 ± 13 (standard deviation) years (age range: 41-67 years). VNC and conventional CT images were generated. Two independent radiologists evaluated the presence of choledocholithiasis in three reading sessions (session 1, conventional unenhanced CT images; session 2, VNC images; session 3, conventional unenhanced CT plus VNC images). The reading time to identify choledocholithiasis was recorded. Inter-reader agreement was measured by using the Cohen kappa (κ) test. Incremental diagnostic value of VNC imaging when combined with conventional unenhanced CT was assessed based on discrimination (area under the curve [AUC]) and clinical utility (decision curve analysis). The diagnostic performance of dual-energy CT and that of MRCP were compared using DeLong test. RESULTS: Using the standard of reference, 39 patients (39/89; 44%) had choledocholithiasis. The diagnosis of choledocholithiasis was improved using VNC images in combination with conventional unenhanced CT (AUC, 0.877; 95% confidence interval [CI]: 0.808, 0.947) by comparison with conventional unenhanced CT alone (AUC, 0.789; 95% CI: 0.718, 0.877) (P = 0.033) and achieved almost perfect inter-reader agreement (κ = 0.88; 95% CI: 0.72, 1.00) for the diagnosis of choledocholithiasis, without lengthening the median reading time (16.2 s for the combination of conventional CT and VNC images vs. 14.7 s for conventional CT alone; P= 0.325). Based on decision curve analysis, adding VNC imaging to conventional unenhanced CT resulted in a higher net benefit among most of decision thresholds. No differences in diagnostic performance were found between the combination of conventional unenhanced CT and VNC imaging (AUC, 0.877; 95% CI: 0.808, 0.947) and MRCP (AUC, 0.913; 95% CI: 0.852, 0.974) (P= 0.458). CONCLUSIONS: VNC images derived from dual-energy unenhanced CT have incremental diagnostic value for the diagnosis of choledocholithiasis. Unenhanced CT in a dual-energy mode may be a useful tool for the diagnosis of choledocholithiasis.

Gadolinium Enhances Dual-energy Computed Tomography Scan of Pulmonary Artery.

OBJECTIVE: To evaluate the feasibility of using gadopentetate dimeglumine (Gd-DTPA) for dual-energy computed tomography pulmonary angiography (CTPA). METHODS: Sixty-six patients were randomly divided into three groups and underwent CTPA. Group A had a turbo flash scan using an iohexol injection, Group B had a turbo flash scan using Gd-DTPA, and Group C had a dual-energy scan using Gd-DTPA. The original images of Group C were linearly blended with a blending factor of 0.5 or reconstructed at 40, 50, 60, 70, 80, 90, 100, and 110 keV, respectively. The groups were compared in terms of pulmonary artery CT value, image quality, and radiation dose. RESULTS: The pulmonary artery CT values were significantly higher in Group C40keV than in Groups B and C, but lower than in Group A. There was no significant difference in the image noise of Groups C40keV, B, and C. Moreover, Group A had the largest beam hardening artifacts of the superior vena cava (SVC), followed by Groups B and C. Group C40keV showed better vascular branching than the other three groups, among which Group B was superior to Group A. The subjective score of the image quality of Groups A, B, and C showed no significant difference, but the score was significantly higher in Group C40keV than in Groups A and B. The radiation dose was significantly lower in Group B than in Groups A and C. CONCLUSION: Gd-CTPA is recommended to patients who are unsuitable for receiving an iodine-based CTPA. Furthermore, a turbo flash scan could surpass a dual-energy scan without consideration for virtual monoenergetic imaging.

Mesoscopic and macroscopic investigation of a dolomitic marble subjected to thermal damage.

Thermal loading is an important factor that could lead to the weakening and deterioration of rock materials. Understanding the thermal properties of rocks and their evolution under different high temperatures is important in the post-fire-hazard evaluation and cultural heritage conservation. Yet it is challenging to understand the evolution of thermally-induced changes in rock properties and to quantitatively study degrees of thermal damage when samples are limited. This study investigates the effects of high temperatures (i.e., 200 °C, 400 °C, 600 °C, 800 °C, and 1000 °C) on a dolomitic marble using combined mesoscopic and macroscopic testing techniques. The test results show that increasing marble temperature led to a deterioration of physical properties (i.e., increasing open porosity and weight loss; but decreasing P-wave velocity) and mechanical properties (i.e., increasing axial strain corresponding with the peak stress; but decreasing uniaxial compressive strength, Young's modulus, and brittleness). There existed a threshold temperature of 600 °C, which marks different thermal damage mechanisms. Below the threshold, the rock deterioration was mainly caused by physical changes such as crack propagation and grain breakage, which can be characterized by mesoscopic parameters (i.e., linear crack density and mineral grain size distribution). On the contrary, when the temperature was higher than the threshold, the deterioration was caused by chemical changes, including mineral decomposition and re-crystallization, which was indicated by the changes in mineral compositions and relative atomic mass calculation. Based on the experimental results (e.g., mineralogical and physico-mechanical changes) and obtained relationships between the parameters in mesoscale and macroscale, a novel scheme for thermal damage evaluation is proposed to estimate thermally-induced changes in macroscopic parameters (e.g., Young's modulus) based on the corresponding mesoscopic parameters (e.g., particle size distribution and linear crack density).

Reconfigurable meta-radiator based on flexible mechanically controlled current distribution in three-dimensional space.

In this paper, we provide an experimental proof-of-concept of this dynamic three-dimensional (3D) current manipulation through a 3D-printed reconfigurable meta-radiator with periodically slotted current elements. By utilizing the working frequency and the mechanical configuration comprehensively, the radiation pattern can be switched among 12 states. Inspired by maximum likelihood method in digital communications, a robustness-analysis method is proposed to evaluate the potential error ratio between ideal cases and practice. Our work provides a previously unidentified model for next-generation information distribution and terahertz-infrared wireless communications.

Enhanced piezocapacitive response in zinc oxide tetrapod-poly(dimethylsiloxane) composite dielectric layer for flexible and ultrasensitive pressure sensor.

We demonstrate polymeric piezocapacitive pressure sensors based on a novel composite dielectric film of poly(dimethylsiloxane) elastomeric silicone and zinc oxide tetrapod. With an appropriate loading of zinc oxide tetrapods, composite piezocapacitive pressure sensors show a 75-fold enhancement of pressure sensitivity over pristine devices, achieving a marked value as high as 2.55 kPa-1. The limit of detection was estimated to be about 10 mg, corresponding to a subtle stimulus of only 1.0 Pa. Besides, versatile functionalities such as detection of finger bending/straightening, calligraphy writing, and air flow blowing have been investigated. It is expected that the proposed piezocapacitive pressure sensors incorporating stress-sensitive additives of zinc oxide nanostructures may provide a promising means for potential applications in ultrasensitive wearable, healthcare systems and human-machine interfaces.

Characteristics and weathering mechanisms of the traditional Chinese blue brick from the ancient city of Ping Yao.

The traditional blue brick was the dominant clay brick used in Chinese architecture before the mid-nineteenth century. The ancient city of Ping Yao, a United Nations Educational, Scientific and Cultural Organization (UNESCO) heritage site, is an outstanding example of blue brick architecture. The Ping Yao bricks within the damp areas (up to 4 m at highest) of the ancient city's walls and private houses are subjected to various weathering, including contour scaling, flaking, powdering and salt crystallization. This study aims to characterize the properties, analyse weathering mechanisms, determine the main weathering factors and discuss the anti-weathering strategies of blue bricks. To do so, samples of brick and salt efflorescence were collected from the historical buildings of Ping Yao and were studied with regard to their mineralogical and physico-mechanical (e.g. density, porosity, pore size distribution, water absorption and uniaxial compressive strength) properties. The resistance to salt crystallization and frost, and the maximum firing temperatures of the brick samples were determined in the laboratory. Weathering mechanisms and anti-weathering strategies were discussed. Salt crystallization and freeze-thaw cycles were found to be two important factors that lead to brick weathering. An anti-weathering strategy of 'damp blocking, desalination and brick replacing' was discussed based on the laboratory experiments, suggestions in literature and site conditions.

Liver metastasis from adenoid cystic carcinoma of the submandibular gland: a case report.

BACKGROUND: Adenoid cystic carcinoma (ACC) is a rare malignancy of epithelial origin. It involves a variety of histologic types and often has distant metastasis. ACC metastasis to the liver is rare and usually involves spread to other organs. CASE PRESENTATION: We report a case of liver metastasis from a submandibular gland adenoid cystic carcinoma 11 years after resection of tumor. The patient was admitted to our hospital due to a liver-occupying lesion found by abdominal B-ultrasound, CT and MRI. A metastasis was found only in the liver, and after discussion the patient was treated with surgery. This tumor was histologically consistent with the diagnostic criteria of ACC. The patient was followed up 24 months after surgery, and showed no recurrence in the liver parenchyma at the site of operation or other organs. CONCLUSIONS: ACC is a very rare tumor and its pathogenesis is not completely clear. There are few articles about the imaging findings of ACC in the liver, and so it was difficult for us to make a correct diagnosis in clinical practice. The diagnosis of ACC mainly relies on pathologic examination, so we summarize the correlation between imaging and pathology.

Imaging findings of inflammatory pseudotumor-like follicular dendritic cell tumors of the liver: Two case reports and literature review.

BACKGROUND: Inflammatory pseudotumor-like follicular dendritic cell (IPT-like FDC) tumors of the liver is an uncommon tumor with extremely low incidence. To date, the radiologic findings of this tumor in multiphase computed tomography (CT) and magnetic resonance imaging (MRI) imaging have not been described. CASE SUMMARY: Patient 1 is a 31-year-old Chinese female, whose complaining incidentally coincided with the finding of multiple liver masses. In the local hospital, an abdominal enhanced CT found two hypo-dense solid lesions, with heterogeneous sustained hypoenhancement, in the upper segment of the liver's right posterior lobe. In our hospital, enhanced magnetic resonance imaging (MRI) with hepatocyte-specific contrast agents showed a similar enhanced pattern of lesions with patchy hyperintensity in the hepatobiliary phase (HBP). The patient underwent surgery and recovered well. The final pathology confirmed an IPT-like FDC tumor. No recurrence was found on the regular re-examination. Patient 2 is a 48-year-old Chinese male admitted to our hospital for a huge unexpected hepatic lesion. A dynamic enhanced abdominal CT revealed a huge heterogeneous enhanced solid tumor in the right lobe of the liver with a size of 100 mm × 80 mm, which showed a heterogeneous sustained hypoenhancement. In addition, enlarged lymph nodes were found in the hilum of the liver. This patient underwent a hepatic lobectomy and lymph node dissection. The final pathology confirmed an IPT-like FDC tumor. No recurrence was found upon regular re-examination. CONCLUSION: When a hepatic tumor shows heterogeneous sustained hypoenhancement with a patchy enhancement during HBP, an IPT-like FDC tumor should be considered in the differential diagnosis.

Three-dimensional metacrystals with a broadband isotropic diamagnetic response and an all-angle negative index of refraction.

Metamaterials (MMs) and photonic crystals (PhCs) exhibiting artificially engineered physical properties have been widely studied in the past decade. However, abnormal properties could only be proposed under a limited range of polarization and directions in most of the previous studies. It is still a challenge to realize an isotropic artificial material with multiple exotic electromagnetic properties. Here we report a three-dimensional metacrystal supporting full polarization and omni-directional incidence. The center-symmetric unit cell consists of non-resonant closed metallic loops on each surface of the dielectric cube. With the cross-scale dispersion engineering, the metacrystal can exhibit an isotropic diamagnetic response and an all-angle negative index of refraction simultaneously at the opposite sides of the MM-PhC transition region. An additional numerical analysis shows the good performance in terahertz and mid-infrared frequencies, which indicates its potential applications on multi-functional optical components with wide polarization-and-direction allowance.

Thermally induced deterioration behaviour of two dolomitic marbles under heating-cooling cycles.

Thermally induced deterioration behaviour can cause severe weathering in marbles. Most previous studies focus on the deterioration behaviour of calcitic marbles. Relevant studies of dolomitic marbles are generally carried out under a 'high temperature and low cycling times' condition. Little attention is focused on the deterioration behaviour in dolomitic marbles when they are subjected to a large quantity of heating-cooling cycles under a 'low temperature and high cycling times' condition. This paper presents experimental investigations on the thermally induced deterioration behaviour of two Beijing dolomitic marbles (Qingbaishi Marble (QM) and Hanbaiyu Marble (HM)) under heating-cooling cycles up to 1000 cycling times. The applied temperature range is from -20°C to 60°C which is to simulate the seasonal temperature variations in Beijing city, China. Related properties such as weight loss, three-dimensional microtopography, elastic wave velocity and uniaxial compressive strength were measured at certain cycles. The results indicate that thermally induced deterioration behaviour will result in a continuous weight loss in dolomitic marble samples. Mechanical properties of those two marbles are strongly affected by heating and cooling treatments, which were reflected by the reductions of dynamic Young's modulus and uniaxial compressive strength with an increase of thermal cycles. Compared with QM, HM displays a higher level of thermally induced deterioration which should be due to the abundance of quartz mineral.

Post-traumatic High-flow Priapism: Multidetector Computed Tomography Demonstration.

High-flow priapism due to pseudoaneurysm is a relatively rare urologic condition. Clear anatomic delineation of the number and origin of feeding vessels facilitates pre-embolization planning. Computed tomographic angiography can afford a three-dimensional display of the feeding vessels. We present a 26-year-old man with post-traumatic high-flow priapism, which is the first case studied with computed tomographic angiography.

Aroma-active compounds in jinhua ham produced with different fermentation periods.

The aroma-active compounds in Jinhua ham processed and stored for 9, 12, 15 and 18 months were extracted by dynamic headspace sampling (DHS) and solvent-assisted flavor evaporation (SAFE) and analyzed by gas chromatography-olfactometry-mass spectrometry (GC-O-MS). In GC-O-MS, volatile compounds were identified based on their mass spectrum, linear retention index (LRI), odor properties, or reference compound comparisons. The results showed that a total number of 81 aroma-active compounds were identified by GC-O-MS. Among them, acids (such as acetic acid, butanoic acid and 3-methylbutanoic acid), saturated aldehydes (such as hexanal, heptanal, octanal and 3-methylbutanal), benzene derivatives (such as benzeneacetic acid), ester and lactone (such as γ-nonalactone and γ-decalactone) were identified as critical compounds in Jinhua ham aroma. The results also indicated that the type and content of the odorants increased significantly with the duration of the fermentation period.

Analysis of Geographic and Pairwise Distances among Chinese Cashmere Goat Populations.

This study investigated the geographic and pairwise distances of nine Chinese local Cashmere goat populations through the analysis of 20 microsatellite DNA markers. Fluorescence PCR was used to identify the markers, which were selected based on their significance as identified by the Food and Agriculture Organization of the United Nations (FAO) and the International Society for Animal Genetics (ISAG). In total, 206 alleles were detected; the average allele number was 10.30; the polymorphism information content of loci ranged from 0.5213 to 0.7582; the number of effective alleles ranged from 4.0484 to 4.6178; the observed heterozygosity was from 0.5023 to 0.5602 for the practical sample; the expected heterozygosity ranged from 0.5783 to 0.6464; and Allelic richness ranged from 4.7551 to 8.0693. These results indicated that Chinese Cashmere goat populations exhibited rich genetic diversity. Further, the Wright's F-statistics of subpopulation within total (FST) was 0.1184; the genetic differentiation coefficient (GST) was 0.0940; and the average gene flow (Nm) was 2.0415. All pairwise FST values among the populations were highly significant (p<0.01 or p<0.001), suggesting that the populations studied should all be considered to be separate breeds. Finally, the clustering analysis divided the Chinese Cashmere goat populations into at least four clusters, with the Hexi and Yashan goat populations alone in one cluster. These results have provided useful, practical, and important information for the future of Chinese Cashmere goat breeding.

[Discussion of indoor quality control method of MPAIA antibody test of Schistosoma japonicum].

OBJECTIVE: To explore the scientific and effective indoor quality control method to ensure the results of Magnetic Particle Antibody Immunoassay (MPAIA) antibody test of Schistosoma japonicum reliable. METHODS: The MPAIA antibody test indoor quality control work was performed with the combination of the crubbs method, Z-scores figure and Westgard multi-rules quality control method. RESULTS: The crubbs test entered the quality control condition state from the third times, after 20 times, the test switched to Z-scores conventional quality control, and the Westgard multi-rules quality control method could help analyze the type of errors. From the third to fortieth test, 186 samples were completed and the tests of 9 samples among 2 batches needed to be re-done because of the failure of quality control. The test results of other 177 samples were acceptable. CONCLUSION: The combination of the crubbs method, Z-scores figure and Westgard multi-rules quality control method can effectively accomplish the indoor quality control of MPAIA antibody test of Schistosoma japonicum.

Transparent luminescent bulk nanocomposites of polysiloxane embedded with CdS nanocrystallines by a direct dispersion process.

Transparent luminescent bulk nanocomposites of polysiloxane (PSO) embedded with semiconductor nanocrystals (NCs) have been fabricated by the direct dispersion of CdS NCs in alkyl-(poly)siloxane (APS) followed by co-polymerization. The non-polar characteristics of the APS precursor are compatible with the CdS NC surface (oleylamine), which allows the direct dispersion of the CdS NCs without the need of any surfactant exchange. Chemical crosslinking of the NC-APS dispersion via hydrosilylation between Si-H and the vinyl group in APS immobilizes the CdS NCs in the polysiloxane network. Net-shaped three-dimensional bulk transparent polysiloxane/CdS NC composites were obtained by liquid casting of the NC-precursor dispersion and chemical crosslinking. The PSO/CdS NC composites show visible luminescence under ultraviolet excitation and the luminescent color is tunable from blue to red by controlling the NC concentration in the composite. Photoluminescence spectral analyses reveal the origin of the luminescence as being from the defect emission of the CdS NCs (550-900 nm) and an emission from the PSO matrix (380-550 nm). The luminescent spectra covered a wide range from the ultraviolet to the near-infrared region. The luminescence of the PSO/CdS NC nanocomposites was stable without any apparent degradation after exposure to air for a long time. This simple direct dispersion process is feasible for the fabrication of luminescent nanocomposites with useful optical properties for potential applications in optics and photoelectron devices.

Nickel and zinc complexes with a monodentate heterocycle and tridentate Schiff base ligands: self-assembly to one- and two-dimensional supramolecular networks via hydrogen bonding.

In the complex (morpholine)[2-hydroxy-N'-(5-nitro-2-oxidobenzylidene)benzohydrazidato]nickel(II), [Ni(C(14)H(9)N(3)O(5))(C(4)H(9)NO)], (I), the Ni(II) center is in a square-planar N(2)O(2) coordination geometry. The complex bis[mu-2-hydroxy-N'-(2-oxidobenzylidene)benzohydrazidato]bis[(morpholine)zinc(II)], [Zn(2)(C(14)H(10)N(2)O(3))(2)(C(4)H(9)NO)(2)], (II), consists of a neutral centrosymmetric dimer with a coplanar Zn(2)(mu(2)-O)(2) core. The two Zn(II) centers are bridged by phenolate O atoms. Each Zn(II) center exhibits a distorted square-pyramidal stereochemistry, in which the four in-plane donors come from the O,N,O'-tridentate 2-hydroxy-N'-(2-oxidobenzylidene)benzohydrazidate(2-) ligand and a symmetry-related phenolate O atom, and the axial position is coordinated to the N atom from the morpholine molecule. There are intramolecular phenol-hydrazide O-H...N hydrogen bonds present in both (I) and (II). In (I), square-planar nickel complexes are linked by intermolecular morpholine-morpholine N-H...O hydrogen bonds, leading to a one-dimensional chain, while in (II) an infinite two-dimensional network is formed via intermolecular hydrogen bonds between the coordinated morpholine NH groups and the uncoordinated phenolate O atoms.

[The risk factor for low bone mineral density in patients with inflammatory bowel disease].

OBJECTIVE: To evaluate the prevalence of low bone mineral density in patients with inflammatory bowel disease (IBD)and to identify its risk factors. METHODS: A cross-sectional survey was carried out in IBD patients. Anthropometric measures, biochemical markers of nutrition and bone mineral density measurement were completed for these patients as well as healthy control subjects. RESULTS: Seventy-seven Crohn's disease (CD) and 43 ulcerative colitis (UC) patients were enrolled, and 37 healthy volunteers were recruited as healthy controls (HC). The T value of CD patients, UC patients and HC was -1.72 +/- 1.20, -1.26 +/- 1.12 and -0.62 +/- 0.87 respectively and the T value of CD patients was significantly lower than that of HC (P = 0.000). The prevalence of osteoporosis in CD, UC and HC was 23.3%, 14.0% and 0 respectively. The prevalence of osteoporosis in CD was higher than that in HC (P = 0.003). Logistic regression analysis indicated that low BMI (BMI < or = 18.4 kg/m(2)) was an independent risk factor for osteoporosis both in CD (OR = 11.25, 95%CI 3.198 - 39.580, P = 0.000) and in UC (OR = 14.50, 95%CI 1.058 - 88.200, P = 0.045) patients. Age, disease duration, clinical activity active index (CDAI), oral steroid therapy, immunosuppressant treatment and serum vitamin D concentration were not found to be correlated with osteoporosis in IBD patients. CONCLUSIONS: Low bone mineral density is common in both CD and UC patients and low BMI is an independent risk factor for osteoporosis in IBD patients.