CT-derived extracellular volume and liver volumetry can predict posthepatectomy liver failure in hepatocellular carcinoma.

OBJECTIVES: Posthepatectomy liver failure (PHLF) is a severe complication of liver resection. We aimed to develop and validate a model based on extracellular volume (ECV) and liver volumetry derived from computed tomography (CT) for preoperative predicting PHLF in resectable hepatocellular carcinoma (HCC) patients. METHODS: A total of 393 resectable HCC patients from two hospitals were enrolled and underwent multiphasic contrast-enhanced CT before surgery. A total of 281 patients from our hospital were randomly divided into a training cohort (n = 181) and an internal validation cohort (n = 100), and 112 patients from another hospital formed the external validation cohort. CT-derived ECV was measured on nonenhanced and equilibrium phase images, and liver volumetry was measured on portal phase images. The model is composed of independent predictors of PHLF. The under the receiver operator characteristic curve (AUC) and calibration curve were used to reflect the predictive performance and calibration of the model. Comparison of AUCs used the DeLong test. RESULTS: CT-derived ECV, measured future liver remnant (mFLR) ratio, and serum albumin were independent predictors for PHLF in resectable HCC patients. The AUC of the model was significantly higher than that of the ALBI score in the training cohort, internal validation cohort, and external validation cohort (all p < 0.001). The calibration curve of the model showed good consistency in the training cohort and the internal and external validation cohorts. CONCLUSIONS: The novel model contributes to the preoperative prediction of PHLF in resectable HCC patients. CRITICAL RELEVANCE STATEMENT: The novel model combined CT-derived extracellular volume, measured future liver remnant ratio, and serum albumin outperforms the albumin-bilirubin score for predicting posthepatectomy liver failure in patients with resectable hepatocellular carcinoma. KEY POINTS: • CT-derived ECV correlated well with the fibrosis stage of the background liver. • CT-derived ECV and mFLR ratio were independent predictors for PHLF in HCC. • The AUC of the model was higher than the CT-derived ECV and mFLR ratio. • The model showed a superior predictive performance than that of the ALBI score.

The utility of diffusion-weighted imaging for differentiation of phyllodes tumor from fibroadenoma and breast cancer.

Objective: To evaluate the utility of apparent diffusion coefficient (ADC) values for differentiating breast tumors. Methods: The medical records of 17 patients with phyllodes tumor [PT; circular regions of interest (ROI-cs) n = 171], 74 patients with fibroadenomas (FAs; ROI-cs, n = 94), and 57 patients with breast cancers (BCs; ROI-cs, n = 104) confirmed by surgical pathology were retrospectively reviewed. Results: There were significant differences between PTs, FAs, and BCs in ADCmean, ADCmax, and ADCmin values. The cutoff ADCmean for differentiating PTs from FAs was 1.435 × 10-3 mm2/s, PTs from BCs was 1.100 × 10-3 mm2/s, and FAs from BCs was 0.925 × 10-3 mm2/s. There were significant differences between benign PTs, borderline PTs, and malignant PTs in ADCmean, ADCmax, and ADCmin values. The cutoff ADCmean for differentiating benign PTs from borderline PTs was 1.215 × 10-3 mm2/s, and borderline PTs from malignant PTs was 1.665 × 10-3 mm2/s. Conclusion: DWI provides quantitative information that can help distinguish breast tumors.

Native Oxidation and Complex Magnetic Anisotropy-Dominated Soft Magnetic CoCrFeNi-Based High-Entropy Alloy Thin Films.

Soft magnetic high-entropy alloy thin films (HEATFs) exhibit remarkable freedom of material-structure design and physical-property tailoring, as well as, high cut-off frequencies and outstanding electrical resistivities, making them potential candidates for high-frequency magnetic devices. In this study, a CoCrFeNi film with excellent soft magnetic properties is developed by forming a novel core-shell structure via native oxidation, with ferromagnetic elements Fe, Co, and Ni as the core and the Cr oxide as the shell layer. The core-shell structure enables a high saturation magnetization, enhances the electrical resistivity, and thus reduces the eddy-current loss. For further optimizing the soft magnetic properties, O is deliberately introduced into the HEATFs, and the O-incorporated HEATFs exhibit an electrical resistivity of 237 µΩ·cm, a saturation magnetization of 535 emu cm-3 , and a coercivity of 23 A m-1 . The factors that determine the ferromagnetism and coercivity of the CoCrFeNi-based HEATFs are examined in detail by evaluating the microstructures, magnetic domains, chemical valency, and 3D microscopic compositional distributions of the prepared films. These results are anticipated to provide insights into the magnetic behaviors of soft magnetic HEATFs, as well as aid in the construction of a promising material-design strategy for these unique materials.

Modulation Recognition of Communication Signals Based on Multimodal Feature Fusion.

Modulation recognition is the indispensable part of signal interception analysis, which has always been the research hotspot in the field of radio communication. With the increasing complexity of the electromagnetic spectrum environment, interference in signal propagation becomes more and more serious. This paper proposes a modulation recognition scheme based on multimodal feature fusion, which attempts to improve the performance of modulation recognition under different channels. Firstly, different time- and frequency-domain features are extracted as the network input in the signal preprocessing stage. The residual shrinkage building unit with channel-wise thresholds (RSBU-CW) was used to construct deep convolutional neural networks to extract spatial features, which interact with time features extracted by LSTM in pairs to increase the diversity of the features. Finally, the PNN model was adapted to make the features extracted from the network cross-fused to enhance the complementarity between features. The simulation results indicated that the proposed scheme has better recognition performance than the existing feature fusion schemes, and it can also achieve good recognition performance in multipath fading channels. The test results of the public dataset, RadioML2018.01A, showed that recognition accuracy exceeds 95% when the signal-to-noise ratio (SNR) reaches 8dB.

Apparent diffusion coefficient histogram analysis for differentiating solid ovarian tumors.

Objective: To evaluate the utility of apparent diffusion coefficient (ADC) histogram analysis to differentiate between three types of solid ovarian tumors: granulosa cell tumors (GCTs) of the ovary, ovarian fibromas, and high-grade serous ovarian carcinomas (HGSOCs). Methods: The medical records of 11 patients with GCTs of the ovary (regions of interest [ROI-cs], 137), 61 patients with ovarian fibromas (ROI-cs, 161), and 14 patients with HGSOCs (ROI-cs, 113) confirmed at surgery and histology who underwent diffusion-weighted imaging were retrospectively reviewed. Histogram parameters of ADC maps (ADCmean, ADCmax, ADCmin) were estimated and compared using the Kruskal-WallisH test and Mann-Whitney U test. The area under the curve of receiver operating characteristic curves was used to assess the diagnostic performance of ADC parameters for solid ovarian tumors. Results: There were significant differences in ADCmean, ADCmax and ADCmin values between GCTs of the ovary, ovarian fibromas, and HGSOCs. The cutoff ADCmean value for differentiating a GCT of the ovary from an ovarian fibroma was 0.95×10-3 mm2/s, for differentiating a GCT of the ovary from an HGSOC was 0.69×10-3 mm2/s, and for differentiating an ovarian fibroma from an HGSOC was 1.24×10-3 mm2/s. Conclusion: ADCmean derived from ADC histogram analysis provided quantitative information that allowed accurate differentiation of GCTs of the ovary, ovarian fibromas, and HGSOCs before surgery.

Myocardial extracellular volume derived from contrast-enhanced chest computed tomography for longitudinal evaluation of cardiotoxicity in patients with breast cancer treated with anthracyclines.

OBJECTIVES: To assess the value of myocardial extracellular volume (ECV) derived from contrast-enhanced chest computed tomography (CT) for longitudinal evaluation of cardiotoxicity in patients with breast cancer (BC) treated with anthracycline (AC). MATERIALS AND METHODS: A total of 1151 patients with BC treated with anthracyclines, who underwent at least baseline, and first follow-up contrast-enhanced chest CT were evaluated. ECV and left ventricular ejection fraction (LVEF) were measured before (ECV0, LVEF0), during ((ECV1, LVEF1) and (ECV2, LVEF2)), and after (ECV3, LVEF3) AC treatment. ECV values were evaluated at the middle of left ventricular septum on venous phase images. Cancer therapy-related cardiac dysfunction (CTRCD) was recorded. RESULTS: Mean baseline LVEF values were 65.85% ± 2.72% and 102 patients developed CTRCD. The mean ECV0 was 26.76% ± 3.03% (N0 = 1151). ECV1, ECV2, and ECV3 (median interval: 61 (IQR, 46-75), 180 (IQR, 170-190), 350 (IQR, 341-360) days from baseline) were 31.32% ± 3.10%, 29.60% ± 3.24%, and 32.05% ± 3.58% (N1 = 1151, N2 = 841, N3 = 511). ECV1, ECV2, and ECV3 were significantly higher than ECV0 (p < 0.001). ECV0 and ECV1 showed no difference between CTRCD (+) and CTRCD (-) group (p1 = 0.150; p2 = 0.216). However, ECV2 and ECV3 showed significant differences between the two groups (p3 < 0.001; p4 < 0.001). CONCLUSION: CT-derived ECV is a potential biomarker for dynamic monitoring AC cardiotoxicity in patients with BC.

Longitudinal pericardial adipose tissue changes in patients with breast cancer receiving anthracycline-based chemotherapy: a retrospective cohort study.

Background: Pericardial adipose tissue (PAT) has been associated with adverse cardiac events. In this study, we evaluated changes of PAT in patients with breast cancer during and after anthracycline-based chemotherapy and explored the clinical variables associated with increases in PAT volume at the completion of chemotherapy. Methods: A total of 278 breast cancer patients who were receiving anthracycline-based chemotherapy were retrospectively enrolled. Their PAT volumes were measured using non-contrast chest computed tomography (CT) images from a dedicated workstation. We compared these volumes to their measurements at baseline, during different chemotherapy cycles, at and after chemotherapy completion. We identified the clinical variables associated with increases in PAT volume at chemotherapy completion using logistic regression analyses. Results: At the completion of chemotherapy, PAT volumes were shown to have increased compared to baseline measurements (87.67±45.09 vs. 104.25±47.74 cm3; P=0.00). After 4, 6, and 8 chemotherapy cycles, PAT volumes increased from the baseline measurement by 9.48% [95% confidence interval (CI): -2.30% to 21.27%], 14.75% (95% CI: 4.68% to 24.82%), and 20.02% (95% CI: 11.38% to 28.66%), respectively. Compared to volumes measured at chemotherapy completion (104.25±47.74 cm3), PAT volumes at 6 and 12 months after chemotherapy completion were 105.23±49.27 and 107.56±46.34 cm3, respectively. The differences between chemotherapy completion and follow-up PAT volumes were not statistically significant. A variable associated with an increase in PAT from baseline to chemotherapy completion was the number of chemotherapy cycles (8 vs. 4) [odds ratio (OR) =3.850; 95% CI: 1.751 to 8.488]. Conclusions: Patients with breast cancer who undergo anthracycline-based chemotherapy can experience unfavorable PAT volume increases, which are maintained after the completion of treatment. Patients at risk of increases in PAT volume at chemotherapy completion can be identified based on clinical risk factors and targeted for interventions.

The utility of diffusion-weighted imaging and ADC values in the characterization of mumps orchitis and seminoma.

BACKGROUND: Diffusion-weighted imaging (DWI) can quantitatively reflect the diffusion characteristics of tissues, providing a theoretical basis for qualitative diagnosis and quantitative analysis of a disease. PURPOSE: To characterize testicular lesions that present as a hypointense signal on magnetic resonance imaging (MRI) T2-weighted images using DWI. MATERIAL AND METHODS: Study participants were divided into three groups. Group A were healthy controls (n = 35), group B included patients with mumps orchitis (n = 20), and group C included patients with seminoma (n = 15). DWI sequences used b-values of 0, 1000, and 2000 s/mm2. Apparent diffusion coefficient (ADC) values between 1000 and 2000 s/mm2 were calculated by MRI postprocessing software. The Kruskal-Wallis test and receiver operating characteristic analysis were performed to evaluate how well ADC values distinguished between mumps orchitis and seminoma. RESULTS: Normal testicular tissue showed a hyperintense signal on DWI and hypointensity on the ADC map: mean ADC value was 0.77 (0.69-0.85) ± 0.08 ×10-3 mm2/s. Mumps orchitis and seminoma showed slight hyperintensity on DWI: mean ADC values were 0.85 (0.71-0.99) ± 0.15 ×10-3 mm2/s and 0.43 (0.39-0.47) ± 0.04 × 10-3 mm2/s, respectively. There were statistically significant differences in mean ADC values between normal testicular tissue and seminoma and between mumps orchitis and seminoma. The cutoff ADC value for differentiating seminoma from mumps orchitis was 0.54 × 10-3 mm2/s. The sensitivity, specificity, and Youden Index for diagnosing seminoma were 99%, 31%, and 30%, respectively. CONCLUSION: High b-value DWI has potential utility for differentiating mumps orchitis from seminoma in the clinical setting.

Multiparametric dual-energy CT to differentiate stage T1 nasopharyngeal carcinoma from benign hyperplasia.

BACKGROUND: Stage T1 nasopharyngeal carcinoma (NPCT1) and benign hyperplasia (BH) are 2 common causes of nasopharyngeal mucosa/submucosa thickening without specific clinical symptoms. The treatment management of these 2 entities is significantly different. Reliable differentiation between the 2 entities is critical for the treatment decision and prognosis of patients. Therefore, our study aims to explore the optimal energy level of noise-optimized virtual monoenergetic images [VMI (+)] derived from dual-energy computed tomography (DECT) to display NPCT1 and BH and to explore the clinical value of DECT for differentiating these 2 diseases. METHODS: A total of 91 patients (44 NPCT1, 47 BH) were enrolled. The demarcation of the lesion margins and overall image quality, noise, contrast-to-noise ratio (CNR), and signal-to-noise ratio (SNR) were evaluated for 40-80 kiloelectron volts (keV) VMIs (+) and polyenergetic images in the contrast-enhanced phase. Image features were assessed in the contrast-enhanced images with optimal visualization of NPCT1 and BH. The demarcation of NPCT1 and BH in iodine-water maps was also assessed. The contrast-enhanced images were used to calculate the slope of the spectral Hounsfield unit curve (λHU) and normalized iodine concentration (NIC). The nonenhanced phase images were used to calculate the normalized effective atomic number (NZeff). The attenuation values on 40-80 keV VMIs (+) in the contrast-enhanced phase were recorded. The diagnostic performance was assessed using receiver operating characteristic (ROC) curve analysis. RESULTS: The 40 keV VMI (+) in the enhanced phase yielded higher demarcation of the lesion margins scores, overall image quality scores, noise, SNR, and CNR values than 50-80 keV VMIs (+) and polyenergetic images. NPCT1 yielded higher attenuation values on VMI (+) at 40 keV (A40), NIC, λHU, and NZeff values than BH. The multivariate logistic regression model combining image features (tumor symmetry) with quantitative parameters (A40, NIC, λHU, and NZeff) yielded the best performance for differentiating the 2 diseases (AUC: 0.963, sensitivity: 89.4%, specificity: 93.2%). CONCLUSIONS: The combination of DECT-derived image features and quantitative parameters contributed to the differentiation between NPCT1 and BH.

Simultaneous multi-slice readout-segmentation of long variable echo-trains for accelerated diffusion-weighted imaging of nasopharyngeal carcinoma: A feasibility and optimization study.

OBJECTIVES: We aimed to evaluate the feasibility of simultaneous multi-slice readout segmentation of long variable echo-trains (SMS-RESOLVE) for diffusion-weighted imaging (DWI) of nasopharyngeal carcinoma (NPC) and determine the optimal acceleration factor of SMS-RESOLVE DWI compared with conventional RESOLVE DWI. MATERIALS AND METHODS: One hundred and five patients with histologically confirmed NPC were enrolled. DWIs including conventional RESOLVE DWI, SMS-RESOLVE DWI with acceleration factors of 2 and 3 (2 × SMS-RESOLVE and 3 × SMS-RESOLVE) were acquired at b-values of 0 and 800 s/mm2. The subjective image quality, including overall image quality, lesion conspicuity, and lesion distortion scores, and objective image quality, including signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and contrast in these three protocols, were assessed and compared. The apparent diffusion coefficients (ADCs) of the primary tumor and right masseter muscle and normalized ADCs in the three protocols were measured and compared. RESULTS: The 2 × SMS-RESOLVE provided comparable image quality and ADCs with a 48.3% reduction in scan time compared with conventional RESOLVE DWI. The 3 × SMS-RESOLVE showed significantly poorer image quality and the highest ADCs with a 56.9% reduction in scan times compared with conventional RESOLVE DWI. CONCLUSION: The SMS-RESOLVE DWI with an acceleration factor of 2 yielded the best compromise between image quality and scan time reduction and could be an alternative to conventional RESOLVE DWI for nasopharyngeal carcinoma.

Apparent diffusion coefficient values of cryptorchid testes and malignant transformation of cryptorchidism (MTC) (seminoma) in postpubertal patients.

OBJECTIVES: Diffusion-weighted imaging signal contrast can be quantified by apparent diffusion coefficient (ADC) maps, which reflect the diffusion properties of the examined tissue and are helpful for identifying pathology. To determine ADC values of cryptorchid testes in post-pubertal patients and assess performance for characterizing cryptorchid testes. METHODS: The medical records from 35 patients with unilateral scrotal vacuity were retrospectively reviewed. Data were analyzed in three groups: Group A, normal testes (i.e. the contralateral testes of the patients with cryptorchidism or MTC); Group B, cryptorchid testes; and Group C, malignant transformation of cryptorchidism (MTC) (seminoma). DWI used b-values of 0 and 800 s/mm2. Mean ADC values were compared using the independent samples t-test. The ability of ADC values was assessed using receiver operating characteristic curve analysis. The sensitivity, specificity, and accuracy were calculated. RESULTS: Mean ADC values for normal testes, cryptorchid testes, and MTC were 1.18 ± 0.18×10-3 mm2/s, 1.82 ± 0.40×10-3 mm2/s, and 0.80 ± 0.06×10-3 mm2/s, respectively. There were statistically significant differences in mean ADC values between normal testes and cryptorchid testes or MTC (p < 0.001). The cut-off ADC value for differentiating normal testes from cryptorchid testes was 1.47 × 10-3 mm2/s. The sensitivity, specificity, and accuracy were 88%, 91%, and 90%, respectively. The cut-off ADC value for differentiating normal testes from MTC was 1.22 × 10-3 mm2/s. The sensitivity, specificity, and accuracy were 100%, 31%, and 43%, respectively. CONCLUSION: ADC values of cryptorchid testes may be used to inform clinical decision-making and also monitor testicular function in patients who retain undescended testicles or post-operatively. ADVANCES IN KNOWLEDGE: Mean ADC values of cryptorchidism and MTC (seminoma) were used to reflect their pathological features.

MRI findings of an atypical testicular epidermoid cyst: A case report.

INTRODUCTION: Typical testicular epidermoid cysts (TECs) manifestate as a target sign or onion skin sign on ultrasonography and magnetic resonance (MR) imaging. Clinicians are increasingly aware of the imaging characteristics of typical TECs, which allow accurate diagnosis and successful treatment while preserving the testicle, but atypical TECs are likely to be misdiagnosed as a malignant intratesticular neoplasm, leading to complete testicular resection. PATIENT CONCERNS: A 26 year-old male patient complained of a painless enlargement of the left testicle that had been present for 1 month. The patient had no recent medical history of scrotal trauma or systemic infection. DIAGNOSIS: A round 48 mm × 45 mm × 43 mm mass was seen inside the left testicle. T2-weighted images of the lesion showed a thin hypointense capsule. T1-weighted images of the lesion showed a hyperintense nodule on the cyst wall, which appeared hypointense on T2-weighted and SPAIR images. After Gd-DTPA injection, the lesion was not enhanced; however, the nodule was enhanced on THRIVE images. These manifestations were consistent with a benign intratesticular lesion, and MR imaging diagnosed atypical TEC, which was confirmed by pathology after surgery. INTERVENTIONS: The patient was treated with organ-sparing surgery with testicular enucleation. OUTCOMES: The patient was re-examined with ultrasonography 3 months after surgery. The left residual testicular tissue appeared normal, and reproductive function was preserved. CONCLUSION: Urologists must be aware of the clinical and MR imaging characteristics of atypical TECs and the utility of preoperative MR imaging for the diagnosis of testicular lesions to ensure that organ-sparing surgery is performed rather than unnecessary orchiectomy.

Differentiation of testicular seminoma and nonseminomatous germ cell tumor on magnetic resonance imaging.

Magnetic resonance imaging (MRI) has excellent soft tissue resolution, as well as multidirectional and multisequence scanning technology, making it an important supplementary method in the diagnosis of testicular tumor.To explore the utility of preoperative MRI for the differential diagnosis of testicular seminoma and nonseminomatous germ cell tumors (NSGCTs).The medical records from 39 patients with testicular tumors that were examined preoperatively with MRI and treated with urologic surgery at our institution between January 2015 and March 2019 were retrospectively reviewed. Testicular tumors were confirmed by pathology and classified as seminoma (n = 20) or NSGCT (n = 19). Two radiologists analyzed the testicular tumors on preoperative MRI for morphology: multiple nodules or a single mass; presence/absence of a capsule; signal compared to the normal contralateral testicle (isointense, hypointense, hyperintense, or mixed); enhancement; septa; and hemorrhagic or cystic degeneration. Characteristics of seminomas and NSGCT were compared using the Chi-square or Fischer exact test.MRI showed that the majority (95%; 19/20) of seminomas were nodular. There were significant differences in the presence/absence of a capsule (P = .001), T1-weighted imaging (T1WI) signal intensity (P = .047), T2-weighted imaging (T2WI) signal intensity (P < .001), septa (P < .001), and hemorrhagic or cystic degeneration (P < .001) between seminomas and NSGCT.Seminomas were more likely to have no capsule, isointensity on T1WI, hypointensity on T2WI, and had narrow obviously enhanced fibrovascular septa without hemorrhagic or cystic degeneration; NSGCT was more likely to have a capsule, a mainly mixed signal on T1WI and T2WI, most of them had no fibrovascular septa, and hemorrhagic or cystic degeneration was common in malignant NSGCT.This study suggests that preoperative MRI can distinguish seminoma from NSGCT. We propose that preoperative MRI of the scrotum is an effective technique that should be widely adopted for the management of scrotal disease.

Photocatalytic degradation of dyes over a xylan/PVA/TiO2 composite under visible light irradiation.

In this study, a xylan/PVA/TiO2 composite was prepared and used for the photocatalytic degradation of dyes in solution. Fourier-transform infrared, X-ray diffraction, and X-ray photoelectron spectroscopic analyses confirmed that the xylan/PVA/TiO2 composite was successfully prepared. Furthermore, the composite was evaluated as a photocatalyst for the photodegradation of ethyl violet and Astrazon Brilliant Red 4G dyes under visible light irradiation. The effects of various experimental parameters on the decolorization rate were investigated. Dye decolorization rates of more than 94% were achieved. The major active radical species for EV and ABR photodegradation was found to be positive holes (h+).

Imaging in testicular epidermoid cysts.

OBJECTIVE: To evaluate the utility of findings on ultrasound and magnetic resonance imaging (MRI) for the preoperative diagnosis of testicular epidermoid cysts (TEC). METHODS: The medical records of five patients treated for TEC at our institution between July 2010 and May 2017 were retrospectively reviewed. RESULTS: Imaging revealed a target or onion skin appearance on ultrasonography and MRI. Pathological examinations showed "bread slag-like" materials within the TEC. Lesions failed to demonstrate enhancement after Gd-DTPA injection. CONCLUSION: In the cases of TEC in the current study, accurate diagnosis ensured enucleation of the testicular cyst was performed rather than testicular resection.

Emission Characteristics of Laser-Induced Plasma Using Collinear Long and Short Dual-Pulse Laser-Induced Breakdown Spectroscopy (LIBS).

Collinear long and short dual-pulse laser-induced breakdown spectroscopy (DP-LIBS) was employed to clarify the emission characteristics from laser-induced plasma. The plasma was sustained and became stable by the long pulse-width laser with the pulse width of 60 µs under free running (FR) conditions as an external energy source. Comparing the measurement results of stainless steel in air using single-pulse LIBS (SP-LIBS) and DP-LIBS, the emission intensity was markedly enhanced using DP-LIBS. The temperature of plasma induced by DP-LIBS was maintained at a higher temperature under different gate delay time and short pulse-width laser power conditions compared with those measured using short SP-LIBS. Moreover, the variation rates of plasma temperatures measured using DP-LIBS were also lower. The superior detection ability was verified by the measurement of aluminum sample in water. The spectra were clearly detected using DP-LIBS, whereas it cannot be identified using SP-LIBS of short and long pulse widths. The effects of gate delay time and short pulse-width laser power were also discussed. These results demonstrate the feasibility and enhanced detection ability of the proposed collinear long and short DP-LIBS method.

Free-Standing Single-Molecule Thick Crystals Consisting of Linear Long-Chain Polymers.

Organic two-dimensional (2D) crystals are fundamentally important for development of future devices. Despite that more than a half of man-made products contain polymers, 2D crystals consisting of long linear chains have yet to be explored. Here we report on the fabrication of 2D polyaniline (PANI) crystals via rational electrochemical polymerization followed by liquid-phase exfoliation. The 2D PANI is molecularly thin (∼0.8 nm) and composed of PANI chains with a number-average molecular weight of ∼31 000. The chains are parallel to each other with the benzene rings standing almost vertically to the surface, implying a face-to-face arrangement of the neighboring chains held together by abundant π-π interactions augmented with hydrogen bonds. The 2D PANI can be readily transferred to various solid surfaces and exhibit interesting electrical and optical properties, suggesting that they would be potentially useful in photoelectronic devices and other applications.

[The speed CT measurement of the airway in obstructive sleep apnea-hypopnea syndrome].

OBJECTIVE: To measure the upper airway of obstructive sleep apnea-hypopnea syndrome by speed CT. We can predict the airway obstruction plane with the airway plane data and compliance in OSAHS patients. Through this measurement, we can provide assistance for clinical diagnosis and treatment. METHOD: This study randomly selected 82 patients diagnosed with OSAHS and 45 cases non-snoring healthy people as control group by the PHILIPS 256-slice CT. The zone volume, sagittal diameter, coronary diameter and cross-sectional area of the narrowest plane in nasopharyngeal area, velopharyngeal area, glossopharyngeal area, hypopharynx area in two groups of quiet respiration and Müller's status were measured. RESULT: In the OSAHS group underwent quiet breathing and Müller movement during CT scanning, the two states about nasopharyngeal coronary diameter, the hypopharynx sagittal diameter and cross-sectional area showed no significant difference, while other groups showed differences between the parameters (P<0.05). There was significant difference (P<0.01) in the velopharyngeal volume, tongue sagittal diameter and volume. Under Müller movement in the OSAHS group and the control group, the hypopharynx volume showed no significant difference. The nasopharyngeal coronary diameter and volume, velopharyngeal cross-sectional area and tongue sagittal diameter were different (P<0.05). The remaining set of parameters showed significant differences (P<0.01). Compared the airway compliance (Müller phase) of the OSAHS group and the control group,the parameters of each group were different (P<0.05), of which the nasopharyngeal sagittal diameter, velopharyngeal volume showed significant difference (P<0.01). Meanwhile, in the same plane, coronary diameter was greater than sagittal diameter (P<0.05) in both the OSAHS group and the control group. The pharyngeal volume measurement was basically consistent to the fiber endoscopy. CONCLUSION: The obstruction plate of OSAHS patients is mostly in the velopharyngeal area and glossopharyngeal area measured with a high speed CT. The volume measurement of upper airway with speed CT can predict airway obstruction plate in patients with OSAHS.