Silicon nanowire FET biosensor and its application in acute myocardial infarction.

Over the last two decades, silicon nanowire field-effect transistors (SiNW-FETs) with prominent merits of high surface-to-volume ratio, excellent biocompatibility and mature fabrication with standard silicon technology, have been widely studied as ultrahigh sensitive biosensors for the detection of target biomolecules, such as proteins, nucleic acids, cells and viruses so on. Herein we present a comprehensive review of the fundamental aspects of SiNW-FET biosensors, involving the working principle and the device fabrication, surface functionalization, and system integration with fluid exchange and electrical detection. Futhermore, we emphatically discuss the electrical detection of cardiac-specific biomarkers related to acute myocardial infarction disease. SiNW-FET biosensors are being increasingly exploited as promising diagnostic devices, which provide high sensitivity, high integration density, high speed sampling, strong specificity, and real-time and label-free detection for simple and cheap clinical testing.

Crossed-beam and theoretical studies of multichannel nonadiabatic reactions: branching fractions and role of intersystem crossing for O(3P) + 1,3-butadiene.

Atomic oxygen reactions can contribute significantly to the oxidation of unsaturated aliphatic and aromatic hydrocarbons. The reaction mechanism is started by electrophilic O atom addition to the unsaturated bond(s) to form "chemically activated" triplet oxy-intermediate(s), which can evolve adiabatically on the triplet potential energy surface (PES) and nonadiabatically via intersystem crossing on the singlet PES, forming intermediates that undergo unimolecular decomposition to a variety of bimolecular product channels. Here, we apply a combined crossed molecular beam (CMB)-theoretical approach to the study of the O(3P) + 1,3-butadiene reaction. Although the kinetics of this reaction have been extensively investigated, little is known about the primary products and their branching fractions (BFs). In the present work, a total of eight product channels were observed and characterized in a CMB experiment at a collision energy of 32.6 kJ mol-1. Synergic ab initio transition-state theory-based master equation simulations coupled with nonadiabatic transition-state theory on coupled triplet/singlet PESs were employed to compute the product BFs and assist the interpretation of the CMB experimental results. The good agreement found between the theoretical predictions and CMB experiments supported the use of the adopted methodology for the prediction of channel-specific rate constants as a function of temperature and pressure suitable to be used for the kinetic modeling of 1,3-butadiene oxidation and of systems where 1,3-butadiene is an important intermediate.

[The value of synthetic MRI in differential diagnosis of benign and malignant breast lesions].

Objective: To explore the diagnostic value of synthetic magnetic resonance imaging (syMRI) quantitative parameters for benign and malignant breast lesions. Methods: From September 2018 to March 2019, a total of 43 cases of breast lesions which were confirmed by surgery and pathology in Cancer Hospital, Chinese Academy of Medical Sciences were enrolled in this study. All patients underwent syMRI sequence scans before and after enhancement except for conventional T2WI, DWI, and enhancement scans. GE AW4.7 workstation was used to generate syMRI parameter maps (T1, T2, proton density mappings), and ITK-SNAP software was used to delineate the volume of interest. The T1, T2, PD values before and after dynamic contrast enhanced (DCE) were obtained, and the change values of each parameter were calculated. Meanwhile, the apparent diffusion coefficient (ADC) and time intensity curve (TIC) of the lesions were measured. The differences of each parameter value were compared between benign and malignant breast lesions, and the receiver operating characteristic (ROC) curve was used to analyze the diagnostic performance of each parameter. Results: Among the 43 enrolled cases, 13 were benign and 30 were malignant. Among the syMRI parameters, the pre-enhancement parameters including T1pre (median 1 663.07 ms), T2pre (median 103.33 ms), post-enhancement parameters ΔT1 (median 1 022.68 ms) and ΔT2 (median 27.67 ms) of benign group, significantly higher than those of the malignant group (the medians were 1 141.74, 92.53, 664.95, and 16.19 ms, respectively, P<0.05). The ADC value of the benign group (median 1.66×10(-3)mm(2)/s) was significantly higher than that of the malignant group (median 1.00×10(-3)mm(2)/s, P<0.05). The benign group included 6 cases of TIC curve type Ⅰ, 5 cases of type Ⅱ, and 2 cases of type Ⅲ. The malignant group included 2 cases of TIC curve type Ⅰ, 17 cases of type Ⅱ, and 11 cases of type Ⅲ. The difference between the two groups was statistically significant (P<0.05). The area under the ROC curve (AUC) of T1pre before DCE was 0.869, higher than 0.806 of ADC and 0.697 of TIC. When the best cut-off value of 1 282.94 ms was chosen, the sensitivity and specificity of diagnosis were 76.9% and 93.3%, respectively. The combination of T1pre and T2pre can further improve the diagnostic performance (AUC=0.908). Conclusions: Among the syMRI quantitative parameters, T1pre, T2pre, ΔT1 and ΔT2 have good value for the differential diagnosis of benign and malignant breast lesions. T1pre has the best diagnostic performance, and the combination of T1pre and T2pre can further improve the diagnostic performance.

[MRI associated biomarker analysis for diagnosis of lymph node metastasis in T1-2 stage rectal cancer].

Objective: To explore the diagnostic accuracy improved by magnetic resonance imaging (MRI) biomarkers for lymph node metastasis in T1-2 stage rectal cancer before treatment. Methods: Medical records of 327 patients with T1-2 rectal cancer who underwent pretreatment MRI and rectal tumor resection between January 2015 and November 2019 were retrospectively analyzed. Fifty-seven cases were divided into the lymph node metastasis group (N+ group) while other 270 cases in the non-lymph node metastasis group (N-group) according to the pathologic diagnosis. Two radiologist evaluated the tumor characteristics of MRI images. The relationship of the clinical and imaging characteristics of lymph node metastasis was assessed by using univariate analysis and multivariable logistic regression analysis. Receiver operating characteristic (ROC) curve was used to evaluate the diagnostic abilities for the differentiation of N- from N+ tumors. Results: Among the 327 patients, MR-N evaluation was positive in 67 cases, which was statistically different from the pathological diagnosis (P<0.001). The sensitivity, specificity and accuracy of MRI for lymph node metastasis were 45.6%, 84.8% and 78.0%, respectively. Multivariate regression analysis showed that tumor morphology (P=0.002), including mucus or not (P<0.001), and MR-N evaluation (P<0.001) were independent influencing factors for stage T1-2 rectal cancer with lymph node metastasis. The area under the ROC curve of rectal cancer with lymph node metastasis analyzed by the logistic regression model was 0.786 (95%CI: 0.720~0.852). Conclusions: Tumor morphology, including mucus or not, and MR-N evaluation can serve as independent biomarkers for differentiation of N- and N+ tumors. The model combined with these biomarkers facilitates to improve the diagnostic accuracy of lymph node metastasis in T1-2 rectal cancers by using MRI.

[The value of MR T2WI signal intensity related parameters for predicting pathological complete response to neoadjuvant chemoradiotherapy in locally advanced rectal cancer].

Objective: To evaluate the value of T2WI signal intensity related parameters that can be obtained by magnetic resonance imaging (MRI) for predicting pathological complete response (pCR) after neoadjuvant chemoradiotherapy (nCRT) in patients with locally advanved rectal cancer (LARC). Methods: Signal Intensity of Tumor (SIT) and Signal Intensity of Tumor/Muscle (SIT/M) of MR T2WI before and after neoadjuvant chemoradiotherapy of 101 patients with locally advanced rectal cancer were evaluated by two experienced readers independently. Signal Intensity of Tumor Reduction Rate (SITRR) and Signal Intensity of Tumor/Muscle Reduction Rate (SIT/MRR) were calculated. The difference of related parameters of T2WI tumor signal intensity between the pCR and the non-pCR group were analyzed. Receiver operating characteristic (ROC) analysis was used to assess the diagnostic performance for predicting pCR. Results: Of the 101 patients, 18 were in pCR group and 83 were in non-pCR group. In all patients, the SITpre, SITpost, SITRR, SIT/Mpre, SIT/Mpost and SIT/MRR measured by reader 1 were 197.0 (133.0), 144.2 (69.7), 0.4% (0.5%), 2.6 (0.6), 3.0 (2.3) and 0.4 (0.2)% in pCR group, and 227.0 (99.0), 205 (95.4), 0.1% (0.6%), 2.6 (0.6), 2.6 (1) in non-pCR group, respectively. SITpre, SITpost, SITRR, SIT/Mpre, SIT/Mpost and SIT/MRR measured by reader 2 were 193.0 (135.0), 143.0 (69.8), 0.4% (0.2%), 2.6 (0.6), 1.5 (0.5) and 0.39% (0.2%) in pCR group, and 234.0(108.0), 203(96.5), 0.1% (0.3%), 2.6 (0.6%), 1.7 (0.7) and 0.25% (0.2%) in non-pCR group, respectively. Between the pCR and non-pCR group, there were significant differences in SITpost, SIT/Mpost and SIT/MRR measured by both readers (all P<0.01), but there was no significant differences in SITpre and SIT/Mpre (P>0.05). The difference of SITRR measured by reader 1 was not statistically significant (P=0.415), while the difference of SITRR measured by reader 2 was statistically significant (P=0.001). In patients with rectal non-mucinous adenocarcinoma, SITpost, SIT/Mpost, SITRR and SIT/MRR measured by two physicians were still statistically significant between the pCR and non-pCR group (all P<0.01), but SITpre and SIT/Mpre had no significant difference (P>0.05). ROC curve analysis showed that in all patients, the area under curve (AUC) of SITpost, SIT/Mpost and SIT/MRR for predicting pCR to neoadjuvant chemoradiotherapy in locally advanced rectal cancer was 0.694-0.762, the sensitivity was 68.2%-77.3%, and the specificity was 63.6%-77.3%. In rectal non-mucinous adenocarcinoma patients, the AUC, sensitivity and specificity was 0.704-0.764, 62.7%-78.9% and 66.2%-84.2%, respectively. Conclusions: T2WI signal intensity related parameters are potential predictors for pCR in locally advanced rectal cancer after neoadjuvant chemoradiptherapy. The predictive value is higher in non-mucinous adenocarcinoma.

[Preclinical application of MR and fluorescent dual-modality imaging combined with photothermal therapy in HER-2 positive breast cancer].

Objective: To construct superparamagnetic iron oxide nanoparticles (SPIONs) coated on trastuzumab and indocyanine green (ICG) and then investigate whether the coated nanoparticles (NPs) targeted to human epidermal growth factor receptor-2 (HER-2) receptors on breast cancer cells in vitro and in vivo. Methods: The Fe(3)O(4)-trastuzumab-ICG NPs were constructed. And a series of characteristics of the NPs were evaluated. The uptake ability of SK-BR-3, a HER-2 positive breast cancer cell, was observed by transmission electron microscopy. Then the NPs were injected in the tail veins of SK-BR-3 xenograft tumor-bearing mice to observe the aggregation of NPs in the tumor sites by MRI and fluorescent imaging. Furthermore, when the NPs was gathered at the tumor sites, the near infrared thermal imaging system was used to monitor the tumor temperature after the near infrared radiation. Results: The successfully constructed Fe(3)O(4)-trastuzumab-ICG NPs had the size of (25.93±4.25) nm. The absorption peak was 828 nm, which was as same as the emission wavelength of ICG. The NPs had a high relaxation rate of approximately 107.65 mM(-1)·s(-1). The maximum temperature of NPs solution could reach to 57.8℃ after continuous near infrared laser irradiation. The transmission electron microscopy imaging revealed that the NPs could target and enter into the endoplasmic reticulum of SK-BR-3 cells. MRI analysis showed the lowest T(2) relaxation time in the tumor sites 24 h after tail vein injection of the NPs. The △T(2) of the tumor sites in the Fe(3)O(4)-trastuzumab-ICG group (30.7±4.8) ms was higher compared with that of control group (3.1±1.1) ms, Fe(3)O(4)-IgG-ICG group (4.4±0.9) ms and trastuzumab + Fe(3)O(4)-trastuzumab-ICG group (11.3±3.8) ms., respectively, all showing statistically significant differences (P<0.05). The fluorescence imaging revealed that the NPs was concentrated transiently in the intraperitoneal organs and tumor sites, then excreted into the bladder. After 24 h, there was an obvious aggregation in the tumor sites. The near infrared thermal imaging experiments showed that the temperature of tumor sites in Fe(3)O(4)-trastuzumab-ICG group could go up to 49.4℃ after continuous near infrared light irradiation. Conclusion: The newly constructed Fe(3)O(4)-trastuzumab-ICG NPs have the potential to act as a multifunctional imaging agent and a powerful tool for photothermal therapy for HER-2 positive breast cancer.

[Combined T2-weighted and diffusion-weighted MR imaging for staging of rectal cancers].

Objective: To compare the diagnostic value of T2 weighted imaging (T2WI), diffusion-weighted imaging (DWI), and T2WI+ DWI magnetic resonance imaging (MRI) for staging of rectal cancers for improving the accuracy of tumor staging. Methods: From January 2011 to December 2013, 120 cases of rectal cancers proved by colonoscopy without receiving any anti-tumor treatment were enrolled retrospectively. The MRI data for these patients were divided into three groups, ie., T2WI, DWI and T2WI+ DWI, for evaluating the tumor stages. The results were compared with histopathologic findings. The sensitivity and specificity were calculated and compared with chi-square test. The nodal staging was predicted by using T2WI+ DWI. Results: The accuracy for prediction of tumor staging was 83.3%, 65.0% and 92.5% for T2WI, DWI, and T2WI+ DWI respectively. The specificity for evaluating T1 and T2 stage, and the sensitivity for evaluating T3 by DWI was significantly lower than those using T2WI and T2WI+ DWI in rectal cancers. The sensitivity for evaluation of T2 by DWI was lower than that using T2WI+ DWI (63.0% vs. 88.9%). The sensitivity for evaluation T2 and specificity for T3 by T2WI+ DWI was higher than thouse using T2WI only (88.9% vs. 51.9%, 94.0% vs. 72.0%). The accuracy for prediction of nodal staging by using T2WI+ DWI was 62.1% (72/116). Conclusions: T2WI is the key sequence for staging of rectal cancers. Although the diagnostic accuracy was not good by using DWI alone, the combination of T2WI and DWI can improve the accuracy significantly for tumor staging in rectal cancers, whereas the nodal staging was still a hard task for radiologists.

[Measurement reproducibility of parameters derived from introvoxel incoherent motion diffusion-weighted MRI imaging of rectal cancer].

Objective: To study the measurement reproducibility of parameters derived from introvoxel incoherent motion (IVIM) diffusion-weighted imaging (DWI)-MRI of rectal cancer between- and within- radiologists. Methods: Clinical data of 34 patients with rectal cancer were prospective analyzed. Conventional MRI sequences, IVIM DWI-MRI with sixteen b values and dynamic contrast enhancement (DCE)-MRI sequences of rectum were acquired by GE 3.0-T MRI imager. The IVIM sequence images with b value=1000 sec/mm(2) were selected to measure the maximum axial section of tumor by a radiologist with 15 year-experiences in gastrointestinal cancer imaging.Two radiologists (radiologist 1 and radiologist 2 with 2 and 10 years of experience in gastrointestinal cancer imaging, respectively) independently draw a freehand region of interest (ROI) that contained the largest available tumor area on the selected section. Monoexponential apparent diffusion coefficient (ADC) and biexponential IVIM metrics maps and IVIM parameters were generated automatically by the software. The repeated measurement was performed at an interval of one week. The average values of each measurement were used for statistical analysis. ADC values and IVIM parameters obtained between- and within- radiologists were analyzed by Wilcoxon signed-rank test. Intraclass correlation coefficients (ICC) and Bland-Altaman plots were used to analyze the parameter reproducibility of two measurements between- and within- radiologists. Results: The first and second measured ADC (×10(-3)mm(2)/s), true diffusivity (D, ×10(-3)mm(2)/s), false diffusivity (D(*,) mm(2)/s) and perfusion fraction (f, %) by radiologist 1 were 0.997, 0.692, 0.043, 34.6 and 0.993, 0.691, 0.038, 32.8, respectively. The first and second measured ADC (×10(-3)mm(2)/s), D (×10(-3)mm(2)/s), D(*) (mm(2)/s), f (%) by radiologist 2 were 0.987, 0.651, 0.046, 32.8 and 0.996, 0.689、0.041, 32.7, respectively. No statistically significant differences were observed in ADC and IVIM parameters obtained between- and within- radiologists (P>0.05). The ADC values and the f values of two times were significantly correlated between- and within- radiologists. The D values were significantly correlated within a radiologist, and the correlation of D(*) values within a radiologist was significantly higher than that between radiologists. The 95% limits of agreement (LoA) of ADC values and f values were smaller than those of D values and D(*) values between- and within- radiologists. The 95% LoA of ADC values was the least, while that of D(*) values varied most.The 95% LoA of f values and D values kept steady within a radiologist, and 95% LoA of f values was slightly smaller than that of D values. The 95% LoA of IVIM parameters (ADC, D, f, D(*) values) within radiologists 2 were better than those within radiologist 1. Conclusions: The reproducibilities of ADC and f values are the best, while the reproducibility of D(*) values is relatively poorer in rectal cancer. Measurement reproducibility of parameters derived from IVIM may be improved by increasing radiologists' experiences in drawing ROI.

[The quantitative analysis of MR dynamic contrast-enhangced imaging on efficacy and prognosis of transcatheter arterial chemoembolization on hepatocellular carcinoma].

Objective: To investigate the prognostic value of quantitative parameters of dynamic contrast-enhangced MR (DCE-MR) on short-term efficacy of transcatheter arterial chemoembolization (TACE) on hepatocellular carcinoma(HCC). Methods: 79 patients with HCC underwent non-enhanced MR imaging and DCE on a 3.0T MR scanner before and one month after TACE. The quantitative parameters were measured on the maximal tumor region, including maximal tumor diameter(MTD), ADC, K(trans,) K(ep) and V(e) value before and after TACE. All patients were divided into stable group (36 patients) and progressive group (43 patients) based on follow-up. The quantitative data of the two groups before and after TACE was collected for analysis. Results: Among the 79 lesions in 79 patients, 21 were located in the left lobe of the liver, 53 in the right lobe of the liver and 5 in the junction area of the hepatic lobe. The maximum tumor diameter (MTD) was 2.2-9.9 cm, the median MTD was 5.1 cm. There were significant differences between progressive group and the stable group in MTD, K(trans,) K(ep) values of the tumor before TACE (P<0.05). One month after TACE, the MTD, K(trans,) K(ep,)ΔMTD, ΔK(trans) and ΔK(ep) values of the tumor in progressive group were statistically different with the stable group (P<0.05, respectively). For all the patients, the pre-TACE MTD, AFP, K(trans) and K(ep) values of tumors were statistically different with the post-TACE values (P<0.05). Conclusion: The quantitative parameters (K(trans,) K(ep,)ΔK(trans) and ΔK(ep) values) of the DCE-MR could predict and evaluate the short-term efficacy of TACE on HCC.

[Texture analysis based on contrast-enhanced MRI can predict treatment response to neoadjuvant chemotherapy of breast cancer].

Objective: To investigate whether texture analysis based on contrast-enhanced MRI can predict pathological complete response of locally advanced breast cancer undergoing neoadjuvant chemotherapy(NAC). Methods: Forty-seven patients with breast cancer undergone neoadjuvant chemotherapy from January 2015 to February 2016 were divided into pathological complete response (pCR) group or non-pathological complete response (non-pCR) group based on surgical pathology. Their parameters of texture analysis based on MRI before neoadjuvant chemotherapy and after 2 cycles of treatment were analyzed. Parameters(Energy, Entropy, Inertia, Correlation, Inverse Difference Moment)before and after 2 cycles of NAC between pCR and non-pCR groups were compared using Student t or Wilcoxon rank sum test. The diagnostic performance of different parameters was judged by the receiver-operating characteristic (ROC) curve analysis. Results: The post-NAC value was significantly different from that of pre-NAC (all P<0.05). Pre-treatment parameters (Energy, Entropy, Inertia, Correlation, Inverse Difference Moment) were 78.58×10(-5)(55.64×10(-5), 135.23×10(-5)), 10.06 ± 1.02, 7 993.91±2 428.10, (4.76±0.99) ×10(-5) and (18.10±4.13) ×10(-3) in pCR group, and 76.84×10(-5) (48.68×10(-5), 154.15×10(-5)), 10.28±1.26, 7 184.77 (4 938.03, 9 974.04), (5.21±2.01) ×10(-5) and (17.68±5.87) ×10(-3) in non-pCR group. No significant difference was found between both groups. (P>0.05 for all). At the end of the second cycle of NAC, parameters(Energy, Entropy, Inertia, Correlation, Inverse Difference Moment) were (542.11±361.04) ×10(-5,) 7.95±1.28, 16 765.08±97 06.56, (0.43±0.07) ×10(-5,) and (12.18±9.82) ×10(-3) in pCR group, and 133.00×10(-5) (79.80×10(-5,) 239.00×10(-5)), 9.29±1.46, 7 916.64(6 418.89, 10 934.40), (0.38±0.08) ×10(-5) and (14.80±5.06) ×10(-3) in non-pCR group. At the end of the second cycle of NAC, there was significant difference in the parameters (Energy, Entropy, Inertia, Correlation) and Δparameters (ΔEnergy, ΔEntropy, ΔInertia, ΔInverse Difference Moment) between both groups (P<0.05 for all). The area under curve (AUC) of post-treatment ΔEntropy was 0.81, which was the largest one among parameters. Sensitivity of ΔEntropy for predicting pCR was 75.0% and specificity was 85.7%, respectively. Conclusion: Texture analysis based on dynamic contrast-enhanced MRI can predict early treatment response in primary breast cancer.

[Value of digital breast tomosynthesis (DBT) in the diagnosis of breast lesions].

Objective: To assess the value of digital breast tomosynthesis (DBT) in the diagnosis of breast lesions. Methods: Two hundred and fifty-three breast lesions in 250 patients were selected in this study. All lesions were confirmed pathologically. Preoperative diagnosis was performed independently with full-field digital mammography (FFDM), DBT and DBT plus FFDM, respectively. The diagnostic value of DBT for breast lesions was evaluated based on the pathological diagnosis as the gold standard. The diagnostic performance of DBT and FFDM for breast lesions was compared between the groups with different ages, mammary gland densities and hormone levels. The sensitivity of DBT and FFDM was compared between the groups with different pathological types and different sizes of breast cancer. The correlation between the longest diameter of breast cancers and pathological measurements shown on DBT and FFDM was analyzed. Results: The areas under ROC curves were 0.890, 0.833 and 0.890 for DBT, FFDM and DBT plus FFDM, respectively. The areas under ROC curves for DBT or DBT plus FFDM were significantly greater than that for FFDM (P<0.05). In the group with breast density>50%, group with age ≤50 and non-menopause group, all the areas under ROC curves for DBT or DBT plus FFDM were all significantly larger than that for FFDM (P<0.05). No significant differences were observed in the group with breast density ≤50%, group with age>50 and menopause group (P>0.05). The sensitivity for both DBT and FFDM in the diagnosis of carcinoma in situ was 90.9% (10/11). The sensitivity for DBT and FFDM in the diagnosis of non-carcinoma in situ was 92.3% (120/130) and 83.8% (109/130), respectively. The sensitivity in the groups with the longest diameter of foci >0 mm but ≤10 mm, >10 mm but ≤20 mm, >20 mm but ≤30 mm, and >30 mm but ≤40 mm were 51.7% (4/7), 93.8% (61/65), 96.7% (30/31) and 100% (11/11), respectively, for DBT, and were 51.7% (4/7), 78.5% (51/65), 93.5% (29/31), and 100% (11/11), respectively, for FFDM. The correlation coefficients between the longest diameter of breast cancers and pathological measurements shown on DBT and FFDM were 0.905 and 0.849, respectively (P<0.001). Conclusions: Compared with FFDM, DBT shows a higher diagnostic efficiency in patients with breast density >50%, age ≤50 years and non-menopause, non-carcinoma in situ, and the longest diameter of lesions >10 mm but ≤ 20 mm. The longest diameter of breast lesions is more accurately shown on DBT.

[Preliminary study on intravoxel incoherent motion (IVIM) imaging in laryngeal and hypopharyngeal squamous cell carcinoma].

OBJECTIVE: To evaluate the diagnostic performance of bi-exponential modeling of intravoxel incoherent motion (IVIM) imaging for laryngeal and hypopharyngeal carcinoma. METHODS: A total of 32 patients with pathologically proven laryngeal and hypopharyngeal squamous cell carcinoma were included in this study from November 2014 to August 2015.All patients underwent IVIM-DWI by using twelve b values (0, 10, 20, 30, 50, 70, 100, 150, 200, 400, 800 and 1 000 s/mm(2)). Using the IVIM approach, D, D(*) and f values were extracted using a bi-exponential fit.These quantitative parameters of primary carcinoma and normal pharyngeal tissue were compared.Statistical methods were used to assess differences between the tumor and normal pharyngeal tissue. RESULTS: There were no significant differences of D (P=0.903) and f (P=0.223) values observed among laryngeal carcinoma and hypopharyngeal carcinoma, and D(*) value was significantly different among the two groups (P=0.028). The values of D, D(*,) and f for primary carcinoma were (0.84±0.22)×10(-3) mm(2)/s, (65.71±19.66)×10(-3) mm(2)/s, and 45%±14%, respectively; for normal pharyngeal tissue were (1.48±1.04)×10(-3) mm(2)/s, (37.85±14.04)×10(-3) mm(2)/s, and 36%±12%, respectively (P=0.001, 0.000, and 0.006, respectively). Setting D value 0.949×10(-3) mm(2)/s was threshold to distinguish abnormal and normal tissues, the sensitivity, specificity and accuracy were 91.2%, 88.2% and 92.5%, respectively.There was no statistically significant difference of D and f values(both P>0.05)in different pathological grades of primary carcinoma, and there was statistically significant difference in D(*) values found among the different pathological grades of primary carcinoma (P=0.001). There were statistically significant differences in D(*) values between the well differentiated group and the other two group (both P<0.05), and there was no statistically significant difference between the moderately differentiated group and poorly differentiated group (P>0.05). CONCLUSION: IVIM parameters can reflect the difference between laryngeal and hypopharyngeal carcinoma and normal pharyngeal tissue, and the D value has the best diagnostic performance.D(*) value in different pathological grades of laryngeal and hypopharyngeal squamous cell carcinoma is distinct, and it could reflect the pathological grade of tumor to some extent.

[Value of diffusion-weighted magnetic resonance imaging in prediction of the response to preoperative chemoradiotherapy in rectal carcinoma].

OBJECTIVE: To investigate the value of diffusion weighted imaging (DWI) in predicting the efficacy of preoperative chemoradiotherapy (CRT) for locally advanced rectal cancer. METHODS: From 2007 to 2012, 86 patients with histopathologicaIly proven rectal cancer who underent pre-CRT were enrolled in this study prospectively. Diffusion-weighted MRl was performed in all patients before pre-CRT, while it was performed in part of the patients during and after pre-CRT as well.ADC values of the tumors were calculated on the workstation. Patients were assigned to the tumor downstaged group or the tumor nondownstaged group on the basis of T staging. The change in ADC following treatment and the difference in ADC between groups were analyzed. RESULTS: Of the 86 patients after surgery, 20 were diagnosed with T0, 2 with T1, 17 with T2, 44 with T3 and 3 with T4. 39 patients were classified as the downstaged group, of which 18 were of pCR. The remaining 47 patients were classified as the nondownstaged group. Of the total of 86 patients, the mean ADC values before, during, and after pre-CRT (pre-ADC, during-ADC, and post-ADC) were (1.03±0.17)×10(-3), (1.39±0.28)×10(-3), and (1.61±0.27)×10(-3) mm(2)/s and there was a significant difference (P<0.001). However, the pre-CRT ADC of the downstaged group did not differ significantly from that of the nondownstaged group (P=0.615). Of the 43 patients who underwent MRI before, during and after pre-CRT, the mean ADC values were (1.05±0.16)×10(-3), (1.39±0.29)×10(-3)and (1.67±0.30)×10(-3) mm(2)/s, respectively, showing a significant difference (P<0.001)as well. CONCLUSIONS: The mean ADC value of rectal cancer is gradually increasing along with the course of chemotherapy. Pre-ADC is not a good parameter to be used to predict the efficacy of pre-CRT for locally advanced rectal cancer.

Myomatous hepatic angiomyolipoma: imaging findings in 14 cases with radiological-pathological correlation and review of the literature.

OBJECTIVE: To display and analyse the imaging features of myomatous hepatic angiomyolipomas (MHAMLs). METHODS: The imaging features (CT = 9; MRI = 10; ultrasound = 10; contrast-enhanced ultrasound = 4) of 14 patients with pathologically proven MHAMLs were reviewed retrospectively. RESULTS: MHAMLs were surgically resected in the 14 patients (10 females and 4 males; age, 27-64 years; mean, 45 years), all of whom had negative hepatitis markers and were positive for the immunohistochemical stain homatropine methylbromide-45. The tumours were solitary and well defined, and ranged in size from 1.9 to 9.1 cm (mean, 5.7 cm). On dynamic contrast-enhanced CT, MRI and ultrasound scans, all tumours showed fast strong enhancement in the arterial phase and moderate washout in the portal venous and delayed phases, and the greater portions of the tumours were slightly lower than the surrounding hepatic parenchyma. In some cases, a small area of prolonged or increasing enhancement in the tumour was recognized in the delayed phase. Early draining vessels to the portal vein or hepatic vein could be seen in some cases. However, no capsular signs could be confidently identified in the delayed phase. Haemorrhagic cavities were recognized in two cases, and nodular low-intensity areas in the tumours on T2 weighted imaging that showed slow and faint enhancement on dynamic scans were seen in two cases. However, no necrosis was identified. CONCLUSION: Dynamic enhanced imaging studies revealed some specific features of MHAMLs that distinguish them from other hypervascular hepatic tumours, especially when combined with clinical features. Familiarity with imaging and clinical features of MHAMLs could avoid unnecessary surgical resection of these generally benign tumours. ADVANCES IN KNOWLEDGE: This article systematically describes the imaging features of MHAMLs.

Methylation-sensitive amplification polymorphism analysis of fat and muscle tissues in pigs.

DNA methylation may be involved in regulating the expression of protein-coding genes, resulting in different fat and muscle phenotypes. Using a methylation-sensitive amplified polymorphism approach, we obtained 7423 bands by selective amplification of genomic DNA from six different fat depots and two heterogeneous muscle types from Duroc/Landrace/Yorkshire cross-bred pigs. The degrees of DNA methylation, determined by the percentages of hemi- and fully methylated sites relative to the total number of CCGG sites, were similar in male and female pigs for each specific tissue [χ(2) test; P (two-tailed) > 0.05]. Gender bias was therefore ignored. There were significant differences in the degree of DNA methylation among the eight tissue types [χ(2) test; P(total) (two-tailed) = 0.009]. However, similar degrees of methylation were observed among the six fat depots [χ(2) test; P(fat) (two-tailed) = 0.24 > 0.05]and between the two muscle types [χ(2) test; P(muscle) (two-tailed) = 0.76 > 0.05]. We conclude that the degree of DNA methylation differs between porcine fat and muscle tissue, but that the methylation status of a particular tissue type is similar, despite being deposited at different body sites.

Preparation and growth mechanism of lead telluride nanocrystals by a modified molten composite-hydroxides method.

PbTe nanocrystals were prepared by a modified molten composite-hydroxides method at 180 degrees C for different times, using Pb(NO3)2 and TeO2 as starting materials and KBH4 as a reductant. The nanocrystal structure and morphologies of the synthesized products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and high resolution TEM (HRTEM), respectively. The results showed that the reaction time has a significant influence on the size and shape of the as-prepared PbTe nanocrystals. As the reaction time increased, the as-prepared products were eventually transformed from nanomaterials (nanocubes, nanorods, and nanosheets) to microcrystals with different morphologies (microcubes, mciroprisms, and microplates). The formation mechanism of the PbTe was proposed, and a one-dimensional oriented attachment growth process combined with two-dimensional oriented attachment growth process was suggested for the growth of nanorods and nanosheets.

Synthesis and preliminary testing of molecular wires and devices.

Presented here are several convergent synthetic routes to conjugated oligo(phenylene ethynylene)s. Some of these oligomers are free of functional groups, while others possess donor groups, acceptor groups, porphyrin interiors, and other heterocyclic interiors for various potential transmission and digital device applications. The syntheses of oligo(phenylene ethynylene)s with a variety of end groups for attachment to numerous metal probes and surfaces are presented. Some of the functionalized molecular systems showed linear, wire-like, current versus voltage (I(V)) responses, while others exhibited nonlinear I(V) curves for negative differential resistance (NDR) and molecular random access memory effects. Finally, the syntheses of functionalized oligomers are described that can form self-assembled monolayers on metallic electrodes that reduce the Schottky barriers. Information from the Schottky barrier studies can provide useful insight into molecular alligator clip optimizations for molecular electronics.

[Construction of gene targeting vector for duplicating p35Nck5a gene and its application in the gene targeting of ES cells].

To duplicating the regulatory subunit p35Nck5a gene of mouse neuronal cdc2-like kinase in embryonic stem (ES) cells, about 12.2 kb of pGDTV vector for p35Nck5a gene duplication was constructed. The linearized pGDTV vectors were transfected into ES cells by electroporation. 245 drug-resistant cell clones were obtained in both G418 and GANC medium and the frequency of surviving cells was 6.22 x 10(-5). The ES cell clones were identified to have duplicated the p35Nck5a gene by use of both PCR and genomic Southern blotting, and the frequency of homologous recombination is 5.08 x 10(-7). The use of negative selection gene (HSV-tk) results in 7-fold increase at selection efficiency. This study lays the foundations of preparing mouse models of Alzheimer's disease.

Pulmonary airway reopening: effects of non-Newtonian fluid viscosity.

This paper considers the effects of non-Newtonian lining-fluid viscosity, particularly shear thinning and yield stress, on the reopening of the airways. The airway was simulated by a very thin, circular polyethylene tube, which collapsed into a ribbon-like configuration. The non-Newtonian fluid viscosity was described by the power-law and Herschel-Buckley models. The speed of airway opening was determined under various opening pressures. These results were collapsed into dimensionless pressure-velocity relationships, based on an assumed shear rate gamma = U/(0.5 H), where U and H are the opening velocity and fluid film thickness, respectively. It was found that yield stress, like surface tension, increases the yield pressure and opening time. However, shear thinning reduces the opening time. An increased film thickness of the non-Newtonian lining fluid generally impedes airway reopening; a higher pressure is needed to initiate the airway reopening and a longer time is required to complete the opening process.