Room-Temperature Organic Negative Differential Resistance Device Using CdSe Quantum Dots as the ITO Modification Layer

Room-temperature negative differential resistance （NDR） has been observed in different types of organic materials. However, detailed study on the influence of the organic material on NDR performance is still scarce. In this work, room-temperature NDR ＆ observed when CdSe quantum dot （QD） modified ITO is used as the electrode. Furthermore, material dependence of the NDR performance is observed by selecting materials with different charge transporting properties as the active layer, respectively. A peak-to-valley current ratio up to 9 is observed. It is demonstrated that the injection barrier between ITO and the organic active layer plays a decisive role for the device NDR performance. The influence of the aggregation state of CdSe QDs on the NDR performance is also studied, which indicates that the NDR is caused by the resonant tunneling process in the ITO/CdSe QD/organic active layer structure.

Broad-Band All-Optical Wavelength Conversion of Differential Phase-Shift Keyed Signal Using an SOA-Based Nonlinear Polarization Switch

Broad-band all-optical wavelength conversion of differential phase-shift keyed （DPSK） signal is experimentally demonstrated. This scheme is composed of a one-bit delay interferometer demodulation stage followed by a semiconductor optical amplifier （SOA） based nonlinear polarization switch. A wavelength converter for the 10 G b/s DPSK signal is presented, which has a wide wavelength range of more than 30 nm. The converted signals experience small power penalties less than 1.4 dB compared with the original signal, at a bit error rate of 10-9. Additionally, the optical spectra, the measured waveforms and the open eye diagrams of the converted signals show a high quality wavelength conversion performance.

Atmospheric NO_2 Concentration Measurements Using Differential Absorption Lidar Technique

Using the Differential Absorption Lidar (DIAL) technique, two types of approaches, namely, reflection from retroreflector / topographic target and backscatter from atmosphere, are available for studying remotely the atmospheric NO, concentration. The Argon ion lidar system at the Indian Institute of Tropical Meteorology (IITM), Pune, India has been used for the measurements by following both the path-averaged and range-resolved approaches. For the former, a topographic target (hill) is used for determining path-averaged surface concentration. In the latter, spectral properties of atmospheric attenuation is used for making range-resolved measurements in the surface layer. The results of the observations collected by following both approaches are presented. The average surface NO2 concentration was found to vary between 0.01 and 0.105 ppm and the range-resolved measurements exhibited higher values suggesting treatment of the lidar data for scattering and extinction effects due to atmospheric aerosols and air molecules, and atmospheric turbulence. Certain modifications that are suggested to the experimental set-up, data acquisition and analysis to improve the measurements are briefly described.

Isolating cDNA clones from rice induced by Magnaporthe grisea using PCR based differential screening method

The differential hybridization technique hasbeen widely used to identify genes that are dif-ferentially expressed.However,this approachhas several drawbacks.First,the screeningprocedures are rather labor-intensive and time-consuming.Second,the amount of phageDNAs transferred onto the two filters may notbe equivalent,which leads to an inaccurate se-lection of a positive clone.Third,isolation ofphage DNA is slow and cumbersome.Here,aPCR based differential screening method that

Differentiation of Positional Isomers of Propyl Alcohols Using Filament-Induced Fluorescence

We experimentally demonstrate the recognition of positional isomers of propyl alcohol vapor through nonlinear fluorescence induced by high-intensity femtosecond laser filaments in air. By measuring characteristic fluorescence of n-propyl and isopropyl alcohol vapors produced by femtosecond filament excitation, it is found that they show identical spectra, that is, those from molecular bands of CH, C2, Nit, OH and CN, while the relative intensities are different. By comparing the ratios of the CH and C2 signals, the two propyl alcohol isomers are differentiated. The different signal intensities are ascribed to different ionization potentials of the two isomer molecules, leading to different production efficiencies of fluorescing fragments.

Differentiation of periapical granulomas and cysts by using dental MRI: a pilot study

The purpose of this pilot study was to evaluate whether periapical granulomas can be differentiated from periapical cysts in vivo by using dental magnetic resonance imaging(MRI). Prior to apicoectomy, 11 patients with radiographically confirmed periapical lesions underwent dental MRI, including fat-saturated T2-weighted(T2 wFS) images, non-contrast-enhanced T1-weighted images with and without fat saturation(T1 w/T1 wFS), and contrast-enhanced fat-saturated T1-weighted(T1 wFS+C) images. Two independent observers performed structured image analysis of MRI datasets twice. A total of 15 diagnostic MRI criteria were evaluated, and histopathological results(6 granulomas and 5 cysts) were compared with MRI characteristics. Statistical analysis was performed using intraclass correlation coefficient(ICC), Cohen’s kappa(κ), Mann–Whitney U-test and Fisher’s exact test. Lesion identification and consecutive structured image analysis was possible on T2 wFS and T1 wFS+C MRI images. A high reproducibility was shown for MRI measurements of the maximum lesion diameter(intraobserver ICC = 0.996/0.998; interobserver ICC = 0.997), for the "peripheral rim" thickness(intraobserver ICC = 0.988/0.984; interobserver ICC = 0.970), and for all non-quantitative MRI criteria(intraobserver-κ = 0.990/0.995; interobserver-κ = 0.988). In accordance with histopathological results, six MRI criteria allowed for a clear differentiation between cysts and granulomas:(1) outer margin of lesion,(2) texture of "peripheral rim" in T1 wFS+C,(3)texture of "lesion center" in T2 wFS,(4) surrounding tissue involvement in T2 wFS,(5) surrounding tissue involvement in T1 wFS+C and(6) maximum "peripheral rim" thickness(all: P < 0.05). In conclusion, this pilot study indicates that radiation-free dental MRI enables a reliable differentiation between periapical cysts and granulomas in vivo. Thus, MRI may substantially improve treatment strategies and help to avoid unnecessary surgery in apical periodontitis.

A new differential absorption lidar for NO_2 measurements using Raman-shifted technique

Based on Raman-shifted wavelengths of D2 and CHr pumped by third harmonic of Nd:YAG laser, a differential absorption lidar was presented in this paper and had been constructed for probing environmental NO2 concentration. NO2 experimental measurements were carried out at Anhui Institute of Optics and Fine Mechanics in Hefei. Some NO2 measurement results were given and discussed.

Enhanced quantitative X-ray phase-contrast images using Foucault differential filters

Several X-ray phase visualization methods are being real- ized for imaging of phase objects, such as biological and polymeric specimens. Grating-based phase-contrast imaging using a source-grating-attached X-ray tube that provides partially coherent X rays is one of the most successful methods in this field.

RAPID DETECTION OF ONCOGENE AMPLIFICATION IN PARAFFIN SECTIONS OF BREAST CARCINOMAS USING QUANTITATIVE DIFFERENTIAL PCR AND FLUORESCENT DNA TECHNOLOGY

Gene amplification is a common mechanism of oncogene activation and contributes to tumor progression. Analysis of such genetic alterations are relevant to the understanding of tumor genetics and could provide prognostic information for the individual patient. Standard analytical approaches using Southern blot and slot blot require a large amount of good

Comparison of diagnostic value of TIRADS,BSRTC,BRAF^(V600E) mutation detection and their combined use in differentiating thyroid nodules

Objective To compare the diagnostic efficiency of the thyroid imaging reporting and data system(TIRADS),the Bethesda system for reporting thyroid cytopathology(BSRTC)and BRAFV600Edetection,and their combined use in the differentiation between benign and malignant thyroid nodules.Methods One hundred

Treating Biliary System Postoperational Complications by Syndrome Differentiation Using Traditional Chinese Medicine

The operation of the biliary system is usually employed for liver, gallbladder or pancreatic diseases. Most benign cases are cholelithiasisinduced cholecystitis and choledochitis, while malignant ones mainly include gallbladder cancers, cholangiocarcinoma orcarcinoma of the head of the pancreas.

Design of all-optical temporal differentiator using a Moir fiber grating

We design and demonstrate an all-optical temporal differentiator based on a simple Moire fiber grating operated in reflection. The simulation results prove that a single Moire fiber grating with only one π-phase shifted point can act as the first-order temporal differentiator and that a Moire fiber grating incorporating two symmetrical π-phase shifted points can act as the second-order temporal differentiator. A practical Moire fiber grating is fabricated, thereby proving that such a grating can act as the first-order temporal differentiator. Our results verify the feasibility, flexibility, and accuracy of the proposed method.