依诺沙星与铁配合物的合成、表征及其生物活性

由水热法合成了依诺沙星铁配合物,用固体培养基平板药敏试验方法测定了配合物的体外抗菌活性。结果表明,合成的依诺沙星铁配合物对金黄色葡萄球菌、肺炎链球菌、绿脓杆菌、白色念珠菌都具有抗菌活性,但只有对金黄色葡萄球菌和绿脓杆菌的抗菌活性强于配体本身。     

1-芳基亚甲基-2-(6-(3,5-二甲基-1H-吡唑-1-基)-1,2,4,5-四嗪-3-基)肼的合成及抗菌活性

以水合肼和硝酸胍为原料,经过环合、氧化和肼化,得到3-(3,5-二甲基-1H-吡唑-1-基)-6-肼基-1,2,4,5-四嗪(4),以此为原料和不同芳香醛发生腙化反应,得到系列1-芳基亚甲基-2-(6-(3,5-二甲基-1H-吡唑-1-基)-1,2,4,5-四嗪-3-基)肼(5),产物经元素分析、1H NMR、IR和MS表征。所合成的系列化合物抗菌活性测试表明,它们对大肠杆菌、金黄色葡萄球菌、枯草杆菌等3种细菌表现出一定程度的抑制活性。     

Fiber Optic Sensors: Recent Developments

Abstract

Biosensors are attracting the attention of many investigators in the field of biotechnology related research. A biosensor is a device that combines the specificity of a biomaterial (enzymes, antibodies, receptors or even whole cells) with sensitive, well established bioassays. Biosensors are of potential use in many fields including clinical and biotechnology monitoring. An important class of enzymes, effecting H₂O₂ generation or O₂ depletion, can be monitored by following the enzymatic reaction, and thus determining the substrate level. Other enzyme systems, like urease and penicillnase, result in a pH change which can be followed using a pH sensitive device. For the many advantages of fiber optic sensing, extensive research effort have been devoted to the production of reliable, self contained and sensitive fiber optic biosensors which are capable of in situ monitoring. An over view of the possibilities and challenges associated with the construction of such sensors are discussed.     

Q‐switched and modelocked all‐fiber lasers based on advanced acousto‐optic devices

The interest in all‐fiber lasers is stimulated by the inherent advantages they have over bulk lasers in aspects such as heat dissipation and robustness. The performance of Q‐switched and modelocked fiber lasers can benefit enormously from the development of all‐fiber configurations. A fiber laser with strictly all‐fiber components can fulfil the requirements of mechanical stability, low maintenance, enhanced power efficiency, simplified assembly process, and low cost. In this framework, recent developments infiber acousto‐optic devices are reviewed that have demonstrated new possibilities for actively Q‐switched distributed feedback fiber lasers, modelocking lasers and doubly active Q‐switched modelocked lasers. The aim is to demonstrate the great potential of infiber devices for the active control of different types of fiber lasers.     

Characterization of Chitosan-Gelatin Blend Scaffolds

Vacuum freeze-drying was used to prepare chitosan-gelatin (CG) scaffolds from hydrogels, with glutaraldehyde (GA) used as a crosslinker. The effects of the changes in volume ratios of the 2?wt% CG and GA solutions on scaffold performance were studied. The ratio of chitosan to gelatin solution volumes, vr(C/G), was adjusted to 1/2 or 1/1, with the 0.25?wt% GA volume at 3, 6, or 8% of the CG/GA volume. Six groups of CG scaffolds were fabricated and the scaffolds performance compared. After the cells were incubated for 4?days, hematoxylin eosin (HE) staining was used to observe the spreading of human skin keratinocyte (HaCaT) cells on these scaffolds, with the MTT method also used to detect the cells proliferation. The inhibition zone method was used on cells cultures to determine the antibacterial properties of the scaffolds against S. aureus and E. coli. Scaffolds were also examined for degradation in lysozyme and their compression properties were tested after degradation. The results showed that the HaCaT cells grew well on these scaffolds and proliferated significantly, indicating that these scaffolds possessed good cytocompatibility. With increased chitosan volume, the antibacterial properties of the scaffolds against S. aureus increased, however, there was no significant change in the antibacterial properties toward E. coli. Increased volumes of chitosan and GA decreased the scaffolds degradation rates and improved the elastic compressive moduli of the scaffolds after degradation. The scaffolds in the vr(C/G) = 1/1, 8% GA group have potential application prospects in the field of skin regeneration.     

Simulation Results for DWDM Systems with Ultra-High Capacity

We present stimulation results for DWDM systems with an ultra-high capacity up to 1.28 Tbit/s and spectral efficiency approaching 0.4 bit/s/Hz. The impact of signal-to-noise ratio (SNR) on parameters such as channel spacing, length of fiber, dispersion, and number of channels has been investigated and the results obtained have been explained on the basis of fiber nonlinear effects. It has been shown that with an increase in channel spacing, the SNR increases to the maximum optimum value and then decreases to a steady value. With an increase in number of channels, the SNR decreases for small wavelength spacing. For large wavelength spacing, it becomes independent of the number of channels. Keeping channel spacing constant, the SNR decreases with an increase in the length of the fiber. The SNR also improves with a small increase in dispersion of the fiber. Further, it is observed that, with increase in length over dispersion-shifted fiber, the received power decreases and the bit error rate increases.     

Simplified Formula of Bending Loss for Optical Fiber Sensors

A simple fiber-optic bending loss formula is achieved for optical fiber sensors. This simple formula considers various bending radii, number of turns, extra bending angle, and wavelength and has good agreement with theoretical and experimental data. We also propose a simplified formula for sensitivity of the fiber-optic bending loss in this article. The defined sensitivity formula has the benefit of showing parameters for fiber-optic bending sensor systems.     

Suppression of Output Power and NF Excursions in Cascades of Highly Inverted EDFAs with Packet-Switched Traffic

Significant output power excursions in cascades of erbium-doped fiber amplifiers (EDFAs) can cause serious problems in wavelength division multilexing (WDM) packet-switched burst-mode networks. Signal power excursions more serious than those induced by channel addition/removal in circuit switched networks can arise when data on the WDM channels is highly variable in nature. Self-similar traffic can be subject to large variation in EDFA gain. In order to prevent unacceptable error bursts, due, for example, to channel power becoming too low to preserve adequate eye opening or exceeding thresholds for optical nonlinearities, the channel power should be maintained constant. In this letter, it is shown that the sizable power and noise figure swings arising in a cascade of EDFAs with WDM burst-mode packet-switched networks with self-similar traffic can be effectively suppressed when highly inverted amplifiers are employed. The analysis is based on the application of a numerical model, which solves the transcendental equation for length averaged metastable level population of an EDFA.     

Fiber-Grating-Based Optical Limiting Amplifier Module for Dual-Wavelength,Hybrid Data Rate Transmission

A multichannel fiber-grating-based optical limiting amplifier module is proposed. Dual-wavelength, hybrid data rate transmission is demonstrated with 30 dB input dynamic range. For 5.0 and 2.5 Gbit s dual-channel transmission in a 200 km single-mode fiber, power penalty due to gain competition between channels and backreflection noise is less than 0.6 dB compared to the receiver sensitivity of 0 km, 5.0 Gbit per second single-channel operation.     

Fiber optics in japan

Abstract

This paper describes the recent progress in research and development of fiber optics in Japan. A review is presented of recent developments in fiber manufacturing, cabling, and fiber splicing. Experimental results are given for an optical communication system with optoelectronic components. Theoretical analysis and fundamental experiments are not included, nor are research activities in such devices as lasers or in such applications as those in medical fields. Transmission characteristics of optical fibers—in particular loss and pulse spreading—are assessed from the viewpoint of their structures. Various methods of fiber strengthening and structuring cables are described from the viewpoint of mechanical strength. Coupling efficiencies of detachable connectors and methods of permanent fiber splicing are described. Experimental results on optical fiber communication systems are presented and coupling techniques between a light source and an optical fiber are described.