Rapid histologic diagnosis using quick fluorescence staining and tissue confocal microscopy

With the development of advanced and minimally invasive surgical techniques, and in view of the functional and cosmetic aspects, the need for rapid and accurate diagnosis during surgery is increasing. This study was conducted to develop a tissue diagnosis method using confocal microscopy after simple tissue staining that does not require freezing and slicing. At present, fluorescence staining with confocal microscopy is not generalized for real‐time diagnosis during surgery. In this paper, we propose a fluorescence staining method using Hoechst 33342 and Eosin that does not require tissue freezing and slicing. The proposed method can be used as part of a rapid tissue diagnosis method that is suitable for use in the operating room, although further research is required before it can be applied in clinical practice.     

Electromagnetic transmission of an oblique waveguide array

Transverse magnetic (TM) and transverse electric (TE) wave transmissions of an oblique parallel-plate waveguide array is studied. The scattered wave is represented in terms of continuous and discrete modes based on the Fourier transform and series, respectively. The tangential field continuities at the boundary are enforced to obtain simultaneous equations for the discrete modal coefficients. Residue calculus is utilized to transform the radiation field and reflection coefficient into numerically efficient forms. Numerical computations are performed to illustrate the behavior of wave radiation and reception by an oblique waveguide array.     

A pilot study on accelerated sludge degradation by a high-concentration membrane bioreactor coupled with sludge pretreatment.

A new sludge treatment process combining a high MLSS membrane bioreactor with sludge pretreatment techniques was studied in pilot-scale experiments. The membrane bioreactor (MBR) was adopted for high efficiency aerobic digestion. The combination of alkaline-ozone treatment of the mixed liquor in the MBR reactor accelerated the biodegradation process by enhancing biodegradability of the sludge. The hydraulic retention time (HRT) of the reactor was set as 3.1 days and the DO level was 1 mg/L on average. After 5 months of operation, the accumulative total solids reduction was more than 70%. Removal efficiency of volatile solids and non-volatile solids were 76% and 54%, respectively. It was found that a considerable portion of the non-volatile solids was dissolved into ions and then flushed out with the effluent. Also, about 41% and 28% of T-N and T-P in the raw sludge were removed although no biological nutrient removal process was adopted. The experiment was run smoothly without significant membrane fouling, even at the relatively high levels of MLSS concentration (11,000-25,000 mg/L). It is concluded that the newly proposed process can significantly increase the sludge reduction efficiency with much shorter retention times.     

Fracture behavior in medium-carbon martensitic Si- and Ni-steels

A study of fracture behavior in medium-carbon martensitic Ni- and Si-steels has been made. Charpy impact testing was conducted in order to investigate fracture mode as a function of test temperature. Whereas the transgranular cleavage fracture becomes the primary brittle fracture mode with decreasing test temperature in the Si-steel, intergranular fracture is the only brittle fracture mode observed at low temperatures in the Ni-steel. The different fracture behavior between these steels appears to be due to variation in intrinsic matrix toughness. Since Si may impair the intrinsic matrix toughness, the occurrence of transgranular cleavage fracture becomes relatively easy with decreasing test temperature. On the other hand, since Ni may improve considerably the intrinsic matrix toughness, the transgranular cleavage fracture is not able to occur although the test temperature decreases. Thus, the intrinsic matrix toughness can play a significant role in controlling the fracture behavior.     

High-power performance limitation of an ESQW SEED in an AFP etalonstructure

We report the effects of a high power light beam on the performance of a self electro-optic effect device, which employs an extremely shallow quantum well in an asymmetric Fabry-Perot etalon structure. For a continuously incident laser beam having 4 mW power and 7 μm diameter, for example, we observed the change of reflectivity difference from 25% to 13% and the change of contrast ratio from 16 to 5, both of which we attribute to the rise of local temperature induced by laser heating. Experimental measurements and a simplified thermal analysis show that the device degradation by ohmic heating at reverse bias of -5 V is more pronounced than that by the exciton absorption saturation at forward bias     

Near room-temperature continuous-wave operation of all-monolithic InAlGaAs/InP 1.3 /spl mu/m VCSELs

InAlGaAs/InP-based all-monolithic 1.3 /spl mu/m VCSELs operating continuous wave up to 18/spl deg/C are demonstrated. The whole structure is grown by a single step of MOCVD. Selective wet etching of an InP layer is used to form an air-gap aperture for the current confinement. The threshold current of an 8 /spl mu/m device at 15/spl deg/C is /spl sim/2.8 mA.     

Replication of microlens arrays by injection molding

Injection molding could be used as a mass production technology for microlens arrays. It is of importance, and thus of our concern in the present study, to understand the injection molding processing condition effects on the replicability of microlens array profile. Extensive experiments were performed by varying processing conditions such as flow rate, packing pressure and packing time for three different polymeric materials (PS, PMMA and PC). The nickel mold insert of microlens arrays was made by electroplating a microstructure master fabricated by a modified LIGA process. Effects of processing conditions on the replicability were investigated with the help of the surface profile measurements. Experimental results showed that a packing pressure and a flow rate significantly affects a final surface profile of the injection molded product. Atomic force microscope measurement indicated that the averaged surface roughness value of injection molded microlens arrays is smaller than that of mold insert and is comparable with that of fine optical components in practical use.This paper was presented at the Fifth International Workshop on High Aspect Ratio Microstructure Technology HARMST 2003 in June 2003.The authors would like to thank Korean Ministry of Science and Technology for the financial supports via the National Research Laboratory Program (2000-N-NL-01-C-148) and RAYGEN Co., Ltd. for the technical help in using the 3D profile measuring system.