Design and fabrication of a significantly shortened multimode interference coupler for polarization splitter application

We report that we have successfully designed and fabricated a significantly shortened multimode interference coupler for application in polarization splitter, using a phenomenon that we termed "quasi-state" (QS) imaging effect. First, we identified and analyzed the QS imaging effect, and, based on the QS analysis, designed and fabricated a novel multimode interference (MMI) device with its split length shortened to 1/5 of a normally designed MMI split length. The fabrication is simple and cost effective and the fabricated device shows outstanding characteristics in extinction ratio, signal homogeneity, excess loss, and tolerance in the length of the splitter.     

Whole-body [18F]FDG PET in the management of metastatic brain tumours

BACKGROUND: To determine its roles in the diagnosis and the systemic evaluation of metastatic brain tumours, whole-body positron emission tomography (PET) using [18F]FDG was performed in 20 consecutive patients. METHODS: All patients were thought to be suffering or needing to be differentiated from metastatic brain tumours. Nine patients had multiple brain lesions; six were older and showed a rim-enhancing lesion with surrounding oedema; seven had homogeneously enhancing periventricular lesion(s) on computed tomography (CT) and/or magnetic resonance (MR) imaging, thought to be central nervous system lymphomas. Two patients had skull mass(es) and two patients had a solid mass suspected to be, respectively, a haemorrhagic metastasis and a metastatic malignant melanoma. All of them received whole-body [18F]FDG PET and conventional systemic work-up for metastasis in order to compare the results of the two methods. RESULTS: Metastatic brain tumours were diagnosed on whole-body [18F]FDG PET in eleven patients who had extracranial and intracranial hypermetabolic lesions. In nine of these, a conventional work-up also detected primary lesions which on whole-body [18F]FDG PET were seen to be hypermetabolic foci. Systemic lymph node metastases were detected by whole-body [18F]FDG PET only in two patients and histological diagnosis was possible by biopsy of lymph nodes rather than of brain lesions. In the remaining nine patients who had only intracranial hypermetabolic foci, histological diagnosis was made by craniotomy or stereotactic biopsy. It was confirmed that seven of nine patients were suffering from a primary brain tumour and two from metastatic carcinoma. None of the nine showed evidence of systemic cancer on conventional work-up. Histological diagnoses of the primary brain tumours were four cases of primary central nervous system lymphoma and one each of multifocal glioblastoma, Ewing's sarcoma, and cavernous angioma. Patients felt no discomfort during the whole-body [18F]FDG PET procedure and there were no complications. The false negative rate in [18F]FDG PET and in conventional work-up was 15.4% and 30.7% respectively. There were no false positives on either [18F]FDG PET or conventional work-up. CONCLUSION: It is suggested that whole-body [18F]FDG PET is a safe, reliable, and convenient method for the diagnosis and systemic evaluation of patients thought to be suffering or needing to be differentiated from a metastatic brain tumour.     

固态薄膜可重编程的模拟可变电阻存储器的制造和性能

介绍氧化钨基永久性的电可重编程的可变电阻器作为用于电子神经网络的模拟突触记忆联接器。该器件具有类晶体管的多层薄膜器件结构，它是依次由直流溅射和电子束蒸发工艺沉积到一个绝缘衬底，即衬底／Ni／WO3／SiO／Cr2O3／SiO／Al。用电压控制H 离子可逆地内插和去插到WO3薄膜来调制电阻。一个吸湿的Cr2O3薄膜用作H 离子源。该器件电阻可以特制和稳定在很宽的动态范围（约105～109Ω），并且编程速度受控制电压调制。讨论了该器件在响应速度、可逆性、稳定性和循环性方面的适应能力。     

Contribution of single-unit spike waveform changes to temperature-induced alterations in hippocampal population spikes

Brain temperature changes accompany exploratory behavior and profoundly affect field potential amplitudes recorded in hippocampus. The waveform alterations in fascia dentata include a reduction in population spike area, which might be explained by fewer granule cells firing in response to a given stimulus or by an alteration in the size or shape of the individual action potentials. This study was designed to assess these alternate possibilities. In experiment 1, changes in the shape and firing rates of single cells recorded in the fascia dentata of awake rats were compared with changes in the population spike before and after a bout of activity. Single-unit amplitudes were significantly reduced following exploration, and there was a small (< 3%) change in unit spike-width. These changes, however, were insufficient to account, in a linear fashion, for the entire decline in the population spike. In experiment 2, radiant heat was used to manipulate brain temperature in anesthetized rats. As in the first experiment, the magnitude of change in the extracellular units was much smaller than the change in population spike amplitude. The spontaneous firing rates of the cells were also modified by brain temperature changes. In experiment 3, the polysynaptic, contralateral commissural response (which covaries with changes in the ipsilateral population spike at a fixed temperature) was measured as a function of either exploratory behavior or radiant heat. The relationship between the ipsilateral population spike and corresponding polysynaptic commissural response was altered following exploration and passive warming in a manner consistent with a reduction in net granule cell output, reduced transmission efficacy through the polysynaptic circuit, or a combination of these. Taken together these data suggest that at least two factors contribute to temperature-dependent changes in the perforant path-evoked population spikes recorded in the fascia dentata: changes in the size of individual action potentials and alterations in discharge of action potentials in response to a given stimulus.     

Analysis of platelet adhesion to a collagen-coated surface under flow conditions: the involvement of glycoprotein VI in the platelet adhesion

Platelet adhesion to the exposed surface of the extracellular matrix in flowing blood is the first and critical reaction for in vivo thrombus formation. However, the mechanism of this in vivo platelet adhesion has yet to be studied extensively. One of the reasons for this is the lack of a practical assay method for assessing platelet adhesion under flow conditions. We have devised an assay method (the fluorescent adhesion assay) that is based on the technique originally reported by Hubbell and McIntire (Biomaterials 7:354, 1986) with some modifications to make it more amenable for assaying small samples and have developed an analysis method to quantify the extent of platelet adhesion and aggregation from fluorescence images by using a computer-assisted image analysis system. In our assay, platelet adhesion, expressed as the percentage of the area covered by adhered platelets, was found to increase biphasically as a function of time. In the first phase, platelets interacted with the coated collagen, transiently stopping on the surface; we called this reaction the temporary arrest. In the second phase, platelets adhered much more rapidly and permanently on the surface, and this adhesion was dependent on the shear rate; platelets formed aggregates in this phase. We used our assay to analyze the effects of platelet aggregation inhibitors on platelet adhesion. All three examined inhibitors, EDTA (10 mmol/L), antiglycoprotein (GP) IIb/IIIa, and GRGDS peptide (1 mmol/L), inhibited the second phase adhesion in flowing blood. Furthermore, GPVI-deficient platelets also showed defective second-phase adhesion under the same conditions. These results suggested that GPIIb/IIIa activation and GPVI contribute to the reaction inducing the second phase. The second-phase adhesion has been extensively investigated, and the consensus is that this reaction is mainly attributable to the platelet-platelet interaction. In this report, we were able to detect an earlier reaction, the temporary arrest. This temporary arrest would reflect the fast and weak interaction between platelet GPIb/IX and collagen-von Willebrand factor complexes on the collagen-coated surface.     

Simultaneous refining of phosphorus and sulfur from hot metal utilizing recycled sinter ore dust

An experimental study is carried out to determine the possibility of utilizing the recycled sinter ore dust for refinging flux for hot metal. The dust has good physical and chemical properties as an injection powder, however, it contains masses of about 0.24% S and a substantial amount of sulfur which can be picked up by the hot metal during the injection treatment. Therefore, sinter ore dust is mixed with burnt lime, fluorspar and sodium carbonate to increase the sulfide capacity of the flux. The fluxes are tested for hot metal dephosphorization and desulfurization in laboratory and plant scale experiments. The fluxes show an excellent dephosphorization efficiency without sulfur pick up. In case of the flux containing sodium carbonate masses of 10%, sulfur in hot metal is simultaneously removed. In addition, a higher manganese yield in hot metal is obtained in case of a sodium carbonate containing flux at the end of injection treatment.     

Plasma chemistries for dry etching of NiFe and NiFeCo

Plasma chemistries based on chlorine, bromine, or iodine have been investigated for inductively coupled plasma etching of NiFe and NiFeCo. There is clear evidence of a chemically enhanced etch mechanism with both Cl₂- and I₂- based mixtures, with no enhancement present for Br₂ chemistries. Etch yields are typically low (≤0.25), emphasizing the need for high ion fluxes in order to achieve practical material removal rates.     

Polypropylene alloy filaments dyeable with disperse dyes

Polypropylene fibres which can be conventionally dyeable using disperse dyes have been prepared by alloying with nylon 6 and a polypropylene grafted maleic anhydride compatibiliser during extrusion. The dyeing performance of fibres containing various amounts of these components has been assessed.     

The current injection method for AC plasma display panel (PDP) sustainer

A new concept of energy recovery for a plasma display panel (PDP) is proposed. Different from conventional LC resonant sustaining drivers, the current built up before inverting the polarity of the panel electrodes is utilized to change the panel polarity together with energy previously charged in panel capacitance. This operation provides zero-voltage switching of switches and reduction of electromagnetic interference by rejecting the surge current when the sustain switches are turned on. The buildup current helps to reduce the transition time of the panel polarity and may produce more stable light waveforms. This method is suitable for a PDP sustaining driver requiring stable light emission characteristic while it maintains low circuit loss like the series-resonant-type energy recovery circuit which is known to be a very effective method.