Physical modeling of urban air-pollutant transport

Air-pollutant transport within an urban setting is conditioned by local urban geometry, urban-modified meteorological variables, a wide variety of source characteristics and local topography. Extreme complexity and local specificity of the resulting dispersion process requires the use of physical modeling rather than numerical or analytical methods to predict concentration distributions. Serving as an analog computer the boundary-layer wind tunnel provides reliable concentration data which can be applied directly to design and/or decision making.A brief review is made of similarity criteria for simulating physical modeling of the atmospheric boundary-layer and source characteristics in a boundary-layer wind tunnel. Applications to several problems related to stack, vent and automobile emissions are described. Rudimentary portions of a data bank are presented which, with additional data acquisition, can provide a practical method for prediction of automobile exhaust concentrations that will result from proposed freeways or alternative traffic routings.     

A sub-2.0 V BiCMOS logic circuit with a BiCMOS charge pump

A BiCMOS logic circuit with very small input capacitance has been developed, which operates at low supply voltages. A High-beta BiCMOS (Hβ-BiCMOS) gate circuit which fully utilizes the bipolar transistor features achieves 10 times the speed of a CMOS gate circuit with the same input capacitance and operating at 3.3 V supply voltage. In order to lower the minimum supply voltage of Hβ-BiCMOS, a BiCMOS circuit configuration using a charge pump to pull up the output high level of the BiCMOS gate circuit is proposed. By introducing a BiCMOS charge pump, Hβ-BiCMOS achieves very high speed operation at sub-2.0 V supply voltage. It has also been demonstrated that only a very small number of charge pump circuits are required to drive a large number of Hβ-BiCMOS gate circuits     

Inhibition by dexamethasone of human neutrophil apoptosis in vitro

The efficacy of collagen-sponge to reduce postoperative scar formation was investigated in 65 Japanese white rabbits that received laminectomy in the 7th and 8th thoracic vertebra. The defect after laminectomy was filled by collagen-sponge in 25 rabbits, by free fat in 20 rabbits, and by nothing in 20 rabbits as controls. The animals were sacrificed 2, 4, 8 and 12 weeks and additional 5 rabbits of which defects were filled with collagen-sponge were sacrificed after 24 weeks. All the defects were examined histologically. At 4 weeks after laminectomy, the defects filled by collagen-sponge showed that fibrous tissue had invaded into the sponge, but there was no remarkable adhesion to the dura mater. At 8 weeks, the defect with collagen sponge showed foaming cells, and no thickening of the dura mater was observed. At 12 weeks, the grouping of foaming cells was partially replaced by fat cells. At 24 weeks, most of the foaming cells were replaced by fat cells, and the defect was then similar to that filled by free fat at 12 weeks. In contrast, the defect with no interposed membrane was already filled with fibrous tissue at 4 weeks, and adhesion to the dura mater was observed. Although the free-fat graft at 12 weeks postoperatively showed no remarkable adhesion around the dura mater, infiltration of fat tissue into the spinal canal was observed in 2 of 5 rabbits. These results indicated that collagen-sponge can be utilized as a new biomaterial to effectively prevent scar formation after laminectomy.     

Regulation of Neutrophil Functions by Hv1/VSOP Voltage-Gated Proton Channels

The voltage-gated proton channel, Hv1, also termed VSOP, was discovered in 2006. It has long been suggested that proton transport through voltage-gated proton channels regulate reactive oxygen species (ROS) production in phagocytes by counteracting the charge imbalance caused by the activation of NADPH oxidase. Discovery of Hv1/VSOP not only confirmed this process in phagocytes, but also led to the elucidation of novel functions in phagocytes. The compensation of charge by Hv1/VSOP sustains ROS production and is also crucial for promoting Ca²⁺ influx at the plasma membrane. In addition, proton extrusion into neutrophil phagosomes by Hv1/VSOP is necessary to maintain neutral phagosomal pH for the effective killing of bacteria. Contrary to the function of Hv1/VSOP as a positive regulator for ROS generation, it has been revealed that Hv1/VSOP also acts to inhibit ROS production in neutrophils. Hv1/VSOP inhibits hypochlorous acid production by regulating degranulation, leading to reduced inflammation upon fungal infection, and suppresses the activation of extracellular signal-regulated kinase (ERK) signaling by inhibiting ROS production. Thus, Hv1/VSOP is a two-way player regulating ROS production. Here, we review the functions of Hv1/VSOP in neutrophils and discuss future perspectives.     

Screening of Inhibitors Targeting Heat Shock Protein 47 Involved in the Development of Idiopathic Pulmonary Fibrosis

Heat shock protein 47 (HSP47), a collagen-specific molecular chaperone, is causally related to fibrotic diseases, including idiopathic pulmonary fibrosis. The identification of Compounds that interfere with the HSP47-collagen interaction is essential for the development of relevant therapeutics. Herein, we prepared human HSP47 as a soluble fusion protein expressed in E. coli and established an assay system for HSP47 inhibitor screening. We screened a natural and synthetic Compound library established at Nagasaki University. Among 1023 Compounds, 13 exhibited inhibitory activity against human HSP47, of which three inhibited its function in a dose-dependent manner. Epigallocatechin-3-O-gallate, one of these three Compounds, is a typical polyphenol Compound derived from tea leaves. Structurally related Compounds were synthesized and examined for their activity, revealing a hydroxyl group at A-ring position 5 as important for its activity. The present findings provide valuable insight for the development of natural product-derived therapeutics for fibrotic diseases, including idiopathic pulmonary fibrosis.     

An Engineered Biliverdin-Compatible Cyanobacteriochrome Enables a Unique Ultrafast Reversible Photoswitching Pathway

Cyanobacteriochromes (CBCRs) are promising optogenetic tools for their diverse absorption properties with a single compact cofactor-binding domain. We previously uncovered the ultrafast reversible photoswitching dynamics of a red/green photoreceptor AnPixJg2, which binds phycocyanobilin (PCB) that is unavailable in mammalian cells. Biliverdin (BV) is a mammalian cofactor with a similar structure to PCB but exhibits redder absorption. To improve the AnPixJg2 feasibility in mammalian applications, AnPixJg2_BV4 with only four mutations has been engineered to incorporate BV. Herein, we implemented femtosecond transient absorption (fs-TA) and ground state femtosecond stimulated Raman spectroscopy (GS-FSRS) to uncover transient electronic dynamics on molecular time scales and key structural motions responsible for the photoconversion of AnPixJg2_BV4 with PCB (Bpcb) and BV (Bbv) cofactors in comparison with the parent AnPixJg2 (Apcb). Bpcb adopts the same photoconversion scheme as Apcb, while BV4 mutations create a less bulky environment around the cofactor D ring that promotes a faster twist. The engineered Bbv employs a reversible clockwise/counterclockwise photoswitching that requires a two-step twist on ~5 and 35 picosecond (ps) time scales. The primary forward P_fr → P_o transition displays equal amplitude weights between the two processes before reaching a conical intersection. In contrast, the primary reverse P_o → P_fr transition shows a 2:1 weight ratio of the ~35 ps over 5 ps component, implying notable changes to the D-ring-twisting pathway. Moreover, we performed pre-resonance GS-FSRS and quantum calculations to identify the Bbv vibrational marker bands at ~659,797, and 1225 cm⁻¹. These modes reveal a stronger H-bonding network around the BV cofactor A ring with BV4 mutations, corroborating the D-ring-dominant reversible photoswitching pathway in the excited state. Implementation of BV4 mutations in other PCB-binding GAF domains like AnPixJg4, AM1_1870g3, and NpF2164g5 could promote similar efficient reversible photoswitching for more directional bioimaging and optogenetic applications, and inspire other bioengineering advances.     

Analysis of Reusability using ‘Marginal Reuse Rate’

While reuse is an effective lifecycle option in terms of reduction of environmental loads and value of reutilization, reuse has inherent difficulties. Our naive question is why component reuse of home appliances seems impossible while that of photocopiers succeeded. This paper clarifies an essential factor for successful reuse; that is, the balance between supply and demand of reusables, and proposes an index named ‘marginal reuse rate,’ which indicates upper limit of reusability. By using this index, reusability of several products is analyzed. The marginal reuse rate indicates that design of lifecycle, in addition to product design, is indispensable for successful reuse.     

Removal of nitrogen oxides from air by chemicals-impregnated carbons

Fixation of nitrogen oxides (NO_x) in air onto granular activated carbon impregnated with chemicals was attempted to improve removal efficiency of NO_x by activated carbon adsorption. Nitric oxide (NO) and nitrogen dioxide (NO₂), were tried to remove by a flow test. Fixed-bed adsorption breakthrough curves were obtained when some kinds of carbon were used. The amount adsorbed of NO₂ changed with the amount and kinds of metallic salts impregnated. Chemicals-impregnated carbons were prepared from a commercial activated carbon. Among obtained carbons, the one which showed the highest selectivity for NO_x was chosen, and its performance with the change in humidity was determined. Removal mechanism of NO₂ was estimated, and the carbon impregnated with potassium hydroxide was found to be superior to any other carbon tested. The amount of the adsorbed NO and that produced by the reduction of NO₂ were determined from the breakthrough curves.     

Different feeding and gustatory responses to ecdysone and 20-hydroxyecdysone by larvae of the silkworm,Bombyx mori

The feeding and gustatory responses to ecdysone and 20-hydroxyecdysone were investigated in the silkworm,Bombyx mori. 20-Hydroxyecdysone reduced feeding response strongly in fourth- and fifth-instar larvae, whereas ecdysone had no effect on feeding response. 20-Hydroxyecdysone stimulated the R receptor, the receptor to feeding deterrents, to a great degree. By contrast, ecdysone was much less effective for stimulating the R receptor. These results indicate that ecdysone and 20-hydroxyecdysone have different effects on feeding response due to different interactions with mouthpart chemoreceptors.