Adhesion control of fungal spores on solid surfaces using hydrophilic nanoparticles

Mold growth can trigger a variety of serious problems such as allergies and asthma. Designing surfaces that are unfavorable for the adhesion of fungal spores is considered an effective method to prevent fungal growth. In this study, the effect of hydrophilic surface treatment on the adhesion of fungal spores onto substrates was investigated using Aspergillus oryzae as a model fungus. The fungal spores that strongly adhered on the hydrophilic substrates under atmospheric conditions were easily removed by lightly washing by hand in water. These experimental results agreed well with thermodynamic predictions based on contact angle measurements. In addition, the removal ratio of the fungal spores on substrates coated with silica nanoparticles was higher than that on plasma-treated glass. It is believed that the contact area between a spore and substrate depended on the substrate roughness. Atomic force microscopy revealed that there was almost no adhesive force between the spores and glass substrate coated with silica nanoparticles. These results suggest that hydrophilic treatment using hydrophilic silica nanoparticles is more effective than hydrophilic plasma treatment to prevent fungal spore adhesion on glass substrates.     

Experimental studies of fault location in PV module strings

Two methods for the fault location in PV module string were experimentally studied. One was the earth capacitance measurement (ECM) and the other was the time-domain reflectometry (TDR). By ECM, the disconnection position in the string was estimated by the earth capacitance value without the effects of the irradiance change, and the estimation error was small enough to determine the disconnection position in actual repair/maintenance operation. On the other hand, TDR could detect the degradation (series resistance increase) and the positions in the string by the change of response waveform.     

THz-Wave Spectroscopy Applied to the Detection of Illicit Drugs in Mail

A series of experiments in the field of THz-wave spectroscopy is described. The measurement of absorption spectra of solid samples, powders, and liquids is demonstrated using various optical setups. One of the sources we used is a widely tunable coherent THz-wave generator relying on an optical parametric process: nanosecond Q-switched Nd : YAG laser light scattering from the polariton mode of a MgO-doped LiNbO₃ crystal. For the measurement of the absorption of THz waves in liquids, a train of waves is allowed to oscillate inside a silicon prism. A liquid placed on a total internal reflection surface lowers the quality factor of the resonator, which allows determining the complex refraction index of the sample by frequency scanning. We have also developed a technique for THz chemical imaging, by introducing the component spatial pattern analysis. The spatial distribution of the chemicals, such as illicit drugs concealed in an envelope, is obtained from terahertz multispectral transillumination images and absorption spectra. To compensate for the low imaging speed, a prescreening step is proposed, by first detecting the presence of powders in the envelopes, which is achieved by measuring in real time the amount of scattering produced by the envelopes. Details and examples are provided.     

Removal properties of low-thermal-expansion materials with rotating-sphere elastic emission machining

Optical mirrors used in extreme ultraviolet lithography systems require a figure accuracy and a roughness of about 0.1 nm rms. In addition, mirror substrates must be low-thermal-expansion materials. Thus, in this study, we processed two low-thermal-expansion materials, ULE [K. Hrdina, B. Hanson, P. Fenn, R. Sabia, Proc. SPIE 4688 (2002) 454.] (Corning Inc.) and Zerodur [I. Mitra, M.J. Davis, J. Alkemper, Rolf Müller, H. Kohlmann, L. Aschke, E. Mörsen, S. Ritter, H. Hack, W. Pannhorst, Proc. SPIE 4688 (2002) 462.] (SCHOTT AG), with elastic emission machining (EEM) in order to evaluate the removal properties. Consequently, we successfully calculated the respective removal rates, because removal volumes were found to be proportional to process times in EEM. Moreover, we demonstrated that the surface roughness of Zerodur is reduced to 0.1 nm rms in the spatial wavelength range from 100 μm to 1 mm.     

Chemokine-like Receptor 1 in Brain of Spontaneously Hypertensive Rats Mediates Systemic Hypertension

Adipocytokine chemerin is a biologically active molecule secreted from adipose tissue. Chemerin elicits a variety of functions via chemokine-like receptor 1 (CMKLR1). The cardiovascular center in brain that regulates blood pressure (BP) is involved in pathophysiology of systemic hypertension. Thus, we explored the roles of brain chemerin/CMKLR1 on regulation of BP in spontaneously hypertensive rats (SHR). For this aim, we examined effects of intracerebroventricular (i.c.v.) injection of CMKLR1 small interfering (si)RNA on both systemic BP as measured by tail cuff system and protein expression in paraventricular nucleus (PVN) of SHR as determined by Western blotting. We also examined both central and peripheral protein expression of chemerin by Western blotting. Systolic BP of SHR but not normotensive Wistar Kyoto rats (WKY) was decreased by CMKLR1 siRNA. The decrease of BP by CMKLR1 siRNA persisted for 3 days. Protein expression of CMKLR1 in PVN of SHR tended to be increased compared with WKY, which was suppressed by CMKLR1 siRNA. Protein expression of chemerin in brain, peripheral plasma, and adipose tissue was not different between WKY and SHR. In summary, we for the first time revealed that the increased protein expression of CMKLR1 in PVN is at least partly responsible for systemic hypertension in SHR.     

Cardiovascular Characteristics of Zucker Fatty Diabetes Mellitus Rats,an Animal Model for Obesity and Type 2 Diabetes

Zucker fatty diabetes mellitus (ZFDM) rats harboring the missense mutation (fa) in a leptin receptor gene have been recently established as a novel animal model of obesity and type 2 diabetes (T2D). Here, we explored changes in cardiovascular dynamics including blood pressure and heart rate (HR) associated with the progression of obesity and T2D, as well as pathological changes in adipose tissue and kidney. There was no significant difference in systolic blood pressure (SBP) in ZFDM-Lepr^fa/fa (Homo) compared with ZFDM-Lepr^fa/+ (Hetero) rats, while HR and plasma adrenaline in Homo were significantly lower than Hetero. The mRNA expression of monocyte chemotactic protein-1 in perirenal white adipose tissue (WAT) from Homo was significantly higher than Hetero. Interscapular brown adipose tissue (BAT) in Homo was degenerated and whitened. The plasma blood urea nitrogen in Homo was significantly higher than Hetero. In summary, we demonstrated for the first time that HR and plasma adrenaline concentration but not SBP in Homo decrease with obesity and T2D. In addition, inflammation occurs in WAT from Homo, while whitening occurs in BAT. Further, renal function is impaired in Homo. In the future, ZFDM rats will be useful for investigating metabolic changes associated with the progression of obesity and T2D.     

Single-shot microscopic electron imaging of intense femtosecond laser-produced plasmas

A simple technique for single-shot microscopic electron imaging was demonstrated for the study of intense femtosecond laser-produced plasmas. Passed through a permanent magnet lens designed for 110-keV electrons, hot electrons emitted from the plasma produced by a single laser pulse of 0.8 mJ with intensity of 3 × 10(16) W/cm(2) were successfully imaged. Analyzing this image, we found that electrons were emitted from an area of 3 μm in diameter. At higher laser intensity of 10(18) W/cm(2), distinct structures were observed in and near the focal spot of the laser; that is, the electrons were emitted from several separate spots. These results show that laser-plasma electron imaging is promising for studying the interactions of femtosecond lasers with high-density plasmas.     

Direct Synthesis of N‐Acyl‐N,O‐hemiacetals via Nucleophilic Addition of Unactivated Amides and Their O‐Acetylation: Access to α,α‐Difunctionalized N‐Acylimines

A mild, metal‐free synthesis of polyfunctionalized N‐acyl‐N,O‐hemiacetals was developed via the nucleophilic addition of unactivated amides to ketones. The protocol demonstrated a wide substrate scope, with good isolated yields. Additionally, their O‐acetylated products serve as a precursor of α,α‐difunctionalized N‐acylimines. An addition reaction of broad scope of nucleophiles to generate N‐acylimines is also reported.

     

Ultrasound navigation based on minimally designed vehicle inspired by the bio-sonar strategy of bats

ABSTRACT

In this study, we conducted vehicle experiments and a numerical simulation based on a simple algorithm inspired by the bio-sonar system of bats to investigate how the behavioral strategy employed by bats contributes to acoustic navigation for minimal-design sensing. In particular, a double-pulse scanning method inspired from the echolocation behavior of bats was proposed, in which (1) the direction of ultrasound emission by a vehicle equipped with 1 transmitter and 2 receivers was alternately shifted between the movement direction of the vehicle and the direction of the nearest obstacle, and (2) the movement direction of the vehicle was calculated for every double-pulse emission based on integrated information from all echoes detected. As a result of 100 repeated drives in a practical course, the success rate of an obstacle-avoidance drive improved from 13% with the conventional single-pulse scanning method to 73% with the proposed method. Furthermore, the numerical simulation demonstrated that the proposed method achieves robust path planning by suppressing the localization ambiguity due to the interference of multiple echoes. The practical experiments and numerical simulation suggest that bats employ a simple behavioral solution in the operation of acoustic sensing for various problems occurring in the real world.     

The Need of Terahertz Cameras for Standardizing Sensitivity Measurements

The applicability of a blackbody source to sensitivity measurements and calibration of an uncooled Terahertz (THz) focal plane array (FPA) is discussed, but the combination of a blackbody source and a band-pass filter may not be suitable for these purposes. Two ways to measure the minimum detectable power (MDP) of uncooled THz-FPAs are described and compared when used with strong THz sources such as a quantum cascade laser (QCL). The MDP is defined as the radiant power that produces a signal-to-noise ratio of unity in the output of a THz imager that uses a THz-FPA operating at a TV frame rate. One method (method 1) is based on the hypothesis that the beam pattern of the THz source is close to a Gaussian pattern. In another method (method 2), the signal level of the background in an image that does not contain a THz source is subtracted from the signal of the image. While method 2 is more flexible, how large the signals coming from THz source should be, as compared with the noise level, remains to be defined. Finally, based on issues with the current non-uniformity correction (NUC) technique, specifications are proposed for THz source power and wobbling technique to obtain uniform illumination for an ideal NUC technique.