Moderately Oxidizing Thioxanthylium Organophotoredox Catalysts for Radical-Cation Diels-Alder Reactions.

Moderately oxidizing thioxanthylium photoredox catalysts that operate under irradiation with green light have been developed. These catalysts exhibit relatively moderate excited-state reduction potentials [E1/2(C*/C•-) = 1.75-1.94 V vs saturated calomel electrode (SCE)] and can efficiently promote radical-cation Diels-Alder reactions under irradiation with green light. Interestingly, ß-halogenostyrenes (Ep/2 = 1.57-1.61 V vs SCE) are well tolerated, affording synthetically useful halocyclohexenes.

Visible-light-induced [4 + 2] cycloaddition of pentafulvenes by organic photoredox catalysis.

We have developed thioxanthylium photoredox catalyzed [4 + 2] cycloaddition of pentafulvenes at room temperature under green light irradiation, which affords tetrahydrocyclopenta[b]chromenes with high regioselectivities. The present reaction provides a sustainable approach to carry out the cycloaddition of pentafulvenes without the use of transition metal catalysts or high-temperature conditions. This procedure enables a mild and straightforward access to 1,3a,9,9a-tetrahydrocyclopenta[b]chromenes. The quantum yield of the reaction (Φ = 0.15) indicates that the reaction would mainly proceed via photocatalytic pathways.

Organophotoredox-Catalyzed Intermolecular Oxa-[4+2] Cycloaddition Reactions.

An intermolecular oxa-[4+2] cycloaddition reaction promoted by a thioxanthylium photoredox catalyst under irradiation with green light has been developed. The reaction of ortho-quinone methides with styrenes smoothly affords the desired cycloadducts. Especially styrenes bearing electron-donating groups are efficiently transformed in this reaction. This method represents a sustainable way to carry out oxa-[4+2] cycloaddition reactions using only a catalytic amount of a photocatalyst and visible light.

Access to Electron-Deficient 2,2-Disubstituted Chromanes: A Highly Regioselective One-Pot Synthesis via an Inverse-Electron-Demand [4 + 2] Cycloaddition of ortho-Quinone Methides.

We report the one-pot synthesis of 2,2-disubstituted chromanes with electron-withdrawing substituents. This reaction provides a simple yet efficient route to a wide range of electron-deficient chromanes in high yield and excellent regioselectivity. The reaction of salicylaldehyde with 1,1-disubstituted ethylenes smoothly furnishes these electron-deficient chromanes, which can be further transformed into functionalized chromanes or chromene. For example, BW683C was effectively synthesized from 5-chlorosalicylaldehyde with 4-chlorostyrene in two steps in excellent yield. The present reaction thus provides versatile access to functionalized electron-deficient chromanes and chromenes and therefore constitutes a promising tool for the synthesis of biologically and photochemically active molecules.

Morphological characteristics of male and female hypopharynx: A magnetic resonance imaging-based study.

Studies with three-dimensional (3D) vocal tract visualization using magnetic resonance imaging (MRI) have suggested that hypopharyngeal cavities, i.e., laryngeal cavity and bilateral piriform fossa, may be the acoustic loci to express speaker characteristics in male speech sounds. Previous studies mainly investigated the hypopharynx in males but few for females. This study explored the hypopharynx morphological characteristics for the subjects in both genders by MRI. 3D numerical vocal tracts at vowels were reconstructed from the MRI datasets of three male and four female Chinese subjects. Geometrical measurements were conducted for the hypopharyngeal cavities. Morphological observations and statistical analyses revealed both commonalities and differences between the male and female subjects. The laryngeal cavity shapes in females were found similar to males resembling a Helmholtz resonator rather than a simple straight closed tube, and the bilateral piriform fossa cavities showed an asymmetry: the right is longer and wider than the left in both genders. As for the cavity size across vowels, for both the male and female subjects the laryngeal cavity and piriform fossa in /i/ were observed larger than those in /a/. To summarize gender characteristics, the female subjects were characterized by the smaller laryngeal cavity and piriform fossa compared with males.

Friedel-Crafts approach to the one-pot synthesis of methoxy-substituted thioxanthylium salts.

An efficient synthesis of methoxy-substituted thioxanthylium salts has been developed. The reaction of diaryl sulfides with benzoyl chlorides in the presence of TfOH smoothly proceeded to give the desired thioxanthylium salts in good yields. In their UV-vis spectra, the maximum absorption wavelengths of methoxy-functionalized thioxanthylium salts were observed at around 460 nm, which show a drastic red shift compared to the parent thioxanthylium salts. The present reaction provides a versatile access to functionalized thioxanthylium salts, and therefore it constitutes a promising tool for the synthesis of biologically and photochemically active molecules.

The Mechanism and Representation of Korean Three-Way Phonation Contrast: External Photoglottography, Intra-Oral Air Pressure, Airflow, and Acoustic Data.

This paper aims to refine our understanding of the speech mechanism and laryngeal features involved in the Korean lenis (/p t k/), aspirated (/ph th kh/), and fortis (/p' t' k'/) plosives. For this purpose we made measurements using a new noninvasive technique called external lighting and sensing photoglottography (ePGG) as well as intra-oral air pressure (Pio) above the glottis, airflow, and acoustic data. From simultaneous recordings of the experimental data, we were ableto quantify the laryngeal-oral coordination of glottal opening and a consonant release, and the covariance of airflow peak and duration of aspiration with glottal opening. The phasing of glottal opening and the 3-way phonation contrast occurs in the order, from early to late, fortis, lenis < aspirated plosives, and the glottal opening peak ranges from low to high in the same order. We also found that a Pio peak, the durations of a high Pio plateau and an oral closure, and F0 are independent of the glottal opening mechanism, varying in the order lenis < aspirated and fortis plosives. From these findings, we propose that the 2 independent patterns are accounted for by the articulator-based features [±spread glottis] and [±tense], respectively.

A base-mediated self-propagative Lossen rearrangement of hydroxamic acids for the efficient and facile synthesis of aromatic and aliphatic primary amines.

A variety of aromatic and aliphatic hydroxamic acids were converted to the corresponding primary amines via base-mediated rearrangement. This rearrangement could proceed with less than 1 equiv. of K2CO3 in polar solvents under thermal conditions with no external reagents. This rearrangement has several features including no external activating agents needed for promoting the rearrangement, less than one equivalent of a base is sufficient for the reaction, and a clean reaction in which only carbon dioxide is produced as a by-product. A self-propagating mechanism via an isocyanate intermediate is proposed and elementary reaction steps, namely, chain propagation reactions are supported by experiments.

A study on transvelar coupling for non-nasalized sounds.

Previous studies have found that the velum in speech production may not only serve as a binary switch with on-off states for nasal and non-nasal sounds, but also partially alter the acoustic characteristics of non-nasalized sounds. The present study investigated the unique functions of the velum in the production of non-nasalized sounds by using morphological, mechanical, and acoustical measurements. Magnetic resonance imaging movies obtained from three Japanese speakers were used to measure the behaviors of the velum and dynamic changes in the pseudo-volume of the pharyngeal cavity during utterances of voiced stops and vowels. The measurements revealed no significant enlargements in the supraglottal cavity as subjects uttered voiced stops. It is found that the velum thickness varied across utterances in a way that depended on vowels, but not on consonants. The mechanical and acoustical observations in the study suggested that the velum is actively controlled to augment the voice bars of voiced stops, and nostril-radiated sound is one of the most important sources for voice bars, just as is laryngeal wall vibration. This study also proposed a two-layer diaphragm model that simulates transvelar coupling during the production of non-nasalized speech sounds. The simulation demonstrated that the model accurately represented the basic velar functions involved in speech production.

Near-infrared photoglottography for measuring multiple glottal events.

Near-infrared (NIR) photoglottography (PGG) is a non-invasive method for monitoring glottal activities which retains functionality of conventional PGG using visible light with more convenient accessibility. This paper is to investigate its performance in comparison with simultaneously recorded electroglottography (EGG) signals. Results showed that NIR PGG detects continuous transillumination for glottal aperture and vocal-fold contact. Glottal timing markers known as glottal closure and opening instants are detectable agreeing to the corresponding EGG-based instants. Further, it was inferred that variations of glottal waveforms based on NIR PGG reflect vertical vocal-fold edge motions.

Redox Potential Controlled Selective Oxidation of Styrenes for Regio- and Stereoselective Crossed Intermolecular [2 + 2] Cycloaddition via Organophotoredox Catalysis.

A redox potential controlled intermolecular [2 + 2] cross-cycloaddition has been developed in the presence of a thioxanthylium photoredox catalyst. Electron-rich styrenes such as ß-bromostyrene (Ep/2 = +1.61 V vs SCE) were selectively oxidized by a thioxanthylium photoredox catalyst (E1/2 (C*/C•-) = +1.76 V vs SCE) to styryl radical cations and reacted with styrene (Ep/2 = +1.97 V vs SCE) to furnish polysubstituted cyclobutanes in high yields. The present reaction can be successfully applied to intermolecular [2 + 2] cross-cycloaddition of ß-halogenostyrenes, which cannot be effectively achieved by the hitherto reported representative organophotoredox catalysts.

Base-mediated rearrangement of free aromatic hydroxamic acids (ArCO-NHOH) to anilines.

Without using activating agents, a variety of free aromatic hydroxamic acids could be rearranged to aromatic amines in the presence of base alone.

Fieldservers and Sensor Service Grid as Real-time Monitoring Infrastructure for Ubiquitous Sensor Networks.

The fieldserver is an Internet based observation robot that can provide an outdoor solution for monitoring environmental parameters in real-time. The data from its sensors can be collected to a central server infrastructure and published on the Internet. The information from the sensor network will contribute to monitoring and modeling on various environmental issues in Asia, including agriculture, food, pollution, disaster, climate change etc. An initiative called Sensor Asia is developing an infrastructure called Sensor Service Grid (SSG), which integrates fieldservers and Web GIS to realize easy and low cost installation and operation of ubiquitous field sensor networks.

Characterization of peach tree crown by using high-resolution images from an unmanned aerial vehicle.

In orchards, measuring crown characteristics is essential for monitoring the dynamics of tree growth and optimizing farm management. However, it lacks a rapid and reliable method of extracting the features of trees with an irregular crown shape such as trained peach trees. Here, we propose an efficient method of segmenting the individual trees and measuring the crown width and crown projection area (CPA) of peach trees with time-series information, based on gathered images. The images of peach trees were collected by unmanned aerial vehicles in an orchard in Okayama, Japan, and then the digital surface model was generated by using a Structure from Motion (SfM) and Multi-View Stereo (MVS) based software. After individual trees were identified through the use of an adaptive threshold and marker-controlled watershed segmentation in the digital surface model, the crown widths and CPA were calculated, and the accuracy was evaluated against manual delineation and field measurement, respectively. Taking manual delineation of 12 trees as reference, the root-mean-square errors of the proposed method were 0.08 m (R 2 = 0.99) and 0.15 m (R 2 = 0.93) for the two orthogonal crown widths, and 3.87 m2 for CPA (R 2 = 0.89), while those taking field measurement of 44 trees as reference were 0.47 m (R 2 = 0.91), 0.51 m (R 2 = 0.74), and 4.96 m2 (R 2 = 0.88). The change of growth rate of CPA showed that the peach trees grew faster from May to July than from July to September, with a wide variation in relative growth rates among trees. Not only can this method save labour by replacing field measurement, but also it can allow farmers to monitor the growth of orchard trees dynamically.

Vocal tract length perturbation and its application to male-female vocal tract shape conversion.

An alternative and complete derivation of the vocal tract length sensitivity function, which is an equation for finding a change in formant frequency due to perturbation of the vocal tract length [Fant, Quarterly Progress and Status Rep. No. 4, Speech Transmission Laboratory, Kungliga Teknisha Hogskolan, Stockholm, 1975, pp. 1-14] is presented. It is based on the adiabatic invariance of the vocal tract as an acoustic resonator and on the radiation pressure on the wall and at the exit of the vocal tract. An algorithm for tuning the vocal tract shape to match the formant frequencies to target values, such as those of a recorded speech signal, which was proposed in Story [J. Acoust. Soc. Am. 119, 715-718 (2006)], is extended so that the vocal tract length can also be changed. Numerical simulation of this extended algorithm shows that it can successfully convert between the vocal tract shapes of a male and a female for each of five Japanese vowels.

Tandem Brook Rearrangement/Silicon Polonovski Reaction via Oxidative Generation of Ammonium Ylides.

A tandem Brook rearrangement/silicon Polonovski reaction has been achieved by in situ generation of ammonium ylides via the oxidation of α-silyl-tertiary amines. Furthermore, we found that the oxidation of N-(1-cyano-1-silyl)methyl-tertiary amines with peracids induced the tandem Brook rearrangement/silicon Polonovski reaction/fragmentation to give formamide derivatives in moderate yields.

Synthesis of tricyclic pyrano[2,3-e]isoindolin-3-ones as the core structure of stachybotrin A, B, and C.

The substituted tricyclic pyrano[2,3-e]isoindolin-3-ones and , as the core structure of stachybotrin A, B, and C (), have been regioselectively synthesized for the first time by a short route which involved Mannich reaction and Claisen rearrangement.

Web GIS in practice IV: publishing your health maps and connecting to remote WMS sources using the Open Source UMN MapServer and DM Solutions MapLab.

Open Source Web GIS software systems have reached a stage of maturity, sophistication, robustness and stability, and usability and user friendliness rivalling that of commercial, proprietary GIS and Web GIS server products. The Open Source Web GIS community is also actively embracing OGC (Open Geospatial Consortium) standards, including WMS (Web Map Service). WMS enables the creation of Web maps that have layers coming from multiple different remote servers/sources. In this article we present one easy to implement Web GIS server solution that is based on the Open Source University of Minnesota (UMN) MapServer. By following the accompanying step-by-step tutorial instructions, interested readers running mainstream Microsoft(R) Windows machines and with no prior technical experience in Web GIS or Internet map servers will be able to publish their own health maps on the Web and add to those maps additional layers retrieved from remote WMS servers. The 'digital Asia' and 2004 Indian Ocean tsunami experiences in using free Open Source Web GIS software are also briefly described.

Use of a remote sensing-based geographic information system in the characterizing spatial patterns for Anopheles minimus A and C breeding habitats in western Thailand.

A remote sensing (RS)-based Geographic Information System (GIS) was used to characterize the breeding habitats of Anopheles minimus species A and C in five different districts of Kanchanaburi Province in western Thailand. The GIS and RS were used to monitor the area for the presence and absence of An. minimus A and C in five major land areas, forest, agriculture, urban, water and bare land. The results show that An. minimus A survives both in dense canopy forest and in open fields where agriculture is dominant. A scatter plot of land-use/land-cover for An. minimus, considering proximities to the forest and proximities to agriculture, suggests that An. minimus A has a wider habitat preference, ranging from dense canopy forest to open agricultural fields. A scatter plot for An. minimus C, on the other hand, showed a narrow habitat preference. A scatter plot for proximities performed on separate populations of An. minimus species A, one in the north and the other in the south, showed that there was an association in the northern population with the forest and in the southern population with agricultural areas. There were no statistically significant differences in the scatter plot of proximities to urban areas and water bodies with the An. minimus A north, south, and An. minimus C. LANDSAT TM satellite data classification was used to identify larval habitats that produce An. minimus A and C and analyze proximities between land-use/land-cover classes and locations of larval habitats. An. minimus A has a wide habitat preference, from dense canopy forest to open agricultural fields, while An. minimus C has a narrow habitat preference.