The diazo-transfer reaction of nonactivated ketone under mild reaction conditions was developed. Various nonactivated ketones such as aryl methyl ketones, -alkyl methyl ketones, and cyclic ketones were transformed into their corresponding α-diazoketones in one step by treating 2-azido-1,3-bis(2,6-diisopropylphenyl)imidazolium hexafluorophosphate (IPrAP) in the presence of PrNH in ethylene glycol. In the reaction of IPrAP with -alkyl methyl ketone and -alkyl aryl ketones, migratory amidation proceeded under the reaction conditions to afford the corresponding amides.
View Article and Find Full Text PDFChem Pharm Bull (Tokyo)
July 2023
In this study, we developed mild conditions for the synthesis of an aryl thioether via aromatic substitution using aryl halides, which is a process that has rarely been studied. Aromatic substrates such as aryl fluorides activated with a halogen substituent are difficult to use for substitution reactions, but by using 18-crown-6-ether as an additive, these were successfully converted to their corresponding thioether products. Under the conditions we established, in addition to a wide variety of thiols, less-toxic and odorless disulfides could be used directly as nucleophiles at 0 to 25 °C.
View Article and Find Full Text PDFThe perceptual simultaneity range for two diotically presented tones increases with decreasing frequency separation of the two tones from approximately 0.5 Bark. As the present study of two frequency regions shows, this effect is not observed when the two tones are not presented to the same ear, i.
View Article and Find Full Text PDFIn this study, we developed a method for etherification via aromatic substitution at the ipso-position of an electron-withdrawing group (EWG) that exists at the meta-position of another EWG. To heighten the reactivity of the substitution reaction, we added a -BuOK solution in tetrahydrofuran (THF) to a mixture of an aromatic substrate, an alcoholic nucleophile, and 18-crown-6-ether in dimethylformamide (DMF), which proved to be a particularly effective sequence. Under the conditions we established, aromatic substrates that are difficult to use for substitution reactions such as aryl fluorides activated with either a bromide or a chloride substituent were aptly converted to corresponding ether products at 25 °C.
View Article and Find Full Text PDFIn this study, mild conditions for aromatic substitutions during the syntheses of aryl ethers were developed. In the reaction conditions, the choices of solvent, base, and the sequence for the addition of the reagents proved important. A wide variety of alcohols were used directly as nucleophiles and smoothly reacted with aryl chlorides that possessed either a nitro or a cyano group at either the ortho- or para-position.
View Article and Find Full Text PDFPrevious studies have indicated that extended exposure to a high level of sound might increase the risk of hearing loss among professional symphony orchestra musicians. One of the major problems associated with musicians' hearing loss is difficulty in estimating its risk simply on the basis of the physical amount of exposure, i.e.
View Article and Find Full Text PDFYearly changes in radiocesium ((137)Cs) contamination, primarily due to the Fukushima accident of March 2011, were observed in the foliar parts of 10 common woody species in Japan (Chamaecyparis obtusa, Cedrus deodara, Pinus densiflora, Cryptomeria japonica, Phyllostachys pubescens, Cinnamomum camphora, Metasequoia glyptostroboides, Prunus × yedoensis, Acer buergerianum, and Aesculus hippocastanum). The samples were obtained from Abiko (approximately 200 km SSW of the Fukushima Dai-ichi Nuclear Power Plant) during each growing season between 2011 and 2013, and the foliar parts were examined based on their year of expansion and location in each trees. The radiocesium concentrations generally decreased with time; however, the concentrations and rates of decrease varied among species, age of foliar parts, and locations.
View Article and Find Full Text PDFThe concentration and particle size distribution of 19 major polycyclic aromatic hydrocarbons (PAHs) emitted by thermal cooking were investigated. Corn, trout, beef, prawns, and pork were selected for grilling. The PAHs in the oil mist emitted when the food was grilled were collected according to particle size range and analysed by GC/MS.
View Article and Find Full Text PDFThe purpose of this study is to investigate the sufficient "similarity" between consecutive auditory events for the auditory system to define the fundamental period for pitch perception. It is possible to contaminate the periodicity of harmonic complex tones by scaling the impulse response in the time domain at every other cycle. Scale-alternating wavelet sequences (SAWS) in which two impulse responses with different scaling factors alternated were generated based on impulse responses obtained from Japanese vowels spoken by a male speaker.
View Article and Find Full Text PDFPrevious studies have suggested that professional musicians comprehend features of music-derived sound even if the sound sequence lacks the traditional temporal structure of music. We tested this hypothesis through behavioral and functional brain imaging experiments. Musicians were better than nonmusicians at identifying scrambled pieces of piano music in which the original temporal structure had been destroyed.
View Article and Find Full Text PDFJ Appl Physiol (1985)
September 2012
Tenomodulin (Tnmd, also called Tendin) is classified as a type II transmembrane glycoprotein and is highly expressed in developing as well as in mature tendons. Along with scleraxis (scx), Tnmd is a candidate marker gene for tenocytes. Its function is unknown, but it has been reported to have anti-angiogenic properties.
View Article and Find Full Text PDFUnderstanding the mechanisms that regulate mechanosensitivity in osteoblasts is important for controlling bone homeostasis and the development of new drugs to combat bone loss. It is believed that prestress or force generation (the tensile stress within the cell body) plays an important role in regulating cellular mechanosensitivity. In the present study, a three-dimensional (3D) collagen culture was used to monitor the change in prestress of the osteoblast-like cells.
View Article and Find Full Text PDFTendon overuse injuries are a major source of clinical concern. Cyclic loading causes material damage and induces biochemical responses in tendon. The purpose of this study was to examine the biochemical and biomechanical tendon response after applying cyclical loading over varying durations.
View Article and Find Full Text PDFBackground: Tendon overuse injuries are a common occurrence; accounting for a large proportion of occupational and athletic injuries. The concept examined in this study is the role of load-induced intrinsic inflammation to the mechanism of these injuries. This study examined the influence of cyclical loading on the mechanical properties, cell viability, and inflammatory mediators of cultured tendon explants.
View Article and Find Full Text PDFJ Cell Biochem
September 2005
Response to external stimuli such as mechanical signals is critical for normal function of cells, especially when subjected to repetitive motion. Tenocytes receive mechanical stimuli from the load-bearing matrix as tension, compression, and shear stress during tendon gliding. Overloading a tendon by high strain, shear, or repetitive motion can cause matrix damage.
View Article and Find Full Text PDFAm J Physiol Cell Physiol
October 2004
Sympathetic efferent nerves are present in tendons, but their function within tendon is unknown. alpha(1)-Adrenoceptors are expressed by a variety of cell types. In the presence of norepinephrine (NE), adrenoceptors activate G(q/11) signaling pathways that subsequently increase intracellular Ca(2+) concentration ([Ca(2+)](ic)).
View Article and Find Full Text PDFBackground Context: Whole body vibration is an important factor contributing to low back and radicular pain. Vibratory loading as a mechanical stimulus is transferred to connective tissues as energy from ground reaction forces, as well as a direct input from the use of motorized tools and vehicles. Extracellular matrix degradation parallels increased age and mechanical stimuli resulting in disc degeneration and eventual spinal deformity.
View Article and Find Full Text PDFMechanical forces regulate the developmental path and phenotype of a variety of tissues and cultured cells. Vibratory loading as a mechanical stimulus occurs in connective tissues due to energy returned from ground reaction forces, as well as a mechanical input from use of motorized tools and vehicles. Structures in the spine may be particularly at risk when exposed to destructive vibratory stimuli.
View Article and Find Full Text PDFTo provide a perceptual framework for the objective evaluation of durational rules in speech synthesis, two experiments were conducted to investigate the differences between vowel (V) onsets and V-offsets in their functions of marking the perceived temporal structure of speech. The first experiment measured the detectability of temporal modifications given in four-mora (CVCVCVCV) Japanese words. In the V-onset condition, the inter-onset intervals of vowels were uniformly changed (either expanded or reduced) while their inter-offset intervals were preserved.
View Article and Find Full Text PDFTendon cells receive mechanical signals from the load bearing matrices. The response to mechanical stimulation is crucial for tendon function. However, overloading tendon cells may deteriorate extracellular matrix integrity by activating intrinsic factors such as matrix metalloproteinases (MMPs) that trigger matrix destruction.
View Article and Find Full Text PDFOveruse injuries and trauma in tendon often involve acute or chronic pain and eventual matrix destruction. Anti-inflammatory drugs have been used as a treatment, however, the cellular and molecular mechanisms of the destructive processes in tendon are not clearly understood. It is thought that an inflammatory event may be involved as an initiating factor.
View Article and Find Full Text PDFForces applied to tendon during movement cause cellular deformation, as well as fluid movement. The goal of this study was to test the hypothesis that rabbit tendon fibroblasts detect and respond to fluid-induced shear stress. Cells were isolated from the paratenon of the rabbit Achilles tendon and then subjected to fluid flow at 1 dyn/cm(2) for 6h in a specially designed multi-slide flow device.
View Article and Find Full Text PDFLittle is known about the factors that initiate and propagate tendon overuse injuries, but chronic inflammation and matrix destruction have been implicated. The purpose of this study was to evaluate the production of cyclooxygenase II (COX-2) and matrix metalloproteinases (MMPs) by tendon cells exposed to cyclic strain and inflammatory cytokines in vitro. Rabbit Achilles tendon cells were subjected to a stretching protocol with 5% elongation at 0.
View Article and Find Full Text PDFHuman subjective acceptability of durational distortions in speech segments or portions is significantly affected by various segmental and sequential properties, e.g., the vowel color and temporal position in a word [Kato et al.
View Article and Find Full Text PDFChronic inflammation and altered mechanical loading are implicated as contributors to intervertebral disc degeneration. Biomechanical and biochemical factors play a role in disc degeneration but have received limited study. Mechanically, intervertebral discs are sheared during bending or twisting of the trunk.
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