Reply [to “Comment on ‘Motion of the sources for Type 2 and Type 4 radio bursts and flare-associated interplanetary disturbances’ by K. Sakurai and J. K. Chao”]

Sakurai, Kunitomo

doi:10.1029/ja079i031p04825

Cited by 10 publications

(19 citation statements)

References 3 publications

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“…is quite different from that of magnetic bottles which have been estimated here (e.g., Dulk et al, 1971;Sakurai and Chao, 1973;Sakurai, 1973b).…”

Section: Viewed From Northcontrasting

confidence: 47%

“…In the case of the 4 November 1968 proton event, the speed of type II radio source is estimated as ~2600 km s --I by Sakurai et al (1973) using the plasma distribution in the outer solar atmosphere (Stelzried et al, 1970). Moreover, the mean speed of the interplanetary shock wave associated with a flare, which occurred at 0513 UT, is estimated as ~650 kms -1 (Sakurai et al, 1973). These two speeds estimated here are much higher than that estimated by Schatten for an associated magnetic bottle.…”

Section: Relation Between Expanding Magnetic Bottles and Type II Radimentioning

confidence: 99%

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The initial stage of development of type IV radio bursts and the relation to expanding magnetic bottles

Sakurai

1973

Sol Phys

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Using the observed data for wide-band type IV solar radio bursts, the onset time differences between the microwave and metric frequencies and the peak flux intensities of the metric component are analyzed as a function of the longitudinal position of the associated flares on the solar disk. It is shown that this time difference is dependent on the position of the associated flare and that the peak flux intensity reaches maximum when a flare occurs in the region 10 to 40 ~ west of the central meridian of the solar disk. These results are explained by taking into account the eastward expansion of magnetic bottles which trap mildly relativistic electrons responsible for type IV bursts. Discussion is given on the relation between these magnetic bottles and shock waves which excite type II radio bursts.

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“…is quite different from that of magnetic bottles which have been estimated here (e.g., Dulk et al, 1971;Sakurai and Chao, 1973;Sakurai, 1973b).…”

Section: Viewed From Northcontrasting

confidence: 47%

Section: Relation Between Expanding Magnetic Bottles and Type II Radimentioning

confidence: 99%

The initial stage of development of type IV radio bursts and the relation to expanding magnetic bottles

Sakurai

1973

Sol Phys

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“…17,18) The vehicle (base: decamethylcyclopentasiloxane), a UVB sunscreen (3% 2-ethylhexyl 4-methoxycinnamateϩbase), and a UVA&UVB sunscreen (10% silicone coated zinc oxideϩ3% 2-ethylhexyl 4-methoxycinnamateϩbase) were tested. According to the Japan Cosmetic Industry Association standards, the Protection Factor of UVA (PFA) in the UVA sunscreen sample was approximately 6(PAϩϩ), representing an 83.3% UVA protection efficacy, while the UVB sunscreen sample had an approximate Sun Protection Factor (SPF) of 20.…”

Section: Animalsmentioning

confidence: 99%

The Effect of Sunscreen on Skin Elastase Activity Induced by Ultraviolet-A Irradiation

Tsukahara

Moriwaki

Hotta

et al. 2005

Biological & Pharmaceutical Bulletin

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To elucidate the mechanism underlying skin wrinkle formation, one feature of photoaging, we recently performed a study in which rat hind limb (plantar) skin was short-term chronically irradiated with ultraviolet-B (UVB) at 1 MED or lower. That study showed that elastase activity was increased in the rat hind limb skin 1) and changed the 3-dimensional structure of dermal elastic fibers, which bent the fibers responsible for skin elasticity 2,3) and thus decreased skin elasticity, forming wrinkles. 1,4,5) We also reported that this series of events could be inhibited by application of an elastase activity-inhibiting agent after UVB irradiation. 1,6,7) Inhibition of the UVB-induced increase in skin elastase activity prevented by the agent maintained the linearity of dermal elastic fibers and inhibited the decrease in skin elasticity, resulting in the inhibition of wrinkle formation. 1,6,7) This finding suggested that application of an elastase inhibitor immediately after UVB exposure would inhibit photoaging of the skin, mainly wrinkles.It has been shown that chronic UVB irradiation of the dorsal skin forms wrinkles in hairless mice 8,9) and that chronic ultraviolet-A (UVA) irradiation forms mainly sags. 8,9) In animal models, chronic UVA irradiation increased skin elastase activity and destroyed the 3-dimensional structure of dermal elastic fibers, decreasing skin elasticity, similarly to UVB irradiation.5,9-11) There have been many reports that the application of sunscreens before UV exposure inhibits the photoaging of skin in animal models and in humans. 8,[12][13][14][15][16] Based on those findings, application of a sunscreen before UV exposure might be expected to inhibit an increase in skin elastase activity even when UVA is continuously irradiated. It is therefore important and interesting to investigate the effects of chronic UVA irradiation on elastase activity in skin protected with sunscreens before irradiation in an animal model.The purpose of this study was to investigate effects of the photoprotection from UVA by topically applied sunscreens on skin elastase activity and on skin properties. MATERIALS AND METHODSAnimals Forty female HR/ICR hairless mice were used. This strain was derived by crossing 6 week old hairless mice (HR/HR) originally obtained from Nisseiken Corp (Tokyo, Japan) with the albino strain HaM/ICR. The HR/ICR strain represents a line maintained under clean conventional conditions in our laboratory by hairless brother/haired sister mating for several years. All experiments were performed with hairless female mice only, which had free access to food and water. They were housed in rooms where the lighting (without UVB emission) was automatically regulated on a 12 h light and dark cycle. The experimental protocol was approved by the Ethics Review Committee for Animal Experimentation of Kao Corp.UVA Irradiation UVA irradiation was carried out as described previously.9,10) Briefly, mice were irradiated using a bank of 12 Toshiba BL lamps with a glass filter (0.5 cm thick) for UVA (peak of...

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“…Three types of nonthermal radio bursts are associated with the CME/flare Events (Sakurai, 1974;White, 2007;Gopalswamy, 2011):…”

Section: Introductionmentioning

confidence: 99%

Interplanetary Type IV Bursts

2016

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We study the characteristics of moving type IV radio bursts which extend to the hectometric wavelengths (interplanetary type IV or type IV IP bursts) and their relationship with energetic phenomena on the Sun. Our dataset comprises 48 interplanetary type IV bursts observed with the Radio and Plasma Wave Investigation (WAVES) instrument onboard Wind in the 13.825 MHz-20 kHz frequency range. The dynamic spectra of the Radio Solar Telescope Network (RSTN), the Nançay Decametric Array (DAM), the Appareil de Routine pour le Traitement et l' Enregistrement Magnetique de l' Information Spectral (ARTEMIS-IV), the Culgoora, Hiraiso and Izmiran Radio Spectrographs were used to track the evolution of the events in the low corona. These were supplemented with soft X-ray (SXR) flux-measurements from the Geostationary Operational Environmental Satellite (GOES) and coronal mass ejections (CME) data from the Large Angle and Spectroscopic Coronagraph (LASCO) onboard the Solar and Heliospheric Observatory (SOHO). Positional information of the coronal bursts was obtained by the Nançay radioheliograph (NRH). We examined the relationship of the type IV events with coronal radio bursts, CMEs and SXR flares. The majority of the events (45) were characterized as compact; their duration was on average 106 minutes. This type of events was, mostly, associated with M-and X-class flares (40 out of 45) and fast CMEs; 32 of these events had CMEs faster than 1000 km s −1 . Furthermore, in 43 compact events the CME was, possibly, subjected to reduced aerodynamic drag as it was propagating in the wake of a previous CME. A minority (three) of long lived type IV IP bursts was detected, with duration from 960 minutes to 115 hours. These events are referred to as extended or long duration and appear to replenish their energetic electron content, possibly from electrons escaping from the corresponding coronal type IV bursts. The latter were found to persist on the disk, for tens of hours to days. Prominent among them was the unusual interplanetary type IV burst of 18-23 May 2002, which is the longest event in the Wind /WAVES catalog. The three extended events were, usually, accompanied by a number of flares, of GOES class C in their majority, and of CMEs, many of which were slow and narrow.

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Reply [to “Comment on ‘Motion of the sources for Type 2 and Type 4 radio bursts and flare-associated interplanetary disturbances’ by K. Sakurai and J. K. Chao”]

Cited by 10 publications

References 3 publications

The initial stage of development of type IV radio bursts and the relation to expanding magnetic bottles

The initial stage of development of type IV radio bursts and the relation to expanding magnetic bottles

The Effect of Sunscreen on Skin Elastase Activity Induced by Ultraviolet-A Irradiation

Interplanetary Type IV Bursts

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