450 research outputs found
The developmental process of flood shoals based on observations in Toufutsu lake, Japan
Recently, the flood tidal sand bars have been developed at the entrance channel of Toufutsu Lake located along Okhotsk Sea in Hokkaido, and they affect flood control, inland water fisheries in lake, and so forth. In this study, we aimed to reveal the developmental process of sand bars by observations, which are velocity observation, water level observation, bed material investigation and video monitoring. Followings were major accomplishments of this study. (1) The maximum magnitude of reverse velocity at St.400 in the entrance channel during the periods of flood-tide was faster than that of normal velocity during the periods of ebb-tide. (2) The relationship between velocity at SP400 and friction velocity at SP400 during the periods of flood-tide is different from that during the periods of ebb-tide. (3) The\ud
flood tidal sand bars at the entrance channel of Toufutsu Lake were developed by not only sea waves, but also adverse tidal current in the spring-tide
Successful treatment of severe accidental hypothermia with cardiac arrest for a long time using cardiopulmonary bypass - report of a case
Accidental hypothermia is defined as an unintentional decrease in body temperature to below 35°C, and cases in which temperatures drop below 28°C are considered severe and have a high mortality rate. This study presents the case of a 57-year-old man discovered drifting at sea who was admitted to our hospital suffering from cardiac arrest. Upon admittance, an electrocardiogram indicated asystole, and the patient's temperature was 22°C. Thirty minutes of standard CPR and external rewarming were ineffective in raising his temperature. However, although he had been in cardiac arrest for nearly 2 h, it was decided to continue resuscitation, and a cardiopulmonary bypass (CPB) was initiated. CPB was successful in gradually rewarming the patient and restoring spontaneous circulation. After approximately 1 month of rehabilitation, the patient was subsequently discharged, displaying no neurological deficits. The successful recovery in this case suggests that CPB can be considered a useful way to treat severe hypothermia, particularly in those suffering from cardiac arrest
New neurons use Slit-Robo signaling to migrate through the glial meshwork and approach a lesion for functional regeneration
After brain injury, neural stem cell–derived neuronal precursors (neuroblasts) in the ventricular-subventricular zone migrate toward the lesion. However, the ability of the mammalian brain to regenerate neuronal circuits for functional recovery is quite limited. Here, using a mouse model for ischemic stroke, we show that neuroblast mi-gration is restricted by reactive astrocytes in and around the lesion. To migrate, the neuroblasts use Slit1-Robo2 signaling to disrupt the actin cytoskeleton in reactive astrocytes at the site of contact. Slit1-overexpressing neu-roblasts transplanted into the poststroke brain migrated closer to the lesion than did control neuroblasts. These neuroblasts matured into striatal neurons and efficiently regenerated neuronal circuits, resulting in functional recovery in the poststroke mice. These results suggest that the positioning of new neurons will be critical for func-tional neuronal regeneration in stem/progenitor cell–based therapies for brain injury
FAK acts as a suppressor of RTK-MAP kinase signalling in Drosophila melanogaster epithelia and human cancer cells
Receptor Tyrosine Kinases (RTKs) and Focal Adhesion Kinase (FAK) regulate multiple signalling pathways, including mitogen-activated protein (MAP) kinase pathway. FAK interacts with several RTKs but little is known about how FAK regulates their downstream signalling. Here we investigated how FAK regulates signalling resulting from the overexpression of the RTKs RET and EGFR. FAK suppressed RTKs signalling in Drosophila melanogaster epithelia by impairing MAPK pathway. This regulation was also observed in MDA-MB-231 human breast cancer cells, suggesting it is a conserved phenomenon in humans. Mechanistically, FAK reduced receptor recycling into the plasma membrane, which resulted in lower MAPK activation. Conversely, increasing the membrane pool of the receptor increased MAPK pathway signalling. FAK is widely considered as a therapeutic target in cancer biology; however, it also has tumour suppressor properties in some contexts. Therefore, the FAK-mediated negative regulation of RTK/MAPK signalling described here may have potential implications in the designing of therapy strategies for RTK-driven tumours
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Recent Results From a Si/CdTe Semiconductor Compton Telescope
We are developing a Compton telescope based on high resolution Si and CdTe detectors for astrophysical observations in sub-MeV/MeV gamma-ray region. Recently, we constructed a prototype Compton telescope which consists of six layers of double-sided Si strip detectors and CdTe pixel detectors to demonstrate the basic performance of this new technology. By irradiating the detector with gamma-rays from radio isotope sources, we have succeeded in Compton reconstruction of images and spectra. The obtained angular resolution is 3.9{sup o} (FWHM) at 511 keV, and the energy resolution is 14 keV (FWHM) at the same energy. In addition to the conventional Compton reconstruction, i.e., drawing cones in the sky, we also demonstrated a full reconstruction by tracking Compton recoil electrons using the signals detected in successive Si layers. By irradiating {sup 137}Cs source, we successfully obtained an image and a spectrum of 662 keV line emission with this method. As a next step, development of larger double-sided Si strip detectors with a size of 4 cm x 4 cm is underway to improve the effective area of the Compton telescope. We are also developing a new low-noise analog ASIC to handle the increasing number of channels. Initial results from these two new technologies are presented in this paper as well
Dizajniranje i vrednovanje bioadhezijskog filma za transdermalnu isporuku propranolol hidroklorida
The objective of the study was to develop a suitable transdermal delivery system for propranolol hydrochloride (PPL) via employing chitosan as a film former. Drug concentration uniformity, thickness, moisture uptake capacity and skin bioadhesion of the films were characterized. The effects of chitosan and PPL concentration and different penetration enhancers on the release and permeation profiles from the films were investigated. Skin irritation of the candidate film was evaluated.
Chitosan film (PPL 2 mg cm2, chitosan 2 % m/m, cineol 10 %, m/m) was found non-irritant and achieved 88.2 % release after 8 hours in phosphate buffer. Significant high (p < 0.001) permeation of PPL through rat skin was obtained using this film compared to the film without enhancer (about 8 times enhancement factor), making it a promising transdermal delivery system for PPL.Cilj rada bio je razvoj pogodnog transdermalnog sustava na bazi kitozana za isporuku propranolol hidroklorida (PPL). Svim pripravcima ispitana je jednoličnost udjela lijeka, debljina, sposobnost vlaženja i bioadhezivnost na kožu. Ispitivan je i utjecaj kitozana, koncentracije PPL-a i sredstva za povećanje permeacije na oslobađanje i permeacijski profil, te potencijalni iritacijski učinak na kožu. Iz kitozanskog filma (PPL 2 mg cm2, 2 %, m/m, kitozana i 10 %, m/m, cineola), koji nije djelovao iritabilno, postignuto je 88,2 % oslobađanja nakon 8 sati u fosfatnom puferu. S ovim pripravkom postignuta je i vrlo značajna (p < 0,001) permeacija PPL kroz kožu štakora, oko osam puta veća u usporedbi s filmom bez sredstva za povećanje permeacije. Pripravak bi se mogao upotrijebiti za transdermalnu isporuku PPL
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