388 research outputs found

    Effects of wind fence protection on the growth and regeneration of coastal black pine (Pinus thunbergii Parl.)

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    防風柵による保護がクロマツの成長と更新に与える影響を明らかにするため、鳥取県北条砂丘に成立しているクロマツ海岸林において2つのプロットを設置した。1つのプロットは、海側に防風柵があり、もう1つのプロットは防風柵のないものである。それぞれのプロットで、樹高、胸高直径、主軸の伸長成長量、樹幹の傾き、枯損率、樹冠面積を調査した。また、それぞれのプロット内で天然更新していた稚樹と幼樹の数と樹齢を調べた。 樹高、胸高直径、主軸の1年当りの伸長成長量は、防風柵のないプロットより、防風柵のあるプロットで大きかった。さらに、樹幹の傾きと枯損率は、防風柵のあるプロットで小さかった。稚樹と幼樹の密度と樹齢は、防風柵のあるプロットで大きかった。 これらのことから、防風柵は、潮風を防ぐ高い機能により、海岸に成育するクロマツの成長を塩風から保護していると推察された。防護策のある林分における樹冠被覆の適切な管理は、海岸林の海側であっても、天然更新を可能にすることができる。従って、防風柵による風よけの機能は、常に効果的であることが期待できる

    Age-dependent vulnerability to ischemia-reperfusion injury of cyanotic myocardium in a chronic hypoxic rat model

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    This study evaluated the effects of chronic hypoxia from birth on the resistance of rat hearts to global ischemia, with special emphasis on the duration of hypoxia. Male Wistar rats were housed from birth for 4 weeks or 8 weeks either in a hypoxic environment (FiO20.12) or in ambient air (8 animals for each group). Isolated rat hearts were perfused for 40 min with oxygenated Krebs-Henseleit buffer, subjected to 20 min global no-flow ischemia at 37, and then underwent 40 min of reperfusion. A non-elastic balloon was inserted into the left ventricle and inflated until the pre-ischemic LVEDP rose to 8mmHg. Cardiac function was measured before and after ischemia. The post-ischemic percent recovery of LVDP in hypoxic hearts was worse than in normoxic hearts (4 weeks:55+/-7 vs. 96+/-3%, p0.01;8 weeks:40+/-5 vs. 92+/-4%, p0.01), and was worst in the 8-week-hypoxic hearts. Similarly, the percent recovery of dP/dt in the hypoxic hearts was lower than in the normoxic hearts (4 weeks:51+/-5 vs. 96+/-7%, p0.01;8 weeks:31+/-6 vs. 92+/-7%, p0.01), and was lowest in the 8-week-hypoxic hearts. In conclusion, cyanotic myocardium revealed an age-dependent vulnerability to ischemia-reperfusion injury in a chronic hypoxic rat model.</p

    Superoxide Anion Radical Scavenging Activities of Herbs and Pastures in Northern Japan Determined Using Electron Spin Resonance Spectrometry

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    Free radicals are not only destructive to the living cells but also reduce the quality of animal products through oxidation. As a result the superoxide anion radical (O2・-), one of the most destructive reactive oxygen species, is a matter of concern for the animal scientists as well as feed manufacturers to ensure the quality of product to reach consumers demand. The superoxide anion radical scavenging activities (SOSA) of water and MeOH extracts of 2 herbs and 9 pasture samples collected from lowland and highland swards were determined against a 5,5-dimethyl-1-pyroline-N-oxide-O2・-spin adduct based on a hypoxanthine-xanthine oxidase reaction using electron spin resonance spectrometry. Both the water and MeOH extracted SOSA differed among the herbs and pastures. Species and altitudinal variations were observed between extraction methods. The herbs were higher in both water and MeOH extracted SOSA than the pastures except for water extracts of one pasture, white clover (Trifolium repens L.). Among the pastures, quackgrass (Agrophyron repens L.) showed higher SOSA in both the MeOH and water extracts, and timothy (Phleum pretense L.) showed higher MeOH extracted SOSA. It is apparent that the kind and amount of antioxidants differ among herbs and pastures. Animal health and quality of animal products could be improved by adequate selection and combining of herbs and pastures having higher SOSA

    Low X-ray Efficiency of a Young High-B Pulsar PSR J1208-6238 Observed with Chandra

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    High magnetic field (high-B) pulsars are key sources to bridge magnetars and conventional rotation powered pulsars, and thus to understand the origin of magnetar activities. We have estimated a tight upper-limit on the X-ray flux of one of the youngest high-B pulsars PSR J1208-6238 for the first time; a Chandra 10 ks observation shows no significant source. Depending on the emission models, the 3sigma upper-limit on the intrinsic 0.5-7 keV flux to (2.2-10.0)e-14 erg/s/cm2.Comment: 7 pages, 6 figures, Ap&SS, accepte

    Application of a microfluidic sperm sorter to the in-vitro fertilization of porcine oocytes reduced the incidence of polyspermic penetration

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    The objective of this study was to use a microfluidic sperm sorter (MFSS), designed to isolate motile human spermatozoa with laminar flows (no centrifugation), for porcine IVF. Boar spermatozoa were diluted at 1 x 10(8) with a diluent containing 20% seminal fluid and flowed with modified TCM-199 (mM199, with 5 mM caffeine) to introduce motile sperm into the exit chamber for IVF. In Experiment 1, after flowing for 5 min, sperm concentration varied significantly among specific sites within the MFSS collecting chamber (range, 0.8 +/- 0.5 x 10(4) to 575.0 +/- 56.3 x 10(4) cells/mL; mean +/- SEM). In Experiment 2, when porcine IVM oocytes were placed at three locations in the MFSS exit chamber (where only motile spermatozoa accumulated) and subsequently cultured in caffeine-free mM199 for 8 h, sperm penetration rate was not significantly different among places (86.1 +/- 10.5 to 100%), but the monospermic penetration rate was lower (P < 0.05) in oocytes 3.5 mm from the exit position (12.5 +/- 4.8%) than those at 7.5 mm (53.1 +/- 6.0%) or further (41.9 +/- 2.8%) from the exit. In Experiment 3, the normal fertilization index (ratio of monospermic oocytes to number of oocytes examined) 8 h after insemination was higher (P < 0.05) in the MFSS-IVF system (0.375 +/- 0.040) than both standard IVF and transient IVF (0.222 +/- 0.028 and 0.189 +/- 0.027, respectively, with co-culture for 8 h and for 5 min). Developmental competence of fertilized oocytes (blastocyst formation) was higher (P < 0.05) in the MFSS-IVF system (40.9 +/- 2.3%) than in either standard or transient IVF (22.6 +/- 1.4 and 33.7 +/- 3.5%). In conclusion, brief co-culture of porcine oocytes with spermatozoa gradually accumulated in the MFSS chamber improved the efficiency of producing monospermic fertilized embryos and blastocysts. Furthermore, efficiencies were significantly affected by oocyte location within the chamber

    Cardiac erosion after catheter closure of atrial septal defect: Septal malalignment may be a novel risk factor for erosion

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    AbstractPericardial tamponade occurred 3 days after the catheter closure of an atrial septal defect (ASD) using Amplatzer Septal Occluder (St. Jude Medical, St. Paul, MN, USA). Before the closure, two-dimensional and real-time three-dimensional transesophageal echocardiography demonstrated a deficient aortic rim and atrial septal malalignment. Perforation of the right atrium toward the non-coronary sinus of the aortic root was confirmed at the emergent surgery. Cardiac erosion is one of the most catastrophic complications in ASD patients undergoing catheter closure with Amplatzer Septal Occluder. Hence, several risk factors for this complication are discussed and identified. Oversized device deployment and a deficient aortic rim are accepted factors potentially causing cardiac erosion. Besides, atrial septal malalignment, which is a morphological characteristic of ASD, may be a novel risk factor for cardiac erosion.<Learning objective: Cardiac erosion is a potentially lethal complication when catheter closure of atrial septal defects using Amplatzer Septal Occluder (St. Jude Medical, St. Paul, MN, USA) is provided to the patients. However, mechanisms of this complication remain to be completely elucidated. Atrial septal malalignment may be one of the novel risk factors for this catastrophic complication.

    O-arm Navigation-Guided Surgical Resection and Posterior Fixation for a Large Sacral Schwannoma

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    Sacral schwannoma is a rare tumor with relatively few symptoms; it thus tends to be large at diagnosis and is challenging to treat surgically. We present the case of a 12-year-old girl with a large sacral schwannoma that was successfully surgically resected using O-arm navigation in a two-stage operation. First, we performed tumor resection from the posterior aspect with assisted O-arm navigation. One week later, resection from the anterior aspect was conducted with posterior spinopelvic fixation and fibula graft. We performed partial resection of the tumor from the anterior and posterior aspects as much as possible. O-arm navigation contributed to precise and safe tumor resection and implant insertion
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