Microstructure control of multi-layered EBC prepared by dual electron beam PVD

Environmental barrier coatings (EBCs) can play important roles in enabling SiC fiber reinforced SiC matrix composites (SiC/SiC) for application to advanced hot-section components in airplane engines. EBCs must exhibit superior environmental shielding durability and excellent volatilization resistance in the combustion environment containing water vapor. Therefore, a multilayered structure is applied when designing EBCs. Yb silicates are promising substances for EBC use. Volatilization resistance of Yb2SiO5 is superior to Yb2Si2O7. Thermal expansion coefficient of Yb2Si2O7 is closer to SiC/SiC composites than Yb2SiO5 and it exhibits a single phase up to about 1873 K. Mullite has higher oxygen shielding performance than Yb2Si2O7. Thus, we design EBC which is composed of a bond layer, dense mullite oxygen shielding layer, compositional-gradient dense Yb silicate layer showing water vapor shielding function, and Yb2SiO5 layer with segmented structure. The function of the Yb2SiO5 layer is reduction of thermal stresses during thermal cycling. Such an environmental shielding capability depends greatly on both the compositions and microstructures of the layers. Therefore, the coating processes used to make the EBCs should allow precise control of these factors. While it is difficult to strictly control the compositions of such complex oxides using conventional plasma spray deposition techniques due to incongruent evaporation of raw powders, dual electron beam physical vapor deposition (EB-PVD) is a potential process for constructing the complex oxides layer with controlled compositions as well as microstructures. We recently reported that formation of Yb2Si2O7 layer by dual EB-PVD [1]. In the present study, we investigated the in-situ formation of a dense mullite layer, compositional gradient layer from Yb2Si2O7 to Yb2SiO5 with dense structure, and Yb2SiO5 layer with segmented structure via dual EB-PVD, simultaneously heating the substrate. Please click Additional Files below to see the full abstract

Remodeling of Monoplanar Purkinje Cell Dendrites during Cerebellar Circuit Formation

Dendrite arborization patterns are critical determinants of neuronal connectivity and integration. Planar and highly branched dendrites of the cerebellar Purkinje cell receive specific topographical projections from two major afferent pathways; a single climbing fiber axon from the inferior olive that extend along Purkinje dendrites, and parallel fiber axons of granule cells that contact vertically to the plane of dendrites. It has been believed that murine Purkinje cell dendrites extend in a single parasagittal plane in the molecular layer after the cell polarity is determined during the early postnatal development. By three-dimensional confocal analysis of growing Purkinje cells, we observed that mouse Purkinje cells underwent dynamic dendritic remodeling during circuit maturation in the third postnatal week. After dendrites were polarized and flattened in the early second postnatal week, dendritic arbors gradually expanded in multiple sagittal planes in the molecular layer by intensive growth and branching by the third postnatal week. Dendrites then became confined to a single plane in the fourth postnatal week. Multiplanar Purkinje cells in the third week were often associated by ectopic climbing fibers innervating nearby Purkinje cells in distinct sagittal planes. The mature monoplanar arborization was disrupted in mutant mice with abnormal Purkinje cell connectivity and motor discoordination. The dendrite remodeling was also impaired by pharmacological disruption of normal afferent activity during the second or third postnatal week. Our results suggest that the monoplanar arborization of Purkinje cells is coupled with functional development of the cerebellar circuitry

Optimal Entry Point for Lateral Mass Screwing

Study Design: Retrospective study of 37 consecutive female patients with cervical spondylotic myelopathy who underwent reconstructed computed tomography (CT) scanning of the cervical spine. Purpose: The purpose of this study was to investigate whether the vertebral lateral notch of the cervical spine is an effective landmark to determine the entry point for lateral mass screwing. A modified Roy-Camille technique was used to determine the entry point associated with the lateral notch of the cervical spine. Overview of Literature: The Roy-Camille technique has been a popular technique for the posterior fixation of the cervical spine. A problem with this technique is determining the entry point on the lateral mass via visual inspection, such as in cases with degenerative or destructive cervical facet joints. Methods: Thirty-three female patients with cervical spondylotic myelopathy underwent reconstructed CT scanning of the cervical spine. Overall, 132 vertebrae from C3 to C6 were reviewed using reconstructed CT. The probable trajectory using a modified Roy-Camille technique was determined using reconstructed CT scans, and the optimal entry point was identified. Horizontal and vertical distances from the vertebral lateral notch were measured. Results: The entry point determined using the modified Roy-Camille technique was significantly superior and medial compared with that determined using the conventional Roy-Camille technique. At C3 and C4 levels, the entry point using the modified technique was 1.4 mm below and 4.4 mm medial to the lateral notch, and at C5 and C6 levels, it was 2.3 mm below and 4.9 mm medial to the lateral notch. Conclusions: The vertebral lateral notch of the cervical spine was an effective landmark to determine the entry point for lateral mass screwing. The modified Roy-Camille technique proposed here may prevent surgical complications and poor outcomes

Primary placement technique of jejunostomy using the entristar™ skin-level gastrostomy tube in patients with esophageal cancer

<p>Abstract</p> <p>Background</p> <p>We developed a skin-level jejunostomy tube (SLJT) procedure for patients undergoing esophagectomy using a skin-level gastrostomy tube (G-tube) (Entristar™; Tyco Healthcare, Mansfield, Mass), in order to improve their nutrition status and quality of life (QOL). We describe the procedure and the adverse effects of SLJT in patients with esophageal cancer (EC).</p> <p>Methods</p> <p>Over a 24-month period (March 2008 to March 2010), there were 16 patients (mean age: 61.8 years; age range: 49-75 years; 15 men, 1 woman) who had Stage II or III EC. Primary jejunostomy was performed under general anesthesia during esophagectomy. The technical success and the immediate and delayed complications of the procedure were recorded.</p> <p>Jejunostomy techniques</p> <p>SLJT placement using the G-tube (20Fr) was performed 20 cm from the Treitz ligament on the side opposing the jejunal mesenterium. The internal retention bolster was exteriorized through an incision in the abdominal wall. A single purse string suture using a 4-0 absorbable suture was performed. The internal retention bolster was then inserted into the jejunal lumen via the small incision. The intestine adjacent to the tube was anchored to the peritoneum using a single stitch.</p> <p>Results</p> <p>The SLJT was successfully inserted in all 16 patients. No early complications were documented. Follow-up for a median of 107 days (range, 26-320 days) revealed leakage to the skin in four patients, including superficial wound infections in two patients. There were no cases of obstruction of the tube or procedure-related death.</p> <p>Conclusions</p> <p>This SLJT placement technique using the G-tube is a safe procedure in patients with EC and allows the creation of a long-term feeding jejunostomy.</p

Vertebral Lateral Notch as Optimal Entry Point for Lateral Mass Screwing Using Modified Roy-Camille Technique

Study DesignRetrospective study of 37 consecutive female patients with cervical spondylotic myelopathy who underwent reconstructed computed tomography (CT) scanning of the cervical spine.PurposeThe purpose of this study was to investigate whether the vertebral lateral notch of the cervical spine is an effective landmark to determine the entry point for lateral mass screwing. A modified Roy-Camille technique was used to determine the entry point associated with the lateral notch of the cervical spine.Overview of LiteratureThe Roy-Camille technique has been a popular technique for the posterior fixation of the cervical spine. A problem with this technique is determining the entry point on the lateral mass via visual inspection, such as in cases with degenerative or destructive cervical facet joints.MethodsThirty-three female patients with cervical spondylotic myelopathy underwent reconstructed CT scanning of the cervical spine. Overall, 132 vertebrae from C3 to C6 were reviewed using reconstructed CT. The probable trajectory using a modified Roy-Camille technique was determined using reconstructed CT scans, and the optimal entry point was identified. Horizontal and vertical distances from the vertebral lateral notch were measured.ResultsThe entry point determined using the modified Roy-Camille technique was significantly superior and medial compared with that determined using the conventional Roy-Camille technique. At C3 and C4 levels, the entry point using the modified technique was 1.4 mm below and 4.4 mm medial to the lateral notch, and at C5 and C6 levels, it was 2.3 mm below and 4.9 mm medial to the lateral notch.ConclusionsThe vertebral lateral notch of the cervical spine was an effective landmark to determine the entry point for lateral mass screwing. The modified Roy-Camille technique proposed here may prevent surgical complications and poor outcomes

Ⅰ型アレルギー反応および副腎皮質ホルモンは気管支喘息における末梢血白血球のロイコトリエンB4およびC4産生に影響をおよぼす

The generation. of leukotrienes 84 (LT84) and C4 (LTC4) by leucocytes stimulated with Ca ionophore A23187 was examined in 71 patients with asthma (42 with atopic and 29 with nonatopic asthma) and 23 healthy controls. Of these patients,22 had SDIA (steroid-dependent intractable asthma). 1. The generation of LT84 and LTC4 by leucocytes was significantly more enhanced in patients with atopic, non-SOIA asthma than in healthy subjects, but not in patients with nonatopic asthma. The generation of LT84 and LTC4 in atopic asthma was significantly more decreased in patients with SOIA than in those with non-SOIA. 2. The LTC4 generation was significantly larger in attack stage than in attack-free stage of patients with atopic and nonatopic asthma when they had not SOIA. However, no significant difference was found in LT84 generation between attack and nonattack stages in these patients. 3. In patients with SOIA, no significant differences were observed in the generation of LT84 and LTC4 between attack and nonattack stages. The results suggest that IgE-mediated allergy and asthma attacks enhance and glucocorticoids inhibit the generation of LT84 and LTC4 by leucocytes.気管支喘息71例および健康人23名を対象に､Ca ionophore A23187刺激時の末梢血白血球のロイコトリエンB4 (LTB4)およびC4(LTC4)の産生能について検討を加えた｡なお､71例中ステロイド依存性重症難治性喘息(SDIA)は22例であった。1.アトピー性､16非SDIA症例におけるLTB4､LTC4産生は､健康人と比べ有意に高い値を示したが､非アトピー性喘息では健康人との間に有意の差は見られなかった｡また､アトピー性喘息では､SDIA症例において非SDIA症例に比べ､LTB4､LTC4産生が有意に抑制されていた｡2.非SDIA症例では､アトピー性､非アトピー性を問わず､LTC4産生は､非発作時に比べ発作時に有意に亢進した状態であった｡しかし､LTB4産生には､非発作時､発作時との間に有意の差は見られなかった｡3.SDIA症例では､LTB4､LTC4産生と発作との有意の関連は見られなかった｡以上の結果より､IgE にmediateされるアレルギー反応や喘息発作はLTB4､LTC4産生に促進的に､また副腎皮質ホルモンは抑制的に作用することが示唆された

Activity of bone morphogenetic protein-7 after treatment at various temperatures: Freezing vs. pasteurization vs. allograft

Insufficient bone union is the occasional complication of biomechanical reconstruction after malignant bone tumor resection using temperature treated tumor bearing bone; freezing, pasteurization, and autoclaving. Since bone morphogenetic protein (BMP) plays an important role in bone formation, we assessed the amount and activity of BMP preserved after several temperature treatments, including -196 and -73 °C for 20 min, 60 and 100 °C for 30 min, 60 °C for 10 h following -80 °C for 12 h as an allograft model, and 4 °C as the control. The material extracted from the human femoral bone was treated, and the amount of BMP-7 was analyzed using an enzyme-linked immunosorbent assay. Then, the activity of recombinant human BMP-7 after the treatment was assessed using a bioassay with NIH3T3 cells and immunoblotting analysis to measure the amount of phospho-Smad, one of the signaling substrates that reflect the intracellular reaction of BMPs. Both experiments revealed that BMP-7 was significantly better preserved in the hypothermia groups. The percentages of the amount of BMP-7 in which the control group was set at 100% were 114%, 108%, 70%, 49%, and 53% in the -196, -73, 60, 100 °C, and the allograft-model group, respectively. The percentages of the amount of phospho-Smad were 89%, 87%, 24%, 4.9%, and 14% in the -196, -73, 60, 100 °C, and the allograft-model group, respectively. These results suggested that freezing possibly preserves osteoinductive ability than hyperthermia treatment. © 2011 Elsevier Inc. All rights reserved