502 research outputs found
The Underreaction Hypothesis and the New Issue Puzzle: Evidence from Japan
This paper investigates the long-term performance of Japanese firms issuing convertible debt or equity. We find that these firms perform poorly even though the stock-price reaction to convertible debt and equity issue announcements is not significantly negative for Japanese firms and Japanese firms do not issue equity or convertible debt following strong positive abnormal returns. Whereas in the U.S. underperformance appears to be concentrated in the smaller firms and in the firms with a high market-to-book ratio, this is not the case in Japan. The underperformance of Japanese issuing firms cannot be understood in terms of the underreaction hypothesis that some have advanced as an explanation for the poor returns of U.S. issuing firms.
CVD-grown monolayer MoS2 in bioabsorbable electronics and biosensors
Transient electronics entails the capability of electronic components to dissolve or reabsorb in a controlled manner when used in biomedical implants. Here, the authors perform a systematic study of the processes of hydrolysis, bioabsorption, cytotoxicity and immunological biocompatibility of monolayer MoS2
Systemic chemotherapy for treatment of advanced small bowel adenocarcinoma with prognostic factor analysis: retrospective study
<p>Abstract</p> <p>Background</p> <p>We sought to evaluate prognostic factors affecting overall survival (OS), and to investigate the role of palliative chemotherapy using propensity score-based weighting, in patients with advanced small bowel adenocarcinoma (SBA).</p> <p>Methods</p> <p>Data from a total of 91 patients diagnosed with advanced SBA at the Asan Medical Center between January 1989 and December 2009 were retrospectively analyzed. Patients were split into two groups, those who did and did not receive palliative chemotherapy.</p> <p>Results</p> <p>Overall, 81 patients (89.0%) died, at a median survival time of 6.6 months (95% confidence interval [CI], 5.5 - 7.5 months). The 40 patients receiving chemotherapy showed overall response and disease control rates of 11.1% and 37.0%, respectively, with OS and progression-free survival (PFS) of 11.8 months (95% CI, 4.6 - 19.0 months) and 5.7 months (95% CI, 3.5 - 8.0 months), respectively. The 41 patients who did not receive chemotherapy had an OS of 4.1 months (95% CI, 3.1 - 5.1 months) and a PFS of 1.3 months (95% CI, 0.8 - 1.7 months). Multivariate analysis showed that lack of tumor resection, non-prescription of chemotherapy, liver metastasis, and intra-abdominal lymph node metastasis, were all independently associated with poor survival outcomes. After inverse probability of treatment weighting (IPTW) adjustment, the group that did not receive chemotherapy was at a significantly higher risk of mortality (HR 3.44, 95% CI 2.03 - 5.83, p < 0.001) than were patients receiving chemotherapy.</p> <p>Conclusion</p> <p>Palliative chemotherapy may improve survival outcomes in patients with advanced SBA.</p
Microspinning: Local Surface Mixing via Rotation of Magnetic Microparticles for Efficient Small-Volume Bioassays
The need for high-throughput screening has led to the miniaturization of the reaction volume of the chamber in bioassays. As the reactor gets smaller, surface tension dominates the gravitational or inertial force, and mixing efficiency decreases in small-scale reactions. Because passive mixing by simple diffusion in tens of microliter-scale volumes takes a long time, active mixing is needed. Here, we report an efficient micromixing method using magnetically rotating microparticles with patterned magnetization induced by magnetic nanoparticle chains. Because the microparticles have magnetization patterning due to fabrication with magnetic nanoparticle chains, the microparticles can rotate along the external rotating magnetic field, causing micromixing. We validated the reaction efficiency by comparing this micromixing method with other mixing methods such as simple diffusion and the use of a rocking shaker at various working volumes. This method has the potential to be widely utilized in suspension assay technology as an efficient mixing strategy
The Effects of Changing from Isoflurane to Desflurane on the Recovery Profile during the Latter Part of Anesthesia
It is not known whether changing from isoflurane to desflurane during the latter part of anesthesia shows early emergence and recovery in long surgery. We therefore evaluated the effects of changing isoflurane to desflurane on emergence and recovery. Eighty-two patients were randomly assigned to receive isoflurane (Group I) or desflurane (Group D) or to change from isoflurane to desflurane anesthesia (Group X). At the point when there was an hour until the operation would end, isoflurane was replaced with 1 MAC of desflurane in Group X, and isoflurane and desflurane were maintained at 1 MAC in Groups I and D. When the operation ended, we compared the emergence and recovery characteristics among the 3 groups. Compared with Group I, Group X showed faster emergence and recovery. Group X and Group D showed similar emergence and recovery. In conclusion, changing isoflurane to desflurane during the latter part of anesthesia improves emergence and recovery
Fate of untreated asymptomatic osteonecrosis of the femoral head
BACKGROUND: Magnetic resonance imaging has made it possible to detect asymptomatic lesions of osteonecrosis of the femoral head before abnormalities appear on plain radiographs. The extent of a necrotic lesion is known to be an important prognostic factor. In this study, we evaluated the fate of untreated asymptomatic osteonecrosis of the femoral head with an emphasis on the size of the lesion. We hypothesized that a lesion smaller than a certain size would not progress to symptomatic disease. METHODS: One hundred and five initially asymptomatic hips of patients with bilateral nontraumatic osteonecrosis of the femoral head who had been followed without any treatment for at least five years or until pain developed were enrolled in this study. The extent of a lesion was estimated according to the area of the lesion based on a two-dimensional analysis on magnetic resonance images or on plain radiographs at the time of diagnosis. RESULTS: Sixty-two hips became symptomatic, and forty-three hips remained asymptomatic for more than five years (average, eight years and seven months). Of the twenty-one hips with a small necrotic lesion (50% of the area of the femoral head), fifty became painful. Forty-six of the sixty-two hips that became symptomatic required surgery. Pain developed within five years after the diagnosis in fifty-eight (94%) of the sixty-two symptomatic hips. CONCLUSIONS: No treatment appears to be necessary for asymptomatic necrotic lesions with an area smaller than 30% of the femoral head, as the vast majority of these lesions will remain asymptomatic for more than five years
Alumina-on-Alumina Total Hip Arthroplasty A Concise Follow-up, at a Minimum of Ten Years, of a Previous Report
We previously reported the five-to-six-year results of the use of third-generation alumina-on-alumina bearings in a consecutive series of 100 primary cementless total hip arthroplasties. This report presents the longer-term outcomes of these same bearings, at a minimum of ten years postoperatively. Eighty-six of eighty-eight hips available for the study retained the original bearings at the time of the latest follow-up. Thirteen hips were associated with noise, and six hips demonstrated fretting of the femoral neck on radiographs. Two hips required a change of the bearings because of a ceramic head fracture. The ten-year survival rate of the alumina-on-alumina total hip prostheses, with revision of any implant for any reason as the end point, was 99.0%. On the basis of those results, we concluded that the rate of survival of primary cementless total hip prostheses with third-generation alumina-on-alumina bearings is excellent at ten years. However, the risk of ceramic fracture, noise, and impingement between the metal neck and the ceramic liner should be a concern to surgeons, and patients should be informed of these risks before surgery.Koo KH, 2008, J BONE JOINT SURG AM, V90A, P329, DOI 10.2106/JBJS.F.01489Sugano N, 2007, J BONE JOINT SURG BR, V89B, P455Yoo JJ, 2005, J BONE JOINT SURG AM, V87A, P530, DOI 10.2106/JBJS.D01753Allain J, 1998, J BONE JOINT SURG AM, V80A, P1355Joshi RP, 1998, J BONE JOINT SURG BR, V80B, P585MARTELL JM, 1993, J BONE JOINT SURG AM, V75A, P554MALONEY WJ, 1990, J BONE JOINT SURG AM, V72A, P1025BELLAMY N, 1988, J RHEUMATOL, V15, P1833ENGH CA, 1987, J BONE JOINT SURG BR, V69, P45SARMIENTO A, 1985, J BONE JOINT SURG AM, V67A, P48GRUEN TA, 1979, CLIN ORTHOP RELAT R, P17DELEE JG, 1976, CLIN ORTHOP RELAT R, P20HARRIS WH, 1969, J BONE JOINT SURG AM, VA 51, P737KAPLAN EL, 1958, J AM STAT ASSOC, V53, P457
Spontaneous pneumothorax during laparoscopy-assisted Billroth-I gastrectomy -A case report-
Pneumothorax associated with a pneumoperitonium in laparoscopic surgery is rare but can cause life-threatening complications. A 62-year-old man was scheduled for a laparoscopy-assisted Billroth-I gastrectomy under general anesthesia. Approximately 70 minutes after insufflating carbon dioxide into the intraabdominal cavity at a pressure of 12 mmHg, the peak inspiratory pressure increased, while the oxygen saturation decreased. The pneumothorax of the left lung was evident on the intraoperative chest radiograph. The pneumothorax improved after inserting a catheter into the affected area. The cause of the pneumothorax was unknown but an anatomical defect is believed responsible. This report shows that pneumothorax developed under an intraabdominal pressure in the conventional safety range. Careful monitoring and immediate treatment is necessary to prevent the condition from worsening
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Cell Labeling and Tracking Method without Distorted Signals by Phagocytosis of Macrophages
Cell labeling and tracking are important processes in understanding biologic mechanisms and the therapeutic effect of inoculated cells in vivo. Numerous attempts have been made to label and track inoculated cells in vivo; however, these methods have limitations as a result of their biological effects, including secondary phagocytosis of macrophages and genetic modification. Here, we investigated a new cell labeling and tracking strategy based on metabolic glycoengineering and bioorthogonal click chemistry. We first treated cells with tetra-acetylated N-azidoacetyl-D-mannosamine to generate unnatural sialic acids with azide groups on the surface of the target cells. The azide-labeled cells were then transplanted to mouse liver, and dibenzyl cyclooctyne-conjugated Cy5 (DBCO-Cy5) was intravenously injected into mice to chemically bind with the azide groups on the surface of the target cells in vivo for target cell visualization. Unnatural sialic acids with azide groups could be artificially induced on the surface of target cells by glycoengineering. We then tracked the azide groups on the surface of the cells by DBCO-Cy5 in vivo using bioorthogonal click chemistry. Importantly, labeling efficacy was enhanced and false signals by phagocytosis of macrophages were reduced. This strategy will be highly useful for cell labeling and tracking
Brief Education on Microvasculature and Pit Pattern for Trainees Significantly Improves Estimation of the Invasion Depth of Colorectal Tumors
Objectives. This study was performed to evaluate the effectiveness of education for trainees on the gross findings identified by conventional white-light endoscopy (CWE), the microvascular patterns identified by magnifying narrow-band imaging endoscopy (MNE), and the pit patterns identified by magnifying chromoendoscopy (MCE) in estimation of the invasion depth of colorectal tumors. Methods. A total of 420 endoscopic images of 35 colorectal tumors were used. Five trainees estimated the invasion depth of the tumors by reviewing the CWE images before education. Afterwards, the trainees estimated the invasion depth of the same tumors after brief education on CWE, MNE and MCE images, respectively. Results. The initial diagnostic accuracy for deep submucosal invasion before education and after education on CWE, MNE, and MCE findings was 54.3%, 55.4%, 67.4%, and 76.6%, respectively. The diagnostic accuracy increased significantly after MNE education (P=0.028). The specificity for deep submucosal invasion before education and after education on CWE, MNE, and MCE findings was 47.9%, 45.7%, 65.0%, and 80.7%, respectively. The specificity increased significantly after MNE (P=0.002) and MCE (P=0.005) education. Conclusion. Brief education on microvascular pattern identification by MNE and pit pattern identification by MCE significantly improves trainees’ estimations of the invasion depth of colorectal tumors
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