Prevalence of and risk factors for postoperative complications after lower third molar extraction : A multicenter prospective observational study in Japan

Lower third molar extraction is the most common surgical treatment among routine dental and oral surgical procedures. while the surgical procedures for lower third molar extraction are well established, the difficulty of tooth extraction and the frequency of postoperative complications differ depending on the patient’s background. To establish a management protocol for the lower third molars, the prevalence of and risk factors for postoperative complications after lower third molar extraction were investigated in a large number of Japanese patients in a multicenter prospective study. During 6 consecutive months in 2020, 1826 lower third molar extractions were performed at the 20 participating institutions. The medical records of the patients were reviewed, and relevant data were extracted. The prevalence of and risk factors for postoperative complications were analyzed. The prevalence of postoperative complications after lower third molar extraction was 10.0%. Multivariate analysis indicated that age (≤32 vs >32, odds ratio [OR]: 1.428, 95% confidence interval [95% CI]: 1.040–1.962, P < .05), the radiographic anatomical relationship between the tooth roots and mandibular canal (overlapping of the roots and canal vs no close anatomical relationship between the roots and the superior border of the canal, OR: 2.078, 95% CI: 1.333–3.238, P < .01; overlapping of the roots and canal vs roots impinging on the superior border of the canal, OR: 1.599, 95% CI: 1.050–2.435, P < .05), and impaction depth according to the Pell and Gregory classification (position C vs position A, OR: 3.7622, 95% CI: 2.079–6.310, P < .001; position C vs position B, OR: 2.574, 95% CI: 1.574–4.210, P < .001) are significant independent risk factors for postoperative complications after lower third molar extraction. These results suggested that higher age and a deeply impacted tooth might be significant independent risk factors for postoperative complications after lower third molar extraction

Field experiments in labor economics

In this thesis I show with three studies how field experiments can enhance our understanding of labor markets. Economists traditionally assume that individuals exclusively respond to monetary incentives. As a consequence, if workers have no prospect of future employment at the firm and pay is not contingent on their performance, a wage change should not affect effort. Some economists, however, have recognized that this narrow view of human motivation may severely limit our progress in understanding incentives. In Chapters 2 and 3, I investigate the role of psychological motives like the desire to reciprocate in the context of a real‐life work environment. The first experiment explores the impact of a wage increase on work performance when there is no economic reason for workers to change their effort. I find that workers reciprocate a generous wage with higher performance, particularly those workers who care about fairness and felt underpaid prior to the wage increase. The second experiment investigates the effects of a wage cut on performance when either all workers in a team or only some of them suffer the cut. I show that a general pay cut reduces performance, while a wage cut for only some of the workers reduces their performance more than twice as much. This finding demonstrates the powerful force of social comparison and the need to build the social nature of humans into economic theory. In Chapter 4, I examine the joint effects of monetary incentives and social interaction on work performance. Many jobs offer wage schemes that create positive or negative externalities on coworkers. Whether or not workers have the possibility to interact socially at work may distort the intended incentives of these schemes. I find that under relative incentives, when own effort imposes a negative externality on the coworker’s income, social interaction works against monetary incentives and leads to low performance due to collusion. However, the more workers differ in skills the less able they are to sustain collusive agreements. In der vorliegenden Dissertation zeige ich anhand von drei Studien wie Feldexperimente unser Verständnis von Arbeitsmärkten verbessern können. Ökonomen gehen traditionell davon aus, dass Individuen ausschliesslich auf materielle Anreize reagieren. Wenn also Arbeitskräfte keine Aussicht auf eine langfristige Anstellung haben und deren Lohn nicht von der Leistung abhängt, dann sollte eine Lohnveränderung keinen Einfluss auf die Arbeitsleistung haben. Manche Ökonomen haben jedoch erkannt, dass diese Sichtweise des menschlichen Verhaltens beschränkt ist und unseren Fortschritt im Verständnis von Anreizen bremsen kann. In den Kapiteln 2 und 3 untersuche ich die Bedeutung von psychologischen Motiven wie Fairness oder Reziprozität in echten Arbeitsumgebungen. Das erste Experiment untersucht den Einfluss einer Lohnerhöhung auf die Arbeitsleistung, wenn Arbeitskräfte keinen ökonomischen Grund haben, ihren Arbeitseinsatz zu ändern. Diese Studie zeigt, dass Arbeitskräfte einen grosszügigen Lohn mit höherer Arbeitsleistung erwidern. Dies gilt besonders für diejenigen, die Fairness als wichtig empfinden und sich vor der Lohnerhöhung unterbezahlt fühlten. Das zweite Experiment untersucht die Wirkung einer Lohnkürzung auf die Arbeitsleistung, wenn entweder das ganze Team oder nur einen Teil davon betroffen ist. Diese Studie zeigt auf, dass eine generelle Lohnkürzung die Arbeitsleistung senkt, wohingegen eine Lohnkürzung nur für einzelne Arbeitskräfte deren Leistung um mehr als das Doppelte reduziert. Diese Erkenntnis unterstreicht die Bedeutung von sozialen Motiven und die Notwendigkeit einer Veränderung des Menschenbilds in der Ökonomie. In Kapitel 4 erforsche ich den gemeinsamen Einfluss von materiellen Anreizen und sozialer Interaktion auf die Arbeitsleistung. Viele Firmen bieten Lohnsysteme an, bei welchen die eigene Leistung vor‐ oder nachteilhafte Nebeneffekte auf das Einkommen der Arbeitskollegen hat. Soziale Interaktion am Arbeitsplatz kann dabei die Anreize dieser Lohnsysteme verzerren. Diese Studie findet heraus, dass bei Entlohnung der Arbeitskräfte durch Turnieranreize, d.h. wenn die eigene Leistung sich nachteilhaft auf das Einkommen der Arbeitskollegen auswirkt, soziale Interaktion die Anreize ausser Kraft setzt und zu geheimen Absprachen führt. Wenn hingegen Arbeitskräfte sehr unterschiedliche Fähigkeiten besitzen, dann sind geheime Absprachen schwieriger aufrecht zu halten

Carbon ion radiotherapy in hypofraction regimen for stage I non-small cell lung cancer

Background. Carbon ion radiotherapy is a promising modality because of its excellent dose localization and high biological effects on a tumor. In the present study, fixing the total dose was fixed at 72 GyE in 9 fractions over 3 weeks, and at 52.8 GyE for stage 1A and at 60 GyE for stage 1B over one week, Using these fractionation schedules, we conducted a phase 2 clinical trial for stage NSCLC from 1999 to 2003 determine the local control and the survival rates.Methods. One hundred twenty nine patients with 133 primary lesions were treated. The average age of the patients was 74.5 years. The patient population consisted of, 92 males and 37 females. The T1 and T2 numbers were 72 and 59, respectively. The average tumor size (diameter) was 31.5mm. By type, the tumors broke down into 85 adenocarcinomas, 43 squamous cell carcinomas, two large cell carcinomas and one adenosquamous cell carcinopma. A primary tumor was treated with carbon beam alone using the fixed total dose of 72 GyE in 9 fractions over 3 weeks, and 52.8 GyE for stage 1A and 60 GyE for stage 1B over one week. Most of targets were irradiated from obliquely from four directions. A respiratory-gated irradiation system was used for irradiation in each case. Local control and survival were determined by using the Kaplan-Meyer method and the data were statistically processed by using the long-rank test.Results. The local control rate for all patients was 95.2%. There was no statistical difference in the local control rate between T1 and T2 (p=0.063), and between the squamous and non-squamous type (p=0.208). The patients five-year cause-specific survival rate of them was 79.1% (IA: 90.3, IB: 63.2), and overall survival was 57.3% (IA: 63.1, IB: 50). No toxic reactions were observed in the skin and no adverse effects worse than grade 3 were detected. Conclusions. Carbon beam radiotherapy, a new therapy modality with superior benefits in terms of QOL and ADL, has been proven to be a valid alternative to surgery for stage I and to offer particular benefits especially for elderly and inoperable patients.11th Ｗｏｒｌｄ Ｃｏｎｇｒｅｓｓ ｏｎ Advances in Oncology and 9th International Symposium on Molecular Medicin

Single-dose carbon beam radiotherapy (carbon beam radiosurgery) for stage I non-small cell lung cancer.

日独放射線医学交流計画第１２回ワークショッ

Carbon ion radiotherapy in hypofraction and ultrahypofraction regimens for stage I non-small cell lung cancer

11th World Conference on Lung Cance

Establishing Design Values for Potential Utilization of Western Juniper as a Building Material

Western juniper (Juniperus occidentalis) is a conifer that is native to Oregon, California, Washington, Nevada, and Idaho. Juniper is known to have highly decay resistant heartwood and is a popular choice for finished furniture. With recent forest management practices over the past 100 years have resulted in an immense population increase in western juniper stands, transforming the grasslands/sagebrush into juniper forests. Landowners have been encouraged to cutback western juniper to restore grassland habitat, but there is no major market associated with juniper. This study assessed the strength and durability properties of western juniper in order to develop design values in collaboration with the West Coast Lumber Inspection Bureau (WCLIB). The data will be presented to American Lumber Standard Committee (ALSC) for inclusion in the National Design Specification. Design values assigned to western juniper will allow contractors to use this species in structural and non-structural applications, especially for State funded projects. Samples were harvested from three locations in eastern Oregon, one location in northeast California, and one location in southwest Idaho. Tests were performed according to procedures described in ASTM Standard D143 small-clear specimens for compression, bending, and shear. Average strength values were calculated and compared to similar wood species. Most properties were similar to those of other species, but modulus of elasticity was significantly lower. The differences between species might be attributed to cell wall structure and distribution of lignin in the cells. Design values for western juniper were calculated using the strength values following the ASTM Standard D245 procedure for establishing structural grades and related allowable properties for visually graded lumber. Durability of western juniper was assessed using laboratory decay tests, marine tests, and ground contact exposure. The long term marine durability and ground contact tests are still on going. The laboratory decay test indicated that western juniper heartwood was highly resistant to attack by brown and white rot fungi.Keywords: Western Juniper, Design Value

INCORPORATING ORGAN MOTION UNCERTAINTIES INTO CARBON ION TREATMENT PLANNING

In the charged particle therapy of moving tumors in strongly inhomogeneous volume such as lung cancer and liver cancer, how to define the distal margins is not well established. We report and evaluate a method adopted in the treatment planning of lung cancer with respiration gated carbon ion broad beams at NIRS [1,2]. During treatment a patient is irradiated while the respiration signal from on-skin monitor is close to end expiration phase of free breathing. Planning CT scans are taken gated with the same signal. The internal margin to compensate for uncertainties in tumor respiration movements is defined as typically 5 mm in cranial-caudal (CC) direction. As a means to deliver beams to the distal end of PTV, we use the extended range compensator (RC). It is designed based on a model that (1) the lung including tumor moves in CC direction sliding along the chest wall; (2) its thickness is unchanged by the use of a thermoplastic immobilization mold.Dose distributions calculated for different tumor locations show dose coverage to CTV, whereas the irradiated lung volume increases in enhanced degree due to the low electron density of lung. The uncertainties in tumor motion are determined from clinical experiences including fluoroscopy observations. In order to reduce motion margins further, more accurate tumor position monitor is required. In this respect the study with 4D CT scanner recently installed will be helpful. [1] Kanai, T et al., (1999) Int J Radiat Oncol Bio Phys. 44:201-210. [2] Minohara, S et al., (2000) Int J Radiat Oncol Bio Phys. 47:1097-1103.Particle Therapy Co-Operative Group,PTCOG4