4,969 research outputs found
Optimizing radiation dose and fractionation for the definitive treatment of locally advanced non-small cell lung cancer
Severe impacted valgus proximal humerus fractures : results of operative treatment
Background: The functional results associated with nonoperative treatment of severely impacted valgus fractures of the proximal part of the humerus are poor, and these injuries are difficult to treat with minimally invasive percutaneous fixation techniques. The aim of this study was to review the functional and radiographic results and complications of a new operative technique in a series of twenty-five patients.Methods: Over a two-year period, we treated twenty-nine patients with a severely impacted valgus fracture of the proximal part of the humerus. Three patients were lost to follow-up and one died, leaving twenty-five patients who were available for the study. In all of the fractures, the head-shaft angle had been tilted into =160° of valgus and the greater tuberosity was displaced by >1 cm. All patients were treated with open reduction of the fracture, and the space created behind the humeral head was filled with Norian Skeletal Repair System (SRS) bone substitute. The fractures were stabilized with either screws or buttress plate fixation. Associated rotator cuff tears were repaired. All patients underwent functional outcome assessment with use of the Constant, DASH (Disabilities of the Arm, Shoulder and Hand), and SF-36 (Short Form-36) scores at one year, and twelve patients were followed for two years.Results: All fractures united within the first year, all reductions were maintained, and no patient had signs of osteonecrosis of the humeral head on the latest follow-up radiographs. At one year, the median Constant score was 80 points and the median DASH score was 22 points. The functional results continued to be satisfactory in the twelve patients who were followed for two years. The results in our series were better than those achieved in studies of nonoperative treatment of similar fracture configurations. There were six clinically relevant complications, although none required a reoperation and all six patients had a satisfactory short-term functional outcome.Conclusions: Internal fixation of severely impacted valgus fractures of the proximal part of the humerus, supplemented by Norian SRS bone substitute to fill the proximal humeral metaphyseal defect, produces good early functional and radiographic outcomes. Additional follow-up will be required to assess whether these initially satisfactory outcomes are maintained over the longer term.Level of Evidence: Therapeutic study, Level IV (case series [no, or historical, control group]). See Instructions to Authors for a complete description of levels of evidence.<br /
Severely impacted valgus proximal humeral fractures : surgical technique
Background: The functional results associated with nonoperative treatment of severely impacted valgus fractures of the proximal part of the humerus are poor, and these injuries are difficult to treat with minimally invasive percutaneous fixation techniques. The aim of this study was to review the functional and radiographic results and complications of a new operative technique in a series of twenty-five patients.Methods: Over a two-year period, we treated twenty-nine patients with a severely impacted valgus fracture of the proximal part of the humerus. Three patients were lost to follow-up and one died, leaving twenty-five patients who were available for the study. In all of the fractures, the head-shaft angle had been tilted into > or = 160 degrees of valgus and the greater tuberosity was displaced by >1 cm. All patients were treated with open reduction of the fracture, and the space created behind the humeral head was filled with Norian Skeletal Repair System (SRS) bone substitute. The fractures were stabilized with either screws or buttress plate fixation. Associated rotator cuff tears were repaired. All patients underwent functional outcome assessment with use of the Constant, DASH (Disabilities of the Arm, Shoulder and Hand), and SF-36 (Short Form-36) scores at one year, and twelve patients were followed for two years.Results: All fractures united within the first year, all reductions were maintained, and no patient had signs of osteonecrosis of the humeral head on the latest follow-up radiographs. At one year, the median Constant score was 80 points and the median DASH score was 22 points. The functional results continued to be satisfactory in the twelve patients who were followed for two years. The results in our series were better than those achieved in studies of nonoperative treatment of similar fracture configurations. There were six clinically relevant complications, although none required a reoperation and all six patients had a satisfactory short-term functional outcome.Conclusions: Internal fixation of severely impacted valgus fractures of the proximal part of the humerus, supplemented by Norian SRS bone substitute to fill the proximal humeral metaphyseal defect, produces good early functional and radiographic outcomes. Additional follow-up will be required to assess whether these initially satisfactory outcomes are maintained over the longer term.<br /
Hot Corrosion Test Facility at the NASA Lewis Special Projects Laboratory
The Hot Corrosion Test Facility (HCTF) at the NASA Lewis Special Projects Laboratory (SPL) is a high-velocity, pressurized burner rig currently used to evaluate the environmental durability of advanced ceramic materials such as SiC and Si3N4. The HCTF uses laboratory service air which is preheated, mixed with jet fuel, and ignited to simulate the conditions of a gas turbine engine. Air, fuel, and water systems are computer-controlled to maintain test conditions which include maximum air flows of 250 kg/hr (550 lbm/hr), pressures of 100-600 kPa (1-6 atm), and gas temperatures exceeding 1500 C (2732 F). The HCTF provides a relatively inexpensive, yet sophisticated means for researchers to study the high-temperature oxidation of advanced materials, and the injection of a salt solution provides the added capability of conducting hot corrosion studies
The influence of altitude on the anaerobic and aerobic capacities of men in work Final scientific report
Altitude influence on anaerobic and aerobic capacities of working me
Teacher Absenteeism: Its Relationship to Student Performance on State Assessments in English/Language Arts in Grades Three, Five, and Seven
The topic for the study is teacher absenteeism. The literature review included a discussion of the importance of the study, the research base on teacher attendance and student performance, patterns and trends in teacher absenteeism, cost implications for teacher absenteeism, impact of teachers\u27 absenteeism on student performance and school operations, impact on urban schools, and intervention strategies to reduce absenteeism or mitigate the negative impact when teacher absences do occur. The hypothesis of the study is that there is a significant negative relationship between the extent, the reason for, or the pattern of teachers being absent from the classroom and the performance of the students they teach on state assessments in English/language arts. The study was conducted in a medium-size urban school district in upstate New York. The performance of 7030 students on the English/language arts State assessment was correlated to the absences of 672 teachers assigned to teach English/language arts to those students. All student performance data and teacher absence data was for the 2006-2007 school year. Pearson correlations were used and significance was determined at the p=0.05 level. The results of the study quite unequivocally show that teacher absences are unrelated to student performance on the State English/language arts tests and certainly are not a negative relationship. That is, students do not perform lower when teacher absenteeism is higher. There are some weak relationships at grades five and seven that are significant, but these relationships show a positive relationship between teacher absenteeism and student performance. That is, the scores are higher when teachers are absent more. These results are counterintuitive and generate a number of questions. There is a critical and dramatic overriding question that is generated by the results of this study. To what extent is the presence of the teacher responsible for student performance? Recommendations for future research or actions based on the results are discussed. Recommendations for changes in organizational procedures or practices, professional practice, and approaches for program improvement are explored
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