Status of the Mast experiment

Many sophisticated mathematical control techniques for flexible structures have been devised. The basic problem is that most of them require a relatively accurate mathematical model of the system under control including the dynamics of both the structure and the control system components. Obtaining such a model for either subsystem traditionally has required great effort including a significant validation step based on test data. Because of the quantum increase in complexity over proven methods, promising techniques for the control of flexible structures must be validated in actual hardware experiments before committing to their use in actual spacecraft missions. The Mast experiment system serves as a focus for such validation. It is the first in a series of experiments under the Control of Flexible Structures (COFS) Program at the NASA Langley Research Center. The Mast experiment is a combination of ground tests, orbital flight test, and analysis of a deployable beam under the COFS program. It provides a vehicle for research in structures, structural dynamics, and control issues

Comorbid illness is an important determinant of health-related quality of life in patients with chronic hepatitis C

Chronic hepatitis C (CHC) patients selected for entry into treatment trials have been reported to have impaired health-related quality of life (HRQOL). However, these trials have an inherent selection bias, and HRQOL in CHC patients may have been underestimated because of the exclusion of patients with comorbid illness. The aim of this study was to assess HRQOL in an unselected group of CHC patients and to identify factors associated with impairment in HRQOL. METHODS : A total of 220 consecutive eligible CHC patients were enrolled from a hepatology clinic. HRQOL was assessed by the short form 36 (SF-36) and comorbid illnesses were assessed by an interview. RESULTS : CHC patients had significantly lower SF-36 scores in all subscales and in the summary scales when compared to those of the healthy general population in the United States ( p < 0.001 ). Compared to CHC patients entering treatment trials, our patients had lower SF-36 scores on five subscales ( p < 0.001 ). The presence of comorbid illness was the most important predictor of HRQOL in CHC patients. However, CHC alone resulted in significantly lower SF-36 scores in all subscales and summary scales ( p ≤ 0.003 ) compared to those of the healthy U.S. population. There was no correlation between SF-36 scores and history of i.v. drug use or dependence, alcohol dependence, and serum aminotransferase levels. CONCLUSIONS : We conclude that unselected CHC patients presenting for medical evaluation have a reduced HRQOL, which is lower than that reported for CHC patients entering treatment trials. CHC alone is associated with significant impairment in HRQOL, but the presence of comorbid illness leads to further diminution in HRQOL.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75569/1/j.1572-0241.2001.04133.x.pd

Low pH Activates the Vacuolating Toxin of Helicobacter pylori, Which Becomes Acid and Pepsin Resistant

The protein toxin VacA, produced by cytotoxic strains of Helicobacter pylori, causes a vacuolar degeneration of cells, which eventually die. VacA is strongly activated by a short exposure to acidic solutions in the pH 1.5-5.5 range, followed by neutralization. Activated VacA has different CD and fluorescence spectra and a limited proteolysis fragmentation pattern from VacA kept at neutral pH. Moreover, activated VacA is resistant to pH 1.5 and to pepsin. The relevance of these findings to pathogenesis of H. pylori-induced gastrointestinal ulcers is discussed

Timing of primary tooth emergence among U.S. racial and ethnic groups

ObjectivesTo compare timing of tooth emergence among groups of American Indian (AI), Black and White children in the United States at 12 months of age.MethodsData were from two sources – a longitudinal study of a Northern Plains tribal community and a study with sites in Indiana, Iowa and North Carolina. For the Northern Plains study, all children (n = 223) were American Indian, while for the multisite study, children (n = 320) were from diverse racial groups. Analyses were limited to data from examinations conducted within 30 days of the child’s first birthday.ResultsAI children had significantly more teeth present (Mean: 7.8, Median: 8.0) than did Whites (4.4, 4.0, P < 0.001) or Blacks (4.5, 4.0, P < 0.001). No significant differences were detected between Black and White children (P = 0.58). There was no significant sex difference overall or within any of the racial groups.ConclusionsTooth emergence occurs at a younger age for AI children than it does for contemporary White or Black children in the United States.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135387/1/jphd12154.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/135387/2/jphd12154_am.pd

Comparing thigh muscle cross-sectional area and squat strength among national class Olympic weightlifters, power lifters, and bodybuilders

Few studies have compared anthropometric characteristics among national class athletes from different resistance training disciplines, such as Olympic Weightlifting (OL), Power Lifting (PL), and Bodybuilding (BB). Objective: The purpose of the current study was to determine if significant differences exist in the relationship between thigh muscle cross-sectional area and back squat strength among national class athletes from the sports of OL, PL, and BB. Methods: Fifteen national class athletes were assessed for back squat strength, mid-thigh circumference, and mid-thigh skinfold from which total thigh cross-sectional was estimated. A series of One-Way ANOVAs and Pearson Product Moment Correlations were used to compare groups and assess the relationship between variables. Results: The OL (200.18 + 25.16kg) and PL (205.45 + 17.28kg) groups were significantly stronger than the BB (160 + 16.80 kg; p \u3c 0.05) group. However, mid-thigh skinfold thickness (p = 0.36), mid-thigh circumference (p = 0.87), and estimated thigh cross-sectional area (p = 0.34) were not significantly different between groups. Thigh muscle cross-sectional area was weakly correlated to back squat strength in the OL (r = .42) and PL (r = .12) groups, but moderately correlated in the BB (r = .70) group. Conclusion: Thigh cross-sectional area was of relatively minor importance in determining back squat strength for the OL and PL groups, despite these groups being significantly stronger than the BB group. Specific training protocols will elicit different outcomes with regard to muscular hypertrophy that may or may not contribute to a functional increase in back squat strength

Development of a Core Curriculum Framework in Cariology for U.S. Dental Schools

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/153683/1/jddj002203372016806tb06133x.pd

Prevalence of hepatic iron overload and association with hepatocellular cancer in end-stage liver disease: results from the National Hemochromatosis Transplant Registry

Background : It is unclear whether mild to moderate iron overload in liver diseases other than hereditary haemochromatosis (HH) contributes to hepatocellular carcinoma. This study examined the association between hepatic iron grade and hepatocellular carcinoma in patients with end-stage liver disease of diverse aetiologies. Methods : The prevalence of hepatic iron overload and hepatocellular carcinoma was examined in 5224 patients undergoing liver transplantation. Explant pathology reports were reviewed for the underlying pathological diagnosis, presence of hepatocellular carcinoma and degree of iron staining. The distribution of categorical variables was studied using Χ 2 tests. Results : Both iron overload and hepatocellular carcinoma were the least common with biliary cirrhosis (1.8 and 2.8% respectively). Hepatocellular carcinoma was the most common in patients with hepatitis B (16.7%), followed by those with hepatitis C (15.1%) and HH (14.9%). In the overall cohort, any iron overload was significantly associated with hepatocellular carcinoma ( P =0.001), even after adjustment for the underlying aetiology of liver disease. The association between hepatic iron content and hepatocellular carcinoma was the strongest in patients with biliary cirrhosis ( P <0.001) and hepatitis C ( P <0.001). Conclusions : Iron overload is associated with hepatocellular carcinoma in patients with end-stage liver disease, suggesting a possible carcinogenic or cocarcinogenic role for iron in chronic liver disease.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75573/1/j.1478-3231.2007.01596.x.pd

NAFLD may be a common underlying liver disease in patients with hepatocellular Carcinoma in the United States

The incidence of hepatocellular carcinoma (HCC) in the United States is increasing, but the clinical characteristics of American patients with HCC have not been well described. The aims of this study were to determine the etiology of liver disease and short-term outcome among HCC patients presenting to a single center in the United States. One hundred five consecutive patients with HCC were studied; mean age was 59 years, 67% were men, and 76% were non-Hispanic white. The most common etiology of liver disease was hepatitis C (51%) and cryptogenic cirrhosis (29%). Half of the patients with cryptogenic cirrhosis had histologic or clinical features associated with nonalcoholic fatty liver disease (NAFLD). Fifty-three (50%) patients had HCC detected during surveillance (group I), whereas the remaining patients had symptomatic tumors (group II). Group I patients had smaller tumors ( P = 0.01), were more likely to be eligible for surgical treatment ( P = 0.005), and had a better medican survival compared with patients in group II ( P = 0.001). Patients with cryptogenic cirrhosis were less likely to have undergone HCC surveillance and had larger tumors at diagnosis. In conclusion, hepatitis C and cryptogenic liver disease are the most common etiologies of diseases in our patients with HCC. NAFLD accounted for at least 13% of the cases. Patients who underwent surveillance had smaller tumors and were more likely to be candidates for surgical or local ablative therapies. Because of the increasing incidence of NAFLD, further studies are needed to determine the risk of HCC in patients with NAFLD. (H EPATOLOGY 2002;36:1349-1354).Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/38413/1/1840360609_ftp.pd