The role of antiphase boundaries during ion sputtering and solid phase epitaxy of Si(001)

The Si(001) surface morphology during ion sputtering at elevated temperatures and solid phase epitaxy following ion sputtering at room temperature has been investigated using scanning tunneling microscopy. Two types of antiphase boundaries form on Si(001) surfaces during ion sputtering and solid phase epitaxy. One type of antiphase boundary, the AP2 antiphase boundary, contributes to the surface roughening. AP2 antiphase boundaries are stable up to 973K, and ion sputtering and solid phase epitaxy performed at 973K result in atomically flat Si(001) surfaces.Comment: 16 pages, 4 figures, to be published in Surface Scienc

Temporal variation in abundance and diversity of butterflies in Bornean rain forests: opposite impacts of logging recorded in different seasons

We used traps baited with fruit to examine how the temporal variation of butterflies within primary forest in Sabah, Borneo differed between species. In addition, we compared patterns of temporal variation in primary and selectively logged forest, and we tested the hypothesis that selective logging has different recorded impacts on species diversity of adults during the wet monsoon period and the drier remaining half of the year. Species of Satyrinae and Morphinae had significantly less-restricted flight periods than did species of Nymphalinae and Charaxinae, which were sampled mainly during the drier season. especially in primary forest. Species diversity of adults was significantly higher during the drier season in primary forest, but did not differ between seasons in logged forest. As a consequence, logging had opposite recorded impacts on diversity during wetter and drier seasons: primary forest had significantly higher diversity than logged forest during the drier season but significantly lower diversity than logged forest during the wetter monsoon season. The results of this study have important implications for the assessment of biodiversity in tropical rain forests, particularly in relation to habitat disturbance: short-term assessments that do not take account of seasonal variation in abundance are likely to produce misleading results, even in regions where the seasonal variation in rainfall is not that great

Prolonged Effect of Omeprazole on the 14 C-Urea Breath Test

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73649/1/j.1572-0241.1996.tb08294.x.pd

Effects of baseline abdominal pain and bloating on response to lubiprostone in patients with irritable bowel syndrome with constipation

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134450/1/apt13807.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134450/2/apt13807_am.pd

Preparation of atomically clean and flat Si(100) surfaces by low-energy ion sputtering and low-temperature annealing

Si(100) surfaces were prepared by wet-chemical etching followed by 0.3-1.5keV Ar ion sputtering, either at elevated or room temperature. After a brief anneal under ultrahigh vacuum conditions, the resulting surfaces were examined by scanning tunneling microscopy. We find that wet-chemical etching alone cannot produce a clean and flat Si(100) surface. However, subsequent 300eV Ar ion sputtering at room temperature followed by a 973K anneal yields atomically clean and flat Si(100) surfaces suitable for nanoscale device fabrication.Comment: 13 pages, 3 figures, to be published in Applied Surface Scienc

A randomized, controlled trial to assess a novel colorectal cancer screening strategy: the conversion strategy

Our study was a randomized, controlled trial to assess a novel strategy that provides comprehensive colorectal cancer screening in a single visit versus traditional sigmoidoscopy and, where appropriate, colonoscopy on a subsequent day. METHODS : Consecutive patients referred for screening were randomized to control or so-called “conversion” groups. Patients in the control group were prepared for sigmoidoscopy with oral phospho-soda. Those with an abnormal sigmoidoscopy were scheduled for colonoscopy on a future day after oral polyethylene glycol preparation. In the conversion group, patients were prepared with oral phospho-soda. Patients with a polyp >5 mm or multiple diminutive polyps were converted from sigmoidoscopy to colonoscopy, allowing comprehensive screening in a single visit. Clinical outcomes were assessed by postprocedure physician and patient questionnaires. RESULTS : Two hundred thirty-five patients were randomized (control = 121, conversion = 114). In the control group, 28% had an indication for colonoscopy. Three of 33 (9%) with an abnormal sigmoidoscopy did not return for colonoscopy. At colonoscopy, 27% had a proximal adenoma. In the conversion group, 28% had an abnormal sigmoidoscopy and underwent conversion to colonoscopy. Forty-one percent undergoing colonoscopy in the conversion group had a proximal adenoma. Physicians reported no differences in preparation or procedure difficulty, whereas patients reported no differences in the level of comfort or overall satisfaction between groups. When queried regarding preferences for future screening, 96% chose the conversion strategy. CONCLUSIONS : The conversion strategy led to similar outcomes compared to traditional screening while improving compliance with colonoscopy in patients with an abnormal sigmoidoscopy.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73097/1/j.1572-0241.2000.02231.x.pd

Active for a Day: Predictors of Relapse Among Previously Active Mass Event Participants

Background: To promote maintenance of sufficient physical activity (PA), better understanding of factors associated with behavioral relapse is needed. Purpose: To identify PA relapsers and predictors of this state in a large community sample of women who participated in 2 mass 10-km events in Ireland. Methods: Relapsers to ‘low active’ were identified at 3-month follow-up, and factors associated with relapse investigated. Results: 11% of the sample decreased their participation by at least 60 minutes of moderate-intensity PA per week and regressed to ‘insufficiently active.’ Adjusted analysis indicated relapse was associated with walking the event (OR = 1.40; 95% CI = 1.05–1.85) and not achieving tertiary education (OR = 1.49; 95% CI = 1.18–1.88). Normal-range BMI, training continuously, urban residence, and increases in self efficacy and positive perceptions of the physical environment were related to lower incidence of relapse. Conclusion: Education, living in an urban area, BMI, walking the event, training, and self efficacy are all associated with relapse and while mass events are a useful motivator for PA, strategies are required following events to maintain participation levels and generate a lasting public health impact

Soup to tree: the phylogeny of beetles inferred by mitochondrial metagenomics of a Bornean rainforest sample

In spite of the growth of molecular ecology, systematics and next-generation sequencing, the discovery and analysis of diversity is not currently integrated with building the tree-of-life. Tropical arthropod ecologists are well placed to accelerate this process if all specimens obtained via masstrapping, many of which will be new species, could be incorporated routinely in phylogeny reconstruction. Here we test a shotgun sequencing approach, whereby mitochondrial genomes are assembled from complex ecological mixtures via mitochondrial metagenomics, and demonstrate how the approach overcomes many of the taxonomic impediments to the study of biodiversity. DNA from ~500 beetle specimens, originating from a single rainforest canopy fogging sample from Borneo, was pooled and shotgun sequenced, followed by de novo assembly of complete and partial mitogenomes for 175 species. The phylogenetic tree obtained from this local sample was highly similar to that from existing mitogenomes selected for global coverage of major lineages of Coleoptera. When all sequences were combined, only minor topological changes are induced against this reference set, indicating an increasingly stable estimate of coleopteran phylogeny, whilst the ecological sample expands the tip-level representation of several lineages. Robust trees generated from ecological samples now enable an evolutionary framework for ecology. Meanwhile, the inclusion of uncharacterized samples in the tree-of-life rapidly expands taxon and biogeographic representation of lineages without morphological identification. Mitogenomes from shotgun sequencing of unsorted environmental samples and their associated metadata, placed robustly into the phylogenetic tree, constitute novel DNA ‘superbarcodes’ for testing hypotheses regarding global patterns of diversity

Can endoscopic ultrasound or magnetic resonance cholangiopancreatography replace ERCP in patients with suspected biliary disease? A prospective trial and cost analysis

ERCP is the gold standard for pancreaticobiliary evaluation but is associated with complications. Less invasive diagnostic alternatives with similar capabilities may be cost-effective, particularly in situations involving low prevalence of disease. The aim of this study was to compare the performance of endoscopic ultrasound (EUS) with magnetic resonance cholangiopancreatography (MRCP) and ERCP in the same patients with suspected extrahepatic biliary disease. The economic outcomes of EUS-, MRCP-, and ERCP-based diagnostic strategies were evaluated. METHODS : Prospective cohort study of patients referred for ERCP with suspected biliary disease. MRCP and EUS were performed within 24 h before ERCP. The investigators were blinded to the results of the alternative imaging studies. A cost-utility analysis was performed for initial ERCP, MRCP, and EUS strategies for these patients. RESULTS : A total of 30 patients were studied. ERCP cholangiogram failed in one patient, and another patient did not complete MRCP because of claustrophobia. The final diagnoses ( n = 28 ) were CBD stone (mean = 4 mm; range = 3–6 mm) in five patients; biliary stricture in three patients, and normal biliary tree in 20. Two patients had pancreatitis after therapeutic ERCP, one after precut sphincterotomy followed by a normal cholangiogram. EUS was more sensitive than MRCP in the detection of choledocolithiasis (80% vs 40%), with similar specificity. MRCP had a poor specificity and positive predictive value for the diagnosis of biliary stricture (76%/25%) compared to EUS (100%/100%), with similar sensitivity. The overall accuracy of MRCP for any abnormality was 61% (95% CI = 0.41–0.78) compared to 89% (CI = 0.72–0.98) for EUS. Among those patients with a normal biliary tree, the proportion correctly identified with each test was 95% for EUS and 65% for MRCP ( p < 0.02 ). The cost for each strategy per patient evaluated was $1346 for ERCP,$1111 for EUS, and $1145 for MRCP. CONCLUSIONS : In this patient population with a low disease prevalence, EUS was superior to MRCP for choledocholithiasis. EUS was most useful for confirming a normal biliary tree and should be considered a low-risk alternative to ERCP. Although MRCP had the lowest procedural reimbursement, the initial EUS strategy had the greatest cost-utility by avoiding unnecessary ERCP examinations.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73885/1/j.1572-0241.2001.04245.x.pd