Quantifying phosphoric acid in high-temperature polymer electrolyte fuel cell components by X-ray tomographic microscopy.

Synchrotron-based X-ray tomographic microscopy is investigated for imaging the local distribution and concentration of phosphoric acid in high-temperature polymer electrolyte fuel cells. Phosphoric acid fills the pores of the macro- and microporous fuel cell components. Its concentration in the fuel cell varies over a wide range (40-100 wt% H3PO4). This renders the quantification and concentration determination challenging. The problem is solved by using propagation-based phase contrast imaging and a referencing method. Fuel cell components with known acid concentrations were used to correlate greyscale values and acid concentrations. Thus calibration curves were established for the gas diffusion layer, catalyst layer and membrane in a non-operating fuel cell. The non-destructive imaging methodology was verified by comparing image-based values for acid content and concentration in the gas diffusion layer with those from chemical analysis.

Phase II study of bevacizumab with liposomal doxorubicin for patients with platinum- and taxane-resistant ovarian cancer.

BACKGROUND: Suppression of neoangiogenesis and pegylated liposomal doxorubicin (PLD) each contribute to the management of platinum-resistant/refractory ovarian cancer. The aim of this study is to test the combination of bevacizumab and PLD in women with resistant or refractory ovarian cancer. METHODS: Eligibility criteria were no more than two prior treatments with platinum-containing regimens and one additional regimen, without anthracyclines. Treatment was administered every 3 weeks (bevacizumab 15 mg/kg beginning on cycle 2 and PLD 30 mg/m(2)). The primary end point was progression-free survival (PFS) at 6 months; the secondary end points included side-effects, overall response rates (ORR) and survival (OS). RESULTS: Forty-six patients were enrolled. The average number of courses administered was 7. The median PFS was 6.6 months (range 1-24.6 months) according to Gynecologic Cancer Intergroup Committee (GCIC) criteria and 7.8 months (range 2-13.3 months) according to Response Evaluation Criteria in Solid Tumors (RECIST). The median OS was 33.2 months (range 3-37.5+ months). The ORR was 30.2% [95% confidence interval (CI) 17.2-46.1] and the clinical benefit rate (CBR) was 86.1% (95% CI 72.1-94.7). Adverse events included mucosal and dermal erosions (30% grade 3) and asymptomatic cardiac dysfunction. Additional toxic effects included hypertension, headache, renal dysfunction and proteinuria, wound healing delay, and one episode each of central nervous system (CNS) ischemia and hemolytic uremic syndrome. CONCLUSION: PLD with bevacizumab has improved activity in recurrent ovarian cancer with increased toxicity.

Phase IB study of the combination of docetaxel, gemcitabine, and bevacizumab in patients with advanced or recurrent soft tissue sarcoma: the Axtell regimen.

BACKGROUND: To assess the response of patients with soft tissue sarcoma (STS) to the combination of docetaxel, bevacizumab, and gemcitabine. Vascular endothelial growth factor (VEGF)-A levels and expression of VEGF-A and VEGF receptors 1 and 2 were evaluated. PATIENTS AND METHODS: Thirty-eight chemotherapy-naive patients with STS were enrolled. A dose-finding study for gemcitabine from 1000, 1250, then 1500 mg/m(2) was done in nine patients (three cohorts), followed by an expansion cohort of 27 patients. Dose of docetaxel was 50 mg/m(2), bevacizumab was 5 mg/kg, and gemcitabine was 1500 mg/m(2), every 2 weeks. Serum VEGF-A was measured by enzyme-linked immunosorbent assay and tissue VEGF-A and its receptors by immunohistochemistry. RESULTS: The median follow-up was 36 months. The overall response rate observed was 31.4%, with 5 complete and 6 partial responses, and 18 stable diseases lasting for a median of 6 months. There was no significant hematologic toxicity. The adverse events with the highest grade were attributed to bevacizumab. There was no correlation of VEGF pathway biomarkers with outcome. CONCLUSIONS: The combination of gemcitabine, docetaxel, and bevacizumab is safe and effective in patients with STS. The most concerning adverse events were consequences of bevacizumab administration. The benefit of bevacizumab in this patient population remains unclear.

Influenza A(H1N1)pdm09 antibodies after pandemic and trivalent seasonal influenza vaccination as well as natural infection in November 2010 in Hamburg, Germany.

The 2009 influenza pandemic has introduced the new re-assorted influenza A(H1N1)pdm09 virus which recirculated during the 2010/11 influenza season. Before that season, it was possible to acquire protective immunity either by pandemic or seasonal influenza vaccination against influenza A(H1N1)pdm09 or by natural infection. To obtain data on vaccination coverage and antibody levels in a reference population and to calculate whether or not the herd immunity threshold (HIT, calculated as 33% given an R0 of 1.5) was reached at the beginning of the 2010/11 season we performed a seroprevalence study in November 2010 in Hamburg, Germany. Antibody titres were assessed applying a haemagglutination inhibition test. Vaccination coverage was very low: 14% for pandemic and 11% for seasonal 2010/11 vaccinations. Even in those with underlying risk factors, vaccination coverage was not much higher: 17% for both vaccines. Serological analysis revealed antibody titres of ≥1:10 in 135 of 352 (38%) and of ≥1:40 in 61 of 352 study participants (17%). Specific antibodies were measurable in 26% of those without history of vaccination or natural infection, indicating a high proportion of subclinical and mild influenza disease. Nevertheless, the HIT was not reached, leaving the majority of the population susceptible to influenza A(H1N1)pdm09 and its potential complications.

Phase I study of capecitabine in combination with cisplatin and irinotecan in patients with advanced solid malignancies.

PURPOSE: This phase I trial assessed the safety and the maximum tolerated dose of capecitabine given for 10 days prior to a combination of cisplatin and irinotecan in patients with advanced solid malignancies. It also evaluated the changes in cisplatin DNA adducts induced by capecitabine. PATIENTS AND METHODS: Patients with refractory solid tumors who had not failed 5-fluorouracil (5-FU) analogs or topoisomerase I inhibitors were eligible. All cohorts of patients first received a 28-day cycle of cisplatin and irinotecan. Both drugs were given at a dose of 50 mg/m(2) intravenously on day 1, followed by irinotecan on days 8 and 15 at the same dose. The first cycle served as an internal control. Starting from the second cycle, patients received increasing doses per cohort of capecitabine from day 1 to 10 of each cycle, followed by cisplatin on day 11 and irinotecan on days 11, 18 and 25, both at same doses as the first cycle. Cycles were repeated every 38 days. The starting dose of capecitabine was 500 mg/m(2)/day which was escalated by 250 mg/m(2)/day in the subsequent cohort of patients to reach the maximum tolerated dose (MTD). Later, additional patients were treated at the MTD of capecitabine to further evaluate the safety, pharmacodynamics, and tumor response. Patients blood was tested for cisplatin-DNA adducts to determine the impact of capecitabine on cisplatin-based therapy. RESULTS: Fifteen patients received at least 2 cycles of treatment. At 1,250 mg/m(2), two DLT of prolonged neutropenia of grade > or =3 were observed. The MTD for capecitabine was thus determined to be 1000 mg/m(2)/day. Fatigue and diarrhea of grade 1 or 2 were the most frequent toxicities at this dose level. No significant hematologic toxicity was observed at the MTD. Two complete and three partial remissions were observed. Four of the responders had received a platinum agent and/or 5-FU in the past. CONCLUSIONS: A sequential treatment with capecitabine followed by cisplatin and irinotecan is well tolerated and demonstrates clinical activity in patients with advanced solid malignancies. The influence of capecitabine, if any, on the efficacy of the cisplatin-irinotecan combination is not related to a variation in cisplatin-DNA adducts.

Radiology of epiploic appendages: acute appendagitis, post-infarcted appendages, and imaging natural history.

Our aim was to demonstrate the imaging characteristics of epiploic appendages in native, acute inflamed/ischemic and post-infarcted states through retrospective imaging analysis, with clinical and pathologic correlation, and to discuss clinical implications. Cases were gathered mostly retrospectively and reviewed for inclusion based on established diagnostic criteria. Radiology report text search was used to find cases, using terms "epiploic," "appendage," "appendagitis," and "peritoneal body." Data records included patient demographics, relevant clinical data, lesion size, location and apparent imaging composition, and the presence of change or stability in features over multiple studies. Pathologic and clinical data were sought and assessed for correlation. Imaging studies of 198 individuals were included (mean age 50, range 9-95), with a total of 228 lesions: 63 acute and 165 non-acute presentations. All included subjects had CT imaging and some had lesions visible on radiographs, MRI, PET/CT, and sonography. 23 subjects had more than one studied lesion. In addition to classic acute appendagitis, more frequently encountered are post-infarcted appendages either in situ along the colon, adhered to peritoneal or serosal surfaces, or freely mobile in the peritoneum as loose bodies. The majority of the non-acute varieties are recognizable due to peripheral calcification that develops over time following ischemic insult. Multiple cases demonstrated the imaging natural history and confirmed pathologic basis for imaging findings. In summary, acute and post-infarcted epiploic appendages have characteristic imaging appearances and natural history which should provide correct diagnosis in most cases. Incidental post-infarcted epiploica are more commonly encountered than acute presentations.

The solution structure of the N-terminal domain of riboflavin synthase.

The structure of the amino-terminal domain of Escherichia coli riboflavin synthase (RiSy) has been determined by NMR spectroscopy with riboflavin as a bound ligand. RiSy is functional as a 75 kDa homotrimer, each subunit of which consists of two domains which share very similar sequences and structures. The N-terminal domain (RiSy-N; 97 residues) forms a 20 kDa homodimer in solution which binds riboflavin with high affinity. The structure features a six-stranded antiparallel beta-barrel with a Greek-key fold, both ends of which are closed by an alpha-helix. One riboflavin molecule is bound per monomer in a site at one end of the barrel which is comprised of elements of both monomers. The structure and ligand binding are similar to that of the FAD binding domains of ferrodoxin reductase family proteins. The structure provides insights into the structure of the whole enzyme, the organisation of the functional trimer and the mechanism of riboflavin synthesis. C48 from the N-terminal domain is identified as the free cysteine implicated in a nucleophilic role in the synthesis mechanism, while H102 from the C-terminal domains is also likely to play a key role. Both are invariant in all known riboflavin synthase sequences.

Biosynthesis of riboflavin in plants. The ribA gene of Arabidopsis thaliana specifies a bifunctional GTP cyclohydrolase II/3,4-dihydroxy-2-butanone 4-phosphate synthase.

A cDNA segment from Arabidopsis thaliana with similarity to the ribA gene of Bacillus subtilis was sequenced. A similar gene was cloned from tomato. The open reading frame of A. thaliana was fused to the malE gene of Escherichia coli and was expressed in a recombinant E. coli strain. The recombinant fusion protein was purified and shown to have GTP cyclohydrolase II activity as well as 3,4-dihydroxy-2-butanone 4-phosphate synthase activity. The cognate gene was amplified by polymerase chain reaction from chromosomal Arabidopsis DNA and was shown to contain six introns. Intron 4 is located in the region connecting the GTP cyclohydrolase II and 3,4-dihydroxy-2-butanone 4-phosphate synthase domain of the putative domains catalyzing the two reaction steps. By comparison with the bacterial ribA gene, the Arabidopsis gene contains an additional 5' element specifying about 120 amino acid residues. This segment contains numerous serine and threonine residues and does not show similarity with other known sequences. The N-terminal segment is not required for catalytic activity and is likely to serve as signal sequence for import into chloroplasts.

Transcriptional profiling of human mammary carcinoma cell lines reveals PKW, a new tumor-specific gene.

In order to identify genes associated with distinct stages of mammary carcinoma we have investigated the transcriptional profile of normal mammary gland epithelial cells, cell lines derived from primary tumors, from bone marrow micrometastases and from ascites fluid. mRNA's for ribosomal protein L41 and URIM (Up-Regulated In Metastasis) were consistently increased in all cells derived from metastatic lesions. mRNA for human secreted frizzled-related protein (hsFRP) was found to be dramatically down-regulated in all mammary tumor cells compared to non-transformed mammary gland epithelial cells. mRNA for Human Hypoxia Related Factor--2 (HRF-2) and a transcript including the human mitochondrial control region were significantly overexpressed in the cell lines derived from primary tumors and ascites fluid. A new gene, referred to as PKW, was only expressed in one of the primary tumor cell lines, the one derived from a medullary carcinoma. The small and the large transcript which are derived by differential splicing encode potential proteins comprising 95 aa and 130 aa, sharing 88 aa at the N-terminus. The IEP's suggest a nuclear localization of the proteins. Surprisingly mRNA for the new gene was detected only in the salivary gland, but not in other adult human tissues and a restricted panel of embryonic tissues. The same holds true for a panel of human tumor cell lines and cell lines derived from ductal mammary carcinoma. RT-PCR revealed expression of PKW in 4 out of 11 breast carcinomas.

Stabling is associated with airway inflammation in young Arabian horses.

We examined the effect of stabling on upper and lower airway inflammation in 14 yearling Arabian horses that had been at pasture since birth. Horses were divided into 2 groups of 7. One group was stabled for 3 months and the other remained at pasture. The groups were then switched over for another 3 months. The nasopharynx, guttural pouches and trachea were examined endoscopically and bronchoalveolar lavage performed every month. An upper airway inflammation score was devised based on the magnitude of pharyngeal lymphoid hyperplasia and guttural pouch inflammation. During stabling this score remained constant, whereas it decreased during the 3 months at pasture. Stabling was also associated with a higher number and percentage of neutrophils in bronchoalveolar lavage fluid and with a smaller percentage of lymphocytes. There was no correlation between upper airway inflammation score and bronchoalveolar lavage cytology. During a nasal occlusion test, dorsal displacement of the soft palate occurred more times in stabled than in pastured horses, but this was heavily biased by the results from one animal. We conclude that stabling is associated with inflammation of both the upper and lower airway of young horses.

Classroom evaluation of the Arlyn Arm robotic workstation.

High school and junior high school students with neuromuscular weakness and other disorders of the arms evaluated a recently commercialized robotic workstation, the Arlyn Arm, to carry out art projects and science experiments. These tasks were designed for independent execution with the workstation using standard or custom-designed tools. Each task was divided into subtasks, and the execution time of each subtask was determined as a measure of efficiency. Special attention was given to the causes of required experimenter intervention. While subjects easily accomplished some subtasks, others required considerable intervention. Most of these interventions could be avoided by further customizing accessories. It is concluded that the Arlyn Arm workstation could be of considerable benefit in a classroom setting to persons with severe neuromuscular disorders.

Life expectancy in four U.S. racial/ethnic populations: 1990.

Previous estimates of life expectancy in the United States have not corrected for biases in population and mortality data, and no study has examined life expectancy in U.S. Asian/Pacific Islander and American Indian populations. We used information on population undercounts by race/ethnicity in the census and on misclassification of race/ethnicity on death certificates to calculate life expectancy for black, white, American Indian, and Asian men and women in the United States in 1990. Correction for undercount and misclassification had little effect on life expectancy estimates for whites, but it substantially decreased estimates for American Indians and Asians. Asian men had life expectancies of 82.0 years and Asian women 85.8 years--the highest life expectancies reported for any population in the world and beyond the limit predicted by some current theories.

Single-channel vibrotactile supplements to visual perception of intonation and stress.

Two experiments were conducted to explore the effectiveness of a single vibrotactile stimulator to convey intonation (question versus statement) and contrastive stress (on one of the first three words of four 4- or 5-word sentences). In experiment I, artificially deafened normal-hearing subjects judged stress and intonation in counterbalanced visual-alone and visual-tactile conditions. Six voice fundamental frequency-to-tactile transformations were tested. Two sentence types were voiced throughout, and two contained unvoiced consonants. Benefits to speechreading were significant, but small. No differences among transformations were observed. In experiment II, only the tactile stimuli were presented. Significant differences emerged among the transformations, with larger differences for intonation than for stress judgments. Surprisingly, tactile-alone intonation identification was more accurate than visual-tactile for several transformations.

Biosynthesis of riboflavin: an unusual riboflavin synthase of Methanobacterium thermoautotrophicum.

Riboflavin synthase was purified by a factor of about 1,500 from cell extract of Methanobacterium thermoautotrophicum. The enzyme had a specific activity of about 2,700 nmol mg(-1) h(-1) at 65 degrees C, which is relatively low compared to those of riboflavin synthases of eubacteria and yeast. Amino acid sequences obtained after proteolytic cleavage had no similarity with known riboflavin synthases. The gene coding for riboflavin synthase (designated ribC) was subsequently cloned by marker rescue with a ribC mutant of Escherichia coli. The ribC gene of M. thermoautotrophicum specifies a protein of 153 amino acid residues. The predicted amino acid sequence agrees with the information gleaned from Edman degradation of the isolated protein and shows 67% identity with the sequence predicted for the unannotated reading frame MJ1184 of Methanococcus jannaschii. The ribC gene is adjacent to a cluster of four genes with similarity to the genes cbiMNQO of Salmonella typhimurium, which form part of the cob operon (this operon contains most of the genes involved in the biosynthesis of vitamin B12). The amino acid sequence predicted by the ribC gene of M. thermoautotrophicum shows no similarity whatsoever to the sequences of riboflavin synthases of eubacteria and yeast. Most notably, the M. thermoautotrophicum protein does not show the internal sequence homology characteristic of eubacterial and yeast riboflavin synthases. The protein of M. thermoautotrophicum can be expressed efficiently in a recombinant E. coli strain. The specific activity of the purified, recombinant protein is 1,900 nmol mg(-1) h(-1) at 65 degrees C. In contrast to riboflavin synthases from eubacteria and fungi, the methanobacterial enzyme has an absolute requirement for magnesium ions. The 5' phosphate of 6,7-dimethyl-8-ribityllumazine does not act as a substrate. The findings suggest that riboflavin synthase has evolved independently in eubacteria and methanobacteria.

A computational approach to analyzing sentential speech perception: phoneme-to-phoneme stimulus-response alignment.

A solution to the following problem is presented: Obtain a principled approach to studying error patterns in sentence-length responses obtained from subjects who were instructed to simply report what a talker had said. The solution is a sequence comparator that performs phoneme-to-phoneme alignment on transcribed stimulus and response sentences. Data for developing and testing the sequence comparator were obtained from 139 normal-hearing subjects who lipread (speechread) 100 sentences and from 15 different subjects who identified nonsense syllables by lipreading. Development of the sequence comparator involved testing two different costs metrics (visemes versus Euclidean distances) and two related comparison algorithms. After alignments with face validity were achieved, a validation experiment was conducted for which measures from random versus true stimulus-response sentence pairs were compared. Measures of phonemes correct and substitution uncertainty were found to be sensitive to the nature of the sentence pairs. In particular, correct phoneme matches were extremely rare in random pairings in comparison with true pairs. Also, an information-theoretic measure of uncertainty for substitutions in true versus random pairings showed that uncertainty was always higher for random than for true pairs.

Crystallization and preliminary crystallographic analysis of the recombinant N-terminal domain of riboflavin synthase.

Riboflavin synthase catalyzes the final step in the biosynthesis of riboflavin. Animals and humans lack this enzyme, whereas many bacteria and certain yeasts are absolutely dependent on endogenous riboflavin synthesis. Riboflavin synthase is therefore an attractive target for chemotherapy. The N-terminal domain of riboflavin synthase forms a dimer in solution and is capable of strongly binding riboflavin. It can serve as a model for the binding site of the native enzyme. Structural information obtained from this domain at high resolution will be helpful in the determination of the binding mode of riboflavin and thus for the development of antimicrobial drugs. Here, the crystallization and preliminary crystallographic analysis of the N-terminal domain of riboflavin synthase are reported. The crystals belong to the space group C222(1), with unit-cell parameters a = 50.3, b = 104.7, c = 85.3 A, alpha = beta = gamma = 90 degrees, and diffract to 2.6 A resolution.

Speechreading sentences with single-channel vibrotactile presentation of voice fundamental frequency.

The main goal of this study was to investigate the efficacy of four vibrotactile speechreading supplements. Three supplements provided single-channel encodings of fundamental frequency (F0). Two encodings involved scaling and shifting glottal pulses to pulse rate ranges suited to tactual sensing capabilities; the third transformed F0 to differential amplitude of two fixed-frequency sinewaves. The fourth supplement added to one of the F0 encodings a second vibrator indicating high-frequency speech energy. A second goal was to develop improved methods for experimental control. Therefore, a sentence corpus was recorded on videodisc using two talkers whose speech was captured by video, microphone, and electroglottograph. Other experimental control issues included use of visual-alone control subjects, a multiple-baseline, single-subject design replicated for each of 15 normal-hearing subjects, sentence and syllable pre- and post-tests balanced for difficulty, and a speechreading screening test for subject selection. Across 17 h of treatment and 5 h of visual-alone baseline testing, each subject performed open-set sentence identification. Covariance analyses showed that the single-channel supplements provided a small but significant benefit, whereas the two-channel supplement was not effective. All subjects improved in visual-alone speechreading and maintained individual differences across the experiment. Vibrotactile benefit did not depend on speechreading ability.