Proteolytic inactivation of human α1 antitrypsin by human stromelysin

Abstractα1Antitrypsin (α1AT) is the main physiological inhibitor of neutrophil elastase, a serine protease which has been implicated in tissue degradation at inflammatory sites. We report here that the connective tissue metalloproteinase, stromelysin, cleaved α1AT (54 kDa), producing fragments of approximately 50 kDa and 4 kDa, as shown by gel electrophoresis. The cleavage of α1AT was accompanied by inactivation of its elastase inhibitory capacity. Isolation of the 4 kDa fragment by reversed-phase HPLC, followed by N-terminal amino acid sequencing, demonstrated that the cleavage of α1AT occurred at the Pro357-Met358 (P2P1) peptide bond, one peptide bond to the N-terminal side of the inhibitory site. We suggest that stromelysin may potentiate the activity of neutrophil elastase by proteolytically inactivating α1AT

SNAP I POWER CONVERSION SYSTEM DEVELOPMENT. Period covered: February 1, 1957 to June 30, 1959

Development of the SNAP I power conversion system is described. The system is designed to convert the thermal energy produced by the decay of radioisotopes into 500 watts of electrical energy by means of a mercury Funkine cycle. A list of specific accomplishments of the program is included. (J.R.D.

GALEX J201337.6+092801: The lowest gravity subdwarf B pulsator

We present the recent discovery of a new subdwarf B variable (sdBV), with an exceptionally low surface gravity. Our spectroscopy of J20136+0928 places it at Teff = 32100 +/- 500, log(g) = 5.15 +/- 0.10, and log(He/H) = -2.8 +/- 0.1. With a magnitude of B = 12.0, it is the second brightest V361 Hya star ever found. Photometry from three different observatories reveals a temporal spectrum with eleven clearly detected periods in the range 376 to 566 s, and at least five more close to our detection limit. These periods are unusually long for the V361 Hya class of short-period sdBV pulsators, but not unreasonable for p- and g-modes close to the radial fundamental, given its low surface gravity. Of the ~50 short period sdB pulsators known to date, only a single one has been found to have comparable spectroscopic parameters to J20136+0928. This is the enigmatic high-amplitude pulsator V338 Ser, and we conclude that J20136+0928 is the second example of this rare subclass of sdB pulsators located well above the canonical extreme horizontal branch in the HR diagram.Comment: 5 pages, accepted for publication in ApJ Letter

Is 8:30 a.m. Still Too Early to Start School? A 10:00 a.m. School Start Time Improves Health and Performance of Students Aged 13-16.

While many studies have shown the benefits of later school starts, including better student attendance, higher test scores, and improved sleep duration, few have used starting times later than 9:00 a.m. Here we report on the implementation and impact of a 10 a.m. school start time for 13 to 16-year-old students. A 4-year observational study using a before-after-before (A-B-A) design was carried out in an English state-funded high school. School start times were changed from 8:50 a.m. in study year 0, to 10 a.m. in years 1-2, and then back to 8:50 a.m. in year 3. Measures of student health (absence due to illness) and academic performance (national examination results) were used for all students. Implementing a 10 a.m. start saw a decrease in student illness after 2 years of over 50% (p < 0.0005 and effect size: Cohen's d = 1.07), and reverting to an 8:50 a.m. start reversed this improvement, leading to an increase of 30% in student illness (p < 0.0005 and Cohen's d = 0.47). The 10:00 a.m. start was associated with a 12% increase in the value-added number of students making good academic progress (in standard national examinations) that was significant (<0.0005) and equivalent to 20% of the national benchmark. These results show that changing to a 10:00 a.m. high school start time can greatly reduce illness and improve academic performance. Implementing school start times later than 8:30 a.m., which may address the circadian delay in adolescents' sleep rhythms more effectively for evening chronotypes, appears to have few costs and substantial benefits