S-adenosyl-L-methionine: (S)-scoulerine 9-O-methyltransferase, a highly stereo- and regio-specific enzyme in tetrahydroprotoberberine biosynthesis

Suspension cultures of Berberis species are useful sources for the detection and isolation of a new enzyme which transfers the methyl group from S-adenosyl-L-methionine specifically to the 9-position of the (S)-enantiomer of scoulerine, producing (S)-tetrahydrocolumbamine. The enzyme was enriched 27-fold; it is not particle bound, has a pH optimum of 8.9, a molecular weight of 63 000 and shows a high degree of substrate specificity

Dual position locking joint design for a medical walker

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2010.Cataloged from PDF version of thesis.Includes bibliographical references (p. 19).In this thesis we analyzed a joint created for a medical walker currently in the prototyping stage of development. The walker is designed to help a user stand up from a seated position. The joint holds two legs of the walker together in an 'x' shape. It must be able to lock in two positions and support the full weight of the user while he or she is getting up. We looked at four different locking mechanisms including a spring loaded pull pin, a friction bearing, a clutch, and an electronic solenoid. After weighing the pros and cons of each mechanism we recommend and present a design using the pull pin. In order to determine the strength and deflection of the loaded pin we modeled it both as a cantilevered beam, and a simply supported beam with three points of contact. We compared the hand calculations to FEA of solid models and found that modeling the pin as a simply supported beam is more accurate than the cantilever representation.by Eric M. Beecher.S.B

Biosynthesis of the protoberberine alkaloid jatrorrhizine

Feeding experiments with distant single or doubly labelled precursors show that the methylene dioxy group of berberine is opened in the formation of jatrorrhizine

The variation in morphology of perennial ryegrass cultivars throughout the grazing season and effects on organic matter digestibility

peer-reviewedThe grass plant comprises leaf, pseudostem, true stem (including inflorescence) and dead material. These components differ in digestibility, and variations in their relative proportions can affect sward quality. The objective of this study was to determine the change in the proportion and organic matter digestibility (OMD) of leaf, pseudostem, true stem and dead components of four perennial ryegrass cultivars (two tetraploids: Astonenergy and Bealey and two diploids: Abermagic and Spelga) throughout a grazing season. The DM proportions and in vitro OMD of leaf, pseudostem, true stem and dead in all cultivars were determined during ten grazing rotations between May 2011 and March 2012. There was an interaction between rotation and cultivar for leaf, pseudostem, true stem and dead proportions. In May and June, Astonenergy had the highest leaf and lowest true stem proportion (P pseudostem > true stem > dead. Bealey had the highest combined leaf and pseudostem proportion 0·92, which explains why it had the highest OMD. In this study, the tetraploid cultivars had the highest leaf and pseudostem proportion and OMD. For accurate descriptions of a sward in grazing studies and to accurately determine sward morphological composition, pseudostem should be separated from true stem, particularly during the reproductive stage when true stem is present

Scherzando

https://digitalcommons.library.umaine.edu/mmb-ps/2262/thumbnail.jp

Gastrointestinal tract size, total-tract digestibility, and rumen microflora in different dairy cow genotypes

peer-reviewedThe superior milk production efficiency of Jersey (JE) and Jersey × Holstein-Friesian (JE × HF) cows compared with Holstein-Friesian (HF) has been widely published. The biological differences among dairy cow genotypes, which could contribute to the milk production efficiency differences, have not been as widely studied however. A series of component studies were conducted using cows sourced from a longer-term genotype comparison study (JE, JE × HF, and HF). The objectives were to (1) determine if differences exist among genotypes regarding gastrointestinal tract (GIT) weight, (2) assess and quantify whether the genotypes tested differ in their ability to digest perennial ryegrass, and (3) examine the relative abundance of specific rumen microbial populations potentially relating to feed digestibility. Over 3 yr, the GIT weight was obtained from 33 HF, 35 JE, and 27 JE × HF nonlactating cows postslaughter. During the dry period the cows were offered a perennial ryegrass silage diet at maintenance level. The unadjusted GIT weight was heavier for the HF than for JE and JE × HF. When expressed as a proportion of body weight (BW), JE and JE × HF had a heavier GIT weight than HF. In vivo digestibility was evaluated on 16 each of JE, JE × HF, and HF lactating dairy cows. Cows were individually stalled, allowing for the total collection of feces and were offered freshly cut grass twice daily. During this time, daily milk yield, BW, and dry matter intake (DMI) were greater for HF and JE × HF than for JE; milk fat and protein concentration ranked oppositely. Daily milk solids yield did not differ among the 3 genotypes. Intake capacity, expressed as DMI per BW, tended to be different among treatments, with JE having the greatest DMI per BW, HF the lowest, and JE × HF being intermediate. Production efficiency, expressed as milk solids per DMI, was higher for JE than HF and JE × HF. Digestive efficiency, expressed as digestibility of dry matter, organic matter, N, neutral detergent fiber, and acid detergent fiber, was higher for JE than HF. In grazing cows (n = 15 per genotype) samples of rumen fluid, collected using a transesophageal sampling device, were analyzed to determine the relative abundance of rumen microbial populations of cellulolytic bacteria, protozoa, and fungi. These are critically important for fermentation of feed into short-chain fatty acids. A decrease was observed in the relative abundance of Ruminococcus flavefaciens in the JE rumen compared with HF and JE × HF. We can deduce from this study that the JE genotype has greater digestibility and a different rumen microbial population than HF. Jersey and JE × HF cows had a proportionally greater GIT weight than HF. These differences are likely to contribute to the production efficiency differences among genotypes previously reported

Direct Observation of Dynamic Symmetry Breaking above Room Temperature in Methylammonium Lead Iodide Perovskite

Lead halide perovskites such as methylammonium lead triiodide (MAPI) have outstanding optical and electronic properties for photovoltaic applications, yet a full understanding of how this solution processable material works so well is currently missing. Previous research has revealed that MAPI possesses multiple forms of static disorder regardless of preparation method, which is surprising in light of its excellent performance. Using high energy resolution inelastic X-ray (HERIX) scattering, we measure phonon dispersions in MAPI and find direct evidence for another form of disorder in single crystals: large amplitude anharmonic zone-edge rotational instabilities of the PbI_6 octahedra that persist to room temperature and above, left over from structural phase transitions that take place tens to hundreds of degrees below. Phonon calculations show that the orientations of the methylammonium couple strongly and cooperatively to these modes. The result is a non-centrosymmetric, instantaneous local structure, which we observe in atomic pair distribution function (PDF) measurements. This local symmetry breaking is unobservable by Bragg diffraction, but can explain key material properties such as the structural phase sequence, ultra low thermal transport, and large minority charge carrier lifetimes despite moderate carrier mobility.Comment: 30 pages, 11 figure

Elementary Music Supervision in the Logan City Schools: Its Relationship to the General Music Program in its Historical Setting

This study has been made in response to some of the problems observed in the general music program of the Logan City School District during the five-year period 1960-1965. As the number of classroom units increased during these years, the function of the elementary music supervisor was modified. Supervision as a visiting music teacher on a bi-monthly schedule gradually changed to supervision as a teacher consultant whose scheduled classroom visits were once a month or less. During these scheduled visits, the classroom teacher planned and presented two or more music lessons for observation. Other scheduled contacts were either teacher-supervisor consultations, or were supervisor demonstrations int he classrooms, prepared in response to the teacher\u27s requests and needs. More and more supervision time was spent in an effort to help the teacher to teach music, rather than in helping the pupils to sing. This shift of responsibility for teaching the general music program, from the supervisor to the classroom teacher, fostered many problems. Most of these problems were consequence are commented upon in this study. The problem of the low-singer crossed classroom and school boundaries and seemed to reflect the values of the whole social climate rather than poor teaching in any one area. Pressures which placed value on little boys as prospective athletes also seemed to push them into shamed avoidance of their soprano child\u27s voice. Boys reached for deep, adult bass tones with avid dedication and ignored the demands of the melody and whatever harm they were doing to their ability to hear and to sing accurately. Some school-room factors seemed to aggravate this problem; teachers and administrators observed accurate singers become progressively more offended by the quality of music made by groups which included out-of-tune singers. When musically oriented pupils began to take private piano lessons, they seemed to realize that they would learn all about music through regular practice on their instrument, and soon abandoned all but token participation in the classroom music period. They pretended to be bass singers, joined the out-of-tuners, and encouraged other boys to do the same. This process accelerated under an idealized man teacher, who was able to sing in a comfortable low voice, or under musically permissive teachers who did not know what musical standards to expect or how to achieve them