A sermon, delivered at the meeting house of the second parish in Portland, August 20, 1812 : on the occasion of the national fast /

Published at the particular request of the congregation.

A sermon, preached in Hingham and Quincy, 20th August 1812, the day of the national fast, on account of the war with Great Britain /

Bibliogr.

Bis-and tris (amidine) fluoroboron cations and related systems studies by Multinuclear NMR and fast atom bombardment mass spectometry

The formation and the isolation of fluoroboron salts, (D2BF2+)(PF6-), (DD'BF2+)(PF6-) and (D3BF2+)(PF6-)2, have been carried out. 1,8-Diazabicyclo [5,4.0]undec-7-ene (DBU) and 1,5-diazabicyclo[4,3,O]non-5-ene (DBN), extremely strong organic bases, were introduced into the fluoroboron cation systems and induced a complicated redistribution reaction in the D/BF3/BC13 systems. The result was the formation of all BFnCI4-n-, D.BFnCI3-n and fluoroboron cation species which were detected by 19p and 11B NMR spectrometry. The displacement reaction of CI- from these D.BFnCI3-n (n = 1 and 2) species by the second entering ligand is much faster than in other nitrogen donor containing systems which have been previously studied. Tetramethylguanidine, oxazolines and thiazolines can also produce similar reactions in D/BF3/BCI3 systems, but no significant BFnC4-n- species were observed. As well as influences of their basicity and their steric hindrance, N=C-R(X) (X = N, 0 or S) and N=C( X)2 (X = N or S) structures of ligands have significant effects on the fonnationof fluoroboron cations and the related NMR parameters. D3BF2+ and some D2BF2+ show the expected inertness, but (DBU)2BF2+ shows an interestingly high reactivity. (D2BF2+)(X-) formed from weak organic bases such as pyridine can react with stronger organic bases and form DD'BF2+ and D'2BF2+ in acetone or nitromethane. Fast atom bombardment mass spectrometry is doubly meaningful to this work. Firstly, FABMS can be directly applied to the complicated fluoroboron cation containing solution systems as an excellent complementary technique to multinuclear NMR. Secondly, the gas-phase ion substitution reaction of (D2BF2+)(PF6-) with the strong organic bases is successfully observed in a FABMS ion source when the B-N bond is not too strong in these cations.

THE INFLUENCE OF LENGTH CHANGE SPEED AND DIRECTION ON DYNAMIC FUNCTION POTENTIATION IN FAST MOUSE MUSCLE

The purpose of this study was to test the hypothesis that the potentiation of dynamic function was dependent upon both length change speed and direction. Mouse EDL was cycled in vitro (25º C) about optimal length (Lo) with constant peak strain (± 2.5% Lo) at 1.5, 3.3 and 6.9 Hz before and after a conditioning stimulus. A single pulse was applied during shortening or lengthening and peak dynamic (concentric or eccentric) forces were assessed at Lo. Stimulation increased peak concentric force at all frequencies (range: 19 ± 1 to 30 ± 2%) but this increase was proportional to shortening speed, as were the related changes to concentric work/power (range: -15 ± 1 to 39 ± 1 %). In contrast, stimulation did not increase eccentric force, work or power at any frequency. Thus, results reveal a unique hysteresis like effect for the potentiation of dynamic output wherein concentric and eccentric forces increase and decrease, respectively, with work cycle frequency.

A sermon, delivered at the meeting house of the second parish in Portland, August 20, 1812 : on the occasion of the national fast

Published at the particular request of the congregation.

A sermon, preached in Boston, July 23, 1812, the day of the publick fast, appointed by the Executive of the Commonwealth of Massachusetts, in consequence of the declaration of war against Great Britain

Published at the request of the hearers Printed by Greenough and Stebbins

A sermon, preached in Hingham and Quincy, 20th August 1812, the day of the national fast, on account of the war with Great Britain

Printed by Joshua Belcher

THE INFLUENCE OF LENGTH CHANGE SPEED AND DIRECTION ON DYNAMIC FUNCTION POTENTIATION IN FAST MOUSE MUSCLE

The purpose of this study was to test the hypothesis that the potentiation of dynamic function was dependent upon both length change speed and direction. Mouse EDL was cycled in vitro (250 C) about optimal length (Lo) with constant peak strain (± 2.5% Lo) at 1.5,3.3 and 6.9 Hz before and after a conditioning stimulus. A single pulse was applied during shortening or lengthening and peak dynamic (concentric or eccentric) forces were assessed at Lo. Stimulation increased peak concentric force at all frequencies (range: 19±1 to 30 ± 2%) but this increase was proportional to shortening speed, as were the related changes to concentric work/power (range: -15 ± 1 to 39 ± 1 %). In contrast, stimulation did not increase eccentric force, work or power at any frequency. Thus, results reveal a unique hysteresis like effect for the potentiation of dynamic output wherein concentric and eccentric forces increase and decrease, respectively, with work cycle frequency.

The Fast Regulation of Photosynthesis in Diatoms: an inquiry into the physiological and physical origins of non-photochemical chlorophyll fluorescence quenching.

Diatoms are renowned for their robust ability to perform NPQ (Non-Photochemical Quenching of chlorophyll fluorescence) as a dissipative response to heightened light stress on photosystem II, plausibly explaining their dominance over other algal groups in turbulent light environs. Their NPQ mechanism has been principally attributed to a xanthophyll cycle involving the lumenal pH regulated reversible de-epoxidation of diadinoxanthin. The principal goal of this dissertation is to reveal the physiological and physical origins and consequences of the NPQ response in diatoms during short-term transitions to excessive irradiation. The investigation involves diatom species from different originating light environs to highlight the diversity of diatom NPQ and to facilitate the detection of core mechanisms common among the diatoms as a group. A chiefly spectroscopic approach was used to investigate NPQ in diatom cells. Prime methodologies include: the real time monitoring of PSII excitation and de-excitation pathways via PAM fluorometry and pigment interconversion via transient absorbance measurements, the collection of cryogenic absorbance spectra to measure pigment energy levels, and the collection of cryogenic fluorescence spectra and room temperature picosecond time resolved fluorescence decay spectra to study excitation energy transfer and dissipation. Chemical inhibitors that target the trans-thylakoid pH gradient, the enzyme responsible for diadinoxanthin de-epoxidation, and photosynthetic electron flow were additionally used to experimentally manipulate the NPQ response. Multifaceted analyses of the NPQ responses from two previously un-photosynthetically characterised species, Nitzschia curvilineata and Navicula sp., were used to identify an excitation pressure relief ‘strategy’ for each species. Three key areas of NPQ were examined: (i) the NPQ activation/deactivation processes, (ii) how NPQ affects the collection, dissipation, and usage of absorbed light energy, and (iii) the interdependence of NPQ and photosynthetic electron flow. It was found that Nitzschia cells regulate excitation pressure via performing a high amplitude, reversible antenna based quenching which is dependent on the de-epoxidation of diadinoxanthin. In Navicula cells excitation pressure could be effectively regulated solely within the PSII reaction centre, whilst antenna based, diadinoxanthin de-epoxidation dependent quenching was implicated to be used as a supplemental, long-lasting source of excitation energy dissipation. These strategies for excitation balance were discussed in the context of resource partitioning under these species’ originating light climates. A more detailed investigation of the NPQ response in Nitzschia was used to develop a comprehensive model describing the mechanism for antenna centred non-photochemical quenching in this species. The experimental evidence was strongly supportive of a mechanism whereby: an acidic lumen triggers the diadinoxanthin de-epoxidation and protonation mediated aggregation of light harvesting complexes leading to the formation of quencher chlorophyll a-chlorophyll a dimers with short-lived excited states; quenching relaxes when a rise in lumen pH triggers the dispersal of light harvesting complex aggregates via deprotonation events and the input of diadinoxanthin. This model may also be applicable for describing antenna based NPQ in other diatom species.

Myosin Regulatory Light Chain Phosphorylation and Its Effect on the Contractile Economy of Mouse Fast Muscle

Activated by elevations in myoplasmic calcium concentration, myosin light chain kinase (skMLCK) phosphorylates the regulatory light chains (RLCs) of fast muscle myosin. This covalent modification potentiates force production, but requires an investment of ATP. Our objective was to investigate the effect of RLC phosphorylation on the contractile economy (mechanical output:metabolic input) of fast twitch skeletal muscle. Extensor digitorum longus muscles isolated from Wildtype and skMLCK-/- mice mounted in vitro (25°C) were subjected to repetitive low-frequency stimulation (10Hz,15s) known to cause activation of skMLCK, and staircase potentiation of force. With a 3-fold increase in RLC phosphate content, Wildtype generated 44% more force than skMLCK-/- muscles over the stimulation period (P = .002), without an accompanied increase in energy cost (P = .449). Overall, the contractile economy of Wildtype muscles, with an intact RLC phosphorylation mechanism, was 73% greater than skMLCK /- muscles (P = .043), demonstrating an important physiological function of skMLCK during repetitive contractile activity.

Letter to S.D. Woodruff in order to give Mr. Woodruff and idea of how fast the interest payments are made to the company

Letter (incomplete) to S.D. Woodruff in order to give Mr. Woodruff an idea of how fast the interest payments are made to the company. The letter is slightly water damaged. The text is affected, but legible. The signature is missing. Feb. 8, 1883.

How fast and how often: the pharmacokinetics of drug use are decisive in addiction

How much, how often and how fast a drug reaches the brain determine the behavioural and neuroplastic changes associated with the addiction process. Despite the critical nature of these variables, the drug addiction field often ignores pharmacokinetic issues, which we argue can lead to false conclusions. First, we review the clinical data demonstrating the importance of the speed of drug onset and of intermittent patterns of drug intake in psychostimulant drug addiction. This is followed by a review of the preclinical literature demonstrating that pharmacokinetic variables play a decisive role in determining behavioural and neurobiological outcomes in animal models of addiction. This literature includes recent data highlighting the importance of intermittent, ‘spiking’ brain levels of drug in producing an increase in the motivation to take drug over time. Rapid drug onset and intermittent drug exposure both appear to push the addiction process forward most effectively. This has significant implications for refining animal models of addiction and for better understanding the neuroadaptations that are critical for the disorder.

Fast imaging of laser-blow-off plume:Lateral confinement in ambient environment

The dynamics of plasma plume, formed by the laser-blow-off of multicomponent LiF-C thin film under various ambient pressures ranging from high vacuum to argon pressure of 3 Torr, has been studied using fast imaging technique. In vacuum, the plume has ellipsoidal shape. With the increase in the ambient pressure, sharp plume boundary is developed showing a focusing-like confinement in the lateral space behavior in the front end, which persists for long times. At higher ambient pressure (> 10−1 Torr ), structures are developed in the plasma plume due to hydrodynamic instability/turbulences.