The Simons Observatory: Cryogenic half wave plate rotation mechanism for the small aperture telescopes.

We present the requirements, design, and evaluation of the cryogenic continuously rotating half-wave plate (CHWP) for the Simons Observatory (SO). SO is a cosmic microwave background polarization experiment at Parque Astronómico de Atacama in northern Chile that covers a wide range of angular scales using both small (⌀0.42 m) and large (⌀6 m) aperture telescopes. In particular, the small aperture telescopes (SATs) focus on large angular scales for primordial B-mode polarization. To this end, the SATs employ a CHWP to modulate the polarization of the incident light at 8 Hz, suppressing atmospheric 1/f noise and mitigating systematic uncertainties that would otherwise arise due to the differential response of detectors sensitive to orthogonal polarizations. The CHWP consists of a 505 mm diameter achromatic sapphire HWP and a cryogenic rotation mechanism, both of which are cooled down to ∼50 K to reduce detector thermal loading. Under normal operation, the HWP is suspended by a superconducting magnetic bearing and rotates with a constant 2 Hz frequency, controlled by an electromagnetic synchronous motor. We find that the number of superconductors and the number of magnets that make up the superconducting magnetic bearing are important design parameters, especially for the rotation mechanism's vibration performance. The rotation angle is detected through an angular encoder with a noise level of 0.07 µrad s. During a cooldown process, the rotor is held in place by a grip-and-release mechanism that serves as both an alignment device and a thermal path. In this paper, we provide an overview of the SO SAT CHWP: its requirements, hardware design, and laboratory performance.

Activation of JNK in rat heart by exercise: effect of training.

The purpose of the study was to determine whether exercise would activate JNK in the heart and whether chronic exercise training would alter the response. Untrained rats were familiarized with the treadmill and assigned to one of four groups: low intensity (LI), 10 min, 0%, 15 m/min; medium intensity (MI), 10 min, 0%, 33 m/min; high intensity (HI), 10 min, 25%, 33 m/min; long duration (LD), 30 min, 0%, 15 m/min. Another cohort of rats was subjected to a progressive 6 wk high-intensity training protocol that produced a 12% increase in heart mass. In untrained rats, JNK activity was LI: 1.5 (fold nonrun control), MI: 2.0, HI: 2.5, LD: 1.25 immediately after a single bout of exercise. In trained rats, no activation of JNK above baseline was detected after either a 10-min or 1-h bout of exercise. We concluded that treadmill exercise activates JNK in the rat heart in an intensity-dependent manner and that chronic training abrogates the myocardial JNK response to a bout of exercise.

Development of a clinical assessment of quality of movement for unilateral upper-limb function.

Eleven subjects with cerebral palsy were assessed both with the Melbourne Assessment and by four clinical experts. Comparison of their assessment ratings revealed that the Melbourne Assessment was strongly related to the clinical judgement of the experts. A further 20 subjects were administered the Melbourne Assessment and two occupational therapists scored each subject's performance from videotaped assessments with substantial inter-rater reliability (0.68); intra-rater agreement after two weeks was 0.80. The Melbourne Assessment may provide a satisfactory objective measure of the quality of upper-limb function.

Selective thromboxane synthetase inhibitors. 3. 1H-imidazol-1-yl-substituted benzo[b]furan-, benzo[b]thiophene-, and indole-2- and -3-carboxylic acids.

The preparation of a series of 1H-imidazol-1-yl-substituted benzo[b]furan-, benzo[b]thiophene-, and indolecarboxylic acids is described. Most of the compounds were potent inhibitors of TxA2 synthetase in vitro, and the distance between the imidazole and carboxylic acid groups was found to be important for optimal potency. The most potent compound in vivo was 6-(1H-imidazol-1-ylmethyl)-3-methylbenzo[b]thiophene-2-carboxylic acid (71), which, in conscious dogs, showed a similar profile of activity to that of dazoxiben (1).

Selective thromboxane synthetase inhibitors. 4. 2-(1H-imidazol-1-ylmethyl) carboxylic acids of benzo[b]furan, benzo[b]thiophene, indole, and naphthalene.

The preparation of a series of 2-(1H-imidazol-1-ylmethyl)-substituted carboxylic acids of benzo[b]furan, benzo-[b]thiophene, indole, and naphthalene is described. All compounds showed a similar level of activity as TxA2 synthetase inhibitors in vitro, having IC50 values between 1 and 7 X 10(-8) M. In the cases examined, compounds had, at most, only negligible activity against PGI2 synthetase, cyclooxygenase, and steroid 11 beta-hydroxylase. The benzo[b]thiophenes generally showed the greatest potency in vivo, and compounds 72, 73, and 75 caused almost complete inhibition of thromboxane production for 6 h after oral administration of 0.5 mg/kg to conscious dogs. In the case of 73 and 75, thromboxane production was still inhibited by 80% after 24 h.

Selective thromboxane synthetase inhibitors. 2. 3-(1H-imidazol-1-ylmethyl)-2-methyl-1H-indole-1-propanoic acid and analogues.

The preparation of a series of 3-(1H-imidazol-1-ylmethyl)-1H-indole-1-alkanoic acids is described. Several compounds were found to be more potent thromboxane synthetase inhibitors than the corresponding analogues lacking an acidic substituent. In the cases examined, compounds had no significant activity against PGI2 synthetase or cyclooxygenase, and introduction of the carboxylic acid substituent led to a reduction in activity against adrenal steroid 11 beta-hydroxylase. Compound 21 strongly inhibited thromboxane formation after iv administration to anesthetized rabbits and oral administration to conscious dogs. The compound had a long duration of action, and marked inhibition of thromboxane production was observed 15 h after oral administration of 1 mg/kg to conscious dogs.

Selective thromboxane synthetase inhibitors. 1. 1-[(Aryloxy)alkyl]-1H-imidazoles.

1-(2-Phenoxyethyl)-1H-imidazole was found to be an inhibitor of thromboxane (TxA2) synthetase, but it also inhibited the adrenal cytochrome P-450 enzyme steroid 11 beta-hydroxylase. The preparation of a series of analogues is described, and activity against TxA2 synthetase, PGI2 synthetase, cyclooxygenase, and steroid 11 beta-hydroxylase is discussed. Potency against TxA2 synthetase was increased by introduction of a carboxyl group at a suitable distance from the imidazole ring. A distance of 8.1-8.8 A between N-1 of the imidazole and the carboxyl carbon was found to be optimal. Introduction of a carboxyl group also had the effect of reducing activity against steroid 11 beta-hydroxylase. The most potent and selective compound was found to be 4-[2-(1H-imidazol-1-yl) ethoxy]benzoic acid (14).

Acute arterial thrombosis in rabbits: reduced platelet accumulation after treatment with dazoxiben hydrochloride (UK 37,248-01).

1 Acute thrombosis was induced in the carotid arteries of anaesthetized rabbits by local electrical stimulation (1 mA for 2 min) of the vessel wall. Histological findings confirmed the platelet-rich composition of the thrombus. Platelet accumulation at the stimulus site was quantitated with 111Indium-labelling of autologous platelets. 2 In rabbits injected intravenously with either the thromboxane synthetase inhibitor dazoxiben 2 mg/kg or aspirin 10 mg/kg, accumulation of labelled platelets was considerably reduced. Animals which received vehicle injection only, showed no such reduced thrombus formation. 3 In separate experiments in anaesthetized rabbits, the levels of thromboxane B2 (TXB2) and 6-keto-prostaglandin F1 alpha in clotting blood were measured in blood samples taken from animals which had received the above drug treatments. Aspirin markedly reduced the production of both arachidonate metabolites. In contrast, dazoxiben almost totally inhibited TXB2 production but caused a 3.5-fold increase in the levels of 6-keto PGF1 alpha. 4 These findings demonstrate an antithrombotic effect and confirm the mechanistic selectivity of a thromboxane synthetase inhibitor.

Acute arterial thrombosis in rabbits: reduced platelet accumulation after treatment with thromboxane synthetase inhibitor dazoxiben hydrochloride, (UK-37, 248-01).

Acute thrombosis was induced in the carotid arteries of anaesthetised rabbits by local electrical stimulation (1mA for 2 min) of the vessel wall. Histological findings confirmed the platelet-rich composition of the thrombus. Platelet accumulation at the stimulus site was quantitated with "'Indium-labelling of autologous platelets. In rabbits injected intravenously with either 2 mg/kg dazoxiben or 10 mg/kg aspirin, accumulation of labelled platelets was considerably reduced. Animals which received vehicle injection only, showed no such reduced thrombus formation. In separate experiments in anaesthetised rabbits, the levels of TxB2 and 6KPGF1 alpha in clotting blood were measured in blood samples taken from animals which had received the above drug treatments. Aspirin markedly reduced the production of both arachidonate metabolites. In contrast, dazoxiben almost totally inhibited TxB2 production but caused a 3.5 fold increase in the levels of 6KPGF1 alpha. These findings demonstrate an anti-thrombotic effect and confirm the mechanistic selectivity of a thromboxane synthetase inhibitor.

Cerebrovasodilatation through selective inhibition of the enzyme carbonic anhydrase. 3. 5-(Arylthio)-, 5-(arylsulfinyl)-, and 5-(arylsulfonyl)thiophene-2-sulfonamides.

A series of 5-(arylthio)-, 5-(arylsulfinyl)-, and 5-(arylsulfonyl)thiophene-2-sulfonamides is described and anticonvulsant activities are listed for the compounds. In most cases, the sulfones had the highest activity and the sulfides the least. Sulfones with 3- or 4-halo substituents generally had the highest activity, and one analogue, 5-[(4-fluorophenyl)sulfonyl]thiophene-2-sulfonamide (51, UK-17022), had an anticonvulsant ED50 fo 2 mg/kg when administered orally to mice. Compound 51 selectively increased cerebral blood flow in animals without an unacceptable level of diuresis.

3-(1-imidazolylmethyl) indoles: potent and selective inhibitors of human blood platelet thromboxane synthetase.

Several 3-(1-imidazolylmethyl) indoles were tested for inhibition of the microsomal enzymes which catalyse the biosynthesis of thromboxane A2, prostaglandin I2, and prostaglandin endoperoxides. These products were measured by bioassay to assess levels of enzyme activity. The highest activity against human blood platelet thromboxane A2-synthetase was obtained with 2-cyclopropyl-3(1-imidazolylmethyl) indole (IC50 1 x 10(-10) M). This compound also exhibited the highest activity against pig aorta prostaglandin I2-synthetase (IC50 8.4 x 10(-7) M). Of much more potential therapeutic interest, 2-isopropyl-3-(1-imidazolylmethyl) indole showed almost complete selectivity against thromboxane A2-synthetase. Both compounds exhibited IC50's of 2 x 10(-8) M against the latter enzyme but showed only weak effects (IC50's greater than 10(-4) M) against prostaglandin I2-synthetase and ram seminal vesicle PGH2-synthetase.

Piroxicam, a structurally novel anti-inflammatory compound. Mode of prostaglandin synthesis inhibition.

Piroxicam is a potent inhibitor of prostaglandin biosynthesis. Experiments utilizing cell culture and microsomes derived from various sources have demonstrated that piroxicam is a selective inhibitor of the cyclooxygenase step of arachidonic acid metabolism. Little blocking activity is observed at the phospholipase, thromboxane or prostacyclin synthetase, and arachidonic acid lipoxygenase steps.

Cerebrovasodilatation through selective inhibition of the enzyme carbonic anhydrase. 2. Imidazo[2,1-b]thiadiazole and imidazo[2,1-b]thiazolesulfonamides.

A series of imidazo[2,1-b]thiadiazole and imidazo[2,1-b]thiazolesulfonamide carbonic anhydrase inhibitors is described and their anticonvulsant activities are listed. Many of the compounds have the same degree of ionization as acetazolamide and methazolamide, but their higher lipophilicity means that they are more able to penetrate into the central nervous system. One compound, 6-tert-butyl-2-sulfamoylimidazo[2,1-b]-1,3,4-thiadiazole (8, UK-15,454) had an anticonvulsant ED50 of 2.6 mg/kg when administered orally to mice. 8 selectively increased cerebral blood flow in animals without producing a high level of metabolic acidosis.