New measurements of the mechanical loss factors of hydroxide-catalysis bonds have been made and these have been found to be significantly lower than previously reported. We provide the first estimate ...for the resulting thermal noise limitation for a practical test mass geometry for next generation gravitational wave detectors.
The nature of the interaction between low-excitation gas filaments at ~10 super(4) K, seen in optical line emission, and diffuse X-ray emitting coronal gas at ~10 super(7) K in the centers of galaxy ...clusters remains a puzzle. The presence of a strong, empirical correlation between the two gas phases is indicative of a fundamental relationship between them, though as yet of undetermined cause. The cooler filaments, originally thought to have condensed from the hot gas, could also arise from a merger or the disturbance of cool circumnuclear gas by nuclear activity. Here, we have searched for intrinsic line emission polarization in cool core galaxy clusters as a diagnostic of fundamental transport processes. Drawing on developments in solar astrophysics, direct energetic particle impact induced polarization holds the promise to definitively determine the role of collisional processes such as thermal conduction in the ISM physics of galaxy clusters, while providing insight into other highly anisotropic excitation mechanisms such as shocks, intense radiation fields, and suprathermal particles. Under certain physical conditions, theoretical calculations predict of the order of 10% polarization. Our observations of the filaments in four nearby cool core clusters place stringent upper limits (lap0.1%) on the presence of emission line polarization, requiring that if thermal conduction is operative, the thermal gradients are not in the saturated regime. This limit is consistent with theoretical models of the thermal structure of filament interfaces.
Four different corn, soybean, and wheat cropping systems were established in small replicated plots and simultaneously in larger (4-hectare) unreplicated fields. Each system was subject to distinct ...tillage practices, fertility programs, and methods of pest control, based on methods currently in use on farms in the Mid-Atlantic region of the United States. Ground-dwelling arthropods (mostly Carabidae and spiders) were sampled during the fourth and sixth growing season after the establishment of the plots, and foliar insects (pest and beneficial) and pest damage were sampled on corn in the sixth growing season. Overall, beneficial arthropod populations were lowest and corn pest insect populations (especially Western corn rootworms, Diabrotica virgifera virgifera LeConte) were highest in the simplest, most intensively managed continuous corn system, which had annual use of soil insecticides. Generally ground-dwelling species were higher in soybeans than in corn, and in no-till than in deep-tilled crops. Growers wishing to enhance populations of beneficial insects should consider predominantly no-till cropping systems with several different crops in the rotation and minimal insecticide use. For both ground and foliar sampling, patterns of abundance among systems and crops in the small replicated plots generally followed those observed in the large fields, but numbers of spiders and carabids collected per pitfall trap were generally much higher in the large fields.
Purpose.
To compare 2 methods of wound closure—metallic staples or 3–0 undyed vicryl—according to postoperative wound complication rates.
Methods.
Patients who underwent surgery for proximal femoral ...fractures were randomised to have wound closure with metallic staples or with subcuticular vicryl suture. Wounds were regularly examined postoperatively and only those with positive wound swabs were regarded as wound infections.
Results.
Five infections and one superficial wound dehiscence occurred in the patients who had wound closure with metallic staples. The complication rate was significantly higher for this group compared with the group who had wound closure with subcuticular vicryl suture (p<0.025).
Conclusion.
Superficial wound complication rates are higher for wounds closed with metallic staples compared to wounds closed with subcuticular vicryl.
To assess the importance of brain cytochrome P450 (P450) activity in μ opioid analgesic action, we generated a mutant mouse with brain neuron-specific reductions in P450 activity; these mice showed ...highly attenuated morphine antinociception compared with controls. Pharmacological inhibition of brain P450 arachidonate epoxygenases also blocked morphine antinociception in mice and rats. Our findings indicate that a neuronal P450 epoxygenase mediates the pain-relieving properties of morphine.
Improgan is an analog of the H
2 antagonist cimetidine that does not act on known histamine receptors, but induces highly effective analgesia in rodents following intracerebroventricular (icv) ...administration. Since the mechanism of action of this compound remains unknown, improgan analgesia was characterized presently with the tail immersion nociceptive test in mutant mice lacking either the
μ (exon 1 of MOR-1),
δ (exon 2 of DOR-1) or
κ (exon 3 of KOR-1) opioid receptor. Improgan (30 μg, icv) induced reversible, maximal analgesia in both sexes of all three genotypes (+/+, +/− and −/−) of MOR-1 mutant mice 10 and 20 min after administration, whereas morphine analgesia was reduced (+/−) or abolished (−/−) in these subjects. In DOR-1 mutant mice, improgan was equally effective in all three genotypes, despite the reduction (+/−) or complete loss (−/−) of
δ opioid receptor (
3H-
d-Pen
2,
d-Pen
5enkephalin, DPDPE) binding. Similarly, improgan analgesia was equivalent in all three genotypes of KOR-1 mutant mice, whereas
κ-mediated analgesia (U50,488) and
κ opioid (
3H-U69,593) binding were abolished in the homozygous (−/−) mice. These studies demonstrate that improgan analgesia does not require intact MOR-1, DOR-1, or KOR-1 genes, and support the hypothesis that improgan-like analgesics act in the CNS by non-opioid mechanisms.
The hyperthermophilic Archaea Sulfolobus solfataricus grows optimally above 80 degrees C and metabolizes glucose by a non-phosphorylative variant of the Entner-Doudoroff pathway. In this pathway ...glucose dehydrogenase and gluconate dehydratase catalyze the oxidation of glucose to gluconate and the subsequent dehydration of gluconate to D-2-keto-3-deoxygluconate (KDG). KDG aldolase (KDGA) then catalyzes the cleavage of KDG to D-glyceraldehyde and pyruvate. It has recently been shown that all the enzymes of this pathway exhibit a catalytic promiscuity that also enables them to be used for the metabolism of galactose. This phenomenon, known as metabolic pathway promiscuity, depends crucially on the ability of KDGA to cleave KDG and D-2-keto-3-deoxygalactonate (KDGal), in both cases producing pyruvate and D-glyceraldehyde. In turn, the aldolase exhibits a remarkable lack of stereoselectivity in the condensation reaction of pyruvate and D-glyceraldehyde, forming a mixture of KDG and KDGal. We now report the structure of KDGA, determined by multiwavelength anomalous diffraction phasing, and confirm that it is a member of the tetrameric N-acetylneuraminate lyase superfamily of Schiff base-forming aldolases. Furthermore, by soaking crystals of the aldolase at more than 80 degrees C below its temperature activity optimum, we have been able to trap Schiff base complexes of the natural substrates pyruvate, KDG, KDGal, and pyruvate plus D-glyceraldehyde, which have allowed rationalization of the structural basis of promiscuous substrate recognition and catalysis. It is proposed that the active site of the enzyme is rigid to keep its thermostability but incorporates extra functionality to be promiscuous.
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