Conformational properties of Eu(III) complexes of 3,3′; 5,3″-polymethylene bridged derivatives of 2,2′; 6,2″-terpyridine

The complex [Eu(tpy)₃](ClO₄)₃ where TPY=2,2′; 6,2″-terpyridine, has been prepared and reexamined. The complex appears to be stable in acetonitrile solution with respect to decomplexation of the ligands but the addition of water does cause partial replacement of tpy. Analogous complexes have been prepared with 3,3′; 5,3″-polymethylene bridged derivatives of tpy having two or three carbons in the bridge. The bridging enforces a cisoid geometry of the ligand and prohibits its replacement by added water. An X-ray determination was carried out for [Eu(3b)₃](ClO₄)₃, where 3b=3,3′; 5,3″-dimethylene tpy, which crystallizes in the monoclinic space group P2₁/c with a=11.908(4), b=15.768(5), c=29.513(9) Å, β=93.60(2)°, μ=13.5 cm⁻¹ and Z=4. The complex forms a tricapped trigonal prism with each of the ligands adopting the same dl conformation. Variable temperature NMR analysis of the bridged ligand complexes indicates that conformational inversion of the bound ligand is not a concerted process and barriers for inversion of individual methylene units can be estimated from coalescence of the signals from the geminal methylene protons. The luminescence properties of the bridged tpy complexes are similar to the parent unbridged system.     

Writing failure: knowledge production,temporalities, ethics,and traces

This volume follows failures out into the world, exploring how they unfold ethnographically. Taking a longer view shows how objects, narratives, and diagnoses of failures may be crafted, acted on, suffered, resisted – unmade or recomposed. Thus while tropes and diagnoses of failure can temporarily (re)organize, narrate, and stabilize the world, the kinds of failures explored here also indicate a mode of uncontainable excess that refuses the boundedness of knowledge objects, temporalities, and spaces. This volume offers three main interventions. The first concerns knowledge production: how objects of failure are crafted through selective ways of knowing that occlude both other modes of apprehension at different scales and failure's many affective valences. The second thinks through the knotted temporalities – whether pasts, futures, suspended presents, or repetition and sedimentation – that make and are made by failure. Finally, writing about unfurling failures requires careful attention to non-linear reverberations and traces as well as to open-ended and mobile narratives that produce different social and material effects.     

Malignant cerebral glioma--I: Survival,disability, and morbidity after radiotherapy.

OBJECTIVE: To describe survival, disability, and morbidity after radiotherapy for malignant glioma. DESIGN: Two year prospective study with home interviews with patients and relatives. SETTING: Seven neurosurgical and radiotherapy centres in London. SUBJECTS: 105 patients aged 21 to 75: 59 had biopsy; 46 had partial macroscopic resection; 92 received radiotherapy; and 13 received steroids alone. MAIN OUTCOME MEASURES: Survival, time free from disability, and changes in disability after treatment. RESULTS: Six and 12 month survival for radiotherapy patients was 70% and 39%, respectively. Age, World Health Organisation clinical performance status, extent of surgery, and history of seizures before diagnosis each influenced survival. The Medical Research Council prognostic index was also significantly related to survival. Multivariate analysis showed that initial clinical performance status was the most important component of the index. Most (80%; 49/61) patients with a clinical performance status of 0, 1, or 2 lived at least six months before becoming permanently disabled. Most patients who had initially had a good clinical performance status (0-2) and who were alive six months after radiotherapy (68%; 36/52), however, had experienced either clinical deterioration or severe tiredness after treatment. In 17% (9/52) of these some permanent loss of function remained. These adverse effects were associated with increasing radiotherapy dose. Severely disabled patients (clinical performance status 3 or 4) gained little benefit. CONCLUSION: Severely disabled patients gain little physical benefit from radiotherapy, whereas those not so disabled may experience considerable adverse effects.     

The transposable element mariner can excise in non-drosophilid insects

Plasmid-based excision assays performed in embryos of two non-drosophilid species using the mariner transposable element from Drosophila mauritiana resulted in empty excision sites identical to those observed after the excision of mariner from D. mauritiana chromosomes. In the presence of the autonomous mariner element Mos1, excision products were recovered from D. melanogaster, D. mauritiana and the blowfly Lucilia cuprina. When a hsp82 heat shock promoter-Mos1 construct was used to supply mariner transposase, excision products were also recovered from the Queensland fruitfly Bactrocera tryoni. Analysis of DNA sequences at empty excision sites led us to hypothesise that the mariner excision/repair process involves the formation of a heteroduplex at the excision breakpoint. The success of these assays suggests that they will provide a valuable tool for assessing the ability of mariner and mariner-like elements to function in non-drosophilid insects and for investigating the basic mechanisms of mariner excision and repair.     

Maintenance of transposable element copy number in natural populations of Drosophila melanogaster and D. simulans

To investigate the main forces controlling the containment of transposable elements (TE) in natural populations, we analyzed the copia, mdg1, and 412 elements in various populations of Drosophila melanogaster and D. simulans. A lower proportion of insertion sites on the X chromosome in comparison with the autosomes suggests that selection against the detrimental effects of TE insertions is the major force containing TE copies in populations of Drosophila. This selection effect hypothesis is strengthened by the absence of the negative correlation between recombination rate and TE copy number along the chromosomes, which was expected under the alternative ectopic exchange model (selection against the deleterious rearrangements promoted by recombination between TE insertions). A cline in 412 copy number in relation to latitude was observed among the natural populations of D. simulans, with very high numbers existing in some local populations (around 60 copies in a sample from Canberra, Australia). An apparent absence of selection effects in this Canberra sample and a value of transposition rate equal to 1–2 × 10^-3 whatever the population and its copy number agree with the idea of recent but temporarily drastic TE movements in local populations. The high values of transposition rate in D. simulans clearly disfavor the hypothesis that the low amount of transposable elements in this species could result from a low transposition rate. This revised version was published online in August 2006 with corrections to the Cover Date.     

Functional morphology of the branchial basket of ascidia paratropa (Tunicata,Ascidiacea)

Summary The filtering surface of the branchial basket of Ascidia paratropa (Huntsman, 1912) consists of two adjacent and connected sheets. The stigmatal surface is loosely folded. The secondary gill screen, composed of ciliated longitudinal vessels with primary and secondary papillae, is connected to the stigmatal surface on the inside of the branchial basket. Continuous mucus secretion results in a net with elastic and adhesive properties, and a pore size of less than 0.5 m in its longest dimension. Net production cannot be interrupted by external mechanical stimuli. The net is usually supported by and transported across the secondary screen, forming a filtering surface that parallels the undulations of the stigmatal surface; however, localized muscular activity of the dorsal laminar fold and longitudinal vessels are also involved in mucous net transport. Squirts occur more frequently than in many species. At these times the net is transported as a flat sheet, independent of the secondary screen. Squiring does not interrupt continuous feeding activity.     

Alignment of clonedamiE gene ofPseudomonas aeruginosa with theN-terminal sequence of amidase

A restriction enzyme map was constructed for 5.1-kb fragment of Pseudomonas aeruginosa DNA inserted into plasmid pBR322. Restriction enzyme sites were matched to the N-terminal amino acid sequence of amidase to obtain alignment of the amiE gene within the cloned fragment.     

Comparison of metformin and chlorpropamide in non-obese,maturity-onset diabetics uncontrolled by diet.

The clinical effectiveness of metformin was compared with that of chlorpropamide in closely similar groups of 216 non-obese patients recently diagnosed as cases of maturity-onset diabetes that could not be controlled by diet. The incidences of primary and secondary drug failures in each group and the numbers of patients satisfactorily maintained on each of the hypoglycaemic agents throughout the first year proved remarkably similar. In 61 of the successfully treated patients who were studied by crossover to the other drug and observed for a further year the mean blood glucose concentrations at the end of the year were roughly comparable, but the mean weight response was a small loss of 1.5 +/- 3.8 kg with metformin but a gain of 4.6 +/- 3.9 kg with chlorpropamide. Thus for non-obese, maturity-onset diabetics whose disease cannot be controlled by diet and who require oral treatment sulphonylureas and biguanides are equally effective, the choice depending on whether the patient is underweight and the severity of symptoms.     

Myofilament lengths of cat skeletal muscle: theoretical considerations and functional implications.

The cat is the primary model for neuromuscular research. However, sarcomere geometry, in particular thin-myofilament lengths of cat skeletal muscles, is not known, thus preventing adequate muscle modeling on the sarcomere level. The purpose of this study was to determine thin-myofilament lengths in cat skeletal muscle. It was found that average thin-myofilament lengths of cat tibialis anterior muscles (1.12 microns) were larger than the average values reported for frog (approximately 0.95 microns), rat (1.09 microns), and rabbit muscles (1.09 microns) and were smaller than the values reported for monkey (1.16 microns) and human skeletal muscles (1.27 microns). According to the cross-bridge theory of muscular contraction, this result implies that the range of sarcomere length on the ascending limb of the force-length relation for cat muscle is between those of frog, rat, and rabbit on the one side and monkey and human on the other side. It is speculated that the differences in thin-myofilament lengths of different animals are related to the functional demands of these muscles in everyday movement tasks. Isolated experimental observations appear to support this speculation.