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Forkhead proteins, and FoxO1 in particular, play a significant role in regulating whole body energy metabolism. Glucose homeostasis is achieved by adjusting endogenous glucose production as well as glucose uptake by peripheral tissues in response to insulin. In the fasted state, the liver is primarily responsible for maintaining glucose levels, with FoxO1 playing a key role in promoting the expression of gluconeogenic enzymes. Following feeding, pancreatic beta cells secrete insulin, which promotes the uptake of glucose by peripheral tissues including skeletal muscle and adipose tissue, and can in part suppress gluconeogenic enzyme expression in the liver. In addition to directly regulating metabolism, FoxO1 also plays a role in the formation of both adipose tissue and skeletal muscle, two major organs that are critical for maintaining energy homeostasis. The importance of FoxO1 in energy homeostasis is particularly striking under conditions of metabolic dysfunction or insulin resistance. In obese or diabetic states, FoxO1-dependent gene expression promotes some of the deleterious characteristics associated with these conditions, including hyperglycemia and glucose intolerance. In addition, the increase in pancreatic beta cell mass that normally occurs in response to a rise in insulin demand is blunted by nuclear FoxO1 expression. However, under these same pathophysiological conditions, FoxO1 expression may help drive the expression of genes involved in combating oxidative stress, thereby preserving cellular function. FoxO1 may also be involved in promoting the switch from carbohydrate to fatty acid as the major energy source during starvation.

Objective Smoking increases the risk for influenza and pneumococcal disease, but vaccination uptake is lower among smokers than non-smokers. We therefore aimed to determine reasons for not complying with vaccination among smokers and non-smokers. Method In 2005 a self-administered questionnaire was sent to a random sample of Dutch patients ( n = 4,000) assessing medical, social and behavioural determinants. Independent factors associated with not complying with influenza and pneumococcal vaccination among smokers and non-smokers were assessed by multivariate logistic regression analysis. Results In all, 1,725 of 4,000 patients returned the questionnaire (response rate: 43%), 426 (25%) were smokers. Among smokers self-reported flu vaccine uptake was 42% and among non-smokers 52% among both only 0,2% received both vaccines. Most important predictors of not complying in smokers and non-smokers were patient's beliefs not to be susceptible to disease (odds ratio (OR) 4.0, 95% confidence interval (CI): 2.0, 8.0 and OR 2.8, CI: 2.0, 3.9), finding it difficult to go to the GP for vaccination (OR 2.5, CI: 1.3, 4.8 and OR 1.8, CI: 1.3, 2.6) and being against vaccination (OR 2.4 CI: 1.3, 4.4 and OR 1.8, CI: 1.3, 2.6), respectively. Conclusion There are no substantial differences in determinants associated with not complying with influenza and pneumococcal vaccination between smokers and non-smokers but there is a trend towards stronger associations in smokers.

Prof. Dr. Pieter Hendrik (Piet) Nienhuis worked for almost 40 years in all aspects of aquatic ecology and environmental science and retired on 31 October 2003. He can be characterised as a distinguished scientist, shaped in an applied estuarine and aquatic research ambience of the former Delta Institute for Hydrobiological Research (DIHO) in Yerseke in the Netherlands. His appointment as a full professor at the Radboud University Nijmegen offered him a challenging step from monodisciplinarity in ecology, via multidisciplinarity in the application of ecological knowledge in river science to interdisciplinarity in environmental science and management. This paper describes his education, teaching activities, research, scientific publications, science management, and significance for various scientific disciplines. He made important contributions to biosystematics of angiosperms and algae, the ecology of seagrasses, nutrient cycling and eutrophication in estuarine ecosystems, and the integrated modelling of the ecological functioning of estuaries. Subsequently, he paid much attention to environmental problems in river basins, ecological rehabilitation and sustainable development. His work influenced the view of ecologists, aquatic scientists and water managers in the Netherlands as well as abroad, in particular regarding the drawbacks of compartmentalization of the estuaries and the importance of connectivity and morphodynamics in river systems. In hindsight, it appears as a logical line that he gradually moved from estuarine ecological research that became increasingly driven by societal and environmental problems to the field of environmental science and management. [KEYWORDS: coastal zone management ; estuarine ecology ; environmental sciences ; interdisciplinary research ; river basin management ; river ecology]

Over the past five years evidence has mounted that long-duration (> 2 s) gamma-ray bursts (GRBs)--the most brilliant of all astronomical explosions--signal the collapse of massive stars in our Universe. This evidence was originally based on the probable association of one unusual GRB with a supernova, but now includes the association of GRBs with regions of massive star formation in distant galaxies, the appearance of supernova-like 'bumps' in the optical afterglow light curves of several bursts and lines of freshly synthesized elements in the spectra of a few X-ray afterglows. These observations support, but do not yet conclusively demonstrate, the idea that long-duration GRBs are associated with the deaths of massive stars, presumably arising from core collapse. Here we report evidence that a very energetic supernova (a hypernova) was temporally and spatially coincident with a GRB at redshift z = 0.1685. The timing of the supernova indicates that it exploded within a few days of the GRB, strongly suggesting that core-collapse events can give rise to GRBs, thereby favouring the 'collapsar' model., 19 pages, 3 figures

The Faint Sky Variability Survey is aimed at finding photometric and/or astrometric variable objects in the brightness range between 16, Comment: Accepted by MNRAS, 8 pages, 6 figure + 3 as JPEGs

Supersoft X-ray sources (hereafter SSS) are a class of luminous (bolometric luminosity ~ 1037 − 1038 erg s−1) objects with a characteristic radiation temperature of 30 to 60 eV (Hasinger 1994; Kahabka & Trümper 1996). The most popular model for SSS is that they are massive white dwarfs steadily burning nuclear fuel accreted from a more massive binary companion at a rate near or above the Eddington limit (van den Heuvel et al. 1992).

A flower specific cDNA, tgas118, has been isolated after differential screening of a gib-1 anther cDNA library of Lycopersicon esculentum. The corresponding mRNA was present in all tissues analysed. Northern blot analysis revealed that in wild-type tomato the gene was predominantly expressed throughout flower development, while in the gibberellin (GA)-deficient mutant of tomato (gib-1) the abundance declined. Treatment of the mutant with GA resulted in an accumulation of the tgas118 mRNA within hours in leaf and bud tissues. In the leaf, GA 1 , GA3 and GA g were effective in enhancing the expression while GA4 was not. In addition to GA, wounding and dehydration also increased the accumulation of tgas118 mRNA in leaf tissue. In situ hybridization showed that application of 50 ng GA3 bud -1 induced a similar spatial expression of the tgas118 mRNA in gib-1 buds 24 h post treatment to that found in wild-type flower buds. The deduced TGAS118 protein displays up to 77% similarity with defensins and as its expression is up-regulated by stimuli such as wounding it is proposed that it may play a role in protection against pathogens.

To study the role of translocation of gibberellin (GA) intermediates or bioactive GAs from other plant parts to buds during early flower development in tomato (Solanum lycopersicon), the effect of grafting and paclobutrazol (PAC) treatment on the expression of tgas 100 and tgas 118, two GA-regulated mRNAs, was analysed. Both mRNAs accumulated in a dose-dependent fashion. Application of 0.5 ng GA 3 per bud to developmentally arrested flower buds of a GA-deficient mutant of tomato (gib-1) induced tgas 100 expression, while the tgas 118 abundance increased. For obtaining normal flower development through anthesis in the mutant, a single GA 3 treatment was required of at least 5 ng GA, per bud. In wild-type flower buds, PAC decreased the abundance of tgas 100 and tgas 118 mRNAs either when PAC was sprayed on whole plants or directly applied to buds. When only the wild-type buds were treated with PAC, the expression profiles characteristic for untreated buds were not restored by translocation of endogenous GAs. Grafting of gib-1 scions onto wild-type donor plants did not result in normal flower development or expression profiles like in wild-type buds. We conclude that the role of GA transport in early flower development of tomato is negligible and that the GAs required for development have to be synthesized in the flower bud itself.

After differential screening we isolated cDNA clones encoding a histone H1 (leH1) and three variants of histone H2B (leH2B-1, -2 and -3) from the gibberellin (GA)-deficient mutant of tomato (gib-1). The deduced polypeptide of leH1 is 271 amino acids long and exhibits the typical tripartite structure of histones H1. The full-length cDNA clone leH2B-1 encodes for a protein of 142 amino residues and shows the tripartite organization of histones H2B. The histones leH1 and leH2B, which show no tissue specificity, are developmentally expressed in the leaf. The mRNA accumulation was higher in organs which contain meristematic tissue and/or which have a high proportion of actively cycling cells. In the leaf of the gib-1 mutant we demonstrated GA-enhanced histone leH1 and leH2B expression which was not observed in the wild type. GAs of the early-13-hydroxylated pathway (GA1 and GA3) caused most enhanced transcription compared to GAs of the early-non-hydroxylation pathway (GA4 and GA9). Application of GA to the mutant increased histone expression that could correlate with enhanced DNA replication in leaf tissue. Increased chromosome replication may indicate that there is a higher rate of cell division and/or increase of endopolyploidy which both may be dependent on cell elongation induced by GAs.

The millisecond pulsar in a triple system (PSR J0337+1715, recently discovered by Ransom et al.) is an unusual neutron star with two orbiting white dwarfs. The existence of such a system in the Galactic field poses new challenges to stellar astrophysics for understanding evolution, interactions and mass-transfer in close multiple stellar systems. In addition, this system provides the first precise confirmation for a very wide-orbit system of the white dwarf mass-orbital period relation. Here we present a self-consistent, semi-analytical solution to the formation of PSR J0337+1715. Our model constrains the peculiar velocity of the system to be less than 160 km/s and brings novel insight to, for example, common envelope evolution in a triple system, for which we find evidence for in-spiral of both outer stars. Finally, we briefly discuss our scenario in relation to alternative models., Comment: ApJ Letters, in press (6 pages, 3 figures, 1 table)

Item does not contain fulltext Monochorionic dizygous twins are probably more frequent than considered previously as many cases remain unrecognized, especially when the children have the same sex. Here we present a pair of dizygous, sex-discordant monochorionic twins who were conceived after artificial insemination. Histological examination of the placenta and extensive genetic studies of the healthy boy and girl clearly proved that they indeed were monochorionic dizygous twins with a fully joined blood circulation. We conclude that when counseling parents expecting monochorionic twins of discordant sex, not only a disorder of sexual differentiation in one of the twins should be addressed but also the possibility of dizygosity with a completely normal (sexual) development of both children.

Supernovae are classified as type I and type II and further subdivided into Ia, Ib, Ic, II-P, II-L, and IIb. The origin of this observational diversity has not been well understood. The recent nearby supernovae SN 1993J and SN 1994I have provided particularly useful material to clarify the supernova — progenitor connection. For a progenitor of type IIb supernova 1993J, we propose that merging of two stars in a close binary is responsible for the formation of a thin H-rich envelope. As a progenitor of type Ic supernova 1994I, we propose a bare C+O star that has lost both its H and He envelope after a common-envelope phase. By generalizing these scenarios, we show that common-envelope evolution in massive close binary stars leads to various degrees of stripping off of the envelope of a massive star. This naturally leads to an explanation of the origin of type II-L, IIn, IIb, Ib, and Ic in a unified manner. The binary hypothesis to explain the diversity of supernovae can be substantiated with new information on SN IIb 1993J and SN Ic 1994I. Model light curves are compared with observations. Since extensive mass loss is essential for the binary scenario, circumstellar interactions are examined for comparison with X-ray observations.

This work aims to present our current best physical understanding of common-envelope evolution (CEE). We highlight areas of consensus and disagreement, and stress ideas which should point the way forward for progress in this important but long-standing and largely unconquered problem. Unusually for CEE-related work, we mostly try to avoid relying on results from population synthesis or observations, in order to avoid potentially being misled by previous misunderstandings. As far as possible we debate all the relevant issues starting from physics alone, all the way from the evolution of the binary system immediately before CEE begins to the processes which might occur just after the ejection of the envelope. In particular, we include extensive discussion about the energy sources and sinks operating in CEE, and hence examine the foundations of the standard energy formalism. Special attention is also given to comparing the results of hydrodynamic simulations from different groups and to discussing the potential effect of initial conditions on the differences in the outcomes. We compare current numerical techniques for the problem of CEE and also whether more appropriate tools could and should be produced (including new formulations of computational hydrodynamics, and attempts to include 3D processes within 1D codes). Finally we explore new ways to link CEE with observations. We compare previous simulations of CEE to the recent outburst from V1309 Sco, and discuss to what extent post-common-envelope binaries and nebulae can provide information, e.g. from binary eccentricities, which is not currently being fully exploited., Comment: 83 pages (11 chapters, 2 appendixes), 10 figures, Astronomy & Astrophysics Review format. This version contains revisions as a response to community comments

The free fatty acid and total fatty acid profiles in plasma of nine patients with medium-chain acyl-CoA dehydrogenase (MCAD) deficiency, two with very-long-chain acyl-CoA dehydrogenase (VLCAD) deficiency and two with mild-type multiple acyl-CoA dehydrogenase (MAD-m) deficiency, were analyzed by gas chromatography-mass spectrometry. In the plasma of patients with MCAD deficiency we found increases of octanoic acid (8:0), decanoic acid (10:0), 4-decenoic acid (10:1 omega 6), and 4,7-decadienoic acid (10:2 omega 3), all present almost exclusively in free form. The patients with VLCAD deficiency showed increases of mainly 5-tetradecenoic acid (14:1 omega 9) and to a minor extent 5-dodecenoic acid (12:1 omega 7), 5,8-tetradecadienoic acid (14:2 omega 6), and 7,10-hexadecadienoic acid (16:2 omega 6), in both the free and esterified fatty acid fraction. The MAD-m patients showed variable increases of all the unusual fatty acids present in MCAD- and VLCAD-deficient plasma. The 14:1 omega 9, 14:2 omega 6, and 16:2 omega 6 fatty acids were present mainly in the esterified form. Measurement of these fatty acids in plasma by the relatively simple method presented here provides a sensitive and specific aid in the diagnosis of acyl-CoA dehydrogenase deficiency disorders.

Item does not contain fulltext The 17q21.31 microdeletion syndrome is characterised by intellectual disability, epilepsy, distinctive facial dysmorphism, and congenital anomalies. To date, all individuals reported with this syndrome have been simplex patients, resulting from de novo deletions. Here, we report sibling recurrence of the 17q21.31 microdeletion syndrome in two independent families. In both families, the mother was confirmed to be the parent-of-origin for the 17q21.31 deletion. Fluorescence in situ hybridisation analyses in buccal mucosa cells, of the mother of family 1, identified monosomy 17q21.31 in 4/50 nuclei (8%). In mother of family 2, the deletion was identified in 2/60 (3%) metaphase and in 3/100 (3%) interphase nuclei in peripheral lymphocytes, and in 7/100 (7%) interphase nuclei in buccal cells. A common 17q21.31 inversion polymorphism predisposes to non-allelic homologous recombination and hereby to the 17q21.31 microdeletion syndrome. On the basis of the 17q21.31 inversion status of the parents, we calculated that the probability of the second deletion occurring by chance alone was 1/14,438 and 1/4812, respectively. If the inversion status of the parents of a child with the 17q21.31 microdeletion syndrome is unknown, the overall risk of a second child with the 17q21.31 microdeletion is 1/9461. We conclude that the presence of low-level maternal somatic-gonadal mosaicism is associated with the microdeletion recurrence in these families. This suggests that the recurrence risk for parents with a child with a 17q21.31 microdeletion for future pregnancies is higher than by chance alone and testing for mosaicism in the parents might be considered as a helpful tool in the genetic counselling. 01 juli 2012

Background The effects of epidurally administered alfentanil may be due in part to its uptake into the systemic circulation. Therefore we examined the systemic absorption kinetics after epidural injection of alfentanil. Methods Pharmacokinetics were determined using a stable isotope method in ten patients, undergoing lower abdominal surgery under general anesthesia. After epidural injection of 0.68 mg deuterium-labeled alfentanil (alfentanil-d5), 1 mg unlabeled alfentanil was administered over 1 h by an intravenous infusion. Blood samples were collected for 12 h. Concentrations of alfentanil and alfentanil-d5 were measured by a combination of gas chromatography and mass fragmentography. The systemic absorption profiles of alfentanil-d5 were determined by deconvolution of the plasma alfentanil-d5 concentrations with the biexponential unit disposition functions, derived from the intravenous data. In addition, data were analyzed by moment analysis. Results The mean (+/- SD) steady-state volume of distribution, total plasma clearance, elimination half-life and mean residence time, derived from the unlabeled alfentanil concentration-time data, were 43.2 +/- 19.5 1,418 +/- 129 ml/min, 119 +/- 34 min, and 103 +/- 26 min, respectively. The absorption of alfentanil-d5 was monophasic in most patients. The mean systemic availability and mean absorption time derived from the deconvolution data were 100 +/- 17% and 114 +/- 24 min. The values determined by moment analysis were 107 +/- 18% and 112 +/- 36 min, respectively. Conclusions After epidural administration alfentanil is slowly absorbed into the general circulation. Resulting plasma concentrations are very low and do not contribute appreciably to the systemic opioid effect.

Immature pollen grains of Nicotiana tabacum L., cv ‘Petit Havana’ were isolated at the mid-binucleate stage and cultured in vitro. During the first 66 h of in-vitro culture the pollen developed the same ability to set seed and germinate as pollen matured in vivo. No fertile pollen was produced when protein synthesis was inhibited temporarily at an early stage of development. In the case of inhibition at day 2 of development a delay in the total time necessary for maturation was observed that was equal to the length of time the inhibitor was applied. Hybridization experiments with a pollen-specific cDNA probe showed that the pattern of gene expression in vitro was similar to that in vivo. However, the model system differs from natural pollen development with respect to the dehydration period, which is absent in the model system, and the synthesis of proteins. Protein synthesis of in-vitro cultured pollen differed significantly from that of pollen developing in vivo, even though pollen maturation in vitro proceeded in the same time as in vivo, and led to fully matured fertile pollen. Pollen development in vitro is thus an ideal model system for studying gene expression in relation to fertility and for experimental manipulation of microsporogenesis.

We discuss a problem of the formation of neutron stars and black holes from massive stars. It appears that several independent lines of evidence indicate that a considerable fraction of the stars more massive than 20–25 M⊙ leave black holes as remnants, while, on the other hand, the neutron star in at least one high mass x-ray binary had a progenitor more massive than 50 M⊙. We suggest that if the collapsing core has a strong magnetic field and rotates rapidly it will produce a neutron star which expells the remaining matter of the star producing an observable Supernova, whereas if it is not strongly magnetized and/or is slowly rotating it collapses silently to a black hole. This model allows one to understand: (i) the large range in masses of the black holes in the soft x-ray transients (SXT), from about 3 M⊙ to > 12 M⊙ (ii) the fact that in some x-ray binaries of very high mass (> 50 M⊙) one still sometimes finds neutron stars, (iii) the observed fact that the birthrates of SXT with neutron stars and black holes are of the same order of magnitude and (iv) that galactic nucleosynthesis requires no contribution from stars more massive than 20–25 M⊙

Het Universitair Kinderziekenhuis St Radboud verricht zijn onderzoek binnen het onderzoeksraamwerk van het umc St Radboud. Het onderzoek is ondergebracht in gelijkwaardige hoofdprogramma’s en dwarsverbanden. De hoofdprogramma’s worden gevormd door een vijftal thema’s: oncologie; nier- en vaataandoeningen; neurowetenschappen; infectie, ontsteking, trauma en herstel; en genetische en metabole aandoeningen. Deze thema’s worden met elkaar verbonden door een drietal zogenaamde dwarsverbanden: moleculaire levenswetenschappen; translationeel, farmacologisch en klinisch onderzoek; en evaluatie en preventie in de gezondheidszorg.

The role of hormones, especially auxins, during fruit and seed development is well established and the role of gibberellins has been studied previously (Barendse et al.,1991). The work of Jacobsen and Olszewski (1991) associated a special role for gibberellin (GA) in tomato by studying early flower and anther development in the GA deficient gib-1 mutant. The GA effects obtained with this mutant could not be achieved with other plant hormones.

In 1962 the first extrasolar X-ray source, Sco X-1, was discovered (Giacconi et al. 1962) and by the end of the 1960s several dozen such strong point X-ray sources had been discovered with rocket and balloon experiments.

Mismatching between beta-methyl-p-iodophenyl-pentadecanoic acid (BMIPP) and perfusion accurately predicts functional outcome after acute myocardial infarction. The current investigation was aimed at evaluating the value of this method to predict the evolution of global function according to the applied treatment in patients with chronic ischemic heart disease.Twenty patients with infarction and chronic left ventricular dysfunction were studied (median infarction age 12 wk, range 2 wk-15 y). Radionuclide angiography, two-dimensional echocardiography and BMIPP and gated sestamibi scintigraphy were performed with the patient at rest before and6 mo after treatment (revascularization in 13 patients and conservative therapy in 7 patients). In 7 patients, radionuclide angiography was repeated after 1 y.On a patient basis, mismatching with BMIPP less than sestamibi was noted in 15 patients at baseline. Of these 15 patients, 11 had significant functional improvement at follow-up versus only 1 of the 5 patients with a matched decreased uptake. Hence, the combined sestamibi/BMIPP was 73% positive and 80% negative in predicting functional outcome, with a global accuracy of 75%. On a segmental basis, using an optimal threshold of uptake defined by receiver operating characteristic curve analysis, sestamibi was only 63% accurate in predicting regional outcome. Adding BMIPP improved the accuracy to 80% (P = 0.001). At follow-up, significant mismatching was still noted in 7 patients in the revascularized group and 1 in the medically treated group. The mismatch was associated with a further increase in ejection fraction at 1-y follow-up in only the revascularized group.In patients with chronic left ventricular dysfunction after infarction, a mismatching with BMIPP less than sestamibi reliably identifies jeopardized but viable myocardium and predicts functional recovery with an accuracy similar to that reported in the acute and subacute phases of the infarction.

Observation of an eccentric millisecond binary pulsar challenges the standard model of millisecond pulsar formation.

By comparing relative rates of supernovae versus formation rates of single radio pulsars, recycled pulsars, binary pulsars and X-ray binaries we put strong limits on the progenitors of radio pulsars and on the requirement of an asymmetry in the supernova. The assumption that radio pulsars are only formed in type Ib and type Ic supernovae from interacting binaries (Iben & Tutukov 1996) breaks down on the implication that in that case either the formation rate of binary pulsars (double neutron stars) should be of the order of 20%, of the single pulsar birthrate or, alternatively, almost all single pulsars (85% to 98%) should originate from Thorne-Zytkow stars. In the latter case the pulsar velocity distribution is inconsistent with observations. Also, in that case the difference between the supernova rate and the pulsar formation rate would be about one order of magnitude, i.e.: much larger than observed. Allowing type II supernovae from single stars and non-interacting binaries to form radio pulsars solves this conundrum, but then a kick is required in order to explain the high velocities of single radio pulsars. A kick is also required to understand the small birthrate, relative to the supernova rate, of binary pulsars consisting of two neutron stars., 15 pages, New Astronomy in press

SN 2006gy is an extremely luminous super-nova explosion, perhaps a hundred times more energetic than a typical supernova arising from the collapse of the core of a massive star. Current theories suggest that its progenitor was a star more than 100 times the mass of the Sun. That conclusion is at odds with the supernova's spectrum, which indicates the presence of a hydrogen envelope that would have been lost by a massive star long before the explosion. Two groups now present evidence to support alternative explanations for this supernova, both involving collision. Simon Portegies Zwart and Edward van den Heuvel show that the collision frequency of massive stars in a dense young cluster is sufficient to cause an explosion of the scale of SN 2006gy. And Woosley et al. present a model that explains the brightest supernovae as products of collisions between shells of matter ejected by massive stars made unstable by the production of electron–positron pairs. Supernova 2006gy in the galaxy NGC 1260 is the most luminous one recorded. Its progenitor might have been a very massive star, but that is incompatible with hydrogen in the spectrum of the supernova. Instead, it might have arisen from the merger of two massive stars. However, the collision frequency of massive stars in a dense and young cluster is sufficient to provide a reasonable chance that SN 2006gy resulted from such a bombardment. Supernova SN 2006gy in the galaxy NGC 1260 is the most luminous recorded1,2,3,4. Its progenitor might have been a very massive (>100 , where is the mass of the Sun) star5, but that interpretation is incompatible with hydrogen in the spectrum of the supernova; stars >40 are believed to have shed their hydrogen envelopes several hundred thousand years before the explosion6. Alternatively, the progenitor might have arisen from the merger of two massive stars7. Here we show that the collision frequency of massive stars in a dense and young cluster (of the kind to be expected near the centre of a galaxy) is sufficient to provide a reasonable chance that SN 2006gy resulted from such a bombardment. If this is the correct explanation, then we predict that when the supernova fades (in a year or so) a dense cluster of massive stars will become visible at the site of the explosion.

Discordance between 123I-15-(p-iodophenyl)-3-(R,S)-methyl pentadecanoic acid (BMIPP) and sestamibi uptake has been described as a good predictor of functional recovery in patients with a recent myocardial infarction. The current investigation aimed at evaluating BMIPP as a viability tracer in patients with chronic ischemic left ventricular dysfunction.Thirty-one studies were obtained in 25 patients with severe left ventricular dysfunction postinfarction (median infarction age 3.6 mo; range 2 wk-15 yr). All patients underwent dobutamine stress echocardiography and a resting 99mTc-sestamibi/123I-BMIPP SPECT study in a 3-day interval. The relative uptake of the two tracers was compared to the evolution of wall motion during dobutamine infusion in 8 matched myocardial segments.Among the 130 segments with abnormal wall motion at rest, 70 improved under dobutamine. Using sestamibi, a normal uptake was 88% predictive of a positive response to dobutamine, and a decreased uptake of 63% predicted negative stress echocardiography response. In the segments with abnormal sestamibi uptake, adding BMIPP significantly increased the accuracy of scintigraphy to detect residual viability; 28 of 48 segments (58%) with a mismatched pattern demonstrating residual inotropic reserve under dobutamine infusion versus only 5 of 40 segments (13%) with a matched defect. Global agreement between the two approaches was 77%, and positive and negative predictive values for scintigraphy were 72% and 88%, respectively.In patients with chronic ischemic left ventricular dysfunction, the combined assessment of metabolism and perfusion with 123I-BMIPP and 99mTc-sestamibi correlates well with the response of wall motion to dobutamine during stress echocardiography and is more sensitive than sestamibi alone for differentiating viable from scar segments.

Rotating neutron stars, or pulsars, slow down with time. New observations of an unusual intermittent pulsar provide direct evidence that this slowing is partially caused by outflow of plasma.

It is unknown how the programs underlying plant developmental processes manifest themselves in terms of ordered gene expression (1). An important developmental process in plants is pollen grain development (gametogenesis).

Most evidence on X-ray emission from the vicinity of Be stars concerns the Be/X-ray binaries. Presently some 20 of these systems are known, making them the most numerous class of massive X-ray binaries. Evidence for the binary nature of these systems comes from (i) Doppler modulation of X-ray pulse periods, (ii) periodic X-ray flaring behavior, and (iii) correlated optical and X-ray variability. The correlation between X-ray pulse period and orbital period found by Corbet (1984) can potentially provide important information on the densities and velocities in the circumstellar disks of Be stars.Evolutionary models indicate that the Be/X-ray binaries represent a later stage in the evolution of normal close binaries with initial primary masses predominantly in the the range 8 to 15 M⊙ . These models indicate that also a class of slightly less massive Be star binaries should exist in which the compact companions are white dwarfs. Be-type blue stragglers in galactic clusters may be such systems.

The expected final evolution of massive close binaries (CB) in case B is reviewed. Primary stars with masses ≳ 12–15 M⊙ are, after loosing most of their envelope by mass exchange, expected to explode as supernovae, leaving behind a neutron star or a black hole.Conservative close binary evolution (i.e. without a major loss of mass and angular momentum from the system during the first stage of mass transfer) is expected to occur if the initial mass ratio q0 = M20/M10 is ≳ 0.3. In this case the primary star will be the less massive component when it explodes, and the system is almost never disrupted by the explosion. The explosion is followed by a long-lasting quiet stage (106–107 yr) when the system consists of a massive main-sequence star and an inactive compact companion. After the secondary has left the main-sequence and becomes a blue supergiant with a strong stellar wind, the system becomes a massive X-ray binary for a short while (2–5 × 104 yr).The numbers of Wolf-Rayet binaries and massive X-ray binaries observed within 3 kpc of the Sun are in reasonable agreement with the numbers expected on the basis of conservative CB evolution, which implies that several thousands of massive main-sequence stars with a quiet compact companion should exist in the Galaxy. About a dozen of these systems must be present among the stars visible to the naked eye. During the second stage of mass exchange, large loss of mass and angular momentum from the system is expected, leading to a rapid shrinking of the orbit. The supernova explosion of the secondary will in most cases disrupt the system. If it remains bound, the final system will consist of two compact stars and may resemble the binary pulsar PSR 1913 + 16.In systems with q0 ≲ 0.2–0.3 large mass loss from the system is expected during the first stage of mass exchange. The exploding primary will then be more massive than its unevolved companion and the first supernova explosion disrupts the system in most cases. In the rare cases that it remains bound, the system will have a large runaway velocity and, after a very long (108–109 yr) inactive stage evolves into a low-mass X-ray binary, possibly resembling Her X-1.