Single-shot correlations and two-qubit gate of solid-state spins.

Measurement of coupled quantum systems plays a central role in quantum information processing. We have realized independent single-shot read-out of two electron spins in a double quantum dot. The read-out method is all-electrical, cross-talk between the two measurements is negligible, and read-out fidelities are ~86% on average. This allows us to directly probe the anticorrelations between two spins prepared in a singlet state and to demonstrate the operation of the two-qubit exchange gate on a complete set of basis states. The results provide a possible route to the realization and efficient characterization of multiqubit quantum circuits based on single quantum dot spins.

Drosophila melanogaster Thor and response to Candida albicans infection.

We used Drosophila melanogaster macrophage-like Schneider 2 (S2) cells as a model to study cell-mediated innate immunity against infection by the opportunistic fungal pathogen Candida albicans. Transcriptional profiling of S2 cells coincubated with C. albicans cells revealed up-regulation of several genes. One of the most highly up-regulated genes during this interaction is the D. melanogaster translational regulator 4E-BP encoded by the Thor gene. Analysis of Drosophila 4E-BP(null) mutant survival upon infection with C. albicans showed that 4E-BP plays an important role in host defense, suggesting a role for translational control in the D. melanogaster response to C. albicans infection.

Robust quantum communication using a polarization-entangled photon pair.

Noise and imperfection of realistic devices are major obstacles for implementing quantum cryptography. In particular, birefringence in optical fibers leads to decoherence of qubits encoded in photon polarization. We show how to overcome this problem by doing single qubit quantum communication without a shared spatial reference frame and precise timing. Quantum information will be encoded in pairs of photons using tag operations, which corresponds to the time delay of one of the polarization modes. This method is robust against the phase instability of the interferometers despite the use of time bins. Moreover synchronized clocks are not required in the ideal no photon loss case as they are necessary only to label the different encoded qubits.

Double-hairpin elements in the mitochondrial DNA of allomyces: evidence for mobility.

The mitochondrial DNA (mtDNA) of the chytridiomycete fungus Allomyces macrogynus contains 81 G+C-rich sequence elements that are 26-79 bases long and can be folded into a unique secondary structure consisting of two stem-loops. At the primary sequence level, the conservation of these double-hairpin elements (DHEs) is variable, ranging from marginal to complete identity. Forty of these DHEs are inserted in intergenic regions, 35 in introns, and 6 in variable regions of rRNA genes. Ten DHEs are inserted into other DHE elements (twins); two even form triplets. A comparison of DHE sequences shows that loop regions contain more sequence variation than helical regions and that the latter often contain compensatory base changes. This suggests a functional importance of the DHE secondary structure. We further identified nine DHEs in a 4-kb region of Allomyces arbusculus, a close relative of A. macrogynus. Eight of these DHEs are highly similar in sequence (90%-100%) to those in A. macrogynus, but only five are inserted at the same positions as in A. macrogynus. Interestingly, DHEs are also found in the mtDNAs of other chytridiomycetes, as well as certain zygomycete and ascomycete fungi. The overall distribution pattern of DHEs in fungal mtDNAs suggests that they are mobile elements.

The fungal mitochondrial genome project: evolution of fungal mitochondrial genomes and their gene expression.

The goal of the fungal mitochondrial genome project (FMGP) is to sequence complete mitochondrial genomes for a representative sample of the major fungal lineages; to analyze the genome structure, gene content, and conserved sequence elements of these sequences; and to study the evolution of gene expression in fungal mitochondria. By using our new sequence data for evolutionary studies, we were able to construct phylogenetic trees that provide further solid evidence that animals and fungi share a common ancestor to the exclusion of chlorophytes and protists. With a database comprising multiple mitochondrial gene sequences, the level of support for our mitochondrial phylogenies is unprecedented, in comparison to trees inferred with nuclear ribosomal RNA sequences. We also found several new molecular features in the mitochondrial genomes of lower fungi, including: (1) tRNA editing, which is the same type as that found in the mitochondria of the amoeboid protozoan Acanthamoeba castellanii; (2) two novel types of putative mobile DNA elements, one encoding a site-specific endonuclease that confers mobility on the element, and the other constituting a class of highly compact, structured elements; and (3) a large number of introns, which provide insights into intron origins and evolution. Here, we present an overview of these results, and discuss examples of the diversity of structures found in the fungal mitochondrial genome.

Mitochondrial tRNAs in the lower fungus Spizellomyces punctatus: tRNA editing and UAG 'stop' codons recognized as leucine.

The mitochondrial DNA of the chytridiomycete fungus Spizellomyces punctatusen codes only eight tRNAs, although a minimal set of 24-25 tRNAs is normally found in fungi. One of these tRNAs has a CAU anticodon and is structurally related to leucine tRNAs, which would permit the translation of the UAG 'stop' codons that occur in most of its protein genes. The predicted structures of all S. punctatus tRNAs have the common feature of containing one to three mis-pairings in the first three positions of their acceptor stems. Such mis-pairing is expected to impair proper folding and processing of tRNAs from their precursors. Five of these eight RNAs were shown to be edited at the RNA level, in the 5'portion of the molecules. These changes include both pyrimidine to purine and A to G substitutions that restore normal pairing in the acceptor stem. Editing was not found at other positions of the tRNAs, or in the mitochondrial mRNAs of S. punctatus. While tRNA editing has not been observed in other fungi, the editing pattern inS.punctatus is virtually identical to that described in the amoeboid protozoan Acanthamoeba castellanii. If this type of mitochondrial tRNA editing has originated from their common ancestor, one has to assume that it was independently lost in plants, animals and in most fungi. Alternatively, editing might have evolved independently, or the genes coding for the components of the editing machinery were laterally transferred.

Evaluation of a knowledge-based system providing ventilatory management and decision for extubation.

We evaluated whether a knowledge-based system (KBS) connected to a ventilator in pressure support mode could correctly predict the ability of patients to tolerate total withdrawal from ventilatory support. The KBS was designed to continuously adapt ventilatory assistance to the needs of the patient, to manage a strategy of gradually decreasing ventilatory assistance, and to indicate when the patient was able to breathe without assistance. Thirty-eight patients for whom weaning was being considered were evaluated using a conventional battery of parameters, including weaning criteria, tolerance of a T-piece trial, and outcome 48h after permanent withdrawal of ventilation. The results of this evaluation were compared with the suggestions made by the KBS at the end of a period of KBS-driven mechanical ventilation inserted in the conventional weaning procedure. The positive predictive value of the KBS was 89%, versus 77% for the conventional procedure and 81% for the rapid shallow breathing index alone. The KBS correctly predicted the course of five patients who tolerated a T-piece trial but required ventilation within 48 h. We conclude that our KBS ensured appropriate patient management during the weaning period and improved our ability to predict responses to weaning.

Interspecific transfer of mitochondrial genes in fungi and creation of a homologous hybrid gene.

In eukaryotes, horizontal gene transfer is a rare event. Here we show that the mitochondrial genome of a lower fungus, Allomyces macrogynus, has an extra DNA segment not present in a close relative, Allomyces arbusculus. This insert consists of the C terminus of a foreign gene encoding a subunit of the ATP synthetase complex (atp6) plus an open reading frame encoding an endonuclease. The inserted atp6 portion is fused in phase to the resident gene, resulting in expression of a hybrid atp6 gene and the displacement of the original C-terminal atp6 region. We present evidence that this insertion may have been acquired by interspecific transfer and we discuss the possible role of the endonuclease in this process.

Palatability of a meal influences release of beta-endorphin, and of potential regulators of food intake in healthy human subjects.

The effect of the palatability of a meal was tested on the post-prandial release of several gut hormones or neuropeptides which are known to have an effect on intake and satiety. Hormonal response was determined in plasma during the 3 h after a highly palatable and energy-rich meal or after the same meal served cold in a poorly acceptable form, as well as while fasting. The early post-prandial pancreatic polypeptide and neurotensin response was significantly higher after the highly palatable meal than after the cold one. Later responses differed only for pancreatic polypeptide. No difference was observed in cholecystokinin and neuropeptide Y levels. Post-prandial levels of beta-endorphin were elevated only after the cold meal and were associated with an elevated response of ACTH. We suggest that beta-endorphin might be secreted in response to an aversion towards the non-palatable cold meal. This could, subsequently, inhibit the cephalic phase of pancreatic polypeptide response and the early post-prandial response of neurotensin by a central anticholinergic effect. This study evidences an effect of palatability on the modulation of the digestive hormonal response after a meal.

Neuropsychiatric nursing: a useful adjunct to comprehensive neuroscience nursing care.

Neurological illness often influences the patient's behavior either as a direct result of trauma or due to pathophysiological changes to the brain. Neurological patients also experience psychological responses to their illness resulting in a heightened potential for a dual impact on behavior. The neuropsychiatric nurse provides care to patients with severe or unusually persistent behavioral manifestations of illness. Neurologic, psychiatric, cognitive and functional assessments are completed by the neuropsychiatric nurse to obtain an accurate picture of the behavioral problem. Nursing interventions are then developed to improve functional ability and promote independence. If a neuropsychiatric nurse is not available many of these assessment skills can be employed by neuroscience nurses and implemented on neurological and neurosurgical units.

[A laxative jam]. / Une confiture laxative.

A study on the effects of a laxative jam was done on a group of veterans hospitalized at Le Centre hospitalier de l'Université Laval, Sainte-Foy (Québec). The jam, made up of a mixture of dates and prunes, was tried as a form of treatment to see whether it would increase the frequency of bowel movements and decrease laxative use in long-term care elderly patients. Analysis of the treatment group revealed a significant increase in the frequency of bowel movements and a similar decrease in laxative use. No change was observed in the other patients. Although the addition of this jam amounted to a monthly expense of 167$, it has remained part of the diet on a PRN basis.

Lack of plasmic beta-endorphin response to a gastronomic meal in healthy humans.

In order to study the relationship between the endogenous opiate system and food intake in man, plasma concentrations of beta-endorphin were measured in ten healthy subjects. Time course of beta-endorphinemia was compared under the following conditions: basal (fasting), after an injection of pentagastrin (6 micrograms/kg), or after a gastronomic meal. No changes in plasma beta-endorphin or ACTH concentrations were observed with pentagastrin nor after the meal, despite the combination of very high sensory pleasure with intake of a very large amount of food. It is concluded that blood beta-endorphin concentration is not a sensitive index of the effects of food intake on the endogenous opioid system in man.

Pharmacokinetics and biodistribution of technetium 99m labelled standard heparin and a low molecular weight heparin (enoxaparin) after intravenous injection in normal volunteers.

For a better understanding of low molecular weight heparin pharmacokinetics, 99m technetium labelled heparin and enoxaparin were injected intravenously to four normal volunteers, after approval by the Ethics Committee and preliminary animals studies. In vitro and in vivo, the labelled products proved to be stable and identical to the non-labelled drugs. Radioactivity curves in blood, organs and urines were similar for both products. Anti Xa plasma half-life was 3 times longer for enoxaparin than for heparin. Anti IIa plasma half-lives were similar. However, radioactivity persisted much longer than biological activities for both products. After chromatography, most of the radioactivity was bound to AT III, where an anti Xa activity peak was also detected. The anti Xa activity peak seen after adding AT III to plasma was much higher with heparin than with enoxaparin. In urine, biological activities, measured with AT III supplementation, were higher with enoxaparin than with heparin. These results suggest that phenomena other than biodistribution are responsible for the differences in pharmacokinetics observed between these two products. The two most likely explanations are differences in metabolism and/or a release of an endogenous factor.

Pharmacokinetics and tissue distribution of 99mTc-labelled enoxaparin in the rat: evaluation of dosimetry parameters.

A low molecular weight heparin, enoxaparin, was labelled with 99mTc and the characteristics of the labelled compound determined. In vitro the stability, and labelling efficiency (98%) of the labelled drug were excellent. Rats were injected with 99mTc-enoxaparin to study pharmacokinetics and distribution. The results were used to calculate dosimetric estimates which are a prerequisite for pharmacokinetic studies on labelled LMWH (low molecular weight heparin) in human subjects. Biodistribution studies showed preferential liver and spleen accumulation. But the doses absorbed by these target organs remained below the upper limits of the dose received by a patient undergoing hepatic scintigraphy.

Low thyrotropin (TSH) levels in goiter. Relationship with scintigraphic findings and other biological parameters.

Low TSH levels are frequently encountered in patients presenting with goiter. We assayed TSH in 599 goitrous patients who were referred to us for scintigraphy and ultrasonography. When TSH levels were low or when a hot nodule was discovered at scintigraphy, free T3, free T4 and sex hormone-binding globulin (SHBG) were also assayed. TSH levels were always low in overt hyperthyroidism with elevated free T3. TSH levels were also low in patients with normal free T3 and free T4 in circumstances leading to mild hyperthyroidism such as hot nodules that suppressed extranodular thyroid tissue uptake, toxic multinodular goiter, De Quervain thyroiditis and some patients on amiodarone treatment. Low TSH levels were also encountered in 29% of the clinically euthyroid patients presenting with a multinodular goiter with normal iodine uptake, no hot area and normal free T3 levels. In diffuse goiter, low TSH and normal free T3 levels were more frequently associated when iodine uptake was low, mainly due to subacute thyroiditis which can be clinically silent. Low TSH levels were rarely observed in patients with "simple" goiter or uninodular goiter without hot areas. SHBG, which was elevated in 94% of the Graves' disease patients tested, was normal in all but two patients with low TSH and normal free T3 levels. This assay appeared to be of little relevance in goiter. In addition to imaging techniques which are usually performed first, TSH should be systematically assayed in goiter, except in cases of solitary cold nodules. When low, the patient is at risk of developing overt hyperthyroidism. Conversely, when an isolated low TSH level is observed, scintigraphy should be performed.

Predisposing factors in anaphylactoid reactions to anaesthetic drugs in an Australian population: the role of allergy, atopy and previous anaesthesia.

One thousand patients undergoing anaesthesia in an Australian hospital were assessed by questionnaire to determine the incidence of previous anaesthesia, allergy and atopy. The patients were compared with a British group and with 85 patients who had life-threatening anaphylactoid reactions. The Australian and British groups were not significantly different. The Australian patients who had reactions showed a higher incidence of allergy, atopy, asthma and previous adverse reactions than the general population. The incidence was higher in females than males. Although the incidence is higher in the group of patients who reacted, the incidence is not sufficiently great to make pretreatment of patients with a history of allergy or atopy a reasonable prophylactic manoeuvre.