Magnetic field effects on the conductivity of organic bipolar and unipolar devices at room temperature

Magnetic field effects on the conductivity of different types of organic devices: undoped and dye doped aluminium (III) 8-hydroxyquinoline (Alq(3))-based organic light emitting diodes (OLEDs), electron-only Alq(3)-based diodes, and a hole-only N,N`-diphenyl-N,N`-bis(1-naphthyl)1,1`-biphenyl-4,4`-diamine (alpha-NPD)-based diode were studied at room temperature. Only negative magnetoresistance (MR) was observed for the Alq(3)-based devices. The addition of a rubrene dye in Alq(3)-based OLEDs quenches the MR by a factor of 5. The alpha-NPD hole-only device showed only positive MR. Our results are discussed with respect to the actual models for MR in organic semiconductors. Our results are in good agreement with the bipolaron model. (C) 2009 Elsevier B.V. All rights reserved.

The Tausk controversy on the foundations of quantum mechanics: Physics, philosophy, and politics

In 1966 the Brazilian physicist Klaus Tausk (b. 1927) circulated a preprint from the International Centre for Theoretical Physics in Trieste, Italy, criticizing Adriana Daneri, Angelo Loinger, and Giovanni Maria Prosperi`s theory of 1962 on the measurement problem in quantum mechanics. A heated controversy ensued between two opposing camps within the orthodox interpretation of quantum theory, represented by Leon Rosenfeld and Eugene P. Wigner. The controversy went well beyond the strictly scientific issues, however, reflecting philosophical and political commitments within the context of the Cold War, the relationship between science in developed and Third World countries, the importance of social skills, and personal idiosyncrasies.

Listening to the Whispers of Matter Through Arabic Hermeticism: New Studies on the Book of the Treasure of Alexander

The Jabirian Corpus refers to the K. Thahirat Al-`Iskandar, ""The Book of the Treasure of Alexander"" (hereafter BTA), as one of several forgeries suggesting that alchemical secrets were hidden in inscriptions in various places. The book was neglected until 1926, when Julius Ruska discussed it in his work on the Emerald Tablet, placing the BTA within the literature related to the development of Arabic alchemy. His preliminary study became an essential reference and encouraged many scholars to work on the BTA in the following decades. Some years ago, we completed the first translation of the BTA into a Western language. The work was based on the acephalous Escorial manuscript, which we identified as a fourteenth-century copy of the BTA. This manuscript is peculiar, as part of it is encoded. After finishing our translation, we started to establish the text of the BTA. At present, the text is in process of fixation-to be followed by textual criticism-and has been the main focus of a thorough study of ours on medieval hermeticism and alchemy. A sample of the work currently in progress is presented in this paper: an analysis of the variations between different manuscripts along with a study and English translation of its alchemical chapter.

Distribution of an asymmetrical copepod, Hatschekia plectropomi, on the gills of Plectropomus leopardus

Hatschekia plectropomi, an ectoparasitic copepod found on the gills, infected Plectropomus leopardus from Heron Island Reef with 100% prevalence (n = 32) and a mean +/- S.E. infection intensity of 131.9 +/- 22.1. The distribution of 4222 adult female parasites across 32 individual host fish was investigated at several organizational levels ranging from the level of holobranch pairs to that of individual filaments. Parasites demonstrated a site preference for the two central holobranchs (2 and 3). Along the lengths of hemibranchs, filaments near the dorsal and ventral ends and those in the proximity of the bend region were rarely occupied. The probability of coming into contact with a suitable attachment site and the ability to withstand ventilation forces at that site were proposed as the major factors affecting distribution. Two H. plectropomi morphotypes were identified based on the direction of body curvature. Regardless of morphotype, 99.9% of individuals were attached such that the convex side of the body was oriented towards the oncoming ventilating water currents. Further, 93.3% of individuals attached to the posterior faces of filaments, leading to a predictable pattern of attachment for this species. It is suggested that the direction of body curvature develops in response to the direction of the ventilating water currents. (c) 2006 The Fisheries Society of the British Isles.

Effect of hypothalamo-pituitary disconnection on the development of anterior pituitary cells in late gestation ovine fetuses

The specific role of the hypothalamus in regulating the developmental profile of anterior pituitary (AP) cells remains largely unknown. The present study evaluated hypothalamic contributions to AP cell development, utilizing the technique of hypothalamo-pituitary disconnection (HPD). HPD of fetal sheep or sham surgery was performed at 110 days gestation (d) (n=6 each group; term ~ 147d). Fetuses were removed and pituitaries collected at 110d (no surgery; n=6) or 141d (sham and HPD groups). The impact of HPD on AP cell development was assessed by single-labeled immunofluorescence for five hormones to identify proportions of AP cells expressing each hormone. HPD was associated with a 70% increase (P

Morphometric Study on the Anatomy of the Fetal Cricoid Cartilage and Comparison Between Its Inner Diameter and Endotracheal Tube Sizes

Objectives: The high incidence of respiratory disorders is one of the main problems in perinatal medical care. With the increased use of intubation, the incidence of laryngeal injury causing stenosis has also increased. The principal constriction point in the infant`s larynx is the midcricoid area. We sought to provide detailed morphometric data on the anatomy of the cricoid cartilage and its relationship with growth and body characteristics of fetuses at 5 to 9 months of gestational age. Methods: Nineteen larynges obtained from 17 stillborn infants and 2 newborn infants ranging in gestational age from 5 to 9 months were studied. Measurements of the cricoid cartilage were made with a millimeter-graded caliper. Results: Weight was the variable most correlated with cricoid measurements. The cricoid lumen configuration showed an almost elliptic shape and did not change with gestational age. The mean inner subglottic cricoid area was 19.27 +/- 9.62 mm(2) and was related to weight and body surface area. Cricoid growth was more pronounced at the outer portion of the cartilage. Conclusions: The cricoid lumen configuration was elliptic, and its mean area was smaller than that of available endotracheal tubes. This lumen area was most influenced by weight and height.

Effects of Time on Ultrastructural Integrity of Parathyroid Tissue Before Cryopreservation

Cryopreservation of parathyroid tissue is used in the surgical treatment of secondary hyperparathyroidism. After surgical resection, the tissue is temporarily maintained in a cell culture solution until it arrives at the specialized laboratory where the cryopreservation process will take place. The present study evaluates the time that the human hyperplastic parathyroid gland tissue can wait before cryopreservation, based on parathyroid cell ultrastructural integrity. This prospective study included 11 patients who underwent total parathyroidectomy with heterotopic autotransplantation and cryopreservation of parathyroid tissue fragments. Part of the tissue was kept in cell culture solution at 4A degrees C. Five time periods between 2 and 24 h were defined, and parathyroid fragments were kept in the solution for that length of time. At the end of each period, the fragments were removed from the transport solution, fixed, and prepared for ultrathin sections. Of the 11 cases studied, 10 showed ultrastructural findings consistent with cellular viability in tissue fragments that remained in the transport solution up to 12 h. Electron microscopy revealed that cell adhesion and the integrity of plasma membranes, nuclei, and mitochondria were preserved in one case for up to 24 h. Changes in mitochondrial structure represented the most constant ultrastructural damage seen in the cases studied, in addition to the presence of edema and cell vacuoles. Analysis of the ultrastructure of hyperplastic parathyroid gland tissue showed that ultrastructural integrity was in most cases properly maintained in fragments stored up to 12 h in a cell culture solution at 4A degrees C.

Mathematical constraints on a theory of human memory - Response

Colonius suggests that, in using standard set theory as the language in which to express our computational-level theory of human memory, we would need to violate the axiom of foundation in order to express meaningful memory bindings in which a context is identical to an item in the list. We circumvent Colonius's objection by allowing that a list item may serve as a label for a context without being identical to that context. This debate serves to highlight the value of specifying memory operations in set theoretic notation, as it would have been difficult if not impossible to formulate such an objection at the algorithmic level.

Impact of allogeneic 2-RBC apheresis on iron stores of Brazilian blood donors

One limiting factor for automated two-red blood cells collections (2-RBC) is its potential iron depletion. We analyzed hematological parameters and iron balance before, two and four months after 2-RBC of 96 non-supplemented male donors. Four months after 2-RBC, ferritin level was significantly lower (P < 0.01) than baseline levels and the number of donors who presented ferritin <30 ng/ml increased from 18 to 47. We concluded that four months was not sufficient for iron recuperation in the population studied. In an attempt to avoid iron depletion after 2-RBC, we recommend augmentation in the interval between blood donations and pre-donation ferritin measurement. (C) 2009 Published by Elsevier Ltd.

The possible role of physical exercise on the treatment of idiopathic inflammatory myopathies

Idiopathic inflammatory myopathies (IIM) are a heterogeneous group of diseases that share some symptoms such as muscular weakness and inflammation of skeletal muscle. Complete recovery of muscle function with pharmacological treatment does not always occur, suggesting that physical inability is a great concern for these patients. In this context, it has been speculated that physical exercise could result in functional benefits to patients with IIM, leading to an improvement in quality of life. In fact, recent studies of polymyositis (PM) and dermatomyositis (DM) support the notion that exercise training improves or at least stabilizes muscle strength and functional ability without inducing disease flares. Importantly, these benefits were observed not only during the chronic phase, but also in the course of active disease. This positive effect was found to be long term, as demonstrated by a six-month significant improvement in exercise capacity and strength. Together, these findings indicate that a well controlled exercise program can be recommended for patients with DM and PM. The optimal exercise modality training and the underlying mechanism for this encouraging response remain to be determined in future studies. (C) 2008 Elsevier B.V. All rights reserved.

On the construction of integrable closed chains with quantum supersymmetry

We present a general prescription for the construction of integrable one-dimensional systems with closed boundary conditions and quantum supersymmetry.

Sheina orri (Myodocopa: Cypridinidae), an ostracod parasitic on the gills of the epaulette shark, Hemiscyllium ocellatum (Elasmobranchii: Hemiscyllidae)

The cypridinid ostracod, Sheina orri, was found on the gills of healthy epaulette sharks, Hemiscyllium, ocellatum, collected from the Great Barrier Reef, Australia, Seventeen of the 28 fish examined had ostracods attached to their gills. Detailed investigation of the gills and ostracods using light microscopy and scanning electron microscopy revealed that ostracods anchor themselves to the gill tissues using their mandibular and maxillular claws. These claws appear to be adapted for this purpose and the process of attachment causes some damage to the host tissues. The observation that ostracods were often located in distinct pockets, formed by local distortion of shark respiratory lamellae, strongly suggests that they had been attached to the gills for considerable time. (C) 1997 Australian Society for Parasitology.