Scale-up of mixer granulators for effective liquid distribution

There is considerable anecdotal evidence from industry that poor wetting and liquid distribution can lead to broad granule size distributions in mixer granulators. Current scale-up scenarios lead to poor liquid distribution and a wider product size distribution. There are two issues to consider when scaling up: the size and nature of the spray zone and the powder flow patterns as a function of granulator scale. Short, nucleation-only experiments in a 25L PMA Fielder mixer using lactose powder with water and HPC solutions demonstrated the existence of different nucleation regimes depending on the spray flux Psi(a)-from drop-controlled nucleation to caking. In the drop-controlled regime at low Psi(a) values. each drop forms a single nucleus and the nuclei distribution is controlled by the spray droplet size distribution. As Psi(a) increases, the distribution broadens rapidly as the droplets overlap and coalesce in the spray zone. The results are in excellent agreement with previous experiments and confirm that for drop-controlled nucleation. Psi(a) should be less than 0.1. Granulator flow studies showed that there are two powder flow regimes-bumping and roping. The powder flow goes through a transition from bumping to roping as impeller speed is increased. The roping regime gives good bed turn over and stable flow patterns. This regime is recommended for good liquid distribution and nucleation. Powder surface velocities as a function of impeller speed were measured using high-speed video equipment and MetaMorph image analysis software, Powder surface velocities were 0.2 to 1 ms(-1)-an order of magnitude lower than the impeller tip speed. Assuming geometrically similar granulators, impeller speed should be set to maintain constant Froude number during scale-up rather than constant tip speed to ensure operation in the roping regime. (C) 2002 Published by Elsevier Science B.V.

Ultrastructure of the mature spermatozoon of the musky rat-kangaroo, Hypsiprymnodon moschatus (Potoroidae : Marsupialia)

It is currently accepted that Hypsiprymnodon moschatus is a basal macropod, retaining several primitive features from the ancestral phalangeroid that gave rise both to modern possums and macropods. Sperm ultrastructure is frequently found to provide informative characters for phylogenetic analysis as these features are not strongly selected for and are thus unlikely to be confounded by effects such as convergence. Caudal epididymal biopsies were taken from two male H. moschatus and prepared for transmission and scanning electron microscopy in order to study mature spermatozoan ultrastructure. Within the diprotodont group, several features were found to be unique to H. moschatus. These were an unusual acrosome covering nearly 100% of the dorsal nuclear surface, a midpiece fibre network which is loose, indistinct and extends to the anterior-most aspect of the midpiece, a nucleus that is very streamlined, while the principal piece is comparatively short, and a mitochondrial helix and annulus which are similar to those of dasyurids. Also reported is the presence of a fibrous network in die connecting piece, not previously reported for any marsupial.

Contribution of cholinergic systems to state-dependent modulation of respiratory control

Respiration is altered during different stages of the sleep-wake cycle. We review the contribution of cholinergic systems to this alteration, with particular reference to the role of muscarinic acetylcholine receptors (MAchRs) during rapid eye movement (REM) sleep. Available evidence demonstrates that MAchRs have potent excitatory effects on medullary respiratory neurones and respiratory motoneurones, and are likely to contribute to changes in central chemosensitive drive to the respiratory control system. These effects are likely to be most prominent during REM sleep, when cholinergic brainstem neurones show peak activity levels. It is possible that MAchR dysfunction is involved in sleep-disordered breathing, Such as obstructive sleep apnea. (C) 2002 Elsevier Science B.V. All rights reserved.

Comparative sperm ultrastructure in five genera of the nudibranch family Chromodorididae (Gastropoda : Opisthobranchia)

Sperm ultrastructure is examined in representatives of five genera of the nudibranch gastropod family Chromodorididae: (Chromodoris, Hypselodoris, Glossodoris, Risbecia and Pectenodoris) and the results compared with previous work on other gastropods, especially other nudibranchs. As chromodoridid phylogeny is still incompletely understood, this study partly focuses on the search for new and as yet untapped sources of informative characters. Like spermatozoa of most other heterobranch gastropods, those of the Chromodorididae are elongate, complex cells composed of an acrosomal complex (small, rounded acrosomal vesicle, and columnar acrosomal pedestal), a condensed nucleus, sub-nuclear ring, a highly modified mid-piece (axoneme + coarse fibres surrounded by a glycogen-containing, helically-coiled mitochondrial derivative) and terminally a glycogen piece (or homologue thereof). The finely striated acrosomal pedestal is a synapomorphy of all genera examined here, but interestingly also occurs in at least one dorid (Rostanga arbutus). Substantial and potentially taxonomically informative differences were also observed between genera in the morphology of the nucleus, the neck region of the mid-piece, and also the terminal glycogen piece. The subnuclear ring is shown for the first time to be a segmented, rather than a continuous structure; similarly, the annular complex is shown to consist of two structures, the annulus proper and the herein-termed annular accessory body.

Comparative sperm ultrastructure of the Baikalian endemic prosobranch gastropods

Mature euspermatozoan ultrastructure is described for seven species of the rissooidean family Baicaliidae (endemic to Lake Baikal, Russia)-Liobaicalia stiedae, Teratobaikalia ciliata, T. macrostoma, Baicalia carinata, Pseudobaikalia pulla, Maackia bythiniopsis, M. variesculpta, and M. herderiana. For comparison with these species and previously investigated Rissooidea, two species of the Lake Baikal endemic genus Benedictia (B. cf. fragilis and B. baicalensis; Hydrobiidae: Benedictiinae of some authors, Benedictiidae of other authors) in addition to Lithoglyphus naticoides (Hydrobiidae: Lithoglyphinae) and Bythinella austriaca (Hydrobiidae: Bythinellinae) were also investigated. Paraspermatozoa were not observed in any of the species examined, supporting the view that these cells are probably absent in the Rissooidea. In general, the euspermatozoa of all species examined resemble those of many other caenogastropods (basally invaginated acrosomal vesicle, mid-piece with 7-13 helical mitochondria, an annulus, glycogen piece with nine peri-axonemal tracts of granules). However, the presence of a completely flattened acrosomal vesicle and a specialized peri-axonemal membranous sheath (a scroll-like arrangement of 4-6 double membranes) at the termination of the mid-piece, clearly indicates a close relationship between the Baicaliidae and other rissooidean families possessing these features (Bithyniidae, Hydrobiidae, Pyrgulidae, and Stenothyridae). Euspermatozoa of Benedictia, Lithoglyphus, Bythinella, and Pyrgula all have a solid nucleus, which exhibits a short, posterior invagination (housing the centriolar complex and proximal portion of the axoneme). Among the Rissooidea, this form of nucleus is known to occur in the Bithyniidae, Hydrobiidae, Truncatellidae, Pyrgulidae, Iravadiidae, Pomatiopsidae, and Stenothyridae. In contrast, the euspermatozoa of the Baicaliidae all have a long, tubular nucleus, housing not only the centriolar derivative, but also a substantial portion of the axoneme. Among the Rissooidea, a tubular nuclear morphology has previously been seen in the Rissoidae, which could support the view, based on anatomical grounds, that the Baicaliidae may have arisen from a different ancestral source than the Hydrobiidae. However, the two styles of nuclear morphology (short, solid versus long, tubular) occur widely within the Caenogastropoda, and sometimes both within a single family, thereby reducing the phylogenetic importance of nuclear differences within the Rissooidea. More significantly, the occurrence of the highly unusual membranous sheath within the mid-piece region in the Baicaliidae appears to tie this family firmly to the Bithyniidae + Hydrobiidae + Stenothyridae + Pyrgulidae assemblage. Eusperm features of Benedictia spp. strongly resemble those of hydrobiids and bithyniids, and neither support recognition of a distinct family Benedictiidae (at best this is a subfamily of Hydrobiidae) nor any close connection with the hydrobiid subfamily Lithoglyphinae.

Systemic administration of interleukin-1 beta activates select populations of central amygdala afferents

The central nucleus of the amygdala (CeA) is activated robustly by an immune challenge such as the systemic administration of the proinflammatory cytokine interleukin-1beta (IL-1beta). Because IL-1beta is not believed to cross the blood-brain barrier in any significant amount, it is likely that IL-1beta elicits CeA cell recruitment by means of activation of afferents to the CeA. However, although many studies have investigated the origins of afferent inputs to the CeA, we do not know which of these also respond to IL-1beta. Therefore, to identify candidate neurons responsible for the recruitment of CeA cells by an immune challenge, we iontophoretically deposited a retrograde tracer, cholera toxin b-subunit (CTb), into the CeA of rats 7 days before systemic delivery of IL-1beta (1 mug/kg, i.a.). By using combined immunohistochemistry, we then quantified the number of Fos-positive CTb cells in six major regions known to innervate the CeA. These included the medial prefrontal cortex, paraventricular thalamus (PVT), ventral tegmental area, parabrachial nucleus (PB), nucleus tractus solitarius, and ventrolateral medulla. Our results show that after deposit of CTb into the CeA, the majority of double-labeled cells were located in the PB and the PVT, suggesting that CeA cell activation by systemic IL-1beta is likely to arise predominantly from cell bodies located in these regions. These findings may have significant implications in determining the central pathways involved in generating acute central responses to a systemic immune challenge. J. Comp. Neurol. 452:288-296, 2002. (C) 2002 Wiley-Liss, Inc.

Opposing roles for medial and central amygdala in the initiation of noradrenergic cell responses to a psychological stressor

Psychological stressors trigger the activation of medullary noradrenergic cells, an effect that has been shown to depend upon yet-to-be-identified structures located higher in the brain. To test whether the amygdala is important in this regard, we examined the effects of amygdala lesions on noradrenergic cell responses to restraint, and also looked at whether any amygdala cells that respond to restraint project directly to the medulla. Ibotenic acid lesions of the medial amygdala completely abolished restraint-induced Fos expression in A1 and A2 noradrenergic cells. In contrast, lesions of the central amygdala actually facilitated noradrenergic cell responses to restraint. Tracer deposits in the dorsomedial (but not ventrolateral) medulla retrogradely labelled many cells in the central nucleus of the amygdala, but none of these cells expressed Fos in response to restraint. These data suggest for the first time that the medial amygdala is critical to the activation of medullary noradrenergic cells by a psychological stressor whereas the central nucleus exerts an opposing, inhibitory influence upon noradrenergic cell recruitment. The initiation of noradrenergic cell responses by the medial amygdala does not involve a direct projection to the medulla. Accordingly, a relay through some other structure, such as the hypothalamic paraventricular nucleus, warrants careful consideration.

The distribution and morphological characteristics of serotonergic cells in the brain of monotremes

The distribution and cellular morphology of serotonergic neurons in the brain of two species of monotremes are described. Three clusters of serotonergic neurons were found: a hypothalamic cluster, a cluster in the rostral brainstem and a cluster in the caudal brainstem. Those in the hypothalamus consisted of two groups, the periventricular hypothalamic organ and the infundibular recess, that were intimately associated with the ependymal wall of the third ventricle. Within the rostral brainstem cluster, three distinct divisions were found: the dorsal raphe nucleus (with four subdivisions), the median raphe nucleus and the cells of the supralemniscal region. The dorsal raphe was within and adjacent to the periaqueductal gray matter, the median raphe was associated with the midline ventral to the dorsal raphe, and the cells of the supralemniscal region were in the tegmentum lateral to the median raphe and ventral to the dorsal raphe. The caudal cluster consisted of three divisions: the raphe obscurus nucleus, the raphe pallidus nucleus and the raphe magnus nucleus. The raphe obscurus nucleus was associated with the dorsal midline at the caudal-most part of the medulla oblongata. The raphe pallidus nucleus was found at the ventral midline of the medulla around the inferior olive. Raphe magnus was associated with the midline of the medulla and was found rostral to both the raphe obscurus and raphe pallidus. The results of our study are compared in an evolutionary context with those reported for other mammals and reptiles. Copyright (C) 2002 S. Karger AG, Basel.

The distribution and morphological characteristics of cholinergic cells in the brain of monotremes as revealed by ChAT immunohistochemistry

The present study employs choline acetyltransferase (ChAT) immunohistochemistry to identify the cholinergic neuronal population in the central nervous system of the monotremes. Two of the three extant species of monotreme were studied: the platypus (Omithorhynchus anatinus) and the short-beaked echidna (Tachyglossus aculeatus). The distribution of cholinergic cells in the brain of these two species was virtually identical. Distinct groups of cholinergic cells were observed in the striatum, basal forebrain, habenula, pontomesencephalon, cranial nerve motor nuclei, and spinal cord. In contrast to other tetrapods studied with this technique, we failed to find evidence for cholinergic cells in the hypothalamus, the parabigeminal nucleus (or nucleus isthmus), or the cerebral cortex. The lack of hypothalamic cholinergic neurons creates a hiatus in the continuous antero-posterior aggregation of cholinergic neurons seen in other tetrapods. This hiatus might be functionally related to the phenomenology of monotreme sleep and to the ontogeny of sleep in mammals, as juvenile placental mammals exhibit a similar combination of sleep elements to that found in adult monotremes. Copyright (C) 2002 S. Karger AG, Basel.

Ultrastructure of the mature spermatozoa of caecilians (Amphibia : Gymnophiona)

The spermatozoa of Gymnophiona show the following autapomorphies: 1) penetration of the distal centriole by the axial fiber; 2) presence of an acrosomal baseplate; 3) presence of an acrosome seat (flattened apical end of nucleus); and 4) absence of juxta-axonemal fibers. The wide separation of the plasma membrane bounding the undulating membrane is here also considered to be apomorphic. Three plesiomorphic spermatozoal characters are recognized that are not seen in other Amphibia but occur in basal amniotes: 1) presence of mitochondria with a delicate array of concentric cristae (concentric cristae of salamander spermatozoa differ in lacking the delicate array); 2) presence of peripheral dense fibers associated with the triplets of the distal centriole; and 3) presence of a simple annulus (a highly modified, elongate annulus is present in salamander sperm). The presence of an endonuclear canal containing a perforatorium is a plesiomorphic feature of caecilian spermatozoa that is shared with urodeles, some basal anurans, sarcopterygian fish, and some amniotes. Spermatozoal synapornorphies are identified for 1) the Uraeotyphlidae and Ichthyophiidae, an 2) the Caeciliidae and Typhlonectidae, suggesting that the members of each pair of families are more closely related to each other than to other caecilians. Although caecilian spermatozoa exhibit the clear amphibian synapomorphy of the unilateral location of the undulating membrane and its axial fiber, they have no apomorphic characters that suggest a closer relationship to either the Urodela or Axiura. J. Morphol. 258:179-192, 2003. (C) 2003 Wiley-Liss, Inc.

Biochemical and molecular studies using human autopsy brain tissue

The use of human brain tissue obtained at autopsy for neurochemical, pharmacological and physiological analyses is reviewed. RNA and protein samples have been found suitable for expression profiling by techniques that include RT-PCR, cDNA microarrays, western blotting, immunohistochemistry and proteomics. The rapid development of molecular biological techniques has increased the impetus for this work to be applied to studies of brain disease. It has been shown that most nucleic acids and proteins are reasonably stable post-mortem. However, their abundance and integrity can exhibit marked intra- and intercase variability, making comparisons between case-groups difficult. Variability can reveal important functional and biochemical information. The correct interpretation of neurochemical data must take into account such factors as age, gender, ethnicity, medicative history, immediate ante-mortem status, agonal state and post-mortem and post-autopsy intervals. Here we consider issues associated with the sampling of DNA, RNA and proteins using human autopsy brain tissue in relation to various ante- and post-mortem factors. We conclude that valid and practical measures of a variety of parameters may be made in human brain tissue, provided that specific factors are controlled.

Gest??o p??blica e pesquisa operacional: avalia????o de desempenho em ag??ncias da Previd??ncia Social

O presente trabalho utiliza a metodologia DEA (Data Envelopment Analysis ), para avaliar a efici??ncia das 22 Ag??ncias da Previd??ncia Social ??? Ger??ncia Executiva Fortaleza (APS-GEXFOR). DEA utiliza programa????o linear cujo n??cleo das estruturas anal??ticas ?? formado a partir do modelo original CCR (Charnes, Cooper, e Rhodes). Aplicada ??s DMU (Decision Making Units), define uma Fronteira de Efici??ncia identificando Unidades Eficientes e Ineficientes. Foi utilizado o modelo DEA-CCR implementado pelo software DEA Solver??. A Previd??ncia Social (INSS) disp??e de indicadores de desempenho. Algumas vari??veis utilizadas no modelo implementado derivam desses indicadores, outras informa????es foram disponibilizadas pelos sistemas de informa????o da institui????o. A avalia????o de efici??ncia DEA das APS-GEXFOR permitiu identificar as melhores pr??ticas, mensurar a participa????o de cada vari??vel envolvida na avalia????o da unidade e projetar as unidades ineficientes na fronteira de efici??ncia, identificando metas a serem atingidas para torn??-las eficientes no conjunto observado.

A reestrutura????o da carreira de especialista em pol??ticas p??blicas e gest??o governamental e seu impacto na reforma administrativa de 1995

As reformas administrativas brasileiras sempre foram uma forma de tentar aprimorar a gest??o p??blica em nosso pa??s, mas ?? verdade tamb??m que in??meras vezes elas foram usadas como plataforma eleitoral ou ret??rica em esbo??os de programas de Governo. Podemos considerar como a primeira dessas reformas a realizada na d??cada de 1930 pelo Governo de Get??lio Vargas que reduziu bastante as pr??ticas patrimonialistas de gerir o Estado. Posteriormente tivemos, sem muito sucesso, a tentativa de reforma implantada atrav??s edi????o do Decreto-Lei 200 de 1967, durante os governos militares. Com a redemocratiza????o, tentou-se uma reforma no Governo Sarney, da qual resultou como pontos positivos a cria????o da Escola Nacional de Administra????o P??blica e a cria????o da Carreira de Especialista em Pol??ticas P??blicas e Gest??o Governamental (EPPGG). No Governo Collor tentou-se fazer nova reforma administrativa, que n??o logrou ??xito. J?? no Governo Fernando Henrique Cardoso, o Ministro Bresser Pereira foi respons??vel, a partir de 1995, por implementar uma nova e grande reforma administrativa no Brasil. Um dos objetivos dessa Reforma era o fortalecimento do N??cleo Estrat??gico do Estado; para realizar essa tarefa, Bresser Pereira optou por fortalecer as carreiras do chamado Ciclo de Gest??o do Estado, nesse processo ela realizou uma grande reestrutura????o da carreira de EPPGG. Essa reestrutura????o trouxe para o N??cleo Estrat??gico do Estado um corpo de servidores bem treinados e sintonizados com as propostas de gest??o previstas na Reforma. Esses profissionais tiveram uma participa????o marcante nas mudan??as ocorridas na gest??o da Administra????o P??blica durante os dois Governos de Fernando Henrique, participando de v??rios projetos e ocupando v??rios Cargos de Dire????o em todos os n??veis na Administra????o P??blica. O trabalho de sucesso desses profissionais continuou nos dois mandatos seguintes do Presidente Lula. Na constru????o dessa pesquisa foram utilizados v??rios estudos, livros, artigos e entrevistas que levaram ?? conclus??o que a reestrutura????o da Carreira de EPPGG foi um instrumento eficaz para que a Reforma Administrativa de 1995 tivesse sucesso no objetivo de fortalecer o N??cleo Estrat??gico do Estado.

Neural reflex regulation of arterial pressure in pathophysiological conditions : interplay among the baroreflex, the cardiopulmonary reflexes and the chemoreflex

The maintenance of arterial pressure at levels adequate to perfuse the tissues is a basic requirement for the constancy of the internal environment and survival. The objective of the present review was to provide information about the basic reflex mechanisms that are responsible for the moment-to-moment regulation of the cardiovascular system. We demonstrate that this control is largely provided by the action of arterial and non-arterial reflexes that detect and correct changes in arterial pressure (baroreflex), blood volume or chemical composition (mechano- and chemosensitive cardiopulmonary reflexes), and changes in blood-gas composition (chemoreceptor reflex). The importance of the integration of these cardiovascular reflexes is well understood and it is clear that processing mainly occurs in the nucleus tractus solitarii, although the mechanism is poorly understood. There are several indications that the interactions of baroreflex, chemoreflex and Bezold-Jarisch reflex inputs, and the central nervous system control the activity of autonomic preganglionic neurons through parallel afferent and efferent pathways to achieve cardiovascular homeostasis. It is surprising that so little appears in the literature about the integration of these neural reflexes in cardiovascular function. Thus, our purpose was to review the interplay between peripheral neural reflex mechanisms of arterial blood pressure and blood volume regulation in physiological and pathophysiological states. Special emphasis is placed on the experimental model of arterial hypertension induced by N-nitro-L-arginine methyl ester (L-NAME) in which the interplay of these three reflexes is demonstrable.