Rapid increases in cytokinin concentration in lateral buds of chickpea (Cicer arietinum L) during release of apical dominance

We examined the role of cytokinins (CKs) in release of apical dominance in lateral buds of chickpea (Cicer arietinum L.). Shoot decapitation or application of CKs (benzyladenine, zeatin or dihydrozeatin) stimulated rapid bud growth. Time-lapse video recording revealed growth initiation within 2 h of application of 200 pmol benzyladenine or within 3 h of decapitation. Endogenous CK content in buds changed little in the first 2 h after shoot decapitation, but significantly increased by 6 h, somewhat later than the initiation of bud growth. The main elevated CK was zeatin riboside, whose content per bud increased 7-fold by 6 h and 25-fold by 24 h. Lesser changes were found in amounts of zeatin and isopentenyl adenine CKs. We have yet to distinguish whether these CKs are imported from the roots via the xylem stream or are synthesised in situ in the buds, but CKs may be part of an endogenous signal involved in lateral bud growth stimulation following shoot decapitation. To our knowledge, this is the first detailed report of CK levels in buds themselves during release of apical dominance.

Candida colonisation as a source for candidaemia

Candida spp. are important healthcare-associated pathogens. Identifying the source of infection is important for prevention and control strategies. The objective of this study was to evaluate candida colonisation sites as potential sources for candidaemia. Sixty-three consecutive patients with a positive blood culture for candida were included. Surveillance cultures were collected from urine, rectum, oropharynx, skin, intravascular catheter tip and skin around catheter. Molecular typing was performed when the same species of candida was isolated from blood and surveillance sites of a patient. C. albicans was associated with 42% of candidaemias, C. parapsilosis 33%, C. tropicalis 16% and C. guilliermondii, C. krusei, C. glabrata, C. holmii and C. metapsilosis were all 2% each. Six of 10 C. parapsilosis catheter tip isolates were indistinguishable from corresponding blood isolates (all in neonates). C. albicans isolates from blood were indistinguishable from corresponding gastrointestinal, tract isolates in 13 of 26 patients and from catheter tip isolates in two patients. In conclusion, the results suggest that gastrointestinal colonisation is the probable source of C. albicans candidaemia and C. parapsilosis is exogenous. (C) 2009 The Hospital, Infection Society. Published by Elsevier Ltd. All rights reserved.

Seven-year trend analysis of nosocomial candidemia and antifungal (fluconazole and caspofungin) use in Intensive Care Units at a Brazilian University Hospital

Candidemia is associated with high morbidity and mortality resulting in significant increases in the length of patients` hospitalization and in healthcare costs. Critically ill patients are at particular risk for candidemia because of their debilitated condition and frequent need for invasive procedures. The aim of this study was to characterize the incidence and epidemiology of candidemia over a seven-year period in intensive care units (ICUs) and the use of fluconazole and caspofungin in a large university-affiliated hospital. All cases of candidemia were identified by surveillance, using the Centers for Diseases Control and Prevention criteria. Demographic variables, use of antifungal (fluconazole and caspofungin) and patient outcomes were evaluated. The 2 test for linear trend was employed to evaluate the distribution of Candida spp. and the use of fluconazole and caspofungin by defined daily dose (DDD) per 1,000 patients-days during the study period. One hundred and eight episodes of candidemia were identified. The overall incidence of candidemia (P=0.20) and incidence of non-Candida albicans Candida infections (P=0.32) remained stable over the study period and ranged from 0.3-0.9 episodes per 1,000 catheter-days and 0.39-0.83 episodes per 1,000 patients-days. However, the use of fluconazole and caspofungin increased significantly (P0.001). While there were no reports of the use of fluconazole for prophylaxis in 1999, its use for this purpose increased from 3% in 2000 to 7.0% (P=0.07) in 2006. C. albicans was the most frequent specie isolated and burns and cancer were the most frequent underlying conditions. The overall mortality was 76%. There was no difference between C. albicans and non-C. albicans Candida infections when the crude and 14-day mortality rates were compared. Our data demonstrated that C. albicans is still the most frequent species causing candidemia in our intensive care units. Our rates of candidemia are lower than those reported from the region and similar to American and European hospitals. Although the incidence of blood stream infections (BSI) and candidemia remained stable, the use of fluconazole and caspofungin increased significantly over the years included in this study but had no impact on the incidence of infections caused by non-C. albicans Candida species.

Impact of antimicrobial resistance on the treatment and outcome of patients with sepsis

Antimicrobial therapy is one of the main stones of sepsis therapy. A recent study of septic shock patients showed that each hour of delay in antimicrobial administration during the ensuing 6 h after the onset of hypotension was associated with a decrease in survival rates. However, many questions regarding the impact of infection caused by antimicrobial-resistant pathogens on the mortality of patients with sepsis still need to be clarified. There is a lack of fair studies in the literature. Most studies have had inadequate sample size, inadequate adjustment for predictors of adverse outcomes, and inadequate definition of appropriate antibiotic therapy. Despite the fact that appropriate therapy is essential to treat sepsis, it seems that severity of underlying diseases and comorbidities are more important than resistance, although the studies were not well designed to examine the real impact of resistance on outcome. Finally, new technologies such as microarray that can identify different microorganisms, genes of resistance, and virulence in a few hours might have a great impact on the treatment of sepsis due to antimicrobial-resistant pathogens in the future.

Biofilms, Infection, and Parenteral Nutrition Therapy

Parenteral nutrition therapy is used in patients with a contraindication to the use of the gastrointestinal tract, and infection is one of its Frequent and severe complications. The objective of the present study was to detect the presence of biofilms and microorganisms adhering to the central venous. catheters used for parenteral nutrition therapy by scanning electron microscopy. Thirty-nine central venous catheters belonging to patients with clinical signs of infection (G I) and asymptomatic patients (G2) and patients receiving central venous catheters for clinical monitoring (G3) were analyzed by semi-quantitative culture and scanning electron microscopy. The central venous catheters of G1 presented more positive cultures than those of G2 and G3 (81% vs 50% and 0%, respectively). However, biofilms were observed in all catheters used and 55% of them showed structures that suggested central venous catheters colonization by microorganisms. Approximately 53% of the catheter infections evolved with systemic infection confirmed by blood Culture. The authors conclude that the presence of a biofilm is frequent and is all indicator of predisposition to infection, which may even occur in patients who are still asymptomatic. (JPEN J Parenter Enteral Nutr. 2009;33:397-403)

Influence of Blood Contamination on Bond Strength of a Self-etching Adhesive to Dental Tissues

Purpose: The aim of this study was to detect the influence of (1) storage period of heparinized blood, (2) type of blood and presence of contaminant, (3) application mode of cleansing agents, and (4) efficacy of cleansing agents on contaminated enamel and dentin during the adhesion process of a one-step adhesive system. Materials and Methods: One hundred four human molars were sectioned into halves along the long axis for enamel and dentin tests. Heparinized and fresh blood were obtained from the same donor, applied and dried to maintain a layer of dry blood on the top of samples. The cleansing agents used were hydrogen peroxide, anionic detergent, and antiseptic solution. A one-step adhesive system (Clearfil S3 Bond) was applied on the dental surface, and composite resin cylinders were built up using Tygon tubing molds. After 24 h, the mu SBS test (1 mm/min) and fracture analysis were performed. Results: There was no statistically significant difference in bond strength values regarding the storage period of heparinized blood and the types of blood. Groups without contamination presented higher bond strengths than contaminated groups. The application mode of the cleansing agents had no influence on bond strength results. There was no statistically significant difference among cleansing agents and they were as effective as a water stream in counteracting the effect of blood contamination. Conclusion: Heparinized blood can be used as a contaminant for up to one week, and it is a reliable procedure to standardize the contaminant. The cleansing agents can be used without friction. A water stream is sufficient to remove blood contamination from dental tissues, before the application of a one-step adhesive system.

Moderately strong vorticity in a bathtub-type flow

Theoretical and numerical analysis is performed for an inviscid axisymmetric vortical bathtub-type flow. The level of vorticity is kept high so that the image of the flow on the radial-axial plane (r-z plane) is not potential. The most significant findings are: (1) the region of validity of the strong vortex approximation is separated from the drain by a buffer region, (2) the power-law asymptote of the stream function, specified by Delta Psi similar to r(4/3) Deltaz, appears near the axis when vorticity in the flow is sufficiently strong and (3) the local Rossby number in the region of the 4/3 power-law the initial vorticity level in the flow and the global Rossby number.

Living with under-fives: a programme for parents with a mental illness

Parenthood is considered a major life role. Yet for people with a major mental illness, it is one that is fraught with difficulties and for which they receive the least support. Research on parenting and parenting programmes for people with a major mental illness is sparse and most of the papers presented do not provide a working model that can be easily replicated. This lack of support for parents or knowledge of working parenting programmes has often resulted in children being placed in care. Occupational therapists working in an Australian mental health service developed a two-stream programme which aimed to consolidate the parent/child relationship and enable the parents to develop effective parenting skills. This programme has a parents' educational stream and a stream with developmentally appropriate activities for the children. Observed outcomes have included the parents becoming more responsive to their children, increased treatment compliance, improved community access, and a decrease in the number of children in temporary foster care.

Monocular and binocular distance cues: insights from visual form agnosia I (of III)

The human nervous system constructs a Euclidean representation of near (personal) space by combining multiple sources of information (cues). We investigated the cues used for the representation of personal space in a patient with visual form agnosia (DF). Our results indicated that DF relies predominantly on binocular vergence information when determining the distance of a target despite the presence of other (retinal) cues. Notably, DF was able to construct an Euclidean representation of personal space from vergence alone. This finding supports previous assertions that vergence provides the nervous system with veridical information for the construction of personal space. The results from the current study, together with those of others, suggest that: (i) the ventral stream is responsible for extracting depth and distance information from monocular retinal cues (i.e. from shading, texture, perspective) and (ii) the dorsal stream has access to binocular information (from horizontal image disparities and vergence). These results also indicate that DF was not able to use size information to gauge target distance, suggesting that intact temporal cortex is necessary for learned size to influence distance processing. Our findings further suggest that in neurologically intact humans, object information extracted in the ventral pathway is combined with the products of dorsal stream processing for guiding prehension. Finally, we studied the size-distance paradox in visual form agnosia in order to explore the cognitive use of size information. The results of this experiment were consistent with a previous suggestion that the paradox is a cognitive phenomenon.

An inverse design of an open, head/neck RF coil for MRI

Radio-frequency (RF) coils are a necessary component of magnetic resonance imaging (MRI) systems. When used in transmit operation, they act to generate a homogeneous RF magnetic field within a volume of interest and when in receive operation, they act to receive the nuclear magnetic resonance signal from the RF-excited specimen. This paper outlines a procedure for the design of open RF coils using the time-harmonic inverse method. This method entails the calculation of an ideal current density on a multipaned planar surface that would generate a specified magnetic field within the volume of interest. Because of the averaging effect of the regularization technique in the matrix solution, the specified magnetic field is shaped within an iterative procedure until the generated magnetic field matches the desired magnetic field. The stream-function technique is used to ascertain conductor positions and a method of moments package is then used to finalize the design. An open head/neck coil was designed to operate in a clinical 2T MRI system and the presented results prove the efficacy of this design methodology.

Shear stress and sediment transport calculations for swash zone modelling

It is shown that the observed difference in sediment transporting efficiency by the swash uprush, compared with the downrush, could be mainly due to greater bed shear stress for a given velocity in the more abruptly accelerated uprush. The bed shear stress generated by an arbitrary free stream velocity time series is modelled in terms of usual wave boundary layer models plus a phase lead (phi(tau) of the bed shear stress compared with the free stream velocity at the peak frequency. With this approach, the total transport amounts in uprush and downrush can be modelled satisfactorily with the same sediment transport formula, without the need for different uprush and downrush coefficients. While the adaptation of sediment transport formulae from steady flow can thus lead to the right total amounts of sediment moved by this method, the timing of the instantaneous sediment transport rates are probably not accurately modelled due to the highly unsteady nature of the swash and the presence of pre-suspended sediment in the uprush. Nevertheless, the proposed method is a useful intermediate step before we have a complete understanding of sediment transport under very rapid accelerations and of the relative contribution of pre-suspended sediment to the onshore sediment transport in swash zones. (C) 2002 Published by Elsevier Science B.V.

Shear stress and sediment transport calculations for sheet flow under waves

A simple method is provided for calculating transport rates of not too fine (d(50) greater than or equal to 0.20 mm) sand under sheet flow conditions. The method consists of a Meyer-Peter-type transport formula operating on a time-varying Shields parameter, which accounts for both acceleration-asymmetry and boundary layer streaming. While velocity moment formulae, e.g.., = Constant x calibrated against U-tube measurements, fail spectacularly under some real waves (Ribberink, J.S., Dohmen-Janssen, C.M., Hanes, D.M., McLean, S.R., Vincent, C., 2000. Near-bed sand transport mechanisms under waves. Proc. 27th Int. Conf. Coastal Engineering, Sydney, ASCE, New York, pp. 3263-3276, Fig. 12), the new method predicts the real wave observations equally well. The reason that the velocity moment formulae fail under these waves is partly the presence of boundary layer streaming and partly the saw-tooth asymmetry, i.e., the front of the waves being steeper than the back. Waves with saw-tooth asymmetry may generate a net landward sediment transport even if = 0, because of the more abrupt acceleration under the steep front. More abrupt accelerations are associated with thinner boundary layers and greater pressure gradients for a given velocity magnitude. The two real wave effects are incorporated in a model of the form Q(s)(t) = Q(s)[theta(t)] rather than Q(S)(t) = Q(S)[u(infinity)(t)], i.e., by expressing the transport rate in terms of an instantaneous Shields parameter rather than in terms of the free stream velocity, and accounting for both streaming and accelerations in the 0(t) calculations. The instantaneous friction velocities u(*)(t) and subsequently theta(t) are calculated as follows. Firstly, a linear filter incorporating the grain roughness friction factor f(2.5) and a phase angle phi(tau) is applied to u(infinity)(t). This delivers u(*)(t) which is used to calculate an instantaneous grain roughness Shields parameter theta(2.5)(t). Secondly, a constant bed shear stress is added which corresponds to the streaming related bed shear stress -rho ($) over bar((u) over tilde(w) over tilde)(infinity) . The method can be applied to any u(infinity)(t) time series, but further experimental validation is recommended before application to conditions that differ strongly from the ones considered below. The method is not recommended for rippled beds or for sheet flow with typical prototype wave periods and d(50) < 0.20 turn. In such scenarios, time lags related to vertical sediment movement become important, and these are not considered by the present model. (C) 2002 Elsevier Science B.V. All rights reserved.

Vertical fluxes of sediment in oscillatory sheet flow

Time series of vertical sediment fluxes are derived from concentration time series in sheet flow under waves. While the concentrations C(z,t) vary very little with time for \z\ < 10d(50), the measured vertical sediment fluxes Q(zs)(z,t) vary strongly with time in this vertical band and their time variation follows, to some extent, the variation of the grain roughness Shields parameter 02,5(t). Thus, sediment distribution models based on the pickup function boundary condition are in some qualitative agreement with the measurements. However, the pickup function models are only able to model the upward bursts of sediment during the accelerating phases of the flow. They are, so far, unable to model the following strong downward sediment fluxes, which are observed during the periods of flow deceleration. Classical pickup functions, which essentially depend on the Shields parameter, are also incapable of modelling the secondary entrainment fluxes, which sometimes occur at free stream velocity reversal. The measured vertical fluxes indicate that the effective sediment settling velocity in the high [(0.3 < C(z,t) < 0.4] concentration area is typically only a few percent of the clear water settling velocity, while the measurements of Richardson and Jeronimo [Chem. Eng. Sci. 34 (1979) 1419], from a different physical setting, lead to estimates of the order 20%. The data does not support gradient diffusion as a model for sediment entrainment from the bed. That is, detailed modelling of the observed near-bed fluxes would require diffusivities that go negative during periods of flow deceleration. An observed general trend for concentration variability to increase with elevation close to the bed is also irreconcilable with diffusion models driven by a bottom boundary condition. (C) 2002 Published by Elsevier Science B.V.

Work domain analysis and sensors II: Pasteurizer II case study

In this paper we use sensor-annotated abstraction hierarchies (Reising & Sanderson, 1996, 2002a,b) to show that unless appropriately instrumented, configural displays designed according to the principles of ecological interface design (EID) might be vulnerable to misinterpretation when sensors become unreliable or are unavailable. Building on foundations established in Reising and Sanderson (2002a) we use a pasteurization process control example to show how sensor-annotated AHs help the analyst determine the impact of different instrumentation engineering policies on a configural display that is part of an ecological interface. Our analyses suggest that configural displays showing higher-order properties of a system are especially vulnerable under some conservative instrumentation configurations. However, sensor-annotated AHs can be used to indicate where corrective instrumentation might be placed. We argue that if EID is to be effectively employed in the design of displays for complex systems, then the information needs of the human operator need to be considered while instrumentation requirements are being formulated. Rasmussen's abstraction hierarchy-and particularly its extension to the analysis of information captured by sensors and derived from sensors-may therefore be a useful adjunct to up-stream instrumentation design. (C) 2002 Elsevier Science Ltd. All rights reserved.

Color constancy and the functional significance of McCollough effects

A central problem in visual perception concerns how humans perceive stable and uniform object colors despite variable lighting conditions (i.e. color constancy). One solution is to 'discount' variations in lighting across object surfaces by encoding color contrasts, and utilize this information to 'fill in' properties of the entire object surface. Implicit in this solution is the caveat that the color contrasts defining object boundaries must be distinguished from the spurious color fringes that occur naturally along luminance-defined edges in the retinal image (i.e. optical chromatic aberration). In the present paper, we propose that the neural machinery underlying color constancy is complemented by an 'error-correction' procedure which compensates for chromatic aberration, and suggest that error-correction may be linked functionally to the experimentally induced illusory colored aftereffects known as McCollough effects (MEs). To test these proposals, we develop a neural network model which incorporates many of the receptive-field (RF) profiles of neurons in primate color vision. The model is composed of two parallel processing streams which encode complementary sets of stimulus features: one stream encodes color contrasts to facilitate filling-in and color constancy; the other stream selectively encodes (spurious) color fringes at luminance boundaries, and learns to inhibit the filling-in of these colors within the first stream. Computer simulations of the model illustrate how complementary color-spatial interactions between error-correction and filling-in operations (a) facilitate color constancy, (b) reveal functional links between color constancy and the ME, and (c) reconcile previously reported anomalies in the local (edge) and global (spreading) properties of the ME. We discuss the broader implications of these findings by considering the complementary functional roles performed by RFs mediating color-spatial interactions in the primate visual system. (C) 2002 Elsevier Science Ltd. All rights reserved.