坦德鲁姆步行桥 澳大利亚墨尔本

正连接比拉容马尔公园(Birrarung Marr)和墨尔本公园体育区的新坦德鲁姆人行天桥,为墨尔本公园建造了一个新的主要到达途径。澳大利亚网球公开赛期间,这座桥是一个主要行人入口。一条经过比拉容马尔公园坡道通向大桥,坡道的布置与已建桥梁和公园景观地形相得益彰。在我们的设计中,我们把"演讲角"的历史景观同横跨"蝙蝠侠大道"的墨尔本公园的网球场连接起     

In-Silico Identified New Natural Sortase A Inhibitors Disrupt S. aureus Biofilm Formation

Sortase A (SrtA) is a membrane-associated enzyme that anchors surface-exposed proteins to the cell wall envelope of Gram-positive bacteria such as Staphylococcus aureus. As SrtA is essential for Gram-positive bacterial pathogenesis but dispensable for microbial growth or viability, SrtA is considered a favorable target for the enhancement of novel anti-infective drugs that aim to interfere with key bacterial virulence mechanisms, such as biofilm formation, without developing drug resistance. Here, we used virtual screening to search an in-house natural compound library and identified two natural compounds, N1287 (Skyrin) and N2576 ((4,5-dichloro-1H-pyrrol-2-yl)-[2,4-dihydroxy-3-(4-methyl-pentyl)-phenyl]-methanone) that inhibited the enzymatic activity of SrtA. These compounds also significantly reduced the growth of S. aureus but possessed moderate mammalian toxicity. Furthermore, S. aureus strains treated with these compounds exhibited reduction in adherence to host fibrinogen, as well as biofilm formation. Hence, these compounds may represent an anti-infective therapy without the side effects of antibiotics.     

Enhanced Fluorescence for Bioassembly by Environment‐Switching Doping of Metal Ions

The self‐assembly of cyclodipeptides composed of natural aromatic amino acids into supramolecular structures of diverse morphologies with intrinsic emissions in the visible light region is demonstrated. The assembly process can be halted at the initial oligomerization by coordination with zinc ions, with the most prominent effect observed for cyclo‐dihistidine (cyclo‐HH). This process is mediated by attracting and pulling of the metal ions from the solvent into the peptide environment, rather than by direct interaction in the solvent as commonly accepted, thus forming an “environment‐switching” doping mechanism. The doping induces a change of cyclo‐HH molecular configurations and leads to the formation of pseudo “core/shell” clusters, comprising peptides and zinc ions organized in ordered conformations partially surrounded by relatively amorphous layers, thus significantly enhancing the emissions and allowing the application of the assemblies for ecofriendly color‐converted light emitting diodes. These findings shed light into the very initial coordination procedure and elucidate an alternative mechanism of metal ions doping on biomolecules, thus presenting a promising avenue for integration of the bioorganic world and the optoelectronic field.     

Spousal negative responses to cancer patients: The role of social restriction, spouse mood, and relationship satisfaction.

This cross-sectional study examined perceptions of spousal negative behaviors in 219 cancer patients. A mediational model was proposed to explain why a spouse might respond negatively to an ill partner because of greater restriction on activities as functional impairment increases. A moderating effect of the spouse's marital satisfaction assessed 3 months before other study measures was also proposed. Results provided support for the proposed model. The relationship between increasing patient functional impairment and spousal negative behaviors was mediated by greater restriction in spouse activities, as well as spousal negative mood. A marginally significant moderating effect for marital satisfaction was found. Although these results must be replicated with a prospective study, the findings begin to shed light on why spouses might respond in negative ways to an ill partner. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Coupling of physical and chemical mechanisms of colloid straining in saturated porous media

Filtration theory does not include the potential influence of pore structure on colloid removal by straining. Conversely, previous research on straining has not considered the possible influence of chemical interactions. Experimental and theoretical studies were therefore undertaken to explore the coupling of physical and chemical mechanisms of colloid straining under unfavorable attachment conditions (pH=10). Negatively charged latex microspheres (1.1 and 3mum) and quartz sands (360, 240, and 150mum) were used in packed column studies that encompassed a range in suspension ionic strengths (6-106mM) and Darcy water velocities (0.1-0.45cmmin(-1)). Derjaguin-Landau-Verwey-Overbeek (DLVO) calculations and torque analysis suggests that attachment of colloids to the solid-water interface was not a significant mechanism of deposition for the selected experimental conditions. Effluent concentration curves and hyperexponential deposition profiles were strongly dependent on the solution chemistry, the system hydrodynamics, and the colloid and collector grain size, with greater deposition occurring for increasing ionic strength, lower flow rates, and larger ratios of the colloid to the median grain diameter. Increasing the solution ionic strength is believed to increase the force and number of colloids in the secondary minimum of the DLVO interaction energy profile. These weakly associated colloids can be funneled to small regions of the pore space formed adjacent to grain-grain junctions. For select systems, the ionic strength of the eluant solution was decreased to 6mM following the recovery of the effluent concentration curve. In this case, only a small portion of the deposited colloids was recovered in the effluent and the majority was still retained in the sand. These observations suggest that the extent of colloid removal by straining is strongly coupled to solution chemistry.     

Diversity of Campylobacter isolates from retail poultry carcasses and from humans as demonstrated by pulsed-field gel electrophoresis

Campylobacter spp. are a major contaminant of poultry. Eating undercooked chicken and handling raw poultry have been identified as risk factors for campylobacteriosis in humans. Previous studies have found Campylobacter spp. on 90% of poultry carcasses. In the present study, pulsed-field gel electrophoresis (PFGE) was used to assess the genetic diversity of strains on retail poultry carcasses. PFGE patterns of isolates from campylobacteriosis cases were compared to those from the poultry isolates. Over a 1-year study period (March 2000 through February 2001), whole fresh young chickens (n = 72) were obtained from three retail outlets in an urban community in the south-central United States. Campylobacter spp. were isolated from 82% of these carcasses. Strains (n = 70) were defined on the basis of their PFGE pattern. Sixty-seven percent of the carcasses from which Campylobacter spp. were isolated were contaminated with more than one PFGE-distinguishable strain. During the 1-year study period, most of the PFGE patterns (59%) were limited to isolates obtained from a single carcass. Forty-one percent of the PFGE-distinguishable strains were recovered from more than one carcass. Ninety-seven percent of the carcasses contaminated with the same strain were purchased at the same time from the same store. To examine the degree of genetic stability, four strains were followed in vitro over an estimated 1,000 doublings. The PFGE pattern of one of these isolates underwent minor changes during in vitro growth. The data indicate extensive variability in the PFGE patterns of Campylobacter spp. isolated from humans and from poultry carcasses. In spite of difficulties caused by such diversity and the fact that some carcasses are contaminated with more than one strain, the pattern variation provides a useful method for linking a particular strain to its source.     

Thermal inactivation of Enterobacter sakazakii in rehydrated infant formula

The presence of low levels of Enterobacter sakazakii in dried infant formula have been linked to outbreaks of meningitis, septicemia, and necrotizing enterocolitis in neonates, particularly those who are premature or immunocompromised. In the current study, the ability of 12 strains of E. sakazakii to survive heating in rehydrated infant formula was determined at 58 degrees C with a submerged coil apparatus. The observed D58-values ranged from 30.5 to 591.9 s, with the strains appearing to fall into two distinct heat resistance phenotypes. The z-value of the most heat-resistant strain was 5.6 degrees C. When dried infant formula containing this strain was rehydrated with water preequilibrated to various temperatures, a more than 4-log reduction in E. sakazakii levels was achieved by preparing the formula with water at 70 degrees C or greater.     

Evaluation of different methods for the detection and identification of Enterobacter sakazakii isolated from South African infant formula milks and the processing environment

Enterobactersakazakii is an emerging pathogen associated with life-threatening neonatal infections resulting from the consumption of contaminated powdered infant formula milk (IFM). Recent taxonomic analyses have determined that E. sakazakii comprises a number of genomospecies, and it has been proposed that E. sakazakii be reclassified as a novel genus, "Cronobacter". Accurate methods are required for the rapid detection and identification of this group of micro-organisms, since even low cell numbers have been reported to cause disease. The aim of this study was to evaluate various E. sakazakii detection methods in order to ascertain the most suitable method for detection and identification of these pathogenic agents. Samples from IFM and the environment were evaluated for the presence of E. sakazakii using the isolation steps (pre-enrichment, enrichment and selection) described in the Food and Drug Administration (FDA) method for E. sakazakii detection. Sixty-four isolates (50 from IFM and 14 from the environment) were selected from tryptone soy agar (TSA), regardless of colony appearance, and these isolates were identified by 16S ribosomal DNA (rDNA) sequencing. Thereafter, different culture-dependent and culture-independent methods were evaluated to accurately detect and identify the E. sakazakii isolates. These methods included the assessment of yellow pigment production on TSA, typical colonies on chromogenic Druggan-Forsythe-Iversen (DFI) and Chromocult(R) Enterobacter sakazakii (CES) media and polymerase chain reaction (PCR) using six different species-specific primer pairs described in the literature. Identification of E. sakazakii using yellow pigment production was demonstrated to have a low sensitivity, specificity and accuracy (87%, 71% and 74%, respectively), which lowers the suitability of the FDA method. Chromogenic DFI and CES media were sensitive, specific and accurate (100%, 98% and 98%, respectively) for the detection of E. sakazakii. The specificity of the PCR amplifications ranged from 8% to 92%, emphasising the need for rigorous primer testing against closely related species. Of the primer pairs evaluated, Esakf/Esakr were the most suitable for E. sakazakii detection and identification. The detection limit of Esakf/Esakr was found to be 10(4) CFU/ml. This study demonstrated that no single method was capable of unambiguously confirming the presence and identity of E. sakazakii isolates, that each method had inherent advantages and disadvantages, and that in most cases several methods were required for accurate detection and identification. Further, it was demonstrated that the current FDA method for E. sakazakii detection should be revised in the light of the availability of more sensitive, specific and accurate detection methods.