The Porphyromonas gingivalis hemagglutinins HagB and HagC are major mediators of adhesion and biofilm formation

Porphyromonas gingivalis is a bacterium associated with chronic periodontitis that possesses a family of genes encoding hemagglutinins required for heme acquisition. In this study we generated ΔhagB and ΔhagC mutants in strain W83 and demonstrate that both hagB and hagC are required for adherence to oral epithelial cells. Unexpectedly, a double ΔhagB/ΔhagC mutant had less severe adherence defects than either of the single mutants, but was found to exhibit increased expression of the gingipain-encoding genes rgpA and kgp, suggesting that a ΔhagB/ΔhagC mutant is only viable in populations of cells that exhibit increased expression of genes involved in heme acquisition. Disruption of hagB in the fimbriated strain ATCC33277 demonstrated that HagB is also required for stable attachment of fimbriated bacteria to oral epithelial cells. Mutants of hagC were also found to form defective single and multi-species biofilms that had reduced biomass relative to biofilms formed by the wild-type strain. This study highlights the hitherto unappreciated importance of these genes in oral colonization and biofilm formation

Measuring-up in timber: A critical perspective on mid-and high-rise timber building design

Architects, engineers and researchers alike often cite practical reasons for building with wood. Since the development of curved glulam beams and columns over a century ago, the widespread use of massive structural timber elements has allowed architects and engineers to design and build in wood with unprecedented speed and scale. Moreover, rising concerns of climate change and the carbon-dioxide emissions associated with construction encourage the use of wood as a viable alternative to steel and concrete, due to CO2 sequestration in trees.In mid- and high-rise buildings, the current shift from steel and concrete towards massive structural timber elements like glulam, laminated-veneer lumber (LVL) and cross-laminated timber (CLT) is evident in a number of recently completed timber buildings in Europe, ranging from seven to nine storeys. Several speculative design proposals have also been made for ‘timber towers’ of thirty, fortytwo and even sixty-five storeys, recognising that designing with massive structural timber elements in high-rise buildings is still in its infancy. This paper offers a new perspective on building with wood at this scale, beyond carbon sequestrationand construction.This is the author's accepted manuscript. The final version has been published in Architectural Research Quarterly here: http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=9295856&fileId=S1359135514000268. Copyright © Cambridge University Press 201

A County by County Analysis of Poverty in the State of Georgia

The state of Georgia has one of the highest poverty rates of all the states in the United States. This study examines the causes of poverty in Georgia, using county-level data. The state of Georgia is one of the largest states in the Southeastern U.S. and is very diverse in terms of its mix of metropolitan and non-metropolitan counties, and its mix of agricultural and non-agricultural counties. The major focus of the paper is determining the effect that demographic, educational attainment, labor force, government assistance, and transportation characteristics of a county have on its poverty rate. The major findings of this paper are that counties located in Metropolitan Statistical Areas (MSA) have a much lower poverty rate than the state average, micropolitan statistical areas and counties that’re classified in neither an MSA or a micrpolitan statistical area. Counties that have a higher black population also have a higher poverty rate when holding all else constant. Attempts to reduce the poverty rate should consider increasing educational attainment, shying away from encouraging Retail Trade jobs from entering counties, encouraging the creation of more commuter zones and boosting the per capita net earnings of the county

UK utility data integration: overcoming schematic heterogeneity

In this paper we discuss syntactic, semantic and schematic issues which inhibit the integration of utility data in the UK. We then focus on the techniques employed within the VISTA project to overcome schematic heterogeneity. A Global Schema based architecture is employed. Although automated approaches to Global Schema definition were attempted the heterogeneities of the sector were too great. A manual approach to Global Schema definition was employed. The techniques used to define and subsequently map source utility data models to this schema are discussed in detail. In order to ensure a coherent integrated model, sub and cross domain validation issues are then highlighted. Finally the proposed framework and data flow for schematic integration is introduced

A moving mesh method for modelling defects in nematic liquid crystals

The properties of liquid crystals can be modelled using an order parameter which describes the variability of the local orientation of rod-like molecules. Defects in the director field can arise due to external factors such as applied electric or magnetic fields, or the constraining geometry of the cell containing the liquid crystal material. Understanding the formation and dynamics of defects is important in the design and control of liquid crystal devices, and poses significant challenges for numerical modelling. In this paper we consider the numerical solution of a Q-tensor model of a nematic liquid crystal, where defects arise through rapid changes in the Q-tensor over a very small physical region in relation to the dimensions of the liquid crystal device. The efficient solution of the resulting six coupled partial differential equations is achieved using a finite element based adaptive moving mesh approach, where an unstructured triangular mesh is adapted towards high activity regions, including those around defects. Spatial convergence studies are presented using a stationary defect as a model test case, and the adaptive method is shown to be optimally convergent using quadratic triangular finite elements. The full effectiveness of the method is then demonstrated using a challenging two-dimensional dynamic Pi-cell problem involving the creation, movement, and annihilation of defects

Effects of Disturbance and Conspecific Negative Density Dependence on Forest Composition and Diversity: A Simulation-Based Approach

Forests provide a wide range of services to humans and create critical habitat for countless species. Tree species composition and diversity, key attributes of forest health and identity, are influenced by both disturbance and conspecific negative density dependence (CNDD). These factors have been thoroughly researched in isolation, but much less is known about how they interact. We present results of a simulation model constructed to investigate the interactions of variable CNDD strengths and disturbance types. We found that while CNDD consistently increased diversity, the magnitude of this effect was heavily influenced by the disturbance regime. The difference between weak and strong CNDD was most pronounced with understory disturbance, and the greatest diversity overall was achieved when strong CNDD was paired with understory disturbance. Empirical studies of CNDD have yielded widely divergent results. Our study suggests a comprehensive understanding of forest ecosystems may require simultaneous consideration of both disturbance and CNDD

Efficacy of rifampicin combination therapy for the treatment of enterococcal infections assessed in vivo using a Galleria mellonella infection model.

Enterococci are a leading cause of healthcare-associated infection worldwide and display increasing levels of resistance to many of the commonly used antimicrobials, making treatment of their infections challenging. Combinations of antibiotics are occasionally employed to treat serious infections, allowing for the possibility of synergistic killing. The aim of this study was to evaluate the effects of different antibacterial combinations against enterococcal isolates using an in vitro approach and an in vivo Galleria mellonella infection model. Five Enterococcus faecalis and three Enterococcus faecium strains were screened by paired combinations of rifampicin, tigecycline, linezolid or vancomycin using the chequerboard dilution method. Antibacterial combinations that displayed synergy were selected for in vivo testing using a G. mellonella larvae infection model. Rifampicin was an effective antibacterial enhancer when used in combination with tigecycline or vancomycin, with minimum inhibitory concentrations (MICs) of each individual antibiotic being reduced by between two and four doubling dilutions, generating fractional inhibitory concentration index (FICI) values between 0.31 and 0.5. Synergy observed with the chequerboard screening assays was subsequently observed in vivo using the G. mellonella model, with combination treatment demonstrating superior protection of larvae post-infection in comparison with antibiotic monotherapy. In particular, rifampicin in combination with tigecycline or vancomycin significantly enhanced larvae survival. Addition of rifampicin to anti-enterococcal treatment regimens warrants further investigation and may prove useful in the treatment of enterococcal infections whilst prolonging the clinically useful life of currently active antibiotics

Crucial first 48 hours after a crime has been committed?

Police tried and tested methods over many decades are still important in our high-tech age. The first 48 hours after police discover that a crime has been committed are said to be crucial for gathering vital evidence. After then, it becomes more difficult to gather good evidence and the likelihood of that perpetrator being caught is diminished, it has been believed. However, in modern times, police must keep up with forensic science methods and be aware of all current updated protocols and procedures in their jurisdiction