The Subgingival Microbiota in older subjects. Impact of Chlorhexidine Rinsing

Background: Periodontitis and caries are common diseases in older adults. Aims: To test if rinsing with chlorhexidine over five years has an impact on the subgingival microbiota. Methods: In a double blind randomized five years chlorhexidine rinse study clinical oral data and subgingival plaque samples were analyzed by the checkerboard DNA-DNA hybridization method. Results: At year 5 subject mean age was 71.2 years (S.D. + 4.1) (56.2% women). Only in subjects with no bone loss did the chlorhexidine rinse group subjects presented with lower total bacterial (DNA) counts (mean diff: 63.1 (x105), S.E diff + 30.1 (x105), 95%CI: 0.8 to 120.5 (x105), p<0.05) [(i.e.Lactobacillus acidophilicus (p<0.05) , Streptococcus oralis (p<0.05), Eikenella. corrodens (p< 0.05), C. gracilis (p<0.01), F.nucl.sp. nucleatum (p< 0.02), Fusobacterium nucl. sp. polymorphum (p<0.02), Neisseria mucosa (p<0.02), Leptothrichia buccalis (p<0.02), and Selenomonas noxia (p<0.050)]. Higher bacterial loads were found for the green (p<0.05), yellow (streptococci spp) (p<0.01), and the ‘other' complexes (p<0.01). Conclusions: Independent of probing pocket depth, older subjects carry a large variety of bacteria associated with periodontitis. The oral microbiota in older subjects is linked to alveolar bone loss and not to probing depth. Chlorhexidine may provide a benefit in preventing periodontitis in older persons.

The impact of a low-frequency chlorhexidine rinsing schedule on the subgingival microbiota (the TEETH clinical trial)

BACKGROUND: Information on the efficacy of chlorhexidine (CHX) rinsing on the subgingival microbiota is limited. This study tested if intermittent CHX rinsing over 5 years had an impact on the subgingival microbiota. METHODS: Subgingival plaque samples were analyzed by the checkerboard DNA-DNA hybridization method in a double-blind randomized CHX rinse study. RESULTS: A total of 210 subjects were included. The mean age of the subjects was 71.7 (+/- 4.1) years, and 56.2% were women. Evidence of alveolar bone loss was found in 39% of subjects. Bacterial loads were not correlated significantly with probing depth. At year 5, subjects in the CHX rinse group with no evidence of bone loss presented with lower total bacterial counts than control subjects with no bone loss. The levels of the following bacteria were significantly lower in the CHX group: Lactobacillus acidophilus (P <0.05), Eikenella corrodens (P <0.05), Fusobacterium nucleatum sp. nucleatum (P <0.01), Treponema denticola (P <0.05), Leptotrichia buccalis (P <0.05), and Eubacterium saburreum (P <0.05). No differences in bacterial loads were found between CHX and control rinse subjects with alveolar bone loss. CONCLUSIONS: Older subjects with or without periodontitis carry a large variety of bacteria associated with periodontitis. Intermittent rinsing with CHX may provide a preventive benefit in reducing levels of bacteria but only in subjects without alveolar bone loss.

Mechanical chondroplasty: early metabolic consequences in vitro

PURPOSE: The purpose of this study was to determine the depth of penetration from mechanical chondroplasty and metabolic consequences of this procedure on the remaining articular cartilage. METHODS: Mechanical chondroplasty was performed in vitro on a portion of fresh grade I or II articular cartilage from 8 human knee arthroplasty specimens. Treated and control (untreated) explants (approximately 30 mg) were cut from the cartilage. The explants were divided into 2 groups, day 1 and day 4, placed separately in a 48-well plate containing media, and incubated at 37 degrees C for 24 hours. After the 24-hour incubation, the explants were weighed on day 1 and day 4, and explant media were removed and tested for total proteoglycan synthesis and aggrecan synthesis. At time 0, 2 sets (2.6 mm each) of treated and control cartilage slices were cut with a precision saw. One set was stained for confocal laser microscopy via a cytotoxicity stain to determine cell viability. The second set was stained with H;E to determine depth of penetration. RESULTS: The mean depth of penetration was 252.8 +/- 78 microm. There was no significant difference (P > .25) between total proteoglycan synthesis for control versus treatment groups on day 1 or 4. Aggrecan synthesis was significantly reduced on day 1 when normalized for tissue weight (P = .019) and double-stranded deoxyribonucleic acid (P = .004). On day 4, no significant difference was detected. Confocal laser microscopy did not show cell death below the zone of treatment. CONCLUSIONS: There was no significant metabolic consequence caused by chondroplasty to the remaining articular cartilage, and the zone of injury was limited to the treatment area. CLINICAL RELEVANCE: Mechanical chondroplasty causes no significant metabolic consequences to articular cartilage under these conditions.

Improving the performance of GIS/spatial analysts though novel applications of the Emotiv EPOC EEG headset

Geospatial information systems are used to analyze spatial data to provide decision makers with relevant, up-to-date, information. The processing time required for this information is a critical component to response time. Despite advances in algorithms and processing power, we still have many “human-in-the-loop” factors. Given the limited number of geospatial professionals, analysts using their time effectively is very important. The automation and faster humancomputer interactions of common tasks that will not disrupt their workflow or attention is something that is very desirable. The following research describes a novel approach to increase productivity with a wireless, wearable, electroencephalograph (EEG) headset within the geospatial workflow.

High temperature, low cycle fatigue of a hybrid particulate/fiber aluminum metal-matrix composite

The effect of shot particles on the high temperature, low cycle fatigue of a hybrid fiber/particulate metal-matrix composite (MMC) was studied. Two hybrid composites with the general composition A356/35%SiC particle/5%Fiber (one without shot) were tested. It was found that shot particles acting as stress concentrators had little effect on the fatigue performance. It appears that fibers with a high silica content were more likely to debond from the matrix. Final failure of the composite was found to occur preferentially in the matrix. SiC particles fracture progressively during fatigue testing, leading to higher stress in the matrix, and final failure by matrix overload. A continuum mechanics based model was developed to predict failure in fatigue based on the tensile properties of the matrix and particles. By accounting for matrix yielding and recovery, composite creep and particle strength distribution, failure of the composite was predicted.

Potential for hardware-based techniques for reuse distance analysis

Reuse distance analysis, the prediction of how many distinct memory addresses will be accessed between two accesses to a given address, has been established as a useful technique in profile-based compiler optimization, but the cost of collecting the memory reuse profile has been prohibitive for some applications. In this report, we propose using the hardware monitoring facilities available in existing CPUs to gather an approximate reuse distance profile. The difficulties associated with this monitoring technique are discussed, most importantly that there is no obvious link between the reuse profile produced by hardware monitoring and the actual reuse behavior. Potential applications which would be made viable by a reliable hardware-based reuse distance analysis are identified.

BENEFICIATION OF HIGH-MgO SEDIMENTARY PHOSPHATE ORES

Dolomite [CaMg(CO3)2] is an intolerable impurity in phosphate ores due to its MgO content. Traditionally, the Florida phosphate industry has avoided mining high-MgO phosphate reserves due to the lack of an economically viable process for removal of dolomite. However, as the high grade phosphate reserves become depleted, more emphasis is being put on the development of a cost effective method for separating dolomite from high-MgO phosphate ores. In general, the phosphate industry demands a phosphate concentrate containing less than 1%MgO. Dolomite impurities have mineralogical properties that are very similar to the desired phosphate minerals (francolite), making the separation of the two minerals very difficult. Magnesium is primarily found as distinct dolomite-rich pebbles, very fine dolomite inclusions in predominately francolite pebbles, and magnesium substituted into the francolite structure. Jigging is a gravity separation process that attempts to take advantage of the density difference between the dolomite and francolite pebbles. A unique laboratory scale jig was designed and built at Michigan Tech for this study. Through a series of tests it was found that a pulsation rate of 200 pulse/minute, a stroke length of 1 inch, a water addition rate of 0.5gpm, and alumina ragging balls were optimum for this study. To investigate the feasibility of jigging for the removal of dolomite from phosphate ore, two high-MgO phosphate ores were tested using optimized jigging parameters: (1) Plant #1 was sized to 4.00x0.85mm and contained 1.55%MgO; (2) Plant #2 was sized to 3.40mmx0.85mm and contained 3.07% MgO. A sample from each plant was visually separated by hand into dolomite and francolite rich fractions, which were then analyzed to determine the minimum achievable MgO levels. For Plant #1 phosphate ore, a concentrate containing 0.89%MgO was achieved at a recovery of 32.0%BPL. For Plant #2, a phosphate concentrate containing 1.38%MgO was achieved at a recovery of 74.7%BPL. Minimum achievable MgO levels were determined to be 0.53%MgO for Plant #1 and 1.15%MgO for Plant #2.

Effect of Manganese and Arsenic upon Current Efficiency in the Deposition of Zinc from Zinc Sulphate Solution

Throughout the entire experiment the electrolysis were conducted in an eight-hundred cubic centimeter beaker. An excellent circulation of the solution was assured by means of an electric stirrer, vigorous gas evolution from the anodes, and by means of a regulated feed-discharge system. By means of this balance, solution of the same impurity concentration as that of the electrolyte was fed in the cell just as fast as the discharge was syphoned out.

The Eyes Have It: Regulatory and Structural Changes Both Underlie Cichlid Visual Pigment Diversity

A major goal of evolutionary biology is to unravel the molecular genetic mechanisms that underlie functional diversification and adaptation. We investigated how changes in gene regulation and coding sequence contribute to sensory diversification in two replicate radiations of cichlid fishes. In the clear waters of Lake Malawi, differential opsin expression generates diverse visual systems, with sensitivities extending from the ultraviolet to the red regions of the spectrum. These sensitivities fall into three distinct clusters and are correlated with foraging habits. In the turbid waters of Lake Victoria, visual sensitivity is constrained to longer wavelengths, and opsin expression is correlated with ambient light. In addition to regulatory changes, we found that the opsins coding for the shortest-and longest-wavelength visual pigments have elevated numbers of potentially functional substitutions. Thus, we present a model of sensory evolution in which both molecular genetic mechanisms work in concert. Changes in gene expression generate large shifts in visual pigment sensitivity across the collective opsin spectral range, but changes in coding sequence appear to fine-tune visual pigment sensitivity at the short-and long-wavelength ends of this range, where differential opsin expression can no longer extend visual pigment sensitivity.

The EU’s Trouble with Mashups: From Disabling to Enabling a Digital Art Form

New tools for editing of digital images, music and films have opened up new possibilities to enable wider circles of society to engage in ’artistic’ activities of different qualities. User-generated content has produced a plethora of new forms of artistic expression. One type of user-generated content is the mashup. Mashups are compositions that combine existing works (often) protected by copyright and transform them into new original creations. The European legislative framework has not yet reacted to the copyright problems provoked by mashups. Neither under the US fair use doctrine, nor under the strict corset of limitations and exceptions in Art 5 (2)-(3) of the Copyright Directive (2001/29/EC) have mashups found room to develop in a safe legal environment. The contribution analyzes the current European legal framework and identifies its insufficiencies with regard to enabling a legal mashup culture. By comparison with the US fair use approach, in particular the parody defense, a recent CJEU judgment serves as a comparative example. Finally, an attempt is made to suggest solutions for the European legislator, based on the policy proposals of the EU Commission’s “Digital Agenda” and more recent policy documents (e.g. “On Content in the Digital Market”, “Licenses for Europe”). In this context, a distinction is made between non-commercial mashup artists and the emerging commercial mashup scene.

Ligament origins are preserved in distal radial intraarticular two-part fractures: a computed tomography-based study

Background Operative fixation of intraarticular distal radius fractures is increasingly common. A greater understanding of fracture patterns will aid surgical fixation strategy. Previous studies have suggested that ligamentous insertions may less commonly be involved, but these have included heterogeneous groups of fractures and have not addressed Lister's tubercle. Purpose We hypothesize that fracture lines of distal radial intraarticular 2-part fractures have reproducible patterns. They propagate through the cortical bone between ligament origins and do not involve Lister's tubercle. Methods Axial CT scans of two-part intraarticular distal radius fractures were assessed independently by two examiners. The fractures were mapped onto a grid and the cortical breaches expressed as a percentile of the total radial width or length. The cortical breaches were compared with the ligamentous insertions on the distal and Lister's tubercle. Associated injuries were also documented. Results The cortical breaches occurred between the ligamentous insertions in 85%. Lister's tubercle was not involved in 95% of the fractures. Three major fracture patterns emerged: radial styloid, dorsal, and volar. Each major pattern had two subtypes. Associated injuries were common. Scapholunate dissociation was associated with all types, not just the radial styloid fracture pattern. Conclusions The fracture patterns of two-part intraarticular fractures mostly involved the interligamentous zones. Three major groups were identified: dorsal, volar, and radial styloid. Lister's tubercle was preserved with fractures tending to propagate radial or ulnar to this structure. We suggest conceptualizing fracture fragments as osseo-ligamentous units to aid prediction of fracture patterns and associated injury. Study Design Diagnostic III Level of Evidence 3.

Prion protein glycosylation is not required for strain-specific neurotropism.

In this study, we tested the hypothesis that the glycosylation of the pathogenic isoform of the prion protein (PrP(Sc)) might encode the selective neurotropism of prion strains. We prepared unglycosylated cellular prion protein (PrP(C)) substrate molecules from normal mouse brain by treatment with PNGase F and used reconstituted serial protein cyclic misfolding amplification reactions to produce RML and 301C mouse prions containing unglycosylated PrP(Sc) molecules. Both RML- and 301C-derived prions containing unglycosylated PrP(Sc) molecules were infectious to wild-type mice, and neuropathological analysis showed that mice inoculated with these samples maintained strain-specific patterns of PrP(Sc) deposition and neuronal vacuolation. These results show that PrP(Sc) glycosylation is not necessary for strain-dependent prion neurotropism.

Role of acetyl-phosphate in activation of the Rrp2-RpoN-RpoS pathway in Borrelia burgdorferi.

Borrelia burgdorferi, the Lyme disease spirochete, dramatically alters its transcriptome and proteome as it cycles between the arthropod vector and mammalian host. During this enzootic cycle, a novel regulatory network, the Rrp2-RpoN-RpoS pathway (also known as the σ(54)-σ(S) sigma factor cascade), plays a central role in modulating the differential expression of more than 10% of all B. burgdorferi genes, including the major virulence genes ospA and ospC. However, the mechanism(s) by which the upstream activator and response regulator Rrp2 is activated remains unclear. Here, we show that none of the histidine kinases present in the B. burgdorferi genome are required for the activation of Rrp2. Instead, we present biochemical and genetic evidence that supports the hypothesis that activation of the Rrp2-RpoN-RpoS pathway occurs via the small, high-energy, phosphoryl-donor acetyl phosphate (acetyl∼P), the intermediate of the Ack-Pta (acetate kinase-phosphate acetyltransferase) pathway that converts acetate to acetyl-CoA. Supplementation of the growth medium with acetate induced activation of the Rrp2-RpoN-RpoS pathway in a dose-dependent manner. Conversely, the overexpression of Pta virtually abolished acetate-induced activation of this pathway, suggesting that acetate works through acetyl∼P. Overexpression of Pta also greatly inhibited temperature and cell density-induced activation of RpoS and OspC, suggesting that these environmental cues affect the Rrp2-RpoN-RpoS pathway by influencing acetyl∼P. Finally, overexpression of Pta partially reduced infectivity of B. burgdorferi in mice. Taken together, these findings suggest that acetyl∼P is one of the key activating molecule for the activation of the Rrp2-RpoN-RpoS pathway and support the emerging concept that acetyl∼P can serve as a global signal in bacterial pathogenesis.