Fluoridated elastomers: effect on disclosed plaque

OBJECTIVE: To investigate the effect of fluoridated elastomers on the quantity of disclosed dental plaque surrounding an orthodontic bracket in vivo. DESIGN: A randomized, prospective, longitudinal clinical trial, employing a split mouth, crossover design. Setting: The Orthodontic Departments of Liverpool and Sheffield Dental Hospitals. Subjects and methods: The subjects were 30 individuals about to start fixed orthodontic treatment. The study consisted of two experimental periods of 6 weeks with a washout period between. Fluoridated elastomers were randomly assigned at the first visit to be placed around brackets on 12, 11, 33 or 22, 21, 43. Non-fluoridated elastomers were placed on the contra-lateral teeth. After 6 weeks (visit 2) the elastomers were removed, the teeth disclosed and a photograph taken. Non-fluoridated elastomers were placed on all brackets for one visit to allow for a washout period. At visit 3, fluoridated elastomers were placed on the contra-lateral teeth to visit 1. At visit 4, the procedures at visit 2 were repeated. The photographs were scanned, then the area and proportion of the buccal surface covered with disclosed plaque was measured using computerized image analysis. A mixed-effects ANOVA was carried out with the dependent variable being the area or percentage area of disclosed plaque. RESULTS: There was no evidence of a systematic error and substantial agreement for the repeat readings of the same images. The only significant independent variable for the area of disclosed plaque was the subject (p<0.001). The significant independent variables for the proportion of disclosed plaque were the subject (p<0.001) and the tooth type (p=0.002). The independent variable describing the use of fluoridated or non-fluoridated elastomers was not significant for either the area or the proportion of disclosed plaque. CONCLUSION: Fluoridated elastomers do not affect the quantity of disclosed plaque around an orthodontic bracket

A study of some peculiar tropical risk factors for proteinuriaas marker of chronic kidney disease in a rural community in Ondo state, south-west Nigeria

Background: The role of herbal remedies and Non-Steroidal Anti-inflammatory Drugs in the development and progression of chronic kidney disease are yet to be fully studied in our environment despite their indiscriminate use. We set out to determine the prevalence and pattern of use of herbal remedies and NSAIDs and their relationship (if any) to chronic kidney disease.Methods: Adults at a screening exercise in a village in Ondo State, Nigeria were studied. Their bio-data, history of herbal usage and NSAIDs, cigarette smoking, alcohol intake, diabetes mellitus and essential hypertension were obtained. Their blood pressure and anthropometry were measured. Urinalysis was conducted with Combi-Uriscreen®. Data was analysed using SPSS 20.Results: One hundred and sixteen subjects were studied (M:F, 1:1.8). 51.7% were farmers. Their mean age was 42.5±14.7 years (range, 17-78 years). Their mean systolic and diastolic blood pressures were 125.2±20.4mmHg and  77.3±12.3mmHg respectively. Their mean body mass index was 26.2±6.0 kg/m2. Usage of herbs was found among 78.4% of subjects. 68.1% used NSAIDs, 11.2% had a history of cigarette smoking, 25.0% used alcohol, 50.0% had  pre-hypertension, 28.0% had essential hypertension and 7.8% had diabetes  mellitus. Undiagnosed hypertension was present in 24.1%. Proteinuria (ranging between 100mg/dl and 500mg/dl) was present in 12.5% of the subjects. Central obesity was present in 21.9% of the subjects. There was a significant association between proteinuria and use of herbs (p=0.023, chi square 5.188), use of NSAIDs (p=0.01, chi square 6.722), and pre-hypertension (p=0.039, chi square 4.261).Conclusion: The rates of use of herbal remedies and NSAIDs in the rural community are high. Our study suggests that they may cause significant proteinuria among users. There is therefore a need to conduct more high powered studies on this subject.Keywords:herbal concoction, renal failure, tropics, proteinuria, Nigeri

Selenium fractionation and cycling in the intertidal zone of the Carquinez Strait. Quarterly progress report, January 1996--March 1996

This quarterly report describes research on selenium (Se) cycling in the marshes and mudflats of the Carquinez Strait between January 1, 1996 and March 31, 1996. Chapter 2 contains descriptions of results of extractions and analyses of sediment cores from the intertidal zone of the Martinez and Benicia field sites, including some x-ray spectroscopy data related to the characterization of the sediment Eh-pH regime. Chapter 3 contains a summary of work in progress on the extraction of various Se species from sediment/soil samples, and efforts in measuring suspended sediment Se. Chapter 4 is an update on stable Se isotope research and Se purification techniques. Chapter 5 describes the rationale, design, and preliminary results of a plant-Se study. Chapter 6 presents the design of a recently initiated sediment dynamics study. The leader is referred to the 1995 Annual Report for details on the project design, site selection, and methodology

Assessment of trace metals in drinking water and groundwater sources in Ota, Nigeria

The levels of six trace metals namely iron, lead, manganese, copper, zinc and nickel were investigated in drinking water and groundwater sources in Ota, Nigeria. Detected concentrations of Mn, Cu and Zn were below the World Health organization and Standard Organization of Nigeria maximum permissible limits. Fe (92%) and Ni (53%) in some drinking water and groundwater sources were found in concentrations that exceeded the maximum permissible limits for these metals. Notably, the levels of Pb were below detection limit in all the bottled, well and borehole water, with exception of the hospital borehole, while the swimming pool had high concentrations of Fe (0.88 mg/L), Pb (0.21 mg/L) and Ni (0.19mg/L) compared to SON (0.30 mg/L), WHO (0.01 mg/L) and WHO (0.07 mg/L) respectively. Pollution indices indicated significant pollution of Pb, Fe and Ni. Overall, the mean metal levels in the sampled water sources followed a descending order, Fe>Cu>Zn>Ni>Pb>Mn. Some of the drinking water and groundwater sources could be considered safe for drinking, but proactive measures should be taken to check the levels of Fe, Pb and Ni in the swimming pool

Photosynthesis

Although there has been considerable progress toward an understanding of the processes of photosyntehsis in recent years, the advances have been followed rather lcosely by symposia, monographs and reviews of the subject matter, particularly during the last three years. In view of the comprehensive coverage it would appear that the present review might very well be limited to a discussion of certain subjects of special interest to the authors and some with which they are especially familiar. These are (1) the extensive discussion by Warburg and his co-workers of their proposal for the existence of a light induced oxygen absorption (and corresponding carbon dioxide evolution) which can amount to three or four times the net oxygen evolution by the same light; and (2) the discovery of the early participation of 7 and 5 carbon sugars in carbon dioxide reduction in photosyntehsis together with some observations on the kinetics of the metabolic transformations. While it is true that a considerable number of significant publications have appears in other aspects of photosynthesis (the Hill reaction and its coupling with carbon dioxide reduction; photochemistry of chlorophyll and related synthetic materials as model reactions in relatively simple defined physical systems; transfer of light energy within the pigment systems) it is felt that they represent confirmation and extension of ideas which have already been discussed in a variety of earlier reviews and that a re-evaluation of them might very well be postponed until a later time

Cosmology and Fermion Confinement in a Scalar-Field-Generated Domain Wall Brane in Five Dimensions

We consider a brane generated by a scalar field domain wall configuration in 4+1 dimensions, interpolating, in most cases, between two vacua of the field. We study the cosmology of such a system in the cases where the effective four-dimensional brane metric is de Sitter or anti de Sitter, including a discussion of the bulk coordinate singularities present in the de-Sitter case. We demonstrate that a scalar field kink configuration can support a brane with dS$_4$ cosmology, despite the presence of coordinate singularities in the metric. We examine the trapping of fermion fields on the domain wall for nontrivial brane cosmology.Comment: 29 pages, 12 figures; minor changes, accepted by JHE

The Effect of Stochastic Noise on Quantum State Transfer

We consider the effect of classical stochastic noise on control laser pulses used in a scheme for transferring quantum information between atoms, or quantum dots, in separate optical cavities via an optical connection between cavities. We develop a master equation for the dynamics of the system subject to stochastic errors in the laser pulses, and use this to evaluate the sensitivity of the transfer process to stochastic pulse shape errors for a number of different pulse shapes. We show that under certain conditions, the sensitivity of the transfer to the noise depends on the pulse shape, and develop a method for determining a pulse shape that is minimally sensitive to specific errors.Comment: 10 pages, 9 figures, to appear in Physical Review

Theoretical models of the halo occupation distribution : separating central and satellite galaxies

The halo occupation distribution (HOD) describes the relation between galaxies and dark matter at the level of individual dark matter halos. The properties of galaxies residing at the centers of halos differ from those of satellite galaxies because of differences in their formation histories. Using a smoothed particle hydrodynamics (SPH) simulation and a semianalytic (SA) galaxy formation model, we examine the separate contributions of central and satellite galaxies to the HOD, more specifically to the probability P(N|M) that a halo of virial mass M contains N galaxies of a particular class. In agreement with earlier results for dark matter subhalos, we find that the mean occupation function langNrangM for galaxies above a baryonic mass threshold can be approximated by a step function for central galaxies plus a power law for satellites and that the distribution of satellite numbers is close to Poisson at fixed halo mass. Since the number of central galaxies is always zero or one, the width of P(N|M) is narrower than a Poisson distribution at low N and approaches Poisson at high N. For galaxy samples defined by different baryonic mass thresholds, there is a nearly linear relation between the minimum halo mass Mmin required to host a central galaxy and the mass M1 at which an average halo hosts one satellite, with M1 ≈ 14Mmin (SPH) or M1 ≈ 18Mmin (SA). The stellar population age of central galaxies correlates with halo mass, and this correlation explains much of the age dependence of the galaxy HOD. The mean occupation number of young galaxies exhibits a local minimum at M ~ 10Mmin where halos are too massive to host a young central galaxy but not massive enough to host satellites. Using the SA model, we show that the conditional galaxy mass function at fixed halo mass cannot be described by a Schechter function because central galaxies produce a "bump" at high masses. We suggest parameterizations for the HOD and the conditional luminosity function that can be used to model observed galaxy clustering. Many of our predictions are in good agreement with recent results inferred from clustering in the Sloan Digital Sky Survey

Dataset on phytochemical screening, FTIR and GC–MS characterisation of Azadirachta indica and Cymbopogon citratus as reducing and stabilising agents for nanoparticles synthesis

The dataset for this article contains phytochemical and FTIR data for three different extracts from two indigenous medicinal plants obtained from Ogun State, Southwest Nigeria and the GC–MS characterisation data for their ethanolic extracts. To obtain this data, the leaves of Azadirachta indica and Cymbopogon citratus were collected from the premises of Covenant University, Nigeria. The plants were dried, pulverized and extracted with ethanol, distilled water and ethanol:water (50:50), before phytochemical screening (qualitative and quantitative), FTIR and GC–MS analyses were carried out. The dataset provides insight into the presence of bioactive phyto-constituents such as polyphenols and tannins as potential precursors for green-based nanoparticle synthesis

Biogenic iron oxide nanoparticles and activated sodium persulphate for hydrocarbon remediation in contaminated soil

Biogenic iron oxide nanoparticles synthesized from a locally sourced, readily available plant — Azadirachta indica, were used synergistically with sodium persulphate (PS) to degrade total petroleum hydrocarbons (TPHs) in contaminated soil. A chemometric approach to optimizing the conditions for the degradation of TPH was developed using central composite design (CCD). Characterization of iron oxide nanoparticles was carried out with X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy, Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and selected electron area diffraction (SAED). Analysis of TPH was carried out with gas chromatography flame ionization detector (GC-FID). The optimum condition for the complete degradation of TPH was achieved at pH 6.0 and oxidant dosage of 0.74 M within 14 h and 5 days. Iron nanoparticles AZA FeNP (1:1) and AZA FeNP (2:1) were synthesized by varying the ratio of extract/precursor. The nanoparticles displayed heterogeneous, amorphous morphology with increased agglomeration in AZA FeNP (1:1). AZA FeNP (2:1) XRD spectra exhibited characteristic peaks at 27.0◦, 35.4◦ and 44.5◦, which are attributed to iron nanoparticles. TEM and HR-TEM images confirmed spherical nanoclusters’ presence with an average size of 9.3 and 10.0 nm for AZA FeNP (1:1) and AZA FeNP (2:1), respectively. The EDX spectra displayed intense peaks of oxygen, carbon, and iron at 0.4, 0.6 and 6.4 KeV confirming the presence of FeNP. Under optimized conditions, PS alone degraded 68% TPH while 0.07 and 0.15 g/L FeNP achieved ∼93 and 95% degradation, respectively. Additionally, 0.07 and 0.15 g/L FeNP-activated PS achieved ∼99 and 100% TPH degradation, respectively. The outcome of these findings suggests that FeNP synthesized using A. indica successfully catalyzed PS for complete degradation of TPH in crude oil-contaminated soil