Magnetoelectric properties of magnetite thin films

Resistivity, DC Hall effect and transverse magnetoresistance measurements were made on polycrystalline thin films of magnetite (Fe3O4) from 104K to room temperature. The Verwey transition is observed at TV=123K, about 4K higher than reported for bulk magnetite. The ordinary and extraordinary Hall coefficients are negative over the entire temperature range, consistent with negatively charged carriers. The extraordinary Hall coefficient exhibits a rho 1/3 dependence on the resistivity above TV and a rho 2/3 dependence below TV. The magnetoresistance is negative at all temperatures and for all magnetic field strengths. The planar Hall effect signal was below the sensitivity of the present experiment

Effect of dimethyl sulfoxide on dentin collagen

Objectives. Infiltration of adhesive on dentin matrix depends on interaction of surface and adhesive. Interaction depends on dentin wettability, which can be enhanced either by increasing dentin surface energy or lowering the surface energy of adhesive. The objective was to examine the effect of dimethyl sulfoxide (DMSO) on demineralized dentin wettability and dentin organic matrix expansion. Methods. Acid-etched human dentin was used for sessile drop contact angle measurement to test surface wetting on 1-5% DMSO-treated demineralized dentin surface, and linear variable differential transformer (LVDT) to measure expansion/shrinkage of dentinal matrix. DMSO-water binary liquids were examined for surface tension changes through concentrations from 0 to 100% DMSO. Kruskal-Wallis and Mann-Whitney tests were used to test the differences in dentin wettability, expansion and shrinkage, and Spearman test to test the correlation between DMSO concentration and water surface tension. The level of significance was p 80%) DMSO concentrations which expanded demineralized dentin more than water. Drying times of LVDT samples increased significantly with the use of DMSO. Significance. Increased dentin wettability may explain the previously demonstrated increase in adhesive penetration with DMSO-treated dentin, and together with the expansion of collagen matrix after drying may also explain previously observed increase in dentin adhesive bonding. (C) 2017 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.Peer reviewe

Cytotoxicity of dental composites and other materials in a new in vitro device

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73901/1/j.1600-0714.1988.tb01304.x.pd

128-bit multicomparator

A 128-bit multicomparator was designed to perform the search-sort function on arbitrary length data strings. Devices can be cascaded for longer block lengths or paralleled for bit-parallel, word-serial applications. The circuit utilizes a 3-phase static-dynamic shift register cell for data handling and a unique gated EXCLUSIVE-NOR circuit to accomplish the compare function. The compare operation is performed bit parallel between a `data' register and a `key' register with a third `mask' register containing DON'T CARE bits that disable the comparator. The multicomparator was fabricated using p-channel silicon-gate metal-oxide-semiconductor (MOS) technology on a 107/spl times/150 mil chip containing 3350 devices. With transistor-transistor logic (TTL) input, data rates in excess of 2 MHz have been attained. The average power dissipation was 250 mW in the dynamic mode and 300 mW in the static mode

The Influence Of Tubule Density And Area Of Solid Dentin On Bond Strength Of Two Adhesive Systems To Dentin.

To determine the correlation between the tubule density (TD) and the area occupied by solid dentin (ASD) with the bond strength of one conventional and one self-etching adhesive system to dentin. The crown of extracted human third molars was transversally sectioned with a diamond saw to expose either superficial, middle, or deep dentin. The three groups of dentin surfaces were randomly divided and bonded with either Clearfil Liner Bond 2V (LB) or Prime & Bond 2.1 (PB) adhesive systems according to manufacturer's directions. Resin composite buildup crowns (10.0 mm high) were incrementally constructed on the bonded surfaces and the teeth stored in water at 37 degrees C. After 24 h of storage, the teeth were vertically, serially sectioned in both x and y directions to obtain several bonded sticks of approximately 0.7 mm2 cross-sectional area. Each stick was tested in tension in a EMIC DL-500 tester at 0.5 mm/min until failure. After testing, the dentin side of the fractured specimen was gently abraded with a 1000-grit SiC paper, etched with 37% phosphoric acid for 15 s and allowed to air dry. SEM micrographs at 1000x and 4000x magnification were taken to permit calculation of the TD (number of tubules/mm2) and ASD (% of total area) at the site of fracture. Correlation between TD and ASD with the bond strength data was performed by linear regression. All statistical analysis was done with alpha = 0.05. Overall bond strength (MPa) for LB was 26.0 +/- 10.2, and 42.6 +/- 15.2 for PB. There was a significant direct relationship between bond strength and ASD for both materials (r2 = 0.20, p 0.05). Mean bond strength of PB was significantly higher than LB for both superficial and middle dentin (p 0.05). Regional variations in TD and ASD may modify bond strength of both conventional and self-etching adhesive systems. Bonding sites with larger ASD seem to yield higher bond strengths regardless of the type of adhesive system used.3315-2

Characterization of the “in vitro pulp chamber” using the cytotoxicity of phenol

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71980/1/j.1600-0714.1989.tb00744.x.pd

Use of crosslinkers to inactivate dentin MMPs

Objectives. This study evaluated the endogenous matrix metalloproteinase (MMP) activity of demineralized dentin matrix following 1 or 5 min pretreatment by various collagen crosslinkers. Generic MMP activity assay, total protein analysis, in situ zymography, gelatin zymography and multiplex bead technology were used to evaluate matrix-bound MMP activity. Methods. Six different crosslinkers; glutaraldehyde, riboflavin/UVA, riboflavin-5-monophospate/UVA, sumac berry extract, grape seed extract, and curcumin were used. Demineralized dentin beams were pretreated with respective crosslinkers for 1 or 5 min. Demineralized dentin beams with no crosslinker pretreatment served as control. The reduction in the total activity of dentin matrices were measured using generic MMP activity assay. Dentin slabs were used for in situ zymography and evaluated by using hydrolysis of self-quenched fluorescein-conjugated gelatin under confocal microscopy. Dentin beam extracts were used for total protein assay and multiplex analysis and powder extracts were used for gelatin zymography. Results. MMP activity in crosslinker pretreated samples decreased significantly between 21% and 70%, whereas untreated control samples' activity increased up to 84%. Zymograms confirmed a decrease in the gelatinolytic activity and in the amount of extractable total protein content. Multiplex analysis of extracts of crosslinker-treated dentin showed a reduction in the MMP-8, MMP-2 and MMP-9 release. Significance. The result of this work suggests that the effect of the crosslinkers is source dependent. The use of crosslinkers for as little as 1 min on demineralized dentin can inactivate the endogenous protease activity of dentin matrices. (C) 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.Peer reviewe

Fungal allergy in asthma-state of the art and research needs

Sensitization to fungi and long term or uncontrolled fungal infection are associated with poor control of asthma, the likelihood of more severe disease and complications such as bronchiectasis and chronic pulmonary aspergillosis. Modelling suggests that >6.5 million people have severe asthma with fungal sensitizations (SAFS), up to 50% of adult asthmatics attending secondary care have fungal sensitization, and an estimated 4.8 million adults have allergic bronchopulmonary aspergillosis (ABPA). There is much uncertainty about which fungi and fungal allergens are relevant to asthma, the natural history of sensitisation to fungi, if there is an exposure response relationship for fungal allergy, and the pathogenesis and frequency of exacerbations and complications. Genetic associations have been described but only weakly linked to phenotypes. The evidence base for most management strategies in ABPA, SAFS and related conditions is weak. Yet straightforward clinical practice guidelines for management are required. The role of environmental monitoring and optimal means of controlling disease to prevent disability and complications are not yet clear. In this paper we set out the key evidence supporting the role of fungal exposure, sensitisation and infection in asthmatics, what is understood about pathogenesis and natural history and identify the numerous areas for research studies

A new type of reconstruction on the InSb() surface determined by grazing incidence X-ray diffraction

The (3×3) reconstruction of the InSb( ) surface has been investigated by grazing incidence X-ray diffraction and scanning tunneling microscopy. The structure is characterized by 6-atom rings on top of a slightly buckled InSb top double layer. Two types of rings have been found, an elliptic ring consisting of 4 In and 2 Sb atoms and a trigonal ring with 3 In and 3 Sb atoms. The bond angles and lengths are consistent with the concept of rehybridization and depolarization which explains the reconstructions of the (111) and (110) surfaces