Search results for "diamond."
showing 10 items of 232 documents
Cutting efficency of a new diamond bur for tooth preparation
2003
Objectives: The aim of this study is to compare the cutting efficiency of a recently introduced diamond bur (314.S-6878.016, Komet Brasseler) for tooth preparation with its conventional variant (314.6878.016). Both burs have the same diameter, profile and diamond grains (160µm), but the 6878 have a polygonal section at the cutting portion level; this is claimed to have a percussion effect which can improve the hard tissue removal. Materials and methods: four burs from each type have been selected. Tablets made of human tooth fragments embedded in epoxy resin (4 to 1 w/w ratio) were used as test specimens. Their abrasion resistance is about 14% higher than that of the dentin. The burs were m…
Aggregation properties of proteins under high pressure
2010
Fourier transform infrared spectroscopy (FTIR) coupled with High Pressure (HP) techniques is a suitable tool to investigate unfolding/misfolding processes providing useful information on the kinetics of aggregation of proteins[1]. Since HP affects only the volume contribution to the Gibbs free energy, it is able to perturb the structure of proteins in a reversible way [2][3]. The principle governing pressure effects is that it tends to shift a system towards the state that occupies the smallest volume, it causes the electrostriction of charged and polar groups, the elimination of packing defects, and the solvation of hydrophobic groups. Cavities and packing defects are expected to be major …
In situ micro-Raman and X-ray diffraction study of diamonds and petrology of the new ureilite UAE 001 from the United Arab Emirates
2008
International audience; A new olivine-pigeonite ureilite containing abundant diamonds and graphite was found in the United Arab Emirates. This is the first report of a meteorite in this country. The sample is heavily altered, of medium shock level, and has a total weight of 155 g. Bulk rock, olivine (Fo79.8-81.8) and pyroxene (En73.9-75.2, Fs15.5-16.9, Wo8.8-9.5) compositions are typical of ureilites. Olivine rims are reduced with Fo increasing up to Fo96.1-96.8. Metal in these rims is completely altered to Fehydroxide during terrestrial weathering. We studied diamond and graphite using micro-Raman and in situ synchrotron X-ray diffraction. The main diamond Raman band (LO=TO mode at ~1332 c…
FTIR analysis of the high pressure response of native insulin assemblies
2013
It is widely recognized that a central role in conferring stability to the structure of proteins against misfolding and aggregation is played by the formation of oligomers. The case of insulin is prototypical in this respect: in our body it is stored up in stable inactive hexameric assemblies whereas only in its monomeric form it recovers the role of regulating carbohydrate and fat metabolism. In the present paper, exploiting the optimal coupling between FTIR spectroscopy and diamond anvil cell technique, we probe the stability of different insulin oligomeric forms under high pressure, namely over the ranges 0-15 kbar for water solution and 0-80 kbar for dry powder. Results obtained show di…
Tribological properties of thin films made by atomic layer deposition sliding against silicon
2018
Interfacial phenomena, such as adhesion, friction, and wear, can dominate the performance and reliability of microelectromechanical (MEMS) devices. Here, thin films made by atomic layer deposition (ALD) were tested for their tribological properties. Tribological tests were carried out with silicon counterpart sliding against ALD thin films in order to simulate the contacts occurring in the MEMS devices. The counterpart was sliding in a linear reciprocating motion against the ALD films with the total sliding distances of 5 and 20 m. Al2O3 and TiO2 coatings with different deposition temperatures were investigated in addition to Al2O3-TiO2-nanolaminate, TiN, NbN, TiAlCN, a-C:H [diamondlike car…
The relation between human values and perceived situation characteristics in everyday life
2018
Values refer to abstract beliefs which serve as guidelines in peoples’ life and affect the way people and events are evaluated. Simultaneously, unlike attitudes, values transcend specific actions, and situations. While recent research showed that values are related to the attention and interpretation of situational information in standardized laboratory settings, up to date hardly any empirical work investigated how values relate to situation perception in daily life. In our study, we assessed the relation between the endorsement of human values and situation characteristics (i.e., the 8 DIAMONDS). Using the Day Reconstruction Method in two samples (German and US-American), we found that es…
Impingement of the Sciatic Nerve due to a Protruding Acetabular Cage Rim
2020
Abstract Sciatic nerve damage is a well-known complication that occurs in 1.5% of patients after primary total hip arthroplasty and in 8% after revision total hip arthroplasty. Yet when considering re-revision arthroplasty and acetabular cage implantation, incidence and management remain unclear. This case report describes a young female patient with sciatic nerve impingement after acetabular cage implantation. Her primary complaint was shooting sciatic left leg pain, worsening on ambulation and when seated. A complete workup was negative for spinal impingement or infection, and axonal nerve damage was confirmed through nerve conduction studies. The intraoperative findings showed that it wa…
Novel Translational Read-through–Inducing Drugs as a Therapeutic Option for Shwachman-Diamond Syndrome
2022
Shwachman-Diamond syndrome (SDS) is one of the most commonly inherited bone marrow failure syndromes (IBMFS). In SDS, bone marrow is hypocellular, with marked neutropenia. Moreover, SDS patients have a high risk of developing myelodysplastic syndrome (MDS), which in turn increases the risk of acute myeloid leukemia (AML) from an early age. Most SDS patients are heterozygous for the c.183-184TA>CT (K62X) SBDS nonsense mutation. Fortunately, a plethora of translational read-through inducing drugs (TRIDs) have been developed and tested for several rare inherited diseases due to nonsense mutations so far. The authors previously demonstrated that ataluren (PTC124) can restore full-length SBDS…
On the high-pressure phase stability and elastic properties ofβ-titanium alloys
2017
We have studied the compressibility and stability of different β-titanium alloys at high pressure, including binary Ti–Mo, Ti–24Nb–4Zr–8Sn (Ti2448) and Ti–36Nb–2Ta–0.3O (gum metal). We observed stability of the β phase in these alloys to 40 GPa, well into the ω phase region in the P–T diagram of pure titanium. Gum metal was pressurised above 70 GPa and forms a phase with a crystal structure similar to the η phase of pure Ti. The bulk moduli determined for the different alloys range from 97 ± 3 GPa (Ti2448) to 124 ± 6 GPa (Ti–16.8Mo–0.13O).
Defying Stereotypes with Nanodiamonds: Stable Primary Diamondoid Phosphines
2016
International audience; Direct unequal C-H bond difunctionalization of phosphorylated diamantane was achieved in high yield from the corresponding phosphonates. Reduction of the functionalized phosphonates provides access to novel primary and secondary alkyl/aryl diamantane phosphines. The prepared primary diamantyl phosphines are quite air stable compared to their adamantyl and especially alkyl or aryl analogues. This finding is corroborated by comparing the singly occupied molecular orbital energy levels of the corresponding phosphine radical cations obtained by density functional theory computations.