SE ONE Research Articles

Submarine morphology of Pantelleria volcano: The interplay between volcanic and erosive-depositional processes modulated by sea-level fluctuations.

High-resolution multibeam data integrated with seismic reflection profiles are used to identify and characterize the main primary volcanic and erosive-depositional features along the submarine part (about the 80%) of the active Pantelleria volcano located in the Sicily Channel. Volcanic features include lava flows, cones and elongated ridges. Lava flows are mainly recognized over the insular shelf, while volcanic cones and ridges are mostly concentrated along the steep submarine flanks, especially along the wider SE and NW ones. A strong volcano-tectonic interaction is envisaged for their formation, as indicated by their preferential elongation or alignment along the (main) SE-NW and (secondary) SW-NE directions that have controlled the evolution of the whole volcanic edifice. Erosive-depositional features mainly include small-scale landslide scars and narrow gullies affecting the edge of the insular shelf and overlying submarine depositional terraces. Gullies sometimes merge downslope in larger channels, whose formation is primarily controlled by the distribution of volcanic features and/or shelf sectors characterized by different age or lithologies. Based on the marked morphological differences between the different flanks of the Pantelleria volcano, we infer an overall migration of the volcanic activity from SE to NW over time. This migration is apparently in contrast with the presence of a much wider but shallower NW insular shelf with respect to the SE one. This anomaly can be explained through a two-stage model, with the formation, in the NW sector, of a polygenic shelf rejuvenated by volcanic progradation during the last eustatic hemicycle. The different depths of the insular shelf edge around the island also provide insights on vertical deformations that affected the Pantelleria volcano during the Late-Quaternary.

Study of the amorphous and crystalline states in Ge(Te1-xSex) thick films (x = 0, 0.50) by in situ temperature-dependent structural analyses

As-deposited and unencapsulated GeTe1-xSex (x = 0, 0.5) 3-μm-thick amorphous films on Si(001) were obtained via the thermal co-evaporation technique. The crystallization and the structure of these phase change materials were examined using in situ temperature-dependent X-ray diffraction (XRD) and grazing-incidence fluorescence X-ray Absorption Near Edge Structure (XANES) in isochronal annealing conditions under nitrogen flow. The results show that the onset temperature of crystallization is highly sensitive to the substitution of the Te atoms by the Se ones and that the rhombohedral structure, with the space group R3m, is the one that crystallized for both samples without Ge or Te rejection. Moreover, the local order around the Ge and Se atoms, probed by Ge and Se K-edge XANES analyses, presents clear modifications from the amorphous state to the crystalline one expecting a Ge four-fold and a Se two-fold coordination in the amorphous state, with an increase of the local disorder with the Se substitution (x = 0.5).

Dentin bond strengths of all-in-one adhesives combined with different manufacturers' flowable resin composites.

The present study aimed to evaluate the dentin bond strengths of all-in-one adhesives in combination with flowable-resin-composites of different manufacturers. The materials used in this study were two all-in-one adhesives (BeautiBond Multi, BM, and Clearfil Bond SE ONE, SE) and four flowable resin composites (Clearfil Majesty ES Flow, CME; Estelite Flow Quick, EFQ; MI Flow II, MIF; and Beautifil Flow Plus F03, BFP). By combining each all-in-one adhesive and flowable resin composite, eight experimental groups were established. The shear bond strengths (SBSs) in each group were measured, and the data were statistically analyzed using one-way analysis of variance. The SBSs of the group that used SE showed no significant differences among all flowable resin composites (p>0.05), whereas those of the group that used BM showed significant differences between BFP and CME, and CME and EFQ. The combinations showed dentin bond strength ranging approximately from 20 to 30 MPa.

Exposure to multiple metals/metalloids and human semen quality: A cross-sectional study

BackgroundExposure to metals/metalloids, including essential and nonessential elements, has been associated to male reproductive health in animals. However, findings from human studies are inconsistent. ObjectivesTo investigate the impact of exposure to multiple metals/metalloids at environmental levels on the conventional human semen-quality parameters. Materials and methodsMen living in rural or industrial areas were recruited by personalized letters. No exclusion criteria were applied. Each man provided one semen sample and one blood sample. We analyzed the semen sample both to determine conventional sperm parameters (concentration, progressive motility and normal forms) and to quantify lead (Pb), cadmium (Cd), mercury (Hg), arsenic (As), nickel (Ni), vanadium (V) and selenium (Se) levels. The levels of these metals/metalloids were also quantified in venous blood and spermatozoa samples. Associations between the blood/seminal plasma metal/metalloid levels and semen quality parameters were assessed using confounder adjusted logistic regression models. Correlation and interactions between blood/seminal plasma and semen metal/metalloid levels were investigated using the Spearman’s correlation. ResultsWe found a positive association of seminal plasma cadmium level with lower Total count (OR = 4.48, 95%CI 0.25–80); whereas lead (OR = 4.51, 95%CI 0.86–23) and cadmium (OR = 3.45, 95%CI 0.77–16) seminal plasma levels had a positive association with progressive sperm motility. Overall, these associations remained suggestive after adjustment, though statistically unstable risks. Finally, we found weak interactions between beneficial effects of Se and detrimental ones only for Cd and Pb blood level on sperm concentration, total sperm count and progressive sperm motility. ConclusionsOur findings suggest that environmental exposure to Pb and Cd contributes to a decline in human semen quality, whereas Se can have beneficial effects. Measurements of metals/metalloids in the seminal fluid may be more predictable of semen quality than conventional blood measurements

Antitumor Activity of Selenium and Search Parameters for Its New Potentially Active Derivatives

The trace element selenium is known to manifest antitumor activity. There is a relationship between the development of cancer and selenium content in food. Recent data demonstrated the necessity of increasing selenium consumption for the prevention and treatment of oncological diseases. Certain features of cancer cells and potential targets of selenium therapy are discussed. Both natural forms of selenium, namely, element Se, sodium selenite, L-selenocystine, L-selenomethionine, and L-methylselenocysteine, and synthetic ones, methylseleninic acid and imidoselenocarbamate derivatives, which display antitumor activity due to the generation of methylselenol and hydrogen selenide, the main anticarcinogenic metabolites, are reviewed. New promising anticancer selenium compounds, diacetophenonyl selenide, 2-methylselanyl-1-phenylethanol, and amino acids 2-amino-3-selanyl butanoic acid and 2-amino-3-(methylselanyl) butanoic acid are discussed.

Achieving an Ultrahigh Power Factor in Sb2Te2Se Monolayers via Valence Band Convergence.

An efficient approach to improve the thermoelectric performance of materials is to converge their electronic bands, which is known as band engineering. In this regard, lots of effort has been made to further improve the thermoelectric efficiency of bulk and exfoliated monolayers of Bi2Te3 and Sb2Te3. However, ultrahigh band degeneracy and thus significant improvement of the power factor have not yet been realized in these materials. Using first-principles methods, we demonstrate that the valley degeneracy of Bi2Te3 and Sb2Te3 can be largely improved upon substitution of the middle-layer Te atoms with the more electronegative S or Se atoms. Our detailed analysis reveals that in this family of materials, two out of four possible valence band valleys merely depend on the electronegativity of the middle-layer chalcogen atoms, which makes the independent modulation of the valleys' position feasible. As such, band alignment of Bi2Te3 and Sb2Te3 largely improves upon substitution of the middle-layer Te atoms with more electronegative, yet chemically similar, S and Se ones. A superior valence band alignment is attained in Sb2Te2Se monolayers where three out of four possible valleys are well aligned, resulting in a giant band degeneracy of 18 that holds the record among all thermoelectric materials. As a result, an outstanding power factor for the hole-doped monolayers is achieved, indicating a highly efficient p-type thermoelectric material.

Incorporation of a hydrophilic amide monomer into a one-step self-etch adhesive to increase dentin bond strength: Effect of application time.

The purpose was to evaluate the effect of a hydrophilic amide monomer on μTBS of one-step adhesive to dentin at different application times. Clearfil Universal Bond Quick (UBQ), experimental adhesive (UBQexp; same compositions as UBQ but hydrophilic amide monomer was replaced with 2-hydroxyethyl methacrylate), Clearfil SE ONE and Clearfil SE Bond were applied to midcoronal dentin prepared with 600-grit SiC at different application time (0, 10, 20 and 40 s). Water sorption (Wsp) and the ultimate tensile strength (UTS) of polymerized adhesives were also measured. UBQ showed significantly lower Wsp and higher UTS than UBQexp. At each application time, UBQ exhibited significantly higher μTBSs than UBQexp. UBQ showed the highest μTBS at 0 s application time among all the adhesives. When the application time was prolonged from 0 s to 10 s, only UBQ showed no significant difference. The hydrophilic amide monomer increased μTBS with reduction in Wsp and increase in the UTS and may allow a shortened application time.

Effect of different remaining dentin thickness and long term water storage on dentin bond strength.

The purpose of this study was to investigate the effect of remaining dentin thickness (RDT) and long term water storage on dentin bond strength in-vitro. Twenty-seven third molars were randomly divided into 3 groups: Clearfil Bond SE ONE (SE1, Kuraray Noritake Dental, Okayama, Japan), G-Bond plus (GB, GC, Tokyo, Japan) and Clearfil Mega Bond (MB, Kuraray Noritake Dental). Bonded specimens were stored in water at 37ºC for 24 h. The teeth were then sectioned perpendicular to the adhesive interface to produce beams. RDT of each beam was measured digital calliper. Microtensile bond strength testing was carried out at a crosshead speed of 1 mm/min after 24 h and 1 year water storage. Thicker RDT produced higher bond strengths with one/two-step self-etch materials tested except for the group of 24 h MB. Nevertheless water storage time and RDT affected µTBS in all materials used.

The effect of warm air-blowing on the microtensile bond strength of one-step self-etch adhesives to root canal dentin

PurposeThe use of warm air-blowing to evaporate solvents of one-step self-etch adhesive systems (1-SEAs) has been reported to be a useful method. The purpose of this study was to evaluate the effect of warm air-blowing on root canal dentin. MethodsFour 1-SEAs (Clearfil Bond SE ONE, Unifil Core EM self-etch bond, Estelink, BeautiDualbond EX) were used. Each 1-SEA was applied to root canal dentin according to the manufacturers’ instructions. After the adhesives were applied, solvent was evaporated using either normal air (23±1°C) or warm air (80±1°C) for 20s, and resin composite was placed in the post spaces. The air from the dryer, which could be used in normal- or hot-air-mode, was applied at a distance of 5cm above the root canal cavity in the direction of tooth axis. The temperature of the stream of air from the dryer in the hot-air-mode was 80±1°C, and in the normal mode, 23±1°C. After water storage of the specimens for 24h, the μTBS were evaluated at the coronal and apical regions. The μTBSs were statistically analyzed using three-way ANOVA and Student’s t-test with Bonferroni correction (α=0.05). ResultsThe warm air-blowing significantly increased the μTBS of all 1-SEAs at the apical regions, and also significantly increased the μTBS of two adhesives (Estelink and BeautiDualBond EX) at coronal regions. ConclusionsThe μTBS of 1-SEAs to root canal dentin was improved by using warm air-blowing.

Influence of different etching modes on bond strength and fatigue strength to dentin using universal adhesive systems

ObjectivesThe purpose of this study was to determine the dentin bonding ability of three new universal adhesive systems under different etching modes using fatigue testing. MethodPrime & Bond elect [PE] (DENTSPLY Caulk), Scotchbond Universal [SU] (3M ESPE), and All Bond Universal [AU] (Bisco) were used in this study. A conventional single-step self-etch adhesive, Clearfil Bond SE ONE [CS] (Kuraray Noritake Dental) was also included as a control. Shear bond strengths (SBS) and shear fatigue strength (SFS) to human dentin were obtained in the total-etch mode and self-etch modes. For each test condition, 15 specimens were prepared for the SBS and 30 specimens for SFS. SEM was used to examine representative de-bonded specimens, treated dentin surfaces and the resin/dentin interface for each test condition. ResultsAmong the universal adhesives, PE in total-etch mode showed significantly higher SBS and SFS values than in self-etch mode. SU and AU did not show any significant difference in SBS and SFS between the total-etch mode and self-etch mode. However, the single-step self-etch adhesive CS showed significantly lower SBS and SFS values in the etch-and-rinse mode when compared to the self-etch mode. Examining the ratio of SFS/SBS, for PE and AU, the etch-and-rinse mode groups showed higher ratios than the self-etch mode groups. SignificanceThe influence of different etching modes on dentin bond quality of universal adhesives was dependent on the adhesive material. However, for the universal adhesives, using the total-etch mode did not have a negative impact on dentin bond quality.

Effect of a functional monomer (MDP) on the enamel bond durability of single-step self-etch adhesives.

The present study aimed to determine the effect of the functional monomer, 10-methacryloxydecyl dihydrogen phosphate (MDP), on the enamel bond durability of single-step self-etch adhesives through integrating fatigue testing and long-term water storage. An MDP-containing self-etch adhesive, Clearfil Bond SE ONE (SE), and an experimental adhesive, MDP-free (MF), which comprised the same ingredients as SE apart from MDP, were used. Shear bond strength (SBS) and shear fatigue strength (SFS) were measured with or without phosphoric acid pre-etching. The specimens were stored in distilled water for 24 h, 6 months, or 1 yr. Although similar SBS and SFS values were obtained for SE with pre-etching and for MF after 24 h of storage in distilled water, SE with pre-etching showed higher SBS and SFS values than MF after storage in water for 6 months or 1 yr. Regardless of the pre-etching procedure, SE showed higher SBS and SFS values after 6 months of storage in distilled water than after 24 h or 1 yr. To conclude, MDP might play an important role in enhancing not only bond strength but also bond durability with respect to repeated subcritical loading after long-term water storage.

Nanoleakage in Hybrid Layer and Acid-Base Resistant Zone at the Adhesive/Dentin Interface.

The aim of interfacial nanoleakage evaluation is to gain a better understanding of degradation of the adhesive-dentin interface. The acid-base resistant zone (ABRZ) is recognized at the bonded interface under the hybrid layer (HL) in self-etch adhesive systems after an acid-base challenge. The purpose of this study was to evaluate nanoleakage in HL and ABRZ using three self-etch adhesives; Clearfil SE Bond (SEB), Clearfil SE One (SEO), and G-Bond Plus (GBP). One of the three adhesives was applied on the ground dentin surface and light cured. The specimens were longitudinally divided into two halves. One half remained as the control group. The others were immersed in ammoniacal silver nitrate solution, followed by photo developing solution under fluorescent light. Following this, the specimens were subjected to acid-base challenges with an artificial demineralization solution (pH4.5) and sodium hypochlorite, and prepared in accordance with common procedures for transmission electron microscopy (TEM) examination. The TEM images revealed silver depositions in HL and ABRZ due to nanoleakage in all the adhesives; however, the extent of nanoleakage was material dependent. Funnel-shaped erosion beneath the ABRZ was observed only in the all-in-one adhesive systems; SEO and GBP, but not in the two-step self-etch adhesive system; SEB.

Nondestructive observation of teeth post core space using optical coherence tomography: a pilot study

Coronal tooth lesions, such as caries, enamel cracking, and composite resin restoration cavities, have been observed by optical coherence tomography (OCT). This pilot study was performed to verify whether OCT could reveal details of root canals filled with resin core build-up. A dual-cure, one-step, self-etch adhesive system-bonding agent (Clearfil Bond SE ONE, Kuraray Noritake Dental) and dual-cure resin composite core material (Clearfil DC Core Automix ONE, Kuraray Noritake Dental) were used according to the manufacturer's instructions in root canals. OCT was performed at three stages of the core build-up: after the post space preparation, after bonding application, and after resin core fabrication. The cementum was removed in the cementum absent group and the root was left untreated in the cementum present group. Bubbles were observed in the resin cores and gaps formed between the resin core and dentin. In the cementum absent group, the internal structure of the root could be visualized clearly compared with the cementum present group. The root internal structure could be observed by OCT and the image became clearer when cementum was removed.

Fatigue crack growth rates and paths in two planar specimens under mixed mode loading

This paper focuses on the evaluation of methods for estimating fatigue crack growth (FCG) under mixed mode I/II loading. The experimental part of the study consists of a series of fatigue crack growth tests on bend and tension specimens with geometries similar to the standard SE(B) and SE(T) ones. For the above specimen types, both Mode I and mixed mode FCG tests are first performed. To facilitate an accurate evaluation of the test results, finite element analyses of stress intensity factors for crack geometries following the experimentally measured crack trajectories are carried out. Additionally, the XFEM based algorithm available in the finite element code ABAQUS is explored with respect to its performance in estimating crack growth paths.The subsequent test evaluation focuses on examining a correlation between FCG rates for mixed mode loading conditions with the Mode I baseline curve. The results suggest that, using Mode I experimental data, both conservative and non-conservative estimation of mixed mode fatigue crack growth is possible. In this context, recommendations of failure assessment procedures regarding the flaw re-characterisation and projection onto principal stress planes, as well as rules for the transferability of Mode I FCG curves to mixed mode conditions, are discussed.

O CLIMA DE ONDAS NA COSTA SUL DE ARRAIAL DO CABO, RJ: DISTRIBUIÇÃO DE PARÂMETROS DE ONDA

A Marinha do Brasil operou um um ondógrafo direcional WAVERIDER DATAWELL ao largo da costa sul de Arraial do Cabo, RJ, sobre uma lâmina d’água de 82 metros, entre agosto de 1988 e outubro de 1999. Os resultados do processamento preliminar das informações de onda direcional são apresentados. As séries temporais de curto termo foram consistidas e então submetidas a rotinas de cálculo do espectro direcional. As séries de parâmetros amostrais como altura significativa, período de pico, direção e espalhamento no período de pico foram sintetizadas na forma de histogramas e diagramas de ocorrência conjunta. Os resultados mostraram que a maior parte da energia provêm de ondas vindas de SSE a SSO, com períodos variando entre 11 e 13 segundos. Um segundo pico de energia vem de ESE a SSE com períodos predominando entre 7 e 9 segundos. O espalhamento das ondas vindas de S, geradas mais distante, foi ligeiramente maior do que as de SE. Isto pode estar relacionado com uma maior variabilidade espaço-temporal dos ventos nas respectivas zonas de geração.

Synthesis of ZnxCd1−xSe (0 ≤x≤ 1) alloyed nanowires for variable-wavelength photodetectors

Variable-wavelength photodetectors are fabricated by a selective growth of ZnxCd1−xSe alloy nanowires on patterned Au catalysts thus forming nanowire air-bridges between two Pt pillar electrodes. From the composition-dependent linear changes of bandgap energies and lattice parameters, ZnxCd1−xSe nanowires are found to be perfectly alloyed in the entire range of Zn composition without any phase separation and have a structural transition from zinc blende to wurtzite at 0.31 < x < 0.72. The spectral responses of ZnxCd1−xSe detectors show that the cut-off wavelength can be continuously tuned within the visible spectrum of light extending from red to blue. In on-off switching operations, all of the detectors can be reversibly switched between the low and the high conductivity state but the CdSe detector has slower response and recovery behaviors than ZnSe and Zn0.72Cd0.28Se ones, which is explained by adsorption and photodesorption of O2 on the surface of CdSe nanowires.

Vibrational, optical and structural studies of an amorphousSe0.90S0.10 alloy produced by mechanical alloying

The local atomic order of an amorphousSe0.90S0.10 alloy produced by mechanical alloying was studied by x-ray diffraction and extendedx-ray absorption fine structure (EXAFS) data obtained at three temperatures,T = 300, 200 and 30 K. From the cumulant analysis of the EXAFS data, structural properties suchas average interatomic distances, average coordination numbers, Debye–Waller factors andanharmonicity, given by the third cumulant, were obtained. The results found indicate thatthere is alloying at an atomic level, and Se–S pairs are more disordered and distorted thanSe–Se ones due to the milling process.

Nonlinear optical properties of Zn 1− xMg xSe and Cd 1− xMg xSe crystals

Nonlinear optical properties of Zn 1− x Mg x Se and Cd 1− x Mg x Se crystals have been studied using degenerate four wave mixing (DFWM), nonlinear transmission (NLT), second harmonic generation (SHG) and third harmonic generation (THG) methods by Nd:YAG laser operating at 532 nm and 1064 nm, respectively. The studied Zn 1− x Mg x Se and Cd 1− x Mg x Se crystals were grown from the melt by the modified high-pressure Bridgman method. The quadratic nonlinear optical properties of ternary crystals were investigated by second harmonic generation (SHG) technique. We found that the highest value of the second order nonlinear optical susceptibility was obtained for Cd 0.7Mg 0.3Se. In the case of cubic nonlinear optical properties we used third harmonic generation (THG) and degenerate four wave mixing (DFWM) methods. We found that the values of third order nonlinear optical susceptibility for Cd 1− x Mg x Se crystals are higher than for Zn 1− x Mg x Se ones.

Magnetic interactions in Cr spinels

Exchange coupling constants J n are estimated for ACr 2 X 4 ( A = Zn , Cd ; X = O , S, Se) spinels by mapping the energy of spin spirals calculated within the LSDA + U approximation onto an effective Heisenberg model. The calculations reproduce the change of the sign of the exchange coupling between Cr nearest neighbors (NN) from AFM in the O spinels to FM in S and Se ones. The exchange interaction between more distant Cr neighbors becomes stronger with the increase of the X atomic number ( Z X ).

Photoemission studies of AsxSe100−x (x:0, 50, 100) films prepared by pulsed-laser deposition—the effect of annealing

Annealing-induced structural changes in amorphous filmsAsxSe100−x (x: 0, 50, 100) prepared by pulsed laser deposition (PLD) on Si substrates werestudied by x-ray and ultraviolet photoelectron spectroscopies (XPS, UPS). Forx = 50, the analysis of the XPS As 3d peak revealed three distinct local environments in which theAs atoms participate in the as-prepared films. The combination of photoemission and workfunction measurements showed that annealing close to the glass transition temperatureinduces atomic rearrangements towards the formation of a more homogenous surfacecomposition as well as to a more energetically favoured film structure, by cleavage of theweaker As–As and Se–Se bonds towards the formation of As–Se ones analogously to As–Ssystem films.