Three-dimensional morphometric study on the retromolar pad.

PURPOSE: The aim of this study was to classify the shapes of retromolar pads and assess their morphometric differences using a 3D model. MATERIALS AND METHODS: Two hundred fully edentulous or Kennedy Class I partially edentulous patients (400 retromolar pads) were enrolled. Scan data of the definitive mandibular casts produced through functional impressions were obtained using a 3D laser scanner. Seven parameters (transverse diameter, longitudinal diameter, transverse-contour length, longitudinal-contour length, longitudinal/transverse diameter ratio, longitudinal/transverse-contour length ratio, and angle of the retromolar pad line to the residual alveolar ridge line) were measured using image analysis software. Subsequently, the pads were classified according to the shape. Statistical analyses were performed using 95% confidence intervals. RESULTS: Classifying the retromolar pads into three shapes led to high intra-examiner reliability (Cronbach's alpha = 0.933). The pear shape was the most common (56.5%), followed by oval/round (27.7%) and triangular (15.8%) shapes. There were no significant differences between the left and right sides according to the shape and no significant differences in any parameter according to age. The transverse diameter and longitudinal/transverse diameter ratio differed between sexes (P < .05). The triangular shape had a significantly different transverse diameter, transverse-contour length, longitudinal/transverse diameter ratio, and longitudinal/transverse-contour length ratio compared with the pear and oval/round shapes (P < .05). CONCLUSION: From a clinical reliability standpoint, classifying retromolar pads into three shapes (oval/round, pear-shaped, and triangular) is effective. The differences in the sizes among the shapes were attributed to the transverse measurement values.

Health effects of PM2.5 constituents and source contributions in major metropolitan cities, South Korea.

Ambient PM2.5 is one of the major risk factors for human health, and is not fully explained solely by mass concentration. We examined the short-term associations of cause-specific mortality (i.e., all-cause, cardiovascular, and respiratory mortality) with the 15 chemical constituents and sources of PM2.5 in four metropolitan cities of South Korea during 2014-2018. We found transition metals consistently showed significant associations with all-cause mortality, while the effects of other constituents varied across the cities and for cause of death. Carbonaceous components strongly affected the all-cause, cardiovascular, and respiratory mortality in Daejeon. Secondary inorganic aerosols, SO42- and NH4+, showed significant associations with respiratory mortality in Gwangju. We also found the sources from which species closely linked to mortality generally increased the relative mortality risks. Heavy metal markers from soil or industrial sources were significantly associated with mortality in all cities. However, several sources influenced mortality despite their marker species not being significantly associated with it. Secondary nitrate and secondary sulfate sources were linked to mortality in DJ. This could be attributed to the deep inland location, which might have facilitated formation of secondary inorganic aerosols. In addition, primary sources including mobile and coal combustion seemed to have acute impacts on respiratory mortality in Gwangju. Our findings suggest the necessity of positive matrix factorization (PMF)-based approaches for evaluating health effects of PM2.5 while considering the spatial heterogeneity in the compositions and source contributions of PM2.5.

Two-point coupling method to independently control coupling efficiency at different wavelengths.

To efficiently access light waves confined in a high-quality-factor (Q) microcavity over a wide spectral range, it is necessary to independently control coupling efficiency at different wavelengths. Here we suggest an approach to add a degree of freedom to control the coupling efficiency based on a two-point coupling geometry. By changing the phase difference between two paths connecting two coupling points, various combinations of coupling efficiencies at multiple wavelengths can be achieved. An analytic model describing the coupling property is derived and confirmed by experimental results. It is also shown that the coupling property can be modified by adjusting the effective refractive index difference between a waveguide and a resonator.

Supercontinuum generation in As2S3 waveguides fabricated without direct etching.

We report a supercontinuum generation (SCG) in a waveguide that spontaneously forms without an etching process during the deposition of a core material on a preformed ${\rm{Si}}{{\rm{O}}_2}$ substructure. The mechanism of dispersion control for this new, to the best of our knowledge, type of waveguide is analyzed by numerical simulation, which results in a design rule to achieve a target dispersion profile by adjusting the substructure geometry. SCG is experimentally demonstrated with a waveguide made of ${\rm{A}}{{\rm{s}}_2}{{\rm{S}}_3}$, chalcogenide glass, which has low material absorption over the mid-IR range. A dispersion-controlled waveguide with a length of 10 mm pumped with 77 pJ pulses at a telecommunication wavelength of 1560 nm resulted in a supercontinuum that extends by more than 1.5 octaves.

Hydrophobic passivation of ultra-high-Q silica wedge resonators using hexamethyldisilazane.

Dissipative Kerr solitons in ultra-high-Q resonators are extremely sensitive to the thermal behavior of the resonators. Especially for resonators with hydrophilic surfaces, moisture continuously adsorbs on their surfaces and causes additional absorption loss that results in an excessive thermal shift of resonance frequency. This change makes soliton mode locking more challenging or even impossible. Here, we report hydrophobic monolayer passivation using hexamethyldisilazane on ultra-high-Q silica wedge resonators. It was experimentally confirmed that the Q-factor and dispersion were maintained after passivation, and excess thermal shift by moisture was inhibited for more than three days in the atmosphere. Soliton mode locking was successfully performed with the resonator one month after passivation.

Universal light-guiding geometry for on-chip resonators having extremely high Q-factor.

By providing an effective way to leverage nonlinear phenomena in integrated devices, high-Q optical resonators have led to recent advances in on-chip photonics. However, developing fabrication processes to shape any new material into a resonator with extremely smooth surfaces on a chip has been an exceptionally challenging task. Here, we describe a universal method to implement ultra-high-Q resonators with any new material having desirable properties that can be deposited by physical vapor deposition. Using this method light-guiding cores with surface roughness on the molecular-scale are created automatically on pre-patterned substrates. Its efficacy has been verified using As2S3, a chalcogenide glass that has high-nonlinearity. The Q-factor of the As2S3 resonator so-developed approached the propagation loss record achieved in chalcogenide fibers which were limited by material losses. Owing to the boosted Q-factor, lasing by stimulated Brillouin scattering has been demonstrated with 100 times lower threshold power than the previous record.

Effect of emergency medical service use on time interval from symptom onset to hospital admission for definitive care among patients with intracerebral hemorrhage: a multicenter observational study.

OBJECTIVE: This study evaluated whether emergency medical service (EMS) use was associated with early arrival and admission for definitive care among intracerebral hemorrhage (ICH) patients. METHODS: Patients with ICH were enrolled from 29 hospitals between November 2007 and December 2012, excluding those patients with subarachnoid hemorrhage, traumatic ICH, and missing information. The patients were divided into four groups based on visit type to the definitive hospital emergency department (ED): direct visit by EMS (EMS-direct), direct visit without EMS (non-EMS-direct), transferred from a primary hospital by EMS (EMS-transfer), and transferred from a primary hospital without EMS (non-EMS-transfer). The outcomes were the proportions of participants within early (<1 hr) definitive hospital ED arrival from symptom onset (pS2ED) and those within early (<4 hr) admission from symptom onset (pS2AD). Adjusted odds ratios were calculated to determine the association between EMS use and outcomes with and without inter-hospital transfer. RESULTS: A total of 6,564 patients were enrolled. The adjusted odds ratios (95% confidence intervals) for pS2ED were 22.95 (17.73-29.72), 1.11 (0.67-1.84), and 7.95 (6.04-10.46) and those for pS2AD were 5.56 (4.70-6.56), 0.96 (0.71-1.30), and 2.35 (1.94-2.84) for the EMS-direct, EMS-transfer, and non-EMS-direct groups compared with the non-EMS-transfer group, respectively. Through the interaction model, EMS use was significantly associated with early arrival and admission among direct visiting patients but not with transferred patients. CONCLUSION: EMS use was significantly associated with shorter time intervals from symptom onset to arrival and admission at a definitive care hospital. However, the effect disappeared when patients were transferred from a primary hospital.

High quality chalcogenide-silica hybrid wedge resonator.

Chalcogenide glasses, with high nonlinearity and low loss, have captured research interest as an integrated device platform for near- and mid-infrared nonlinear optical devices. Compared to silicon-based microfabrication technologies, chalcogenide fabrication processes are less mature and a major challenge is obtaining high quality devices. In this paper, we report a hybrid resonator design leveraging a high quality silica resonator to achieve high Q factors with chalcogenide. The device is composed of a thin chalcogenide layer deposited on a silica wedge resonator. The hybrid resonators exhibit loaded Q factors up to 1.5 x 105 in the near-infrared region. We also measured the effective thermo-optic coefficient of the device to be 5.5x10-5/K, which agreed well with the bulk value. Thermal drift of the device can be significantly reduced by introducing a titanium dioxide cladding layer with a negative thermo-optic coefficient.

Simple method for high-performance stretchable composite conductors with entrapped air bubbles.

We integrate air bubbles into conductive elastic composite-based stretchable conductors to make them mechanically less stiff and electrically more robust against physical deformations. A surfactant facilitates both the formation and maintenance of air bubbles inside the elastic composites, leading to a simple fabrication of bubble-entrapped stretchable conductors. Based on the unique bubble-entrapped architecture, the elastic properties are greatly enhanced and the resistance change in response to tensile strains can clearly be controlled. The bubble-entrapped conductor achieves ~80 % elongation at ~3.4 times lower stress and ~44.8 % smaller change in the electrical resistance at 80 % tensile strain, compared to bare conductor without air bubbles.

Axial displacements in external and internal implant-abutment connection.

OBJECTIVES: The purpose of this study was to evaluate the axial displacement of the abutments during clinical procedures by the tightening torque and cyclic loading. MATERIALS AND METHODS: Two different implant-abutment connection systems were used (external butt joint connection [EXT]; internal tapered conical connection [INT]). The master casts with two implant replicas, angulated 10° from each other, were fabricated for each implant connection system. Four types of impression copings were assembled and tightened with the corresponding implants (hex transfer impression coping, non-hex transfer impression coping, hex pick-up impression coping, non-hex pick-up impression coping). Resin splinted abutments and final prosthesis were assembled. The axial displacement was measured from the length of each assembly, which was evaluated repeatedly, after 30 Ncm torque tightening. After 250 N cyclic loading of final prosthesis for 1,000,000 cycles, additional axial displacement was recorded. The mean axial displacement was statistically analyzed (repeated measured ANOVA). RESULTS: There was more axial displacement in the INT group than that of the EXT group in impression copings, resin splinted abutments, and final prosthesis. Less axial displacement was found at 1-piece non-hex transfer type impression coping than other type of impression copings in the INT group. There was more axial displacement at the final prosthesis than resin splinted abutments in the INT and the EXT groups. After 250 N cyclic loading of final prosthesis, the INT group showed more axial displacement than that of the EXT group. CONCLUSION: Internal tapered conical connection demonstrated a varying amount of axial displacement with tightening torque and cyclic loading.

Minimally invasive treatment for esthetic enhancement of white spot lesion in adjacent tooth.

This article describes the treatment provided to a patient with the maxillary anterior teeth exhibiting severe secondary caries beneath the previous restoration and a white spot lesion on the adjacent incisor. Two implants were placed after extraction of hopeless teeth with the guided bone regeneration technique. A white spot lesion of the adjacent incisor was treated with minimally invasive treatment. This clinical report describes the multidisciplinary treatment for the white spot lesion and esthetic restoration of missing anterior teeth.

High-performance, transparent, and stretchable electrodes using graphene-metal nanowire hybrid structures.

Transparent electrodes that can remain electrically conductive and stable under large mechanical deformations are highly desirable for applications in flexible and wearable electronics. This paper describes a comprehensive study of the electrical, optical, and mechanical properties of hybrid nanostructures based on two-dimensional graphene and networks of one-dimensional metal nanowires, and their use as transparent and stretchable electrodes. Low sheet resistance (33 Ω/sq) with high transmittance (94% in visible range), robust stability against electric breakdown and oxidation, and superb flexibility (27% in bending strain) and stretchability (100% in tensile strain) are observed, and these multiple functionalities of the hybrid structures suggest a future promise for next generation electronics. The use of hybrid electrodes to fabricate oxide semiconductor transistors and single-pixel displays integrated on wearable soft contact lenses with in vivo tests are demonstrated.

Stretchable, transparent graphene interconnects for arrays of microscale inorganic light emitting diodes on rubber substrates.

This paper describes the fabrication and design principles for using transparent graphene interconnects in stretchable arrays of microscale inorganic light emitting diodes (LEDs) on rubber substrates. We demonstrate several appealing properties of graphene for this purpose, including its ability to spontaneously conform to significant surface topography, in a manner that yields effective contacts even to deep, recessed device regions. Mechanics modeling reveals the fundamental aspects of this process, as well as the use of the same layers of graphene for interconnects designed to accommodate strains of 100% or more, in a completely reversible fashion. These attributes are compatible with conventional thin film processing and can yield high-performance devices in transparent layouts. Graphene interconnects possess attractive features for both existing and emerging applications of LEDs in information display, biomedical systems, and other environments.

Waterproof AlInGaP optoelectronics on stretchable substrates with applications in biomedicine and robotics.

Inorganic light-emitting diodes and photodetectors represent important, established technologies for solid-state lighting, digital imaging and many other applications. Eliminating mechanical and geometrical design constraints imposed by the supporting semiconductor wafers can enable alternative uses in areas such as biomedicine and robotics. Here we describe systems that consist of arrays of interconnected, ultrathin inorganic light-emitting diodes and photodetectors configured in mechanically optimized layouts on unusual substrates. Light-emitting sutures, implantable sheets and illuminated plasmonic crystals that are compatible with complete immersion in biofluids illustrate the suitability of these technologies for use in biomedicine. Waterproof optical-proximity-sensor tapes capable of conformal integration on curved surfaces of gloves and thin, refractive-index monitors wrapped on tubing for intravenous delivery systems demonstrate possibilities in robotics and clinical medicine. These and related systems may create important, unconventional opportunities for optoelectronic devices.

Bone response of Mg ion-implanted clinical implants with the plasma source ion implantation method.

OBJECTIVES: This study examined the bone response of magnesium (Mg) ion-implanted implants produced using a plasma source ion implantation method. MATERIALS AND METHODS: The surface characteristics were evaluated by scanning electron microscopy, Auger electron spectroscopy, X-ray photoelectron spectroscopy, and Rutherford backscattering spectroscopy. The screw-type titanium implants were treated with resorbable blasting media (RBM) and divided into one control group (RBM implants) and three test groups (Mg ion-implanted implants with different retained Mg doses). Twenty-four implants from each group were placed into the tibiae of 24 New Zealand white rabbits. After allowing 6 weeks for healing, the removal torque (RTQ) was measured and the implants were subjected to histomorphometric analysis. RESULTS: The surface roughness and surface morphology of the test groups were similar. The Mg ion-implanted implants with a 2.3 x 10(15) ions/cm(2) retained dose showed a significantly higher RTQ than the other implants. Histomorphometric analysis indicated that the bone contact of this group was superior to the other groups. CONCLUSION: The bone response of Mg ion-implanted implant showed results superior or similar to an RBM-treated implant. The optimal Mg ion concentration that induced the strongest osseointegration was approximately 9%.

Full mouth fixed implant rehabilitation in a patient with generalized aggressive periodontitis.

BACKGROUND: Generalized aggressive periodontitis (GAP) is a destructive periodontal disease that can develop in young age. Only a few cases of full mouth rehabilitation, using dental implants, have been reported in a patient with aggressive periodontitis. CASE DESCRIPTION: This clinical report describes the treatment procedures and results of full mouth rehabilitation in a patient with aggressive periodontitis. After all teeth were extracted, 6 implants were placed in the maxilla and mandible, respectively. Fixed detachable implant prostheses were made. The patient was satisfied with the final results. She was followed for 10 months postloading. CLINICAL IMPLICATION: For a long-term success, continuous maintenance care is critical, as the contributing factors of the disease (such as immune factors or periodontal pathogens) may not be controlled adequately.

Histomorphometry and stability analysis of early loaded implants with two different surface conditions in beagle dogs.

STATEMENT OF PROBLEM: Despite an improved bone reactions of Mg-incorporated implants in the animals, little yet has been carried out by the experimental investigations in functional loading conditions. PURPOSE: This study investigated the clinical and histologic parameters of osseointegrated Mg-incorporated implants in early loading conditions. MATERIAL AND METHODS: A total of 36 solid screw implants (diameter 3.75 mm, length 10 mm) were placed in the mandibles of 6 beagle dogs. Test groups included 18 Mg-incorporated implants. Turned titanium implants served as control. Gold crowns were inserted 4 weeks after implant placement and the dogs were immediately put on a food diet. Implants were observed for 10 weeks after loading. Radiographic assessments and stability tests were performed at the time of fixture installation, 2(nd) stage surgery, 4 weeks after loading, and 10 weeks after loading. Histological observations and morphometrical measurements were also performed. RESULTS: Of 36 implants, 33 displayed no discernible mobility, corresponding to successful clinical function. There was no statistically significant difference between test implants and controls in marginal bone levels (P = .46) and RFA values. The mean BIC% in the Mg-implants was 54.5 ± 8.4%. The mean BIC% in the turned implant was 45.3 ± 12.2%. These differences between the Mg-implant and control implant were statistically significant (P = .005). CONCLUSIONS: The anodized, Mg-incorporated implant demonstrated significantly more bone-to-implant contact (BIC) in early loading conditions. CLINICAL IMPLICATIONS: The results of this study in beagle dogs suggest the possibility of achieving predictable stability of early loaded free-standing dental implants with Mg-incorporated surface.

Human hepatitis B virus-X protein alters mitochondrial function and physiology in human liver cells.

The hepatitis B virus-X protein (HBx) regulates fundamental aspects of mitochondrial physiology. We show that HBx down-regulates mitochondrial enzymes involved in electron transport in oxidative phosphorylation (complexes I, III, IV, and V) and sensitizes the mitochondrial membrane potential in a hepatoma cell line. HBx also increases the level of mitochondrial reactive oxygen species and lipid peroxide production. HBx does not activate apoptotic signaling, although it sensitizes hepatoma cells to apoptotic signaling, which is dependent on reactive oxygen species. Increased intrahepatic lipid peroxidation in HBx transgenic mice demonstrated that oxidative injury occurs as a direct result of HBx expression. Therefore, we conclude that mitochondrial dysfunction is a crucial pathophysiological factor in HBx-expressing hepatoma cells and provides an experimental rationale in the investigation of mitochondrial function in rapidly renewed tissues, as in hepatocellular carcinomas.

Molecular mechanisms of curcumin-induced cytotoxicity: induction of apoptosis through generation of reactive oxygen species, down-regulation of Bcl-XL and IAP, the release of cytochrome c and inhibition of Akt.

Curcumin, a natural, biologically active compound extracted from rhizomes of Curcuma species, has been shown to possess potent anti-inflammatory, anti-tumor and anti-oxidative properties. The mechanism by which curcumin initiates apoptosis remains poorly understood. In the present report we investigated the effect of curcumin on the activation of the apoptotic pathway in human renal Caki cells. Treatment of Caki cells with 50 microM curcumin resulted in the activation of caspase 3, cleavage of phospholipase C-gamma1 and DNA fragmentation. Curcumin-induced apoptosis is mediated through the activation of caspase, which is specifically inhibited by the caspase inhibitor, benzyloxycarbony-Val-Ala-Asp-fluoromethyl ketone. Curcumin causes dose-dependent apoptosis and DNA fragmentation of Caki cells, which is preceded by the sequential dephosphorylation of Akt, down-regulation of the anti-apoptotic Bcl-2, Bcl-XL and IAP proteins, release of cytochrome c and activation of caspase 3. Cyclosporin A, as well as caspase inhibitor, specifically inhibit curcumin-induced apoptosis in Caki cells. Pre-treatment with N-acetyl-cysteine, markedly prevented dephosphorylation of Akt, and cytochrome c release, and cell death, suggesting a role for reactive oxygen species in this process. The data indicate that curcumin can cause cell damage by inactivating the Akt-related cell survival pathway and release of cytochrome c, providing a new mechanism for curcumin-induced cytotoxicity.