Search Results (14)

In the context of the quest for the Organic Laser Diode, we present the multiscale fabrication process optimization of mixed-order distributed-feedback micro-cavities integrated in nanosecond-short electrical pulse-ready organic light-emitting diodes (OLEDs). We combine ultra-short pulsed electrical excitation and laser micro-cavities. This requires the integration of a highly resolved DFB micro-cavity with an OLED stack and with microwave electrodes. In a second challenge, we tune the cavity resonance precisely to the electroluminescence peak of the organic laser gain medium. This requires precise micro-cavity fabrication performed using e-beam lithography to pattern gratings with a precision in the nanometer scale. Optimal DFB micro-cavities are obtained with 300 nm thick hydrogen silsesquioxane negative-tone e-beam resist on 50 nm thin indium tin oxide anode exposed with a charge quantity per area (i.e., dose) of 620 µC/cm², developed over 40 min in tetramethylammonium hydroxide diluted in water. We show that the integration of the DFB micro-cavity does not hinder the pulsed electrical operability of the device, which exhibits a peak current density as high as 14 kA/cm². Full article

The aim of this study is to highlight the changes that occur regarding dento-facial morphology, facial, and masticatory muscles in musicians who play wind instruments. Anatomical and functional changes may occur after the long-term use of each type of wind instrument. We considered studies of the impact of playing the wind instrument on the masticatory muscle activity and the resulting modifications. Both children and adults can be affected by playing wind instruments in regard to tooth positioning and facial morphology. These changes relate to the type of wind instruments, the type of vowels and tones used by instrumentalists. There most valuable breathing techniques have been identified that improve the redistribution of pressure, with a minimizing effect on the morphological changes in the oral cavity and cephalic extremity, implicitly on the masticatory functional disorders. In addition to these beneficial effects on the stomatognathic system, these breathing techniques favorably increase lung capacity. Furthermore, a series of toning exercises for neck muscles—which are actively involved and overworked by wind instrument-playing artists—was identified. The study concludes that less experienced instrumentalists demonstrate increased facial muscle engagement, possibly leading to excessive strain, while experienced instrumentalists exhibit more optimized patterns of muscle activity. The novelty of this research lies in its interdisciplinary approach to understanding the influence of wind instruments on dento-facial morphology, addressing preventive and corrective measures to mitigate undesirable outcomes. Full article

Obstructive sleep-disordered breathing (oSDB) comprises a set of breathing disturbances when the individual is asleep due to partial or complete upper airway obstruction. Modifying or risk factors are the anatomy, the size and shape of the airway, muscle tone, central nervous system responses to hypoxia, etc. In children, this is associated with poor school performance and reduced memory and learning abilities. In addition, increased levels of blood and lung pressure and cardiac alterations have been reported in children with sleep disturbances. On the other hand, Early Childhood Caries (ECC) is defined as the presence of one or more decayed primary teeth (cavities) of children under the age of 5. This study aimed to establish the possible relationship between sleep disorders and ECC by means of validated surveys and determined whether the results obtained coincide with the available literature. Our results found that up to 24.5% of children with a high risk of caries present regular nasal congestion, while this finding is only present among 6% of children with a low risk of caries (p = 0.041). The dmft index remains significantly linked to this occasional congestion, but the association depends on the patient’s level of risk (p = 0.008); increasing with a high increasing risk of caries. As a conclusion, the risk of early childhood caries could correlate to a specific sleep change such as occasional snoring. Full article

In this paper, a concept for an anthropomorphic replacement hand cast with silicone with an integrated sensory feedback system is presented. In order to construct the personalized replacement hand, a 3D scan of a healthy hand was used to create a 3D-printed mold using computer-aided design (CAD). To allow for movement of the index and middle fingers, a motorized orthosis was used. Information about the applied force for grasping and the degree of flexion of the fingers is registered using two pressure sensors and one bending sensor in each movable finger. To integrate the sensors and additional cavities for increased flexibility, the fingers were cast in three parts, separately from the rest of the hand. A silicone adhesive (Silpuran 4200) was examined to combine the individual parts afterwards. For this, tests with different geometries were carried out. Furthermore, different test series for the secure integration of the sensors were performed, including measurements of the registered information of the sensors. Based on these findings, skin-toned individual fingers and a replacement hand with integrated sensors were created. Using Silpuran 4200, it was possible to integrate the needed cavities and to place the sensors securely into the hand while retaining full flexion using a motorized orthosis. The measurements during different loadings and while grasping various objects proved that it is possible to realize such a sensory feedback system in a replacement hand. As a result, it can be stated that the cost-effective realization of a personalized, anthropomorphic replacement hand with an integrated sensory feedback system is possible using 3D scanning and 3D printing. By integrating smaller sensors, the risk of damaging the sensors through movement could be decreased. Full article

The effects of elastic cavity walls on noise generation at transonic speed are investigated for the generic M219 cavity. The flow is simulated with the Spalart–Allmaras (SA) improved delayed detached-eddy simulation (IDDES) turbulence model in combination with a wall function. The structural analysis software uses a modal formulation. The first 50 structural normal mode shapes are included in the simulation, spanning frequencies of 468–2280 Hz. Results are compared with those from a reference simulation with rigid cavity walls. A spectral analysis of pressure fluctuations from a microphone array above the cavity evinces a distinct tone at 816 Hz, which is absent in the reference simulation. Furthermore, the power of the 4th Rossiter mode at 852 Hz is depleted, implying a significant energy transfer from the fluid to the structure. Spectral proper orthogonal decomposition (SPOD) is employed for analyses of cavity wall pressure fluctuations and wall displacements. The SPOD mode energy spectra show results consistent with the spectra of the microphone array with respect to the tone at 816 Hz and the depletion of the energy at the 4th Rossiter mode. Furthermore, the SPOD mode energy spectra show energy spikes at additional frequencies, which coincide with structural eigenfrequencies. Full article

Non-volatile flavor precursors could be used to overcome the flavor loss problems of volatile flavor enhancers during long-term storage. Glu- and Phe-derived Amadori rearrangement products (ARPs) produce pleasant aroma tones thermally but are bitter. We used β-cyclodextrin (β-CD) for debittering Glu-Phe ARPs. ITC analysis indicated that CD-ARP complexes with 1:1 stoichiometry were obtained. NMR analysis indicated that the aromatic ring of Glu-Phe ARPs was embedded in the β-CD cavity. Molecular docking simulations of the bitter taste receptor hT2R1 showed that CD-ARP complex was inactive compared to Glu-Phe ARPs. Complexation with β-CD resulted in the thermal stabilization of Glu-Phe ARPs and a decrease in the degradation rate constant. Compared to Glu-Phe ARPs, the CD-ARP complex in the thermally treated food system slowed down the formation of browning compounds but didn’t inhibit flavor compound formation. The CD-ARP complex is a promising flavor enhancer for applications in flavored and heated foods. Full article

The symptomatology and diagnostic tools for osteomyelitis of the temporal bone have not been well documented. Diagnosis of early stage (i.e., mild form) osteomyelitis of the temporal bone may be delayed due to the limitations of traditional computed tomography’s (CT) imaging resolution. With the advancement of high-resolution CT (HRCT) images, clinicians can now observe images that could not be observed with traditional CT imaging. In this neuro-image report, we present three patients with refractory/untreatable tinnitus. In their HRCT images, mild osteomyelitis of the temporal bone was revealed by mucosa thickening with bony sequestration of air cells, mild opacification of the air cells, and soft tissue density in the middle ear cavity, mild opacification, and bony sequestration attributed to mucosa thickening of the mastoid air cells (along with the cortical bone). All of the clinical presentations and findings in the pure tone audiometry of the reported patients improved after adequate antibiotic treatment. The current report highlights the potential benefit of HRCT to diagnose this in such patients. In addition, immediate and conservative antibiotic treatment is recommended for managing these patients shortly after the detection of mild osteomyelitis of the temporal bone. This treatment could reduce the risk of progression to the severe form. Full article

Background: Recently, tooth deformities have been frequently encountered by pediatric dentists. Severe enamel hypomineralization sometimes induces pain such as hyperesthesia, but composite resin restoration is difficult because it often detaches without any cavity preparation. Resin-based hypersensitivity inhibitors for tooth physically seal the dentinal tubules. It was reported that hypersensitivity inhibitor containing novel adhesive monomers forms apatite and induces remineralization in vitro. Therefore, these case series assessed the clinical effects of remineralization and the suppression of hypersensitivity by Bio Coat Ca (Sun Medical, Shiga, Japan). Methods: After mechanical tooth cleaning was performed, the hypersensitivity inhibitors were applied and cured by light exposure. Changes in hypersensitivity were determined by visual analog scale (VAS). The improvement of hypomineralization was evaluated by the change in color tone based on the digital images of intraoral photographs. Results: After repeated monthly treatments, these cases showed decreased hypersensitivity after the fourth application, while the opaque white and brownish color improved on the seventh application. Conclusion: This novel hypersensitivity inhibitor with calcium salt of 4-methacryloxyethyl trimellitic acid (C-MET) and 10-methacryloyloxydecyl dihydrogen calcium phosphate (MDCP) not only suppressed hypersensitivity but also improved cloudiness and brown spots in recently erupted permanent teeth in presented cases. Full article

We numerically investigate spin-controlled vertical-cavity surface-emitting lasers (spin-VCSELs) for local oscillators, which are based on an injection locking technique used in coherent optical communications. Under the spin polarization modulation of an injection-locked spin-VCSEL, frequency-shifted and phase-correlated optical sidebands are generated with an orthogonal polarization against the injection light, and one of the sidebands is resonantly enhanced due to the linear birefringence in the spin-VCSEL. We determine that the peak strength and peak frequency in the spin polarization modulation sensitivity of the injection-locked spin-VCSEL depend on detuning frequency and injection ratio conditions. As a proof of concept, 25-Gbaud and 16-ary quadrature amplitude modulation optical data signals and a pilot tone are generated, and the pilot tone is used for the injection locking of a spin-VCSEL. An orthogonally-polarized modulation sideband generated from the injection-locked spin-VCSEL is used as a frequency-shifted local oscillator (LO). We verify that the frequency-shifted LO can be used for the homodyne detection of optical data signals with no degradation. Our findings suggest a novel application of spin-VCSELs for coherent optical communications. Full article

When air flows through pipe systems that include a corrugated segment, a whistling tone is generated and increases in intensity with increasing flow velocity. This whistling sound is related to the particular geometry of corrugated pipes, which is in the form of alternating cavities. This whistling is an environmental noise problem as well as a possible structural danger because of the resulting induced vibration. This paper studies the whistling behavior of various pipe systems with a combination of smooth and corrugated pipes through a series of experiments. The considered pipe systems consist of two smooth pipes attached at the upstream and downstream ends of a corrugated segment. Experiments with smooth and corrugated pipes, which had inner diameters of 15.25 and 16.5 mm, respectively, and various lengths, were performed for flow velocities of up to approximately 30 m/s. The minimum and maximum Strouhal numbers ($St$) obtained during our experiments were 0.25 and 0.38, respectively. For all pipe configurations investigated in this study, the lowest Mach number at which whistling was observed was 0.017, and the maximum was 0.093. The lowest frequency at which whistling was detected in our experiments was 650 Hz, and the highest was 3080 Hz. The results presented in the form of different variables and dimensionless parameters, including the frequency, Mach number, Strouhal number, and Helmholtz number. The average mode gap and number of excited acoustic modes were also taken into account for all considered configurations. The pipe systems with longer corrugated segments had broader whistling ranges than did configurations with shorter segments, indicating that the number of cavities inside the corrugated pipe has a direct effect on whistling. Increasing the smooth pipe length (either upstream or downstream) resulted in a decrease in the average mode gap between successive modes. The number of excited acoustic modes was primarily related to the corrugated segment length, but the smooth pipe length also had a pronounced effect on the excited modes for a constant corrugation length. The highest number of excited modes (13) was seen in the case of corrugated length 450 mm and smooth pipe length (either upstream or downstream) 400 mm while the lowest number of excited modes (1) was observed for corrugated length 250 mm and smooth pipe length (downstream) 300 mm and 400 mm. Full article

We present a comparative study of the capacity increase brought by bit- and power-loading discrete multi-tone (DMT) modulation for low-cost colorless transmitters. Three interesting reflective semiconductor optical amplifier (RSOA) based colorless transmitter configurations are compared: First, an amplified spontaneous emission (ASE) spectrum-sliced source; second, a self-seeded RSOA fiber cavity laser (FCL) and third, an externally seeded RSOA. With bit- and power-loaded DMT, we report record high line rates of 6.25, 20.1 and 30.7 Gbit/s and line rates of 4.17, 10.1 and 24.5 Gbit/s in a back-to-back and in a 25 km nonzero dispersion shifted fiber (NZDSF) transmission experiments for the three transmitter configurations, respectively. In all the experiments, BER (bit error ratios) below an FEC (forward error correction) limit of 7.5 × 10⁻³ were achieved. Full article

A plasma actuator comprising a dielectric layer sandwiched between upper and lower electrodes can induce a flow from the upper to lower electrode by means of an externally-applied electric field. Our objective is to clarify the mechanism by which such actuators can control the cavity tone. Plasma actuators, with the electrodes elongated in the streamwise direction and aligned in the spanwise direction, were placed in the incoming boundary of a deep cavity with a depth-to-length ratio of 2.5. By using this experimental arrangement, the amount of sound reduction (“control effect”) produced by actuators of differing dimensions was measured. Direct aeroacoustic simulations were performed for controlling the cavity tone by using these actuators, where the distributions of the body forces applied by the actuators were determined from measurements of the plasma luminescence. The predicted control effects on the flow and sound fields were found to agree well with the experimental results. The simulations show that longitudinal streamwise vortices are introduced in the incoming boundary by the actuators, and the vortices form rib structures in the cavity flow. These vortices distort and weaken the two-dimensional vortices responsible for producing the cavity tone, causing the tonal sound to be reduced. Full article

In polymer optical fiber (POF) systems, the nonlinear transfer function of the resonant cavity light emitting diode (RCLED) drastically degrades the communication performance. After investigating the characteristics of the RCLED nonlinear behavior, an improved digital look-up-table (LUT) pre-distorter, based on an adaptive iterative algorithm, is proposed. Additionally, the system parameters, including the bias current, the average electrical power, the LUT size and the step factor are also jointly optimized to achieve a trade-off between the system linearity, reliability and the computational complexity. With the proposed methodology, both the operating point and efficiency of RCLED are enhanced. Moreover, in the practical 50 m POF communication system with the discrete multi-tone (DMT) modulation, the bit error rate performance is improved by over 12 dB when RCLED is operating in the nonlinear region. Therefore, the proposed pre-distorter can both resist the nonlinearity and improve the operating point of RCLED. Full article

Finasteride is a 5α-reductase inhibitor widely used in present in the therapeutic approach of androgenic alopecia. Adverse effects consist in variable sign and symptoms, the most common being represented by mental troubles (reduced feeling of life pleasure or emotions, depression), physical impairments (loss of muscle tone and/or mass) and sexual complains (loss of libido and sexual potency). An increasing number of studies identify and describe even a post-finasteride syndrome (persistent adverse affects three months or more after finasteride cessation) or new adverse effects including but not limited at the skin level or oral cavity (marginal periodontium). We intend to present in this study several oral adverse effects encountered during finasteride administration, represented by mild and moderate signs which generally responded to topical procedures without to require the stop of the drug administration. New studies on large samples will further document the existing relation between the described oral adverse effects and the implied pathophysiological mechanisms. For this moment, we are taking into account as possible mechanisms- a direct action of finasteride administration, possible indirect consequences due to hormonal interferences, or coexisting factors with finasteride administration that were not detected. Full article