Nasal Osteotomies Revisited in Asians: Surface Aesthetics, Anatomical and Technical Considerations.

Background Although osteotomy is commonly performed in rhinoplasty, it is difficult for less experienced surgeon to understand mechanism of the procedure. The primary goal of this study is to improve understanding of nasal osteotomy in Asians by considering the surface aesthetics and anatomy of the nose as well as their relationships with the surgical procedure. Methods Surface aesthetics, anatomic considerations, kinetics of medial and lateral osteotomy, fracture levels of osteotomy were discussed in detail by reviewing the previous publications and 18 years of our experience. Moreover, the technical details of osteotomy were explained and personal tips for performing successful osteotomy were described. Results Dorsal and lateral aesthetic lines, dorsal and basal widths are main characteristics related to the surface aesthetics of nose to perform the osteotomy. In addition, these features are different in Asian population due to the anatomic difference with Caucasians, which makes the procedure difficult and requires more attention to perform osteotomy. Conclusion Because osteotomy is one of the most traumatic and invasive part of the rhinoplasty, it is crucial for the rhinoplasty surgeon to understand the relationship between surface aesthetics and osteotomy techniques to produce consistent and reproducible results.

Heterogeneous and Monolithic 3D Integration of III-V-Based Radio Frequency Devices on Si CMOS Circuits.

Next-generation wireless communication such as sixth-generation (6G) and beyond is expected to require high-frequency, multifunctionality, and power-efficiency systems. A III-V compound semiconductor is a promising technology for high-frequency applications, and a Si complementary metal-oxide-semiconductor (CMOS) is the never-beaten technology for highly integrated digital circuits. To harness the advantages of these two technologies, monolithic integration of III-V and Si electronics is beneficial, so that there have been everlasting efforts to accomplish the monolithic integration. Considering that the on horizon 6G wireless communication requires faster and more energy-efficient system-on-chip technologies, it is imperative to realize a radio frequency (RF) system in which III-V technology and Si CMOS technology are integrated at a device level. Here we report heterogeneous and monolithic three-dimensional (3D) analog/RF-digital mixed-signal integrated circuits that contain two types of InGaAs high-electron-mobility transistors (HEMTs) designed for high fT and fMAX in the top and Si CMOS mixed-signal circuits consisting of an analog-to-digital converter and digital-to-analog converter in the bottom. A high unity current gain cutoff frequency of 448 GHz and unity power gain cutoff frequency of 742 GHz have been achieved by the fT oriented and fMAX oriented InGaAs HEMTs, respectively, without being affected by mixed-signal interference. At the same time, the bottom Si CMOS circuits provide valid signals without any performance degradation by the integration process.

Radiologic Analysis of Malar Arch Movement in Reduction Malarplasty Without Bony Resection.

BACKGROUND: Reduction malarplasty has been popular among Asians with a wide facial width. In general, malar setback after bony resection is regarded as the standard objective of reduction malarplasty. However, unnecessary bony resection may lead to various postoperative complications. Therefore, we suggest the use of reduction malarplasty without bony resection to achieve a similar narrowing effect of the facial width, based on radiographic analysis of malar arch movement. PATIENTS AND METHODS: This retrospective study analyzed 48 patients with a wide midface who underwent reduction malarplasty between September 2018 and December 2019. We included 40 cases of advancement repositioning malarplasty (AR) without bony resection and 8 cases of setback reduction malarplasty (SR) with bony resection. The three-dimensional position of the malar arch expressed by coordinates (x, y, and z) on three-dimensional computed tomography scans was used to compare the positional change between the surgical methods. The paired t-test, Wilcoxon text, and independent t-test were used in data analysis, and statistical analysis was performed using SPSS 23.0 software. RESULTS: Medial and superior movement of the freed malar arch segment was significantly different between AR and SR (P < 0.05). Although medialization and superiorization were not significantly different between AR and SR, there was a significant difference in anterior-posterior movement between AR and SR (P < 0.05). CONCLUSION: The radiologic analysis based on malar arch movement between AR and SR showed similar narrowing effects on medialization and superiorization of the malar arch regardless of bony resection. Therefore, the AR can be effectively applied in case of arch dominant type or malar asymmetry. In addition, further comprehensive study including analysis on movement of facial soft tissue following malar bony movement is expected based on this study in near future.

In Vitro and in Vivo Biocompatibility and Degradability Evaluation of Modified Polydioxanone Plate.

BACKGROUND: Polydioxanone (PDS) has been widely used in the medical field over the past 30 years. In the 2000s, PDS plate began to be used for rhinoplasty and septoplasty. However, in Asia PDS plates are not widely used due to lack of awareness and high prices. The authors devised a method of producing a modified PDS (m-PDS; Rhinoblock Material & Design Co., Gyeonggi-do, Sothh Korea) at low cost, and compared the biocompatibilities and degradabilities of plates produced with m-PDS and commercial PDS plates (Ethicon, Somerville, NJ) in vivo and in vitro. METHODS: The melting point and decomposition rate of m-PDS were determined by differential scanning calorimetry and thermogravimetric analysis and its tensile strength was also measured. Implants (1 cm × 1 cm × 0.15 mm sized) were inserted subcutaneously into mice and harvested en bloc 2, 5, 10, 15, or 25 weeks later. Tissues were stained with hematoxylin and eosin or Masson's trichrome to evaluate inflammation, extracellular matrix deposition, and vascularization, and plate degradability was also assessed. RESULTS: No significant difference was observed between the thermal analysis and tensile test results of m-PDS and PDS plates. m-PDS started to degrade in vivo from around 10 weeks, and commercial PDS plates from around 15 weeks. After 25 weeks in vivo, both products were completely degraded and not observed in tissue slides. Histologic analysis of excised specimens showed m-PDS and PDS were similar in terms of inflammation, extracellular matrix deposition, and vascularization. CONCLUSION: In vivo and in vitro experiments detected no significant difference between the biocompatibilities and degradabilities of modified and commercial PDS plates. The results of this study suggest that the modified PDS can be used to produce versatile, low cost, absorbable graft materials for rhinoplasty and septoplasty.

Evaluation of Auricular Cartilage Reconstruction Using a 3-Dimensional Printed Biodegradable Scaffold and Autogenous Minced Auricular Cartilage.

Auricular cartilage reconstruction represents one of the greatest challenges for otolaryngology-head and neck surgery. The native structure and composition of the auricular cartilage can be achieved by combining a suitable chondrogenic cell source with an appropriate scaffold. In reconstructive surgery for cartilage tissue, autogenous cartilage is considered to be the best chondrogenic cell source. Polycaprolactone is mainly used as a tissue-engineered scaffold owing to its mechanical properties, miscibility with a large range of other polymers, and biodegradability. In this study, scaffolds with or without autogenous minced auricular cartilage were implanted bilaterally in rabbits for auricular regeneration. Six weeks (n = 4) and 16 weeks (n = 4) after implantation, real-time quantitative reverse transcription polymerase chain reaction and histology were used to assess the regeneration of the auricular cartilage. Quantitative reverse transcription polymerase chain reaction analysis revealed that the messenger RNA expression of aggrecan, collagen I, and collagen II was higher in scaffolds with 50% minced cartilage than the scaffold-only groups or scaffolds with 30% minced cartilage (P < 0.05). Furthermore, histological analysis demonstrated significantly superior cartilage regeneration in scaffolds with the minced cartilage group compared with the scaffold-only and control groups (P < 0.05). Autogenous cartilage can be easily obtained and loaded onto a scaffold to promote the presence of chondrogenic cells, allowing for an improvement of the reconstruction of auricular cartilage. Here, the regeneration of auricular cartilage was also successful in the 50% minced cartilage group. The results presented in this study could have clinical implications, as they demonstrate the potential of a 1-stage process for auricular reconstruction.

Feasibility of a polydioxanone plate as an adjuvant material in rhinoplasty in Asians.

BACKGROUND: Nasal framework-supporting procedures such as septal extension grafts, derotation grafts, and columellar strut grafts are usually required in rhinoplasty in Asian patients because the skin envelope is tight, but the nasal framework is small and weak. Autologous materials are preferred, but they have some limitations related to the amount that can be harvested and the frequency of use. Therefore, synthetic materials have been used to overcome these limitations. METHODS: A total of 114 patients who received a polydioxanone (PDS) plate as an adjuvant material in rhinoplasty from September 2016 to August 2017 were retrospectively investigated. The PDS plate was used as to support the weak framework and to correct the contour of the alar cartilages. The PDS plate was used for reinforcement of columellar struts and septal L-struts, alar cartilage push-down grafts, fixation of septal extension grafts, and correction of alar contour deformities. RESULTS: Primary and secondary rhinoplasty was performed in 103 and 11 patients, respectively. Clinically, no significant inflammation occurred, but decreased projection of the tip was observed in seven patients and relapse of a short nose was noted in five patients. CONCLUSIONS: PDS plates have been used in the United States and Europe for more than 10 years to provide a scaffold for the nasal framework. These plates can provide reinforcement to columellar struts, L-struts, and septal extension grafts. In addition, they can assist in deformity correction. Therefore, PDS plates can be considered a good adjuvant material for Asian patients with weak and small nasal cartilage.

Understanding the Anatomy of the Transverse Nasalis Aponeurotic Fibers and Its Importance in Asian Rhinoplasty.

BACKGROUND: A complete release of the transverse nasalis aponeurotic fibers (TNAFs) during Asian rhinoplasty is critical for accurate positioning of the nasal implant and lengthening of the short nose. The objectives of this article are to clarify the anatomy of the TNAFs using cadaveric dissections and to present the clinical results after complete TNAF release in Asian rhinoplasty. METHODS: An anatomical dissection was performed in 8 cadavers to study the TNAFs, specifically the origin, insertion, and boundary of the TNAFs and the effect of the TNAF release on nasal length. Between January 2012 and December 2014, 2314 open implant augmentation rhinoplasties (1777 primary and 537 secondary) were performed by the senior author (J.J.). The records of these patients were retrospectively reviewed for results of TNAF release. A separately designed prospective clinical study was performed to document the nasal envelope extension after TNAF release in 52 consecutive patients. RESULTS: In the cadaver study, the anatomy and the boundaries of the TNAFs were clearly visualized and documented. With accurate release of the TNAFs, the ideal pocket for nasal implant can be defined, and the effect of the release of the TNAFs recorded. Release of the TNAFs also allows extension of the nasal envelope. However, measurements of the nasal envelope were not studied in the cadaver because the skin was degloved.From the clinical study with a follow-up ranging from 6 months to 1.5 years, the overall complication of open rhinoplasty using silicone implants incorporating TNAF release was 6%. In this group, 3.4% of patients required revision rhinoplasty. Releasing the TNAFs ensures an accurate implant pocket reducing the risk of implant deviation and implant visibility and increases the nasal length by 2.1 mm. CONCLUSIONS: Complete release of the TNAFs is especially important in Asian rhinoplasty to facilitate accurate pocket dissection, allowing the extension of the nasal envelope in order to correct short nose or secondary contracted nose.

Production of bio-oil rich in acetic acid and phenol from fast pyrolysis of palm residues using a fluidized bed reactor: Influence of activated carbons.

In this study, palm residues were pyrolyzed in a bench-scale (3kg/h) fast pyrolysis plant equipped with a fluidized bed reactor and bio-oil separation system for the production of bio-oil rich in acetic acid and phenol. Pyrolysis experiments were performed to investigate the effects of reaction temperature and the types and amounts of activated carbon on the bio-oil composition. The maximum bio-oil yield obtained was approximately 47wt% at a reaction temperature of 515°C. The main compounds produced from the bio-oils were acetic acid, hydroxyacetone, phenol, and phenolic compounds such as cresol, xylenol, and pyrocatechol. When coal-derived activated carbon was applied, the acetic acid and phenol yields in the bio-oils reached 21 and 19wt%, respectively. Finally, bio-oils rich in acetic acid and phenol could be produced separately by using an in situ bio-oil separation system and activated carbon as an additive.

Determination of sulfuric acid concentration for anti-cavitation characteristics of Al alloy by two step anodizing process to forming nano porous.

Al alloy is a highly active metal but forms a protective oxide film having high corrosion resistance in atmosphere environment. However, the oxide film is not suitable for practical use, since the thickness of the film is not uniform and it is severly altered with formation conditions. This study focused on developing an aluminum anodizing layer having hardness, corrosion resistance and abrasion resistance equivalent to a commercial grade protective layer. Aluminum anodizing layer was produced by two-step aluminum anodizing oxide (AAO) process with different sulfuric acid concentrations, and the cavitation characteristics of the anodized coating layer was investigated. In hardness measurement, the anodized coating layer produced with 15 vol.% of sulfuric acid condition had the highest value of hardness but exhibited poor cavitation resistance due to being more brittle than those with other conditions. The 10 vol.% of sulfuric acid condition was thus considered to be the optimum condition as it had the lowest weight loss and damage depth.