Three-dimensional electronic microfliers inspired by wind-dispersed seeds.

Large, distributed collections of miniaturized, wireless electronic devices1,2 may form the basis of future systems for environmental monitoring3, population surveillance4, disease management5 and other applications that demand coverage over expansive spatial scales. Aerial schemes to distribute the components for such networks are required, and-inspired by wind-dispersed seeds6-we examined passive structures designed for controlled, unpowered flight across natural environments or city settings. Techniques in mechanically guided assembly of three-dimensional (3D) mesostructures7-9 provide access to miniature, 3D fliers optimized for such purposes, in processes that align with the most sophisticated production techniques for electronic, optoelectronic, microfluidic and microelectromechanical technologies. Here we demonstrate a range of 3D macro-, meso- and microscale fliers produced in this manner, including those that incorporate active electronic and colorimetric payloads. Analytical, computational and experimental studies of the aerodynamics of high-performance structures of this type establish a set of fundamental considerations in bio-inspired design, with a focus on 3D fliers that exhibit controlled rotational kinematics and low terminal velocities. An approach that represents these complex 3D structures as discrete numbers of blades captures the essential physics in simple, analytical scaling forms, validated by computational and experimental results. Battery-free, wireless devices and colorimetric sensors for environmental measurements provide simple examples of a wide spectrum of applications of these unusual concepts.

Anthropometric Analysis of the Faces of Chinese Women in Leadership Roles.

The aim of this study was to investigate the appearance of the faces of Chinese women in leadership positions through an anthropometric analysis of Women of China from 1949 to 2022. Photographs of cover women of Women of China were gathered and a total of 380 frontal and 101 lateral photographs were collected. The photographs were divided into 3 time phases: phase I (1949-1978): from the launch of Women of China magazine, up until the time of reform and opening; phase II (1978-2010): from the time of reform and opening until when Google China was blocked; and phase III (2010-2022): to the present. The horizontal corneal diameter (11.52 mm) was set as the reference value for the frontal face. The anthropometric results showed the width of the face, midface, and lower face decreased over time. The women at phase I had larger and round faces, smaller and narrower eyes, wider noses, and thicker lips; relatively masculine and hard-working woman image, as the occupations of women were mainly described as workers, farmers, and civil servants. Phase II showed smaller but still round faces, relatively wide-set round eyes, narrower noses, and smaller lips than in phase I; neutral features as skilled workers, engineers, entrepreneurs, civil servants, and researchers. Phase III showed oval faces, almond eyes, narrower noses, smaller full lips, and wider chins, reflecting a process of feminization; working in entertainment, sports, and science. The data from this study might serve as the recommended aesthetic proportions when performing plastic surgical procedures for talented woman.

Anthropometric analysis of the faces of Chinese beauty pageant winners, from the early 20th century to the present.

The aim of this study was to investigate the aesthetic characteristics of Chinese beauty through an anthropometric analysis of beauty pageant winners from 1952 to 2021. Photographs from 5 renowned Chinese beauty pageants (Miss World Pageant, Miss Earth Pageant, Miss Universe Pageant, Miss International Pageant, and Miss Chinese Cosmos Pageant) were gathered and a total of 294 frontal and 31 lateral photographs were collected. The photos were divided into 3 time phases: phase I (1952-1977): from the first time when Chinese girls participated in beauty pageants, up until the time of reform and opening; phase II (1978-2002): from reform and opening to the re-opening of the Miss Chinese Cosmos Pageant; phase III (2003-2021): to the present. The horizontal corneal diameter (11.52 mm) was set as the reference value for the frontal face. Among the 35 anthropometric items of frontal faces (26 distances and 9 angles) and 41 anthropometric items of lateral faces (33 distances and 8 angles), 21 anthropometric items (16 distances and 5 angles) and 8 proportional indices of frontal faces showed significant differences. On lateral pictures, 2 angles showed significant differences among the 3 phases. Regarding the anthropometric measurements that decreased across the 3 phases, the width of the face, midface, and lower face exhibited the greatest changes. The lower face width showed the most striking changes, with a decrease from 128.5 to 112.0 mm. The quadratic regression revealed a significant turning point after 1978, coinciding with the period of Chinese reform and opening, which had a profound impact on aesthetics.

Digital Compression of the Origin of the Nasal Branch of the Ophthalmic Artery During Filler Augmentation: A Review of the Anatomical Literature and an Analysis of Plastinated Specimens.

The aim of this study was to determine the exact site of digital compression on the origin of the nasal branch of the ophthalmic artery during filler augmentation, by conducting a review of anatomical literature and examining plastinated specimens. According to 4 textbooks (Gray's Anatomy, Whitnall's Anatomy on the Human Orbit, Wolff's Anatomy, and Duke-Elder's System of Ophthalmology), the dorsal nasal artery leaves the orbit by piercing the orbital septum between the trochlea and the medial palpebral ligament and anastomoses with the angular part of the facial artery. In plastinated arterial specimens, the ophthalmic artery exits the orbit and divides into the supratrochlear artery and the dorsal nasal artery at the upper border of the lacrimal fossa. The dorsal nasal artery then anastomoses with the angular part of the facial artery. Branches of the dorsal nasal artery anastomose with their counterparts on the opposite side. During filler augmentation of the nose, bilateral digital compression is applied to the origins of the nasal branches of the ophthalmic artery, specifically at the point where the ophthalmic artery pierces the orbital septum. Applying compression just above the medial palpebral ligament against the bone, directly above the lacrimal sac, using the index finger and thumb can help prevent the migration of injected droplets to the ophthalmic artery. This straightforward maneuver, grounded in anatomical understanding, aims to prevent the migration of injected droplets to the ophthalmic artery.

Freeing and Stretching the Palatine Vessels From the Greater Palatine Foramen in Palatoplasty.

The aim of this paper is to present how to free and stretch the palatine vessels from the greater palatine foramen in palatoplasty. After a mucoperiosteal flap is raised, periosteal elevator is passed behind the palatine vessels to detach the periosteum around the vessels. Then, a blunt right-angle instrument is placed behind the palatine vessels, and the vessels are pulled from the foramen in the superior aspect, slightly forward (63 degrees) and medially (19 degrees) according to the direction to the greater palatine canal (GPC). The nasal mucosa is also released from the hard palate and from the lateral pharyngeal wall. After dividing the palatal aponeurosis and elevating the anterior flap, the first suture is inserted through the nasal layer of the mucosa at the level of the posterior border of the hard palate (A suture). The nasal layer is approximated and sutured. After the closure of the buccal layer, the 2 posterior flaps are joined to the small anterior flap. Finally, A suture is tied. In 60 cases of pushback palatoplasty, the palatine vessels were stretched from the greater palatine foramen. In literatures, the length of GPC is 26.97 mm. Anteroposterior diameter of the upper opening of GPC is 3.88 mm. The angle between the vertical plane and the axis of GPC is 19.09 degrees. The angle between the transverse plane and the axis of GPC is 62.63 degrees. Probably, this information is the values obtained in adults. As a matter of fact, similar values were obtained in our study on this subject.

The Distribution of the Nerves and Arteries of the Platysma for Clinical Applications.

This study aimed to provide anatomical data on the platysma for clinical procedures. The authors obtained 25 specimens from 15 adult Korean cadavers (9 men, 6 women; mean age, 72 years; range, 61-85 years). Lines connecting the gonion with the gnathion (G-GN) and the acromial end (acromial end of the clavicle) with the sternal end (sternal end of the clavicle) were used as references. Modified Sihler staining was used to trace the nerves distributed in the platysma. The superior border values of the platysma were 12.1 ± 2.7 mm, 31.5 ± 5.3 mm, 42.4 ± 5.6 mm, and 61.7 ± 6.4 mm, respectively, for sections 2 through 5 on the G-GN line. The inferior border values of the platysma were 83.6 ± 19.1 mm, 80.1 ± 14.0 mm, 74.8 ± 14.5 mm, 67.2 ± 13.7 mm, and 54.6 ± 7.1 mm, respectively, for the 5 sections on the acromial end of the clavicle-sternal end of the clavicle line. In the hyoid bone, cricoid cartilage, and jugular notch, the mean distance between the bilateral platysma was 14.4 ± 2.2 mm, 22.6 ± 10.6 mm, and 51.1 ± 15.7 mm, respectively. The mean angle at the cervical branch of the facial nerve and the anterior border of the sternocleidomastoid muscle sternal head was 28.7 ± 2.6 degrees and 53.4 ± 7.7 degrees from the G-GN line, respectively. The upper third of the platysma was supplied by branches of the facial artery and submental artery. The middle third was supplied by branches of the occipital artery and received its direct blood supply from branches of the external carotid artery. The lower third was supplied by branches of the transverse cervical artery. The authors hope that the results of this study will be helpful for rejuvenation procedures of the neck.

Impact of Short Sleep Duration on the Incidence of Obesity and Overweight among Children and Adolescents.

Background and Objectives: The prevalence of obesity among children is increasing and is highlighting many problems. Lack of sleep is common among children and adolescents. Although several studies have investigated sleep duration and overweight and obesity from a sex perspective, data regarding age and sex effects remain limited and inconclusive. This study aimed to evaluate the risk(s) for overweight or obesity according to sleep duration among children and adolescents; to evaluate the effect of short sleep duration on the incidence of overweight/obesity among children and adolescents; and to evaluate sex differences in the risk of overweight or obesity with shorter sleep durations. Materials and Methods: The PubMed database was searched for relevant studies published up to June 30, 2021. Odds ratios for obesity/overweight were estimated for short compared with long sleep duration. Subgroup analysis based on sleep duration, sex, and study location was also performed. Results: The estimated odds ratio for combined obesity and overweight was 1.171 (95% confidence interval (CI) 1.092−1.256) according to short sleep duration. Obesity/overweight with short sleep duration was significantly prevalent in the <6 and 6−10 years' subgroups (odds ratio 1.226 (95% CI 1.083−1.387) and 1.341 (95% CI 1.175−1.530), respectively). Among boys, short sleep duration was significantly correlated with a high occurrence of obesity/overweight (odds ratio 1.294 (95% CI 1.153−1.452)); no such correlation was found among girls. Conclusions: Short sleep duration may increase risk of obesity among children and adolescents, especially those <6 and 6−10 years of age. In the subgroup analysis, the incidence of obesity/overweight for short sleep time revealed significant results among Asians and boys.

The Nasolabial Area Shown on Histology and P45 Sheet Plastination.

ABSTRACT: The aim of this study was to elucidate the relationships between the nasolabial fold and superficial fascia on histology and P45 sheet plastination.Two centimeter width specimen of the nasolabial area were harvested from the skin to periosteum. Then, 10-µm sections were made, stained with Masson trichrome, and observed under a light microscope. Three head and neck specimens were sliced in horizontal sections (46 slices) using P45 sheet plastination (polyester resin corrosion-resistant method designed to preserve biological sectional specimens in situ). Through slicing, bleaching, dehydration, casting, forced impregnation, curing, cutting, and sanding the molds, P45 plastination provided good light transmission, allowing the internal structures within the sheet to be revealed clearly in their intact form.The observations on histology and P45 sheet plastination correlated well. The nasolabial fold consisted of the superficial fatty layer of superficial fascia (SFS). At the beginning of the alar groove level, the nasolabial groove was located on the point where the medial limit of SFS met the levator labii superioris. At the alar base level, the nasolabial groove was located where the medial limit of the SFS met levator labii superioris. At the mouth corner level, the nasolabial groove was located where the medial limit of the SFS met the modiolus, including the orbicularis oris. The superficial fascia became scanty near the nasolabial groove, and the SFS comprised the nasolabial fold.The results of the present study may be helpful for applying subcutaneous dissection or sub-superficial muscular aponeurotic system dissection in rejuvenation of the nasolabial area.

Morphological Boundaries of the Parotid Gland in Koreans.

ABSTRACT: This study aimed to examine the accurate location and boundary of the parotid gland in Koreans.Forty hemifaces from embalmed cadavers (mean age: 73 years) were studied. The line connecting the porion, gonion, and gnathion was used as a reference line. To measure the boundary of the parotid gland, the Frankfort horizontal line was used as the x-axis, whereas the vertical line passing through the porion was used as the y-axis. All measurements were taken from the lateral side of the face.The parotid gland has a variety of shapes: irregular, reverse triangle, and falciform. In all specimens, the boundary of the parotid gland was located 20 to 60 mm below the Frankfort horizontal line and located 10 mm anterior to the y-axis. On average, the most anterior and posterior distances of the parotid gland from the porion-gonion line were 36.4 ±â€Š13.9 mm and 20.1 ±â€Š10.5 mm, respectively, and the most inferior distance of the parotid gland from the gonion-gnathion line was 9.8 ±â€Š5.8 mm. All specimens of parotid glands were found within an area 20 to 40 mm below the Frankfort horizontal line and 10 mm to the left of the y-axis. The most anterior point of the parotid gland was observed at varying locations. The maximum value of the most anterior point was 61.26 mm; it rarely exceeded the ectocanthion. The most posterior points of the parotid gland were located between the mastoid process and sternocleidomastoid muscle.These results might be useful for preventing injury to the parotid gland during facial rejuvenation procedures.

Illustrations in the Journal of Craniofacial Surgery.

The aim of this study is to analyze the medical illustrations that appeared in the Journal of Craniofacial Surgery (JCFS) during the last 3 years (2016-2018).All illustrations in 2676 articles from 24 issues were analyzed.In total, 363 articles (13.6%) contained illustrations (for total of 589 illustrations), and 38 articles (1.4%) cited illustrations from other articles. The number of illustrations increased over time (152 in 2016, 181 in 2017, and 256 in 2018; P = 0.007). The signature of the illustrator appeared in 16.5% of the illustrations, and the illustrator's name was acknowledged in 7.6%. The most frequent contents of the 589 illustrations were surgical procedures (55.4%), followed by anatomy (34.1%). Among the 555 illustrations showing regions of the body, the most frequently illustrated region was the oral cavity (41.6%), followed by the eye and periorbital region (18.4%), the nose (12.4%), and the head (11.4%). Of the 555 illustrations showing tissue, the tissue most frequently depicted was bone (52.8%), followed by soft tissue (42.5%). The mean score for clarity of the intended message was 3.5 ±â€Š1.2. The mean score for artistic skill was 3.2 ±â€Š1.0.As the number of illustrations in JCFS increases, it is increasingly important that information on the illustrators be given. The journal editor should recommend that authors provide the illustrators' information. From the author's perspective, the best illustration is one that tells the story the author wants to convey to readers. Therefore, the crucial point is the expression of the author's goal, rather than the esthetics of the illustration.

Platysmaplasty: Is it Possible to Pull the Platysma Effectively in the Medial or Lateral Direction?

The aim of this study was to investigate whether it is possible to pull the platysma effectively in the medial or lateral direction (medial platysmaplasty and lateral platysmaplasty) and to explore the anatomical basis of those findings.Six hemifaces from 3 fresh cadavers were dissected. After skin removal, the platysma was pulled upward and in the medial or lateral direction with the ulnar side of the palm. Its mobility was checked. In 2 volunteers, using wooden bar, the skin overlying platysma was pulled in superomedial and superolateral direction.The platysma ran diagonally from the acromio-deltoid region to the perioral and submental area. In all hemifaces, the platysma was attached to the mandible along its course. The platysma inserted into the mandibular body. At its medial portion (approximately halfway medially from the mentum to the angle; 4-5 cm), the attachment was so firm that it could not be moved horizontally. The posterolateral portion of the platysma was indirectly attached to the mandible and movable. In cadaver, platysma did not move much when it was pulled in the medial direction. In the lateral direction, however, platysma did move well. In living body, when skin overlying platysma was pulled in superomedial direction and superolateral direction, 3 points marked on mandibular border moved about 1.5-2.0 cm and 2.0-2.5 cm respectively.It is thought that medial platysmaplasty can correct anterior neck deformities and redistribute neck skin mainly in the submental area, while that lateral platysmaplasty can pull the cheek skin in superolateral direction.

A Theoretical and Empirical Investigation of Design Characteristics in a Pb(Zr,Ti)O3-Based Piezoelectric Accelerometer.

A theoretical and experimental study on the design-to-performance characteristics of a compression-mode Pb(Zr,Ti)O3-based piezoelectric accelerometer is presented. Using the metamodeling to approximate the relationship between the design variables and the performances, the constituent components were optimized so that the generated electric voltage, representing sensitivity, could be maximized at different set values of the resonant frequency (25-40 kHz). Four kinds of optimized designs were created and fabricated into the accelerometer modules for empirical validation. The accelerometer modules fabricated according to the optimized designs were highly reliable with a broad range of resonant frequency as well as sufficiently high values of charge sensitivity. The fixed (or mounted) resonant frequency was between 16.1-30.1 kHz based on the impedance measurement. The charge sensitivity decreased from 296.8 to 79.4 pC/g with an increase of the resonant frequency, showing an inverse relation with respect to the resonant frequency. The design-dependent behaviors of the sensitivity and resonant frequency were almost identical in both numerical analysis and experimental investigation. This work shows that the piezoelectric accelerometer can be selectively prepared with best outcomes according to the requirements for the sensitivity and resonant frequency, fundamentally associated with trade-off relation.

Aging of the bony orbit in East Asians: a three-dimensional computed tomographic study.

PURPOSE: The purpose of this study was to evaluate age-related changes of orbital rim in Koreans and construct a reference data set for the aging phenomenon in Asians. METHODS: Data were collected from computed tomography (CT) scans of orbits and facial bones obtained from 107 Korean (55 males and 52 females) at intervals of 0.60 mm. Subjects was categorized according to sex and age as follows: young group (20-35 years) and old group (60 years and above). CT scans were reconstructed via three-dimensional (3D) modeling programs. The most lateral, medial, superior and inferior points of orbital rim were used as reference points. The orbital aperture area in each 3D model was measured using an analytical software program such as 3-Matic. RESULTS: The orbital aperture height showed no overall statistically significant difference (P > 0.05) with age in either sex. Changes were irregular with a combination of decrease and increased components. The mean change did not exceed about 0.1 mm. The orbital aperture area showed no significant change with increasing age in either male or female study populations. CONCLUSIONS: In this study, there was no significant enlargement of the orbital rim with increasing age in Koreans. The measurement data in the present study differ from previous studies involving White subjects, which revealed a significant increase in orbital aperture area.

Design Optimization of Bulk Piezoelectric Acceleration Sensor for Enhanced Performance.

While seeking to achieve high performances of a bulk piezoelectric acceleration sensor, we investigated the behavior of the design variables of the sensor components and optimized the sensor design using a numerical simulation based on piezoelectric analysis and metamodeling. The optimized results demonstrated that there was an exponential dependency in the trade-off relation between two performance indicators, the electric voltage and the resonant frequency, as induced by the design characteristics of the sensor. Among the design variables, a decrease in the base height and epoxy thickness and an increase in the piezo element's inner diameter had a positive effect on two performances, while the head dimensions (diameter and height) exhibited the opposite effect on them. The optimal sensor designs are proposed within the valid range of resonant frequency (25-47.5 kHz). Our redesign of a commercial reference sensor improved the resonant frequency by 13.2% and the electric voltage by 46.1%.

Chronic administration of ketamine ameliorates the anxiety- and aggressive-like behavior in adolescent mice induced by neonatal maternal separation.

Ketamine has long been used as an anesthetic agent. However, ketamine use is associated with numerous side effects, including flashbacks, amnesia, delirium, and aggressive or violent behavior. Ketamine has also been abused as a cocktail with ecstasy, cocaine, and methamphetamine. Several studies have investigated therapeutic applications of ketamine, demonstrating its antidepressant and anxiolytic effects in both humans and rodents. We recently reported that neonatal maternal separation causes enhanced anxiety- and aggressive-like behaviors in adolescent. In the present study, we evaluated how acute and chronic ketamine administration affected the behavioral consequences of neonatal maternal separation in adolescent mice. Litters were separated from dams for 4 hours per day for 19 days beginning after weaning. Upon reaching adolescence (post-natal day 35-49), mice were acutely (single injection) or chronically (7 daily injections) treated with a sub-anesthetic dose (15 mg/kg) of ketamine. At least 1 h after administration of ketamine, mice were subjected to open-field, elevated-plus maze, and resident-intruder tests. We found that acute ketamine treatment reduced locomotor activity. In contrast, chronic ketamine treatment decreased anxiety, as evidenced by increased time spent on open arms in the elevated-plus maze, and remarkably reduced the number and duration of attacks. In conclusion, the present study suggests that ketamine has potential for the treatment of anxiety and aggressive or violent behaviors.

The distributed pattern of the neurovascular structures around clavicle to minimize structural injury in clinical field: anatomical study.

INTRODUCTION: The aim of this study was to determine the location and distribution pattern of neurovascular structures superior and inferior to the clavicle by detailed dissection. METHODS: Fifteen adult non-embalmed cadavers with a mean age of 71.5 years were studied. For measurements, the most prominent point of the sternal end of the clavicle (SEC) on anterior view and the most prominent point of the acromial end of the clavicle (AEC) were identified and divided five equal sections before dissection. A line connecting the SEC and AEC was used as a reference line. The surrounding neurovascular structures were investigated. RESULTS: The supraclavicular nerve was mainly distributed in the second and the third sections (distribution frequency: 41.30% and 30.43%, respectively) from AEC. Branches of the thoracoacromial artery were mainly distributed in the second, third, and fourth sections (distribution frequency: 21.15%, 26.92%, and 28.85%, respectively). Branches of the subclavian vein were mainly distributed in the third and fourth sections (distribution frequency: 23.26 and 30.23%, respectively). Distribution frequency of subclavian vein, subclavian artery, and brachial plexus ranged from 31.3 to 57.5%. DISCUSSION: When the clavicle was divided into five sections, there was relatively little distribution of neurovascular damage in the first section or the fifth section. This study reveals the average location of subclavian vein with artery and brachial plexus. Results of this study could be used as reference during surgery.

A rare branching pattern of hindgut: absence of inferior mesenteric artery.

The arterial system of the gastrointestinal tract has many variations. However, variation in the inferior mesenteric artery (IMA) is less common than for the other abdominal arteries. The case in the present cadaver subject showed a variation in the anatomy of the IMA that differed from those seen in previous studies, because it did not originate from the abdominal aorta and had no branches. A single artery arising from branches of the inferior pancreaticoduodenal and middle colic arteries supplied the hindgut. This variation generated blood vessels along the digestive tract during the later stages of development. The marginal artery of the colon in this case probably was more highly developed instead of the IMA. It is clinically important to know the range of variations, as these data are used in the diagnosis and treatment of abdominal diseases. This hitherto unknown variation might affect the health of patients, and we recommend radiographic examinations for diagnosis and treatment.

Investigating skin penetration depth and shape following needle-free injection at different pressures: A cadaveric study.

BACKGROUND AND OBJECTIVES: The effectiveness of needle-free injection devices in neocollagenesis for treating extended skin planes is an area of active research. It is anticipated that needle-free injection systems will not only be used to inject vaccines or insulin, but will also greatly aid skin rejuvenation when used to inject aesthetic materials such as hyaluronic acid, botulinum toxin, and placental extracts. There has not been any specific research to date examining how materials penetrate the skin when a needle-free injection device is used. In this study, we investigated how material infiltrates the skin when it is injected into a cadaver using a needle-free device. STUDY DESIGN/MATERIALS AND METHODS: Using a needle-free injector (INNOJECTOR™; Amore Pacific, Seoul, Korea), 0.2 ml of 5% methylene blue (MB) or latex was injected into cheeks of human cadavers. The device has a nozzle diameter of 100 µm and produces a jet with velocity of 180 m/s. This jet penetrates the skin and delivers medicine intradermally via liquid propelled by compressed gasses. Materials were injected at pressures of 6 or 8.5 bars, and the injection areas were excised after the procedure. The excised areas were observed visually and with a phototrichogram to investigate the size, infiltration depth, and shape of the hole created on the skin. A small part of the area that was excised was magnified and stained with H&E (×40) for histological examination. RESULTS: We characterized the shape, size, and depth of skin infiltration following injection of 5% MB or latex into cadaver cheeks using a needle-free injection device at various pressure settings. Under visual inspection, the injection at 6 bars created semi-circle-shaped hole that penetrated half the depth of the excised tissue, while injection at 8.5 bars created a cylinder-shaped hole that spanned the entire depth of the excised tissue. More specific measurements were collected using phototrichogram imaging. The shape of the injection entry point was consistently spherical regardless of the amount of pressure used. When injecting 5% MB at 6 bars, the depth of infiltration reached 2.323 mm, while that at 8.5 bars reached 8.906 mm. The area of the hole created by the 5% MB injection was 0.797 mm(2) at 6 bars and 0.242 mm(2) at 8.5 bars. Latex injections reached a depth of 3.480 mm at 6 bars and 7.558 mm at 8.5 bars, and the areas were measured at 1.043 mm(2) (6 bars) and 0.355 mm(2) (8.5 bars). Histological examination showed that the injection penetrated as deep as the superficial musculoaponeurotic system at 6 bars and the masseter muscle at 8.5 bars. CONCLUSION: When injecting material into the skin using a pneumatic needle-free injector, higher-pressure injections result in a hole with smaller area than lower-pressure injections. The depth and shape of skin penetration vary according to the amount of pressure applied. For materials of low density and viscosity, there is a greater difference in penetration depth according to the degree of pressure. Lasers Surg. Med. 48:624-628, 2016. © 2016 Wiley Periodicals, Inc.

Where to fix in rejuvenation surgeries?: tensile strength of the periosteum.

The aim of this study is to elucidate the tensile strength of the periosteum relating to facial rejuvenation surgeries.Twelve hemifaces of 6 formalin-fixed Korean adult cadavers were used. Two horizontal incision lines were made 3 cm above the supraorbital rim and 1 cm below the infraorbital rim. Another 2 vertical incisions were on the medial orbital rim and 2 cm lateral to the lateral orbital rim. Elevated flaps were turned over, and the undersurfaces of the periosteum were exposed. A silk string was passed below the periosteum with a 3-mm bite and wound. A 3-cm loop was made, and this was pulled away using the tensiometer. The breaking strength was measured.The breaking strengths of the periosteum were different according to the location (P = 0.000, analysis of variation). The strongest point was 2 cm above the supraorbital rim at the medial one third of the orbit (14.05 [2.50] N) followed by 1 cm above the frontozygomatic suture (13.35 [4.70] N). The weakest point was the infraorbital rim at the lateral one third of the orbit (6.93 [3.76] N) followed by the lateral orbital rim at the level of the lateral canthus (7.60 [3.49] N). Breaking strengths of the periosteum of the medial side (11.44 [3.83] N) were significantly greater (P = 0.021, t-test) than the lateral side (9.32 [3.76] N). In the supraorbital area, the breaking strengths of the periosteum of the upper points (12.91 [3.00] N) were significantly greater (P = 0.000, t-test) than the lower points (9.36 [2.76] N).The results of this study can be of use when choosing a fixation point in rejuvenation surgeries.

Skin tension related to tension reduction sutures.

The aim of this study was to compare the skin tension of several fascial/subcutaneous tensile reduction sutures. Six upper limbs and 8 lower limbs of 4 fresh cadavers were used. At the deltoid area (10 cm below the palpable acromion) and lateral thigh (midpoint from the palpable greater trochanter to the lateral border of the patella), and within a 3 × 6-cm fusiform area of skin, subcutaneous tissue defects were created. At the midpoint of the defect, a no. 5 silk suture was passed through the dermis at a 5-mm margin of the defect, and the defect was approximated. The initial tension to approximate the margins was measured using a tensiometer.The tension needed to approximate skin without any tension reduction suture (S) was 6.5 ± 4.6 N (Newton). The tensions needed to approximate superficial fascia (SF) and deep fascia (DF) were 7.8 ± 3.4 N and 10.3 ± 5.1 N, respectively. The tension needed to approximate the skin after approximating the SF was 4.1 ± 3.4 N. The tension needed to approximate the skin after approximating the DF was 4.9 ± 4.0 N. The tension reduction effect of approximating the SF was 38.8 ± 16.4% (2.4 ± 1.5 N, P = 0.000 [ANOVA, Scheffé]). The tension reduction effect of approximating the DF was 25.2% ± 21.9% (1.5 ± 1.4 N, P = 0.001 [ANOVA, Scheffé]). The reason for this is thought to be that the SF is located closely to the skin unlike the DF. The results of this study might be a basis for tension reduction sutures.