External Volume Expansion: Timing and Effects on the Rate of Fat Graft Retention in BALB/c Nude Mice.

BACKGROUND/AIM: Fat grafting has been widely used for soft-tissue augmentation. External volume expansion (EVE) is a favorable tool for improvement in the rate of fat graft retention. However, few studies have focused on the most appropriate time for its implementation. In this study, BALB/c nude mice were used to investigate the effective time for the implementation of external volume expansion to improve the rate of fat retention. MATERIALS AND METHODS: Sixteen mice were divided into four groups, and EVE was performed at different time points before or both before and after fat grafting. Fat tissue from a human donor was injected into the mice following EVE. Visual assessment, micro-computed tomography analysis, and histopathological evaluation were used to assess fat retention. RESULTS: After 10 weeks, the group that underwent EVE 5 days before fat grafting demonstrated a significantly higher preserved fat volume, as determined by micro-computed tomography (p<0.05). Moreover, the group that received additional EVE after fat grafting exhibited a higher retention rate compared to the groups receiving EVE only before grafting (p<0.05). Histopathological analysis indicated that swelling, edema, and inflammation were more pronounced in the group with EVE immediately before grafting, while angiogenesis and lipogenesis were more active in the group with additional EVE after grafting. CONCLUSION: EVE is a safe and effective approach for improving the rate of fat graft retentions. Furthermore, the timing of external tissue expansion plays a crucial role in fat retention. Based on our animal study, performing EVE immediately before and after fat grafting may be an effective strategy for enhancing the rate of fat graft retentions.

Extracranial Vascular Malformations Increase Cardiovascular Disease Risk: A Nationwide Population-Based Cohort Study.

BACKGROUND: Extracranial vascular malformations affect vessel inflammation, clotting, and ischemia. However, the relationship between extracranial vascular malformations and myocardial infarction (MI) or stroke has not been fully elucidated. Limited studies have investigated the association between extracranial vascular malformations and cardiovascular diseases. METHODS: A total of 48,701 patients with extracranial vascular malformations and a control cohort with 487,010 age- and sex-matched participants from the Korean National Health Insurance database were included. The incidence and risk of MI, ischemic stroke (IS), and hemorrhagic stroke (HS) between participants with extracranial vascular malformations and the control cohort was then compared. RESULTS: After adjusting for other cardiovascular disease risk factors, the adjusted hazard ratios (aHRs) for VMs, CMs, AVMs, and LMs in patients with acute MI were 1.25 [CI 1.04-1.50], 1.41 [CI 1.24-1.61], 1.68 [CI 1.18-2.37], and 1.40 [CI 1.31-1.48], respectively. For IS, the aHRs were 1.55 [CI 1.35-1.77], 1.92 [CI 1.74-2.11], 1.13 [CI 0.78-1.64], and 1.51 [CI 1.44-1.58], respectively. For HS, the aHRs were 1.51 [CI 1.12-2.05], 5.63 [CI 4.97-6.38], 2.93 [CI 1.82-4.72], and 1.34 [CI 1.20-1.50], respectively. CONCLUSIONS: Independent of cardiovascular risk factors, extracranial vascular malformations were associated with an increased risk of MI, IS, and HS. For patients with CMs and AVMs, intracerebral hemorrhage risk was particularly high, accounting for 563% and 293%, respectively. Therefore, even in patients with extracranial CMs or AVMs, performing diagnostic evaluations for cerebral AVMs and employing measures to prevent intracerebral hemorrhage are very crucial.

Free Vertical Latissimus Dorsi Flap for Tongue Reconstruction After Total Glossectomy.

BACKGROUND/AIM: The tongue is an important anatomical structure, playing an significant role in natural speech, swallowing, and sense of taste. Immediate reconstruction using autologous tissue must be performed following glossectomy for tongue cancer to improve patient quality of life. This study aimed to demonstrate the usefulness of a surgical technique using the free vertical latissimus dorsi flap (FvLDF) for tongue reconstructions using autologous tissue. PATIENTS AND METHODS: Among patients who underwent total glossectomy for tongue cancer from November 2014 to February 2023, we selected 10 patients who underwent immediate tongue reconstruction with a radial free forearm flap (RFFF) or free anterolateral thigh flap and four patients who underwent FvLDF. The patients were compared regarding postoperative function (width of oropharyngeal space in computed tomography, language-speech evaluation), aesthetic results, and features. RESULTS: All four patients who underwent FvLDF showed successful flap survival, with no severe complications. Because vertical incision was made during flap harvest with primary closure possible with the mid-axillary line, donor morbidity was significantly lower in patients who underwent reconstruction with FvLDF than in those who underwent reconstruction with RFFF, and good aesthetic results were obtained. In comparing the oropharyngeal space of patients on neck CT preoperatively and postoperatively, the width increase rate of patients who underwent reconstruction with FvLDF was significantly smaller. FvLDF patients demonstrated good speech and swallowing functions. CONCLUSION: Considering the advantages of reconstruction with FvLDF in terms of features and aesthetic results, this surgical technique may be a reliable alternative technique for tongue defects after glossectomy.

A nationwide cohort study on incidence and mortality associated with extracranial vascular malformations.

Extracranial vascular malformations are abnormal formations of blood vessels located outside the brain (extracranial) that develop during fetal development. They are caused by errors in the formation of blood vessels in the embryo and can affect various parts of the body, such as the head, neck, face, and other regions. Some malformations may be asymptomatic and only require monitoring, while others may cause significant health issues or cosmetic concerns and may need medical intervention. There are very few studies have investigated the nationwide incidence and quantitative mortality of vascular malformations in terms of their subtypes. Thus, this study aimed to determine the nationwide incidence and mortality associated with vascular malformations. This nationwide population-based study evaluated 70,517 patients with vascular malformations from 2008 to 2021. We evaluated the incidence and mortality associated with each subtype of vascular malformation. Furthermore, Cox regression analysis was used to evaluate the association between vascular malformation and mortality. The annual incidence (per 100,000 population) of overall vascular, venous, capillary, arteriovenous, and lymphatic malformations was 9.85, 1.48, 2.31, 0.24, and 5.82 cases, respectively. Patients with vascular malformations, except those with venous malformations, had higher mortality than the matched controls. Moreover, among the vascular malformation subgroups, the adjusted hazard ratio of mortality was the highest for arteriovenous malformations. This study revealed that the overall annual incidence of vascular malformations was 9.85 cases per 100,000 population in Korea from 2008 to 2021. The mortality of the matched general population was lower than that of patients with vascular malformations, except for those with venous malformations. Additionally, the adjusted hazard ratio for mortality associated with arteriovenous malformations was the highest among the vascular malformation subgroups.

Effects of Methylsulfonylmethane on UVB-induced Skin Damage: An Experimental Study in a Mouse Model.

BACKGROUND/AIM: The skin protects the body from ultraviolet rays and other external factors. Various studies have been conducted to identify methods to prevent skin aging and damage. To investigate the protective effects of methylsulfonylmethane (MSM), in this study, a hairless mouse model was used. PATIENTS AND METHODS: Mice divided into Groups B, C, and D were subjected to UVB irradiation for six weeks, and Group A was considered the control. Retinoic acid is a substance that has been proven to have anti-aging properties. Group C was injected with MSM, group D was injected with retinoic acid, and groups A and B were injected with saline. At the end of the experiment, the degree of senescence was confirmed through visual evaluation, histopathological analysis, immunohistochemistry, and elasticity measurement using SEM. RESULTS: After the end of the experiment, the wrinkle score was 0.4, 2.5, 1.8, 1.5 for Groups A, B, C, and D, respectively. Epidermal thickness was 40 µm, 70 µm, 60 µm, 55 µm in Groups A, B, C, and D, respectively. Group C showed less collagen confirmation loss and more angiogenesis and elastin precursor production. Elastic fiber linearity was 0.901±0.02, 0.551±0.04, 0.751±0.04, 0.822±0.03 for Groups A, B, C, and D, respectively. CONCLUSION: Injection of MSM in mice subjected to UVB-induced skin damage reduces the wrinkle score and protects against photoaging.

Bandgap tuning with thermal residual stresses induced in a quantum dot.

Lattice distortion induced by residual stresses can alter electronic and mechanical properties of materials significantly. Herein, a novel way of the bandgap tuning in a quantum dot (QD) by lattice distortion is presented using 4-nm-sized CdS QDs grown on a TiO2 particle as an application example. The bandgap tuning (from 2.74 eV to 2.49 eV) of a CdS QD is achieved by suitably adjusting the degree of lattice distortion in a QD via the tensile residual stresses which arise from the difference in thermal expansion coefficients between CdS and TiO2. The idea of bandgap tuning is then applied to QD-sensitized solar cells, achieving ≈60% increase in the power conversion efficiency by controlling the degree of thermal residual stress. Since the present methodology is not limited to a specific QD system, it will potentially pave a way to unexplored quantum effects in various QD-based applications.

Bandgap tuning by using a lattice distortion induced by two symmetries that coexist in a quantum dot.

Among the interests in the application of quantum dots (QDs), the bandgap tuning is of key importance in controlling their material properties. The bandgap of a QD can be adjusted by adopting a variety of different physicochemical methods. Herein, a novel way of the bandgap tuning is developed in an Ag2S-based QD system by suitably quenching the transformation from monoclinic Ag2S to cubic Ag and by subsequently inducing a lattice-distorted region of ≈1-nm-scale in a QD. The two distinct crystalline phases of Ag2S and Ag coexisting with the lattice-distorted region are experimentally demonstrated by visually showing this remarkable coexistence in a QD. A new approach is presented to the bandgap tuning (2.51 to 1.64 eV) and enhancing optical properties by suitably tailoring the degree of the lattice-distorted region in a QD. This conceptual method could pave a new way to utilizing quantum effects in various QD applications.

Bi-functional ion exchangers for enhanced performance of dye-sensitized solar cells.

Ion exchange using aerosol OT (AOT) offers dye adsorption twice as fast as known methods. Moreover, it suppresses the dye-agglomeration that may cause insufficient dye-coverage on the photoelectrode surface. Consequently, its dual function of fast dye-loading and higher dye-coverage significantly improves the power conversion efficiency of dye-sensitized solar cells.

Sea urchin TiO2-nanoparticle hybrid composite photoelectrodes for CdS/CdSe/ZnS quantum-dot-sensitized solar cells.

The sea urchin TiO(2) (SU TiO(2)) particles composed of radially aligned rutile TiO(2) nanowires are successfully synthesized through the simple solvothermal process. SU TiO(2) was incorporated into the TiO(2) nanoparticle (NP) network to construct the SU-NP composite film, and applied to the CdS/CdSe/ZnS quantum-dot-sensitized solar cells (QDSSCs). A conversion efficiency of 4.2% was achieved with a short-circuit photocurrent density of 18.2 mA cm(-2) and an open-circuit voltage of 531 mV, which corresponds to ∼20% improvement as compared with the values obtained from the reference cell made of the NP film. We attribute this extraordinary result to the light scattering effect and efficient charge collection.