Adaptability of melanocytes post ultraviolet stimulation in patients with melasma.

BACKGROUND: Dynamic in vivo changes in melanin in melasma lesions after exposure to ultraviolet (UV) irradiation have not been described. OBJECTIVES: To determine whether melasma lesions and nearby perilesions demonstrated different adaptive responses to UV irradiation and whether the tanning responses were different among different locations on face. METHODS: We collected sequential images from real-time cellular resolution full-field optical coherence tomography (CRFF-OCT) at melasma lesions and perilesions among 20 Asian patients. Quantitative and layer distribution analyses for melanin were performed using a computer-aided detection (CADe) system that utilizes spatial compounding-based denoising convolutional neural networks. RESULTS: The detected melanin (D) is melanin with a diameter >0.5 µm, among which confetti melanin (C) has a diameter of >3.3 µm and corresponds to a melanosome-rich package. The calculated C/D ratio is proportional to active melanin transportation. Before UV exposure, melasma lesions had more detected melanin (p = 0.0271), confetti melanin (p = 0.0163), and increased C/D ratio (p = 0.0152) in the basal layer compared to those of perilesions. After exposure to UV irradiation, perilesions have both increased confetti melanin (p = 0.0452) and the C/D ratio (p = 0.0369) in basal layer, and this effect was most prominent in right cheek (p = 0.030). There were however no significant differences in the detected, confetti, or granular melanin areas before and after exposure to UV irradiation in melasma lesions in all the skin layers. CONCLUSIONS: Hyperactive melanocytes with a higher baseline C/D ratio were noted in the melasma lesions. They were "fixed" on the plateau and were not responsive to UV irradiation regardless of the location on face. Perilesions retained adaptability with a dynamic response to UV irradiation, in which more confetti melanin was shed, mainly in the basal layer. Therefore, aggravating effect of UV on melasma was mainly due to UV-responsive perilesions rather than lesions.

The quantitative analysis of low-concentration (2%) ALA-PDT assisted with Q-switch 1064-nm Nd:YAG laser for acne vulgaris treatment.

Conventional 5-aminolevulinic acid-photodynamic (ALA-PDT) therapy (10-20%) has been widely applied for moderate-to-severe acne. The aim of this study is to investigate the effects of non-ablative Q-switched 1064-nm Nd:YAG laser-assisted ALA-PDT with low concentration (2%) on the treatment of acne vulgaris. Enrolled patients were randomly assigned to 2 groups. One group received combined therapy of 2% ALA-PDT and non-ablative Q-switched 1064-nm Nd:YAG laser, and the other received only 2% ALA-PDT. Patients in each group had received 3-session treatments with 4-week intervals (week 0, 4, and 8). Sebum secretion, melanin index, erythema index, and transepidermal water loss (TEWL) were assessed at week 2, 8, 12, and 24. VISIA® skin image system score and global esthetic improvement scale (GAIS) were also evaluated. Twenty-four participants were enrolled and evenly randomized to two groups. Significant improvement in sebum secretion was noted in combined therapy group compared to the monotherapy group at week 12 (37.5% versus 16.3%), and the improvement would still be noted until week 24 (18.3% versus 17.4%). Combined group also showed more severe melanin index and erythema index after treatment. For VISIA® skin analysis, patients in combined group had better percentile ranking in porphyrins and red-light images. There were no significant differences in GAIS at the end of the follow-up between each group, whereas higher proportion of satisfaction was noted in combined group at week 2. With the assistance of laser, low concentrations (2%) of 5-ALA can provide effective phototoxic reactions in treating acne vulgaris. The satisfaction of patients is high with acceptable adverse effects.

An Entropy-Balanced Orthogonal Learning Bamboo Forest Growth Optimization Algorithm with Quasi-Affine Transformation Evolutionary and Its Application in Capacitated Vehicle Routing Problem.

The bamboo forest growth optimization (BFGO) algorithm combines the characteristics of the bamboo forest growth process with the optimization course of the algorithm. The algorithm performs well in dealing with optimization problems, but its exploitation ability is not outstanding. Therefore, a new heuristic algorithm named orthogonal learning quasi-affine transformation evolutionary bamboo forest growth optimization (OQBFGO) algorithm is proposed in this work. This algorithm combines the quasi-affine transformation evolution algorithm to expand the particle distribution range, a process of entropy increase that can significantly improve particle searchability. The algorithm also uses an orthogonal learning strategy to accurately aggregate particles from a chaotic state, which can be an entropy reduction process that can more accurately perform global development. OQBFGO algorithm, BFGO algorithm, quasi-affine transformation evolutionary bamboo growth optimization (QBFGO) algorithm, orthogonal learning bamboo growth optimization (OBFGO) algorithm, and three other mature algorithms are tested on the CEC2017 benchmark function. The experimental results show that the OQBFGO algorithm is superior to the above algorithms. Then, OQBFGO is used to solve the capacitated vehicle routing problem. The results show that OQBFGO can obtain better results than other algorithms.

Aberration analysis of a projection-type CGH display with an expanded FOV based on the HOE screen.

This paper proposed a holographic optical element as a see-through screen for the computer-generated hologram projection system with 3D images. The proposed holographic screen consisted of a linear grating and a lens phase. The linear grating is used to redirect the information light and guide information into the observer's eye and achieve the see-through function. The lens phase is used to magnify the field of view of the holographic projection system. The aberration caused by the screen was analyzed in this paper and the aberration can be pre-corrected in the hologram calculation algorithm. Finally, the proposed system achieved 20.3 by 14.3 degrees field of view at 532 nm laser based on the spatial light modulator with 6.4 µm pixels.

Photoaging and Sequential Function Reversal with Cellular-Resolution Optical Coherence Tomography in a Nude Mice Model.

Although nude mice are an ideal photoaging research model, skin biopsies result in inflammation and are rarely performed at baseline. Meanwhile, studies on antiphotoaging antioxidants or rejuvenation techniques often neglect the spontaneous reversal capacity. Full-field optical coherence tomography (FFOCT) can acquire cellular details noninvasively. This study aimed to establish a photoaging and sequential function reversal nude mice model assisted by an in vivo cellular resolution FFOCT system. We investigated whether a picosecond alexandrite laser (PAL) with a diffractive lens array (DLA) accelerated the reversal. In the sequential noninvasive assessment using FFOCT, a spectrophotometer, and DermaLab Combo®, the photodamage percentage recovery plot demonstrated the spontaneous recovery capacity of the affected skin by UVB-induced transepidermal water loss and UVA-induced epidermis thickening. A PAL with DLA not only accelerated skin barrier regeneration with epidermal polarity, but also increased dermal neocollagenesis, whereas the nonlasered group still had >60% collagen intensity loss and 40% erythema from photodamage. Our study demonstrated that FFOCT images accurately resemble the living tissue. The photoaging and sequential function reversal model provides a reference to assess the spontaneous recovery capacity of nude mice from photodamage. This model can be utilized to evaluate the sequential noninvasive photodamage and reversal effects after other interventions.

A Comparison of the Use of Two-Dimensional and Three-Dimensional Visualization Systems by Novice and Experienced Microsurgeons in Microsurgical Vessel Anastomosis: An Analysis Using the Chicken Model.

BACKGROUND: Various studies have discussed the benefits of applying three-dimensional (3D) techniques, specifically its advantages with respect to ergonomics, feasibility, and the rate of learning achievable in microsurgery training. However, no study has been conducted that compares the operator experience of using two-dimensional (2D) and 3D systems in microsurgical training. The aim of this study is to compare 2D- and 3D-assisted microsurgical training in novices based on anastomosis of chicken femoral arteries. METHODS: The participants were grouped by previous microsurgical experience. Group A includes novice participants. Group B includes 2D-experienced participants. Group C includes both participants in groups A and B. A questionnaire composed of 10 parameters in the field of image quality, dexterity, ergonomic, and feasibility will be filled out after each participant finished their anastomoses by the 2D and 3D systems. RESULTS: The results demonstrated 3D system was scored better on "field of view" (p = 0.004), "less tremor" (p = 0.005), "neck/upper back comfort" (p = 0.043), "lower back comfort" (p = 0.015), "technical feasibility" (p = 0.020), and "educational feasibility" (p = 0.004) in group A (N = 12). In group B (N = 9), 3D system was scored better on "field of view" (p = 0.041) but worse on "image resolution" (p = 0.031). CONCLUSION: With the 3D visualization system for microsurgical anastomosis of chicken femoral model, there are significant improvements in the field of view, stability, ergonomics, and educational value compared with 2D system among all participants. Accordingly, 3D-assisted microsurgery training can be a novel and potential popular training method.

Molecular Characteristics and Distribution of Virulence Genes among Staphylococcus aureus Complex Isolates Derived from Vascular Access Infections.

Staphylococcus aureus is a major human pathogen that produces various virulence factors which promote the binding of bacteria to tissues and medical devices such as vascular access devices, thereby developing a wide range of invasive infections. Vascular access serves as an entry site for S. aureus and elevates the risk of infection in the hemodialysis population. Nevertheless, the distribution of virulence genes in Staphylococcus spp. associated with vascular access infections (VAIs) has not been studied previously. In this study, we determined the relationship between the molecular characteristics and virulence profiles of S. aureus isolates obtained from VAIs. We collected isolates from patients with VAIs between August 2017 and December 2020 and further analyzed the molecular characteristics, antimicrobial resistance profiles, and virulence gene distribution in the isolates. Overall, 15 sequence types (STs), including a new ST (ST6892) and 19 spa types, were identified among the 56 isolates. Of the 53 S. aureus isolates, ST8, ST239, ST45, and ST59 were the predominant STs, whereas ST2250 was the only ST in 3 S. argenteus isolates. ST45-SCCmecIV-t026 (abbreviated as ST45-IV-t026), ST59-V-t437, and ST8-IV-t008 were the predominant clones that belonged to agr type I. All isolates harbored clfB and eno, whereas all S. aureus isolates harbored clfA. In addition, 10 Panton-Valentine leucocidin-positive isolates belonged to ST8 and ST59, with ST8-IV-t008 and ST59-V-t437 being the predominant clones. In brief, the distribution of virulence genes associated with STs may assist in the spread of molecular types of Staphylococcus spp.

Binocular dynamic holographic floating image display.

This paper proposes a binocular holographic floating display. The device consists of two phase-modulation spatial light modulators (SLM) and a dihedral corner reflector array (DCRA) element. The conjugate images of the SLMs generated by the DCRA become the system's exit pupils. Exit pupils that are larger than the pupils of human eyes are arranged to locate at the position of observer's eyes. Therefore, the dimension of the SLM will not limit the viewing angle, although the pixel pitch of the SLM still limits the maximum field of view. For the laser light source, the resolution of the images can achieve 3 arc minutes when the distance between images and DCRA is less than 20 cm. The full-color display function is also performed in the proposed device.

Functional recovery in human partial thickness skin wounds after application of multicomponent hydrolipidic film (MAS063DP): A prospective, open-label, comparative clinical trial.

Acute and minor skin wounds are common in daily life. However, in clinical practice, after initial management in the acute phase, the wounds are managed mainly through observation, and the patients are usually lost to follow-up. Considering a multicomponent hydrolipidic dressing (MAS063DP) long-known for its safe application in eczema and recently in laser-induced wounds, we aimed to evaluate its ability in functional recovery of impaired skin integrity during wound healing. Sixteen patients (N = 16) were enrolled and completed (n = 8 vs n = 8) this prospective, open-label, vehicle-controlled clinical trial with 12-week follow-up. Transepidermal water, skin viscoelasticity and bioimpedance analysis were measured initially, at the 1st, 4th, 8th, and 12th weeks. Improvements in these parameters were greater in the MAS063DP group (from 31.4 ± 9.0 to 16.4 ± 4.3 g/m2 h, P < .001; from 77 ± 16% to 88 ± 9%, P < .05; from 4182 ± 3823 to 2644 ± 1772 Ω) than in the white petrolatum group. No significant adverse events occurred, and all participants were more satisfied with the intervention. In this study, MAS063DP can restore skin integrity and reinstitute physiologic function as a feasible and safe intervention more markedly than management through observation during the healing process by providing protective hydrolipidic layer on the skin with simultaneous anti-inflammatory and antioxidant activities from its key ingredients such as glycyrrhetinic acid, Vitis vinifera, telmesteine, and vitamins C and E.

Quantitative Outcome Assessment of Color Match and the Extent of Repigmentation after Pixel Array Epidermal Grafting for Head and Neck Stable Vitiligo: A Prospective Cohort Study.

BACKGROUND: Epidermal grafting with an automatic harvesting system has been reported as a simple and efficacious procedure for stable vitiligo. However, no prospective cohort study has quantitatively evaluated the color matching and extent of repigmentation in the head and neck area by this method. OBJECTIVE: To evaluate the color matching and extent of repigmentation after pixel array epidermal grafting by image analysis software and physicians' naked eye. METHODS: Ten Asian patients with head and neck vitiligo lesions stable for at least 6 months were treated with pixel array epidermal grafting with an automatic harvesting system and post-grafting phototherapy. The patients were evaluated 1, 3, and 6 months post grafting for the percentage of repigmentation by blinded physicians' assessment and image analysis software. The color matching index of repigmentation was evaluated by measuring the melanin index in the grafted area and the juxta non-vitiliginous area. RESULTS: The average blister harvest time was 46.3 ± 9.7 min. The area percentile of repigmentation by the image analysis software were 32.3 ± 26.8, 64.6 ± 29.4, and 76.5 ± 25.9 at 1, 3, and 6 months post grafting, respectively. There were no significant differences between the physicians' assessments and the results from the image analysis software. The change in the area percentile of repigmentation between 3 and 6 months post grafting was only statistically significant using image analysis software. The grafted area achieved a color match of 83.1 ± 13.4% that of the juxta non-vitiliginous area 6 months after grafting. Three patients had repigmentation of leukotrichia. CONCLUSION: By quantitative measurement, uniform pixel array micrografts provide a very good extent of repigmentation and color match in the head and neck area. Image analysis software revealed a steady increase in repigmentation after POM3 until POM6, which was not detected by subjective assessment.

Photoaging Reversibility in Asian Patients With Melasma Treated Using Picosecond Lasers With a Diffractive Lens Array: A 1-Year Prospective Observational Cohort Study.

BACKGROUND: Picosecond lasers appear to be effective and safe in treating pigmentation and photoaging disorders through laser-induced optical breakdown. OBJECTIVE: To analyze the feasibility of photorejuvenation using picosecond lasers with diffractive lens array (DLA) in patients with melasma. METHODS: Ten Asian (N = 10) women with melasma and Fitzpatrick skin Type IV were enrolled and treated using 755-nm picosecond alexandrite lasers with DLA. All individuals were assessed before treatment, and at 12, 20 weeks, and 1 year by post-hoc test on melasma area and severity index (MASI) and with VISIA Complexion Analysis System using percentile rank for measurement. RESULTS: The median participant age was 46.5 years. The average MASI continually and significantly (p < .05) decreased until the 1-year follow-up, with the photoaging characteristics, such as wrinkles and red areas improving simultaneously (p < .05). Spots, texture, pores, ultraviolet (UV) spots, brown spots, and porphyrins exhibited alleviation, but this improvement relapsed by the 1-year follow-up. No postinflammatory hyperpigmentation or hypopigmentation occurred. CONCLUSION: In patients with melasma, picosecond laser treatment with DLA may alleviate pigmentation disorder and the related photoaging characteristics (e.g., wrinkled skin and increased vascularity), and the effects may be maintained for a long time. Nevertheless, post-treatment clinical visits every 3 to 6 months are recommended.

Dual-wavelength fiber-optic technique to assist needle cricothyroidotomy.

The traditional needle cricothyroidotomy procedure is performed blindly without any medical equipment. Complications including posterior tracheal wall perforation, accidental vessel puncture, and missed tracheal puncture are reported. Therefore, we proposed a dual-wavelength fiber-optic technique based on the technique of near-infrared spectroscopy to assist operators performing needle cricothyroidotomy in a swine model. We embedded optical fibers in a 16-gauge intravenous needle catheter. Real-time data were displayed on an oscilloscope, and we used the program to analyze the data immediately. The change of optical density corresponding to 690-nm and 850-nm wavelengths and hemoglobin parameters (HbO2 and Hb concentrations) was analyzed immediately using the program in the laptop. Unique and significant optical differences were presented in this experiment. We could easily identify every different tissue by the change of optical density corresponding to 690-nm and 850-nm wavelengths and hemoglobin parameters (HbO2 and Hb concentrations). Statistical method (Kruskal-Wallis H test) was used to compare differences in tissues at each time-point, respectively. The p values in every tissue in optical density change corresponding to 690 nm and 850 nm were all < 0.001. Furthermore, the p values in every tissue in Hb and HbO2 were also all < 0.001. The results were statistically significant. This is the first and novel study to introduce a dual-wavelength embedded fibers into a standard cricothyroidotomy needle. This proposed system might be helpful to provide us real-time information of the advanced needle tip to decrease possible complications.

Applying Noncontact Sensing Technology in the Customized Product Design of Smart Clothes Based on Anthropometry.

Electrocardiograms (ECGs) provide important information for diagnosing cardiovascular diseases. In clinical practice, the conventional Ag/AgCl electrode is generally used; however, it is not suitable for long-term ECG measurement because of the risk of allergic reactions on the skin and the dying issue of electrolytic gels. In previous studies, several dry electrodes have been proposed to address these issues. However, most dry electrodes, which are the mode of conductive materials, have to contact the skin well and are easily affected by motion artifacts in daily life. In the smart clothes developed in this study, a noncontact electrode was used to assess the biopotential across the clothes to prevent skin irritation and discomfort. Moreover, a three-dimensional parametric model based on anthropometric data was built, and the technique of customized product design was introduced into the smart clothes development process to reduce the influence of motion artifacts. The experimental results show that the proposed smart clothes can maintain a good ECG signal quality stably under motion from different activities.

Novel Wireless Bioimpedance Device for Segmental Lymphedema Analysis Post Dual-Site Free Vascularized Lymph Node Transfer: A Prospective Cohort Study.

An innovative wireless device for bioimpedance analysis was developed for post-dual-site free vascularized lymph node transfer (VLNT) evaluation. Seven patients received dual-site free VLNT for unilateral upper or lower limb lymphedema. A total of 10 healthy college students were enrolled in the healthy control group. The device was applied to the affected and unaffected limbs to assess segmental alterations in bioimpedance. The affected proximal limb showed a significant increase in bioimpedance at postoperative sixth month (3.3 [2.8, 3.6], p = 0.001) with 10 kHz currents for better penetration, although the difference was not significant (3.3 [3.3, 3.8]) at 1 kHz. The bioimpedance of the affected distal limb significantly increased after dual-site free VLNT surgery, whether passing with the 1 kHz (1.6 [0.7, 3.4], p = 0.030, postoperative first month; 2.8 [1.0, 4.2], p = 0.027, postoperative third month; and 1.3 [1.3, 3.4], p = 0.009, postoperative sixth month) or 10 kHz current ((1.4 [0.5, 2.7], p = 0.049, postoperative first month; 3.2 [0.9, 6.3], p = 0.003, postoperative third month; and 3.6 [2.5, 4.1], p < 0.001, postoperative sixth month). Bioimpedance alterations on the affected distal limb were significantly correlated with follow-up time (rho = 0.456, p = 0.029 detected at 10 kHz). This bioimpedance wireless device could quantitatively monitor the interstitial fluid alterations, which is suitable for postoperative real-time surveillance.

Reduced External Iliac Venous Blood Flow Rate Is Associated with Asymptomatic Compression of the Common Iliac Veins.

Background and Objectives: Compression of the common iliac veins (CIV) is not always associated with lower extremity symptoms. This study analyzed this issue from the perspective of patient venous blood flow changes using quantitative flow magnetic resonance imaging. Materials and Methods: After we excluded patients with active deep vein thrombosis, the mean flux (MF) and mean velocity (MV) of the popliteal vein, femoral vein, and external iliac vein (EIV) were compared between the left and right sides. Results: Overall, 26 of the patients had unilateral CIV compression, of which 16 patients had symptoms. No significant differences were noted in the MF or MV of the veins between the two sides. However, for the 10 patients without symptoms, the EIV MF of the compression side was significantly lower than the EIV MF of the non-compression side (p = 0.04). The receiver operating characteristic curve and chi-squared analyses showed that when the percentage difference of EIV MF between the compression and non-compression sides was ≤-18.5%, the relative risk of associated lower extremity symptoms was 0.44 (p = 0.016). Conclusions: If a person has compression of the CIV, a decrease in EIV blood flow rate on the compression side reduces the rate of symptom occurrence.

Astigmatism correction and quality optimization of computer-generated holograms for holographic waveguide displays.

In this manuscript, the astigmatism of the waveguide combiner with a pair of symmetry HOEs was analyzed. The light field can be predicted by the modified convolution formulation of Fresnel diffraction when the information of light passes through the astigmatism causing element. Then the astigmatism can be corrected. The theory was experimentally proved by the system with a phase-only SLM and a diffraction planar waveguide. Furthermore, the image quality of astigmatism corrected phase-type CGHs can be improved via the iteration process. Since the coherence of light source was employed, the temporal averaging method was utilized to avoid speckle noise.

A Novel Smart Assistance System for Blood Vessel Approaching: A Technical Report Based on Oximetry.

In clinical practice, the catheter has to be placed at an accurate position during anesthesia administration. However, effectively guiding the catheter to the accurate position in deeper tissues can be difficult for an inexperienced practitioner. We aimed to address the current issues associated with catheter placement using a novel smart assistance system for blood vessel catheter placement. We used a hollow introducer needle embedded with dual wavelength (690 and 850 nm) optical fibers to advance the tip into the subclavian vessels in anesthetized piglets. The results showed average optical density changes, and the difference between the absorption spectra and hemoglobin concentrations of different tissue components effectively identified different tissues (p < 0.05). The radial basis function neural network (RBFNN) technique was applied to distinguish tissue components (the F-measure value and accuracy were 93.02% and 94%, respectively). Finally, animal experiments were designed to validate the performance of the proposed system. Using this system based on oximetry, we easily navigated the needle tip to the target vessel. Based on the experimental results, the proposed system could effectively distinguish different tissue layers of the animals.

Using Wireless Near-Infrared Spectroscopy to Predict Wound Prognosis in Diabetic Foot Ulcers.

OBJECTIVE: To use wearable near-infrared spectroscopy (NIRS) to determine the effect of Buerger exercises on diabetic foot ulcer (DFU) healing. METHODS: Study authors enrolled 50 consecutive patients in a 1-year prospective observational study of DFUs. The patients were divided into groups by their arterial statuses: group A (no peripheral arterial disease [PAD]), group B (PAD without angioplasty), and group C (PAD with angioplasty). Tissue perfusion was assessed through wireless wearable NIRS to determine the effects of Buerger exercises on wound healing. MAIN RESULTS: The patients in group C were older, were more likely to have had an amputation, and had more severe wounds than did the patients in other groups. The requirements of insulin injection for diabetes mellitus control differed significantly (P = .024) among the three groups. At the end of the survey, 19 patients (38%) had unhealed DFUs. The NIRS revealed that most nonhealed patients in groups B and C shared higher resting hemoglobin levels and tissue blood volume and lower tissue oxygen concentration, which indicated inflammation accompanied by higher blood flow and oxygen consumption. Notably, the nonhealed patients in group C showed paradoxically reduced hemoglobin and tissue blood volume after the exercises. CONCLUSIONS: Although DFUs remain a challenge to treat, NIRS may prove valuable in predicting wound healing by identifying risk factors for poor wound prognosis, such as reduced hemoglobin and tissue blood volume after exercise.

Cerebral Oxygenation during Exercise in Patients with Cardiopulmonary Diseases: A Prospective Observational Study.

BACKGROUND: The relationship between exercise and cerebral oxygenation has gained increasing attention. However, few studies have investigated the correlation between exercise and cerebral oxygenation in patients with cardiopulmonary diseases. OBJECTIVES: To investigate the correlation between exercise and cerebral oxygenation in patients with cardiopulmonary diseases. METHODS: Thirty eligible patients with cardiopulmonary diseases underwent incremental cardiopulmonary exercising test (CPET) and near-infrared spectroscopy with both right and left sensors placed at the mid forehead to detect oxygen saturation of cerebral tissue (STO2). Parameters of cerebral oxygenation and exercise intensity were collected and analyzed. RESULTS: The average age of the patients was 51.17 ± 10.21 years and included 23 males and 7 females. The average maximal STO2 of the left and right brain during CPET were 51.850 ± 1.57% and 51.755 ± 1.90%, respectively. Meanwhile, mean oxygen consumption (VO2) while reaching maximal STO2 was 4.42 ± 1.05 metabolic equivalents (METs) over the left brain and 4.34 ± 1.17 METs over the right brain. The exercise intensity upon reaching maximal STO2 was 84.91 ± 11.70% over the left brain and 83.16 ± 14.64% over the right brain. Peak VO2 was significantly correlated to VO2 upon reaching maximal STO2 over the left and right brain (R = 0.805, p < 0.001 and R = 0.739, p < 0.001, respectively). Age was significantly negatively correlated to VO2 upon maximal STO2 over the left and right brain (R = -0.378, p = 0.039 and R = -0.513, p = 0.004, respectively). CONCLUSIONS: Cerebral oxygenation increases with higher exercise intensity, and it reaches a maximal STO2 between respiratory compensation point and peak exercise. The higher the peak VO2, the better the VO2 upon reaching maximal STO2.