Changes in Cerebral Oxygenation in the Prefrontal Cortex During Cardiopulmonary Exercise Testing in Patients After Cardiovascular Surgery.

Oxygenated haemoglobin (O2Hb) and total haemoglobin (THb) concentrations rise with increasing exercise load during the cardiopulmonary exercise test (CPX); however, this elevated response is impaired in patients with chronic heart failure. Furthermore, the changes occurring in patients during the acute phase of cardiac surgery are unknown. This study aimed to measure cerebral oxygenation in the prefrontal cortex (PFC) during CPX in patients during the acute post-operative phase following cardiovascular surgery. Fourteen patients in the acute phase of post-cardiovascular surgery period were enrolled. CPX was administered between the post-operative period and discharge. The protocol employed the ramp method (10 W/min) after 3-min rest and 3-min warm-up periods. Levels of O2Hb, deoxygenated haemoglobin (HHb), THb, and the regional cerebral oxygen saturation (rSO2) in the PFC were measured from the resting state through the end of CPX using near-infrared spectroscopy. The mean values of O2Hb, HHb, and THb levels and rSO2 were compared at rest, warm-up, anaerobic threshold, and peak points. At the peak, O2Hb and rSO2 declined significantly, and HHb rose significantly compared to the respective values at rest; no significant changes were observed in THb. These findings suggest that the oxygen supply to the PFC is reduced in patients with reduced cardiac function following cardiovascular surgery.

Synthesis of AZO-Coated ZnO Core-Shell Nanorods by Mist Chemical Vapor Deposition for Wastewater Treatment Applications.

AZO-coated ZnO core-shell nanorods were successfully fabricated using the mist chemical vapor deposition method. The influence of coating time on the structural, optical, and photocatalytic properties of zinc oxide nanorods was investigated. It was observed that the surface area of AZO-coated ZnO core-shell nanorods increased with an increase in coating time. The growth orientation along the (0001) crystal plane of the AZO thin film coating was the same as that of zinc oxide nanorods. The crystallinity of AZO-coated ZnO core-shell nanorods was significantly improved as well. The optical transmittance of AZO-coated ZnO core-shell nanorods was greater than 55% in the visible region. The degradation efficiency for methyl red dye solution increased with an increase in coating time. The highest degradation efficiency was achieved by AZO-coated ZnO core-shell nanorods with a coating duration of 20 min, exhibiting a degradation rate of 0.0053 min-1. The photodegradation mechanism of AZO-coated ZnO core-shell nanorods under ultraviolet irradiation was revealed.

Changes in Medial Elbow Joint Space When Elbow Valgus Stress Is Applied at Different Limb Positions and Loads In Vivo.

BACKGROUND: Ulnar collateral ligament (UCL) injury is a common sports injury among overhead-throwing athletes and causes medial elbow pain and instability. UCL injury is generally diagnosed based on symptoms, physical findings, and image evaluation. To standardize the method for evaluating elbow valgus instability, more information is needed regarding changes in the medial elbow joint space (JS) in healthy elbows. PURPOSE/HYPOTHESIS: The purpose of this study was to measure the JS during the application of elbow valgus stress at different elbow flexion angles and loads and to clarify the presence of defensive muscle contractions during elbow valgus stress. It was hypothesized that the JS will differ according to different limb positions and loads and that defensive contractions will occur when elbow valgus stress is >90 N. STUDY DESIGN: Controlled laboratory study. METHODS: Elbow joints on the nondominant side were examined in 20 healthy male university students (mean age, 21 ± 0.2 years) at 30°, 60°, and 90° of elbow flexion. To create valgus stress on the elbow, loads of 30, 60, 90, 120, and 150 N were applied with a Telos stress device and with gravity stress on the forearm. The medial JS was measured ultrasonographically during the application of elbow valgus stress. Electrodes were attached to the pronator teres muscle, and defensive muscle contractions were measured using electromyography during the application of elbow valgus stress. Repeated-measures analysis of variance and paired t tests were used to compare the JS at each elbow angle and each valgus stress load, and the Bonferroni method was used as a post hoc test. RESULTS: At 30° of elbow flexion, the JS was significantly higher at 30 N versus 0 N and at 60 N versus 0 or 30 N (P ≤ .018 for all). At 60° of flexion, the JS was significantly higher at 30 N versus 0 N, at 60 N versus 0 and 30 N, and at 90 N versus 0, 30, and 60 N (P ≤ .024 for all). At 90° of elbow flexion, the JS was significantly higher at 30 N versus 0 N and at 60 N versus 0 and 30 N (P ≤ .028 for all). Defensive muscle contraction did not occur at any elbow flexion angles at elbow valgus stress ≤60 N. CONCLUSION: The lack of muscular contraction at elbow valgus stress ≤60 N may reflect the function of the medial collateral ligament. CLINICAL RELEVANCE: Elbow valgus stress ≤60 N allows for the evaluation of the joint opening.

Influence of Continuous Elbow Valgus Stress on the Medial Elbow Joint Space.

BACKGROUND: To investigate the effect of ulnar collateral ligament stretching due to the "creep phenomenon," the effect of accumulating elbow valgus stress on ligaments must be clarified. PURPOSE: To evaluate the effect of continuous elbow valgus stress on the medial elbow joint space (JS). STUDY DESIGN: Controlled laboratory study. METHODS: The authors measured the JS of the nondominant elbow joints of 20 healthy male university students (age, 21.4 ± 0.5 years; height, 171.4 ± 6.5 cm; weight, 65.7 ± 9.1 kg). The participants were seated with their shoulder at 90° of abduction and external rotation and their elbow at 30° of flexion, and elbow valgus stress was maintained at loads of 30 and 60 N using a Telos stress device. The JS was measured on ultrasound images of the medial elbow joint with the elbow in the start limb position (0 N) and then immediately (0 seconds) and at 60, 120, 180, 240, and 300 seconds after loading. In addition, muscle activity of the pronator teres muscle during JS measurement was monitored to examine the presence or absence of defensive contraction due to pain. Analysis of variance and the Bonferroni method for post hoc testing were used for statistical analysis. RESULTS: No participants showed defensive contractions of the pronator teres. At 30 N, JS was significantly larger 60 seconds after loading compared with immediately after loading (P = .007). At 60 N, JS was significantly larger after 120 seconds, as the loading time of valgus stress increased, compared with immediately after loading (P = .002). CONCLUSION: JS was significantly larger immediately after loading of valgus stress, with an increase in continuous elbow valgus stress after 60 seconds at 30 N and after 120 seconds at 60 N. These results suggest that a creep phenomenon may develop around the soft tissue of the elbow when loaded by a continuous valgus stress. CLINICAL RELEVANCE: JS is significantly increased by continuous elbow valgus stress.

[Modulation of central sudomotor control by short-term heat acclimation as evidenced by frequency of sweat expulsions].

The purpose of this study was to examine changes in the control of sweating by heat acclimation by using frequency of sweat expulsion (Fsw), an index of central sudomotor activity. Eight healthy young volunteers underwent a six-day heat acclimation program [a total of 80-min exercise at 50% peak rate of oxygen consumption in the heat (36 degrees C)]. In the days before and after the heat acclimation program, we examined the local sweating rate (SR) at the chest and forearm, Fsw and esophageal temperature (Tes) during whole body heating using a water-perfused suit. Heat acclimation decreased (P < 0.01) the Tes thresholds for initiation of chest and forearm sweating. Heat acclimation did not change the slopes of the SR at either site or Fsw versus Tes during heating, but shifted the slopes to a lower Tes. Heat acclimation did not change the slopes of the SR at either site versus Fsw, and the SR values at a given Fsw were similar between before and after heat acclimation. These findings suggest that short-term heat acclimation modulates central sudomotor mechanisms, decreasing the temperature threshold for sweating. We did not find a significant change in the peripheral mechanism for sweating by the heat acclimation program.