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Aims The head‐up tilt test (HUTT) has been markedly changed over the years, especially in the specified time for the passive and active phases. However, a consensus‐based protocol has yet to be established. Methods Seven hundred twenty‐four patients suspected of vasovagal syncope who underwent HUTT through one of the protocols of 15to 20‐min testing for each active/passive phase (the whole test duration was 30 or 40 min, respectively) were evaluated. Then, the positive responses were recorded. Results 470 (64.9%) and 254 (35.1%) patients in the 15‐ and 20‐min groups, respectively. Overall, 238 patients (50.6%) in the 15‐min group and 140 patients (55.1%) in the 20‐min group had positive responses (p = 0.25). There was no significant difference in the number of positive responses between the 15‐ and 20‐min groups in any of the passive (p = 0.53) and active (p = 0.3) phases. Conclusion The 15‐min HUTT protocol has similar results to the 20‐min protocol. Saving 10 min for each test has several potential benefits, such as increasing patient acceptance, decreasing patient discomfort, and enabling the conduct of more tests in a day in a syncope unit. In patients with suspected vasovagal syncope, a 15‐min head‐up tilt test protocol yielded similar diagnostic results to the conventional 20‐min protocol. This shorter approach may improve patient comfort and syncope unit efficiency without compromising diagnostic accuracy.

Objective Postoperative progressive coronal caudal curve (PCC) was characterized by a postoperative de novo caudal S -curve ≥ 20° following congenital cervicothoracic scoliosis (CTS) corrective osteotomies, and at least 20° greater than the preoperative measurement, while the incidence was uncertain and the pathogenesis was equivocal. The objective of this study was to investigate the morbidity and potential factors contributing to PCC following CTS surgery. Methods This study reviewed 72 CTS patients between 2005 and 2021. Patients were categorized into two groups according to the absence or presence of PCC at last follow-up, namely the nonprogressive curve group (NPC-group) and the progressive curve group (PC-group). Demographics, radiographic data and the Scoliosis Research Society-22 (SRS-22) questionnaire results were reviewed. Multivariate linear regression analyses were utilized to determine possible predictors for PCC. Results PCC was observed in 11 (15%) of the total 72 patients. Compared with the NPC-group, the PC-group exhibited greater postoperative residual local curve (24.0 ± 9.7° vs. 9.1 ± 4.4°, P  < 0.001), upper instrumented vertebra (UIV) tilt (16.9 ± 7.4° vs. 6.2 ± 3.7°, P  < 0.001), T1 tilt (14.3 ± 9.4° vs. 6.6 ± 3.9°, P  = 0.022) and neck tilt (10.1 ± 6.7° vs. 3.7 ± 2.5, P  = 0.009). The multivariable linear regression demonstrated that the larger postoperative UIV tilt, residual local curve and neck tilt were associated with PCC. In addition, patients with PCC showed lower SRS-22 scores in terms of pain, mental health, self-image and satisfaction ( P  < 0.05). Conclusions The morbidity of PCC was 15% in CTS patients who underwent corrective osteotomies. Greater residual local curve, postoperative UIV tilt and neck tilt were identified as predictors for PCC.

Purpose This paper aims to address shortcomings of current tiltrotor designs, such as the small aspect ratio of the wings, large download and the close proximity of the rotor tips. It also aims to avoid the complex transition of tiltrotors to normal airplane mode. Design/methodology/approach This design combines tiltrotor and tiltwing aircraft designs into a hybrid that is augmented by active flow control, using a gimbaled channel wing for attitude control in hover. Findings The proposed hybrid design is based on experimental results of components that were tested individually for potential use in hover and steep ascend from a stationary position. Originality/value This research was inspired by the extremely short take-off of the V-22, when its rotors were tilted forward. It combines several design approaches in a unique way to achieve extremely short take-off capabilities combined with high-speed and reduced maintenance costs.

The mild activity of basaltic volcanoes is punctuated by violent explosive eruptions that occur without obvious precursors. Modelling the source processes of these sudden blasts is challenging. Here, we use two decades of ground deformation (tilt) records from Stromboli volcano to shed light, with unprecedented detail, on the short-term (minute-scale) conduit processes that drive such violent volcanic eruptions. We find that explosive eruptions, with source parameters spanning seven orders of magnitude, all share a common pre-blast ground inflation trend. We explain this exponential inflation using a model in which pressure build-up is caused by the rapid expansion of volatile-rich magma rising from depth into a shallow (<400 m) resident magma conduit. We show that the duration and amplitude of this inflation trend scales with the eruption magnitude, indicating that the explosive dynamics obey the same (scale-invariant) conduit process. This scale-invariance of pre-explosion ground deformation may usher in a new era of short-term eruption forecasting. Here, the authors use 20 years of ground deformation data from Stromboli and correlate this data with eruptive records. They find that duration and amplitude of the inflation trend scales with eruption magnitude, indicating that explosive dynamics obeys the same (scale-invariant) conduit process.

Postural fluid shifts may directly affect respiratory control via a complex interaction of baro‐ and chemo‐reflexes, and cerebral blood flow. Few data exist concerning the steady state ventilatory responses during head‐down tilt. We examined the cardiorespiratory responses during acute 50° head‐down tilt (HDT) in 18 healthy subjects (mean [SD] age 27 [10] years). Protocol 1 (n = 8, two female) was 50° HDT from 60° head‐up posture sustained for 10 min, while exposed to normoxia, normoxic hypercapnia (5% CO2), hypoxia (12% inspired O2) or hyperoxic hypercapnia (95% O2, 5% CO2). Protocol 2 (n = 10, four female) was 50° HDT from supine, sustained for 10 min, while breathing either medical air or normoxic hypercapnic (5% CO2) gas. Ventilation (V̇E ${{\\dot{V}}_E}$ , pneumotachograph), end‐tidal O2 and CO2 concentration and blood pressure (Finapres) were measured continuously throughout each protocol. Middle cerebral artery blood flow velocity (MCAv; transcranial Doppler) was also measured during protocol 2. Ventilation increased significantly (P < 0.05) compared to baseline during HDT in both hyperoxic hypercapnia (protocol 1 by mean [SD] 139 [26]%) and normoxic hypercapnia (protocol 1 by mean [SD] 131 [21]% and protocol 2 by 129 [23]%), despite no change in PETCO2 ${{P}_{{\\mathrm{ETC}}{{{\\mathrm{O}}}_2}}}$or PETO2 ${{P}_{{\\mathrm{ET}}{{{\\mathrm{O}}}_2}}}$from baseline. No change in V̇E ${{\\dot{V}}_E}$was observed during HDT with medical air or hypoxia, and there was no significant change in MCAv during HDT compared to baseline. The absence of change in cerebral blood flow leads us to postulate that the augmented ventilatory response during steep HDT may involve mechanisms related to cerebral venous pressure and venous outflow. What is the central question of this study? Postural fluid shifts affect respiratory control via complex interactions between baroreceptor and chemoreceptor reflexes, and cerebral blood flow. Few data exist concerning steady state ventilatory responses during head down tilt. What is the main finding and its importance? Acute 50° head‐down tilt augments the ventilatory response to steady state normoxic and hyperoxic hypercapnia possibly via mechanisms involving cerebral blood flow. These findings are relevant clinically during procedures performed in a steep head‐down position and microgravity environments where individuals are exposed to fluid shifts and elevated atmospheric CO2.

This paper focuses on the safety of ribbon bridge navigation at different flow speeds, including bow tilt and stern tilt. By constructing a CAD 3 dimensions simulation model and CFD simulation test model of a ribbon bridge, the Hydrodynamics of the ribbon bridge under different load conditions and flow velocity is simulated and calculated based on the GMRES algorithm.The environmental adaptability assessment was carried out from the aspects of bow tilt, stern tilt and flow velocity adaptability of the ribbon bridge, and the navigation safety and stability of the ribbon bridge in different environments were obtained, which could provide data reference and support for the safe navigation of the ribbon bridge in the actual waters.

PurposeThe aim is to propose a novel spinopelvic parameter C7 sacral tilt (C7ST), of which its sum with global tilt (GT) is equal to pelvic incidence (PI), from a geometrical point of view.MethodsA cohort of 198 patients was recruited and the whole lateral spine and pelvic radiographs were performed. The following sagittal parameters were measured: sagittal vertical axis (SVA), C7 vertical tilt (C7VT), sacral slope (SS), pelvic tilt (PT), PI, GT and C7ST. The correlations between them were analyzed using the Pearson or Spearman correlation coefficient, and simple linear regressions were simultaneously conducted. P < 0.05 was set as the level of significance.ResultsGeometric construction by complementary angles revealed that PI = C7ST + GT, GT = PT + C7VT, and C7ST = SS − C7VT. Both C7ST and GT were moderately correlated with PI (R = 0.52 and 0.596, respectively), strongly correlated with SS and PT, respectively (SS = 0.9 * C7ST + 1.15, R = 0.955; PT = 0.87 * GT + 3.86, R = 0.96). The correlation coefficients of the SVA and C7VT, SVA and SS − C7ST, and SVA and GT − PT were 0.935, 0.925 and 0.863, respectively.ConclusionThe novel proposed spinopelvic parameter C7ST has the advantages of convenient measurement, reduced error, and extrapolation of other parameters. The greatest significance of proposing C7ST is that pelvic parameters (PI, PT and SS) are converted into spinal parameters (C7ST and GT), which is very helpful for a more intuitive understanding of the progression of spinal sagittal imbalance.

Low-frequency seismic vibrations extremely limit the performance of ground simulation facilities for space-borne gravitational wave detections, which need to be substantially suppressed. Active vibration systems are thus required. However, the tilt-translation coupling of inertial sensors strongly limits the performance of vibration isolation platforms in the low frequency range, which requires a precise measurement of the low-frequency tilt signal. This study compares two methods for the tilt signal measurement: the differential-mode method and the direct method. The differential-mode method estimates tilt signals by analyzing differential motion between two inertial sensors, while the direct method utilizes an interferometric tilt sensor (ITS) which consists of a suspended rotational beam system and an interferometer for the readout. Experimental results show that ITS achieves a lower noise floor. Its noise floor is dominated by the thermal-mechanical noise below 0.25 Hz and the readout noise of the interferometer above 0.25 Hz. The findings highlight the potential of ITS for improving the performance of vibration isolation platforms in the low-frequency range.

Background Neurally mediated syncope (NMS) is the primary cause of temporary and self‐limiting loss of consciousness. The tilt table test (TTT) has been consistently employed as a supplementary diagnostic tool for syncope evaluation. However, TTT requires specialized equipment, which is lacking in several emergency room and clinic environments. We hypothesized that patients susceptible to NMS may have higher parasympathetic tone. Thus, this study investigates the correlation between PR interval and Herat rate variability parameters as indicators of parasympathetic tone and TTT results. Methods We included 213 patients referred to our cardiology clinic with an impression of NMS in 2022 and 2023. Data was retrospectively collected from 24‐h ambulatory electrocardiographic monitoring recordings, TTT results, and patients' history and physical examination records. Results The analysis of the PR interval revealed a mean duration of 155 ms (95% CI: 148.61, 161.39) in negative TTT patients and 164.21 ms (95% CI: 158.44, 169.97) in positive TTT patients, indicating a statistically significant difference between two groups (p = 0.035). We also found that patients with a PR interval duration exceeding 160 ms demonstrated a significantly higher prevalence of positive TTT compared to those with a PR interval duration of less than 160 ms (p < 0.001, OR: 3.911, 95% CI: 2.143, 7.140). Conclusions Our study suggests a PR interval longer than 160 milliseconds as a valuable tool for predicting TTT results and identifying patients at higher risk of NMS. A longer PR interval correlates with a positive tilt table test. This suggests that an AEM‐derived PR interval duration longer than 160 ms may be a valuable tool for predicting TTT results and identifying patients at higher risk of NMS.

Undetected actuator faults on tilt tri‐rotor UAVs can lead to system failures and uncontrolled crashes. Multiple flight modes result in complex models with strong nonlinearity, making fault detection of their actuators a very challenging task. To address this issue, this article proposes a fault detection method based on residual generated by using TSK fuzzy model. Initially, the flight modes of the tilt tri‐rotor UAV are modeled as the TSK fuzzy model. Following this, the residual generator is employed for rapid detection of actuator failures. To enhance detection accuracy, the kernel principal component analysis (KPCA) algorithm is used for a secondary confirmation. The proposed algorithm was validated using both a simulation platform and real flight data. The results demonstrate that the fault detection algorithm achieves high accuracy and real‐time performance, with a computing time of approximately 41 ms in real controller hardware, thus meeting the requirements of practical applications. This article proposes a residual‐based fault detection algorithm to address actuator failures in tilt tri‐rotor UAVs. Using the TSK fuzzy model and kernel principal component analysis (KPCA) for enhanced accuracy, the method is validated through simulations and real flight data, achieving high accuracy and real‐time performance with a response time of approximately 41 ms.