Binning method for artifact-free time-tag based correlation function calculations.

Correlation functions are nowadays routinely computed using time-tagged photon information instead of a hardware autocorrelator. The algorithm developed by Laurence et al. [Opt. Lett.31, 829 (2006)10.1364/OL.31.000829] is a powerful example. Despite its ease of implementation and fast computation process, it presents a prevalent noisy feature at the short time-lag range when computed on commonly used logarithmically spaced bins. We identified that arbitral logarithmic spacing produces the mismatch between the edges of generated bins and acquisition frequency, resulting in an aliasing artifact at the short time-lag range of the correlation function. We introduce a binning method that considers the acquisition frequency during the bin generation. It effectively eliminates the artifact and improves the accuracy of the autocorrelation. Applying the binning method herein can be particularly crucial when one extracts photophysical processes from fluorescence correlation spectroscopy or the diffusion coefficient of nanoparticles from dynamic light scattering at the time range below 10-5 s lag time.

Association between preoperative phase angle and all-cause mortality after cardiovascular surgery: A retrospective cohort study.

BACKGROUND: The importance of preoperative physical function assessment for post-operative intervention has been reported in older patients undergoing cardiovascular surgery. Phase angle (PhA), measured using bioelectrical impedance analysis, is an indicator of cellular health and integrity and is reported as a prognostic factor in several chronic diseases; however, its association with the long-term prognosis of cardiovascular surgery remains unclear. This study aimed to investigate the prognostic value of PhA for long-term mortality in patients undergoing cardiovascular surgery. METHODS: This retrospective cohort study included consecutive patients who underwent elective cardiovascular surgery between October 2016 and March 2021 at Nagoya Heart Center, Japan. PhA was assessed using bioelectrical impedance analysis before surgery, and physical function measures (gait speed, grip strength and short physical performance battery [SPPB]) were measured synchronously. The association between PhA and all-cause mortality after discharge was assessed using Kaplan-Meier and multivariate Cox regression analyses. The incremental prognostic value of PhA was compared with other physical function measures using net reclassification improvement (NRI) and integrated discrimination improvement (IDI). RESULTS: A total of 858 patients were included in the present analysis (mean age = 68.4 ± 11.9 years, 67.6% male). PhA positively correlated with body mass index (ρ = 0.38, P < 0.001), skeletal muscle mass index (ρ = 0.58, P < 0.001), usual gait speed (ρ = 0.44, P < 0.001), grip strength (ρ = 0.73, P < 0.001) and SPPB (ρ = 0.51, P < 0.001). The mean follow-up period, within which 44 (4.7%) died, was 908.9 ± 499.9 days for the entire cohort. Kaplan-Meier survival curves based on the PhA tertiles showed that higher PhA was associated with better survival (log-rank test, P < 0.001). The Cox regression analysis showed the independent association of PhA with mortality risk (hazard ratio: 0.91 per 0.1° increment; 95% confidence interval [CI]: 0.87-0.95; P < 0.001). The NRI and IDI showed significant improvements in predicting mortality after adding PhA to the clinical model consisting of age, sex and cardiac and renal function (NRI: 0.426, 95% CI: 0.124-0.729, P = 0.006; IDI: 0.037, 95% CI: 0.012-0.062, P = 0.003). The predictive model consisting of the clinical model and PhA was superior to the model consisting of the clinical model and each of the other physical function indicators (P < 0.05). CONCLUSIONS: PhA correlated with physical function and independently predicted long-term mortality after cardiovascular surgery. The additive prognostic value of PhA compared with the other physical function measures suggests the clinical usefulness of preoperative PhA for risk stratification in planning post-operative treatment and rehabilitation.

Association of Nutritional Risk With Gait Function and Activities of Daily Living in Older Adult Patients With Hip Fractures.

OBJECTIVE: To investigate the association of nutritional risk with gait function and activities of daily living (ADLs) in older adult patients with hip fractures. METHODS: The retrospective data of older adult patients diagnosed with hip fractures who visited the recovery-phase rehabilitation ward between January 2019 and December 2022 were reviewed. Nutritional risk was evaluated using the Geriatric Nutritional Risk Index; gait function and ADLs were assessed using the modified Harris Hip Score subitem and Functional Independence Measure, respectively. Multivariate linear regression and path analysis with structural equation modeling were used to examine the factors associated with ADLs and the associations among the study variables. RESULTS: This study included 206 participants (172 females and 34 males; mean age, 85.0±7.3 years). In the multivariate analysis, gait function (ß=0.488, p<0.001), cognitive function (ß=0.430, p<0.001), and surgery (ß=-0.143, p<0.001) were identified as independent factors. Pathway analysis revealed that nutritional risk was not directly correlated with ADLs but was directly associated with gait and cognitive functions. Gait and cognitive functions, in turn, were directly related to ADLs. CONCLUSION: Nutritional risk was found to be associated with ADLs through an intermediary of gait and cognitive functions.

In situ/In vivo Optical Microspectroscopy to Probe the Emergence of Morphology.

Morphology governs function. Yet, understanding and controlling the emergence of morphology at the molecular level remains challenging. The difficulty in studying the early stage of morphology formation is due to its stochastic nature both spatially and temporally occurring at the nanoscale. This nature has been particularly detrimental for the application of optical spectroscopy. To overcome this problem, we have been developing new in situ/in vivo optical spectroscopy tools, which are label-free and non-invasive. This account highlights several examples of how optical spectroscopy can become an important tool in studying the birth of morphology.

Changes in walking speed 6 months after discharge may be more sensitive to subsequent prognosis than handgrip strength in patients hospitalized for heart failure.

BACKGROUND: Despite the prognostic importance of walking speed (WS) and handgrip strength (HGS) in patients with heart failure (HF), no study has reported the prognostic impact of changes in these parameters. This study aimed to examine the association between changes after discharge and the subsequent prognosis. METHODS: This study included 881 elderly patients hospitalized for HF. WS and HGS were measured at discharge and 6 months after discharge. Based on the presence of slowness (WS <0.98 m/s) or weakness (HGS <30.0 kg for men and < 17.5 kg for women) at both points, patients were divided into four groups (WS: A = -/-, B = -/+, C = +/-, D = +/+; HGS: E = -/-, F = -/+, G = +/-, H = +/+). The study endpoint was a composite of all-cause mortality and HF rehospitalization during the 18 months after 6 months of discharge. The Cox proportional hazards model was used to assess the association between the groups and study outcomes. RESULTS: Stratified by the WS change patterns, groups B and D showed higher risk of the study outcomes than group A [B: hazard ratio 2.34, 95% confidence interval (CI) 1.29-4.28; D: 2.38, 1.67-3.39], whereas group C was not. When stratified by the HGS change in patterns, only group H was associated with a worse prognosis (HR; 1.85, 95%CI; 1.31-2.60). CONCLUSION: Changes in WS were related to HF prognosis, suggesting that changes in WS may be more sensitive to further risk stratification than changes in HGS.

Questionnaire-based scoring system for screening moderate-to-vigorous physical activity in middle-aged Japanese workers.

OBJECTIVES: Currently available questionnaires have limited ability to measure physical activity (PA) using accelerometers as a gold standard. This study aimed to develop a PA questionnaire for middle-aged Japanese workers and propose a PA scoring system for predicting low moderate-to-vigorous PA (MVPA). METHODS: A total of 428 participants (median age 49 years; 75.8% men) participated in a 7-day PA measurement using an accelerometer and a questionnaire. The association between questionnaire responses and low MVPA (<150 min/wk) was assessed by logistic regression analysis. A score was assigned to each response based on the correlation coefficients of the multivariate model. The ability of the sum score to predict low MVPA was assessed using the area under the receiver operating characteristic curve (AUC). RESULTS: Five questionnaire items were used for measuring PA scores (range: 0-50; higher scores indicated a higher probability of low MVPA). The AUC was 0.741 (95% CI, 0.689-0.792), and the sensitivity and specificity at the optimal cut-off value were 66.7% and 68.2%, respectively. This predictive ability was slightly increased by body mass index (AUC 0.745 [95% CI, 0.693-0.796]; sensitivity 69.9%; specificity 66.9%). These predictive values were greater than those of conventional questionnaires used in health checkups in Japan (P < .05). CONCLUSIONS: This questionnaire-based PA scoring system showed moderate accuracy in predicting low MVPA. It is useful for screening physically inactive workers and promoting PA.