Insulin Resistance-Varying Associations of Adiposity Indices with Cerebral Perfusion in Older Adults: A Population-Based Study.

OBJECTIVES: Excessive accumulation of adipose tissue may accelerate brain aging, but the underlying mechanisms are poorly understood. Several adiposity indices were proposed to assess obesity, while their linkage with brain health in older adults remained unclear. Here we aimed to examine the associations of adiposity indices with global and regional cerebral blood flow (CBF) in older adults, while considering insulin resistance. DESIGN: This was a cross-sectional population-based study that included older adults derived from the baseline participants in the ongoing Multimodal Interventions to Delay Dementia and Disability in rural China (MIND-China) study. SETTING AND PARTICIPANTS: The study included 103 Chinese rural-dwelling older adults (age≥60 years; 69.9% women) who underwent brain magnetic resonance imaging scans. METHODS: We estimated eight adiposity indices based on anthropometric measures. We automatically quantified global and regional CBF using the arterial spin labeling scans. Insulin resistance was assessed using the triglyceride-glucose index and then dichotomized into high and low levels according to the median. Data were analyzed using general linear model and voxel-wise analysis. RESULTS: Of the eight examined adiposity indices, only higher waist-to-height ratio (WHtR) and body roundness index (BRI) were associated with reduced global CBF (multivariable-adjusted ß-coefficients and 95%CI: -1.76; -3.25, -0.27 and -1.77; -3.25, -0.30, respectively) and hypoperfusion in bilateral middle temporal gyri, angular gyri and superior temporal gyri, left middle cingulum and precuneus (P<0.05). There were statistical interactions of WHtR and BRI with levels of insulin resistance on CBF, such that the significant associations of higher WHtR and BRI with lower global and regional CBF existed only in people with high insulin resistance (P<0.05). CONCLUSION: Higher WHtR and BRI are associated with cerebral hypoperfusion in older adults, especially in people with high insulin resistance. This may highlight the pathological role of visceral fat in vascular brain aging.

[Clinical characteristics of coal worker's peneumoconiosis complicated with acute exacerbation of chronic obstractive pulno-mary disease].

Objective: To investigate the clinical characteristics of acute exacerbation of acute lung disease (AECOPD) and to provide reference for clinical diagnosis and treatment. Methods: From January 2018 to December 2018, 127 patients with AECOPD were investigated retrospectively in March 2020, including 65 cases of pneumoconiosis with AECOPD group, 62 cases of AECOPD group, 127 cases of AECOPD group, the clinical characteristics, length of stay, cost difference and the correlation between pulmonary function and blood gas were analyzed in patients with AECOPD. Results: There was no significant difference in age, height, weight, BMI, ethnicity and smoking between the two groups (P>0.05) . The percentage of Neutrophil and hs-crp in pneumoconiosis combined with AECOPD group were significantly higher than those in AECOPD group (P<0.05) . The oxygen partial pressure in pneumoconiosis combined AECOPD group was lower than that in control group (P<0.05) . VC, FVC/Pred%, FEV(1)/Pred% in pneumoconiosis combined with AECOPD group were lower than those in AECOPD group, RV/Pred% and RV/TLC were higher than those in AECOPD group (P<0.05) . The hospitalization time and cost of the patients with AECOPD were significantly higher than that of the patients with AECOPD (P<0.05) . Conclusion: Compared with AECOPD group, the patients with pneumoconiosis combined AECOPD group had higher infection inflammation level, lower pulmonary function, longer hospitalization time and higher hospitalization cost.

Maximizing the security of chaotic optical communications.

The practical application of chaotic optical communications has been limited by two aspects: the difficulty in concealing the time delay - a critical security parameter in feedback chaotic systems, and the difficulty of significantly enlarging the key space without complicating the implementation. Here we propose an architecture to break the above limits. By introducing a frequency-dependent group delay module with frequency tuning resolution of 1 MHz into the chaotic feedback loop, we demonstrate excellent time delay concealment effect, and an additional huge key space of 1048 can be achieved at the same time. The effectiveness is proved by both numerical simulation and experiment. Besides, the proposed scheme is compatible with the existing commercial optical communication systems, thus pave the way for high-speed secure optical communications.

Estrogen-like activities in Vitex species from China determined by a cell based proliferation assay.

Ethanolic extracts of four Chinese medicinally used Vitex species were selected and tested for their estrogen-like activities, using an ERalpha-positive MCF-7 cell based proliferation assay (E-screen assay) and cell cycle analysis (flow cytometry). Vitex negundo displayed the highest estrogenic-like activity, and could be useful in hormone replacement therapy (HRT).

Role of parvalbumin in relaxation of frog skeletal muscle.

Experiments were done to test the hypothesis that parvalbumin (PA) promotes relaxation in frog skeletal muscle. Single fibers and purified PA from R. temporaria skeletal muscle were used to determine the relationship between Ca2+ and Mg2+ dissociation rates from PA and changes in relaxation rate as a function of isometric tetanus duration at 0 degrees C. Relaxation rate slows as a function of tetanus duration with a rate constant of 1.18 s-1. Recovery of relaxation rate after a prolonged tetanus exhibits a rate constant of 0.12 s-1. Dissociation rate constants for Mg2+ and Ca2+ from purified PA are 0.93 s-1 and 0.19 s-1, respectively. Thus rates of slowing and recovery of relaxation rate may be controlled by Mg2+ and Ca2+ dissociation from PA, respectively. The influence of temperature on relaxation rate and on Ca2+ and Mg2+ dissociation rates from purified PA also was examined. The magnitude of slowing of relaxation rate with increasing tetanus duration, relative to the final, steady value of relaxation rate, is greater at 0 than at 10 degrees C. In the 0 to 10 degrees C range, the Q10 for relaxation rate increases with increasing tetanus duration. Both of these observations can be explained if the Q10 for Ca2+ uptake by the sarcoplasmic reticulum is greater than the Q10 for Ca2+ sequestration by PA during relaxation. When Ca2+ and Mg2+ dissociation rates from PA at various temperatures are compared to other proposed indicators of PA function, it is concluded that PA facilitates relaxation of frog skeletal muscle in the 0 to 20 degrees C range.

Effect of temperature on relaxation rate and Ca2+, Mg2+ dissociation rates from parvalbumin of frog muscle fibres.

1. Influence of temperature on relaxation rate as a function of isometric tetanus duration and on Ca2+ and Mg2+ dissociation rates from purified parvalbumin (PA) was examined to test the hypothesis that PA promotes relaxation in frog skeletal muscle. Single fibres and PA IVB from Rana temporaria skeletal muscle were utilized. 2. The magnitude of slowing of relaxation rate with increasing tetanus duration, relative to the final, steady value of relaxation rate, is 3-fold greater at O than at 10 degrees C. 3. In the 0-10 degrees C range, the Q10 for relaxation rate increases from 2.3 to 3.7 with increasing tetanus duration. 4. Dissociation of Ca2+ and Mg2+ from PA exhibited: (i) rate constants of 1.03 +/- 0.03 s-1 (mean +/- S.D., n = 5) and 3.42 +/- 0.14 s-1 (n = 5) at 20 degrees C and (ii) Q10 values of 2.3 and 1.9 in the 0-20 degrees C range, respectively. 5. Time courses of slowing of relaxation rate with increasing tetanus duration and recovery of relaxation rate with rest after a prolonged tetanus at 10 degrees C are similar to rates of dissociation of Mg2+ and Ca2+ from PA, respectively, as previously reported at 0 degree C. 6. Both the temperature dependence of the relative magnitude of slowing of relaxation rate and the increased Q10 of relaxation rate with increased tetanus duration can be explained if the Q10 for Ca2+ uptake by the sarcoplasmic reticulum is greater than the Q10 for Ca2+ sequestration by PA during relaxation. When Ca2+ and Mg2+ dissociation rates from PA at various temperatures are compared to other proposed indicators of PA function, it is concluded that PA facilitates relaxation of frog skeletal muscle in the 0-20 degrees C range.

Parvalbumin content and Ca2+ and Mg2+ dissociation rates correlated with changes in relaxation rate of frog muscle fibres.

1. Experiments were done to test the hypothesis that parvalbumin (PA) promotes relaxation in frog skeletal muscle. Single fibres and purified PA from Rana temporaria skeletal muscle were used to determine the relationship between PA concentration ( [PA] ), Ca2+ and Mg2+ dissociation rates from PA and changes in rate of relaxation as a function of tetanus duration at 0 degrees C. 2. Total [PA] in fibres from tibialis anterior muscles is 0.76 +/- 0.20 mmol PA l-1 myoplasmic water (mean +/- S.D., n = 25) with 65% PA IVa and 35% PA IVb, where PA IVa and PA IVb are PA isoforms. 3. Relaxation rate from an isometric tetanus shows progressively as a function of tetanus duration with an exponential time course and a rate constant of 1.18 +/- 0.35 s-1 (n = 17). Time course of recovery of relaxation rate after a prolonged tetanus is exponential with a rate constant of 0.12 +/- 0.02 s-1 (n = 14). 4. The extent of recovery of relaxation rate after a prolonged tetanus was correlated with total [PA] in fibres (correlation coefficient (r) = 0.80, n = 7; P less than 0.05). 5. Dissociation rate constants for Mg2+ and Ca2+ from purified PA are 0.93 +/- 0.02 s-1 (n = 5) and 0.19 +/- 0.01 s-1 (n = 5), respectively. Dissociation rate constants were not significantly different for PA isoforms IVa and IVb. These rate constants are similar to the rate constants determined for the time courses of slowing and recovery of relaxation rate, respectively. 6. Results suggest that the time courses of slowing and recovery of relaxation rate may be controlled, to a large extent, by Mg2+ and Ca2+ dissociation from PA, respectively. This evidence supports a role for PA in facilitating relaxation during a tetanus in frog skeletal muscle at 0 degrees C.