Blood pressure-cerebral oxygen coupling model: A new approach for stroke risk prediction.

Stroke is a major cause of death and disability worldwide, but predicting its risk remains challenging. This study aimed to evaluate the cerebral blood flow autoregulation function of subjects with different stroke risk levels and predict their stroke risk. The coupling strength between cerebral oxygen and blood pressure signals was calculated by wavelet analysis and dynamic Bayesian inference and used as a quantitative index of cerebral blood flow autoregulation. A stroke prediction model based on the extreme random tree was constructed using the coupling strength and other data as input features. The results showed that the coupling strength was significantly higher in the high-risk group than the other groups. Moreover, the prediction model achieved an average accuracy of 0.80 across the three groups. The coupling strength of cerebral oxygen and blood pressure can be used as an objective index to predict stroke risk, which has implications for stroke prevention and intervention.

Identifying Cognitive Impairment in Elderly Using Coupling Functions Between Cerebral Oxyhemoglobin and Arterial Blood Pressure.

Background: This study aimed to assess brain oxygenation status and cerebral autoregulation function in subjects with cognitive dysfunction. Methods: The Montreal Cognitive Assessment (MoCA) was applied to divide the subjects into three groups: cognitive impairment (Group CI, 72.50 ± 10.93 y), mild cognitive impairment (Group MCI, 72.02 ± 9.90 y), and normal cognition (Group NC, 70.72 ± 7.66 y). Near-infrared spectroscopy technology and a non-invasive blood pressure device were used to simultaneously measure changes in cerebral tissue oxygenation signals in the bilateral prefrontal lobes (LPFC/RPFC) and arterial blood pressure (ABP) signals from subjects in the resting state (15 min). The coupling between ABP and cerebral oxyhemoglobin concentrations (Δ [O2Hb]) was calculated in very-low-frequency (VLF, 0.02-0.07 Hz) and low-frequency (LF, 0.07-0.2 Hz) bands based on the dynamical Bayesian inference approach. Pearson correlation analyses were used to study the relationships between MoCA scores, tissue oxygenation index, and strength of coupling function. Results: In the interval VLF, Group CI (p = 0.001) and Group MCI (p = 0.013) exhibited significantly higher coupling strength from ABP to Δ [O2Hb] in the LPFC than Group NC. In the interval LF, coupling strength from ABP to Δ [O2Hb] in the LPFC was significantly higher in Group CI than in Group NC (p = 0.001). Pearson correlation results showed that MoCA scores had a significant positive correlation with the tissue oxygenation index and a significant negative correlation with the coupling strength from ABP to Δ [O2Hb]. Conclusion: The significantly increased coupling strength may be evidence of impaired cerebral autoregulation function in subjects with cognitive dysfunction. The Pearson correlation results suggest that indicators of brain oxygenation status and cerebral autoregulation function can reflect cognitive function. This study provides insights into the mechanisms underlying the pathophysiology of cognitive impairment and provides objective indicators for screening cognitive impairment in the elderly population.

Effect of electroacupuncture at Zusanli (ST 36) on dorsal root nerve signals in normal rats.

OBJECTIVE: To investigate how electroacupuncture (EA) at Zusanli (ST 36) with varying intensities of stimulation affects dorsal root nerve signals in normal rats. METHODS: Adult female Wistar rats were examined after drug-induced anesthesia and isolation of the L4 dorsal root associated with the Zusanli (ST 36) acupoint, using bipolar platinum electrodes. We applied EA at Zusanli (ST 36) with a continuous wave waveform for 1 min, and recorded action potentials in the L4 spinal cord dorsal root nerve with a frequency of 5 Hz and various current intensity levels (approximately 1-4 mA). In addition, we tested EA with a frequency of 15 Hz and current intensity of 1-4 mA. The L4 spinal cord dorsal nerve bundle action potentials were measured for 1 min of EA. To analyze the discharge frequency, we used the maximum Lyapunov exponent and Lempel-Ziv (LZ) complexity. RESULTS: At a fixed frequency, with increasing intensity of EA, dorsal root nerve filament discharge frequency revealed an initial increase, followed by a decreasing trend. A stimulation intensity of 3 mA induced a significantly greater discharge frequency, compared with stimulation intensities of 2 and 4 mA. EA stimulation evoked neuroelectric signals with chaotic characteristics. Increased intensity led to an initial increase in LZ complexity which then decreased, with a stimulation strength of 3 mA inducing the highest level of LZ complexity. CONCLUSION: EA of different intensities can induce nerve action potential encoding with different features.

[Effects of the Veterinary Antibiotic Sulfamethazine on Ammonia Volatilization from a Paddy Field Treated with Conventional Synthetic Fertilizer and Manure].

Veterinary antibiotics have been widely detected in croplands due to the application of animal excrements as fertilizer. However, their effects on ammonia (NH3) volatilization remain unclear. A field experiment was conducted to evaluate the effect of sulfamethazine on NH3 volatilization from a paddy field when conventional synthetic fertilizer or manure was applied as basal fertilizer. Five different treatments were conducted in this study: without application of fertilizers and antibiotics (CK), compound fertilizer used as basal fertilizer with and without the addition of sulfamethazine (CF+SD and CF respectively), and pig manure used as base fertilizer with and without the addition of sulfamethazine (CM+SD and CM respectively). Urea was used for topdressing in the CF, CF+SD, CM, and CM+SD treatments. The results showed that regardless of the fertilizer type applied, sulfamethazine did not affect the seasonal pattern of NH3volatilization. However, it promoted the NH3 volatilization rate in the topdressing stage significantly (P<0.01). During the observation period, the proportions of applied N lost as NH3-N in the CF+SD and CM+SD treatments were 1.65 and 2.78 times higher than those in the CF and CM treatments, respectively. The promoting effect of sulfamethazine was more obvious in the pig manure treatment than in the compound fertilizer treatment. Sulfamethazine significantly increased the soil urease activity (P<0.05). Furthermore, the NH3 volatilization rate was positively correlated with urease activity and soil ammonia nitrogen content (P<0.05). This indicates that sulfamethazine can increase the NH3 volatilization rate by changing the soil urease activity and inorganic nitrogen content. Controlling the misuse of veterinary antibiotics and environmental and ecological risks posed by the antibiotic residues in farmland excrements are urgent problems in China that need to be solved.

Assessment of reactive nitrogen mitigation potential of different nitrogen treatments under direct-seeded rice and wheat cropping system.

The reactive nitrogen (Nr) pollution is a serious environmental problem. A wise application of nitrogen fertilizer is important for mitigating Nr loss. Field experiments were undertaken during the direct-seeded rice and winter-wheat growing seasons from 2014 to 2015 in Nanjing, one of the typical rice-wheat rotation regions in China, to evaluate the potential of different nitrogen fertilizers for mitigating Nr (N2O, NH3 emissions, and NO3- leaching) losses. Seven different fertilizer treatments were included in this study: a no fertilizer treatment (NF), conventional fertilizer (CF), urea-ammonium mixed nitrogen fertilizer (UA), stabilized urea (UHD; urea + hydroquinone + dicyandiamide), sulfur-coated urea (SCU), urea formaldehyde (UF) and organic fertilizer (OF). In comparison with the CF, all the fertilizer treatments except for UA decreased NH3 volatilization by 14.5-36.0% (p < 0.05), while none of the N fertilizers had an obvious mitigation effect on N2O emissions and NO3- leaching during the rice and wheat seasons. Further analyses showed that the UHD, UF and OF treatments reduced the yield-scaled Nr loss (NLI) by 32.6-42.5% for the rice season and by 15.5-34.5% for the wheat season as compared to the CF; other treatments relative to CF had no obvious effect with regard to lowering the NLI. UHD, UF and OF could be adopted as an effective mitigation alternative to reduce Nr loss and maintain crop yield in future rice/wheat production. Graphical abstract ᅟ.

[Reinforcing and reducing method of bloodletting therapy].

Through review and analysis on description of bloodletting therapy in ancient medical classics, it is found that bloodletting therapy can be classified as two categories of reinforcing and reducing. And the classification is related with many factors such as the quantity of blood, apparatus selected, depth of acupuncture, points selected and physical conditions, etc. Bloodletting therapy is not confined only in excessive syndromes, it is also applied to the treatment of complicated syndrome of excess and deficiency as well as deficiency syndrome with excessive manifestations and deficiency syndrome.