Chip-based photonic radar for high-resolution imaging

Radar is the only sensor that can realize target imaging at all time and all weather, which would be a key technical enabler for future intelligent society. Poor resolution and large size are two critical issues for radars to gain ground in civil applications. Conventional electronic radars are difficult to address both issues especially in the relatively low-frequency band. In this work, we propose and experimentally demonstrate, for the first time to the best of our knowledge, a chip-based photonic radar based on silicon photonic platform, which can implement high resolution imaging with very small footprint. Both the wideband signal generator and the de-chirp receiver are integrated on the chip. A broadband photonic imaging radar occupying the full Ku band is experimentally established. A high precision range measurement with a resolution of 2.7 cm and an error of less than 2.75 mm is obtained. Inverse synthetic aperture (ISAR) imaging of multiple targets with complex profiles are also implemented.Comment: 4 pages, 6figure

Risk factors of acute ischemic stroke and the role of angiotensin I in predicting prognosis of patients undergoing endovascular thrombectomy

PurposeThe interaction between the renin-angiotensin system (RAS) and the acute ischemic stroke (AIS) is definite but not fully understood. This study aimed to analyze the risk factors of AIS and explore the role of serum indicators such as angiotensin I (Ang I) in the prognosis of patients undergoing endovascular thrombectomy (EVT).Patients and methodsPatients with AIS who underwent EVT and healthy controls were retrospectively enrolled in this study, and the patients were divided into a good or a poor prognosis group. We compared Ang I, blood routine indexes, biochemical indexes, electrolyte indexes, and coagulation indexes between patients and controls. We used univariate and multivariate logistic regression analyses to evaluate possible risk factors for AIS and the prognosis of patients undergoing EVT. Independent risk factors for the prognosis of patients undergoing EVT were identified through multifactorial logistic regression analyses to construct diagnostic nomograms, further assessed by receiver operating characteristic curves (ROC).ResultsConsistent with previous studies, advanced age, high blood glucose, high D-dimer, and high prothrombin activity are risk factors for AIS. In addition, Ang I levels are lower in AIS compared to the controls. The level of Ang I was higher in the good prognosis group. Furthermore, we developed a nomogram to evaluate its ability to predict the prognosis of AIS after EVT. The AUC value of the combined ROC model (Ang I and albumin-globulin ratio (AGR)) was 0.859.ConclusionsIn conclusion, advanced age, high blood glucose, high D-dimer, and high prothrombin activity are risk factors for AIS. The combined Ang I and AGR model has a good predictive ability for the prognosis of AIS patients undergoing arterial thrombectomy

Regional metabolic patterns of abnormal postoperative behavioral performance in aged mice assessed by 1H-NMR dynamic mapping method

Abstract Abnormal postoperative neurobehavioral performance (APNP) is a common phenomenon in the early postoperative period. The disturbed homeostatic status of metabolites in the brain after anesthesia and surgery might make a significant contribution to APNP. The dynamic changes of metabolites in different brain regions after anesthesia and surgery, as well as their potential association with APNP are still not well understood. Here, we used a battery of behavioral tests to assess the effects of laparotomy under isoflurane anesthesia in aged mice, and investigated the metabolites in 12 different sub-regions of the brain at different time points using proton nuclear magnetic resonance (1H-NMR) spectroscopy. The abnormal neurobehavioral performance occurred at 6 h and/or 9 h, and recovered at 24 h after anesthesia/surgery. Compared with the control group, the altered metabolite of the model group at 6 h was aspartate (Asp), and the difference was mainly displayed in the cortex; while significant changes at 9 h occurred predominantly in the cortex and hippocampus, and the corresponding metabolites were Asp and glutamate (Glu). All changes returned to baseline at 24 h. The altered metabolic changes could have occurred as a result of the acute APNP, and the metabolites Asp and Glu in the cortex and hippocampus could provide preliminary evidence for understanding the APNP process

Prognosis of boron deficiency in oilseed rape (Brassica napus) by plant analysis

In areas where soils are low in boron (B), the ability to predict B deficiency by plant analysis depends on the development of calibrated standards and offers the potential of preventing or minimising losses in seed yield. The present study aimed at establishing relationships between seed yield in winter oilseed rape (Brassica napus) and B concentrations in defined leaves during growth before fiowering and from them to determine critical values for the prognosis of B deficiency. Oilseed rape cv. Zheyouyou 2 was grown in 10 field experiments in Zhejiang province, south-east China, with B rates from 0 to 3· 3 kg/ha. At 4 of the sites, oilseed rape was resown in the following year to assess seasonal effects on critical concentrations. Experiments were conducted on the 3 main soil groups on which oilseed rape is grown in south-east China. The youngest open leaf (YOL) was selected as the sampling part because its B concentrations were strongly responsive to increasing B supply and well correlated with seed yield response. In this study, the best model of the relationship between YOL B concentration and yield was the Mitscherlich equation, which explained 68-89% of the variation in the data. The calculated critical range in the YOL at seedling stage was 20-25 mg B/kg and appeared to be valid in 2 seasons and on 3 soil types. The critical B range for prognosis of B deficiency was found to predict consistently those crops in farmers" fields that had low seed yield and low soil B, but needs to be evaluated in other growing environments especially those for spring rape

Risk Factors of Cerebral Infarction and Myocardial Infarction after Carotid Endarterectomy Analyzed by Machine Learning

Objective. The incidence of cerebral infarction and myocardial infarction is higher in patients with carotid endarterectomy (CEA). Based on the concept of coprotection of heart and brain, this study attempts to screen the related factors of early cerebral infarction and myocardial infarction after CEA with the method of machine learning to provide clinical data for the prevention of postoperative cerebral infarction and myocardial infarction. Methods. 443 patients who received CEA operation under general anesthesia within 2 years were collected as the research objects. The demographic data, previous medical history, degree of neck vascular stenosis, blood pressure at all time points during the perioperative period, the time of occlusion, whether to place the shunt, and the time of hospital stay, whether to have cerebral infarction and myocardial infarction were collected. The machine learning model was established, and stable variables were selected based on single-factor analysis. Results. The incidence of cerebral infarction was 1.4% (6/443) and that of myocardial infarction was 2.3% (10/443). The hospitalization time of patients with cerebral infarction and myocardial infarction was longer than that of the control group (8 (7, 15) days vs. 7 (5, 8) days, P=0.002). The stable related factors were screened out by the xgboost model. The importance score (F score) was as follows: average arterial pressure during occlusion was 222 points, body mass index was 159 points, average arterial pressure postoperation was 156 points, the standard deviation of systolic pressure during occlusion was 153 points, diastolic pressure during occlusion was 146 points, mean arterial pressure after entry was 143 points, systolic pressure during occlusion was 121 points, and age was 117 points. Conclusion. Eight factors, such as blood pressure, body mass index, and age, may be related to the postoperative cerebral infarction and myocardial infarction in patients with CEA. The machine learning method deserves further study

COVID-19-related stressors and depression in Chinese adolescents: The effects of life history strategies and gender.

PURPOSE: The COVID-19 pandemic has changed the way people live, affecting both their physical and mental health. Adolescents are vulnerable to the stress of the pandemic, and may experience indicators of psychological distress, such as depression. This study aimed to examine the impact of COVID-19-related stressors on depression and the mediating role of life history strategies. METHODS: A two-wave longitudinal study was conducted with 1123 adolescents (51.20% girls, Mage = 14.30) recruited from three junior high schools in the Northeastern province of China. Adolescents life history strategies, depressive symptoms, and demographic variables were assessed at Time 1 (November 2019) and Time 2 (August 2020), and adolescents experience of COVID-19-related stressors was assessed at Time 2. None of participants was infected by COVID-19 virus. RESULTS: COVID-19-related stressors were positively associated with depressive symptoms at Time 2 (β = 0.08, p < 0.01), after controlling for gender, age, SES and depressive symptoms at Time 1. And life history strategies partially mediated the relation of pandemic stress to depression (indirect effect = 0.02, p < 0.05, 95% CI [0.004, 0.034]). There were no gender differences in the relations between stress on depression. LIMITATIONS: The sample was from a district where the pandemic was not very severe, which may limit generalizability of the results. CONCLUSIONS: This study revealed that COVID-19-related stressors may have a long-term impact on adolescents, increasing depression through speeding up their life history strategies. Interventions should focus on life history strategies, particularly cognitive style, among adolescents during and after the pandemic

Rapamycin Affects the Hippocampal SNARE Complex to Alleviate Cognitive Dysfunction Induced by Surgery in Aged Rats

Delayed neurocognitive recovery (dNCR) is a common complication that occurs post-surgery, especially in elderly individuals. The soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex plays an essential role in various membrane fusion events, such as synaptic vesicle exocytosis and autophagosome–lysosome fusion. Although SNARE complex dysfunction has been observed in several neurodegenerative disorders, the causal link between SNARE-mediated membrane fusion and dNCR remains unclear. We previously demonstrated that surgical stimuli caused cognitive impairment in aged rats by inducing α-synuclein accumulation, inhibiting autophagy, and disrupting neurotransmitter release in hippocampal synaptosomes. Here, we evaluated the effects of propofol anesthesia plus surgery on learning and memory and investigated levels of SNARE proteins and chaperones in hippocampal synaptosomes. Aged rats that received propofol anesthesia and surgery exhibited learning and memory impairments in a Morris water maze test and decreased levels of synaptosome-associated protein 25, synaptobrevin/vesicle-associated membrane protein 2, and syntaxin 1. Levels of SNARE chaperones, including mammalian uncoordinated-18, complexins 1 and 2, cysteine string protein-α, and N-ethylmaleimide-sensitive factor, were all significantly decreased following anesthesia with surgical stress. However, the synaptic vesicle marker synaptophysin was unaffected. The autophagy-enhancer rapamycin attenuated structural and functional disturbances of the SNARE complex and ameliorated disrupted neurotransmitter release. Our results indicate that perturbations of SNARE proteins in hippocampal synaptosomes may underlie the occurrence of dNCR. Moreover, the protective effect of rapamycin may partially occur through recovery of SNARE structural and functional abnormalities. Our findings provide insight into the molecular mechanisms underlying dNCR