Research on an Active Hydrogen Maser Digital Circuit Control System Based on FPGA.

A hydrogen maser is a high-precision time measurement instrument with high frequency stability and low frequency drift, which is widely used in satellite navigation, ground time keeping, frequency measurement, and other fields. An active hydrogen maser (AHM) is better than the current space passive hydrogen maser (PHM) in orbit in terms of its frequency stability and drift rate, but it has the disadvantages of large volume and weight. To further reduce the volume and weight of the circuit, this paper demonstrates a digital circuit control system based on a field-programmable gate array (FPGA). It uses digital temperature control, digital detectors, digital down-conversion, digital phase-locked loops, and other digital methods for temperature control, cavity auto-tuning, and crystal phase locking, which improve the integration and flexibility of the circuit system. Meanwhile, a tuning method based on hydrogen flow is proposed, which effectively solves the problem of fluctuations in hydrogen maser resonance frequency with changes in the external environment. Our experimental results show that the designed digital circuit control system meets the requirements of an oven-controlled crystal oscillator (OCXO) loop and a cavity loop. Its frequency stability can reach 2.6×10-13/1 s and 1.4×10-15/10,000 s, which is close to the stability index of ground active hydrogen maser. This scheme has certain practical engineering value, and can be used in the design of hydrogen masers for next-generation space navigation satellites, deep space exploration, and space stations.

Effects of low-dose furosemide combined with aminophylline on the renal function in septic shock patients.

BACKGROUND: To investigate the effects of low-dose furosemide and aminophylline on the renal function in patients with septic shock. METHODS AND RESULTS: A total of 109 eligible septic shock patients in the intensive care unit were randomly divided into a control group (n = 55) and an intervention group (n = 54). The control group received normal saline, and the intervention group received low-dose furosemide (0.048 mg/kg.h-1) with aminophylline (0.3 mg/kg.h-1). The primary outcomes included the levels of serum creatinine (Scr), creatinine clearance rate (Ccr), blood urea nitrogen (BUN), glomerular filtration rate (GFR), and urine output on admission and on days 3, 7 and 14. The secondary outcomes were the sequential organ failure assessment (SOFA) scores, continuous renal replacement therapy (CRRT) time and intensive care unit (ICU) mortality, hospital mortality and 28-day mortality. There were no significant differences in the levels of Scr, Ccr, BUN, or GFR between the two groups, while the urine output was higher in the intervention group on days 3, 7, and 14. Compared with the control group, the SOFA scores, ICU mortality, hospital mortality and 28-day mortality were significantly lower in the intervention group on days 3, 7, and 14, the CRRT time was shorter, and the cumulative fluid balance was lower on days 3 and 7 in the intervention group. CONCLUSIONS: Although low-dose furosemide and aminophylline have fewer protective effects on the renal function in septic shock patients, they could reduce the CRRT time and improve the prognosis.

Value of electrophysiological indicators in differential diagnosis of parkinson's disease and multiple system atrophy.

BACKGROUND: We evaluated the value of electrophysiological indicators by external anal sphincter electromyography (EAS-EMG), sympathetic skin response (SSR), R-R interval variation (RRIV), and Bulbocavernosus Reflex (BCR) in differential diagnosis of multiple system atrophy (MSA) and Parkinson's disease (PD). METHODS: A total of 41 patients with MSA and 32 patients with PD were enrolled. The electrophysiological changes of autonomic dysfunction were assessed with BCR, EAS-EMG, SSR, and RRIV, and the abnormal rate of each indicator was calculated. The diagnostic value of each indicator was analyzed with ROC curve. RESULTS: The incidence rate of autonomic dysfunction in MSA group was significantly higher than that in PD group (p < 0.05). The abnormal rates of BCR and EAS-EMG indicators in MSA group were higher than those in PD group (p < 0.05). The abnormal rates of SSR and RRIV indicators in MSA group and PD group were high; however, there was no significant difference between MSA and PD groups (p > 0.05). The sensitivity of BCR combined with EAS-EMG indicators in differential diagnosis of MSA and PD were 92.3% in males and 86.7% in females, respectively, and the specificity was 72.7% in males and 90% in females, respectively. CONCLUSIONS: Combined analysis of BCR and EAS-EMG has high sensitivity and specificity for differential diagnosis of MSA and PD.

Application of bulbocavernosus reflex combined with anal sphincter electromyography in the diagnosis of MSA and PD.

BACKGROUND: Multiple system atrophy (MSA) and Parkinson's disease (PD) are characterized by abnormal changes in the extrapyramidal system and autonomic nervous system. The two diseases are consistent in some clinical manifestations and few objective indicators for preclinical prediction. METHOD: The value of anal sphincter electromyography (EAS-EMG) in the diagnosis of MSA has been recognized by researchers, while the bulbocavernosus reflex (BCR) has been found to be of great significance in the diagnosis of PD and MSA. In this study, the diagnostic value of BCR combined with EAS-EMG in patients with MSA and PD was further discussed. RESULTS: Forty-three patients with MSA, 120 patients with PD and 40 normal controls were recruited, and the BCR and EAS-EMG were evaluated. The average duration, average amplitude, percentage of polyphasic waves, satellite potential, phase pattern and amplitude of strong contraction were observed. The results showed that the abnormal rate of BCR in the control group was 0%, and the abnormal rate of EAS-EMG was 2.5%; these differences were statistically significant compared with the MSA group (BCR 90.9%, EAS-EMG 93.9%). For patients with PD, there were some significant differences in BCR and EAS-EMG between the control group and the PD group. CONCLUSION: Our study revealed that BCR combined with EAS-EMG detection can provide an objective electrophysiological basis for the diagnosis of MSA and PD, which is beneficial for the early treatment of disease.

Circulating Neutrophil-Derived Microparticles Associated with the Prognosis of Patients with Sepsis.

INTRODUCTION: Because of its high morbidity and mortality, sepsis remains the leading cause of death in the ICU. Microparticles (MP) have been largely studied as potential diagnostic or prognostic markers in various diseases including sepsis. OBJECTIVE: The biological and clinical relevance of neutrophil-derived microparticles (NDMPs) within the MP population remains unclear. The objective of this study was to elucidate the relationship between plasma NDMPs and the prognosis of patients with sepsis and/or septic shock. METHODS: The study was designed as an observational, noninterventional clinical study. The cohort for this study included 40 sepsis and 40 septic shock patients together with 10 healthy controls admitted to the Intensive Care Unit (ICU) and the Health Surveillance Center in the Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong, China, from January to November 2018, respectively. The degree of critical disease for sepsis and septic shock was evaluated, with data analyses conducted from 2018 to 2019. RESULTS: On days 1, 3 and 5 post-admission a series of data including plasma NDMP levels, patient demographics, TNF-α levels, IL-6 levels, sTREM-1 levels, and the sepsis severity score measurements were collected. A survival curve was plotted against levels of plasma NDMPs. Levels of NDMPs were observed to be higher in the septic shock patients than in the sepsis patients on days 1, 3, and 5 post-ICU admission (p < 0.05). NDMP levels were significantly increased in sepsis and septic shock patients with a parallel increase in pro-inflammatory mediators and sepsis severity score (p < 0.05) as well as mortality. CONCLUSION: Our data suggest that NDMPs may be a biomarker of sepsis severity and mortality although its implications on sepsis prognosis warrant further study.

Neutrophil-to-Lymphocyte Ratio and Platelet-to-Lymphocyte Ratio as Potential Predictors of Prognosis in Acute Ischemic Stroke.

Objective: Neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) have been emerging as the novel inflammatory biomarkers for determining the prognosis of various diseases. This study aimed to investigate the individual and joint effects of NLR and PLR on functional outcomes of acute ischemic stroke (AIS). Methods: Our study involved 448 eligible patients with first-ever AIS. Clinical and laboratory data were collected on admission within 72 h from stroke onset. Unfavorable functional outcome was defined as a modified Rankin Scale score of 3-6 at 3 months after AIS. Cox proportional hazard model and spline regression models was used to estimate the effect of NLR and PLR on risk of adverse outcomes after the last patient who completed a 3-months follow-up was enrolled. Results: After adjusting confounders, NLR were significantly associated with the unfavorable functional outcomes (P-trend < 0.001). So were PLR (P-trend < 0.001). NLR was discovered to have higher predictive value than PLR (AUC = 0.776, 95%CI = 0.727-0.825, P < 0.001; AUC = 0.697, 95%CI = 0.641-0.753, P < 0.001). The optimal cutoff values for NLR and PLR was 3.51 and 141.52, respectively. Stratified analysis performed by cox proportional hazard model showed that high level of NLR and PLR (NLR ≥ 3.51, PLR ≥ 141.52) presented the highest risk of unfavorable functional outcomes (adjusted HR, 3.77; 95% CI: 2.38-5.95; P < 0.001). Followed by single high level of NLR (adjusted HR, 2.32; 95% CI: 1.10-4.87; P = 0.027). Single high level of PLR (NLR < 3.51, PLR ≥ 141.52) also showed higher risk than low level of the combination, but it did not reach statistical significance (adjusted HR, 1.42; 95% CI: 0.75-2.70; P = 0.285). No obvious additive [relative excess risk due to interaction (RERI) not significant] or multiplicative (adjusted HR, 0.71; 95%CI: 0.46-1.09; P = 0.114) interaction was found between the effects of NLR and PLR on the risk of unfavorable functional outcomes. Conclusion: This study demonstrated that both NLR and PLR were independent predictors of 3-months functional outcomes of AIS. They may help to identify high-risk patients more forcefully when combined together.

A comparison of contrast transthoracic echocardiography and contrast transcranial Doppler in cryptogenic stroke patients with patent foramen ovale.

OBJECTIVE: In recent years, increasing attention has been paid to cryptogenic stroke (CS) caused by the patent foramen ovale (PFO). This study aims to compare contrast transthoracic echocardiography (cTTE) and contrast transcranial Doppler (cTCD) to determine whether cTTE is more suitable and reliable than cTCD for clinical use. METHODS: From March 2017 to May 2018, patients who suffered from migraines, stroke, hypomnesis, or asymptomatic stroke found casually were included in our study. Patients with CS were semirandomly divided into two groups (cTTE and cTCD) according to the date of the outpatient visit. Patients with either of the examination above found positive were selected to finish transesophageal echocardiography (TEE). RESULTS: In our study, the sensitivities of group cTTE positive (group cTTE+) and group cTCD positive (group cTCD+) did not have any statistical difference (89% vs. 80%, p = 0.236). Focusing on group cTCD+, we discovered that the semiquantitative shunt grading was not correlated with whether a PFO was present or not (p = 0.194). However, once the PFO has been diagnosed, the shunt grading was shown to be related to the width of the gaps (p = 0.032, pdeviation  = 0.03). CONCLUSION: Both cTTE and the cTCD can be used for preliminary PFO findings. The semiquantitative shunt grading of cTCD and cTTE can suggest the size of the PFO and the next course of treatment. The cTTE may be more significant to a safe PFO (a PFO does not have right-to-left shunts, RLSs). Combining cTTE and TEE could help diagnose PFO and assess CS risk.

Platelet-to-neutrophil ratio is a prognostic marker for 90-days outcome in acute ischemic stroke.

To investigate the prognostic value of platelet-to-neutrophil ratio (PNR) in acute ischemic stroke (AIS) patients. In this study, a total of 400 AIS patients were included. Demographic, clinical, laboratory data were collected on admission, and PNR was calculated according to platelet and neutrophil counts on admission. The prognosis after 3 months was evaluated by the Barthel index (BI), where BI ≤85 was defined as poor prognosis and BI >85 was defined as good prognosis. Regression analyses were performed, adjusting for confounders. (1) Compared with good prognosis group, PNR level on admission in poor prognosis group was significantly lower, the difference between the two groups was statistically significant (P < 0.05). (2) The difference in PNR level between the large infarct volume group and small infarct volume group was no statistically significant, nor between the moderate to severe group and the mild group (all P > 0.05). (3) In multivariate logistic regression analysis, PNR, platelet-to-lymphocyte ratio (PLR), platelet-to-white blood cell ratio (PWR) level were correlated with the 3 month prognosis of AIS. PNR may be an independent protective factor for predicting the prognosis of AIS. PNR level has a higher accuracy in the 3 month prognosis of acute ischemic cerebral infarction than the level of PLR and PWR. The level of PNR is correlated with the 3 month prognosis of acute ischemic cerebral infarction. The level of PNR may be an independent protective factor for predicting the prognosis of AIS.

Correlation of Changes in Leukocytes Levels 24 Hours after Intravenous Thrombolysis With Prognosis in Patients With Acute Ischemic Stroke.

OBJECTIVE: Leukocytes play a crucial role in inflammation and immune response. This study aims to demonstrate the value of changes in leukocytes levels 24 hours after intravenous thrombolysis to predict prognosis in acute ischemic stroke (AIS). METHODS: From Jan 2016 to Oct 2017, the patients who suffered AIS to our center within 4.5 hours of symptom onset were all treated with recombinant tissue-type plasminogen activator. Data from 213 AIS patients were analyzed. Patients were divided into 4 groups: persistent leukocytosis (PL), transient leukocytosis (TL), leukocytosis 24 hours (L24H) and no leukocytosis (NL). By comparison, the factors with statistically significant were selected in pairwise multiple comparisons. Good clinical outcome was defined as the Modified Rankin Scale score of 2 or lower. Multivariate logistic regression was used to assess the association of the indicators with clinical outcome. RESULTS: By pairwise multiple comparisons, PL and L24H had higher baseline National Institutes of Health Stroke Scale (NIHSS) score than NL and were likely to lead poor clinical outcomes. TL had a better prognosis than L24H. As the results of multivariable analyses shown, PL and L24H were risk factors to poor functional outcomes (odds ratio [OR] = 2.668, 95% confidence interval [CI] = 1.139-6.249, P = .024; OR = 6.648, 95%CI = 2.048-21.584, P = .002). CONCLUSION: Persistent leukocytosis and leukocytosis 24 hours both had higher baseline NIHSS scores, more serious stroke and were more likely to lead to unfavorable outcome. Therefore, changes in leukocytes levels 24 hours after intravenous thrombolysis could be predicted the short-term functional outcome of AIS patients.