Large atmospheric boundary layer fluctuations and smaller turbine-scale vorticity dynamics are separately hypothesized to initiate the wind turbine wake meandering phenomenon,a coherent,dynamic,turbine-scale oscillati...Large atmospheric boundary layer fluctuations and smaller turbine-scale vorticity dynamics are separately hypothesized to initiate the wind turbine wake meandering phenomenon,a coherent,dynamic,turbine-scale oscillation of the far wake.Triadic interactions,the mechanism of energy transfers between scales,manifest as triples of wavenumbers or frequencies and can be characterized through bispectral analyses.The bispectrum,which correlates the two frequencies to their sum,is calculated by two recently developed multi-dimensional modal decomposition methods:scale-specific energy transfer method and bispectral mode decomposition.Large-eddy simulation of a utility-scale wind turbine in an atmospheric boundary layer with a broad range of large length-scales is used to acquire instantaneous velocity snapshots.The bispectrum from both methods identifies prominent upwind and wake meandering interactions that create a broad range of energy scales including the wake meandering scale.The coherent kinetic energy associated with the interactions shows strong correlation between upwind scales and wake meandering.展开更多
A novel method on designing bispectral windows is proposed in this letter. Compound functions based on a function with binary quadric form, starting from the symmetry characteristic of three-order moments are used as ...A novel method on designing bispectral windows is proposed in this letter. Compound functions based on a function with binary quadric form, starting from the symmetry characteristic of three-order moments are used as the 2-D windowfunctions. Two approaches on how to find the expressions of the compound functions are discussed in detail. One is to approximate the compound function after being Taylor expanded under the Minimum Mean Square Error (MMSE) criteria. Another is to compound the hyperbolic secant function and the binary quadric function directly. According to theoretical analysis, the first type new windows have been proved as slightly better than the conventional ones, the second type new windows are much better than the conventional ones, and the bispectral estimation mean square error approximates to 0.展开更多
Dexmedetomidine has sedative, anxiolytic, analgesic, anti-sympathetic, and anti-shivering effects. Dexmedetomidine might be effective in combination with sevoflurane for anesthesia, but prospective randomized controll...Dexmedetomidine has sedative, anxiolytic, analgesic, anti-sympathetic, and anti-shivering effects. Dexmedetomidine might be effective in combination with sevoflurane for anesthesia, but prospective randomized controlled clinical trials with which to verify this hypothesis are lacking. In total, 120 patients who underwent embolization of an intracranial aneurysm were recruited from Anhui Provincial Hospital and Renmin Hospital of Wuhan University of China and randomly allocated to two groups. After intraoperative administration of 2% to 3% sevoflurane inhalation, one group of patients received pump-controlled intravenous injection of 1.0 ~tg/kg dexmedetomidine for 15 minutes followed by maintenance with 0.3 ~tg/kg/h until the end of surgery; the other group of patients only underwent pump-controlled infusion of saline. Bispectral index monitoring revealed that dexmedetomidine-assisted anesthesia can shorten the recovery time of spon- taneous breathing, time to eye opening, and time to laryngeal mask removal. Before anesthetic induction and immediately after laryngeal mask airway removal, the glucose and lactate levels were low, the S100~ and neuron-specific enolase levels were low, the perioperative blood pressure and heart rate were stable, and postoperative delirium was minimal. These findings indicate that dexmedetomidine can effectively assist sevoflurane for anesthesia during surgical embolization of intracranial aneurysms, shorten the time to consciousness and extubation, reduce the stress response and energy metabolism, stabilize hemodynamic parameters, and reduce adverse reactions, thereby reducing the damage to the central nervous system. This trial was registered at the Chinese Clinical Trial Registry （http：//www.chictr.org. cn/） （registration number： ChiCTR-IPR- 16008113）.展开更多
Objective： To compare the effects of epidural anesthesia with 1.5% lidocaine and 0.5% ropivacaine on propofol requirements, the time to loss of consciousness （LOC）, effect-site propofol concentrations, and the hemo...Objective： To compare the effects of epidural anesthesia with 1.5% lidocaine and 0.5% ropivacaine on propofol requirements, the time to loss of consciousness （LOC）, effect-site propofol concentrations, and the hemodynamic variables during induction of general anesthesia guided by bispectral index （BIS） were studied. Methods： Forty-five patients were divided into three groups to receive epidurally administered saline （Group S）, 1.5% （w/w） lidocaine （Group L）, or 0,5% （w/w） ropivacaine （Group R） Propofol infusion was started to produce blood concentration of 4 lag/ml. Once the BIS value reached 40-50, endotracheal intubation was facilitated by 0.1 mg/kg vecuronium. Measurements included the time to LOC, effect-site propofol concentrations, total propofol dose, mean arterial blood pressure （MABP）, and heart rate （HR） at different study time points. Results： During induction of anesthesia, both Groups L and R were similar for the time to LOC, effect-site propofol concentrations, total propofol dose, MABP, HR, and BIS. The total doses of propofol administered until 1 min post-intubation were significantly less in patients of Groups R and L compared with Group S. MABP and HR were significantly lower following propofol induction compared with baseline values in the three groups, or MABP was significantly increased following intubation as compared with that prior to intubation in Group S but not in Groups R and L while HR was significantly increased following intubation in the three groups. Conclusion： Epidural anesthesia with 1.5% lidocaine and 0.5% ropivacaine has similar effects on the time to LOC, effect-site propofol concentrations, total propofol dose, and the hemodynamic variables during induction of general anesthesia.展开更多
AIM:To determine whether bispectral index (BIS) monitoring is useful for propofol administration for deep sedation during endoscopic retrograde cholangiopancreatography (ERCP). METHODS:Fifty-nine consecutive patients ...AIM:To determine whether bispectral index (BIS) monitoring is useful for propofol administration for deep sedation during endoscopic retrograde cholangiopancreatography (ERCP). METHODS:Fifty-nine consecutive patients with a variety of reasons for ERCP who underwent the procedure at least twice between 1 July 2010 and 30 November 2010. This was a randomized cross-over study, in which each patient underwent ERCP twice, once with BIS monitoring and once with control monitoring. Whether BIS monitoring was done during the first or second ERCP procedure was random. Patients were intermittently administered a mixed regimen including midazolam, pethidine, and propofol by trained nurses. The nurse used a routine practice to monitor sedation using the Modified Observer's Assessment of Alertness/Sedation (MOAA/S) scale or the BIS monitoring. The total amount of midazolam and propofol used and serious side effects were compared between the BIS and control groups. RESULTS:The mean total propofol dose administered was 53.1 ± 32.2 mg in the BIS group and 54.9 ± 30.8 mg in the control group (P = 0.673). The individual propofol dose received per minute during the ERCP procedure was 2.90 ± 1.83 mg/min in the BIS group and 3.44 ± 2.04 mg in the control group (P = 0.103). The median value of the MOAA/S score during the maintenance phase of sedation was comparable for the two groups. The mean BIS values throughout the procedure (from insertion to removal of the endoscope) were 76.5 ± 8.7 for all 59 patients in using the BIS monitor. No significant differences in the frequency of < 80% oxygen saturation, hypotension (< 80 mmHg), or bradycardia (< 50 beats/min) were observed between the two study groups. Four cases of poor cooperation occurred, in which the procedure should be stopped to add the propofol dose. After adding the propofol, the procedure could be conducted successfully (one case in the BIS group, three cases in the control group). The endoscopist rated patient sedation as excellent for all patients in both groups. All patients in both groups rated their level of satisfaction as high (no discomfort). During the post-procedural follow-up in the recovery area, no cases of clinically significant hypoxic episodes were recorded in either group. No other postoperative side effects related to sedation were observed in either group. CONCLUSION:BIS monitoring trend to slighlty reduce the mean propofol dose. Nurse-administered propofol sedation under the supervision of a gastroenterologist may be considered an alternative under anesthesiologist.展开更多
BACKGROUND: The bispectral(BIS) index is a processed electroencephalogram(EEG) parameter with extensive validation and demonstrated clinical utility. The study aimed to investigate the correlation between the BIS inde...BACKGROUND: The bispectral(BIS) index is a processed electroencephalogram(EEG) parameter with extensive validation and demonstrated clinical utility. The study aimed to investigate the correlation between the BIS index and the prognosis of patients with coma in the ICU.METHODS: A total of 208 patients with coma in the ICU were enrolled in this study. According to the BIS value, the patients were divided into four groups: group I, BIS value 0 to 20; group II, BIS value 21 to 40; group III, BIS value 41 to 60; and group IV, BIS value greater than 60. The difference in BIS values with the differences in prognosis of patients with coma was compared between the four groups, and the prognosis of patients with coma was stratified into consciousness, coma, vegetative state, and brain death. Subsequently, the best cut-off score of BIS values calculated for determining the correlation between BIS value and mental state was proposed.RESULTS: There are no significant differences in the age and APACHE II scores between the four groups(P>0.05). An inverse correlation was observed between BIS value and mental state(r= –0.749, P=0.00). According to the ROC curve, as BIS value was greater than 42.5, there were higher sensitivity and specificity in conscious-coma patients.CONCLUSION: BIS value is correlated with the prognosis of patients with coma in ICU, and BIS value can be a useful marker for estimating the prognosis of comatose patients.展开更多
Objective:To discuss the efficacy of Bispectral index (BIS)-monitored closed-loop targeted-controlled infusion of propofol for laparoscopic radical operation for gastric cancer.Methods:A total of 106 patients with pri...Objective:To discuss the efficacy of Bispectral index (BIS)-monitored closed-loop targeted-controlled infusion of propofol for laparoscopic radical operation for gastric cancer.Methods:A total of 106 patients with primary gastric cancer who underwent laparoscopic radical operation for gastric cancer in our hospital between August 2015 and February 2018 were chosen as the research subjects and divided into the control group (n=53) and the observation group (n=53) according to the different anesthesia methods. Control group of patients received BIS-monitored manually adjusted targeted-controlled infusion concentration of propofol, and observation group of patients received BIS-monitored closed-loop targeted-controlled infusion of propofol. The differences in hemodynamic index levels as well as serum contents of inflammatory factors and stress hormones were compared between the two groups of patients before anesthesia (T0), 30 min after surgery started (T1) and 30 min before surgery ended (T2).Results:At T0, the differences in hemodynamic index levels as well as serum contents of inflammatory factors and stress hormones were not statistically significant between the two groups. At T1 and T2, hemodynamic indexes MAP and HR levels of observation group were lower than those of control group at the corresponding time points;serum inflammatory factors sICAM-1, IL-1β, IL-8 and TNF-α contents were lower than those of control group at the corresponding time points;serum stress hormones Cor, T4 and glucagon contents were lower than those of control group at the corresponding time points.Conclusion: BIS-monitored closed-loop targeted-controlled infusion of propofol can effectively stabilize the intraoperative hemodynamics and inhibit the systemic inflammatory stress response in patients with laparoscopic radical operation for gastric cancer.展开更多
Objective： Transcatheter aortic valve implantation （TAVI） is a minimally invasive therapy for elderly patients with severe aortic valve stenosis who were refused surgical aortic valve replacement because of the hig...Objective： Transcatheter aortic valve implantation （TAVI） is a minimally invasive therapy for elderly patients with severe aortic valve stenosis who were refused surgical aortic valve replacement because of the high perioperative risk. Traditionally, this procedure has been done under general anesthesia, but more recently local anesthesia and sedation have become popular. This research assessed the effectiveness of transfemoral TAVI under bispectral index （BIS）-guided sedation. Methods： In this single-center retrospective control analysis, clinical data, including demographic characteristics, echocardiography, periprocedural data, and main complications, were collected and assessed in 113 patients undergoing TAVI through the femoral artery under general anesthesia （GA group, n=36） and under BIS-guided sedation （SED group, n=77）. Results： The demographic characteristics and echocardi-ographic parameters between the two groups were similar （P〉0.05）. Two （2.6%） of patients were moved from BIS-guided sedation to general anesthesia for surgical reasons. Procedures were significantly shorter in the SED group than in the GA group （（127.10±44.43） min vs. （165.90±71.62） min, P=0.004）. Patients in the SED group lost less blood and received significantly fewer red blood cells and catecholamines than those in the GA group （5.19% vs. 22.22%, P=0.017 and 67.53% vs. 97.22%, P〈0.001）. The length of hospital stay was significantly shorter and there were fewer pulmonary complications in the SED group than in the GA group. Thirty-day mortality was similar between the two groups. Conclusions： BIS-guided sedation is a feasible and safe approach for transfemoral TAVl. The anes- thesiologist should choose the best anesthetic method according to the team＇s experience.展开更多
Estimation of model parameter for transient signal is very important in many aspects. This paper presents a new Markov ARMA model Q-slice estimation algorithm for transient signal based on bispectrum. Simulation resul...Estimation of model parameter for transient signal is very important in many aspects. This paper presents a new Markov ARMA model Q-slice estimation algorithm for transient signal based on bispectrum. Simulation results show that this new method has some special features, such as higher estimation precision, lower amount of calculation, higher fitting effect even in lower signal-to-noise ratio (SNR) situation.展开更多
Complex proteins are needed for many biological activities.Folding amino acid chains reveals their properties and functions.They support healthy tissue structure,physiology,and homeostasis.Precision medicine and treat...Complex proteins are needed for many biological activities.Folding amino acid chains reveals their properties and functions.They support healthy tissue structure,physiology,and homeostasis.Precision medicine and treatments require quantitative protein identification and function.Despite technical advances and protein sequence data exploration,bioinformatics’“basic structure”problem—the automatic deduction of a protein’s properties from its amino acid sequence—remains unsolved.Protein function inference from amino acid sequences is the main biological data challenge.This study analyzes whether raw sequencing can characterize biological facts.A massive corpus of protein sequences and the Globin-like superfamily’s related protein families generate a solid vector representation.A coding technique for each sequence in each family was devised using two representations to identify each amino acid precisely.A bispectral analysis converts encoded protein numerical sequences into images for better protein sequence and family discrimination.Training and validation employed 70%of the dataset,while 30%was used for testing.This paper examined the performance of multistage deep learning models for differentiating between sixteen protein families after encoding and representing each encoded sequence by a higher spectral representation image(Bispectrum).Cascading minimized false positive and negative cases in all phases.The initial stage focused on two classes(six groups and ten groups).The subsequent stages focused on the few classes almost accurately separated in the first stage and decreased the overlapping cases between families that appeared in single-stage deep learning classification.The single-stage technique had 64.2%+/-22.8%accuracy,63.3%+/-17.1%precision,and a 63.2%+/19.4%F1-score.The two-stage technique yielded 92.2%+/-4.9%accuracy,92.7%+/-7.0%precision,and a 92.3%+/-5.0%F1-score.This work provides balanced,reliable,and precise forecasts for all families in all measures.It ensured that the new model was resilient to family variances and provided high-scoring results.展开更多
Proteins are essential for many biological functions.For example,folding amino acid chains reveals their functionalities by maintaining tissue structure,physiology,and homeostasis.Note that quantifiable protein charac...Proteins are essential for many biological functions.For example,folding amino acid chains reveals their functionalities by maintaining tissue structure,physiology,and homeostasis.Note that quantifiable protein characteristics are vital for improving therapies and precision medicine.The automatic inference of a protein’s properties from its amino acid sequence is called“basic structure”.Nevertheless,it remains a critical unsolved challenge in bioinformatics,although with recent technological advances and the investigation of protein sequence data.Inferring protein function from amino acid sequences is crucial in biology.This study considers using raw sequencing to explain biological facts using a large corpus of protein sequences and the Globin-like superfamily to generate a vector representation.The power of two representations was used to identify each amino acid,and a coding technique was established for each sequence family.Subsequently,the encoded protein numerical sequences are transformed into an image using bispectral analysis to identify essential characteristics for discriminating between protein sequences and their families.A deep Convolutional Neural Network(CNN)classifies the resulting images and developed non-normalized and normalized encoding techniques.Initially,the dataset was split 70/30 for training and testing.Correspondingly,the dataset was utilized for 70%training,15%validation,and 15%testing.The suggested methods are evaluated using accuracy,precision,and recall.The non-normalized method had 70%accuracy,72%precision,and 71%recall.68%accuracy,67%precision,and 67%recall after validation.Meanwhile,the normalized approach without validation had 92.4%accuracy,94.3%precision,and 91.1%recall.Validation showed 90%accuracy,91.2%precision,and 89.7%recall.Note that both algorithms outperform the rest.The paper presents that bispectrum-based nonlinear analysis using deep learning models outperforms standard machine learning methods and other deep learning methods based on convolutional architecture.They offered the best inference performance as the proposed approach improves categorization and prediction.Several instances show successful multi-class prediction in molecular biology’s massive data.展开更多
Liver transplantation (LT) recipients are known to require less anesthetic agents. Providing minimally required anesthetics while avoiding awareness is especially important in LT recipients because it would help manag...Liver transplantation (LT) recipients are known to require less anesthetic agents. Providing minimally required anesthetics while avoiding awareness is especially important in LT recipients because it would help manage perioperative hemodynamic instability with less vasopressor and fast track recovery. This study aims to compare state entropy (SE) against bispectral index (BIS) during isoflurane anesthesia in LT. We adjusted anesthesia to BIS values 40 - 60, and compared it with concomitant SE values. BIS, SE values, and anesthetic requirements according to liver failure severity, etiology and LT stages were analyzed. For BIS-SE differences, SE value that is different from the concomitant BIS by more than 15 was defined as a significant disagreement. Mann Whitney, Kruskal Wallis test and a Poisson exact test were used for analysis. The BIS-SE pair sets of 2895 from 38 patients were analyzed. BIS, SE values and anesthetic requirements were significantly lower in MELD ≥ 20 (p < 0.001 in all) and in alcoholic etiology (p < 0.001 in all). For BIS-SE differences, 320 disagreement data pairs were seen at a rate of 1.33 times/hr (95% CI = [1.19, 1.48], p < 0.001). A significant disagreement was delineated in MELD score ≥ 20 (3.04 times/hr, CI = [2.64, 3.49], p < 0.001), alcoholic etiology (3.19 times/hr, [2.67, 3.78], p < 0.001) and postreperfusion stage (1.63 times/hr, [1.43, 1.85], p < 0.001). In these significant BIS-SE differences, 95.9% (307/320 disagreement data pairs) showed higher BIS than SE. In conclusion, in high MELD and alcoholic etiology, anesthetic requirements were significantly less, and BIS and SE showed great discrepancy with lower SE values. Therefore, when SE monitoring is used during LT, anesthesiologists may need to consider that in high MELD and alcoholic etiology, SE tends to show lower values than the concomitant BIS values that are within optimal anesthetic depth ranges.展开更多
<b><span style="font-family:Verdana;">Background:</span></b><span style="font-family:Verdana;"> The bispectral index (BIS) derived from the electroencephalogram is an ...<b><span style="font-family:Verdana;">Background:</span></b><span style="font-family:Verdana;"> The bispectral index (BIS) derived from the electroencephalogram is an additional means of monitoring the depth of narcosis.</span><span style="font-family:Verdana;"> </span><b><span style="font-family:Verdana;">Objective:</span></b><span style="font-family:Verdana;"> To compare the monitoring of the depth of narcosis by the BIS associated with clinical data versus standard monitoring at the University Hospital of Parakou in Benin in 2019.</span><span style="font-family:Verdana;"> </span><b><span style="font-family:Verdana;">Methods:</span></b><span style="font-family:Verdana;"> This was an observational study for descriptive and analytical purposes with prospective data collection, carried out in general surgery and intensive care unit for 4 months. The inclusion criteria were: an age ≥ 18 years, an ASA score ≤ 3, surgery under general anesthesia and informed consent of the patient. Two groups were formed: non-BIS group monitored by clinical parameters (PA, FC, FR, EtCO</span><sub><span style="font-family:Verdana;vertical-align:sub;">2</span></sub><span style="font-family:Verdana;">, and SpO</span><sub><span style="font-family:Verdana;vertical-align:sub;">2</span></sub><span style="font-family:Verdana;">) only and BIS group monitored by bispectral index in addition to clinical parameters. Patients were seen 48 hours after the procedure.</span><span style="font-family:Verdana;"> </span><b><span style="font-family:Verdana;">Results:</span></b><b><span style="font-family:Verdana;"> </span></b><span style="font-family:Verdana;">36 patients were collected. The mean age was 40.63 ± 16.77 years with a sex ratio of 3. ASA 1 patients represented 86.11% of the sample and ASA2 patients 13.89%. The average doses of Propofol were not significantly reduced in the BIS group (p = 0.555). On the other hand, the period of intraoperative recovery (p-value = 0.007) and the NVPO (p = 0.043;OR = 0.10;95% CI [0.01 - 0.97]) were significantly reduced by the use of BIS. One case of intraoperative memorization (2.78%) was however found in the BIS group.</span><span style="font-family:Verdana;"> </span><b><span style="font-family:Verdana;">Conclusion:</span></b><span style="font-family:Verdana;"> The bispectral index makes it possible to significantly reduce the risk of intraoperative awakening and PONV, and not significantly reduce the consumption of Propofol.</span>展开更多
In order to evaluate the accuracy of bispectral estimation method, signals of cosine function were adopted. Because the cosine signals’ three order moment spectrum and three order cumulant spectrum are zero, Non zero...In order to evaluate the accuracy of bispectral estimation method, signals of cosine function were adopted. Because the cosine signals’ three order moment spectrum and three order cumulant spectrum are zero, Non zero part of the bispectrum estimated by no matter which method is the estimation error. Through the comparison of three kinds of estimation methods: the direct method, indirect method and AR parameter method, errors of various estimation methods were obtained, then changing the values of different parameters in all methods, and observing the bispectral error values changes with the parameters, so as to provide a basis for the various bispectrum estimation method and the selection.展开更多
With the rapid development of detection technology and artificial intelligence,the widespread use of multispectral detectors has increased challenges to stealth capabilities.This paper presents a bispectral camouflage...With the rapid development of detection technology and artificial intelligence,the widespread use of multispectral detectors has increased challenges to stealth capabilities.This paper presents a bispectral camouflage metasurface with microwave diffuse emission and tunable infrared(IR)emissivity,achieving an integrated design for radar cross-section(RCS)reduction and tunable IR emissivity.The structure consists of layers from bottom to top:aerogel felt,indium-tin-oxide(ITO),air,polyethylene terephthalate(PET),and ITO.It reduces RCS through microwave diffuse reflection and adjusts IR emissivity by controlling the ITO fill ratio.Both simulations and experiments demonstrate effective suppression of electromagnetic(EM)wave backscattering within4.5-10.3 GHz,achieving radar invisibility.The tunable IR emissivity ranges from 0.2 to 0.7 with good thermal insulation.This design alleviates issues related to structural thickness and processing complexity and avoids increased thermal load from microwave absorption,offering better tunable IR emissivity for various thermal camouflage environments.This metasurface holds significant promise for multispectral stealth and IR camouflage applications.展开更多
Imaging through scattering media remains a formidable challenge in optical imaging.Exploiting the memory effect presents new opportunities for non-invasive imaging through the scattering medium by leveraging speckle c...Imaging through scattering media remains a formidable challenge in optical imaging.Exploiting the memory effect presents new opportunities for non-invasive imaging through the scattering medium by leveraging speckle correlations.Traditional speckle correlation imaging often utilizes a random phase as the initial phase,leading to challenges such as convergence to incorrect local minima and the inability to resolve ambiguities in object orientation.Here,a novel method for high-quality reconstruction of single-shot scattering imaging is proposed.By employing the initial phase obtained from bispectral analysis in the subsequent phase retrieval algorithm,the convergence and accuracy of the reconstruction process are notably improved.Furthermore,a robust search technique based on an image clarity evaluation function successfully determines the optimal reconstruction size.The study demonstrates that the proposed method can obtain high-quality reconstructed images compared with the existing scattering imaging approaches.This innovative approach to non-invasive single-shot imaging through strongly scattering media shows potential for applications in scenarios involving moving objects or dynamic scattering imaging scenes.展开更多
Importance:The closed-loop infusion system can automatically adjust and maintain the depth of anesthesia by using the propofol target-controlled infusion(TCI)model under the feedback guidance of the bispectral index(B...Importance:The closed-loop infusion system can automatically adjust and maintain the depth of anesthesia by using the propofol target-controlled infusion(TCI)model under the feedback guidance of the bispectral index(BIS).Objective:To evaluate the safety and superiority of closed-loop TCI of propofol guided by BIS during maintenance of generalized intravenous anesthesia for preschool children.Methods:A total of 120 children aged 1–6 years were enrolled and were divided into a closed-loop feedback group(Group C)and an open-loop manual control group(Group O),with 60 participants in each group.For anesthesia maintenance,the propofol infusion rate was adjusted by the injection system under the guidance of BIS in Group C and was manually adjusted by anesthesiologists according to the BIS and clinical experience in Group O,to maintain a BIS level of 50.The time ratio of adequate anesthesia(40≤BIS≤60),light anesthesia(BIS>60),and deep anesthesia(BIS<40)were recorded.Results:A total of 119 patients(59 in Group C and 60 in Group O)were enrolled in the study.Group C demonstrated a higher time ratio of adequate anesthesia(P=0.014)compared to Group O.The time ratio of light anesthesia and the global score was lower in Group C than in Group O(P=0.010,P=0.015,respectively).The frequency of adjustment per unit of time was higher in Group C for propofol(P<0.001),while it was lower for remifentanil(P=0.010).Interpretation:BIS-guided closed-loop infusion of propofol is safe and effective for preschool children.The depth of anesthesia is controlled more accurately and smoothly.展开更多
Background Awareness is a serious complication of general anesthesia. In China, the incidence of intraoperative awareness was 1% in patients undergoing total intravenous anesthesia （TIVA）. In this study, we compared...Background Awareness is a serious complication of general anesthesia. In China, the incidence of intraoperative awareness was 1% in patients undergoing total intravenous anesthesia （TIVA）. In this study, we compared the incidence of awareness between Bispectral index （BIS）-guided and routine TIVA protocol and evaluated the effect of BIS on preventing awareness. Methods A prospective, randomized, double-blinded, multicenter controlled trial was performed. Patients （〉18 years of age） undergoing TIVA were randomly divided into BIS-guided group （Group A, BIS was monitored and recommended to maintain between 40-60） and control group （Group B, BIS was monitored but the screen was covered）. The intraoperative BIS values were downloaded and the BIS trends of confirmed awareness cases were analyzed to determine whether light anesthesia existed. Results Of the total 5228 patients, 2919 patients were assigned to Group A and 2309 to Group B. Four cases of confirmed awareness （0.14%） were reported in the BIS-guided group and 15 （0.65%） in the control group （P=-0.002, OR=0.21, 95% confidence intervals： 0.07-0.63）. The incidence of possible awareness （0.14% vs. 0.26%, P=0.485） and dreaming （3.1% vs. 3.1%, P=0.986） was comparable between BIS-guided group and the control group. Among the 19 confirmed awareness cases, intraoperative BIS trends of six cases were downloaded and identified. Five of them showed signs of light anesthesia as BIS 〉60 and lasted 19-106 minutes, whereas one case had a stable BIS trend and the values were within 60 during the operation. Another five awareness cases were reviewed for anesthesia procedures, of which improper light anesthesia were confirmed. Conclusions BIS-guided TIVA （BIS was recommended to maintain between 40-60） decreased the risk of awareness compared with routine TIVA. The main reason for awareness was light anesthesia.展开更多
Background Wavelet index （WLI） is a new parameter for monitoring depth of anesthesia based on Wavelet analysis. We observed the change of WLI and bispectral index （BIS） in patients regain of consciousness （ROC） ...Background Wavelet index （WLI） is a new parameter for monitoring depth of anesthesia based on Wavelet analysis. We observed the change of WLI and bispectral index （BIS） in patients regain of consciousness （ROC） in the absence of frontalis electromyographic （EMG） interference. The aim of this study was to compare the ability of WLI and BIS for reflecting ROC in patients undergone surgery. Methods Twelve patients who were scheduled for maxillofacial surgeries were enrolled in the study. BIS and WLI values were monitored continually. After being given midazolam and remifentanil, patients were asked to squeeze the investigator＇s hand ever 30 seconds. Patients were continuously given propofol until loss of consciousness （LOC1）. Tunstalrs isolated forearm technique was used to test the surgical consciousness in patients. After total muscle relaxation endotracheal intubations were performed, and the patients were connected to a ventilator. Then, propofol was withdrawn until the patients showed regain of consciousness （ROC1） and an awareness reaction. After the command test, patients were readministered with propofol until loss of consciousness （LOC2）. After surgery, all of the sedatives were withdrawn, and the patients were let to regain consciousness （ROC2）, Results The BIS values of twelve patients at ROC1 after using muscle relaxant were much lower than those at LOC1 and ROC2 without using muscle relaxant, showing statistical significance （P 〈0.05）. Meanwhile, the WLI values of twelve patients at ROC1 after using muscle relaxant were much higher than those at LOC1 and equal to ROC2 without using muscle relaxant, showing statistical significances （P 〈0.05） between ROC1 and LOCI. Conclusions This study showed that under muscle relaxation or facial paralysis, when there is no EMG signal, BIS can not accurately reflect regain of consciousness in surgical patients, but WLI can reflect it accurately. So WLI may have advantages for reflecting state of consciousness in surgical patients.展开更多
基金supported by the National Science Foundation(Grant No.21-36371)supported by the National Science Foundation(Grant Nos.21-38259,21-38286,21-38307,21-37603,and 21-38296)。
文摘Large atmospheric boundary layer fluctuations and smaller turbine-scale vorticity dynamics are separately hypothesized to initiate the wind turbine wake meandering phenomenon,a coherent,dynamic,turbine-scale oscillation of the far wake.Triadic interactions,the mechanism of energy transfers between scales,manifest as triples of wavenumbers or frequencies and can be characterized through bispectral analyses.The bispectrum,which correlates the two frequencies to their sum,is calculated by two recently developed multi-dimensional modal decomposition methods:scale-specific energy transfer method and bispectral mode decomposition.Large-eddy simulation of a utility-scale wind turbine in an atmospheric boundary layer with a broad range of large length-scales is used to acquire instantaneous velocity snapshots.The bispectrum from both methods identifies prominent upwind and wake meandering interactions that create a broad range of energy scales including the wake meandering scale.The coherent kinetic energy associated with the interactions shows strong correlation between upwind scales and wake meandering.
文摘A novel method on designing bispectral windows is proposed in this letter. Compound functions based on a function with binary quadric form, starting from the symmetry characteristic of three-order moments are used as the 2-D windowfunctions. Two approaches on how to find the expressions of the compound functions are discussed in detail. One is to approximate the compound function after being Taylor expanded under the Minimum Mean Square Error (MMSE) criteria. Another is to compound the hyperbolic secant function and the binary quadric function directly. According to theoretical analysis, the first type new windows have been proved as slightly better than the conventional ones, the second type new windows are much better than the conventional ones, and the bispectral estimation mean square error approximates to 0.
基金supported by the National Natural Science Foundation of China,No.81671891
文摘Dexmedetomidine has sedative, anxiolytic, analgesic, anti-sympathetic, and anti-shivering effects. Dexmedetomidine might be effective in combination with sevoflurane for anesthesia, but prospective randomized controlled clinical trials with which to verify this hypothesis are lacking. In total, 120 patients who underwent embolization of an intracranial aneurysm were recruited from Anhui Provincial Hospital and Renmin Hospital of Wuhan University of China and randomly allocated to two groups. After intraoperative administration of 2% to 3% sevoflurane inhalation, one group of patients received pump-controlled intravenous injection of 1.0 ~tg/kg dexmedetomidine for 15 minutes followed by maintenance with 0.3 ~tg/kg/h until the end of surgery; the other group of patients only underwent pump-controlled infusion of saline. Bispectral index monitoring revealed that dexmedetomidine-assisted anesthesia can shorten the recovery time of spon- taneous breathing, time to eye opening, and time to laryngeal mask removal. Before anesthetic induction and immediately after laryngeal mask airway removal, the glucose and lactate levels were low, the S100~ and neuron-specific enolase levels were low, the perioperative blood pressure and heart rate were stable, and postoperative delirium was minimal. These findings indicate that dexmedetomidine can effectively assist sevoflurane for anesthesia during surgical embolization of intracranial aneurysms, shorten the time to consciousness and extubation, reduce the stress response and energy metabolism, stabilize hemodynamic parameters, and reduce adverse reactions, thereby reducing the damage to the central nervous system. This trial was registered at the Chinese Clinical Trial Registry （http：//www.chictr.org. cn/） （registration number： ChiCTR-IPR- 16008113）.
基金Project (No. 419200-584602) supported by the Start Foundation for Introducing Talent of Zhejiang University, China
文摘Objective： To compare the effects of epidural anesthesia with 1.5% lidocaine and 0.5% ropivacaine on propofol requirements, the time to loss of consciousness （LOC）, effect-site propofol concentrations, and the hemodynamic variables during induction of general anesthesia guided by bispectral index （BIS） were studied. Methods： Forty-five patients were divided into three groups to receive epidurally administered saline （Group S）, 1.5% （w/w） lidocaine （Group L）, or 0,5% （w/w） ropivacaine （Group R） Propofol infusion was started to produce blood concentration of 4 lag/ml. Once the BIS value reached 40-50, endotracheal intubation was facilitated by 0.1 mg/kg vecuronium. Measurements included the time to LOC, effect-site propofol concentrations, total propofol dose, mean arterial blood pressure （MABP）, and heart rate （HR） at different study time points. Results： During induction of anesthesia, both Groups L and R were similar for the time to LOC, effect-site propofol concentrations, total propofol dose, MABP, HR, and BIS. The total doses of propofol administered until 1 min post-intubation were significantly less in patients of Groups R and L compared with Group S. MABP and HR were significantly lower following propofol induction compared with baseline values in the three groups, or MABP was significantly increased following intubation as compared with that prior to intubation in Group S but not in Groups R and L while HR was significantly increased following intubation in the three groups. Conclusion： Epidural anesthesia with 1.5% lidocaine and 0.5% ropivacaine has similar effects on the time to LOC, effect-site propofol concentrations, total propofol dose, and the hemodynamic variables during induction of general anesthesia.
文摘AIM:To determine whether bispectral index (BIS) monitoring is useful for propofol administration for deep sedation during endoscopic retrograde cholangiopancreatography (ERCP). METHODS:Fifty-nine consecutive patients with a variety of reasons for ERCP who underwent the procedure at least twice between 1 July 2010 and 30 November 2010. This was a randomized cross-over study, in which each patient underwent ERCP twice, once with BIS monitoring and once with control monitoring. Whether BIS monitoring was done during the first or second ERCP procedure was random. Patients were intermittently administered a mixed regimen including midazolam, pethidine, and propofol by trained nurses. The nurse used a routine practice to monitor sedation using the Modified Observer's Assessment of Alertness/Sedation (MOAA/S) scale or the BIS monitoring. The total amount of midazolam and propofol used and serious side effects were compared between the BIS and control groups. RESULTS:The mean total propofol dose administered was 53.1 ± 32.2 mg in the BIS group and 54.9 ± 30.8 mg in the control group (P = 0.673). The individual propofol dose received per minute during the ERCP procedure was 2.90 ± 1.83 mg/min in the BIS group and 3.44 ± 2.04 mg in the control group (P = 0.103). The median value of the MOAA/S score during the maintenance phase of sedation was comparable for the two groups. The mean BIS values throughout the procedure (from insertion to removal of the endoscope) were 76.5 ± 8.7 for all 59 patients in using the BIS monitor. No significant differences in the frequency of < 80% oxygen saturation, hypotension (< 80 mmHg), or bradycardia (< 50 beats/min) were observed between the two study groups. Four cases of poor cooperation occurred, in which the procedure should be stopped to add the propofol dose. After adding the propofol, the procedure could be conducted successfully (one case in the BIS group, three cases in the control group). The endoscopist rated patient sedation as excellent for all patients in both groups. All patients in both groups rated their level of satisfaction as high (no discomfort). During the post-procedural follow-up in the recovery area, no cases of clinically significant hypoxic episodes were recorded in either group. No other postoperative side effects related to sedation were observed in either group. CONCLUSION:BIS monitoring trend to slighlty reduce the mean propofol dose. Nurse-administered propofol sedation under the supervision of a gastroenterologist may be considered an alternative under anesthesiologist.
文摘BACKGROUND: The bispectral(BIS) index is a processed electroencephalogram(EEG) parameter with extensive validation and demonstrated clinical utility. The study aimed to investigate the correlation between the BIS index and the prognosis of patients with coma in the ICU.METHODS: A total of 208 patients with coma in the ICU were enrolled in this study. According to the BIS value, the patients were divided into four groups: group I, BIS value 0 to 20; group II, BIS value 21 to 40; group III, BIS value 41 to 60; and group IV, BIS value greater than 60. The difference in BIS values with the differences in prognosis of patients with coma was compared between the four groups, and the prognosis of patients with coma was stratified into consciousness, coma, vegetative state, and brain death. Subsequently, the best cut-off score of BIS values calculated for determining the correlation between BIS value and mental state was proposed.RESULTS: There are no significant differences in the age and APACHE II scores between the four groups(P>0.05). An inverse correlation was observed between BIS value and mental state(r= –0.749, P=0.00). According to the ROC curve, as BIS value was greater than 42.5, there were higher sensitivity and specificity in conscious-coma patients.CONCLUSION: BIS value is correlated with the prognosis of patients with coma in ICU, and BIS value can be a useful marker for estimating the prognosis of comatose patients.
文摘Objective:To discuss the efficacy of Bispectral index (BIS)-monitored closed-loop targeted-controlled infusion of propofol for laparoscopic radical operation for gastric cancer.Methods:A total of 106 patients with primary gastric cancer who underwent laparoscopic radical operation for gastric cancer in our hospital between August 2015 and February 2018 were chosen as the research subjects and divided into the control group (n=53) and the observation group (n=53) according to the different anesthesia methods. Control group of patients received BIS-monitored manually adjusted targeted-controlled infusion concentration of propofol, and observation group of patients received BIS-monitored closed-loop targeted-controlled infusion of propofol. The differences in hemodynamic index levels as well as serum contents of inflammatory factors and stress hormones were compared between the two groups of patients before anesthesia (T0), 30 min after surgery started (T1) and 30 min before surgery ended (T2).Results:At T0, the differences in hemodynamic index levels as well as serum contents of inflammatory factors and stress hormones were not statistically significant between the two groups. At T1 and T2, hemodynamic indexes MAP and HR levels of observation group were lower than those of control group at the corresponding time points;serum inflammatory factors sICAM-1, IL-1β, IL-8 and TNF-α contents were lower than those of control group at the corresponding time points;serum stress hormones Cor, T4 and glucagon contents were lower than those of control group at the corresponding time points.Conclusion: BIS-monitored closed-loop targeted-controlled infusion of propofol can effectively stabilize the intraoperative hemodynamics and inhibit the systemic inflammatory stress response in patients with laparoscopic radical operation for gastric cancer.
文摘Objective： Transcatheter aortic valve implantation （TAVI） is a minimally invasive therapy for elderly patients with severe aortic valve stenosis who were refused surgical aortic valve replacement because of the high perioperative risk. Traditionally, this procedure has been done under general anesthesia, but more recently local anesthesia and sedation have become popular. This research assessed the effectiveness of transfemoral TAVI under bispectral index （BIS）-guided sedation. Methods： In this single-center retrospective control analysis, clinical data, including demographic characteristics, echocardiography, periprocedural data, and main complications, were collected and assessed in 113 patients undergoing TAVI through the femoral artery under general anesthesia （GA group, n=36） and under BIS-guided sedation （SED group, n=77）. Results： The demographic characteristics and echocardi-ographic parameters between the two groups were similar （P〉0.05）. Two （2.6%） of patients were moved from BIS-guided sedation to general anesthesia for surgical reasons. Procedures were significantly shorter in the SED group than in the GA group （（127.10±44.43） min vs. （165.90±71.62） min, P=0.004）. Patients in the SED group lost less blood and received significantly fewer red blood cells and catecholamines than those in the GA group （5.19% vs. 22.22%, P=0.017 and 67.53% vs. 97.22%, P〈0.001）. The length of hospital stay was significantly shorter and there were fewer pulmonary complications in the SED group than in the GA group. Thirty-day mortality was similar between the two groups. Conclusions： BIS-guided sedation is a feasible and safe approach for transfemoral TAVl. The anes- thesiologist should choose the best anesthetic method according to the team＇s experience.
文摘Estimation of model parameter for transient signal is very important in many aspects. This paper presents a new Markov ARMA model Q-slice estimation algorithm for transient signal based on bispectrum. Simulation results show that this new method has some special features, such as higher estimation precision, lower amount of calculation, higher fitting effect even in lower signal-to-noise ratio (SNR) situation.
文摘Complex proteins are needed for many biological activities.Folding amino acid chains reveals their properties and functions.They support healthy tissue structure,physiology,and homeostasis.Precision medicine and treatments require quantitative protein identification and function.Despite technical advances and protein sequence data exploration,bioinformatics’“basic structure”problem—the automatic deduction of a protein’s properties from its amino acid sequence—remains unsolved.Protein function inference from amino acid sequences is the main biological data challenge.This study analyzes whether raw sequencing can characterize biological facts.A massive corpus of protein sequences and the Globin-like superfamily’s related protein families generate a solid vector representation.A coding technique for each sequence in each family was devised using two representations to identify each amino acid precisely.A bispectral analysis converts encoded protein numerical sequences into images for better protein sequence and family discrimination.Training and validation employed 70%of the dataset,while 30%was used for testing.This paper examined the performance of multistage deep learning models for differentiating between sixteen protein families after encoding and representing each encoded sequence by a higher spectral representation image(Bispectrum).Cascading minimized false positive and negative cases in all phases.The initial stage focused on two classes(six groups and ten groups).The subsequent stages focused on the few classes almost accurately separated in the first stage and decreased the overlapping cases between families that appeared in single-stage deep learning classification.The single-stage technique had 64.2%+/-22.8%accuracy,63.3%+/-17.1%precision,and a 63.2%+/19.4%F1-score.The two-stage technique yielded 92.2%+/-4.9%accuracy,92.7%+/-7.0%precision,and a 92.3%+/-5.0%F1-score.This work provides balanced,reliable,and precise forecasts for all families in all measures.It ensured that the new model was resilient to family variances and provided high-scoring results.
文摘Proteins are essential for many biological functions.For example,folding amino acid chains reveals their functionalities by maintaining tissue structure,physiology,and homeostasis.Note that quantifiable protein characteristics are vital for improving therapies and precision medicine.The automatic inference of a protein’s properties from its amino acid sequence is called“basic structure”.Nevertheless,it remains a critical unsolved challenge in bioinformatics,although with recent technological advances and the investigation of protein sequence data.Inferring protein function from amino acid sequences is crucial in biology.This study considers using raw sequencing to explain biological facts using a large corpus of protein sequences and the Globin-like superfamily to generate a vector representation.The power of two representations was used to identify each amino acid,and a coding technique was established for each sequence family.Subsequently,the encoded protein numerical sequences are transformed into an image using bispectral analysis to identify essential characteristics for discriminating between protein sequences and their families.A deep Convolutional Neural Network(CNN)classifies the resulting images and developed non-normalized and normalized encoding techniques.Initially,the dataset was split 70/30 for training and testing.Correspondingly,the dataset was utilized for 70%training,15%validation,and 15%testing.The suggested methods are evaluated using accuracy,precision,and recall.The non-normalized method had 70%accuracy,72%precision,and 71%recall.68%accuracy,67%precision,and 67%recall after validation.Meanwhile,the normalized approach without validation had 92.4%accuracy,94.3%precision,and 91.1%recall.Validation showed 90%accuracy,91.2%precision,and 89.7%recall.Note that both algorithms outperform the rest.The paper presents that bispectrum-based nonlinear analysis using deep learning models outperforms standard machine learning methods and other deep learning methods based on convolutional architecture.They offered the best inference performance as the proposed approach improves categorization and prediction.Several instances show successful multi-class prediction in molecular biology’s massive data.
文摘Liver transplantation (LT) recipients are known to require less anesthetic agents. Providing minimally required anesthetics while avoiding awareness is especially important in LT recipients because it would help manage perioperative hemodynamic instability with less vasopressor and fast track recovery. This study aims to compare state entropy (SE) against bispectral index (BIS) during isoflurane anesthesia in LT. We adjusted anesthesia to BIS values 40 - 60, and compared it with concomitant SE values. BIS, SE values, and anesthetic requirements according to liver failure severity, etiology and LT stages were analyzed. For BIS-SE differences, SE value that is different from the concomitant BIS by more than 15 was defined as a significant disagreement. Mann Whitney, Kruskal Wallis test and a Poisson exact test were used for analysis. The BIS-SE pair sets of 2895 from 38 patients were analyzed. BIS, SE values and anesthetic requirements were significantly lower in MELD ≥ 20 (p < 0.001 in all) and in alcoholic etiology (p < 0.001 in all). For BIS-SE differences, 320 disagreement data pairs were seen at a rate of 1.33 times/hr (95% CI = [1.19, 1.48], p < 0.001). A significant disagreement was delineated in MELD score ≥ 20 (3.04 times/hr, CI = [2.64, 3.49], p < 0.001), alcoholic etiology (3.19 times/hr, [2.67, 3.78], p < 0.001) and postreperfusion stage (1.63 times/hr, [1.43, 1.85], p < 0.001). In these significant BIS-SE differences, 95.9% (307/320 disagreement data pairs) showed higher BIS than SE. In conclusion, in high MELD and alcoholic etiology, anesthetic requirements were significantly less, and BIS and SE showed great discrepancy with lower SE values. Therefore, when SE monitoring is used during LT, anesthesiologists may need to consider that in high MELD and alcoholic etiology, SE tends to show lower values than the concomitant BIS values that are within optimal anesthetic depth ranges.
文摘<b><span style="font-family:Verdana;">Background:</span></b><span style="font-family:Verdana;"> The bispectral index (BIS) derived from the electroencephalogram is an additional means of monitoring the depth of narcosis.</span><span style="font-family:Verdana;"> </span><b><span style="font-family:Verdana;">Objective:</span></b><span style="font-family:Verdana;"> To compare the monitoring of the depth of narcosis by the BIS associated with clinical data versus standard monitoring at the University Hospital of Parakou in Benin in 2019.</span><span style="font-family:Verdana;"> </span><b><span style="font-family:Verdana;">Methods:</span></b><span style="font-family:Verdana;"> This was an observational study for descriptive and analytical purposes with prospective data collection, carried out in general surgery and intensive care unit for 4 months. The inclusion criteria were: an age ≥ 18 years, an ASA score ≤ 3, surgery under general anesthesia and informed consent of the patient. Two groups were formed: non-BIS group monitored by clinical parameters (PA, FC, FR, EtCO</span><sub><span style="font-family:Verdana;vertical-align:sub;">2</span></sub><span style="font-family:Verdana;">, and SpO</span><sub><span style="font-family:Verdana;vertical-align:sub;">2</span></sub><span style="font-family:Verdana;">) only and BIS group monitored by bispectral index in addition to clinical parameters. Patients were seen 48 hours after the procedure.</span><span style="font-family:Verdana;"> </span><b><span style="font-family:Verdana;">Results:</span></b><b><span style="font-family:Verdana;"> </span></b><span style="font-family:Verdana;">36 patients were collected. The mean age was 40.63 ± 16.77 years with a sex ratio of 3. ASA 1 patients represented 86.11% of the sample and ASA2 patients 13.89%. The average doses of Propofol were not significantly reduced in the BIS group (p = 0.555). On the other hand, the period of intraoperative recovery (p-value = 0.007) and the NVPO (p = 0.043;OR = 0.10;95% CI [0.01 - 0.97]) were significantly reduced by the use of BIS. One case of intraoperative memorization (2.78%) was however found in the BIS group.</span><span style="font-family:Verdana;"> </span><b><span style="font-family:Verdana;">Conclusion:</span></b><span style="font-family:Verdana;"> The bispectral index makes it possible to significantly reduce the risk of intraoperative awakening and PONV, and not significantly reduce the consumption of Propofol.</span>
文摘In order to evaluate the accuracy of bispectral estimation method, signals of cosine function were adopted. Because the cosine signals’ three order moment spectrum and three order cumulant spectrum are zero, Non zero part of the bispectrum estimated by no matter which method is the estimation error. Through the comparison of three kinds of estimation methods: the direct method, indirect method and AR parameter method, errors of various estimation methods were obtained, then changing the values of different parameters in all methods, and observing the bispectral error values changes with the parameters, so as to provide a basis for the various bispectrum estimation method and the selection.
基金Shaanxi Creative Talents Promotion PlanTechnological Innovation Team(2023-CX-TD-48)Natural Science Foundation of Shaanxi Province(2024JC-YBMS-462,2024JC-YBMS-504)National Natural Science Foundation of China(52272101,62201609,62101588)。
文摘With the rapid development of detection technology and artificial intelligence,the widespread use of multispectral detectors has increased challenges to stealth capabilities.This paper presents a bispectral camouflage metasurface with microwave diffuse emission and tunable infrared(IR)emissivity,achieving an integrated design for radar cross-section(RCS)reduction and tunable IR emissivity.The structure consists of layers from bottom to top:aerogel felt,indium-tin-oxide(ITO),air,polyethylene terephthalate(PET),and ITO.It reduces RCS through microwave diffuse reflection and adjusts IR emissivity by controlling the ITO fill ratio.Both simulations and experiments demonstrate effective suppression of electromagnetic(EM)wave backscattering within4.5-10.3 GHz,achieving radar invisibility.The tunable IR emissivity ranges from 0.2 to 0.7 with good thermal insulation.This design alleviates issues related to structural thickness and processing complexity and avoids increased thermal load from microwave absorption,offering better tunable IR emissivity for various thermal camouflage environments.This metasurface holds significant promise for multispectral stealth and IR camouflage applications.
基金supported by the National Natural Science Foundation of China(Nos.62305220 and 92050202)the Shanghai Sailing Program(No.23YF1429300).
文摘Imaging through scattering media remains a formidable challenge in optical imaging.Exploiting the memory effect presents new opportunities for non-invasive imaging through the scattering medium by leveraging speckle correlations.Traditional speckle correlation imaging often utilizes a random phase as the initial phase,leading to challenges such as convergence to incorrect local minima and the inability to resolve ambiguities in object orientation.Here,a novel method for high-quality reconstruction of single-shot scattering imaging is proposed.By employing the initial phase obtained from bispectral analysis in the subsequent phase retrieval algorithm,the convergence and accuracy of the reconstruction process are notably improved.Furthermore,a robust search technique based on an image clarity evaluation function successfully determines the optimal reconstruction size.The study demonstrates that the proposed method can obtain high-quality reconstructed images compared with the existing scattering imaging approaches.This innovative approach to non-invasive single-shot imaging through strongly scattering media shows potential for applications in scenarios involving moving objects or dynamic scattering imaging scenes.
文摘Importance:The closed-loop infusion system can automatically adjust and maintain the depth of anesthesia by using the propofol target-controlled infusion(TCI)model under the feedback guidance of the bispectral index(BIS).Objective:To evaluate the safety and superiority of closed-loop TCI of propofol guided by BIS during maintenance of generalized intravenous anesthesia for preschool children.Methods:A total of 120 children aged 1–6 years were enrolled and were divided into a closed-loop feedback group(Group C)and an open-loop manual control group(Group O),with 60 participants in each group.For anesthesia maintenance,the propofol infusion rate was adjusted by the injection system under the guidance of BIS in Group C and was manually adjusted by anesthesiologists according to the BIS and clinical experience in Group O,to maintain a BIS level of 50.The time ratio of adequate anesthesia(40≤BIS≤60),light anesthesia(BIS>60),and deep anesthesia(BIS<40)were recorded.Results:A total of 119 patients(59 in Group C and 60 in Group O)were enrolled in the study.Group C demonstrated a higher time ratio of adequate anesthesia(P=0.014)compared to Group O.The time ratio of light anesthesia and the global score was lower in Group C than in Group O(P=0.010,P=0.015,respectively).The frequency of adjustment per unit of time was higher in Group C for propofol(P<0.001),while it was lower for remifentanil(P=0.010).Interpretation:BIS-guided closed-loop infusion of propofol is safe and effective for preschool children.The depth of anesthesia is controlled more accurately and smoothly.
文摘Background Awareness is a serious complication of general anesthesia. In China, the incidence of intraoperative awareness was 1% in patients undergoing total intravenous anesthesia （TIVA）. In this study, we compared the incidence of awareness between Bispectral index （BIS）-guided and routine TIVA protocol and evaluated the effect of BIS on preventing awareness. Methods A prospective, randomized, double-blinded, multicenter controlled trial was performed. Patients （〉18 years of age） undergoing TIVA were randomly divided into BIS-guided group （Group A, BIS was monitored and recommended to maintain between 40-60） and control group （Group B, BIS was monitored but the screen was covered）. The intraoperative BIS values were downloaded and the BIS trends of confirmed awareness cases were analyzed to determine whether light anesthesia existed. Results Of the total 5228 patients, 2919 patients were assigned to Group A and 2309 to Group B. Four cases of confirmed awareness （0.14%） were reported in the BIS-guided group and 15 （0.65%） in the control group （P=-0.002, OR=0.21, 95% confidence intervals： 0.07-0.63）. The incidence of possible awareness （0.14% vs. 0.26%, P=0.485） and dreaming （3.1% vs. 3.1%, P=0.986） was comparable between BIS-guided group and the control group. Among the 19 confirmed awareness cases, intraoperative BIS trends of six cases were downloaded and identified. Five of them showed signs of light anesthesia as BIS 〉60 and lasted 19-106 minutes, whereas one case had a stable BIS trend and the values were within 60 during the operation. Another five awareness cases were reviewed for anesthesia procedures, of which improper light anesthesia were confirmed. Conclusions BIS-guided TIVA （BIS was recommended to maintain between 40-60） decreased the risk of awareness compared with routine TIVA. The main reason for awareness was light anesthesia.
文摘Background Wavelet index （WLI） is a new parameter for monitoring depth of anesthesia based on Wavelet analysis. We observed the change of WLI and bispectral index （BIS） in patients regain of consciousness （ROC） in the absence of frontalis electromyographic （EMG） interference. The aim of this study was to compare the ability of WLI and BIS for reflecting ROC in patients undergone surgery. Methods Twelve patients who were scheduled for maxillofacial surgeries were enrolled in the study. BIS and WLI values were monitored continually. After being given midazolam and remifentanil, patients were asked to squeeze the investigator＇s hand ever 30 seconds. Patients were continuously given propofol until loss of consciousness （LOC1）. Tunstalrs isolated forearm technique was used to test the surgical consciousness in patients. After total muscle relaxation endotracheal intubations were performed, and the patients were connected to a ventilator. Then, propofol was withdrawn until the patients showed regain of consciousness （ROC1） and an awareness reaction. After the command test, patients were readministered with propofol until loss of consciousness （LOC2）. After surgery, all of the sedatives were withdrawn, and the patients were let to regain consciousness （ROC2）, Results The BIS values of twelve patients at ROC1 after using muscle relaxant were much lower than those at LOC1 and ROC2 without using muscle relaxant, showing statistical significance （P 〈0.05）. Meanwhile, the WLI values of twelve patients at ROC1 after using muscle relaxant were much higher than those at LOC1 and equal to ROC2 without using muscle relaxant, showing statistical significances （P 〈0.05） between ROC1 and LOCI. Conclusions This study showed that under muscle relaxation or facial paralysis, when there is no EMG signal, BIS can not accurately reflect regain of consciousness in surgical patients, but WLI can reflect it accurately. So WLI may have advantages for reflecting state of consciousness in surgical patients.
