Objective:We aimed to develop a novel visualized model based on nomogram to predict postoperative overall survival.Methods:This was a multicenter, retrospective, observational cohort study, including participants with histologically confirmed gastric and colorectal cancer who underwent radical surgery from 11 medical centers in China from August 1, 2015 to June 30, 2018. Baseline characteristics, histopathological data and nutritional status, as assessed using Nutrition Risk Screening 2002 (NRS 2002) score and the scored Patient-Generated Subjective Global Assessment, were collected. The least absolute shrinkage and selection operator regression and Cox regression were used to identify variables to be included in the predictive model. Internal and external validations were performed.Results:There were 681 and 127 patients in the training and validation cohorts, respectively. A total of 188 deaths were observed over a median follow-up period of 59 (range: 58 to 60) months. Two independent predictors of NRS 2002 and Tumor-Node-Metastasis (TNM) stage were identified and incorporated into the prediction nomogram model together with the factor of age. The model's concordance index for 1-, 3- and 5-year overall survival was 0.696, 0.724, and 0.738 in the training cohort and 0.801, 0.812, and 0.793 in the validation cohort, respectively.Conclusions:In this study, a new nomogram prediction model based on NRS 2002 score was developed and validated for predicting the overall postoperative survival of patients with gastric colorectal cancer. This model has good differentiation, calibration and clinical practicability in predicting the long-term survival rate of patients with gastrointestinal cancer after radical surgery.

Objective:To investigate the application effect of early awake prone position in mild-to-moderate acute respiratory distress syndrome (ARDS) patients, and analyze the related factors affecting the prone position outcome.Methods:A prospective cohort study was conducted. The mild-to-moderate ARDS patients admitted to the emergency department of Yingshang County People's Hospital from January 2020 to June 2023 were enrolled as the research subjects. According to the results of prone tolerance test, the patients were divided into awake prone position group and non-prone position group. All patients were given high flow nasal cannula (HFNC) according to the standard procedures. The patients in the awake prone position group received prone position treatment within 12 hours after admission, in addition to the standard treatment. This could be performed in several times, at least once a day, and at least 2 hours each time. In order to prolong the prone position as much as possible, the patients were allowed to move or keep a small angle side prone. The changes of oxygenation index (PaO 2/FiO 2) at 0, 24, 48, and 72 hours after admission, the rate of intensive care unit (ICU) transfer, the use rate and use time of non-invasive ventilation (NIV), the total hospital stay, and the daily prone position time and 2-hour ROX index [ratio of pulse oxygen saturation/fraction of inspired oxygen (SpO 2/FiO 2) and respiratory rate (RR)] of prone position patients were recorded. The successful termination of HFNC was defined as the successful prone position, and the failure of prone position was defined as switching to NIV or transferring to ICU. Subgroup analysis was performed, and the binary multivariate Logistic regression analysis was used to screen the influencing factors of the early awake prone position outcome. Results:A total of 107 patients were finally enrolled, with 61 in the awake prone position group and 46 in the non-prone position group. Both groups showed a gradual increase in PaO 2/FiO 2 with prolonged admission time. The PaO 2/FiO 2 at 24 hours after admission in the awake prone position group was significantly higher than that at 0 hour [mmHg (1 mmHg ≈ 0.133 kPa): 191.94±17.86 vs. 179.24±29.27, P < 0.05], while the difference in the non-prone position group was only statistically significant at 72 hours (mmHg: 198.24±17.99 vs. 181.24±16.62, P < 0.05). Furthermore, the PaO 2/FiO 2 at 48 hours and 72 hours after admission in the awake prone position group was significantly higher than that in the non-prone position group. The use rate of NIV in the awake prone position group was significantly lower than that in the non-prone position group [36.1% (22/61) vs. 56.5% (26/46), P < 0.05]; Kaplan-Meier curve analysis further confirmed that the patients in the awake prone position group used NIV later, and the cumulative rate of NIV usage was significantly lower than that in the non-prone position group (Log-Rank test: χ2 = 5.402, P = 0.020). Compared with the non-prone position group, the ICU transfer rate in the awake prone position group was significantly lowered [11.5% (7/61) vs. 28.3% (13/46), P < 0.05], and the HFNC time, NIV time, and total hospital stay were significantly shortened [HFNC time (days): 5.71±1.45 vs. 7.24±3.36, NIV time (days): 3.27±1.28 vs. 4.40±1.47, total hospital stay (days): 11 (7, 13) vs. 14 (10, 19), all P < 0.05]. Of the 61 patients who underwent awake prone positioning, 39 were successful, and 22 failed. Compared with the successful group, the patients in the failure group had a higher body mass index [BMI (kg/m 2): 26.61±4.70 vs. 22.91±5.50, P < 0.05], lower PaO 2/FiO 2, proportion of asymptomatic hypoxemia and 2-hour ROX index of prone position [PaO 2/FiO 2 (mmHg): 163.73±24.73 vs. 185.69±28.87, asymptomatic hypoxemia proportion: 18.2% (4/22) vs. 46.2% (18/39), 2-hour ROX index of prone position: 5.75±1.18 vs. 7.21±1.45, all P < 0.05], and shorter daily prone positioning time (hours: 5.87±2.85 vs. 8.05±1.99, P < 0.05). Binary multivariate Logistic regression analysis showed that all these factors were influencing factors for the outcome of awake prone positioning (all P < 0.05), among which BMI [odds ratio ( OR) = 1.447, 95% confidence interval (95% CI) was 1.105-2.063] and non-asymptomatic hypoxemia ( OR = 13.274, 95% CI was 1.548-117.390) were risk factors for failure of prone position, while PaO 2/FiO 2 ( OR = 0.831, 95% CI was 0.770-0.907), daily prone positioning time ( OR = 0.482, 95% CI was 0.236-0.924), and 2-hour ROX index of prone position ( OR = 0.381, 95% CI was 0.169-0.861) were protective factors. Conclusions:Early awake prone positioning in patients with mild-to-moderate ARDS supported by HFNC is safe and feasible, reducing the use rate and duration of NIV, lowering the ICU transfer rate, and shortening the hospital stay. High BMI and non-asymptomatic hypoxemia are risk factors for failed prone position, while higher PaO 2/FiO 2 and the ROX index within 2 hours of prone position (the patient's good response to prone position), and prolonged daily prone position can improve the success rate of prone position.

Objective To investigate the effect of transcranial alternating current stimulation(tACS)on cerebral blood flow(CBF)in patients with Alzheimer's disease(AD).Methods A ret-rospective study was conducted on 21 mild AD patients admitted in our hospital from September 2019 to April 2022.All of them received tACS treatment for 3 weeks.Mini-mental state examina-tion(MMSE),auditory verbal learning test(AVLT)and MRI were applied to obtain the data at baseline(T0),the end of the treatment(T1)and in three months after treatment(T2).Z-trans-form CBF(zCBF)was performed to reduce individual variability.The changes in MMSE and AVLT scores,as well as brain zCBF and CBF values before and after tACS treatment were ana-lyzed.Spearman correlation analysis was used to examine the relationship of zCBF and CBF with cognitive scores.Results In the AD patients,their MMSE score was significantly increased at T1 than at T0[22.00(20.00,25.00)vs 20.00(18.00,21.50),P＜0.01].Based on voxel analysis,the AD patients exhibited significantly increased zCBF in the bilateral frontal and temporal cortex at T1,and in the right frontal and temporal cortex at T2 when compared with the levels at T0(P＜0.05).The most pronounced increase in zCBF was observed in the right insular.Based on region of inter-est analysis,increased zCBF and CBF in the right frontal and temporal cortex at T1 were observed(P＜0.05).There was a positive correlation between the change of CBF in the right frontal cortex and AVLT-recognition recall at T1(r=0.617,P=0.005)and between the change of CBF in the left frontal cortex and MMSE at T2(r=0.596,P=0.012).Conclusion MRI 3D-ASL can objec-tively evaluate the changes of CBF in AD patients after tACS treatment,and it provides a reliable imaging marker for evaluating the efficacy of tACS.

Objective:To evaluate the safety and efficacy of enhanced recovery after surgery(ERAS) in the perioperative period of congenital choledochal cysts in children.Methods:This is a multicenter prospective randomized controlled study. The clinical data of 273 pediatric congenital choledochal cysts(CCC) patients who underwent surgery at 14 medical centers with complete follow-up data were collected through the medical data analysis platform. Among them, 123 cases in ERAS group were managed perioperatively in strict accordance with ERAS mode, and 150 cases in conventional group were managed according to traditional mode. The length of hospital stay,time to first farting, time to complete feeding, the incidence of complications, cost and readmission rate within 30 days,stress indexes and liver function were compared between the two groups.Results:Compared with the conventional group, median time to start farting (2.0 d vs. 3.0 d, P<0.001), median time to complete feeding (5.0 d vs. 7.0 d, P<0.001), median postoperative hospitalization time (6.0 d vs. 9.0 d, P<0.001),the median total length of stay(13.0 d vs. 15.0 d, P<0.001) were shorter,the median hospitalization cost (37,000 yuan vs.43,000 yuan P<0.001) was lower, and stress indexes recovered quickly. The incidence of postoperative hospital stay and readimission rate within 30 d were not statistically different between the two groups. Conclusion:It is safe and feasible to implement ERAS for children with CCC in the perioperative period, which can reduce stress response, speed up recovery,and save medical costs.

Objective:To investigate the early clinical characteristics of elderly patients with severe burns and the risk factors on prognosis.Methods:This study was a retrospective case series study. Clinical data of 124 elderly patients with severe burns who met the inclusion criteria and were admitted to the 12 hospitals from January 2015 to December 2020 were collected, including 4 patients from the Fourth People's Hospital of Dalian, 5 patients from Fujian Medical University Union Hospital, 22 patients from Guangzhou Red Cross Hospital of Jinan University, 5 patients from Heilongjiang Provincial Hospital, 27 patients from the First Affiliated Hospital of Naval Medical University, 9 patients from the First Affiliated Hospital of Nanchang University, 10 patients from Affiliated Hospital of Nantong University, 9 patients from Tongren Hospital of Wuhan University & Wuhan Third Hospital, 12 patients from the 924 th Hospital of PLA, 6 patients from Zhangjiagang First People's Hospital, 4 patients from Taizhou Hospital of Zhejiang Province, and 11 patients from Zhengzhou First People's Hospital. The patients' overall clinical characteristics, such as gender, age, body mass index, total burn area, full-thickness burn area, inhalation injury, causative factors, whether combined with underlying medical diseases, and admission time after injury were recorded. According to the survival outcome within 28 days after injury, the patients were divided into survival group (89 cases) and death group (35 cases). The following data of patients were compared between the two groups, including the basic data and injuries (the same as the overall clinical characteristics ahead); the coagulation indexes within the first 24 hours of injury such as prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time, D-dimer, fibrinogen degradation product (FDP), international normalized ratio (INR), and fibrinogen; the blood routine indexes within the first 24 hours of injury such as white blood cell count, platelet count, neutrophil-to-lymphocyte ratio, monocyte count, red blood cell count, hemoglobin, and hematocrit; the organ function indexes within the first 24 hours of injury such as direct bilirubin, total bilirubin, urea, serum creatinine, aspartate aminotransferase, alanine aminotransferase, total protein, albumin, globulin, blood glucose, triglyceride, total cholesterol, alkaline phosphatase, creatine kinase, electrolyte indexes (potassium, sodium, chlorine, calcium, magnesium, and phosphorus in blood), uric acid, myoglobin, and brain natriuretic peptide; the infection and blood gas indexes within the first 24 hours of injury such as procalcitonin, C-reactive protein, pH value, oxygenation index, base excess, and lactate; treatment such as whether conducted with mechanical ventilation, whether conducted with continuous renal replacement therapy, whether conducted with anticoagulation therapy, whether applied with vasoactive drugs, and fluid resuscitation. The analysis was conducted to screen the independent risk factors for the mortality within 28 days after injury in elderly patients with severe burns. Results:Among 124 patients, there were 82 males and 42 females, aged 60-97 years, with body mass index of 23.44 (21.09, 25.95) kg/m 2, total burn area of 54.00% (42.00%, 75.00%) total body surface area (TBSA), and full-thickness burn area of 25.00% (10.00%, 40.00%) TBSA. The patients were mainly combined with moderate to severe inhalation injury and caused by flame burns. There were 43 cases with underlying medical diseases. The majority of patients were admitted to the hospital within 8 hours after injury. There were statistically significant differences between patients in the 2 groups in terms of age, total burn area, full-thickness burn area, and inhalation injury, and PT, APTT, D-dimer, FDP, INR, white blood cell count, platelet count, urea, serum creatinine, blood glucose, blood sodium, uric acid, myoglobin, and urine volume within the first 24 hours of injury (with Z values of 2.37, 5.49, 5.26, 5.97, 2.18, 1.95, 2.68, 2.68, 2.51, 2.82, 2.14, 3.40, 5.31, 3.41, 2.35, 3.81, 2.16, and -3.82, respectively, P<0.05); there were statistically significant differences between two groups of patients in whether conducted with mechanical ventilation and whether applied with vasoactive drugs (with χ2 values of 9.44 and 28.50, respectively, P<0.05). Age, total burn area, full-thickness burn area, serum creatinine within the first 24 hours of injury, and APTT within the first 24 hours of injury were the independent risk factors for the mortality within 28 days after injury in elderly patients with severe burns (with odds ratios of 1.17, 1.10, 1.10, 1.09, and 1.27, 95% confidence intervals of 1.03-1.40, 1.04-1.21, 1.05-1.19, 1.05-1.17, and 1.07-1.69, respectively, P<0.05). Conclusions:The elderly patients with severe burns had the injuries mainly from flame burns, often accompanied by moderate to severe inhalation injury and enhanced inflammatory response, elevated blood glucose levels, activated fibrinolysis, and impaired organ function in the early stage, which are associated with their prognosis. Age, total burn area, full-thickness burn area, and serum creatinine and APTT within the first 24 hours of injury are the independent risk factors for death within 28 days after injury in this population.

Objective:To investigate the impact of the early infusion rate on prognosis and the factors of influencing the infusion rate in patients with severe burns and inhalation injury.Methods:This study was a retrospective case series research. From January 2015 to December 2020, 220 patients with severe burns and inhalation injury meeting the inclusion criteria were admitted to 7 burn treatment centers in China, including 13 cases in the Fourth People's Hospital of Dalian, 26 cases in the First Affiliated Hospital of Naval Medical University, 73 cases in Guangzhou Red Cross Hospital of Jinan University, 21 cases in the 924 th Hospital of PLA, 30 cases in the First Affiliated Hospital of Jiangxi Medical College of Nanchang University, 30 cases in Tongren Hospital of Wuhan University & Wuhan Third Hospital, and 27 cases in Zhengzhou First People's Hospital. There were 163 males and 57 females, and their ages ranged from 18 to 91 years. The patients were divided into survival group and death group according to the survival within 28 d post injury. The following data of patients in the 2 groups were collected, including basic information (gender, age, body weight, body temperature, etc.), the injury characteristics (total burn area, post-injury admission time, etc.), the underlying diseases, the post-injury fluid resuscitation condition (infusion rate and ratio of infused electrolyte solution to colloid solution in the first 24 h post injury, etc.), the results of laboratory tests on admission (blood urea nitrogen, blood creatinine, albumin, pH value, base excess, blood lactate, oxygenation index, etc.), and treatment condition (inhaled oxygen volume fraction, hospitalization day, renal replacement therapy, etc.). After adjusting covariates using univariate Cox regression analysis, the multivariate Cox regression analysis was performed to evaluate the impact of infusion rate in the first 24 h post injury on patient death. The receiver operator characteristic curve for the infusion rate in the first 24 h post injury to predict the risk of death was plotted, and the maximum Youden index was calculated. Patients were divided into 2 groups according to the cutoff value (2.03 mL·kg -1·% total body surface area (TBSA) -1) for predicting risk of death by the infusion rate in the first 24 h post injury determined by the maximum Youden index, and the risk of death was compared between the 2 groups. The correlation between the previously mentioned clinical data and the infusion rate in the first 24 h post injury was analyzed; after the univariate linear regression analysis was used to screen the independent variables, the multivariate linear regression analysis was performed to screen the independent influential factors on the infusion rate in the first 24 h post injury. Results:Compared with those in survival group, patients in death group had significantly higher age and total burn area (with Z values of 12.08 and 23.71, respectively, P<0.05), the infusion rate in the first 24 h post injury, inhaled oxygen volume fraction, and blood urea nitrogen, blood creatinine, blood lactic acid on admission (with Z values of 7.99, 4.01, 11.76, 23.24, and 5.97, respectively, P<0.05), and the proportion of patients treated with renal replacement therapy ( P<0.05) were significantly higher, the albumin, pH value, and base excess on admission were significantly lower ( t=2.72, with Z values of 8.18 and 9.70, respectively, P<0.05), and the hospitalization day was significantly reduced ( Z=85.47, P<0.05). After adjusting covariates, the infusion rate in the first 24 h post injury was the independent influential factor on death (with standardized hazard ratio of 1.69, 95% confidence interval of 1.21-2.37, P<0.05). Patients in infusion rate ≥2.03 mL·kg -1·%TBSA -1 group had a significantly higher risk of death than those in infusion rate <2.03 mL·kg -1·% TBSA -1 group (with hazard ratio of 3.47, 95% confidence interval of 1.48-8.13, P<0.05). There was a significant correlation between total burn area, body weight, inhaled oxygen volume fraction, body temperature, post-injury admission time, the ratio of infused electrolyte solution to colloid solution in the first 24 h post injury, and oxygenation index <300 on admission and the infusion rate in the first 24 h post injury (with r values of -0.192, -0.215, 0.137, -0.162, -0.252, and 0.314, respectively, Z=4.48, P<0.05). After screening the independent variables, total burn area, body weight, post-injury admission time, and oxygenation index <300 on admission were the independent influential factors on the infusion rate in the first 24 h post injury (with standardized β values of -0.22, -0.22, -0.19, and 0.46, respectively, 95% confidence intervals of -0.34 to 0.09, -0.34 to 0.10, -0.32 to 0.06, and 0.22 to 0.71, respectively, P<0.05). Conclusions:The infusion rate in the first 24 h post injury in patients with severe burns and inhalation injury is the independent factor of influencing death, and patients with infusion rate ≥2.03 mL·kg -1·%TBSA -1 in the first 24 h post injury have a significantly increased risk of death. The total burn area, body weight, post-injury admission time, and oxygenation index <300 on admission were the independent factors of influencing the infusion rate in the first 24 h post injury in patients with severe burns and inhalation injury.

Objective:To assess the predictive value of dosiomics in predicting the occurrence of bone marrow suppression (BMS) in patients with pelvic tumors during radiotherapy.Methods:A retrospective analysis was conducted on the clinical data and radiotherapy planning documents of 129 patients with pelvic region tumors who underwent radiotherapy at the First Affiliated Hospital of Nanjing Medical University from January 2019 to January 2023. The region of interest (ROI) was outlined for bone marrow in the pelvic region by Accu Contour software in planning CT, and the ROI was exported together with the dose distribution file. According to a stratified randomization grouping method, the patients were divided into the training set and test set in an 8 vs. 2 ratio. The dosiomic features were extracted from the ROI, and the two independent samples t-test and the least absolute shrinkage and selection operator (LASSO) algorithm was employed to identify the best predictive characteristics. Subsequently, the dosiomic scores were calculated. Clinical predictors were identified through both univariant and multivariate logistic regression analyses. Predictive models were constructed by using clinical predictors alone and combining clinical predictors and dosiomic scores. The efficacy of predictive model was assessed by plotting the receiver operating characteristic (ROC) curve and evaluating its performance through the area under the ROC curve (AUC), the calibration curve, and decision curve analysis (DCA). Results:Fourteen dosiomic features that showed a strong correlation with the occurrence of BMS were screened and utilized to calculate the dosiomic scores. Based on both univariant and multivariate logistic regression analyses, chemotherapy, planning target volume (PTV) and V 5 Gy were identified as clinical predictors. According to the combined model, the AUC values for the training set and test set were 0.911 and 0.868, surpassing those of the clinical model (AUC=0.878 and 0.824). Furthermore, the analysis of both the calibration curve and DCA suggested that the combined model had higher calibration and net clinical benefit. Conclusion:The combined model has a high diagnostic value for predicting BMS in patients with pelvic tumors during radiotherapy.

Objective: To investigate the awareness of hepatitis C prevention and control knowledge and its influencing factors among female sex workers (FSWs) in Jiaxing City, Zhejiang Province. Methods: According to the HIV/AIDS Sentinel Surveillance Plan, FSWs at ages of 15 to 65 years monitored by the national AIDS surveillance sentinel in Jiaxing City were recruited, and demographic information, awareness of hepatitis C prevention and control knowledge and related behaviors were collected by questionnaire surveys. Factors affecting the awareness of hepatitis C prevention and control knowledge were identified by a multivariable logistic regression model. Results: A total of 430 questionnaires were allocated, and 412 were valid, with an effective rate of 95.81%. The respondents had a mean age of (28.58±4.93) years, and included 258 unmarried FSWs (62.62%), 344 with registered residence outside Zhejiang Province (83.50%), 212 with junior high school education or below (51.46%) and 243 from high-end entertainment places (58.98%). The overall awareness of hepatitis C prevention and control knowledge among FSWs was 20.39%, and the awareness of "Transfusion of blood containing hepatitis C virus may acquire hepatitis C" (38.83%) and the awareness of "tattooing, eyebrow tattooing and ear piercing in streets or small shops may infect hepatitis C" (38.11%) were relatively low. Multivariable logistic regression analysis identified marital status (divorced or widowed, OR=0.161, 95%CI: 0.054-0.482), educational level (high school or technical secondary school, OR=2.568, 95%CI: 1.446-4.560; junior college or above, OR=6.110, 95%CI: 2.658 -14.045) and grade of entertainment places (high-end entertainment places, OR=2.756, 95%CI: 1.525-4.982) as factors affecting the awareness of hepatitis C prevention and control knowledge among FSWs. Conclusion FSWs in Jiaxing City have a low awareness of hepatitis C prevention and control knowledge, especially lacking of knowledge about the transmission routes and prognosis of hepatitis C.

Diabetic gastroparesis （DGP） is a common diabetic neuropathy that affects the normal function of gastric motility and emptying. Clinically， it often manifests as abdominal distension， nausea and vomiting， early satiety， dyspepsia， etc. The pathogenesis of DGP is multifactorial， closely related to many factors， such as chronic hyperglycemia， neuropathy， autonomic nervous system disorders， inflammation， and oxidative stress. These factors can interact with each other， leading to delayed gastric emptying and the occurrence of related symptoms. Traditional Chinese medicine （TCM） has significant advantages in the prevention and treatment of DGP， including a long history， remarkable efficacy， individualized treatment， diverse therapeutic formulations， and improvement in the quality of life. Additionally， TCM is known for its low adverse reactions， good tolerance， and multi-targeted effects， making it an important approach in the management of DGP. Previous research has found that the main mechanisms of Chinese medicine in the prevention and treatment of DGP include the regulation of gastrointestinal hormones， inhibition of inflammatory responses， reduction of oxidative stress， enhancement of interstitial cells of Cajal activity， inhibition of pyroptosis， and modulation of related signaling pathways such as stem cell factor （SCF）/cellular growth factor receptor （c-Kit）， adenosine monophosphate-activated protein kinase （AMPK）， Ras homologous genome member A （RhoA）/Rho-associated coiled-coil forming kinase （ROCK）. This article primarily summarized the research progress on Chinese medicine in preventing and treating DGP through the inhibition of inflammatory responses， reduction of oxidative stress， enhancement of interstitial cells of Cajal activity， inhibition of pyroptosis， and regulation of related signaling pathways， aiming to provide a reference and basis for further research on the application value of Chinese medicine in the prevention and treatment of DGP.

Flubromazolam(Flub)is a novel psychoactive substance of benzodiazepines and the mechanism underlying its addiction still remains elusive.This study investigated the reward effect of Flub using conditioned place preference(CPP)mouse model.The neuronal activity was evaluated by c-Fos expression,and the neural circuit was tracked by virus tracing.This study also investigated the regulatory effect of neural circuits on Flub-induced reward effects through chemogenetic approach.The results showed that,at the dose of 3 mg/kg,Flub significantly increased CPP score and c-Fos expression in dopaminergic(DA)neurons of ventral tegmental area(VTA).Inhibition of VTA dopaminergic neuron activity dramatically decreased Flub-induced CPP score.Virus tracing verified GABAergic neuronal projection of medial rostrum tegmental nucleus(RMTg)to VTA dopaminergic neurons.Activation of RMTgGABA→VTADA circuit or blockade of benzodiazepine receptors(BZR)in RMTg significantly decreased Flub-induced CPP score.These results indicate that Flub produced reward effect via BZR-mediated RMTgGABA→VTADA circuit.