Porous carbon-based robust, durable, and flexible electrochemical device for K+ detection in sweat.

Ion sensors are attracting attention for real-time ion monitoring in biological fluids, which requires the development of sensitive, stable, flexible, robust and durable ion-selective electrodes (ISEs) and reference electrodes (REs). In this paper, a highly robust and durable ion sensor was prepared by coating polymer membranes on porous carbon electrodes. A high sensitivity of 58.6 mV per decade with a rapid response time of 0.8 s, and a negligible potential drift less than 1.4 mV h-1 were obtained simultaneously. In addition, after six washing cycles, the K+ ion sensors still have an average sensitivity of 53.2 mV per decade. Importantly, the polymer membrane permeated and packed the porous structure tightly, and thus the ion sensors presented outstanding robustness and durability. The Nernst slope of the K+ ion response fluctuated from 60.2 to 57.9 mV per decade between 0° and 60° bending angles. Repeated bending for 8000 cycles did not result in the delamination of the sensing and reference membranes or reduction of the sensitivity (57.4 mV per decade). Furthermore, five kinds of flexible reference electrodes (LEC, bare Ag, bare Ag/AgCl, PVB + NaCl on Ag/AgCl, PVC/agarose + NaCl on Ag/AgCl) were fabricated and evaluated in terms of the sensitivity for Cl- and long-term stability. Finally, the flexible K+ ion sensor was integrated with microfluidic channels and connected to a portable electrochemical workstation to realize the real-time analysis of human sweat.

The role of proactive behavior on COVID-19 infordemic in the Chinese Sina-Microblog: a modeling study.

In order to avoid forming an information cocoon, the information propagation of COVID-19 is usually created through the action of "proactive search", an important behavior other than "reactive follow". This behavior has been largely ignored in modeling information dynamics. Here, we propose to fill in this gap by proposing a proactive-reactive susceptible-discussing-immune (PR-SFI) model to describe the patterns of co-propagation on social networks. This model is based on the forwarding quantity and takes into account both proactive search and reactive follow behaviors. The PR-SFI model is parameterized by data fitting using real data of COVID-19 related topics in the Chinese Sina-Microblog, and the model is calibrated and validated using the prediction accuracy of the accumulated forwarding users. Our sensitivity analysis and numerical experiments provide insights about optimal strategies for public health emergency information dissemination.

COVID-19 information contact and participation analysis and dynamic prediction in the Chinese Sina-microblog.

The outbreak of a novel coronavirus (COVID-19) aroused great public opinion in the Chinese Sina-microblog. To help in designing effective communication strategies during a major public health emergency, we analyze the real data of COVID-19 information and propose a comprehensive susceptible-reading-forwarding-immune (SRFI) model to understand the patterns of key information propagation considering both public contact and participation. We develop the SRFI model, based on the public reading quantity and forwarding quantity that denote contact and participation respectively, and take into account the behavior that users may re-enter another related topic during the attention phase or the participation phase freely. Data fitting using the real data of both reading quantity and forwarding quantity obtained from Chinese Sina-microblog can parameterize the model to make an accurate prediction of the COVID-19 public opinion trend until the next major news item occurs, and the sensitivity analysis provides the basic strategies for communication.

N,S-co-doped carbon dots for rapid acid test paper and bioimaging.

Fluorescent N,S-CDs with a quantum yield of 37.8% were synthesized via a one-pot solvothermal method. Detailed characterizations on physical, chemical and optical properties have been investigated. N,S-CDs demonstrated remarkably quenched and enhanced fluorescence in acidic and basic media. Direct qualitative analysis in pH sensor and cell imaging were preliminarily studied.

Microwave-assisted fabrication of copper-functionalized carbon quantum dots for sensitive detection of histidine.

Fluorescent carbon quantum dots are emerging as a new class of fluorescent probes due to their unique optical properties. Herein, we presented a simple, one-pot and effective preparation strategy for copper-functionalized carbon quantum dots (Cu-CDs). The Cu-CDs demonstrated excitation-independent emissions, high fluorescent quantum yield (~ 24.4%) and excellent fluorescent stability. The fluorescence of Cu-CDs could be quenched efficiently in the presence of histidine (His) due to the coordination occurring between surface Cu and imidazole side chains of His. Thus, the Cu-CDs could be used as an efficient fluorescent probe for His detection. Under optimal conditions, the fluorescent signals of Cu-CDs decreased linearly with the concentrations of His over a range of 0.1-15 µM. The detection limit was 30 nM. The proposed method provided obvious advantages of rapid response, convenience, simplicity, high selectivity and sensitivity. Moreover, good results also have been obtained for His detection in real biological fluid samples.

Effects of propofol intravenous injection bolus on the left ventricular function and the myocardial beta-adrenoceptor in rats.

Propofol bolus injection has been reported to influence cardiovascular functions. However, the detailed mechanism underlying this action has not been elucidated. This study was designed to investigate the effects of propofol i.v. bolus on the left ventricular function, the myocardial beta-adrenoceptor (beta-AR) binding-site density (Bmax) and Kd (apparent dissociation constant) in a 30-minute period. One hundred and four male Wistar rats were randomly divided into four groups: group C (control group), group I (intralipid group), group P1 (5 mg/kg propofol) and group P2 (10 mg/kg propofol). The results showed a significant downregulation of HR, LVSP, +dp/dtmax and -dp/dtmax in both groups P1 and P2 (especially after bolus injection in 7 min) than those of group C (P < 0.05), whereas no significant difference was found between the P1 and P2 groups (P > 0.05). Likely, Bmax was remarkably upregulated in both groups P1 and P2 (P < 0.05, vs. groups C and I), and there was no significant difference between these two groups (P > 0.05). Of note, the Kd value in group P2 (10 mg/kg propofol) was found dramatically increased in 30 min than that in the low-dose propofol-treated group (group P1) as well as in groups C and I (P < 0.05). In conclusion, these results indicate that intravenous injection of propofol bolus can inhibit the cardiac function partially via upregulation of Bmax and downregulation of the beta-AR affinity at higher-dose injection of propofol bolus.

[The comparative proteomic analysis of serum cytokine expression in acute lung injury patients in peri-operative stage of liver transplantation].

OBJECTIVE: To investigate the characteristics of serum cytokine expression in acute lung injury (ALI) patients in peri-operative stage of liver transplantation with the aim of setting the basis for screening the early markers and treatment targets of ALI. METHODS: Four male patients with ALI occurring in peri-operative stage of liver transplantation for hepatitis B liver cirrhosis, with no lung, renal, or brain abnormality, without difference in clinical findings (urine volume, blood loss, ascites, amount of blood transfusion, operation time, anhepatic time, the use of vaso-active drugs, diuretics and condition of circulation) were included for study. Blood was taken after anesthesia, 3 hours and 24 hours after new liver. RayBio human antibody array was used to analyze the cytokine expression. RESULTS: Compared with healthy people, in the patients with ALI in peri-operative stage of liver transplantation, upregulation of some cytokines appeared as early as after anesthesia, including interleukins (IL-3, IL-6, IL-12 p40, IL-12 p70), monocyte chemoattractant protein-2 (MCP-2), macrophage-colony stimulating factor (M-CSF), monokine induced by interferon-gamma (MIG), macro-phage inflammatory protein-1 alpha (MIP-1 alpha), soluble tumor necrosis factor receptor I (sTNFR I), especially sTNFR II which showed even stronger expression, while normal T cells expression and secretory factor (RANTES) and platelet-derived growth factor-BB (PDGF-BB) showed downregulation in expression. Some more cytokines showed upregulation in expression at neohepatic 3 hours, especially IL-12 p70, sTNFR I, sTNFR II showed upregulation, while RANTES, PDGF-BB and IL-1 alpha showed downregulation in expression. The number of cytokines showing upregulation was significantly increased at neohepatic 24 hours. Compared with those at neohepatic 3 hours, eotaxin, IL-1 alpha, IL-1 beta, IL-4, IL-15, MCP-2 showed significantly higher upregulation at neohepatic 24 hours, and among them IL-3 and IL-6 especially IL-2 showed even more upregulation in expression. CONCLUSION: There are changes in expression of different kinds of cytokines in various extent before operation, at neohepatic 3 hours and neohepatic 24 hours. Some of them may be considered as important early markers and treatment targets. Further researches with large samples would be necessary to elucidate the clinical implication.

[Changes in plasma S-100 beta and neuron-specific enolase in peri-operative period of orthotopic liver transplantation and its relationship with encephalopathy after operation].

OBJECTIVE: To observe the changes in plasma S-100 beta and neuron-specific enolase (NSE) and to study their relationship with encephalopathy after orthotopic liver transplantation (OLT). METHODS: Thirty patients without neurological disease undergoing OLT were studied. Plasma S-100 beta and NSE were examined at three time points: after induction of anesthesia (T1), at the end of operation (T2) and 24 hours after reperfusion of the transplant (T3). The difference of plasma S-100 beta and NSE between encephalopathy group and non-encephalopathy group was analyzed. RESULTS: Eleven patients were complicated with encephalopathy after OLT. In 30 patients, S-100 beta at T2 [(3.715+/-1.523) microg/L] was higher than that at T1 [(1.478+/-0.809) microg/L, P<0.01]; S-100 beta at T3 [(1.765+/-0.894) microg/L] decreased to normal level (T1). NSE at T2 [(26.684+/-7.973) microg/L] was higher than that at T1 [(14.012+/-4.612) microg/L, P<0.01]. At T3, the level of plasma NSE [(18.105+/-7.345) microg/L] was decreased, but higher than that at T1. Plasma S-100 beta and NSE in encephalopathy group (11 cases) and non-encephalopathy group (19 cases) showed the same tendency of change as all of the patients. Plasma S-100 beta at T3 in encephalopathy group [(2.007+/-0.854)microg/L] was higher than that in non-encephalopathy group [(1.468+/-0.903) microg/L, P<0.05], and it was correlated with the presence of encephalopathy (r=0.385, P=0.039), but not at T1 and T2. Plasma NSE at three time points showed no relationship to the presence of encephalopathy. CONCLUSION: The increase in plasma S-100 beta and NSE during OLT indicates the occurrence of damage to the brain. But plasma S-100 beta and NSE cannot predict encephalopathy after OLT.

Prognostic values of serum cystatin C and beta2 microglobulin, urinary beta2 microglobulin and N-acetyl-beta-D-glucosaminidase in early acute renal failure after liver transplantation.

BACKGROUND: Acute renal failure (ARF) after liver transplantation is associated with high mortality and morbidity. Early therapeutic or preventive intervention is hampered by the lack of early effective prognostic factors. Recent studies indicated that serum levels of cystatin C and beta2-microglobulin (beta2 MG) as well as urinary beta2 MG and N-acetyl-beta-D-glucosaminidase (NAG) would increase in patients with early and mild renal impairment. In this study, these factors were detected during the different stages in patients who accepted orthotopic liver transplantation (OLT), and their feasibilities to predict early ARF after OLT were also analyzed. METHODS: Sixty patients with normal blood urea nitrogen (BUN) and serum creatinine (SCr) who received modified piggyback liver transplantation without veno-venous bypass were prospectively studied. Blood samples were drawn from patients for the determination of serum beta2 MG (n = 60), SCr (n = 60) and serum Cystatin C (n = 39) at following 5 intervals: before operation (T0), 20 minutes before anhepatic phase (T1), 25 minutes in anhepatic (T2), 60 minutes after reperfusion (T3) and at the end of operation (T4). Urinary beta2 MG (n = 60) and NAG (n = 60) were also examined at following 3 intervals: before operation (T0), 60 minutes after reperfusion (T3) and at the end of operation (T4). According to the Rimola A criteria of ARF in 24 hours after operation, all the patients were divided into two groups: ARF group and non-ARF group. The data were statistically analyzed to evaluate the feasibiliy of regarding these factors as prognostic factors for early ARF after liver transplantation in patients with normal SCr and BUN before operation. RESULTS: Ten of sixty cases showed ARF (16.7%). The Logistic regression analysis showed that the levels of serum and urinary beta2 MG as well as serum cystatin C before operation were correlated with early ARF after liver transplantation (P < 0.05), while only serum levels of cystatin C and Cr at the end of operation correlated with early ARF (P < 0.05, P < 0.01) after liver transplantation. The serum beta2 MG, Cystatin C, SCr and urinary beta2 MG levels in ARF group were much more higher than that in non-ARF group (P < 0.05, P < 0.01). There were significant differences between the correct and false predictive positive ratios of serum cystatin C, serum and urinary beta2 MG levels before operation (P < 0.05, P < 0.01), while only SCr showed significant difference between these groups at the end of operation (P < 0.01). CONCLUSIONS: The results revealed that there was potential renal damage among those patients who demonstrated normal SCr and BUN before operation, and that liver transplantation could aggravate this damage and causing ARF. Here we provided the prognostic values of serum Cystatin C, beta2 MG, urinary beta2 MG and NAG in patients with early acute renal failure after liver transplantation.