Completion rates of bundle treatment of among patients with sepsis shock in intensive care departments of hospitals in Jiangsu Province from 2016 to 2020 years / 中华内科杂志

Current clinical approaches for septic shock increasingly incorporate bundle treatment, a multi-component approach that uses a collection of tests and agents to assist in the identification and treatment of infection. The present study analyzed completion rates of 3 h and 6 h bundle treatment among patients with septic shock in intensive care units (ICUs) of hospitals in Jiangsu Province from 2016 to 2020, using data from the Jiangsu Provincial Intensive Care Medical Quality Control Center. Current approaches and factors affecting treatment completion were assessed.The completion rates of 3 h and 6 h bundle treatment in ICUs of all medical units in Jiangsu Province and in ICUs of hospitals of different levels were recorded. Analyses show that the completion rate of 3 h and 6 h bundle treatment for patients with septic shock in ICUs in Jiangsu Province increased year by year from 2016 to 2020.The completion rate of 3 h bundle treatment increased from 69.82% (3 604/5 162) to 82.47% (8 915/10 775) (all P<0.001). The completion rate of 6 h bundle treatment increased from 62.69% (3 236/5 162) to 72.54% (7 816/10 775) (all P<0.001). In addition, year by year, the completion rate of 3 h bundle treatment in ICUs in tertiary hospitals increased, from 69.80% (3 596/5 152) to 82.23% (7 375/8 969), while the completion rate of 6 h bundle treatment increased from 62.69% (3 230/5 152) to 72.18% (6 474/8 969) (all P<0.001). Completion rates in secondary hospitals also increased year by year, from 80.00% (8/10) to 85.27% (1 540/1 806) for 3 h treatment and from 60.00% (6/10) to 74.31% (1 342/1 806) (all P<0.001) for 6 h treatment. Completion rates for 3 h treatment in first-tier cities (83.99% (2 099/2 499)) and second-tier cities (84.68% (3 952/4 667)) was higher than in third-tier cities (79.36% (2 864/3 609)). The completion rate of 6 h bundle treatment gradually decreased in first-line (77.19% (1 929/2 499)), second-line (74.37% (3 471/4 667)), and third-line (66.94% (2 416/3 609)) cities (all P<0.001). The data collectively show that from 2016 to 2020, the completion rate of bundle treatment in septic shock patients in ICUs in Jiangsu Province improved significantly.

Role of immunodeficiency in Acinetobacter baumannii associated pneumonia in mice / 中华医学杂志(英文版)

BACKGROUND@#Acinetobacter baumannii (A. baumannii) has become one of the most important opportunistic pathogens inducing nosocomial pneumonia and increasing mortality in critically ill patients recently. The interaction between A. baumannii infection and immune response can influence the prognosis of A. baumannii related pneumonia. The target of the present study was to investigate the role of immunodeficiency in A. baumannii induced pneumonia.@*METHODS@#Male BALB/c mice were randomly divided into the normal immunity control (NIC) group, normal immunity infection (NIA) group, immune compromised control (CIC) group, and immune compromised infection (CIA) group (n = 15 for each group). Intraperitoneal injection of cyclophosphamide and intranasal instillation of A. baumannii solution were used to induce compromised immunity and murine pneumonia, respectively. The mice were sacrificed at 6 and 24 h later and the specimens were collected for further tests. Seven-day mortality of mice was also assessed.@*RESULTS@#After A. baumannii stimulation, the recruitment of neutrophils in mice with normal immunity increased sharply (P = 0.030 at 6 h), while there was no significant raise of neutrophil counts in mice with compromised immune condition (P = 0.092 at 6 h, P = 0.772 at 24 h). The Th cell polarization presented with pulmonary interleukin (IL)-4 and interferon (IFN)-γ level in response to the A. baumannii in CIA group were significantly depressed in comparison with in NIA group (IFN-γ: P = 0.003 at 6 h; P = 0.001 at 24 h; IL-4: P < 0.001 at 6 h; P < 0.001 at 24 h). The pulmonary conventional dendritic cell accumulation was even found to be inhibited after A. baumannii infection in immunocompromised mice (P = 0.033). Correspondingly, A. baumannii associated pneumonia in mice with compromised immunity caused more early stage death, more severe histopathological impairment in lung.@*CONCLUSION@#A. baumannii could frustrate the immune response in immunocompromised conditions, and this reduced immune response is related to more severe lung injury and worse outcome in A. baumannii induced pneumonia.

RT-nPCR Assays for Amplification and Sequencing of VP1 Genes in Human Enterovirus A-D from Clinical Specimens / 生物医学与环境科学（英文）

Objective@#To develop RT-nPCR assays for amplifying partial and complete VP1 genes of human enteroviruses (HEVs) from clinical samples and to contribute to etiological surveillance of HEV-related diseases.@*Methods@#A panel of RT-nPCR assays, consisting of published combined primer pairs for VP1 genes of HEV A-C and in-house designed primers for HEV-D, was established in this study. The sensitivity of each RT-nPCR assay was evaluated with serially diluted virus stocks of five serotypes expressed as CCID @*Results@#The sensitivity of RT-nPCR assays for amplifying partial VP1 gene of HEVs was 0.1 CCID @*Conclusion@#This RT-nPCR system is capable of amplifying the partial and complete VP1 gene of HEV A-D, providing rapid, sensitive, and reliable options for molecular typing and molecular epidemiology of HEVs in clinical specimens.

Analysis on spatial epidemiological characteristics of human infection with avian influenza A(H7N9) virus in Fujian Province / 中华疾病控制杂志

Objective The aim is to analyze the spatial epidemiological characteristics for human infection with avian influenza H7N9 in Fujian Province, so as to provide scientific evidence for developing and adjusting related control strategies. Methods The epidemiological data of human infection with H7N9 avian influenza in Fujian Province, from 2013 to 2017 was analyzed by SAS 9.2, ArcGIS 10.3 and SaTScan 9.4 software.Results There were a total of 108 cases and 28 deaths reported in Fujian Province, up to December 31, 2017. The case fatality rate was 25.93%.96.30% of cases were sporadic. There were more incidences in winters and springs, more incidences in rural areas. The global spatial autocorrelation and high/low clustering analysis indicated that clusters at the county level were in the shore areas (Z=3.74, P<0.001; Z=5.26, P<0.001). The cities of Changle, Fuqing, Jinjiang and Siming were the high-high clustered areas and local hot-points. There were two clusters, from December 2014 to March 2015, the most likely cluster regions was centered around Zhangpu County with a radius of 63.04 km (RR=4.72, LLR=11.41, P<0.001). The secondary cluster regions was centered around Fuqing City with a radius of 81.98 km (RR=4.07, LLR=7.96, P=0.037). Conclusions Human infection with avian influenza H7N9 in Fujian Province is spatially and temporally clustered. The measures of prevention and control should be focused on high incidence seasons and key regions, and the surveillance of etiology should be strengthened.

Effect of early intensive blood pressure reduction on outcome in patients with cerebral hemorrhage, a Meta-analysis / 临床神经病学杂志

Objective To determine the effect of early intensive blood pressure reduction on outcome in patients with cerebral hemorrhage.Methods Pubmed,Embase and Web of Science databases were searched to identify relevant randomized controlled trials(RCT)published before Sep 1st 2017.Meta analyzed the effect of early intensive blood pressure control and standard blood pressure control on outcome of patients with cerebral haemorrhage.Results Six RCTs include 4376 patients were included in analysis.The mortality in intensive and standard were 10.8%(235/2177)and 10.8%(238/2199), respectively; while the incidence of major disability was 38.1%(801/2103)and 39.9%(848/2123), respectively.Compare with standard blood pressure control, intensive blood pressure reduction did not reduce the mortality(RR=1.00,95%CI:0.84 -1.18,P=0.98;I2=0%)and the major disability incidence(RR=0.95,95%CI:0.88 -1.03,P=0.23;I2=0%)in patients with cerebral hemorrhage.Conclusion Early intensive blood pressure reduction can not significantly improve the outcome of cerebral hemorrhage patients.

Acute Respiratory Distress Syndrome: Challenge for Diagnosis and Therapy / 中华医学杂志(英文版)

<p><b>Objective</b>Acute respiratory distress syndrome (ARDS) is a devastating clinical syndrome whose diagnosis and therapy are still in question. The aim of this review was to discuss the current challenge for the diagnosis and treatment of ARDS.</p><p><b>Data Sources</b>Data sources were the published articles in English through December 2017 in PubMed using the following key words: "acute respiratory distress syndrome," "definition", "diagnosis," "therapy," "lung protective strategy," "right ventricular dysfunction," and "molecular mechanism."</p><p><b>Study Selection</b>The selection of studies focused on both preclinical studies and clinical studies of therapy of ARDS.</p><p><b>Results</b>The incidence of ARDS is still high, and ARDS causes high intensive care units admissions and high mortality. The Berlin Definition proposed in 2012 is still controversial owing to lack of sensitivity and specificity. ARDS is still under recognition and it is associated with high mortality. Lung protective strategies with low tidal volume (VT) and lung recruitment should consider the physiology of ARDS because ARDS presents lung inhomogeneity; the same low VT might increase local stress and strain in some patients with low compliance, and lung recruitment could injure lungs in ARDS patients with low recruitability and hemodynamic instability. Acute cor pulmonale is common in severe ARDS. ARDS itself and some treatments could worsen acute cor pulmonale. Molecular understanding of the pathogenic contributors to ARDS has improved, but the molecular-associated treatments are still under development.</p><p><b>Conclusions</b>ARDS is a devastating clinical syndrome whose incidence and mortality has remained high over the past 50 years. Its definition and treatments are still confronted with challenges, and early recognition and intervention are crucial for improving the outcomes of ARDS. More clinical studies are needed to improve early diagnosis and appropriate therapy.</p>

Effects of Propofol on Respiratory Drive and Patient-ventilator Synchrony during Pressure Support Ventilation in Postoperative Patients: A Prospective Study / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Propofol is increasingly used during partial support mechanical ventilation such as pressure support ventilation (PSV) in postoperative patients. However, breathing pattern, respiratory drive, and patient-ventilator synchrony are affected by the sedative used and the sedation depth. The present study aimed to evaluate the physiologic effects of varying depths of propofol sedation on respiratory drive and patient-ventilator synchrony during PSV in postoperative patients.</p><p><b>METHODS</b>Eight postoperative patients receiving PSV for <24 h were enrolled. Propofol was administered to achieve and maintain a Ramsay score of 4, and the inspiratory pressure support was titrated to obtain a tidal volume (VT) of 6-8 ml/kg. Then, the propofol dose was reduced to achieve and maintain a Ramsay score of 3 and then 2. At each Ramsay level, the patient underwent 30-min trials of PSV. We measured the electrical activity of the diaphragm, flow, airway pressure, neuro-ventilatory efficiency (NVE), and patient-ventilator synchrony.</p><p><b>RESULTS</b>Increasing the depth of sedation reduced the peak and mean electrical activity of the diaphragm, which suggested a decrease in respiratory drive, while VT remained unchanged. The NVE increased with an increase in the depth of sedation. Minute ventilation and inspiratory duty cycle decreased with an increase in the depth of sedation, but this only achieved statistical significance between Ramsay 2 and both Ramsay 4 and 3 (P < 0.05). The ineffective triggering index increased with increasing sedation depth (9.5 ± 4.0%, 6.7 ± 2.0%, and 4.2 ± 2.1% for Ramsay 4, 3, and 2, respectively) and achieved statistical significance between each pair of depth of sedation (P < 0.05). The depth of sedation did not affect gas exchange.</p><p><b>CONCLUSIONS</b>Propofol inhibits respiratory drive and deteriorates patient-ventilator synchrony to the extent that varies with the depth of sedation. Propofol has less effect on breathing pattern and has no effect on VT and gas exchange in postoperative patients with PSV.</p>

Epidemiological Study of Sepsis in China: Protocol of a Cross-sectional Survey / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Sepsis is the leading cause of death among critically ill patients. Herein, we conducted a national survey to provide data on epidemiology and treatment of sepsis in the clinical practice in China, which has no detailed epidemiological data available on sepsis.</p><p><b>METHODS</b>This was a prospective cross-sectional survey from December 1, 2015 to January 31, 2016 in all provinces/municipalities of the mainland of China. The primary outcome of this study was the incidence of sepsis, and the secondary outcome was its etiology in China. Patients with sepsis admitted to the Intensive Care Units were included in this study. The demographic, physiological, bacteriological, and therapeutic data of these patients were recorded. The incidence of sepsis was estimated using the data from the sixth census in China, reported by the Chinese National Health and Family Planning Commission and the National Bureau of Statistics as the standard population. The independent risk factors for increased mortality from sepsis were calculated.</p><p><b>CONCLUSIONS</b>This study indicated the incidence and outcome of sepsis in China. It also showed the most common etiology of different sites and types of infection, which could guide empiric antibiotic therapy. Moreover, it provided information on the independent risk factors for increased mortality due to sepsis. The findings provide evidence to guide clinical management and may help improve the outcome in septic patients.</p><p><b>TRIAL REGISTRATION</b>ClinicalTrials.gov, NCT02448472; https://clinicaltrials.gov/show/NCT02448472.</p>

Hepatic Perfusion Alterations in Septic Shock Patients: Impact of Early Goal-directed Therapy / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Early goal-directed therapy (EGDT) has become an important therapeutic management in early salvage stage of septic shock. However, splenic organs possibly remained hypoperfused and hypoxic despite fluid resuscitation. This study aimed to evaluate the effect of EGDT on hepatic perfusion in septic shock patients.</p><p><b>METHODS</b>A prospective observational study was carried out in early septic shock patients who were admitted to Intensive Care Unit within 24 h after onset and who met all four elements of the EGDT criteria after treatment with the standard EGDT procedure within 6 h between December 1, 2012 and November 30, 2013. The hemodynamic data were recorded, and oxygen metabolism and hepatic functions were monitored. An indocyanine green clearance test was applied to detect the hepatic perfusion. The patients' characteristics were compared before treatment (T0), immediately after EGDT (T1), and 24 h after EGDT (T2). This study is registered at ClinicalTrials.org, NCT02060773.</p><p><b>RESULTS</b>Twenty-one patients were included in the study; however, the hepatic perfusion data were not included in the analysis for two patients; therefore, 19 patients were eligible for the study. Hemodynamics data, as monitored by pulse-indicator continuous cardiac output, were obtained from 16 patients. There were no significant differences in indocyanine green plasma disappearance rate (ICG-PDR) and 15-min retention rate (R15) at T0 (11.9 ± 5.0%/min and 20.0 ± 13.2%), T1 (11.4 ± 5.1%/min and 23.6 ± 14.9%), and T2 (11.0 ± 4.5%/min and 23.7 ± 15.3%) (all P > 0.05). Both of the alterations of ICG-PDR and R15 showed no differences at T0, T1, and T2 in the patients of different subgroups that achieved different resuscitation goal numbers when elected (P > 0.05).</p><p><b>CONCLUSION</b>There were no hepatic perfusion improvements after EGDT in the early phase of patients with septic shock.</p><p><b>TRIAL REGISTRATION</b>Clinicaltrials.gov NCT02060773 (https://clinicaltrials.gov/ct2/show/NCT02060773).</p>

Fingerprint of X-ray diffraction of Tibetan medicine dairy Nanhanshuishi and its application in processing by microwave / 中国中药杂志

The characteristic fingerprint of conventional dairy Nanhanshuishi was established by X-ray diffraction (XRD), based on similarity of caculation on public peaks by MATLAB software, and the feasibility of new dairy technology of microwave method was explored between XRD and the dissolution rate in artificial simulation gastric juices. The result showed that similarity of shared peak in XRD of conventional dairy Nanhanshuishi was > 95%, This XRD characteristic fingerprint of conventional dairy Nanhanshuishi had strong specificity, could be used to provide a reference for identification and quality evaluation. This study also showed that the similarity of microware dairy products and conventional dairy products was good, and the sample of microwave 15 min was the best, and new dairy method by the microwave could replace the traditional method.

Molecular epidemiology of HFMD-associated pathogen coxsackievirus A6 in Fujian Province, 2011-2013 / 病毒学报

In order to characterize the molecular epidemiology of HFMD-associated Coxsackievirus A6 (CVA6) in Fujian Province, a total of 1340 specimens from non-EV71 non-CVA16 HFMD patients were collected during 2011-2013. Isolated virus strains were identified and subtyped. Full-length coding regions for the VP1 gene of the predominant serotype CVA6 isolates were amplified and sequenced. Among the 375 non-EV71 non-CVA16 HFMD cases confirmed by virus isolation and molecular subtyping, 182 (48.5%) were found to be caused by CVA6, accounting for 7.9%, 16.2% and 39.6% HFMD-associated enteroviruses in FujianProvince during 2011, 2012, and 2013, respectively. Compared with general features observed in the HFMD epidemic, no difference in CVA6-specificity or severity rates was observed between geographical origins, gender, or age groups. Nucleotide sequence analyses of VP1 genes revealed high diversity levels of 16.2%-18.6% among CVA6 strains from Fujian Province, in contrast to the prototype CVA6 strain, and showed low levels of diversity in the amino acid sequences (4.3%-6.2%). Phylogenetic analysis also indicated that CVA6 isolates from Fujian Province were distinct from the prototype strain and other isolates from abroad; however, it was homologous to domestic strains, although the Fujian isolates clustered into multiple branches. These results suggested that significant changes in the pathogenic spectrum of HFMD in Fujian Province occurred during 2011-2013, as CVA6 was one of the predominant serotypes of HFMD. CVA6 isolates from Fujian Province were co-circulating and co-evolving with other domestic strains as multiple closely related CVA6 transmission chains were observed in Fujian Province overall and within each prefecture.

Characteristics of complete genome of pandemic A/H1N1/2009 influenza virus isolated in Fujian Province, China / 病毒学报

This study aims to investigate the characteristics of genomic variation of pandemic A/H1N1/2009 influenza virus isolated in Fujian Province, China. Complete genome sequence analysis was performed on 14 strains of pandemic A/H1N1/2009 influenza virus isolated from Fujian during 2009-2012. All virus strains were typical low-pathogenic influenza viruses, with resistance to amantadine and sensitivity to neuraminidase inhibitors. Eight genome fragments of all strains were closely related to those of A/California/07/2009 (H1N1) vaccine strain, with > or = 98.2% homology. Compared with the vaccine strain, the influenza strains from Fujian had relatively large variation, and variation was identified at 11 amino acid sites of the HA gene of A/Fujiangulou/SWL1155/2012 strain, including 4 sites (H138R, L161I, S185T, and S203T) involved inthree antigen determinants (Ca, Sa, and Sb). In conclusion, the influenza vaccine has a satisfactory protective effect on Fujian population, but the influenza strains from Fujian in 2012 has antigenic drift compared with the vaccine strain, more attention should therefore be paid to the surveillance of mutations of pandemic A/H1N1/2009 influenza virus.

Sequencing and analysis of the complete genome sequence of WU polyomavirus in Fuzhou, China / 病毒学报

WU polyomavirus (WUPyV), a new member of the genus Polyomavirus in the family Polyomaviridae, is recently found in patients with respiratory tract infections. In our study, the complete genome of the two WUPyV isolates (FZ18, FZTF) were sequenced and deposited in GenBank (accession nos. FJ890981, FJ890982). The two sequences of the WUPyV isolates in this study varied little from each other. Compared with other complete genome sequences of WUPyV in GenBank (strain B0, S1-S4, CLFF, accession nos. EF444549, EF444550, EF444551, EF444552, EF444553, EU296475 respectively), the sequence length in nucleotides is 5228bp, 1bp shorter than the known sequences. The deleted base pair was at nucleotide position 4536 in the non-coding region of large T antigen (LTAg). The genome of the WUPyV encoded for five proteins. They were three capsid proteins: VP2, VP1, VP3 and LTAg, small T antigen (STAg), respectively. To investigate whether these nucleotide sequences had any unique features, we compared the genome sequence of the 2 WUPyV isolates in Fuzhou, China to those documented in the GenBank database by using PHYLIP software version 3.65 and the neighbor-joining method. The 2 WUPyV strains in our study were clustered together. Strain FZTF was more closed to the reference strain B0 of Australian than strain FZ18.

Passive leg raising predicts volume responsiveness in patients with septic shock / 中华外科杂志

<p><b>OBJECTIVE</b>To evaluate the hemodynamic response to passive leg raising (PLR) indicates fluid responsiveness in patients with septic shock.</p><p><b>METHODS</b>Twenty patients with septic shock, considered for fluid challenge (FC), were enrolled in the study from June 2009 to May 2010. Hemodynamic changes were determined by pulse-contour derived cardiac index at baseline, before and after PLR, return to baseline for 10 min, before and after fluid challenge (250 ml saline for 10 min). An increase of SV after fluid challenge (FC-ΔSV) ≥ 10% were defined responders.</p><p><b>RESULTS</b>Twenty patients with septic shock were included in the study. PLR and fluid challenge were performed 46 instances, among which 15 instances were defined as response group. SV and pulse pressure induced by PLR (PLR-ΔSV and PLR-ΔPP) were increased significantly in response group [(76 ± 19) ml vs. (65 ± 18) ml, (73 ± 20) mmHg vs. (62 ± 20) mmHg (1 mmHg = 0.133 kPa), P < 0.05], while in nonresponse group there were no significant change. PLR-ΔSV and PLR-ΔPP were correlated with FC-ΔSV (r = 0.51, P = 0.001; r = 0.45, P = 0.006), central venous pressure (CVP) were unrelated with FC-ΔSV. Area under curve (AUC) for PLR-ΔSV, PLR-ΔPP and stroke volume variation (SVV) were 0.846, 0.791 and 0.708. PLR-ΔSV ≥ 12.5% predicted fluid responsiveness with sensitivity of 80% and specificity of 93.5%. PLR-ΔPP ≥ 9.5% predicted fluid responsiveness with sensitivity of 73.3% and specificity of 83.9%.</p><p><b>CONCLUSIONS</b>PLR-ΔSV and PLR-ΔPP can predict fluid responsiveness in patients with septic shock. PLR-ΔSV and PLR-ΔPP have a greater ability in predicting volume responsiveness than CVP and SVV.</p>

Prospective research on the prognosis of septic shock based on the change of lactate concentration in arterial blood / 中华外科杂志

<p><b>OBJECTIVE</b>To evaluate the correlation between the lactate in artery blood and lactate clearance rate and prognosis in patients with septic shock in intensive care unit (ICU).</p><p><b>METHODS</b>Prospectively studied 221 consecutive patients with septic shock from December 2005 to December 2007, the diagnosis of septic shock was made based on the criteria of 2001 ACCP/SCCM. For inclusion in the study, we required admission of the patients within 24 h of septic shock diagnosed. The criteria for exclusion from the study were an age of less than 18 years, pregnancy, serious inadequacy of liver and renal, needing blood purification, or acidosis result of biguanides drugs, or do-not-resuscitate. The eligible patients assigned to early goal-directed therapy. The 6-, 24- and 72-hour lactate clearance rate were calculated, the relationship between the level of lactate, lactate clearance rate, the APACHE II score, the number of failed organ and the 28-day mortality were evaluated.</p><p><b>RESULTS</b>One hundred and five patients with septic shock were admitted, 74 male and 31 female, the mean age was 70 +/- 12 years. The 28-day mortality was 54.3%. The average APACHE II score at baseline was 20 +/- 8, the number of failed organs was 3.0 +/- 1.1 and the average concentration of lactate in artery blood at baseline was (3.8 +/- 3.6) mmol/L. Significant differences of the lactate at 0-, 6-, 24- and 72-hour were found between death group and survival group. There were 69 patients whose lactate in artery blood at baseline was > 2 mmol/L, 24 survived. The lactate clearance rate of 6- and 24-hour in survival group were significantly higher than death group (P < 0.01, P < 0.05, respectively), but the lactate clearance rate of 72-hour was not (P > 0.05). By using a multivariate logistic regression analysis, it showed that the lactate clearance rate of 6-hour was the independent predictive factor of survival. The area under the receiver operating characteristic curve (ROC) was 0.564, 0.649, 0.754, 0.784, respectively according to the level of the lactate at 0-, 6-, 24-hour and the 6-hour lactate clearance rate. The cutoff of 6-hour lactate clearance rate was >or= 30.0%, resulting in a sensitivity of 60.0% and a specificity of 77.3%.</p><p><b>CONCLUSIONS</b>Dynamic observation of lactate level is very important for the survival in the patients with septic shock. Patients with elevated lactate and not decreased rapidly have a worse outcome. The 6-hour lactate clearance rate might be the indicator for predicting the prognosis of patients with septic shock.</p>

Preparation and characterization of a polyvinylpyrrolidone water-based magnetic fluid / 南方医科大学学报

<p><b>OBJECTIVE</b>To prepare a stable water-based magnetic fluid.</p><p><b>METHODS</b>A water-based magnetic fluid was prepared by addition of polyvinylpyrrolidone (PVP) as the coating agent for the magnetic particles. After preparation of Fe3O4 by co-precipitation method, PVP was added for its coating, followed by ultrasonic agitation and purification.</p><p><b>RESULTS</b>The magnetic nanoparticles of homogeneously small size and water-based magnetic fluid were obtained, which had good dispersion in water with strong magnetism.</p><p><b>CONCLUSION</b>PVP can be used as a surfactant to stabilize the magnetic fluid.</p>