Identification of early coagulation changes associated with survival outcomes post severe burns from multiple perspectives.

Coagulation alterations manifest early after severe burns and are closely linked to mortality outcomes. Nevertheless, the precise characterization of coagulation changes associated with early mortality remains elusive. We examined alterations in indicators linked to mortality outcomes at both the transcriptomic and clinical characteristic levels. At the transcriptomic level, we pinpointed 28 differentially expressed coagulation-related genes (DECRGs) following burn injuries and endeavored to validate their causal relationships through Mendelian randomization. DECRGs tied to survival exhibit a significant association with neutrophil function, wherein the expression of CYP4F2 and P2RX1 serves as robust predictors of fatal outcomes. In terms of clinical indicators, early levels of D-dimer and alterations in serum calcium show a strong correlation with mortality outcomes. Coagulation depletion and fibrinolytic activation, stemming from the hyperactivation of coagulation pathways post-severe burns, are strongly linked to patient mortality. Monitoring these early coagulation markers with predictive value can effectively identify individuals necessitating priority critical care.

Advances in photodynamic therapy of pathologic scar.

Pathologic scars include keloids and hypertrophic scars due to abnormal wound healing. Both cause symptoms of itching and pain; they also affect one's appearance and may even constrain movement. Such scars place a heavy burden on the individual's physical and mental health; moreover, treatment with surgery alone is highly likely to leave more scarring. Therefore, there is an urgent need for a treatment that is both minimally invasive and convenient. Photodynamic therapy (PDT) is an emerging safe and noninvasive technology wherein photosensitizers and specific light sources are used to treat malignant tumors and skin diseases. Research on PDT from both the laboratory and clinic has been reported. These findings on the treatment of pathologic scars using photosensitizers, light sources, and other mechanisms are reviewed in the present article.

A Bibliometric Analysis of the Trends and Evolution on Inhalation Injury Research.

Inhalation injury is a common complication in burn patients and is also a factor that can affect the multiple prognoses of burn patients. Attention to inhalation injury began early globally, but few articles have systematically analyzed its development. We employed bibliometric methods to analyze articles on inhalation injury published in 3 medical databases. A total of 3056 relevant articles on inhalation injury were included in our analysis and divided into 3 distinct periods based on Price's law. Notably, a slowdown in publication growth was observed in period III. The majority of these articles were authored by a small group of individuals, with a significant proportion of them being American scholars. In fact, nearly half of the articles were published by American researchers. Applying Bradford's Law, we identified 4 major output sources in the field, namely Burns, Journal of Burn Care & Research, Journal of Trauma, and Critical Care Medicine. Recent research has focused on the clinical risks and outcomes associated with inhalation injury, while basic research in this area has been relatively neglected over the last decade. In conclusion, the growth of publications on inhalation injuries has largely followed standard scientific growth patterns, with a small number of countries and established research groups contributing the majority of articles. However, the recent slowdown in scientific output is a cause for concern, and the lack of emphasis on basic research and clinical trials in this field raises questions about the foundation for widespread clinical management of inhalation injuries.

China's strictest water policy: Reversing water use trends and alleviating water stress.

Growing water problems have promoted the Chinese government to implement the strictest water resources management system (SWRMS), the first national policy that puts into practice the concept of "safe operating space" for human water use. Here, we investigate the impact of the SWRMS on China's water use and water stress based on a newly compiled high-resolution and multi-sectoral water use dataset. Results indicate that China's total water use (TWU) increased significantly from 549 km3 yr-1 to 610 km3 yr-1 between 2000 and 2012 (i.e., the pre-SWRMS period), but decreased remarkably in the post-SWRMS period (2012-2020), reaching 565 km3 yr-1 by the year 2020. The decline in TWU was attributed to the improvements of irrigation and industrial water use efficiency (WUE), which were strictly controlled by the SWRMS at various administrative levels of China. The improved WUE has yielded about ∼90 km3 of water savings per year, freeing 17 prefectures from extreme water stress that affects 6% of China's population and 10% of its GDP. Although the improved WUE caused a significant decrease in TWU, the reduction in China's average water stress was insignificant due to the considerable influence of water availability. We further identified hotspots with great potential for water stress reduction, mainly in northwestern China, and hotspots at high risks of water security, primarily on the North China Plain. This study underscores the crucial role of the SWRMS in addressing China's water shortage and provides valuable insights to other countries grappling with water problems in defining their own "safe water operating spaces".

Gut Microbiota and Respiratory Infections: Insights from Mendelian Randomization.

The role of the gut microbiota in modulating the risk of respiratory infections has garnered increasing attention. However, conventional clinical trials have faced challenges in establishing the precise relationship between the two. In this study, we conducted a Mendelian randomization analysis with single nucleotide polymorphisms employed as instrumental variables to assess the causal links between the gut microbiota and respiratory infections. Two categories of bacteria, family Lactobacillaceae and genus Family XIII AD3011, were causally associated with the occurrence of upper respiratory tract infections (URTIs). Four categories of gut microbiota existed that were causally associated with lower respiratory tract infections (LRTIs), with order Bacillales and genus Paraprevotella showing a positive association and genus Alistipes and genus Ruminococcaceae UCG009 showing a negative association. The metabolites and metabolic pathways only played a role in the development of LRTIs, with the metabolite deoxycholine acting negatively and menaquinol 8 biosynthesis acting positively. The identification of specific bacterial populations, metabolites, and pathways may provide new clues for mechanism research concerning therapeutic interventions for respiratory infections. Future research should focus on elucidating the potential mechanisms regulating the gut microbiota and developing effective strategies to reduce the incidence of respiratory infections. These findings have the potential to significantly improve global respiratory health.

[Correlation between blood pressure indexes and prognosis in sepsis patients: a cohort study based on MIMIC-III database].

OBJECTIVE: To investigate the correlation between early-stage blood pressure indexes and prognosis in sepsis patients. METHODS: A retrospective cohort study was conducted on the medical records of patients diagnosed with sepsis from 2001 to 2012 in the Medical Information Mart for Intensive Care-III (MIMIC-III) database. Patients were divided into survival group and death group according to the 28-day prognosis. General data of patients and heart rate (HR) and blood pressure at admission to ICU and within 24 hours after admission were collected. The blood pressure indexes including the maximum, median and mean value of systolic index, diastolic index and mean arterial pressure (MAP) index were calculated. The data were randomly divided into training set and validation set (4 : 1). Univariate Logistic regression analysis was used to screen covariates, and multivariate Logistic stepwise regression models were further developed. Model 1 (including HR, blood pressure, and blood pressure index related variables with P < 0.1 and other variables with P < 0.05) and Model 2 (including HR, blood pressure, and blood pressure index related variables with P < 0.1) were developed respectively. The receiver operator characteristic curve (ROC curve), precision recall curve (PRC) and decision curve analysis (DCA) curve were used to evaluate the quality of the two models, and the influencing factors of the prognosis of sepsis patients were analyzed. Finally, nomogram model was developed according to the better model and effectiveness of it was evaluated. RESULTS: A total of 11 559 sepsis patients were included in the study, with 10 012 patients in the survival group and 1 547 patients in the death group. There were significant differences in age, survival time, Elixhauser comorbidity score and other 46 variables between the two groups (all P < 0.05). Thirty-seven variables were preliminarily screened by univariate Logistic regression analysis. After multivariate Logistic stepwise regression model screening, among the indicators related to HR, blood pressure and blood pressure index, the HR at admission to ICU [odds ratio (OR) = 0.992, 95% confidence interval (95%CI) was 0.988-0.997] and the maximum HR (OR = 1.006, 95%CI was 1.001-1.011), maximum MAP index (OR = 1.620, 95%CI was 1.244-2.126), mean diastolic index (OR = 0.283, 95%CI was 0.091-0.856), median systolic index (OR = 2.149, 95%CI was 0.805-4.461), median diastolic index (OR = 3.986, 95%CI was 1.376-11.758) were selected (all P < 0.1). There were 14 other variables with P < 0.05, including age, Elixhauser comorbidity score, continuous renal replacement therapy (CRRT), use of ventilator, sedation and analgesia, norepinephrine, norepinephrine, highest serum creatinine (SCr), maximum blood urea nitrogen (BUN), highest prothrombin time (PT), highest activated partial thromboplastin time (APTT), lowest platelet count (PLT), highest white blood cell count (WBC), minimum hemoglobin (Hb). The ROC curve showed that the area under the curve (AUC) of Model 1 and Model 2 were 0.769 and 0.637, respectively, indicating that model 1 had higher prediction accuracy. The PRC curve showed that the AUC of Model 1 and Model 2 were 0.381 and 0.240, respectively, indicating that Model 1 had a better effect. The DCA curve showed that when the threshold was 0-0.8 (the probability of death was 0-80%), the net benefit rate of Model 1 was higher than that of Model 2. The calibration curve showed that the prediction effect of the nomogram model developed according to Model 1 was in good agreement with the actual outcome. The Bootstrap verification results showed that the nomogram model was consistent with the above results and had good prediction effects. CONCLUSIONS: The nomogram model constructed has good prediction effects on the 28-day prognosis in sepsis patients, and the blood pressure indexes are important predictors in the model.

Clinical evaluation of high-intensity focused ultrasound ablation combined with mifepristone and levonorgestrel-releasing intrauterine system to treat symptomatic adenomyosis.

OBJECTIVE: To evaluate the clinical efficacy of the combination of high-intensity focused ultrasound (HIFU), mifepristone, and levonorgestrel-releasing intrauterine system (LNG-IUS) in adenomyosis treatment. METHODS: HIFU treatment was performed in 123 patients with symptomatic adenomyosis who had refused treatment with gonadotropin-releasing hormone agonist (GnRH-a) at Anyang Maternal and Child Health Care Hospital. In the control group, 34 patients were treated with HIFU alone, 29 patients with HIFU combined with mifepristone, 10 patients with HIFU combined with LNG-IUS. In the study group, 50 patients were treated with HIFU combined with mifepristone and LNG-IUS. RESULTS: Uterine volume, dysmenorrhea pain score, menstruation volume score, and serum CA125 level were significantly lower after treatment with HIFU combined with mifepristone and LNG-IUS than before treatment (p < .05). Moreover, hemoglobin level was significantly higher than that before treatment (p < .05). After 24 months, the efficacy of HIFU combined with mifepristone and LNG-IUS was significantly higher than that of HIFU alone, HIFU combined with mifepristone or HIFU with LNG-IUS (p < .05). CONCLUSIONS: Combination therapy of HIFU, mifepristone, and LNG-IUS is an effective, safe, and inexpensive treatment for patients with symptomatic adenomyosis. This combination therapy demonstrates superior efficacy to treatment with HIFU alone, HIFU combined with mifepristone, and HIFU combined with LNG-IUS.

Application progress of single-cell sequencing technology in mesenchymal stem cells research.

Single-Cell Sequencing (SCS) technology plays an important role in the field of Mesenchymal Stem Cells (MSCs) research. This paper comprehensively describes the application of SCS technology in the field of MSCs research, including (1) SCS enables more precise MSCs characterization and biomarker definition. (2) SCS reveals the prevalent gene expression heterogeneity among different subclusters within MSCs, which contributes to a more comprehensive understanding of MSCs function and diversity in developmental, regenerative, and pathological contexts. (3) SCS provides insights into the dynamic transcriptional changes experienced by MSCs during differentiation and the complex web of important signaling pathways and regulatory factors controlling key processes within MSCs, including proliferation, differentiation and regulation, and interactions mechanisms. (4) The analytical methods underpinning SCS data are rapidly evolving and converging with the field of histological research to systematically deconstruct the functions and mechanisms of MSCs. This review provides new perspectives for unraveling the biological properties, heterogeneity, differentiation potential, biological functions, and clinical potential of MSCs at the single-cell level.

[Research progress of mesenchymal stem cells and their derivatives nebulization in the treatment of pulmonary diseases].

In acute or chronic lung diseases, inappropriate immune response and abnormal repair process can lead to irreversible damage to lung tissue, which in turn leads to decreased lung function and even respiratory failure or death. Mesenchymal stem cells (MSCs) and their derivatives have shown wide application prospects in cell therapy and acellular therapy of lung diseases and are entering the clinical transformation stage because of their unique physiological functions and characteristics, but the safety and efficacy of MSCs and their derivatives are still controversial. Nebulization therapy provides new opportunities and challenges for the innovative treatment of MSCs and their derivatives in lung diseases. In a number of preclinical studies and clinical trials, there have been evidence that atomization therapy of MSCs and their derivatives is safe and effective. This method could be an optimal solution for the treatment of various complex lung diseases. However, extensive research should be carried out on various strategies and their compatibility with different nebulizers before this method can be used in clinical setting. In this paper, we review the research progress of MSCs and their derivatives by nebulization in the treatment of pulmonary diseases.

Transient Budd-Chiari syndrome secondary to blunt traumatic bile fistula: A case report.

Budd-Chiari syndrome (BCS) is rarely caused by trauma. We reported a case of transient and secondary BCS post polytrauma that resulting from massive perihepatic and abdominal fluid and compressed liver, causing stenosis of the inferior vena cava and hepatic veins. This was a special BCS case related to but not directly caused by trauma. With conservative management and active surgical procedures, the patient recovered well.

Combination of transcriptional biomarkers and clinical parameters for early prediction of sepsis indued acute respiratory distress syndrome.

Objective: As a common yet intractable complication of severe sepsis, acute respiratory distress syndrome (ARDS) is closely associated with poor clinical outcomes and elevated medical expenses. The aim of the current study is to generate a model combining transcriptional biomarkers and clinical parameters to alarm the development of ARDS in septic patients. Methods: Gene expression profile (GSE66890) was downloaded from the Gene Expression Omnibus database and clinical data were extracted. Differentially expressed genes (DEGs) from whole blood leukocytes were identified between patients with sepsis alone and septic patients who develop ARDS. ARDS prediction model was constructed using backward stepwise regression and Akaike Information Criterion (AIC). Meanwhile, a nomogram based on this model was established, with subsequent internal validation. Results: A total of 57 severe septic patients were enrolled in this study, and 28 (49.1%) developed ARDS. Based on the differential expression analysis, six DEGs (BPI, OLFM4, LCN2, CD24, MMP8 and MME) were screened. According to the outcome prediction model, six valuable risk factors (direct lung injury, shock, tumor, BPI, MME and MMP8) were incorporated into a nomogram, which was used to predict the onset of ARDS in septic patients. The calibration curves of the nomogram showed good consistency between the probabilities and observed values. The decision curve analysis also revealed the potential clinical usefulness of the nomogram. The area under the receiver operating characteristic (AUROC) for the prediction of ARDS occurrence in septic patients by the nomogram was 0.86 (95% CI = 0.767-0.952). A sensitivity analysis showed that the AUROC for the prediction of ARDS development in septic patients without direct lung injury was 0.967 (95% CI = 0.896-1.0). Conclusions: The nomogram based on transcriptional biomarkers and clinical parameters showed a good performance for the prediction of ARDS occurrence in septic patients.

Process optimization of polyphenol oxidase immobilization: Isotherm, kinetic, thermodynamic and removal of phenolic compounds.

Chitosan/montmorillonite (CTS/MMT) and chitosan­gold nanoparticles/montmorillonite (CTS-Au/MMT) composites were prepared, characterized through Fourier transformed infrared (FT-IR), X-ray powder diffraction (XRD), and scanning electron microscopy (SEM), and utilized as support for immobilization of polyphenol oxidase (PPO). PPO was immobilized on CTS/MMT (IPPO) and CTS-Au/MMT (IPPO-Au) by physical adsorption, respectively. In order to achieve simultaneous maximization of immobilization efficiency and enzyme activity, the immobilization process parameters were optimized by Taguchi-Grey relational analysis (TGRA) approach. Under the optimal immobilization condition, the immobilization efficiency and enzyme activity reached at 50.16% and 1.46 × 104 U/mg for IPPO, and 63.35% and 3.01 × 104 U/mg for IPPO-Au, respectively. The isotherm, kinetic and thermodynamics of PPO adsorption were investigated in detail. The adsorption process was better explained by Toth isotherm and Fractal-like pseudo second order model, respectively. Intra-particle diffusion and film diffusion were involved in the adsorption process and intra-particle diffusion was not the only rate-controlling step. The adsorption of PPO was exothermic, physical and spontaneous at the investigated temperature range. The immobilized PPO were used to oxidize phenolic compounds. All investigated phenolic compounds showed the higher conversion as catalyzed by IPPO-Au. For both IPPO and IPPO-Au, the conversion of substituted phenols was higher than that of phenol.

Immobilization of polyphenol oxidase on chitosan/organic rectorite composites for phenolic compounds removal.

Chitosan/organic rectorite (CTS/OREC) composites were prepared and characterized by Fourier transform infrared spectrometry and X-ray diffraction. Polyphenol oxidase (PPO) was immobilized on CTS/OREC by physical adsorption (APPO) and covalent binding (CPPO). Taguchi method was applied in the optimization of immobilization conditions resulting in the highest enzyme activity of 16.37 × 103 and 8.92 × 103U/g for APPO and CPPO, respectively. APPO enzyme activity was higher than that of CPPO, while CPPO showed the higher enzyme loading capacity than that of APPO. The removal percentage of phenolic compound, including phenol (PH), 4-chlorophenol (4-CP) and 2,4-dichlorophenol (2,4-DCP), by immobilized PPO was also explored. The results indicated that APPO was more efficient in phenolic compounds removal than CPPO. APPO contributed to a quick removal in the first hour, and the removal percentage of PH, 4-CP and 2,4-DCP could reach 69.3 ± 4.2%, 89.8 ± 2.5% and 93.8 ± 1.7% within 2 h, respectively. The order of removal percentage of phenolic compounds for both immobilized PPO was 2,4-DCP > 4-CP > PH. After 10 consecutive operations, the removal percentage of 2,4-DCP reached 73.2 ± 2.6% and 60.3 ± 1.5% for APPO and CPPO, respectively. The results introduced a novel support for PPO immobilization, and the immobilized PPO had great potential in wastewater treatment.

Immobilized polyphenol oxidase: Preparation, optimization and oxidation of phenolic compounds.

Polyphenol oxidase (PPO) was immobilized on chitosan/montmorillonite (CTS/MMT) and chitosan-gold nanoparticles/montmorillonite (CTS-AuNPs/MMT) composites, respectively. Taguchi method was applied to determine the optimal immobilization conditions for achieving the maximum enzyme activity. PPO immobilized on CTS/MMT (IPPO) and CTS-AuNPs/MMT (IPPO-Au) showed the highest enzyme activity at 15.61 × 103 and 29.01 × 103 U/g, respectively. IPPO-Au exhibited the higher stability and reusability than that of IPPO. The bio-catalytic performance of immobilized PPO was evaluated for the removal of phenol (PH), 4-chlorophenol (4-CP) and 2,4-dichlorophenol (2,4-DCP) in aqueous solution. The effects of pH, temperature, enzyme/substrate ratio, substrate concentration, reaction time on the phenolic compounds removal were investigated in detail. The results showed that, for both immobilized PPO, the optimal pH was 7, 6 and 5 for PH, 4-CP and 2,4-DCP, respectively, and the optimal temperature was 30 °C for all substrate. The optimal enzyme/substrate ratio and reaction time for IPPO-Au was lower than that of IPPO proved the higher catalytic efficiency. Chlorophenols showed the improved catalytic efficiency in comparison with PH for both immobilized PPO, while the effect of substrate chemical structure on the IPPO-Au properties was limited. The results suggested AuNPs presented in support played an important role on the enzyme activity and stability of immobilized PPO.

An in vitro comparison of the antioxidant activities of chitosan and green synthesized gold nanoparticles.

Gold nanoparticles (AuNPs) were synthesized using chitosan with different degree of deacetylation (DD) and molecular weight (MW) as reducing agent and stabilizer. The synthesized AuNPs were characterized by UV-vis spectroscopy, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffractometer (XRD). The OH, ABTS+ and DPPH scavenging activity and ferric reducing antioxidant power (FRAP) of chitosan, synthesized AuNPs and Au colloids were determined through in vitro assays. The antioxidant activity of chitosan decreased with the decreasing of chitosan DD and concentration, while increased with the decreasing of chitosan MW. Low molecular weight chitosan (LMWC, 47.8 kDa) showed the highest antioxidant activity at concentration of 0.3% (w/v). The antioxidant activities of AuNPs were dependent on their size, shape and amount. Spherical AuNPs showed the higher antioxidant activity than irregular or polygonal ones. The antioxidant activities of Au colloids were dependent on the DD, MW and concentration of chitosan. Au colloids synthesized by 0.3% (w/v) LMWC (47.8 kDa) showed the highest antioxidant activity. Compared with chitosan and Au colloids, the improved antioxidant activity of Au colloids may be due to the synergistic effect of AuNPs and chitosan remained in the colloids.

Size controllable one step synthesis of gold nanoparticles using carboxymethyl chitosan.

Gold nanoparticles (AuNPs) were synthesized by reducing chloroauric acid with nontoxic and biodegradable carboxymethyl chitosan (CMC) as dual roles of reducing agent and stabilizer. Several CMC with different molecular parameters, i.e., degree of substitution (DS), substitution position, degree of deacetylation (DD) and molecular weight (MW) have been investigated for their reducing and stabilizing ability on the synthesis of AuNPs. The obtained AuNPs were characterized with UV-vis spectroscopy, transmission electron microscopy and Fourier transform infrared spectroscopy. The resulting AuNPs displayed controllable size and shape not only depending on the molecular parameters of CMC but experimental parameters, such as reaction temperature, time, pH, concentration of NaOH, HAuCl4 and CMC in solution. The results indicated the addition of NaOH to a solution containing HAuCl4 and CMC is essential to synthesize individual spherical AuNPs with a rather uniform size distribution. The -OH at C-6 and -NH2 at C-2 of CMC played important roles in the reduction of Au(III) to Au(0) and -COO- groups were accountable for the stabilizing ability of CMC to AuNPs.

One pot synthesis of gold nanoparticles using chitosan with varying degree of deacetylation and molecular weight.

Gold nanoparticles (AuNPs) were synthesized in one-step by reducing gold salt using nontoxic and biodegradable chitosan as dual roles of reducing agent and stabilizer. The obtained AuNPs were characterized with UV-vis spectroscopy and transmission electron microscopy. The results indicated that control over the size and shape of AuNPs is achieved through the careful selection of experimental conditions, such as reaction temperature, reaction time, concentration of gold salt and chitosan, and chitosan molecular parameters, i.e., degree of deacetylation (DD) and molecular weight (MW). At low chitosan concentration (0.005% and 0.01% (w/v)), individual spherical AuNPs with average particle size around 10nm were obtained regardless of chitosan DD and MW, while anisotropic AuNPs were obtained at concentration above 0.05% (w/v) for all investigated chitosan at the optimum condition (1mL of 1mmol/L HAuCl4 added to 3mL of chitosan solution reacted for 120min at 70°C). The growth of larger polygonal AuNPs was promoted as the higher concentration and lower DD chitosan was used as reducing agent and stabilizer. Au nanoplate was synthesized by water-soluble chitosan (Mv 566kDa, DD 53%) at concentration above 0.15% (w/v). Chitooligomers (Mv 2.4kDa, DD 94%) showed the highest reduction ability for Au3+ and the synthesized AuNPs exhibited aggregation on morphology. It was considered that chitosan DD and concentration played a more important role than MW in the size and shape of AuNPs.

Effect of seawater salinity on pore-size distribution on a poly(styrene)-based HP20 resin and its adsorption of diarrhetic shellfish toxins.

In the present study, okadaic acid (OA) and dinophysistoxin-1 (DTX1) were spiked into artificial seawater at low, medium and high estuarine salinities (9‰, 13.5‰ and 27‰). Passive samplers (HP20 resin) used for solid phase adsorption toxin tracking (SPATT) technology were exposed in these seawaters for 12-h periods. Adsorption curves well fitted a pseudo-secondary kinetics model. The highest initial sorption rates of both toxins occurred in the seawater of medium salinity, followed by seawater of low and high estuarine salinity. Pore volumes of micropores (<2 nm) and small mesopores (2 nm

Modeling total maximum allocated loads for heavy metals in Jinzhou Bay, China.

With the recent development of society and economy in the cities of Huludao and Jinzhou, Liaoning Province, China, environment and ecosystem problems have become increasingly serious in Jinzhou Bay, China, because of the increasing amount of heavy metal pollutants being discharged. To solve these problems, a water quality model of heavy metals coupled with a 3D hydrodynamic model is constructed to estimate the environmental capacity (EC) and total maximum allocated loads (TMALs) for Zn and Cd of three river catchments in Jinzhou Bay. According to the model, the ECs for Zn and Cd are approximately 17 and 8 tons per month, respectively, if the criterion obtained from HC5 values (fifth percentile of the SSD) is set as the control criterion (8.24 µg/L for Zn and 3.83 µg/L for Cd) in Jinzhou Bay, and the TMALs of the three river catchments are 4 and 1.7 tons per month.

Adsorption and flocculation of bentonite by chitosan with varying degree of deacetylation and molecular weight.

Chitosans with different degrees of deacetylation (DD) and molecular weights (Mw) were tested for the flocculation of bentonite suspensions prepared with demineralized water (DW) and tap water (TW), respectively. Flocculation kinetics model of particles collisions combining zeta potential and turbidity measurements was employed to investigate the effects of the DD and Mw of the chitosans on the flocculation properties. The results indicated that the chitosan (Mw 232 kDa) dosages required for maximum flocculation are 20 mg/L in DW and 5 mg/L in TW, respectively, regardless of DD from 54.6% to 95.2% and pH of bentonite suspension. Chitooligomers (Mw 1.5 kDa, DD 95.2%) failed to reach the required residual turbidity (i.e., 10 NTU) in DW under all investigated conditions, whereas good results were obtained using 5-20 mg/L in TW. The polymer-induced flocculation processed obeyed Von Smoluchowski's bimolecular rate equation. The flocculation performance in TW was very different from that in DW due to the presence of salts in TW. The results were consistent with the destabilization of bentonite by the combined mechanisms of charge neutralization and bridging.