Use of cardiac contractility modulation combined with left bundle branch pacing CRT-P in a female with a 22-year history of non-ischemic dilated cardiomyopathy: A case report.

Cardiac contractility modulation (CCM) is a novel device-based therapy used to treat patients with heart failure with reduced ejection fraction (HFrEF). In both randomized clinical trials and real-life studies, CCM has been shown to improve exercise tolerance and quality of life, reverse left ventricular remodeling, and reduce hospitalization in patients with HFrEF. In this case report, we describe for the first time the use of CCM combined with left bundle branch pacing (LBBP) cardiac resynchronization therapy pacemaker (CRT-P) implantation therapy in a female with a 22-year history of non-ischemic dilated cardiomyopathy. With the optimal medical therapy and cardiac resynchronization therapy (CRT) strategies, the patient's quality of life initially recovered to some extent, but began to deteriorate in the past year. Additionally, heart transplantation was not considered due to economic reasons and late stage systolic heart failure. This is the first case of CCM implantation in Fujian Province and the first report of a combined CCM and left bundle branch pacing CRT-P implantation strategy in a patient with non-ischemic etiology dilated cardiomyopathy in China.

The Characteristic of Biofilm Formation in ESBL-Producing K. pneumoniae Isolates.

Klebsiella pneumoniae is a pathogen that commonly causes hospital-acquired infections. Bacterial biofilms are structured bacterial communities that adhere to the surface of objects or biological tissues. In this study, we investigated the genome homology and biofilm formation capacity of ESBL-producing K. pneumoniae. Thirty ESBL-producing K. pneumoniae isolates from 25 inpatients at Ruijin Hospital, Shanghai, were subjected to pulsed-field gel electrophoresis (PFGE) to estimate genomic relatedness. Based on the chromosomal DNA patterns we obtained, we identified 21 PFGE profiles from the 30 isolates, eight of which had high homology indicating that they may have genetic relationships and/or potential clonal advantages within the hospital. Approximately 84% (21/25) of the clinical patients had a history of surgery, urinary tract catheterization, and/or arteriovenous intubation, all of which may have increased the risk for nosocomial infections. Biofilms were observed in 73% (22/30) of the isolates and that strains did not express type 3 fimbriae did not have biofilm formation capacity. Above findings indicated that a high percentage of ESBL-producing K. pneumoniae isolates formed biofilms in vitro and even though two strains with cut-off of PFGE reached 100% similarity, they generated biofilms differently. Besides, the variability in biofilm formation ability may be correlated with the expression of type 3 fimbriae. Thus, we next screened four ESBL-producing K. pneumoniae isolates (Kpn5, Kpn7, Kpn11, and Kpn16) with high homology and significant differences in biofilm formation using PFGE molecular typing, colony morphology, and crystal violet tests. Kpn7 and Kpn16 had stronger biofilm formation abilities compared with Kpn5 and Kpn11. The ability of above four ESBL-producing K. pneumoniae isolates to agglutinate in a mannose-resistant manner or in a mannose-sensitive manner, as well as RNA sequencing-based transcriptome results, showed that type 3 fimbriae play a significant role in biofilm formation. In contrast, type 1 fimbriae were downregulated during biofilm formation. Further research is needed to fully understand the regulatory mechanisms which underlie these processes.

Cobalt Homeostatic Catalysis for Coupling of Enaminones and Oxadiazolones to Quinazolinones.

Transition metal catalysis has revolutionized modern synthetic chemistry for its diverse modes of coordination reactivity. However, this versatility in reactivity is also the predominant cause of catalyst deactivation, a persisting issue that can significantly compromise its synthetic value. Homeostatic catalysis, a catalytic process that can sustain its productive catalytic cycle even when chemically disturbed, is proposed herein as an effective tactic to address the challenge. In particular, a cobalt homeostatic catalysis process has been developed for the water-tolerant coupling of enaminones and oxadiazolones to quinazolinones. Dynamic covalent bonding serves as a mechanistic handle for the preferred buffering of water onto enaminone and reverse exchange by a released secondary amine, thus securing reversible entry into cobalt's dormant and active states for productive catalysis. Through this homeostatic catalysis mode, a broad structural scope has been achieved for quinazolinones, enabling further elaboration into distinct pharmaceutically active agents.

A Cross-Sectional Study of Clostridium Difficile Infection in Inpatients with Antibiotic Associated Diarrhea.

BACKGROUND: Clostridium difficile (C. difficile) is a Gram-positive, anaerobic, spore-forming bacillus that can cause pseudomembranous colitis and other C. difficile-associated diseases, resulting in significant morbidity and mortality. The incidence and clinical features vary by geography. METHODS: In this cross-sectional study, we examined the incidence and clinical features of C. difficile infection (CDI) within a 2,900-bed academic medical center in a southern area of China from January 1, 2017, to December 31, 2020. All adult inpatients (aged ≥ 18 years) who submitted loose stool samples for C. difficile testing over this period were considered for the study. RESULTS: This cross-sectional study showed that the average incidence of CDI was 2.07 cases/100,000 hospital patient-days. The mean age of these inpatients was 71.21 ± 2.83 years (range 30 - 93 years), and 83.61% (51/61) were treated in medical units. We found that 85.25% (52/61) of inpatients with CDI were aged > 60 years. Multivariate logistic regression analysis revealed that age > 60 years, and admission to the geriatric treatment unit or neurosurgery treatment unit were indeed independent risk factors for CDI in inpatients. CONCLUSIONS: The incidence of CDI in the southern area of China was low. Age > 60 years, and treatment in geriatric or neurosurgery units were independent risk factors for CDI inpatients.

Role of rgsA in Oxidative Stress Resistance in Pseudomonas aeruginosa.

Pseudomonas aeruginosa is a common opportunistic pathogen that causes infections in vulnerable patients including those with metabolic disorders, hematologic diseases, and malignancies, and in those who have undergone surgery. In addition, P. aeruginosa exhibits high intrinsic resistance to numerous antibiotics and tends to form biofilms rendering it even more refractory to treatment. Among the mechanisms used by P. aeruginosa to adapt to environmental stresses are those involving small regulatory RNAs (sRNAs), which are 40-500 nucleotides long and are ubiquitous in bacteria. sRNAs play important regulatory roles in various vital processes in diverse bacteria, with their quantity and diversity of regulatory functions exceeding those of proteins. In this study, we show that deletion of the sRNA, rgsA, decreased the growth rate of P. aeruginosa. Furthermore, ΔrgsA P. aeruginosa exhibited decreased ability to resist the stress induced by exposure to different concentrations and durations of peroxides in both planktonic and biofilm growth modes compared with the wild-type strain. These results highlight the role of rgsA in the defense of P. aeruginosa against oxidative stress.

Real-world comparisons of reduced-dose non-vitamin K antagonist oral anticoagulants versus warfarin in atrial fibrillation: a systematic review and meta-analysis.

We performed this meta-analysis to compare the efficacy and safety of reduced-dose non-vitamin K antagonist oral anticoagulants (NOACs) versus warfarin in patients with atrial fibrillation (AF). The PubMed and Embase databases were systematically searched until July 2019 for eligible studies that comparing the effect between any reduced-dose NOAC and warfarin in patients with AF. Risk ratios (RRs) and 95% confidence intervals (CIs) were pooled by using a random-effects model. A total of 14 observational cohorts were included. Compared with warfarin use, the use of reduced-dose NOACs was associated with decreased risks of stroke or systemic embolism (RR, 0.83; 95% CI 0.74-0.93), ischemic stroke (RR, 0.87; 95% CI 0.77-0.98), major bleeding (RR, 0.71; 95% CI 0.60-0.84), intracranial hemorrhage (RR, 0.51; 95% CI 0.44-0.60), and gastrointestinal bleeding (RR, 0.72; 95% CI 0.54-0.94), but not all cause death (RR, 0.84; 95% CI 0.67-1.06). In the subgroup analyses, all NOAC users had lower or similar rates of thromboembolic and bleeding events; and the reductions in stroke or systemic embolism, all-cause death, major bleeding, and gastrointestinal bleeding were more prominent in Asians than non-Asians. In conclusion, current published data suggest that the use of reduced-dose NOACs is non-inferior to warfarin in patients with AF (in particular Asians).

ProGRP AS A NOVEL BIOMARKER FOR THE DIFFERENTIAL DIAGNOSIS OF MEDULLARY THYROID CARCINOMA IN PATIENTS WITH THYROID NODULES.

Objective: To investigate the release of progastrin-releasing peptide (ProGRP) in patients with thyroid nodules and the value of ProGRP in fine-needle aspirate washout fluid (FNA-ProGRP) in the differential diagnosis between medullary thyroid carcinoma (MTC) and non-MTC thyroid nodules. Methods: We investigated 2,446 healthy persons and 212 patients with 235 thyroid nodules. They were classified into healthy, nodular goiter, chronic thyroiditis, thyroid follicular neoplasm, papillary thyroid carcinoma, follicular thyroid carcinoma, and medullary thyroid carcinoma. The serum ProGRP and FNA-ProGRP were measured. Results: The serum ProGRP median concentration in MTC was 124.40 pg/mL, significantly higher than in other groups. The cutoff value of serum ProGRP was 68.30 pg/mL, leading to 53.85% sensitivity, 96.98% specificity, and 0.51 kappa value in MTC. The FNA-ProGRP median concentration in MTC nodules was 2,096.00 pg/mL, significantly higher than in other groups. A receiver operating characteristic analysis of MTC nodules and non-MTC nodules indicated that the cutoff value was 22.77 pg/mL, leading to 94.12% sensitivity, 98.27% specificity, and 0.85 kappa value. Conclusion: FNA-ProGRP measurement could be served as an ancillary method for the differential diagnosis between MTC and non-MTC thyroid nodules. Abbreviations: CEA = carcinoembryonic antigen; CT = calcitonin; FNAC = fine-needle aspiration cytology; FNA-CT = calcitonin in fine-needle aspirate washout fluid; FNA-ProGRP = ProGRP in fine-needle aspirate washout fluid; MTC = medullary thyroid carcinoma; ProGRP = progastrin-releasing peptide; SCLC = small-cell lung cancer; TM = tumor marker.

Expression and clinical value of gastrin-releasing peptide precursor in nephropathy and chronic kidney disease.

AIM: To explore whether serum pro-gastric releasing peptide (proGRP) is elevated in nephropathy patients and evaluate the diagnostic value of proGRP in chronic kidney disease (CKD) patients. METHODS: A total of 498 nephropathy patients and 170 healthy were selected in Zhongshan Hospital, Medical College of Xiamen University, from February 2016 to September 2017. The clinical data of the different groups including serum proGRP, CKD grading, and other serum and urine renal function biomarkers were analyzed by group comparison, correlation analysis and receiver operating characteristic curve. RESULTS: Serum proGRP levels were significantly higher in the acute kidney injury and CKD groups compared with the other groups of kidney disease patients (P < 0.01), and increased with CKD grading (P < 0.01). Serum proGRP was substantially correlated with serum creatinine (r = 0.637, P < 0.01) and cystain C (0.837, P < 0.01). Serum proGRP had moderate correlations with urine ß2-macroglobulin (ß2-m; r = 0.587, P < 0.01) and α1-macroglobulin (α1-m; r = 0.557, P < 0.01). There were fair associations of serum proGRP with albumin (r = 0.10, P = 0.067), 24 h proteinuria (24 h-TPU; r = 0.092, P = 0.099), urinary albumin/urocreatinine (uAlb/Cr; r = 0.29, P < 0.01) and urinary N-acetyl-ß-D-glucosidase (r = -0.142, P < 0.01). The sensitivity of proGRP was superior to that of simplified modification of diet in renal disease (MDRD) formula in diagnosing CKD I + II (81.25% vs 66.67%), CKD III (86.42% vs 74.36%) and CKD IV (71.19% vs 69.64%), while its specificity was inferior to that of simplified MDRD formula in diagnosing CKD I + II (37.65% vs 66.97%), CKD III (56.25% vs 86.67%) and CKD IV (75.31% vs 88.46%). CONCLUSION: Serum proGRP is elevated in acute renal injury and CKD patients and increases with CKD grading. Serum proGRP is mainly affected by glomerular filtration rate and could be used for CKD staging, although the overall diagnostic sufficiency is inferior to simplified MDRD formula.

An Impedance-Loaded Orthogonal Frequency-Coded SAW Sensor for Passive Wireless Sensor Networks.

A passive wireless impedance-loaded orthogonal frequency-coded (OFC) surface acoustic wave (SAW) sensor for wireless sensor networks was proposed in this paper. One of the chips on OFC SAW tag is connected to an external sensor, which could cause a phase shift in the time response of the corresponding part on the SAW device. The phase shift corresponds to the sensed quantity, which could be temperature, strain, vibration, pressure, etc. The OFC SAW tag is isolated by a proper package from the direct effect of the measurand on the device's response which could avoid the multiple measurands coupling. The simultaneous work of multiple sensors is guaranteed by orthogonal frequency coding. By processing the response based on an extended matched filter algorithm, sensing information of the specific coded OFC device can be extracted from the superimposed response of multiple independent encoded sensors. Compared to previous methods, the proposed method can produce a more flexible passive (battery-free) wireless sensor suitable for large-scale wireless sensor networks. Simulation and experimental results demonstrate the effectiveness of the sensor.

Clinical Application of Pro-Gastrin-Releasing Peptide.

BACKGROUND: The diagnostic sensitivity and specificity of serum Pro-gastrin-releasing peptide (ProGRP) in benign or malignant diseases remains controversial. METHODS: The clinical data of 6,948 patients who were examined for ProGRP from February 2015 to January 2017 in the Zhongshan Hospital of the XiaMen University, were collected. The clinical data of the different groups were analyzed by statistical methods. RESULTS: The ProGRP reference levels were 68.50 pg/mL. The percentages of abnormal ProGRP levels were 23.87%, 26.14%, 22.87%, 84.56%, 16.1%, 15.59% and 43.75% for the pneumonia, cardiovascular disease, cerebral vascular disease, renal failure, small cell lung cancer (SCLC), colorectal cancer, and prostate cancer groups, respectively. The 95th percentile of the serum ProGRP concentration levels in the renal failure group was 364.22 pg/mL. The ProGRP cutoff levels for SCLC group were 162.90 pg/mL and the area under the receiver-operating characteristic curve (AUC) was 0.940 (95% CI, 0.892 to 0.987). The parameters sensitivity, specificity, PLR (positive likelihood ratio), NLR (negative likelihood) and Kappa value for the SCLC group with the exclusion of the renal failure group were 81.10% (95% CI: 38.19% - 89.71%), 99.51% (95% CI: 99.31% - 99.66%), 167.59 (95% CI: 116.06 - 241.99), 0.19 (95% CI: 0.11 - 0.32), and 0.6830 (Sig: 0.000), respectively. In the SCLC group, significantly higher concentrations of serum ProGRP of M1 were observed compared with M0. All esophageal neoplasms with high-level ProGRP were identified as small cell neoplasms. CONCLUSIONS: The ProGRP levels were increased in a variety of benign and malignant diseases and were considered a putative marker for SCLC with the exception of the renal failure group. It may be suggested that the high ProGRP levels originated from patients with neuroendocrine tumor.

Hemolysis Combined with Renal Injury after Mitral Valve Repair.

Hemolysis combined with renal injury is a rare but serious complication after mitral valve repair. Here, we report two representative cases of hemolysis combined with renal injury. Although timely reoperation was not possible for several reasons, different clinical outcomes were observed that could aid in future decisions.

Potent Inhibition of miR-34b on Migration and Invasion in Metastatic Prostate Cancer Cells by Regulating the TGF-ß Pathway.

The importance of miRNAs in the progression of prostate cancer (PCa) has further been supported by the finding that miRNAs have been identified as potential oncogenes or tumor suppressors in PCa. Indeed, in eukaryotes, miRNAs have been found to regulate and control gene expression by degrading mRNA at the post-transcriptional level. In this study, we investigated the expression of miR-34 family members, miR-34b and miR-34c, in different PCa cell lines, and discussed the molecular mechanism of miR-34b in the invasion and migration of PCa cells in vitro. The difference analyses of the transcriptome between the DU145 and PC3 cell lines demonstrated that both miR-34b and -34c target critical pathways that are involved in metabolism, such as proliferation, and migration, and invasion. The molecular expression of miR-34b/c were lower in PC3 cells. Moreover, over-expression of miR-34b/c in PC3 cells caused profound phenotypic changes, including decreased cell proliferation, migration and invasion. Moreover, the players that regulate expression levels of transforming growth factor-ß (TGF-ß), TGF-ß receptor 1 (TGF-ßR1), and p53 or phosphorylation levels of mothers against decapentaplegic 3 (SMAD3) in the TGF-ß/Smad3 signaling pathway have yet to be elucidated, and will provide novel tools for diagnosis and treatment of metastatic PCa.

Type D personality is associated with delaying patients to medical assessment and poor quality of life among rectal cancer survivors.

OBJECTIVE: The aim of this research was to explore quality of life (QoL), mental health status, type D personality, symptom duration, and emergency admissions of Chinese rectal cancer patients as well as the relationship between these factors. METHODS: Type D personality was measured with the 14-item Type D Personality Scale (DS14). Mental health status was measured with the Hospital Anxiety and Depression Scale (HADS). The QoL outcomes were assessed longitudinally using the European Organization for Research and Treatment of Cancer QLQ-C30 and QLQ-CR38 questionnaires at the baseline and 6 months after diagnosis. RESULTS: Of the 852 survivors who responded (94 %), 187 (22 %) had a type D personality. The proportion of patients with duration of symptoms >1 month and being diagnosed after emergency admissions in type D group is significantly higher than that in non-type D group. At both of the time points, type D patients reported statistically significant lower scores on most of the functional scales, global health status/QoL scales, and worse symptom scores compared to patients without a type D personality. At the 6-month time point, a higher percentage of patients in the type D group demonstrated QoL deterioration. Clinically elevated levels of anxiety and depression were more prevalent in type D than in non-type D survivors. CONCLUSIONS: Type D personality was associated with poor QoL and mental health status among survivors of rectal cancer, even after adjustment for confounding background variables. Type D personality might be a general vulnerability factor to screen for subgroups at risk for longer symptom duration and emergency admissions in clinical practice.

Autophagy protects human brain microvascular endothelial cells against methylglyoxal-induced injuries, reproducible in a cerebral ischemic model in diabetic rats.

Cerebral microvascular endothelial cells (ECs) are crucial for brain vascular repair and maintenance, but their physiological function may be impaired during ischemic stroke and diabetes. Methylglyoxal (MGO), a reactive dicarbonyl produced during glucose metabolism, could exacerbate ischemia-induced EC injury and dysfunction. We investigated the protective effect of autophagy on cultured human brain microvascular endothelial cells (HBMEC) that underwent MGO treatment. A further study was conducted to explore the underlying mechanisms of the protective effect. Autophagic activity was assessed by evaluating protein levels, using western blot. 3-methyladenine (3-MA), bafilomycin A1, ammonium chloride (AC), Beclin 1 siRNA, and chloroquine (CQ) were used to cause autophagy inhibition. Alarmar blue assay and lactate dehydrogenase release assay were used to evaluate cell viability. Streptozotocin was administered to induce type I diabetes in rats and post-permanent middle cerebral artery occlusion was performed to elicit cerebral ischemia. Blood-brain barrier permeability was also assessed. Our study found that MGO reduced HBMEC cell viability in a concentration- and time-dependent manner, and triggered the responsive autophagy activation. Autophagy inhibitors bafilomycin A1, AC, 3-MA, and BECN1 siRNA exacerbated MGO-induced HBMEC injury. FAK phosphorylation inhibitor PF573228 inhibited MGO-triggered autophagy and enhanced lactate dehydrogenase release. Meanwhile, similar autophagy activation in brain vascular ECs was observed during permanent middle cerebral artery occlusion-induced cerebral ischemia in diabetic rats, while chloroquine-induced autophagy inhibition enhanced blood-brain barrier permeability. Taken together, our study indicates that autophagy triggered by MGO defends HBMEC against injuries.

Relationship between hearing loss and depression: A cross-sectional analysis from the National Health and Nutrition Examination Survey 2015-2018.

BACKGROUND: Hearing loss is a prevalent issue resulting from loud noise exposure, aging, diseases, and genetic differences. As individuals age, the likelihood of experiencing hearing loss and depression escalates; yet, the link between hearing loss and the risk of depression remains ambiguous. This study explores the relationship between hearing and depression risk, taking into account sociodemographic and health-related factors. METHODS: Using data from the National Health and Nutrition Examination Survey (NHANES) 2015-2018, a cross-sectional analysis was conducted, focusing on adult participants. It evaluated their hearing status and depression levels using the Patient Health Questionnaire-9 (PHQ-9). The study examined a range of variables, such as age, gender, socioeconomic status, lifestyle choices, and comorbidities, to understand their influence on the link between hearing loss and depression. RESULTS: Analysis indicated a significant association between moderate to severe hearing loss and an increased risk of depression, notably in older adults. This relationship remained significant even after adjusting for a variety of sociodemographic and health factors. LIMITATIONS: This is a study using the NHANES database using self-reported surveys. CONCLUSION: The findings of this study emphasize the need to integrate hearing health in the holistic assessment and treatment of depression, particularly advocating for combined care strategies for the elderly.

Intranasal administration of recombinant prosaposin attenuates neuronal apoptosis through GPR37/PI3K/Akt/ASK1 pathway in MCAO rats.

Studies have reported that Prosaposin (PSAP) is neuroprotective in cerebrovascular diseases. We hypothesized that PSAP would reduce infarct volume by attenuating neuronal apoptosis and promoting cell survival through G protein-coupled receptor 37(GPR37)/PI3K/Akt/ASK1 pathway in middle cerebral artery occlusion (MCAO) rats. Two hundred and thirty-five male and eighteen female Sprague-Dawley rats were used. Recombinant human PSAP (rPSAP) was administered intranasally 1 h (h) after reperfusion. PSAP small interfering ribonucleic acid (siRNA), GPR37 siRNA, and PI3K specific inhibitor LY294002 were administered intracerebroventricularly 48 h before MCAO. Infarct volume, neurological score, immunofluorescence staining, Western blot, Fluoro-Jade C (FJC) and TUNEL staining were examined. The expression of endogenous PSAP and GPR37 were increased after MCAO. Intranasal administration of rPSAP reduced brain infarction, neuronal apoptosis, and improved both short- and long-term neurological function. Knockdown of endogenous PSAP aggravated neurological deficits. Treatment with exogenous rPSAP increased PI3K expression, Akt and ASK1 phosphorylation, and Bcl-2 expression; phosphorylated-JNK and Bax levels were reduced along with the number of FJC and TUNEL positive neurons. GPR37 siRNA and LY294002 abolished the anti-apoptotic effect of rPSAP at 24 h after MCAO. In conclusion, rPSAP attenuated neuronal apoptosis and improved neurological function through GPR37/PI3K/Akt/ASK1 pathway after MCAO in rats. Therefore, further exploration of PSAP as a potential treatment option in ischemic stroke is warranted.

Palladium-catalyzed coupling of amides and cyclopropanols for the synthesis of γ-diketones.

A palladium catalytic method has been developed for the coupling of amides and cyclopropanols to γ-diketones, through simultaneous C-N and C-C activation. Heteroatom ligand exchange and heteroatom-to-carbon ligation mode switching enable the achievement of molecular cross-coupling in an amide N-atom structural context-dependent manner, avoiding any stoichiometric organometallic reagent or base.

Catalytic Olefin-Imine Metathesis: Cobalt-Enabled Amidine Olefination with Enaminones.

Organic metathesis reactions allow for expedient assembly of diverse molecular skeletons and appendages through the exchange of molecular fragments. The olefin-imine variant of this process, in particular, can expand the synthetic toolbox for manipulating carbon-carbon and carbon-nitrogen bonds but has thus far been achieved only on a stoichiometric metal-mediated basis. Herein, we report the development of a catalytic olefin-imine metathesis reaction, featuring cobalt-catalyzed amidine olefination with enaminones and a versatile product synthon enabling further structural diversification.

Rh(III)-Catalyzed N-Amino-Directed C-H Coupling with 3-Methyleneoxetan-2-ones for 1,2-Dihydroquinoline-3-carboxylic Acid Synthesis.

Dynamic polarity analysis is proposed herein as a general tool for investigating static polarity and transient polarity and revealing expanded reactivity patterns. Through this analysis formalism, polarity matching has been established for Rh(III)-catalyzed N-amino-directed C-H coupling with 3-methyleneoxetan-2-ones, providing efficient access to 1,2-dihydroquinoline-3-carboxylic acids. The identified reaction, by virtue of the internal oxidative mechanism, showcases mild reaction conditions (room temperature), a short reaction time (2 h), and a generally high product yield.

Insights into the proton-enhanced mechanism of hexavalent chromium removal by amine polymers in strong acid wastewater: Reduction of hexavalent chromium and sequestration of trivalent chromium.

Adsorption is a green technology of treating heavy metal-contaminated strong acid wastewaters for the recycling of heavy metal and reuse of strong acid. Herein, three amine polymers (APs) with different alkalinities and electron donating abilities were prepared to investigate the adsorption-reduction processes of Cr(VI). It was found that the removal of Cr(VI) was controlled by the concentration of -NRH+ on the surface of APs at pH > 2, which relies on the alkalinity of APs. However, the high concentration of NRH+ significantly facilitated the adsorption of Cr(VI) on the surface of APs and accelerated the mass transfer between Cr(VI) and APs at strong acid environment (pH ≤ 2). More importantly, the reduction of Cr(VI) was enhanced at pH ≤ 2, due to the high reduction potential of Cr(VI) (E ≥ 0.437). The ratio of reduction to adsorption (α) of Cr(VI) was above 0.70, and the proportion of Cr(III) bonding on Ph-AP excessed 67.6 %. Finally, a proton-enhanced mechanism of Cr(VI) removal was verified by analyzing FTIR and XPS spectra as well as constructing DFT model. This study provides a theoretical basis for the removal of Cr(VI) in the strong acid wastewater.