Adsorption and mechanism study for phenol removal by 10% CO2 activated bio-char after acid or alkali pretreatment.

The development of an efficient bio-char used to remove phenol from wastewater holds great importance for environmental protection. In this work, wheat straw bio-char (BC) was acid-washed by HF and activated at 900 °C with 10% CO2 to obtain bio-char (B-Ⅲ-0.1D900). Adsorption experiments revealed that B-Ⅲ-0.1D900 achieved a remarkable phenol removal efficiency of 90% within 40 min. Despite its relatively low specific surface area of 492.60 m2/g, it exhibited a high maximum adsorption capacity of 471.16 mg/g. Furthermore, B-Ⅲ-0.1D900 demonstrated a good regeneration capacity for at least three cycles (90.71%, 87.54%, 84.36%). It has been discovered that HF washing, which removes AAEM and exposes unsaturated functional groups, constitutes one of the essential prerequisites for enhancing CO2 activation efficiency at high temperatures. After 10% CO2 activation, the mesoporous structure exhibited substantial development, facilitating enhanced phenol infiltration into the pores when compared to untreated BC. The increased branching of the bio-char culminated in a more complete aromatic system, which enhances the π-π forces between the bio-char and the phenol. The presence of tertiary alcohol structure enhances the hydrogen bonding forces, thereby promoting intermolecular multilayer adsorption of phenol. With the combination of various forces, B-Ⅲ-0.1D900 has a good removal capacity for phenol. This work provides valuable insights into the adsorption of organic pollutants using activated bio-char.

Comparison of the clinical efficacy and toxicity of nebulized polymyxin monotherapy and combined intravenous and nebulized polymyxin for the treatment of ventilator-associated pneumonia caused by carbapenem-resistant gram-negative bacteria: a retrospective cohort study.

Objective: To investigate the clinical efficacy and toxicity of nebulized polymyxin monotherapy and combined intravenous and nebulized polymyxin for the treatment of VAP caused by CR-GNB. Additionally, among patients treated with nebulized polymyxin monotherapy, we compared the clinical efficacy and toxicity of polymyxin B and polymyxin E. Methods: This study was a single-center, retrospective study. Included patients received aerosolized polymyxin for at least 72 h with or without intravenous polymyxin for the management of CR-GNB VAP. The primary endpoint was clinical cure at the end of polymyxin therapy. Secondary endpoints included AKI incidence, time of bacteria-negative conversion, duration of MV after inclusion, length of stay in ICU, and all-cause ICU mortality. Results: 39 patients treated with nebulized polymyxin monotherapy were assigned to the NL-polymyxin group. 39 patients treated with nebulized polymyxin combined with intravenous use of polymyxin were assigned to the IV-NL-polymyxin group. Among the NL-polymyxin group, 19 patients were treated with polymyxin B and 20 with polymyxin E. The clinical baseline characteristics before admission to the ICU and before nebulization of polymyxin were similar between the two groups. No differences were found between the two study groups in terms of microorganism distribution, VAP cure rate, time of bacteria-negative conversion, duration of MV after inclusion, length of stay in ICU and all-cause ICU mortality. Similarly, survival analysis did not differ between the two groups (χ2 = 3.539, p = 0.06). AKI incidence was higher in the IV-NL-polymyxin group. When comparing the clinical efficacy and toxicity to polymyxin B and polymyxin E, there was no difference between the two groups in terms of VAP cure rate, time of bacteria-negative conversion, duration of MV after inclusion, length of stay in ICU, SOFA score, CPIS, AKI incidence and all-cause ICU mortality. Conclusion: Our study found that nebulized polymyxin monotherapy was non-inferior to combination therapy with intravenous polymyxin in treating CR-GNB-VAP. Furthermore, we observed no differences in clinical efficacy or related toxic side effects between polymyxin B and polymyxin E during nebulized polymyxin therapy as monotherapy. However, future prospective studies with larger sample sizes are required to confirm these findings.

[Regularity of ventilator-associated pneumonia induced by three common pathogens].

OBJECTIVE: To investigate the incidence and infection regularity of ventilator-associated pneumonia (VAP) in patients undergoing tracheal intubation and to provide reference for the prevention and treatment of VAP infection in the future. METHODS: A retrospective study was conducted to collect the microbial data of airway secretion cultures from 72 patients with endotracheal intubation admitted to the emergency ward of Shanghai Fifth People's Hospital from May 2020 to February 2021, and the species of microorganisms and intubation time were statistically analyzed. RESULTS: Among 72 patients with endotracheal intubation, males were more than females (58.33% vs. 41.67%); Patients over 60 years old accounted for 90.28%; pneumonia was the main primary disease, accounting for 58.33%. Pathogenic tests showed that: (1) 72 patients were infected with Acinetobacter baumannii (AB), Klebsiella pneumoniae (KP), and Pseudomonas aeruginosa (PA) 48 hours after intubation, 51.39% (37/72), 27.78% (20/72), and 26.39% (19/72), respectively. The infection rate of AB was significantly higher than that of KP and PA. Within 48 hours of intubation, the infection rates of AB, KP, and PA were 20.83% (15/72), 13.89% (10/72), and 4.17% (3/72), respectively. Of the 42 patients with primary pneumonia, 61.90% (26/42) were infected with one or more of the three pathogenic bacteria AB, KP, and PA 48 hours after intubation, indicating a change in the etiology of the pathogenic bacteria, with the main pathogenic bacteria transitioning from other pathogenic bacteria to AB, KP, and PA. (2) AB, KP, and PA were prone to cause late onset VAP (i.e., intubation ≥ 5 days). Respectively, among VAP patients infected with AB, late onset VAP accounted for 59.46% (22/37). Among patients infected with KP, 75.00% (15/20) had late onset VAP. Among patients infected with PA, late onset VAP accounted for 94.74% (18/19), indicating a higher proportion of late onset VAP caused by PA and KP. (3) Infection was closely related to intubation time, and the pipeline can be replaced according to the peak period of infection. AB and KP infections peaked within 4 days after intubation, reaching 57.69% (30/52) and 50.00% (15/30), respectively. It is recommended to replace the tubes or undergo sensitive antimicrobial therapy around 3-4 days after starting the machine. The proportion of PA infection after 7 days of intubation was 72.73% (16/22), and it was considered to replace the pipeline after 7 days. (4) Most of the three pathogenic bacteria, AB, KP, and PA were carbapenem resistant pathogens with multiple drug resistance. Except for PA, the infection rate of carbapenem resistant bacteria (CRAB, CRKP) was significantly higher than that of non-carbapenem resistant bacteria (AB, KP), accounting for 86.54% (45/52) and 66.67% (20/30) of the corresponding infection cases, respectively, while CRPA only accounts for 18.18% (4/22). CONCLUSIONS: The main differences in VAP infection caused by AB, KP, and PA pathogens are infection time, infection probability, and carbapenem resistance. Targeted prevention and treatment measures can be implemented for patients with intubation.

Dispersion-optimized optical fiber for high-speed long-haul dense wavelength division multiplexing transmission.

Four non-zero-dispersion-shifted fibers with almost the same large effective area (A(eff)) and optimized dispersion properties are realized by novel index profile designing and modified vapor axial deposition and modified chemical vapor deposition processes. An A(eff) of greater than 71 µm(2) is obtained for the designed fibers. Three of the developed fibers with positive dispersion are improved by reducing the 1550 nm dispersion slope from 0.072 ps/nm(2)/km to 0.063 ps/nm(2)/km or 0.05 ps/nm(2)/km, increasing the 1550 nm dispersion from 4.972 ps/nm/km to 5.679 ps/nm/km or 7.776 ps/nm/km, and shifting the zero-dispersion wavelength from 1500 nm to 1450 nm. One of these fibers is in good agreement with G655D and G.656 fibers simultaneously, and another one with G655E and G.656 fibers; both fibers are beneficial to high-bit long-haul dense wavelength division multiplexing systems over S-, C-, and L-bands. The fourth developed fiber with negative dispersion is also improved by reducing the 1550 nm dispersion slope from 0.12 ps/nm(2)/km to 0.085 ps/nm(2)/km, increasing the 1550 nm dispersion from -4 ps/nm/km to -6.016 ps/nm/km, providing facilities for a submarine transmission system. Experimental measurements indicate that the developed fibers all have excellent optical transmission and good macrobending and splice performances.