Investigation on high-volume fly ash pastes modified with micro-size metakaolin subjected to high temperatures

Portland cement(PC) containing high-volume fly ash(HVFA) is usually used to obtain economical and more sustainable merits, but these merits suffer from dramatically low compressive strength especially at early ages. In this work, the possibility of using micro-size metakaolin(MSK) particles to improve the compressive strength of HVFA paste before and after subjecting to high temperatures was studied. To produce HVFA paste, cement was partially substituted with 70% fly ash(FA), by weight. After that, FA was partially substituted with MSK at ratios fluctuating from 5% to 20% with an interval of 5%, by weight. The effect of MSK on the workability of HVFA mixture was measured. After curing, specimens were subjected to different high temperatures fluctuating from 400 to 1000 ℃ with an interval of 200 ℃ for 2 h. The results were analyzed by different techniques named X-ray diffraction(XRD), thermogravimetry(TGA) and scanning electron microscopy(SEM). The results showed that the incorporation of MSK particles into HVFA mixture exhibited a negative effect on the workability and a positive effect on the compressive strength before and after firing.

Effects of high-volume hemofiltration on alveolar- arterial oxygen exchange in patients with refractory septic shock

BACKGROUND：High-volume hemofiltration （HVHF） is technically possible in severe acute pancreatitis （SAP） patients complicated with multiple organ dysfunction syndrome （MODS）. Continuous HVHF is expected to become a beneficial adjunct therapy for SAP complicated with MODS. In this study, we aimed to explore the effects of fluid resuscitation and HVHF on alveolar- arterial oxygen exchange, the Acute Physiology and Chronic Health Evaluation II （APACHE II） score in patients with refractory septic shock. METHODS：A total of 89 refractory septic shock patients, who were admitted to ICU, the Provincial Hospital affiliated to Shandong University from August 2006 to December 2009, were enrolled in this retrospective study. The patients were randomly divided into two groups： fluid resuscitation （group A, n=41）, and fluid resuscitation plus high-volume hemofiltration （group B, n=48）, The levels of O2 content of central venous blood （CcvO2）, arterial oxygen content （CaO2）, alveolar-arterial oxygen pressure difference P（A-a）DO2, ratio of arterial oxygen pressure/alveolar oxygen pressure （PaO2/ PAO2）, respiratory index （RI） and oxygenation index （OI） were determined. The oxygen exchange levels of the two groups were examined based on the arterial blood gas analysis at different times （0, 24, 72 hours and 7 days of treatment） in the two groups. The APACHE II score was calculated before and after 7-day treatment in the two groups. The levels of CcvO2, CaO2 on day 7 in group A were significantly lower than those in group B （CcvO2：0.60±0.24 vs, 0.72±0.28, P〈0.05; CaO2：0.84±0.43 vs. 0.94±0.46, P〈0.05）. The level of oxygen extraction rate （O2ER） in group A on the 7th day was significantly higher than that in group B （ 28.7±2.4 vs. 21.7±3.4, P〈0.01）. The levels of P（A-a）DO2 and RI in group B on the 7th day were significantly lower than those in group A. The levels of PaO2/PAO2 and OI in group B on 7th day were significantly higher than those in group A （P〈0.05 or P〈0.01）. The APACHE II score in the two groups reduced gradually after 7-day treatment, and the APACHE II score on the 7th day in group B was significantly lower than that in group A （8.2±3.8 vs. 17.2±6.8, P〈0.01）. HVHF combined with fluid resuscitation can improve alveolar- arterial-oxygen exchange, decrease the APACHE II score in patients with refractory septic shock, and thus it increases the survival rate of patients.

Accelerated Carbonation Assessment of High-Volume Fly Ash Concrete

The issue of concrete carbonation has gained importance in recent years due to the increase use in supplementary cementing materials (SCMs) in concrete mixtures. While there is general agreement that concrete carbonation progresses at maximum at a relative humidity of about 60%, the rate may differ in the case of cements blended with SCMs, especially with high-volume fly ash replacements. In this study, the effect of high-volume fly ash concrete exposed to low ambient relative humidity (RH) conditions (57%) and accelerated carbonation (4% CO2) is investigated. Twenty-three concrete mixtures were produced varying in cementitious contents (310, 340, 370, and 400 kg/m3), water-to-cementitious materials ratio (0.45 and 0.50), and fly ash content (0%, 15%, 30%, and 50%) using a low and high-calcium fly ash. The specimens were allowed 1 and 7 days of moist curing and monitored for their carbonation rate and depth through phenolphthalein measurements up to 105 days of exposure. The accelerated carbonation test results indicated that increasing the addition of fly ash also led to increasing the depth of carbonation. Mixtures incorporating high-calcium fly ash were also observed to be more resistant against carbonation than low-calcium fly ash due to the higher calcium oxide (CaO) content. However, mixtures incorporating high-volume additions (50%) specimens were fully carbonated regardless of the type of fly ash used. It was evident that the increase in the duration of moist curing from 1 day to 7 days had a positive effect, reducing the carbonation depth for both plain and blended fly ash concrete mixes, however, this effect was minimal in high-volume fly ash mixtures. The results demonstrated that the water-to-cementitious ratio (W/CM) had a more dramatic impact on carbonation resistance than the curing age for mixtures incorporating 30% or less fly ash replacement, whereas those mixtures incorporating 50% showed minor differences regardless of curing age or W/CM. Based on the compressive strength results, carbonation depth appeared to decrease with increase in compressive strength, but this correlation was not significant.

High-Volume Fly Ash Concrete-A Relevant Step to Sustainable Development

HVFA （high-volume fly ash） concrete could be a sustainable way for by-product utilization to conserve natural resources and protect environment. HVFA concrete can play the role of a high-performance material that may be comparable to the conventional Portland cement concrete. The results of the research programme concerning the relationships between the composition of concrete （w/b ratio, fly ash content and type of cement） and their physical and mechanical properties are presented and discussed in the paper. It is found that the introduction of high-volume fly ash into concrete has caused a decrease in compressive strength at the early age of storage. The significant increase in strength was observed between 28 days and 90 days of curing. The high-volume fly ash concretes were characterized with lower water absorbability and sorptivity than control concrete.

Continuous renal replacement therapy with oXiris®in patients with hematologically malignant septic shock:A retrospective study

BACKGROUND The mortality rate from septic shock in patients with hematological malignancies(HMs)remains significantly higher than that in patients without HMs.A longer resuscitation time would definitely be harmful because of the irreversibly immunocompromised status of the patients.Shortening the resuscitation time through continuous renal replacement therapy(CRRT)with oXiris^(■)would be an attractive strategy in managing such patients.AIM To explore the effects of CRRT and oXiris^(■)in shortening the resuscitation time and modifying the host response by reducing inflammation mediator levels.METHODS Forty-five patients with HM were diagnosed with septic shock and underwent CRRT between 2018 and 2022.Patients were divided into two groups based on the hemofilter used for CRRT(oXiris^(■)group,n=26;M150 group,n=19).We compared the number of days of negative and total fluid balance after 7 d of CRRT between the groups.The heart rate,norepinephrine dose,Sequential Organ Failure Assessment(SOFA)score,and blood lactic acid levels at different time points in the two groups were also compared.Blood levels of inflammatory mediators in the 26 patients in the oXiris^(■)group were measured to further infer the possible mechanism.RESULTS The average total fluid balance after 7 d of CRRT in the oXiris^(■)group was significantly lower than that of patients in the M150 hemofilter group.The SOFA scores of patients after CRRT with oXiris^(■)therapy were significantly lower than those before treatment on day 1(d1),d3 and d7 after CRRT;these parameters were also significantly lower than those of the control group on d7.The lac level after oXiris^(■)therapy was significantly lower than that before treatment on d3 and d7 after CRRT.There were no significant differences in the above parameters between the two groups at the other time points.In the oXiris^(■)group,procalcitonin levels decreased on d7,whereas interleukin-6 and tumor necrosis factor levels decreased significantly on d3 and d7 after treatment.CONCLUSION CRRT with oXiris^(■)hemofilter may improve hemodynamics by reducing inflammatory mediators and playing a role in shortening the resuscitation period and decreasing total fluid balance in the resuscitation phases.

Synergistic Use of CO_(2) Pretreatment and Accelerated Carbonation Curing for Maximum Recycling of Steel Slag

Two carbonation approaches are considered for studying the effects on the hardening mechanisms of slurries made of 100 wt%electric arc furnace steel slag (EAF) slag or 80 wt%EAF slag incorporating 20 wt% of Portland cement,which are applied during the hot-stage pretreatment with simulated gas for raw steel slag or the accelerated carbonation curing of slurry.The mechanical strengths,carbonate products,microstructures and CO_(2) uptakes were quantitatively investigated.Results manifest that accelerated carbonation curing increases the compressive strengths of steel slag slurry,from 17.1 MPa (binder of 80 wt% EAF and 20 wt%cement under standard moisture curing) to 36.0 MPa (binder of 80 wt%EAF and 20 wt%cement under accelerated carbonation curing),with a CO_(2) uptake of 52%.In contrast,hot-stage carbonation applied during the pretreatment of steel slag increases the compressive strengths to 43.7 MPa (binder of 80 wt%carbonated EAF and 20 wt%cement under accelerated carbonation curing),with a CO_(2) uptake of 67%.Hotstage carbonation of steel slag is found for particle agglomeration,minerals remodeling and calcite formed,thus causing an activated steel slag with a dense structure and more active components.Accelerated carbonation curing of steel slag slurry paste results in the newly formed amorphous CaCO_(3),calcite crystalline and silica gels that covered the pores of the matrix,facilitating microstructure densification and strength improvement.Adopting the combinative methods of the hot-stage CO_(2) pretreatment and accelerated carbonation curing creates a promising high-volume steel slag-based binder with high strengths and CO_(2) storage.

Unexpected diffuse lung lesions in a patient with pulmonary alveolar proteinosis:A case report

BACKGROUND Pulmonary alveolar proteinosis(PAP)often presents nonspecifically and can be easily confused with:(1)Idiopathic interstitial lung fibrosis;(2)alveolar carcinoma;(3)pulmonary tuberculosis;and(4)other lung diseases such as viral pneumonia,mycoplasma pneumonia,and chlamydial pneumonia.CASE SUMMARY Diagnosis:In this case,a patient was diagnosed with PAP through transbronchial cryobiopsy(TBCB)and quantitative metagenomic next-generation sequencing,which confirmed the impairment of surfactant turnover as the underlying cause of PAP.Interventions:High-volume total lung lavage was performed for this patient.Outcomes:The patient's clinical condition had improved significantly by the 6-month follow-up,with a 92%finger oxygen saturation.A repeat chest computed tomography scan revealed scattered patchy ground-glass shadows in both lungs,which was consistent with alveolar protein deposition but with a lower density than in the radiograph from October 23,2022.CONCLUSION TBCB has unique advantages in diagnosing atypical alveolar protein deposition,particularly for enabling the early detection of PAP.This information can help patients take preventive measures to prevent or halt PAP development by avoiding dusty environments and seeking treatment with total lung lavage and inhaled granulocyte macrophage colony-stimulating factor.

Decomposition Methods for Manufacturing System Scheduling:A Survey

Manufacturing is the application of labor, tools,machines, chemical and biological processing, to an original raw material by changing its physical and geometrical characteristics, in order to make finished products. Since the first industrial revolution, to accommodate the large-scale production,tremendous changes have happened to manufacturing through the innovations of technology, organization, management, transportation and communication. This work first reviews the highvolume low-mix process by focusing on the quantity production,transfer line and single model assembly line. Then, it reviews the high-volume high-mix process. For such a process type,mixed/multi model assembly line is usually adopted. Hence,two main decisions on them, i.e., balancing and, sequencing are reviewed. Thereafter, it discusses the low-volume high-mix process in detail. Then, technology gap and future work is discussed, and at last, conclusions are given.

Influence of high- and low-volume liver surgery in gallbladder carcinoma

AIM: To clarify whether the performance of liver resections (LR) for incidental gallbladder carcinoma (IGBC)’s depends more on the experience of the hospitals in liver surgery than on complying with the guidelines in Germany.

Association between ICU quality and in-hospital mortality of V-V ECMO-supported patients—the ECMO quality improvement action(EQIA)study:a national cohort study in China from 2017 to 2019

This cohort study was performed to explore the influence of intensive care unit(ICU)quality on in-hospital mortality of veno-venous(V-V)extracorporeal membrane oxygenation(ECMO)-supported patients in China.The study involved all V-V ECMO-supported patients in 318 of 1700 tertiary hospitals from 2017 to 2019,using data from the National Clinical Improvement System and China National Critical Care Quality Control Center.ICU quality was assessed by quality control indicators and capacity parameters.Among the 2563 V-V ECMO-supported patients in 318 hospitals,a significant correlation was found between ECMO-related complications and prognosis.The reintubation rate within 48 hours after extubation and the total ICU mortality rate were independent risk factors for higher in-hospital mortality of V-V ECMO-supported patients(cutoff:1.5%and 7.0%;95%confidence interval:1.05–1.48 and 1.04–1.45;odds ratios:1.25 and 1.23;P=0.012 and P=0.015,respectively).Meanwhile,the V-V ECMO center volume was a protective factor(cutoff of≥50 cases within the 3-year study period;95%confidence interval:0.57–0.83,odds ratio:0.69,P=0.0001).The subgroup analysis of 864 patients in 11 high-volume centers further strengthened these findings.Thus,ICU quality may play an important role in improving the prognosis of V-V ECMO-supported patients.

不同血液净化模式治疗多器官功能衰竭犬对单核细胞功能影响的对比研究

目的探讨连续性静-静脉血液透析滤过(continuous veno-venous hemodiafiltration,CVVHDF)和高容量血液滤过(high-volume hemofilteration,HVHF)2种血液净化方法对多器官功能障碍综合征(multiple organ dysfunction syndrome,MODS)犬的疗效差异。方法 18只Beagle犬采用失血性休克+复苏再灌注+内毒素血症建立MODS模型,随机分为CVVHDF组、HVHF组和MODS组,每组6只。CVVHDF组和HVHF组分别给予CVVHDF、HVHF治疗24h,MODS组未给予治疗。分别于术前(T_1)、内毒素注射后0h(T_2)、6h(T_3)、12h(T_4)、24h(T_5)时,采用流式细胞术通过荧光素标记的Annexin-V检测单核细胞早期及晚期凋亡率,采用ELISA法检测培养上清中白细胞介素(interleukin,IL)-1β、IL-4水平,采用流式细胞术检测犬白细胞抗原(dog leukocyte antigen,DLA)-DR表达水平。结果CVVHDF组和HVHF组T_3~T_5时外周血单核细胞早期凋亡率和晚期凋亡率明显低于MODS组(P<0.05),HVHF组T_3时单核细胞早期凋亡率[(9.51±2.08)%]明显低于CVVHDF组[(11.95±1.09)%](P<0.05);CVVHDF组和HVHF组DLA-DR表达水平T_4时[(8.45±5.60)%、(7.43±3.90)%]、T_5时(13.55±2.93)%、(13.43±6.78)%]明显高于MODS组[(1.77±1.01)%、(2.37±0.90)%](P<0.05),CVVHDF组与HVHF组比较差异无统计学意义(P>0.05);CVVHDF组和HVHF组T_3时培养上清中IL-1β水平[(347.50±10.70)、(421.70±11.40)ng/L]高于MODS组[(278.18±11.66)ng/L](P<0.05),IL-4水平T_3~T_5时高于MODS组(P<0.05);HVHF组T_3时培养上清IL-4水平[(139.23±7.26)ng/L]高于CVVHDF组[(126.85±6.86)ng/L](P<0.05)。结论 CVVHDF及HVHF 2种治疗模式均可改善MODS犬单核细胞功能,HVHF模式在降低单核细胞凋亡、改善单核细胞分泌功能方面优于CVVHDF模式。

Seasonal trend of ambient PCDD/Fs in Tianjin City, northern China using active sampling strategy

The spatial concentrations, seasonal trends, profiles and congener pairs of ambient polychlorinated dibenzo-p-dioxins （PCDDs） and polychlorinated dibenzofurans （PCDFs） were investigated within a seasonally active sampling scheme during Jun 2008 and Jan 2009 in Tianjin City, northern China. The PCDD/F concentrations ranged 14.2-172 fg I-TEQ/m3 （average 69.3 fg I-TEQ/m3） in summer and （89.8-1.01） x 103 fg I-TEQ/m3 （average 509 fg I-TEQ/m3） in winter, respectively, except for the E-waste dismantling site where much higher values were observed （1.04 x 103 fg I-TEQ]m3 in summer and 7.123 x 103 fg I-TEQ/m3 in winter）. The results indicated a significantly seasonal trend with higher TEQ values in winter as compared with summer, which could be related to increased emission sources and seasonal variations of the atmospheric boundary layer height. 2,3,4,7,8-PeCDF was the dominant contributor to the total PCDD/F toxic equivalents, and 2,3,7,8-TCDD was detected at almost all the sampling sites in winter. Most of the similarly substituted PCDD/F congener pairs exhibited high correlations, suggesting that they might have similar environmental fate or sources. But different seasonal and spatial distributions of PCDD/F concentrations indicated that the emission sources might be intermittent.