High SCR Research Articles

Does Severity of Donor Acute Kidney Injury Influence Outcomes Following Kidney Transplantation?

The study purpose was to review retrospectively our single-center experience transplanting kidneys from deceased donors (DD) with acute kidney injury (AKI) according to terminal serum creatinine (tSCr) level. AKI kidneys were defined by a doubling of the DD's admission SCr and a tSCr ≥ 2.0mg/dL. From 1/07 to 11/21, we transplanted 236 AKI DD kidneys, including 100 with a tSCr ≥ 3.0mg/dL (high SCr AKI group, mean tSCr 4.2mg/dL), and the remaining 136 from DDs with a tSCr of 2.0-2.99mg/dL (lower SCr AKI group, mean tSCr 2.4mg/dL). These two AKI groups were compared to 996 concurrent control patients receiving DD kidneys with a tSCr < 1.0mg/dL. Mean follow-up was 69 months. Delayed graft function (DGF) rates were 51%versus 46%versus 29% (p < 0.0001), and 5-year patient and death-censored kidney graft survival rates were 96.8%versus 83.5%versus 82.2% (p=0.002) and 86.7%versus 77.8%versus 78.8% (p=0.18) in the high tSCr AKI versus lower tSCr AKI versus control groups, respectively. Despite a higher incidence of DGF, patients receiving kidneys from DDs with tSCr levels ≥3.0mg/dL have acceptable medium-term outcomes compared to either AKI DDs with a lower tSCr or DDs with a tSCr < 1.0mg/dL.

#2334 Elevated serum admission creatinine in acute heart failure hospitalizations: lifting the veil to understand outcome differences

Abstract Background and Aims Organ crosstalk in heart failure and kidney dysfunction is prevalent and is associated to a high event rate. In this setting elevated serum creatinine (sCr) at acute decompensated heart failure (ADHF) admissions is a strong risk factor for poor outcomes. Current accepted cardiorenal syndrome (CRS) classification is based on timing and initial organ dysfunction and fails at capturing its nature and prognosis. We sought to describe patient (P) profile and outcomes in P hospitalized for ADHF with high admission sCr in function of current CRS classification and assess for stratifying predictors. Method We conducted an observational, analytical and cross-sectional study, with prospective and consecutive data acquisition. We included P over 18 years-old, who were admitted to the Intensive Care Telemetry Unit in our Hospital between July, 2011 and Dec, 2023 due to ADHF. P who received a heart transplant during index admission or those on chronic dialysis were excluded. Clinical, epidemiological and biochemical variables were registered. Renal dysfunction was defined under admission sCr &amp;gt;1.4 mg/dl and divided according to Ronco et al classification, as initially cardiac (type 2) or renal (type 4) origin. We constructed multivariate logistic and survival regression models, with selection of relevant predictors by resampling and regularization of a Lasso regression model. Statistical significance was considered with a 5% of alpha error level. Analysis was conducted using R (R Core Team, 2023). Results A total of 1868 consecutive P were included. P population consisted in type 2: 124 and type 4: 258 P, respectively. We found no differences in gender (p = 0.47), while type 4 were older (75 ± 12 vs 71 ± 12; p &amp;lt; 0.01). Ventricular dysfunction was more severe in type 2 (left ventricular ejection fraction 34 ± 17 vs 41 ± 16%; p &amp;lt; 0.001). While ischaemic heart disease was more prevalent in type 4 (32.8 vs 23.5%; p = 0.001), idiopathic cardiomyopathy was more frequent in type 2 (18.8 vs 7.2%; p = 0.001). Clinical phenotypes differed between groups, being clinical hypoperfusion more frequent in type 2 (32.4 vs 12.3%; p &amp;lt; 0.001). Admission sCr was higher in type 4 (1.9 [0.8] vs 1.6 [0.58] mg/dl; p &amp;lt; 0.001), as was 1st day natriuresis (81 vs 67 mEq; p = 0.01). Both groups experienced a similar diuretic resistance rate (21.2 vs 17.1%; p = 0.34), while type 4 received rescue ultrafiltration more frequently (11.3 vs 3.5%; p &amp;lt; 0.01). Type 2 received a higher inotropic support rate (47.1 vs 19.5%; p &amp;lt; 0.01) and had a longer length of stay (9 vs 7 days; p = 0.01). In-hospital (11.8 vs 11.3%; p = 0.99); 6-month and 1-year mortality rates (66.8 vs 72.8% and 55.1 vs 64.6% respectively; p = 0.3). In a similar way, 1-month (94.8 vs 94.7%), 6-month (72 vs 74.7%) and 1-year readmission rates (59.2 vs 60.9%; p = 0.6) were similar in both groups. A multiple logistic regression model (AUCROC 0.82) identified admission sCr (OR 2.6; CI 95% 2.2-3.2; p &amp;lt; 0.001), inotropic need (OR 1.87; CI 95% 1.4-2.6; p &amp;lt; 0.001), anasarca phenotype (OR 1.63; CI 95% 1.06-2.5; p = 0.02), moderate to severe right ventricular dysfunction (OR 1.4; CI 95% 1.03-1.9; p = 0.03) as independent predictors for a descending sCr behavior during hospitalization, while the lower T3 levels were associated with less probability for a descent of sCr (OR 0.21; CI 95% 0.1-0.46; p &amp;lt; 0.001). Conclusion Organ crosstalk in ADHF hospitalizations was associated with a high event rate. One-year mortality and readmission rates were similar in both groups. Renal support therapies were more frequent under lower kidney reserve conditions. Ventricular dysfunction and systemic congestion phenotype are relevant to a better understanding for potential reversibility at the admission time and may promote actions for outcome enhancing.

Identification of a 9-gene signature to enhance biochemical recurrence prediction in primary prostate cancer: A benchmarking study using ten machine learning methods and twelve patient cohorts

Prostate cancer (PCa) is a prevalent malignancy among men worldwide, and biochemical recurrence (BCR) after radical prostatectomy (RP) is a critical turning point commonly used to guide the development of treatment strategies for primary PCa. However, the clinical parameters currently in use are inadequate for precise risk stratification and informing treatment choice. To address this issue, we conducted a study that collected transcriptomic data and clinical information from 1662 primary PCa patients across 12 multicenter cohorts globally. We leveraged 101 algorithm combinations that consisted of 10 machine learning methods to develop and validate a 9-gene signature, named BCR SCR, for predicting the risk of BCR after RP. Our results demonstrated that BCR SCR generally outperformed 102 published prognostic signatures. We further established the clinical significance of these nine genes in PCa progression at the protein level through immunohistochemistry on Tissue Microarray (TMA). Moreover, our data showed that patients with higher BCR SCR tended to have higher rates of BCR and distant metastasis after radical radiotherapy. Through drug target prediction analysis, we identified nine potential therapeutic agents for patients with high BCR SCR. In conclusion, the newly developed BCR SCR has significant translational potential in accurately stratifying the risk of patients who undergo RP, monitoring treatment courses, and developing new therapies for the disease.

Enhancing strategies for the activity and H2O resistance of MnCo-CMS flexible SCR catalysts and hydrophobic modification by modulating the surface energy

Melamine sponge is a flexible organic rubber-plastic foam characterized by its highly porous three-dimensional mesh structure. By optimizing the carbonization process of the melamine sponge, NH3-SCR catalysts with enhanced flexibility were developed. In this study, MnCo-CMS (Carbonized melamine sponge) catalysts were synthesized using the impregnation method. Response surface methodology (RSM) and central composite design (CCD) were employed to investigate the effects of impregnation time, loading, and calcination temperature on the mass reaction rate and N2 selectivity. The results showed that loading had the most significant influence, followed by calcination temperature and impregnation time. Under the optimal preparation conditions of 32.5 wt% loading, the calcination temperature at 420 °C, and the impregnation time for 342 min, the mass reaction rate could reach 11.02 cm3min-1g−1, and the N2 selectivity could achieve 87.4 %. Experimental validation confirmed that various preparation processes resulted in catalysts with high SCR activity (rate constant k > 9.5 cm3min-1g−1 and N2 selectivity > 80 %). The Mn-Co loading should be within the range of 28–36 wt%, the calcination temperature within the range of 380–420 °C, and the impregnation time should be 150 min or more. Materials with low surface energy could result in excellent hydrophobicity. In this study, it was found that melamine sponges could be modified into low surface energy carbon foams by temperature modulation. The change in surface energy was utilized as a modification approach to enhance the water resistance of the NH3-SCR catalyst. Importantly, the optimized process significantly improved the stability and water resistance of the catalysts.

Selection of maize lines for estimating combining ability in topcrossings

Hybrid maize breeding is carried out based on interline hybridization using heterosis in the first generation. Hybridization efficiency can be increased using parental forms with high combining ability in crosses. The purpose of the study was to identify new self-pollinated lines of maize with high general and specific combining ability, to identify the impact on the accuracy of the estimation of related lines included in the study. The current study was carried out at the FSBSI Agricultural Research Center «Donskoy» in 2021 and 2022. The objects of the study were two testers PD 329, KV 399 and 10 self-pollinated lines, including two lines (KV 410 and DS 22/325) related to tester PD 329, twenty topcross maize hybrids. The method for estimating combining ability was complete topcrosses. Estimation of new self-pollinated lines by the topcross method made it possible to identify the lines ‘KV 498’ and ‘DS 498/203-3’ with a consistently high overall combining ability according to the trait ‘grain productivity’. The specific combining ability was characterized by variability depending on the year of study. Only the line ‘KV 401’ had a high SCR in all years of study. The inclusion of lines related to the testers in the set had no effect or only slightly affected the estimates of the TCS of the remaining unrelated lines. The effect on the SCS was not significant, however, the estimation of the SCS would be more accurate if related lines were excluded from the set. There have been identified such new testcross hybrids with large grain productivity as ‘PD 329 × KV 498’ (3.92 t/ha), ‘KV 399 × KV 498’ (4.71 t/ha),‘KV 399 × KV 401’ (4.80 t/ha), ‘KV 399 × DS 498/203-3’ (4.60 t/ha). They were obtained with the participation of new lines characterized by high general or specific combinative ability, which can be recommended to be included in crossbreeding programs to develop highly heterotic maize hybrids.

Low Serum Creatinine as Well as High Serum Creatinine Is Associated with Prognosis of Patients with Cancer in End-of-Life.

The prognosis of end-of-life patients is challenging, and clinicians have attempted to predict survival more accurately. High serum creatinine (sCr) levels are associated with lower survival rates in patients with various cancers; however, low sCr levels are commonly expected in patients with terminal cancer because of muscle wasting and malnutrition. Therefore, we investigated the prevalence of low and high sCr levels and their association with survival duration in patients with terminal cancer in a palliative care unit. We analyzed the medical records of 280 patients admitted to a palliative care unit. Patients were divided into low (<0.5 mg/dL), normal (0.5-1.2 mg/dL), and high (>1.2 mg/dL) sCr groups. Kaplan-Meier survival curves using sCr levels were plotted and compared using the log-rank test. Using stepwise selection, a multivariable Cox proportional hazards model was used to identify the significant prognostic factors. The median survival durations in the high-, low-, and normal-sCr groups were 9.57 days, 22.26 days, and 27.51 days, respectively. Multivariable Cox proportional hazard model identified that males (hazard ratio [HR], 1.81; 95% confidence interval [CI], 1.16-2.85), poor performance status (HR, 3.43; 95% CI, 1.12-10.54), total parenteral nutrition use (HR, 1.84; 95% CI, 1.09-3.1), high sCr (HR, 2.74; 95% CI, 1.52-4.94), and low sCr (HR, 1.22; 95% CI, 1.07-1.43) were significantly associated with a shorter survival time. Low and high serum creatinine levels were significantly associated with poor survival in patients with cancer at the end-of-life stage. Therefore, readily available and simple biomarkers may help plan advanced care in palliative care settings.

V2O5 supported on NbTiOx: A novel NH3-SCR catalyst with high performance induced by V-Nb-Ti interaction

The traditional vanadia-based catalysts frequently employed for selective catalytic reduction of NOx with NH3 (NH3-SCR) have been criticized for their restricted operating temperature window and subpar low-temperature activity. In the present work, a series of NbTiOx solid solutions were used as supports to prepare V/NbxTi1-x (1.0 wt% V2O5) catalysts. The novel 1V/Nb0.15Ti0.85 catalyst presented superior catalytic performance and excellent resistance to SO2 in the SCR reaction, reaching above 95% NOx conversion in a wide temperature range from 270 to 485 °C. In comparison to pure TiO2, Nb-Ti-O solid solution support exhibited different pore structures and pore sizes, contributing to much larger specific surface area. Meanwhile, the surface Nb-OH and Nb = O bonds could serve as new acid sites to facilitate more NH3 adsorption. More importantly, there was a strong redox-acid interaction (V-Nb-Ti) for 1V/Nb0.15Ti0.85 catalyst, which induced the formation of highly redox-active V sites and promoted the activation of adsorbed ammonia, facilitating the NH3-SCR reaction. Unlike 1V/Ti, NOx species adsorbed on 1V/Nb0.15Ti0.85 participated in NH3-SCR reaction below 250 °C, further promoting the low-temperature activity. This study provides a novel vanadium-based catalyst with a low vanadium loading and high SCR activity for practical NOx abatement.

A novel strategy for efficient utilization of manganese tailings: High SO2 resistance SCR catalyst preparation and faujasite zeolite synthesis

Herein, a core-shell structure SiO2@Mn catalyst was successfully synthesized from manganese tailings for NO removal through selective catalytic reduction with ammonia at low temperature. In the presence of 10 % H2O and 100 ppm SO2, the SiO2@Mn catalyst exhibited excellent catalytic activity of 85 % NO conversion at 225 °C. This special core-shell was constructed by inert nano-SiO2 particles, which grew and encapsulated on the surface of manganese oxide, inhibiting the reaction between SO2 with MnOx and thus improving the SO2 resistance. Furthermore, a filter residue was generated in the process of catalysts preparation. Under proper hydrothermal conditions, the residue comprising of Si, Al, and O was used to synthesize high-crystallinity X-type zeolite. This process fully utilized manganese tailings and inspired for Mn-based catalysts design and X-type zeolite preparation, realizing the dual benefits of atmosphere purification and solid waste disposal.

A redox model for NO oxidation, NH3 oxidation and high temperature standard SCR over Cu-SSZ-13

A kinetic model is developed to predict the influence of temperature and hydrothermal aging on the redox of active Cu sites under standard SCR, NO oxidation and NH3 oxidation conditions over a practically relevant fully-formulated Cu-SSZ-13 catalyst. NO2/N2 production during NO/NH3 titration of CuII sites is utilized to identify rate parameters associated with NO-only RHC (reduction half cycle) and NH3-only RHC respectively. Integral N2 formation during subsequent NO + NH3 titration is consistent with the production of one NO2 per two CuII sites reduced during NO-only RHC and one N2 per six CuII sites reduced during NH3-only RHC. Decreased reduction of CuII sites by NO/NH3 upon hydrothermal aging, along with the production of one NO2 per two CuII sites during NO-only RHC, is accordant with the involvement of proximal ZCuOH and oxygen-bridged dimeric CuII sites. Oxidation of partially solvated and framework coordinated ZCu (CuI) sites occurs in presence of O2, does not produce N2 and can lead to the consumption of Brønsted acid sites. A global OHC kinetic model is developed to predict transient and integral N2 formation during exposure of CuI sites to a mixture of NO and O2. The resulting redox kinetic model quantitatively predicts NO and NH3 consumption during isothermal transient response Cu redox (TRCR) protocols, along with temperature and age dependent steady-state standard SCR and oxidation conditions. The redox model presented in this work synthesizes recent kinetic, spectroscopic and computational findings to provide a foundational description of active site redox during standard SCR, NO oxidation and NH3 oxidation over Cu-SSZ-13.

Association between uric acid level and contrast-induced acute kidney injury in patients with type 2 diabetes mellitus after coronary angiography: a retrospective cohort study

BackgroundThis study assessed the predictive value of uric acid (UA) for contrast-induced acute kidney injury (CI-AKI) in patients with type 2 diabetes mellitus (T2DM) who underwent coronary angiography (CAG). A nomogram to aid in the prediction of CI-AKI was also developed and validated, and the construction of a prognostic nomogram combined with clinical features was attempted.MethodsThis study retrospectively enrolled T2DM patients who underwent CAG between December 2019 and December 2020 at the Affiliated Zhongda Hospital of Southeast University. Multivariable logistic regression analysis was used for the analysis of clinical outcomes. Receiver operating characteristic (ROC) analyses were performed to determine the area under the ROC curve (AUC) and the cut-off points for continuous clinical data. The prediction accuracies of models for CI-AKI were estimated through Harrell’s concordance indices (C-index). Nomograms of the prognostic models were plotted for individualized evaluations of CI-AKI in T2DM patients after CAG.ResultsA total of 542 patients with T2DM who underwent CAG were included in this study. We found that a high UA level (≥ 425.5 µmol/L; OR = 6.303), BUN level (≥ 5.98 mmol/L; OR = 3.633), Scr level (≥ 88.5 µmol/L; OR = 2.926) and HbA1C level (≥ 7.05%; OR = 5.509) were independent factors for CI-AKI in T2DM patients after CAG. The nomogram model based on UA, BUN, Scr and HbA1C levels presented outstanding performance for CI-AKI prediction (C-index: 0.878). Decision curve analysis (DCA) showed good clinical applicability in predicting the incidence of CI-AKI in T2DM patients who underwent CAG.ConclusionHigh UA levels are associated with an increased incidence of CI-AKI in T2DM patients after CAG. The developed nomogram model has potential predictive value for CI-AKI and might serve as an economic and efficient prognostic tool in clinical practice.

Study on the role of Fe species and acid sites in NH3-SCR over the Fe-based zeolites

Fe doped ZSM-5 zeolite catalysts, prepared with solution ion-exchange method, calcinated at various temperatures and aged with/without H2O, were tested for activity in the selective catalytic reduction of NOx with NH3 (NH3-SCR) and characterized by XRD, NMR, UV‐Vis, XPS, H2-TPR, NH3-TPD and in-situ DRIFTs for structure and species change to investigate the role of Fe sites and acidity in SCR reaction. The results showed that the SCR activity for the Fe-ZSM-5 was mainly dependent on the active Fe species rather than acidity. Fe-oxo related Lewis sites were important for the low temperature SCR reaction, while high Brønsted acidity was not necessary for a high SCR activity. It should be noticed that the inactive free Fe2+ ions could be converted to isolated Fe3+ species by high temperature during calcination and aging, which could be inhibited by H2O due to dealumination during hydrothermal aging. This resulted in the decreased SCR activity after aging in the presence of H2O and the improved NO conversion after high-temperature calcination and thermal aging due to that the isolated Fe3+ acted as the main active site at temperature <500 ℃. The in-situ DRIFTs study showed that NH3 adsorption on acid sites was not the necessary step for the low-temperature SCR reaction but essential to NH3 oxidation, and the Eley-Rideal (E-R) mechanism was the main pathway for standard NH3-SCR.

Effect of morphology and simultaneous sulfation on Fe doped CeO2 for selective catalytic reduction of NOx with NH3

Researchers have been developing novel environment-friendly NH3-SCR catalysts for controlling NOx emission from fossil fuel combustion. Fe doped CeO2 catalysts with nanorod, nanocube and nanopolyhedron shape were synthesized and sulfation was conducted on porous nanorod simultaneously. Their NOx conversions were in sequence of sulfated porous nanorod (S-FeCeOx) > nanorod (R-FeCeOx) > nanopolyhedron (P-FeCeOx) > nanocube (C-FeCeOx) and presented distinct morphology dependence. S-FeCeOx catalyst possessed above 95 % NOx conversion and nearly 100 % N2 selectivity in very high gas hourly space velocity of 240, 000 mL·g−1·h−1 at 275–400 °C. The sequence of BET specific surface area was: P-FeCeOx > R-FeCeOx > S-FeCeOx > C-FeCeOx and thus the change of physical adsorption capacity may be not the main reason for high SCR catalytic activity of S-FeCeOx and R-FeCeOx. Fe doping and sulfation induced porous nanorod shape with preferentially exposed {110} faces, most oxygen vacancy defect sites and highest surface chemisorbed oxygen ratio, which contributed to the highest NOx conversion of S-FeCeOx. Fe doping mainly increased strong acid sites, and surface sulfate species significantly increased Brønsted acid sites promoting NH3 adsorption and suppressed NOx adsorption on S-FeCeOx catalyst, beneficial to both high NOx conversion and low N2O formation on it. R-FeCeOx catalyst mainly followed Langmuir-Hinshelwood mechanism, while SCR reaction mechanism was changed by sulfation and S-FeCeOx catalyst mainly followed Eley-Rideal mechanism.

In situ synthesis of low-valence MnO/Mn3O4 catalyst via carbon-acid hydrothermal strategy for NO removal

A rational design of high dispersion MnO/Mn 3 O 4 catalysts based on carbon-acid hydrothermal strategy was proposed for selective catalytic reduction of NO at low temperature. The ultra-high denitration rate can be attributed to the abundant Lewis acid sites and reactive oxygen species, and the reaction followed Langmuir-Hinshelwood reaction route. • High dispersed MnO/Mn 3 O 4 catalyst was prepared by carbon-acid hydrothermal method. • Catalyst achieved exceeding 98 % NO removal in the temperature window of 80–200 °C. • Rich Lewis acid sites and reactive oxygen species contributed to high SCR activity. • In-situ DRIFTS proved the SCR reaction process followed Langmuir-Hinshelwood route. A rational design of high dispersion MnO/Mn 3 O 4 catalysts based on carbon-acid hydrothermal strategy was proposed for selective catalytic reduction of NO at low temperature. The reaction mechanisms of low valence manganese coordination and catalytic path were revealed through active site analysis and in-situ DRIFTS characterization. The results showed that reasonable low valence manganese nanofibers cooperated to derive hierarchical mesoporous structure and abundant surface active oxygen. The chemisorbed oxygen specie cooperated with Lewis acid sites accelerated the production of NO 2 in the catalytic process and realized high-efficiency NO removal at ultra-low temperature. Such a facile preparation method of low valence manganese nanofibers structure widens the way for NH 3 -SCR of NO in industrial practice.

The multi-metal oxides blended activated coke for efficient NH3-SCR at super low-temperature

In order to solve the unsatisfactory NH3-SCR in the super low-temperature range (≤150 °C), the multi-metal oxides (CuO, MnO2 and Fe2O3) modified activated coke (AC) was prepared by using a one-step blending method. The results showed that the Cu6-Mn6-Fe1/AC exhibited a high NO conversion of 74.0% at 100 °C and performed good on N2 selectivity (97.0%). The metal oxides were successfully and uniformly dispersed on the surface and matrix of ACs. The blended metal oxide increased AC’s mesoporous structure, which was favorable to the mass transfer during SCR reaction. The amount of acidic functional groups, surface chemisorbed oxygen and lattice oxygen were greatly improved on Cu6-Mn6-Fe1/AC, and thus facilitated SCR reaction through E-R mechanism. These metals existed in a variety of valence states, and the catalytic reaction was achieved by electron transfer among these metals. Various spinels such as MnFe2O4, CuFe2O4 and CuMn2O4 were found in Cu6-Mn6-Fe1/AC, which not only enhanced SCR catalytic effect, but also was conducive to inhibiting N2O production and improving the anti-sulfur performance of SCR catalysts. While possessing high SCR catalytic effect at low temperature, the catalysts were convenient and efficient, which was promising in practical industrial application

A New Electrically Heated Mixer (EHM) for Efficient SCR of NOx in Low Load Cycles

&lt;div class="section abstract"&gt;&lt;div class="htmlview paragraph"&gt;Low temperature Diesel exhaust operations such as during low-load cycles are some of the most difficult conditions for SCR of NOx. This, along with newer regulations targeting substantial reduction of the tailpipe NOx such as California-2024/2027 NOx regulations, adds to challenges of high efficiency SCR of NOx in low temperature operations. A novel design, low-cost, low-energy Electrically Heated Mixer (EHM™), energized via the 12, 24 or 48 V vehicle electrical system, is used to accelerate formation of reductants (ammonia, isocyanic acid) in low temperature exhaust (low load cycles), so to enable high efficiency SCR of NOx in most challenging SCR conditions, while also mitigating urea deposit formation. EHM™ is also used to heat the cooler exhaust flow during engine cold-start. It easily fits common exhaust configurations and can be utilized on light, medium or heavy duty Diesel aftertreatment systems, on- or non-road or in stationary systems.&lt;/div&gt;&lt;/div&gt;

Excellent low temperature NH3-SCR and NH3-SCO performance over Ag-Mn/Ce-Ti catalyst: Evaluation and characterization

Low temperature SCR has been a promising technology due to the diverse load in coal-fired plants. However, ammonia escape problem could be more serious at low temperature on account of the condensation of NH4HSO4, resulting in deactivation of SCR catalyst and equipment corrosion. NH3-SCO technology could oxidize slip ammonia to harmless N2. Hence, it is important to develop a novel catalyst with high SCR and SCO efficiency at low temperature to remove NOx and slip NH3 and achieve the stable operation of SCR system. In this work, a combined sol-gel and impregnation method was used to synthetize different Aga−Mn/Ce-Ti (a = 2%, 5%, 8%) catalysts and applied in NOx and slip NH3 removal at low temperature. The activity measurement confirmed that Ag5-Mn/Ce-Ti catalyst exhibited an excellent low-temperature performance. At 150–300 °C, its NO conversion was 100%, NH3 conversion was above 95% and N2 selectivity was more than 90%. Moreover, considering the oxidation of slip ammonia, Ag5-Mn/Ce-Ti catalyst also exhibited above 90% NH3 conversion at 200–350 °C in the absence of NO. The catalytic performance could also be kept at a high level under the existence of SO2 and H2O. The characteristic results revealed that Ag and Mn modification could not apparently change the phase structure and could decrease the BET area to some extent. In addition, Ag-Mn/Ce-Ti catalyst possessed stronger and more surface acidic sites and contributed to better NH3 adsorption capacity. Besides, there was more chemisorbed oxygen on Ag-Mn/Ce-Ti catalyst resulting from the interactions among Ag, Mn and Ce oxides, which was responsible for its better redox property.

Investigating small-disturbance stability in power systems with grid-following and grid-forming VSCs using hybrid modelling approaches

The mass integration of power electronics-based devices is changing small-disturbance stability issues in power systems from primarily interactions between synchronous generators to include interactions between power electronic devices and the AC network. However, modelling of AC networks for small-disturbance stability assessment in large power systems generally do not include the transmission network dynamics and, therefore, fails to identify these newly emerging power phenomena. A suggested solution is the hybrid modelling approach which models the vicinity around the power electronics with network dynamics while representing the remainder of the network with a steady-state model. This paper identifies the most appropriate selection of dynamic AC network modelling in accordance with different scenarios including different power electronic control schemes, different power electronic operation modes, and different locations of power electronic devices. It is shown that more of the network must be modelled dynamically when VSCs are located in low SCR regions, operating in inverting mode, and using grid following or grid-forming control with inner current control explicitly modelled. Contrastingly, less dynamic detail is required for high SCR regions, rectifying mode, and when modelling grid forming control without explicit representation of the inner current controllers. Investigations are performed using the IEEE 39-bus test system.

Renal recovery after acute kidney injury requiring urgent hemodialysis is not associated with improved survival of the patients with multiple myeloma.

Severe acute kidney injury (AKI) requiring urgent hemodialysis (uHD) is associated with considerable morbidity and mortality in patients with multiple myeloma (MM). To evaluate the renal function, outcome, and survival status of patients with MM who received uHD and to compare their overall survival with MM patients who did not receive uHD. A total of 70 eligible MM patients who received uHD were included together with 70 control patients with MM. In the study group, 11 patients (15.7%) were known to have pre-existing chronic kidney disease. Thirty-four percent of the study group had AKI requiring uHD at MM diagnosis. Seventy-eight percent of the study group had severe AKI due to myeloma kidney. Renal function recovered in 36 patients (51.4%). Patients with MM who became hemodialysis dependent had significantly higher serum creatinine (sCr) levels at the time of AKI compared to patients with renal recovery (p < 0.05). Logistic regression analysis showed that high sCr on admission was significantly associated with hemodialysis dependence (odds ratio 0.78; 95% CI: 0.63-0.96; p = 0.018). The median overall survival was 30months [IQR: 26] in the study group and 84months [IQR: 96.25] in the control group (p < 0.05). Cox regression analysis showed that the need for uHD at initial MM diagnosis was associated with reduced survival (hazard ratio (HR) 1.9; 95% CI: 1.1-3.2; p = 0.017). Renal recovery did not provide a survival benefit. The need for uHD was associated with poor survival. Recovery of renal function was not associated with improved survival.

Study on the kinetics of the adsorption and desorption of NH3 on Fe/HBEA zeolite.

In this work, a Fe/HBEA zeolite (Si/Al: 12.5), representing an effective catalyst for the NH3-SCR process, was physico-chemically characterized and investigated regarding the kinetics of the adsorption and desorption of NH3. The sample was evaluated by N2 physisorption, 57Fe Möessbauer and DRUV-Vis spectroscopy, while the kinetics was investigated by temperature-programmed desorption of NH3 (TPD) including different adsorption temperatures. It was shown that the NH3 chemisorption results in weakly and strongly bonded molecular ammonia as well as ammonium species. A kinetic mean field model was developed implying two different types of adsorbates reflecting low (<ca. 200 °C) and high temperature desorption of NH3 (>ca. 200 °C). Kinetic parameters and surface coverages were obtained from numeric fits of the TPD curves, whereas pre-exponential factors of adsorption were deduced from the kinetic gas theory. As a result, the activation energy for the NHx adsorbate decomposition in the low temperature regime, which is assigned to single and double bonded ammonium species was determined to be 106 kJ mol-1. The NH3 desorption at higher temperatures referred to an activation energy of 133 kJ mol-1 predominately related to NH3 coordinated to Lewis acid surface sites and to some extent to stabilized NH4+ species. For validation of the kinetic model, experiments were simulated including NH3 adsorption at different temperatures, subsequent flushing with N2 and final TPD. Additionally, the consistency of the activation energies with the thermodynamic data was checked using differential scanning calorimetry and a van't Hoff approach.

Individualized prediction for the occurrence of acute kidney injury during the first postoperative week following cardiac surgery

Study objectiveTo develop individualized dynamic predictions for the occurrence of acute kidney injury (AKI) during the first postoperative week after cardiac surgery. DesignObservational retrospective cohort study. SettingSingle university teaching hospital in Madrid, Spain. Patients3960 cases of major cardiac surgery performed from January 2002 to December 2013. MeasurementsBaseline demographic and clinical characteristics, intraoperative risk factors, and repeated postoperative estimated glomerular filtration rates (eGFR). The primary outcome was AKI during the first postoperative week (stage 1 or higher of the Acute Kidney Injury Network). The dataset was split in two random samples (exploratory and validation). By combining time-to-event outcomes (AKI), and longitudinal data (repeated postoperative eGFR), we developed two different joint models for patients with normal and high baseline levels of serum creatinine (sCr). Main resultsAKI occurred in 1105 patients (31%, 95% confidence interval [CI] 29.5–32.5) in the exploratory sample and 128 (32.2%, 95% CI 27.6–36.8) in the validation sample. For high baseline sCr patients, the risk of an AKI event was associated with the eGFR trajectory (hazard ratio [HR] 0.91, 95% CI 0.90–0.92), as well as with age, and cardiopulmonary bypass time. The normal baseline sCr model incorporated the same covariates and intraoperative transfusion. In this second model, the risk of an AKI event was associated with both the eGFR trajectory (HR 0.91, 95% CI 0.91–0.92, for the current value of eGFR), and with its slope at that point (HR 0.96, 95% CI 0.94–0.99). So AKI risk decreased when the eGFR values increased, in accordance with the speed of this rise. Internal validation showed good discrimination and calibration of both joint models. The AUCs were always higher than 0.7. ConclusionsThe joint models obtained combining both patient risk factors and postoperative eGFR values, are useful to predict individualized risk of cardiac surgery-associated AKI. Predictions can be updated as new information is gathered.