Early creatinine changes after aortic valve replacement and late survival, heart failure and chronic kidney disease in a national registry.

BACKGROUND: The impact of small increases in serum-creatinine after surgical aortic valve replacement (SAVR) that fail to meet the acute kidney injury stage 1 criteria is unknown. The aim was to investigate prognosis after primary SAVR in patients with small increases in postoperative serum-creatinine. METHODS: In this observational cohort study, we included all adult patients who underwent primary SAVR in Sweden 2009-2022. The main outcome was all-cause mortality. Secondary outcomes were chronic kidney disease and heart failure. Regression standardization addressed confounding. RESULTS: In 16,766 patients, 4,074 (24.2%) had no change in postoperative serum-creatinine, 5,764 (34.3%) had a small increase in postoperative serum-creatinine (0.06 mg/dL≤Δserum-creatinine<0.3 mg/dL), and 2,753 (16.4%) fulfilled the KDIGO acute kidney injury stage 1 criteria. The mean age was 67 years and 31% were female. No significant difference in long-term all-cause mortality was observed in the no-change group at 13 years compared with the small-increase group (absolute survival difference: 2.3% (95%CI: 0-4.6)). A stepwise increase in the risk of 30-day mortality was observed with increasing change in serum-creatinine. At 13 years of follow-up, there was a significant difference in the risk of chronic kidney disease (absolute difference: 2.8% (95%CI: 1.0-4.5)) and heart failure (absolute difference: 3.5% (95%CI: 1.3-5.7)) between the no-change and small-increase groups. CONCLUSIONS: A small increase in postoperative serum-creatinine after SAVR was associated with increased risk of adverse outcomes. The acute kidney injury definition may benefit from including more reliable and specific biomarkers together with small creatinine increases to detect kidney injury.

A computational study of cell membrane damage and intracellular delivery in a cross-slot microchannel.

We propose a three-dimensional computational framework to simulate the flow-induced cell membrane damage and the resulting enhanced intracellular mass transport in a cross-slot microchannel. We model the cell as a liquid droplet enclosed by a viscoelastic membrane and solve the cell deformation using a well-tested immersed-boundary lattice-Boltzmann method. The cell membrane damage, which is directly related to the membrane permeability, is considered using continuum damage mechanics. The transport of the diffusive solute into the cell is solved by a lattice-Boltzmann model. After validating the computational framework against several benchmark cases, we consider a cell flowing through a cross-slot microchannel, focusing on the effects of the flow strength, channel fluid viscosity and cell membrane viscosity on the membrane damage and enhanced intracellular transport. Interestingly, we find that under a comparable pressure drop across the device, for cells with low membrane viscosity, the inertial flow regime, which can be achieved by driving a low-viscosity liquid at a high speed, often leads to much larger membrane damage, compared with the high-viscosity low-speed viscous flow regime. However, the enhancement can be significantly reduced or even reversed by an increase of the cell membrane viscosity, which limits cell deformation, particularly in the inertial flow regime. Our computational framework and simulation results may guide the design and optimisation of microfluidic devices, which use cross-slot geometry to disrupt cell membranes to enhance intracellular delivery of solutes.

Spacecraft Segment Damage Identification Method Based on Fiber Optic Strain Difference Field Reconstruction and Norm Calculation.

Real-time online identification of spacecraft segment damage is of great significance for realizing spacecraft structural health monitoring and life prediction. In this paper, a damage response characteristic field inversion algorithm based on the differential reconstruction of strain response is proposed to solve the problem of not being able to recognize the small damages of spacecraft structure directly by the strain response alone. Four crack damage location identification methods based on vector norm computation are proposed, which realize online identification and precise location of structural damage events without external excitation by means of spacecraft structural working loads only. A spacecraft segment structural damage monitoring system based on fiber optic grating sensors was constructed, and the average error of damage localization based on the curvature vector 2 norm calculation was 2.58 mm, and the root-mean-square error was 1.98 mm. The results show that the method has superior engineering applicability for on-orbit service environments.

Aortic Valve Replacement With Mechanical Valves vs Perimount Bioprostheses in 50- to 69-Year-Old Patients.

Background: Evidence is mixed regarding the most appropriate type of valve prosthesis for surgical aortic valve replacement (AVR) in patients 50 to 69 years. American and European guidelines differ. Objectives: The purpose of this study was to determine the long-term all-cause mortality and complication rates after AVR in patients aged 50 to 69 years according to implantation of a Perimount bioprosthetic valve or a mechanical valve. Methods: In this nationwide observational cohort study, all patients aged 50 to 69 years who underwent primary surgical AVR in Sweden 2003 to 2018 using a Perimount bioprosthesis or mechanical valve were identified from the SWEDEHEART register. Primary outcome; all-cause mortality, secondary outcomes; major bleeding, aortic valve reintervention, heart failure hospitalization, and stroke. National health-data registers were used to ascertain outcomes. Regression standardization addressed confounding. Results: A total of 6,907 patients aged 50 to 69 years were included (Perimount group, n = 3,831 and mechanical valve group, n = 3,076) and 74% were men. The use of bioprostheses increased during the study period. At 15 years of follow-up, the estimated cumulative incidence of all-cause mortality was 37% (95% CI: 35%-40%) vs 45% (95% CI: 42%-48%) in the mechanical and Perimount groups, respectively (survival difference -7.9% [95% CI: -11% to -4.6%]). Patients with mechanical valves had a lower risk of aortic valve reintervention but a higher risk for bleeding. Survival difference at 15 years in ages 50 to 59 years was -15% (95% CI: -8.4% to -21%). Conclusions: In patients aged 50 to 69 years who underwent surgical AVR, survival was better in those who received mechanical compared to Perimount bioprosthetic valves. While valve choice should be guided by individual patient factors and patient preference rather than by chronological age, the substantial survival advantage observed in patients with mechanical valves in ages 50 to 59 years must be recognized.

Insight into the photocatalytic mechanism of the optimal x value in the BiOBrxI1-x, BiOClxI1-x and BiOClxBr1-x series varying with pollutant type.

It is known that bismuth oxyhalides (BiOX, X = Cl, Br, I) can easily form solid solutions like BiOBrxI1-x, BiOClxI1-x and BiOClxBr1-x (0 ≤ x ≤ 1) and exhibit composition-dependent photocatalytic performance. However, the reported results indicate that the optimal composition changes with pollutant type. That is to say, the specific x value with the best photocatalytic activity towards the degradation of a certain pollutant does not imply that it is an optimum x value for another pollutant. In order to explore the reason behind this, herein, three types of solid solutions with various x values were prepared in ethylene glycol/H2O (VEG : VH2O = 1) solution at room temperature, and their photocatalytic activity towards the degradation of bisphenol A (BPA), tetracycline (TC), malachite green (MG), methyl violet (MV) and rhodamine B (RhB) was assessed under visible-light illumination. Taking BiOBrxI1-x as an example, BiOBr0.5I0.5 exhibited the best degradation efficiency for BPA, MV and MG, whereas BiOBr0.95I0.05 possessed the best photocatalytic activity towards TC and RhB degradation. Detailed characterization suggests that light absorption and charge separation efficiency are not the main factors behind this difference. Given that direct oxidation of the holes was dominant in the degradation process, the oxidation ability of the solid solutions was correlated with the oxidation behavior of the pollutant. The prerequisite condition for degrading a certain pollutant is that the valence band potential of the solid solution should be more positive than the oxidation potential of the pollutant, and yet, too big a difference between these two potentials does not benefit rapid degradation.

[Screening of anti-diarrhea effective fractions from guava leaf].

OBJECTIVE: To screen the fractions from guava leaf to ascertain the effective anti-diarrhea fraction and to establish the method of quality control. METHODS: A series of samples from guava leaf were prepared through extraction and separation by solvents progressively, and their effect on the mice diarrhea models induced by senna decoction were tested individually; and the constituent correlated with the effect of the samples on the models was determined by HPLC. RESULTS: The effect of the fractions with moderate-polar glucosides from guava leaf was better than that of the other fractions; the effect of the fractions with the glucosides was correlated with the content of the quercetin glucosides in the fractions. CONCLUSION: The fractions with the moderate-polar glucosides is the effective anti-diarrhea fraction of guava leaf; determination of the quercetin glucosides can be used for quality control of guava leaf and its extracts.

[Study on extraction of quercetin in guava leaf by microemulsion].

OBJECTIVE: To study the extraction of quercetin in guava leaf by microemulsion. METHODS: The optimal component proportion was obtained by investigating the ratio of oil, water, surfactant and cosurfactant. The extraction of quercetin in microemulsion was determined by HPLC which compared with the traditional method. RESULTS: The traditional solvent extraction methods were used to extract quercetin in guava leaf, and the content of quercetin extracted with methanol was the highest (4.72 microg/mL). But the contents of quercetin extracted by 72 percent of the microemulsions were higher than methanol, and the extraction by the optimum formulation of microemulsion which consisted of acetoacetate (oil phase) -30% avantin solution (water phase) -RH60 (surfactant) was 2 times as much as that was extracted by methanol (10.43 microg/mL). CONCLUSION: Compared with traditional solvent extraction methods, microemulsion method can effectively improve the extraction rate of quercetin in guava leaf.