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Materials (Basel, Switzerland) Jun 2024In industrial production, the deformation inhomogeneity after metal forging affects the mechanical properties of various parts of the forgings. The question of whether...
In industrial production, the deformation inhomogeneity after metal forging affects the mechanical properties of various parts of the forgings. The question of whether the organization and mechanical properties of β-titanium alloy can be improved by controlling the amount of forging deformation needs to be answered. Therefore, in this paper, a new sub-stable β-Ti alloy TB 18 (Ti-5.3Cr-4.9Mo4.9V-4.3Al-0.9Nb-0.3Fe) was subjected to three different levels of deformation, as well as solid solution-aging treatments, and the variation rules of microstructure and mechanical properties were investigated. During the solid solution process, the texture evolution pattern of the TB18 alloy at low deformation (20-40%) is mainly rotational cubic texture deviated into α-fiber texture; at high deformation (60%), the main components of the deformed texture are α-fiber texture with a specific orientation of (114)<113-3>. After subsequent static recrystallization, the α-fiber texture is deviated to an α*-fiber texture, while the specific orientation (114)<113-3> can still be inherited as a major component of the recrystallized texture. The plasticity of the alloy in the normal direction (ND) after the solid solution is influenced by the existence of the <110>//ND texture, and the plasticity of the alloy in the ND direction after aging is determined by a combination of the volume fraction of the <110>//ND texture in the matrix phase and the volume fraction of [112-0]//ND in the α phase. The results show that it is feasible to change the characteristics of the recrystallization texture of TB18 by controlling the deformation level of hot forging, thus realizing the modulation of the mechanical properties.
PubMed: 38930202
DOI: 10.3390/ma17122828 -
Materials (Basel, Switzerland) Jun 2024Cyclic heat treatment is an effective approach for enhancing the mechanical properties of 18Ni(C250) maraging steel, and the selection of cyclic heat treatment...
Cyclic heat treatment is an effective approach for enhancing the mechanical properties of 18Ni(C250) maraging steel, and the selection of cyclic heat treatment temperature is a key factor. In this study, a cyclic heat treatment process with a two-step solution treatment is employed to investigate the influence of cyclic heat treatment temperature, specifically the first solution treatment temperature (920 °C, 950 °C, and 980 °C), on the microstructure and mechanical properties of 18Ni(C250) maraging steel. The results indicate that with an increase in the cyclic heat treatment temperature, the average grain size of the 18Ni(C250) maraging steel decreases initially and then increases. When the cyclic heat treatment temperature reaches 950 °C, the grain size is at its minimum, exhibiting optimal grain uniformity. Additionally, the increase in cyclic heat treatment temperature results in a reduction in the size of martensitic lath with the same orientation inside the grains, along with an increase in the relative quantity of low-angle grain boundaries. Furthermore, the volume fraction and size of retained austenite show a monotonous increase with the rise in the temperature of the cyclic heat treatment, and the rate of increase becomes notably larger when the temperature is raised from 950 °C to 980 °C. Based on the observed microstructural changes, the variation in the mechanical properties of the 18Ni(C250) maraging steel was analyzed. Specifically, as the cyclic heat treatment temperature increases, the tensile strength of the 18Ni(C250) maraging steel initially increases and then stabilizes, while the elongation and fracture toughness exhibit a monotonic increase.
PubMed: 38930166
DOI: 10.3390/ma17122796 -
Journal of Clinical Medicine Jun 2024: Medulloblastoma is the most common malignant brain tumor in children. In recent decades, the therapeutic landscape has undergone significant changes, with stereotactic...
: Medulloblastoma is the most common malignant brain tumor in children. In recent decades, the therapeutic landscape has undergone significant changes, with stereotactic radiosurgery (SRS) emerging as a promising treatment for recurrent cases. Our study provides a comprehensive analysis of the long-term efficacy and safety of SRS in recurrent medulloblastomas across both pediatric and adult patients at a single institution. : We retrospectively reviewed the clinical and radiological records of patients who underwent CyberKnife SRS for recurrent cranial medulloblastomas at our institution between 1998 and 2023. Follow-up data were available for 15 medulloblastomas in 10 patients. The cohort comprised eight pediatric patients (ages 3-18) and two adult patients (ages 19-75). The median age at the time of SRS was 13 years, the median tumor volume accounted for 1.9 cc, the median biologically equivalent dose (BED) was 126 Gy, and the single-fraction equivalent dose (SFED) was 18 Gy. The SRS was administered at 75% of the median isodose line. : Following a median follow-up of 39 months (range: 6-78), 53.3% of the medulloblastomas progressed, 13.3% regressed, and 33.3% remained stable. The 3-year local tumor control (LTC) rate for all medulloblastomas was 65%, with lower rates observed in the adult cohort (50%) and higher rates in pediatric patients (67%). The 3-year overall survival (OS) rate was 70%, with significantly higher rates in pediatric patients (75%) compared to adult patients (50%). The 3-year progression-free survival (PFS) rate was 58.3%, with higher rates in pediatric patients (60%) compared to adult patients (50%). Two pediatric patients developed radiation-induced edema, while two adult patients experienced radiation necrosis at the latest follow-up, with both adult patients passing away. : Our study provides a complex perspective on the efficacy and safety of CyberKnife SRS in treating recurrent cranial medulloblastomas across pediatric and adult populations. The rarity of adverse radiation events (AREs) underscores the safety profile of SRS, reinforcing its role in enhancing treatment outcomes. The intricacies of symptomatic outcomes, intertwined with factors such as age, tumor location, and prior surgeries, emphasize the need for personalized treatment approaches. Our findings underscore the imperative for ongoing research and the development of more refined treatment strategies for recurrent medulloblastomas. Given the observed disparities in treatment outcomes, a more meticulous tailoring of treatment approaches becomes crucial.
PubMed: 38930121
DOI: 10.3390/jcm13123592 -
Journal of Clinical Medicine Jun 2024Rest and stress echocardiography (SE) play a fundamental role in the evaluation of aortic valve stenosis (AS). According to the current guidelines for the... (Review)
Review
Rest and stress echocardiography (SE) play a fundamental role in the evaluation of aortic valve stenosis (AS). According to the current guidelines for the echocardiographic evaluation of patients with aortic stenosis, four broad categories can be defined: high-gradient AS (mean gradient ≥ 40 mmHg, peak velocity ≥ 4 m/s, aortic valve area (AVA) ≤ 1 cm or indexed AVA ≤ 0.6 cm/m); low-flow, low-gradient AS with reduced ejection fraction (mean gradient < 40 mmHg, AVA ≤ 1 cm, left ventricle ejection fraction (LVEF) < 50%, stroke volume index (Svi) ≤ 35 mL/m); low-flow, low-gradient AS with preserved ejection fraction (mean gradient < 40 mmHg, AVA ≤ 1 cm, LVEF ≥ 50%, SVi ≤ 35 mL/m); and normal-flow, low-gradient AS with preserved ejection fraction (mean gradient < 40 mmHg, AVA ≤ 1 cm, indexed AVA ≤ 0.6 cm/m, LVEF ≥ 50%, SVi > 35 mL/m). Aortic valve replacement (AVR) is indicated with the onset of symptoms development or LVEF reduction. However, there is often mismatch between resting transthoracic echocardiography findings and patient's symptoms. In these discordant cases, SE and CT calcium scoring are among the indicated methods to guide the management decision making. Additionally, due to the increasing evidence that in asymptomatic severe aortic stenosis an early AVR instead of conservative treatment is associated with better outcomes, SE can help identify those that would benefit from an early AVR by revealing markers of poor prognosis. Low-flow, low-gradient AS represents a challenge both in diagnosis and in therapeutic management. Low-dose dobutamine SE is the recommended method to distinguish true-severe from pseudo-severe stenosis and assess the existence of flow (contractile) reserve to appropriately guide the need for intervention in these patients.
PubMed: 38930024
DOI: 10.3390/jcm13123495 -
Foods (Basel, Switzerland) Jun 2024Its high dietary fiber and protein contents and nutritional quality make defatted wheat germ (DWG) a valuable cereal by-product, yet its negative impact on food...
Its high dietary fiber and protein contents and nutritional quality make defatted wheat germ (DWG) a valuable cereal by-product, yet its negative impact on food structure limits its use as a food ingredient. In this research, DWG underwent air classification, which identified two fractions with high fiber (HF) and low fiber/high protein (LF) contents, and a bioprocessing protocol, involving treatment with xylanase and fermentation with selected lactic acid bacterial strains. The degree of proteolysis was evaluated through electrophoretic and chromatographic techniques, revealing differences among fractions and bioprocessing options. Fermentation led to a significant increase in free amino acids (up to 6 g/kg), further enhanced by the combination with xylanase. When HF was used as an ingredient in bread making, the fiber content of the resulting bread exceeded 3.6 g/100 g, thus reaching the threshold required to make a "source of fiber" claim according to Regulation EC No.1924/2006. Meanwhile, all breads could be labeled a "source of protein" since up to 13% of the energy was provided by proteins. Overall, bioprocessed ingredients lowered the glycemic index (84 vs. 89) and increased protein digestibility (80 vs. 63%) compared to control breads. Technological and sensory analysis showed that the enzymatic treatment combined with fermentation also conferred a darker and more pleasant color to the bread crust, as well as better crumb porosity and elasticity.
PubMed: 38928894
DOI: 10.3390/foods13121953 -
Foods (Basel, Switzerland) Jun 2024Clarification and stabilisation processes are routinely performed post-fermentation to 'finish' wines, but traditional methods are slow and energy intensive, create...
Clarification and stabilisation processes are routinely performed post-fermentation to 'finish' wines, but traditional methods are slow and energy intensive, create waste, and can affect wine volume and quality. New methods that 'finish' wine rapidly, with higher recovery rates, and reduced waste and input costs, are therefore needed. Ultrafiltration is a separation process that fractionates liquids, nominally, according to molecular weight. By comparing the composition of permeate and retentate derived from pilot-scale fractionation of white and red wine using 75, 20, or 10 kDa membranes and different degrees of permeation (50, 80, 90, or 95%), this study sought to evaluate ultrafiltration as an innovative approach to the clarification and stabilisation of wine. Mass balance analysis confirmed that titratable acidity and alcohol were fractionated according to the degree of permeation; however, proteins, polysaccharides, and phenolic compounds (including anthocyanins for red wine) were concentrated in retentate due both to the membrane molecular weight cut-off (MWCO) specifications and degree of permeation. The retention of wine constituents smaller than the nominal MWCO suggests that interaction with other macromolecules or the membrane surface occurred. Red wine permeates were stripped of much of their essential character and were no longer considered commercially acceptable. In contrast, the removal of protein and phenolic compounds from white wine demonstrated the potential for ultrafiltration to remediate heat unstable or excessively phenolic wines. Findings enabled the identification of other winemaking applications of ultrafiltration technology that could enhance wine quality, process efficiency, and profitability.
PubMed: 38928792
DOI: 10.3390/foods13121850 -
Diagnostics (Basel, Switzerland) Jun 2024Overhydration and cardiac function abnormalities are common in hemodialysis patients. The association of N-terminal prohormone for brain natriuretic peptide (NT-proBNP)...
Overhydration and cardiac function abnormalities are common in hemodialysis patients. The association of N-terminal prohormone for brain natriuretic peptide (NT-proBNP) and other fluid status biomarkers with echocardiographic parameters of heart failure with preserved ejection fraction (HFpEF) is scarcely investigated in this population. A total of 100 separate measurements performed in 50 dialysis patients (29 male, aged 60 ± 17 years) in NYHA class II/II and preserved left ventricle ejection fraction were analyzed. Plasma levels of NT-proBNP, mid-regional prohormone for atrial natriuretic peptide (MR-proANP) and copeptin (CPP) were measured. The E/e' ratio as an index of HFpEF and other echocardiographic parameters were calculated. An E/e' ratio >9 was associated with higher median right ventricular systolic pressure (RVSP) and LVMI values. Left atrium volume index (LAVI) as well as NT-proBNP and MR-proANP, but not CPP levels were significantly higher in this group. In a stepwise multivariate analysis, only CPP and IL-6 levels were found to be independently associated with the E/e' ratio in the study group, whereas NT-proBNP and MR-proANP were associated only with left heart structure parameters and LVEF. Of the analyzed biomarkers, only the CPP level was found to be independently associated with the E/e' ratio in maintenance hemodialysis patients.
PubMed: 38928725
DOI: 10.3390/diagnostics14121310 -
Diagnostics (Basel, Switzerland) Jun 2024This study assesses the predictive performance of six machine learning models and a 1D Convolutional Neural Network (CNN) in forecasting tumor dynamics within three...
This study assesses the predictive performance of six machine learning models and a 1D Convolutional Neural Network (CNN) in forecasting tumor dynamics within three months following Gamma Knife radiosurgery (GKRS) in 77 brain metastasis (BM) patients. The analysis meticulously evaluates each model before and after hyperparameter tuning, utilizing accuracy, AUC, and other metrics derived from confusion matrices. The CNN model showcased notable performance with an accuracy of 98% and an AUC of 0.97, effectively complementing the broader model analysis. Initial findings highlighted that XGBoost significantly outperformed other models with an accuracy of 0.95 and an AUC of 0.95 before tuning. Post-tuning, the Support Vector Machine (SVM) demonstrated the most substantial improvement, achieving an accuracy of 0.98 and an AUC of 0.98. Conversely, XGBoost showed a decline in performance after tuning, indicating potential overfitting. The study also explores feature importance across models, noting that features like "control at one year", "age of the patient", and "beam-on time for volume V1 treated" were consistently influential across various models, albeit their impacts were interpreted differently depending on the model's underlying mechanics. This comprehensive evaluation not only underscores the importance of model selection and hyperparameter tuning but also highlights the practical implications in medical diagnostic scenarios, where the accuracy of positive predictions can be crucial. Our research explores the effects of staged Gamma Knife radiosurgery (GKRS) on larger tumors, revealing no significant outcome differences across protocols. It uniquely considers the impact of beam-on time and fraction intervals on treatment efficacy. However, the investigation is limited by a small patient cohort and data from a single institution, suggesting the need for future multicenter research.
PubMed: 38928683
DOI: 10.3390/diagnostics14121268 -
International Journal of Molecular... Jun 2024Treatment of critically ill patients with venovenous (V-V) extracorporeal membrane oxygenation (ECMO) has gained wide acceptance in the last few decades. However, the...
New Insights into Hepatic and Intestinal Microcirculation and Pulmonary Inflammation in a Model of Septic Shock and Venovenous Extracorporeal Membrane Oxygenation in the Rat.
Treatment of critically ill patients with venovenous (V-V) extracorporeal membrane oxygenation (ECMO) has gained wide acceptance in the last few decades. However, the use of V-V ECMO in septic shock remains controversial. The effect of ECMO-induced inflammation on the microcirculation of the intestine, liver, and critically damaged lungs is unknown. Therefore, the aim of this study was to measure the hepatic and intestinal microcirculation and pulmonary inflammatory response in a model of V-V ECMO and septic shock in the rat. Twenty male Lewis rats were randomly assigned to receive V-V ECMO therapy or a sham procedure. Hemodynamic data were measured by a pressure-volume catheter in the left ventricle and a catheter in the lateral tail artery. Septic shock was induced by the intravenous infusion of lipopolysaccharide (1 mg/kg). During V-V ECMO therapy, rats received lung-protective ventilation. The hepatic and intestinal microcirculation was assessed by micro-lightguide spectrophotometry after median laparotomy for 2 h. Systemic and pulmonary inflammation was measured by enzyme-linked immunosorbent assays of plasma and bronchoalveolar lavage (BAL), respectively, which included tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6), IL-10, C-X-C motif ligand 2 (CXCL2), and CXCL5. Reduced oxygen saturation and relative hemoglobin concentration were measured in the hepatic and intestinal microcirculation during treatment with V-V ECMO. These animals also showed increased systolic, mean, and diastolic blood pressures. While no differences in left ventricular ejection fraction were observed, animals in the V-V ECMO group presented an increased heart rate, stroke volume, and cardiac output. Blood gas analysis showed dilutional anemia during V-V ECMO, whereas plasma analysis revealed a decreased concentration of IL-10 during V-V ECMO therapy, and BAL measurements showed increased concentrations of TNF-α, CXCL2, and CXCL5. Rats treated with V-V ECMO showed impaired microcirculation of the intestine and liver during septic shock despite increased blood pressure and cardiac output. Despite lung-protective ventilation, increased pulmonary inflammation was recognized during V-V ECMO therapy in septic shock.
Topics: Animals; Microcirculation; Extracorporeal Membrane Oxygenation; Male; Rats; Shock, Septic; Rats, Inbred Lew; Intestines; Liver; Disease Models, Animal; Pneumonia; Hemodynamics; Tumor Necrosis Factor-alpha
PubMed: 38928327
DOI: 10.3390/ijms25126621 -
International Journal of Molecular... Jun 2024Heart failure with preserved ejection fraction (HFpEF) is characterized by biomechanically dysfunctional cardiomyocytes. Underlying cellular changes include perturbed...
Heart failure with preserved ejection fraction (HFpEF) is characterized by biomechanically dysfunctional cardiomyocytes. Underlying cellular changes include perturbed myocardial titin expression and titin hypophosphorylation leading to titin filament stiffening. Beside these well-studied alterations at the cardiomyocyte level, exercise intolerance is another hallmark of HFpEF caused by molecular alterations in skeletal muscle (SKM). Currently, there is a lack of data regarding titin modulation in the SKM of HFpEF. Therefore, the aim of the present study was to analyze molecular alterations in limb SKM (tibialis anterior (TA)) and in the diaphragm (Dia), as a more central SKM, with a focus on titin, titin phosphorylation, and contraction-regulating proteins. This study was performed with muscle tissue, obtained from 32-week old female ZSF-1 rats, an established a HFpEF rat model. Our results showed a hyperphosphorylation of titin in limb SKM, based on enhanced phosphorylation at the PEVK region, which is known to lead to titin filament stiffening. This hyperphosphorylation could be reversed by high-intensity interval training (HIIT). Additionally, a negative correlation occurring between the phosphorylation state of titin and the muscle force in the limb SKM was evident. For the Dia, no alterations in the phosphorylation state of titin could be detected. Supported by data of previous studies, this suggests an exercise effect of the Dia in HFpEF. Regarding the expression of contraction regulating proteins, significant differences between Dia and limb SKM could be detected, supporting muscle atrophy and dysfunction in limb SKM, but not in the Dia. Altogether, these data suggest a correlation between titin stiffening and the appearance of exercise intolerance in HFpEF, as well as a differential regulation between different SKM groups.
Topics: Animals; Heart Failure; Rats; Diaphragm; Connectin; Phosphorylation; Disease Models, Animal; Female; Muscle, Skeletal; Stroke Volume; Muscle Contraction; Physical Conditioning, Animal; Muscle Proteins
PubMed: 38928324
DOI: 10.3390/ijms25126618