Evaluation of Hemodynamic Alterations after Flow Diverter Placement using the AneurysmFlowTM tool.

Background: AneurysmFlow (Phillips Healthcare) is the flow measurement tool, utilizing an optical flow-based algorithm from DSA, lacks sufficient published studies. This study aimed to assess the significance of flow velocity changes and the Mean Aneurysm Flow Amplitude (MAFA) ratio in evaluating outcomes following flow-diverting treatments. Methods: Between June 2021 and October 2022, 41 patients with 42 aneurysms underwent FDS treatment with AneurysmFlow measu-rement at the Bach Mai Radiology Center. Results: The tool achieved a 90.5% success rate in 38 out of 42 patients. Most aneurysms (89.5%) were small to medium-sized (<10 mm), and a decrease in flow velocity post-stent deployment was ob-served in 78.9% of cases. Conversely, 21.1% showed increased flow, mainly in aneurysms smaller than 5 mm. No significant association was found between flow changes or MAFA ratio and aneurysm size characteristics. Twenty-two patients (59.5%) underwent re-examination at 6 months, revealing no correlation in MAFA ratio between completely and incompletely occluded aneurysms. Conclusions: Our current investigation, primarily centered on small and medium-sized aneurysms, did not uncover any link between quantitative flow changes assessed using the AneurysmFlow software and the occlusion status of aneurysms at the 6-month follow-up post-flow diverter treatment. Larger case series with extended follow-up imaging are necessary to further explore these findings.

Balloon Angioplasty with or without Stenting for Acute Intracranial Atherothrombosis.

Objectives: Due to limited evidence on the optimal strategy for acute atherothrombosis in a large intracranial vessel, we aimed to provide further evidence on the safety and efficacy of balloon angioplasty with or without stenting after failed thrombectomy. Materials & Methods: This single-center retrospective study was performed from June 2017 to February 2021. Patients with acute atherothrombosis in large intracranial vessels treated by balloon angioplasty with or without stenting after failed thrombectomy were enrolled and analyzed. Results: A total of 23 patients were recruited. All patients had a moderate stroke and the majority of them had ASPECTS ≥7 (82.6%). MCA was the most commonly affected artery (13 cases), followed by supraclinoid ICA (6 cases), and BA (4 cases). Balloon angioplasty was firstly performed in 15 cases, of which 8 cases required subsequent stenting. Intracranial stenting was firstly performed in 8 cases. Success-ful recanalization (TICI 2b-3) was achieved in 19/23 cases (82.6%) on the final angiogram. Perforated complications occurred in 1/23 cases (4.3%). Good outcome (mRS 0-2) at 90 days was achieved in 13/23 cases (56.5%) and the mortality rate was 4/23 cases (17.4%). The good clinical outcome rate was significantly higher in patients adapted with balloon angioplasty alone versus intracranial stenting. Conclusions: In the present study, balloon angioplasty with or without stenting was obsversed to be safe and efficient as a rescue therapy after failed thrombectomy for acute atherothrombosis in a large intracranial vessel. Balloon angioplasty should be the first choice and stenting should be performed later in refractory cases.

Effect of mechanical thrombectomy with vs. without intravenous thrombolysis in acute ischemic stroke.

Background: The results of mechanical thrombectomy (MT), wi-thout or with intravenous thrombolysis, were evaluated and compared in 178 patients with acute ischemic stroke (AIS) due to large vessel occlusions (LVO) at Bach Mai Hospital. Methods: A total of 178 patients with AIS due to LVO were assigned to undergo MT alone (MT-alone group) or MT preceded by intravenous alteplase (the combined group), at a dose of 0.9 mg per kilogram, administered within 4.5 hours after symptom onset (combined group). The successful recanalization rate (assessed as thrombolysis in cerebral infarction [TICI] classification of 2b-3) and the incidence of good clinical recovery outcomes (modified Rankin Scale [mRS] ≤2) after 3 months were analyzed in both groups and compared. Results: A total of 178 patients were enrolled (median age, 65 years; 55% men; median National Institutes of Health Stroke Scale [NIHSS]: 14.3). Favorable outcomes were reported in 76 patients (66.7%) in the MT-alone group and 42 patients (65.6%) in the com-bined group, with no significant between-group difference (P = 0.31 for noninferiority). However, MT alone was associated with a lower percentage of patients with successful reperfusion after MT compared with the combined group (87.7% vs. 90.6%). Mortality at 90 days was 12.2% (14 patients) in the MT-alone group and 17.2% (11 patients) in the combined group. The incidence of symptomatic intracerebral hemorrhage was not significantly different between groups (6 [5.3%] vs. 1 [1.6%]; P = 0.42). Conclusion: Among patients with AIS due to LVO in our study, MT alone was noninferior in terms of functional outcomes compared with MT preceded by the administration of intravenous alteplase within 4.5 hours after symptom onset.

Thrombectomy Alone versus Bridging Therapy in Acute Ischemic Stroke: Preliminary Results of an Experimental Trial.

Background: For patients with acute large vessel occlusion (ALVO) in the anterior circulation who are able to undergo mechani-cal thrombectomy (MTB) within 4.5 hours, the need for intravenous thrombolysis prior to the intervention remains unclear. Methods: Patients who were eligible for intravenous thrombolysis, who presented with ALVO in the anterior circulation, and who started MTB within 4.5 hours were matched at a 1:1 ratio to a thrombectomy alone group or to a bridging therapy group. Patients in the bridging therapy group were administered intravenous alteplase at a standard dose of 0.9 mg/kg. We evaluated the safety and efficacy of the throm-bectomy alone group compared with the bridging therapy group. Results: From December 2020 to September 2021, 60 patients were recruited in the study and completed the trial. The baseline para-meters of patients were similar between the two groups. At the 90-day follow-up, 18 patients (60%) in the thrombectomy alone group versus 18 patients (60%) in the bridging therapy group achieved functional independence (odds ratio [OR]: 1, 95% confidence interval [CI], 0.36-2.81). The successful recanalization (Thrombolysis in Cerebral Infarction [TICI] grade 2b to 3) rates on final angiography were 90% and 86.7%, respectively (OR, 0.72, 95% CI, 0.15-3.55). No significant differences were found between the two groups in the occurrence of symptomatic intracranial hemorrhage or 90-day mortality. Conclusion: Our preliminary results did not show the superiority of thrombectomy alone versus standard bridging therapy in patients with ALVO in the anterior circulation who undergo MTB within 4.5 hours. A larger sample size and other randomized controlled trials remain necessary to validate these results.

A universal kinetic model for characterisation of the effect of chip thickness on kraft pulping.

A kinetic model was developed to characterise the heterogeneous nature of kraft delignification kinetics, taking into account the effect of chip thickness. The final form of the model applied to kraft delignification can be represented by a first-order rate equation with a rate constant inversely proportional to a power function of chip thickness. Published laboratory results from kraft pulping of various lignocellulosic materials were used to validate the model. The outcomes confirm the significant effect of chip thickness on the delignification rate. The resultant model was used to predict the effect of chip thickness on the kappa distribution of kraft pulps.

Development of the photoacoustic rapid-scan FT-IR-based method for measurement of ink concentration on printed paper.

Photoacoustic rapid-scan FT-IR spectroscopy was used to collect spectra of paper samples printed with mineral- and vegetable-oil-based inks at different concentrations. Partial least-squares (PLS) analysis and principal component analysis (PCA) were combined to form a model that, with data collected in the 3600-3200, 3000-2800, and 1800-1000 cm-1 spectral regions, enables one to predict the concentration of ink in printed samples. Prediction is statistically robust provided the selected optical path difference (OPD) velocities are within the range 0.05-1.00 cm/s.

Effect of refining on pulp surface charge accessible to polydadmac and FTIR characteristic bands of high yield kraft fibres.

Studies were carried out to determine the surface charge and total charge of refined softwood high yield kraft pulps at different levels by titration methods. The results showed that the surface charge was highly dependent on the degree of refining. However, the total fibre charge was not affected by refining. The change of the fibre surface charge during refining monitored using ATR-FTIR characteristic bands was within 1700-1300 cm(-1). Reliable PLS1 calibration models could be established to correlate the FTIR spectral data and the surface charge of the refined pulps.

Thermodynamic aspects of sorption of Fe2+ onto unbleached Kraft fibres.

The sorption of Fe(2+) onto unbleached kraft fibre was investigated at different conditions such as pH, temperature, and concentrations. The sorption, which increased with concentration and temperature, followed the Langmuir isotherm. Thermodynamically, the process was spontaneous and endothermic. It was found that the precipitation of Fe(2+) was highly dependent on pH and reached 100% when pH exceeded approximately 8.

A comparative study of the effect of refining on physical and electrokinetic properties of various cellulosic fibres.

The aim of this work was to study the influence of refining on various pulp properties such as freeness, specific surface area, specific volume, surface charge, total charge and elastic modulus. The results indicated that specific surface area of the pulps increased with increased refining, and at the same freeness level the pine pulp exhibited higher surface charge, surface area, and specific volume than the eucalyptus pulps. Also, the eucalypt pulps were much easier to beat than the pine pulps. The total fibre charge, as determined by conductometric titrations, was not affected by refining. However, the surface charge, as determined by titrations with poly-DADMAC, increased with refining. Increasing the specific surface area by refining resulted in a higher fibre surface charge and better fibre-fibre bonding. The change of the fibre surface charge during refining could be monitored using the FTIR characteristic bands within 1700-1300cm(-1).

Determination of carboxyl content in high-yield kraft pulps using photoacoustic rapid-scan Fourier transform infrared spectroscopy.

Pinus radiata kraft pulps with varying carboxyl content were studied using Fourier transform infrared photoacoustic spectroscopy (FT-IR-PAS). The examined pulp samples, with Kappa number ranging from 20.8 to 128, originated from pulping experiments conducted in flow-through reactors utilizing varying effective alkali, temperature, and cooking time. A partial least-squares (PLS) analysis was used to formulate a model that correlates the spectral data with the carboxyl content of pulp. Using three principal components, the resultant PLS model could explain approximately 98.5% of the variance in the X-matrix (spectral features) and 96.8% of the variance in the Y-matrix (measured carboxyl content). The FT-IR-PAS technique in combination with PLS analysis predicts the carboxyl content of the pulps with a high degree of accuracy. This method is much faster than the conventional titration methods and also not destructive to the pulp sample.

Isotherm sorption of Cd2+, Co2+, and Ni2+ onto high-yield kraft fibers.

The sorption capacity of high-yield kraft fibers for Cd2+, Co2+, and Ni2+ increased with pH and concentration of the cations in the liquid phase. Within the concentration range for the experiments, which was less than 2 mM, the experimental results fitted the Langmuir, Freundlich, and Sips models with regression coefficient greater than 0.97. Of the three cations investigated, Ni2+ had the highest sorption affinity, followed by Cd2+ and Co2+. The effect of the hydrated radius on the sorption affinity was discussed. Thermodynamically, the sorption was spontaneous and exothermic in the temperature range 283-308 K.

Competitive sorption of Na(+) and Ca(2+) ions on unbleached kraft fibres--a kinetics and equilibrium study.

In a binary system the sorption of Na(+) and Ca(2+) by kraft pulps follows a second order kinetics, and the isotherms follow the Langmuir model. The sorption capacity is dependent on pH and temperature. The thermodynamic parameters indicate that the sorption is exothermic and spontaneous. In a single-component system, the sorption capacity of the kraft pulp for Na(+) and Ca(2+) increases with the degree of dissociation of ionizable cellulosic components of the kraft pulp fibres. In a binary system the exchange of Na(+) and Ca(2+) is highly dependent on pH. SEM and X-ray analysis indicated that at pH above 11.0 calcium forms a precipitate bound to the surface of the fibres.

Sorption of Na+, Ca2+ ions from aqueous solution onto unbleached kraft fibers-kinetics and equilibrium studies.

The sorption of Na+ and Ca2+ from aqueous solutions onto unbleached kraft fiber was investigated. The sorption kinetics was found to be highly dependent on pH, initial concentration, and temperature. The sorption rate increased as the initial concentration and pH were increased. Thermodynamic and kinetic results indicated that the sorption of Na+ and Ca2+ onto kraft fiber was exothermic, reversible, and spontaneous with activation energies of 11.0 and 23.3 kJ/mol, respectively. The sorption kinetics followed a pseudo-second-order model and the equilibrium data followed the Langmuir isotherms. The fiber sorption capacities calculated from the Langmuir isotherms were similar to the fiber charges determined by potentiometric titration at pH > 7.

Extension of Donnan theory to predict calcium ion exchange on phenolic hydroxyl sites of unbleached kraft fibers.

The Donnan theory is extended to formulate a model for determination of the distribution coefficient of calcium in slurries of fully bleached and unbleached kraft fibers at different pH, taking into account the presence of both carboxylic and phenolic groups in the fibers. The intrinsic dissociation constants of the carboxylic acid groups and phenolic hydroxyl, which are the key inputs of the extended model, were determined by potentiometric titration. The extension improves the model prediction significantly, particularly when the presence of phenolic lignin in fibers becomes significant. However, when the pH exceeds 10, the model underestimates the distribution coefficient, suggesting that other factors may influence the fiber charge. The structural changes of the fiber wall at high pH and the presence of hydroxyl groups on the cellulose, which ionize at high pH, may be major factors.

Determination of fiber charge components of Lo-solids unbleached kraft pulps.

Four different titration methods for measurement of fiber charge were used in this study. Each method gave different fiber charge values depending on the acidity of the end point and the interaction between the fiber chemical components and the titrant. Also, the interactions between the ionizable groups on the fiber had significant effects on the interpretation of these results. The conductometric titrations showed trends similar to the results obtained from the potentiometric titration. The conductometric titrations with NaOH produced higher fiber charge values, higher than the titrations with NaHCO(3). The differences between the results obtained from the potentiometric and polyelectrolyte titrations, which were associated with the dissolved fiber components during the delignification, were linearly related to the Kappa number of pulps. The positive intercept of this linear relationship indicated that the kraft pulping process not only removed the ionizable groups associated with the dissolved components, but at the same time provided conditions to form new ionizable groups in the fibers. The polyelectrolyte titration results indicated that the lignin content in the fibers did not affect the fiber surface charge. Data extracted from the FTIR spectra of protonated fibers were highly correlated with the fiber charge values obtained from the conductometric titration with NaOH.

Feeding-induced changes in energy expenditure in children with cystic fibrosis.

Seven children with cystic fibrosis (aged 7 to 12 years) were studied in the fasted and fed states. Using a primed, constant, intravenous infusion of NaH13CO3, the rate of appearance of CO2 (RaCO2) was estimated. Net CO2 excretion (VCO2) was also measured. Energy expenditure was calculated using the food quotient. RaCO2 (mean +/- SD) (mumol.kg-1.min-1) in the fasted and fed states (297 +/- 59 and 359 +/- 67) was 117% and 105% of VCO2 (259 +/- 48 and 352 +/- 72). Feeding induced a 23% and a 37% increase in RaCO2 and VCO2, respectively, and respective 19% and 33% increases in energy expenditure (p < .05). Measurement of CO2 production by isotopic dilution is a useful index of group changes in energy expenditure, including those induced by feeding.

Protein quality and quantity in preterm infants receiving the same energy intake.

Fifteen low-birth-weight appropriate for gestational age infants, weighing 1.3 to 1.6 kg, were assigned to three isocaloric formulas differing in the quantity and form of nitrogen delivered. A balance study was done between 21 and 30 days after birth. Nitrogen retention expressed as milligram per kilogram per 100 kcal of metabolizable energy was greater with the 60:40 whey/casein and with the casein hydrolysate preparations than with the 20:80 whey/casein formula, which provided the same amount of energy (150 kcal/kg/day) but smaller quantities of protein (3.5 g/kg/day) than the two others (4.3 g/kg/day and 4.4 g/kg/day). Weight gain until discharge from the hospital and increment of height and head circumference over a three-month period showed an advantage of the two formulas providing higher intakes of protein. This study suggests that with high-energy intakes, protein quality does not affect nitrogen retention and growth unless the quantity of protein ingested falls below a critical level.

The composition of preterm milk in relation to the degree of prematurity.

Fifty-one samples of 24-h milk collections obtained during the 1st month of lactation from mothers who delivered after gestations of 26 to 31 wk (VPT) contained higher concentrations of nitrogen (297 +/- 11 mg/dl), total fatty acids (4.46 +/- 0.17 g/dl), percentage medium chain fatty acids (10.8 +/- 0.7), and energy (78.3 +/- 2.0 kcal/dl) than either or both those from 32 to 36 wk (PT) and term (T) gestations. PT collections did not differ from T milk with regard to nitrogen (250 +/- 13 versus 259 +/- 13), total fatty acids (3.94 +/- 0.20 versus 3.20 +/- 0.30), percentage medium chain fatty acids (9.1 +/- 0.5 versus 8.1 +/- 0.7) and energy (69.0 +/- 2.7 versus 66.6 +/- 2.4). Although postpartum age (5 to 10 versus 11 to 30 days) did not change the nutrient and energy content of VPT, PT, and T collections, it is only in 11 to 30 day VPT milk that nitrogen and energy content became higher (p less than 0.05) than either or both PT and T milk. We conclude that the differences in macronutrient composition of PT milk are limited to VPT milk and the data from repeated milk collections in the same mother (28 wk) suggest that there is considerable variability in its composition.