Climate and land-use changes interact to drive long-term reorganization of riverine fish communities globally.

As climate change unfolds, changes in population dynamics and species distribution ranges are expected to fundamentally reshuffle communities worldwide. Yet, a comprehensive understanding of the mechanisms and extent of community reorganization remains elusive. This is particularly true in riverine systems, which are simultaneously exposed to changing temperature and streamflow, and where land-use change continues to be a major driver of biodiversity loss. Here, we use the most comprehensive compilation of fish abundance time series to date to provide a global synthesis of climate- and LU-induced effects on riverine biota with respect to changes in species thermal and streamflow affinities. We demonstrate that fish communities are increasingly dominated by thermophilic (warm-water) and limnophilic (slow-water) species. Despite being consistent with trends in water temperature and streamflow observed over recent decades, these community changes appear largely decoupled from each other and show wide spatial variation. We further reveal a synergy among climate- and land use-related drivers, such that community thermophilization is heightened in more human-modified systems. Importantly, communities in which species experience thermal and flow regimes that approach or exceed their tolerance thresholds (high community sensitivity), as well as species-poor communities (low community resilience), also display faster rates of compositional change. This research illustrates that quantifying vulnerability of riverine systems to climate change requires a broadening from a narrower thermal focus to more integrative approaches that account for the spatially varying and multifaceted sensitivity of riverine organisms to the interactive effects of water temperature, hydrology, and other anthropogenic changes.

Transcoronary Gradients of Mechanosensitive MicroRNAs as Predictors of Collateral Development in Chronic Total Occlusion.

Background and Objectives: In this present study, we investigated the impact of mechanosensitive microRNAs (mechano-miRs) on the collateral development in 126 chronic total occlusion (CTO) patients, selected from 810 undergoing angiography. Materials and Methods: We quantified the collateral blood supply using the collateral flow index (CFI) and assessed the transcoronary mechano-miR gradients. Results: The patients with favorable collaterals had higher CFI values (0.45 ± 0.02) than those with poor collaterals (0.38 ± 0.03, p < 0.001). Significant differences in transcoronary gradients were found for miR-10a, miR-19a, miR-21, miR-23b, miR-26a, miR-92a, miR-126, miR-130a, miR-663, and let7d (p < 0.05). miR-26a and miR-21 showed strong positive correlations with the CFI (r = 0.715 and r = 0.663, respectively), while let7d and miR-663 were negatively correlated (r = -0.684 and r = -0.604, respectively). The correlations between cytokine gradients and mechano-miR gradients were also significant, including Transforming Growth Factor Beta with miR-126 (r = 0.673, p < 0.001) and Vascular Endothelial Growth Factor with miR-10a (r = 0.602, p = 0.002). A regression analysis highlighted the hemoglobin level, smoking, beta-blocker use, miR-26a, and miR-663 as significant CFI determinants, indicating their roles in modulating the collateral vessel development. Conclusions: These findings suggest mechanosensitive microRNAs as predictive biomarkers for collateral circulation, offering new therapeutic perspectives for CTO patients.

Effect of brimonidine on vascular density and imagej-derived flow index of optic nerve head and macula in primary open angle glaucoma.

PURPOSE: To study the effect of brimonidine on vascular density and flow index of optic nerve head (ONH) and macula in primary open angle glaucoma (POAG) using optical coherence tomography angiography (OCTA). METHODS: Twenty-three brimonidine-naïve POAG patients were started on brimonidine. They underwent OCTA ONH and macula before commencing brimonidine and one month thereafter. Systemic arterial blood pressure (SABP) and intraocular pressure (IOP) were measured at each visit to calculate mean ocular perfusion pressure (MOPP). The OCT angiograms were analyzed using ImageJ software to calculate ONH and macular flow indices. RESULTS: Thirty-seven eyes (23 patients) with a mean age of 56.7 ± 12.49 years were included of whom 60.8% were males. Brimonidine was associated with an increase in the superficial flow index (SFI) (P-value = 0.02) and optic nerve head flow index (ONHFI) (P-value = 0.01). Also, superficial vascular density (SVD) for whole image, superior-hemi and fovea increased (P-value = 0.03, 0.02, 0.03 respectively). ONH inferior-hemi vascular density decreased (P-value = 0.01) despite an increase in inferior quadrant retinal nerve fiber layer thickness (RNFLT) (P-value = 0.03). There was no statistically significant correlation between flow indices and MOPP at baseline and follow-up. A moderate negative correlation was found between SVD and DVD at the fovea and MOPP at baseline and follow-up (P-value = 0.03, 0.05) (P-value = 0.02, 0.01) respectively. CONCLUSIONS: Brimonidine was associated with an increase in SFI, ONHFI and SVD indicating improved GCC and RNFL perfusion in POAG. Despite the increase in inferior quadrant RNFLT, the concomitant decrease in inferior-hemi ONHVD precluded a conclusion of hemodynamically-mediated improvement of RNFLT.

Sublingual microcirculation and internal environment changes as early indications of sepsis: A prospective observational study.

OBJECTIVE: This study aims to investigate the changes in microcirculation and internal environment before sepsis in patients with infectious diseases. METHODS: In this single-center prospective observational study, all patients did not meet the diagnostic criteria of sepsis 3.0 at admission. Blood samples and sublingual microcirculation were collected at admission, 24 and 48 h after admission. RESULTS: A total of 101 patients completed this study. In total, 46 patients met the diagnostic criteria of sepsis 3.0 within 5 days after admission, while the remaining 55 patients did not. The platelet (PLT) was significantly lower in the sepsis patients (195.17 ± 63.89 vs. 242.02 ± 68.59, p = .01), Microvascular Flow Index (MFI) (2.45 ± 0.33 vs. 2.70 ± 0.18, p = .00) and Proportion of Perfused Vessels (PPV) (92.44 ± 4.45 vs. 95.88 ± 3.20, p = .00) were significantly lower, while Flow Heterogeneity Index (FHI) (0.32 ± 0.13 vs. 0.22 ± 0.10, p = .00) was significantly higher in the in the sepsis patients at admission. Decreased levels of MFI (p = .00, OR 0.02, 95% CI: 0.00, 0.15) and PLT (p = .00, OR 0.99, 95% CI: 0.98, 1.00) were independent risk factors for sepsis. Additionally, the 24 h PLT change rate (AUC 0.85, Cutoff -0.17, sensitivity 0.70, specificity 0.93, and Youden index 0.63) suggested a potential early warning effect for sepsis. CONCLUSION: Changes in microcirculation disturbance and the internal environment occurred before sepsis. The MFI and PLT are independent risk factors for sepsis. Sublingual microcirculation and PLT deterioration can be used as early warning indicators before sepsis.

Epinephrine iontophoresis attenuates changes in skin blood flow and abolishes cutaneous contamination of near-infrared diffuse correlation spectroscopy estimations of muscle perfusion.

Near-infrared diffuse correlation spectroscopy (NIR-DCS) is an optical imaging technique for measuring relative changes in skeletal muscle microvascular perfusion (i.e., fold change above baseline) during reactive hyperemia testing and exercise and is reported as a blood flow index (BFI). Although it is generally accepted that changes in BFI are primarily driven by changes in muscle perfusion, it is well known that large, hyperthermia-induced changes in cutaneous blood flow can uncouple this relationship. What remains unknown, is how much of an impact that changes in cutaneous perfusion have on NIR-DCS BFI and estimates of skeletal muscle perfusion under thermoneutral conditions, where changes in cutaneous blood flow are assumed to be relatively low. We therefore used epinephrine iontophoresis to pharmacologically block changes in cutaneous perfusion throughout a battery of experimental procedures. The data show that 1) epinephrine iontophoresis attenuates changes in cutaneous perfusion for up to 4-h posttreatment, even in the face of significant neural and local stimuli, 2) under thermoneutral conditions, cutaneous perfusion does not significantly impact NIR-DCS BFI during reactive hyperemia testing or moderate-intensity exercise, and 3) during passive whole body heat stress, when cutaneous vasodilation is pronounced, epinephrine iontophoresis preserves NIR-DCS measures of skeletal muscle BFI during moderate-intensity exercise. Collectively, these data suggest that cutaneous perfusion is unlikely to have a major impact on NIR-DCS estimates of skeletal muscle BFI under thermoneutral conditions, but that epinephrine iontophoresis can be used to abolish cutaneous contamination of the NIR-DCS BFI signal during studies where skin blood flow may be elevated but skeletal muscle perfusion is of specific interest.

Modification of the swirling well cell culture model to alter shear stress metrics.

Effects of hemodynamic shear stress on endothelial cells have been extensively investigated using the "swirling well" method, in which cells are cultured in dishes or multiwell plates placed on an orbital shaker. A wave rotates around the well, producing complex patterns of shear. The method allows chronic exposure to flow with high throughput at low cost but has two disadvantages: a number of shear stress characteristics change in a broadly similar way from the center to the edge of the well, and cells at one location in the well may release mediators into the medium that affect the behavior of cells at other locations, exposed to different shears. These properties make it challenging to correlate cell properties with shear. The present study investigated simple alterations to ameliorate these issues. Flows were obtained by numerical simulation. Increasing the volume of fluid in the well-altered dimensional but not dimensionless shear metrics. Adding a central cylinder to the base of the well-forced fluid to flow in a square toroidal channel and reduced multidirectionality. Conversely, suspending a cylinder above the base of the well made the flow highly multidirectional. Increasing viscosity in the latter model increased the magnitude of dimensional but not dimensionless metrics. Finally, tilting the well changed the patterns of different wall shear stress metrics in different ways. Collectively, these methods allow similar flows over most of the cells cultured and/or allow the separation of different shear metrics. A combination of the methods overcomes the limitations of the baseline model.

Validity of a novel optical coherence tomography angiography flow index in a cohort of primary open angle glaucoma.

BACKGROUND: Vascular mechanisms are implicated in many ocular diseases. Therefore, different vascular imaging modalities are used in management of such conditions. Optical coherence tomography angiography (OCTA) has high spatial resolution and segmentable 3D volumetric sampling enabling isolation of retinal and peripapillary vascular beds. However, OCTA only indirectly derives quantitative flow data i.e. velocimetry through methods and algorithms liable to limitations like signal saturation. This study introduces and validates novel mathematical OCTA flow indices that may compensate for some OCTA velocimetric limitations. METHODS: Thirty-seven eyes of 23 POAG patients were included. Each underwent baseline and follow-up assessment one month thereafter. Assessment comprised full ophthalmological examination, intraocular pressure (IOP), systemic arterial blood pressure (SABP) and OCTA macula and ONH. Angiograms were processed using ImageJ to calculate OCTA intensity-based flow indices (FIOs), for superficial vascular plexus (SVP), deep vascular plexus (DVP) and optic nerve head vascular plexus (ONH-RPC), i.e. SFIO, DFIO and ONHFIO respectively. Mean ocular perfusion pressure (MOPP) was calculated using IOP and SABP. OCTA vascular densities (VD) and MOPP were used to calculate three respective mathematical flow indices (FIMs) for SVP, DVP and ONH-RPC, based on Hagen-Poiseuille law, i.e. SFIM, DFIM, ONHFIM respectively. Pearson test was used for correlation between the two sets of indices. Intraclass correlation coefficient (ICC) was tested for baseline and follow-up values for each index. RESULTS: There was positive correlation between the three FIMs and their respective FIOs at baseline and follow-up ranging between high and moderate. Correlation coefficients (CCs) were 0.773 and 0.609 for SFIM and SFIO P-value < 0.001, 0.829 and 0.624 for DFIM and DFIO P-value < 0.001 and 0.516 and 0.737 for ONHFIM P-value = 0.001 for baseline and follow-up respectively. ICCs were 0.772 P-value < 0.001, 0.328 P-value = 0.022 and 0.888 P-value < 0.001 for SFIM, DFIM and ONHFIM respectively. For SFIO, DFIO and ONHFIO, ICCs were 0.420 P-value = 0.004, 0.079 P-value = 0.320 and 0.833 P-value < 0.001 respectively. CONCLUSION: The novel FIMs are reliable alternatives to FIOs and may compensate for OCTA signal saturation in extremes of MOPP. SFIM and ONHFIM showed high ICCs with excellent reliability. While DFIM demonstrated low ICC indicating poor reliability, it still performed better than its corresponding DFIO.

Do Cerebral Cortex Perfusion, Oxygen Delivery, and Oxygen Saturation Responses Measured by Near-Infrared Spectroscopy Differ Between Patients Who Fail or Succeed in a Spontaneous Breathing Trial? A Prospective Observational Study.

BACKGROUND: Alterations in perfusion to the brain during the transition from mechanical ventilation (MV) to a spontaneous breathing trial (SBT) remain poorly understood. The aim of the study was to determine whether changes in cerebral cortex perfusion, oxygen delivery (DO2), and oxygen saturation (%StiO2) during the transition from MV to an SBT differ between patients who succeed or fail an SBT. METHODS: This was a single-center prospective observational study conducted in a 16-bed medical intensive care unit of the University Hospital Leuven, Belgium. Measurements were performed in 24 patients receiving MV immediately before and at the end of a 30-min SBT. Blood flow index (BFI), DO2, and %StiO2 in the prefrontal cortex, scalene, rectus abdominis, and thenar muscle were simultaneously assessed by near-infrared spectroscopy using the tracer indocyanine green dye. Cardiac output, arterial blood gases, and systemic oxygenation were also recorded. RESULTS: During the SBT, prefrontal cortex BFI and DO2 responses did not differ between SBT-failure and SBT-success groups (p > 0.05). However, prefrontal cortex %StiO2 decreased in six of eight patients (75%) in the SBT-failure group (median [interquartile range 25-75%]: MV = 57.2% [49.1-61.7] vs. SBT = 51.0% [41.5-62.5]) compared to 3 of 16 patients (19%) in the SBT-success group (median [interquartile range 25-75%]: MV = 65.0% [58.6-68.5] vs. SBT = 65.1% [59.5-71.1]), resulting in a significant differential %StiO2 response between groups (p = 0.031). Similarly, a significant differential response in thenar muscle %StiO2 (p = 0.018) was observed between groups. A receiver operating characteristic analysis identified a decrease in prefrontal cortex %StiO2 > 1.6% during the SBT as an optimal cutoff, with a sensitivity of 94% and a specificity of 75% to predict SBT failure and an area under the curve of 0.79 (95% CI: 0.55-1.00). Cardiac output, systemic oxygenation, scalene, and rectus abdominis BFI, DO2, and %StiO2 responses did not differ between groups (p > 0.05); however, during the SBT, a significant positive association in prefrontal cortex BFI and partial pressure of arterial carbon dioxide was observed only in the SBT-success group (SBT success: Spearman's ρ = 0.728, p = 0.002 vs. SBT failure: ρ = 0.048, p = 0.934). CONCLUSIONS: This study demonstrated a reduced differential response in prefrontal cortex %StiO2 in the SBT-failure group compared with the SBT-success group possibly due to the insufficient increase in prefrontal cortex perfusion in SBT-failure patients. A > 1.6% drop in prefrontal cortex %StiO2 during SBT was sensitive in predicting SBT failure. Further research is needed to validate these findings in a larger population and to evaluate whether cerebral cortex %StiO2 measurements by near-infrared spectroscopy can assist in the decision-making process on liberation from MV.

Sublingual microcirculation: comparison between the 415 nm blue light and 520 nm green light of sidestream dark field videomicroscopes.

Green light with a wavelength of 520 nm is commonly used in sidestream dark field (SDF) video microscopes for sublingual microcirculation assessment in clinical practice. However, blue light could obtain a clearer microcirculatory image due to a higher light absorption coefficient of hemoglobin. The aim of this study was to compare the sublingual microcirculatory image quality acquisition and related microcirculatory parameters between 520 nm green light and 415 nm blue light probes in the SDF device named MicroSee V100. Sublingual microcirculation films from twenty-one healthy volunteers were prospectively collected by blue light and green light probes, and only one video of each wavelength was recorded and analyzed in each volunteer. Moreover, 200 sublingual microcirculation films (100 by blue light probe and 100 by green light probe) of ICU patients were retrospectively scored for microcirculation image quality. Compared to green light, an increase in the perfused vessel density (paired t test, increased by 4.6 ± 4.7 mm/mm2, P < 0.0001) and total vessel density (paired t test, increased by 5.1 ± 4.6 mm/mm2, P < 0.0001) was observed by blue light in the healthy volunteers. The blue light probe had a significantly lower rate of unacceptable films than the green light probe in the 200 films of ICU patients (10/100 vs. 39/100, P < 0.0001). Blue light provides a higher microcirculatory vessel density and image quality than the existing SDF probe using green light.

Coronary Collateral Flow Index Is Correlated With the Palmar Collateral Flow Index: Indicating Systemic Collateral Coherence in Individual Patients-Brief Report.

[Figure: see text].

Evaluation of placental growth potential and placental bed perfusion by 3D ultrasound for early second-trimester prediction of preeclampsia.

PURPOSE: This study aimed to investigate whether placental parameters measured by three-dimensional ultrasound are associated with preeclampsia (PE) and small-for-gestational-age (SGA). METHODS: In total, 1163 pregnancies at 11-14 weeks of gestation were recruited between October 8, 2020, and April 30, 2021. Placenta volume (PV), placental bed vascularization flow index (PBVFI), and uterine arteries pulse index (UtA-PI) were measured. Placental quotient (PQ = PV/weeks of gestation) was calculated. All participants were re-examined 4 weeks later. The placental volume growth rate (PVGR = placental volume difference between the two examinations/interval days) was also calculated. Patients were divided into four groups by the gestational age at the onset of PE and birth weight: early-onset PE (E-PE, n = 18), late-onset PE (L-PE, n = 36), isolated SGA5 (birth weight less than the fifth percentile for gestational age without PE, n = 9), and unaffected (n = 1100) groups. RESULTS: A predictive model for E-PE was established, which consisted of unnatural conception, chronic hypertension, PBVFI (of second examination), and PVGR for E-PE; 94.4% sensitivity and 96.7% specificity by receiver operating characteristic curve analysis. CONCLUSIONS: Overall, decreased placental growth potential and low placental bed perfusion in the early second trimester have potential in predicting E-PE.

Effect of pulsed electromagnetic fields stimulation on ischemic skin model.

This study aimed to evaluate the effect of Pulsed Electromagnetic Fields (PEMF) in improving blood flow reduction and tissue necrosis of ischemic animal induced by skin flap. In each experiment, twenty rats (280-320 g) were randomly divided into control group (n = 10) and PEMF (n = 10) group. All of the rats were performed skin flap in back. In the PEMF group, PEMF (1 Hz, 10 mT) was performed in each experiment. In Experiment-1 (n = 20), PEMF was performed for 90 minutes. In Experiment-2 (n = 20), additionally, a blocking film was inserted, and suture was performed to induce necrosis. PEMF was performed for 30 minutes each day for 7 days. As a result of Speckle-Flow Index (SFI) analysis, in the control group, blood flow continued to decrease immediately after the procedure. In the PEMF group, blood flow was remained constant after 30 minutes and increased after 60 minutes. The blood flow in a specific region substantially increased from the initial state. As a result of skin necrosis analysis, the progression rate in the PEMF group was slower than that of the control group. The rate of necrosis in the PEMF group decreased dramatically from the 6th day, and there was a statistically significant difference between the two groups at the 7th day (p < .05). In this study, it was confirmed that PEMF (1 Hz, 10 mT) has a blood flow improvement and skin tissue necrosis alleviation in the ischemic flap animal model.

Starch flow behavior alone and under different glidants action using the shear cell method.

The objective of this work was to analyze the flow behavior of a commonly used filler (pregelatinised starch) and the effect of two of the most used lubricants (talc and colloidal silicon dioxide). The studies were carried out according to the conventional methods (Angle of Repose, Bulk and Tapped densities and from these the Compressibility Index) and shear cell methods (Brookfield Powder Flow Tester apparatus) described in European Pharmacopeia (Ph. Eur.). The results showed some surprising and unexpected values for the flow behavior of this filler under influence of the methods and the used glidants. Regarding pure starch and mixtures containing talc, the flow behavior was similar between them and the Flow Index (ffc) values varied between 1.8 and 4 (very cohesive and cohesive) as consolidation stress (σ1) increased. In this case, the glidant effect was not observed. However, for the mixtures of starch with colloidal silicon dioxide this effect was observed providing Flow Index (ffc) values between 2.6 and 8.9 (cohesive and easy-flowing) as consolidation stress (σ1) increased. Other parameters that are also used to characterize flow properties, more specifically, within silos, chutes and hoppers, such as effective angle of internal friction (φe), effective angle of wall friction (φx), critical arching and critical rathole values, provided similar information. Based in the obtained results from all tests it can be said that the talc did not induce improvement on the starch flow behavior in the used conditions in opposition to the effect produced by colloidal silicon dioxide.HighlightsExample 1. A good flowability of powders is needed in order to be compressed/filled;Example 2. The overcome the poor flow it is usual to use glidants;Example 3. CSD improved the pregelatinised starch (Starch 1500®) flow;Example 4. Talc do not have relevant effect in the pregelatinised starch (Starch 1500®) flow;Example 5. Powder FlowTester method showed more complete and consistent results.

Near-infrared spectroscopy measures of sternocleidomastoid blood flow during exercise and hyperpnoea.

NEW FINDINGS: What is the central question of this study? How does sternocleidomastoid blood flow change in response to increasing ventilation and whole-body exercise intensity? What is the main finding and its importance? Sternocleidomastoid blood flow increased with increasing ventilation. For a given ventilation, sternocleidomastoid blood flow was lower during whole-body exercise compared to resting hyperpnoea. These findings suggest that locomotor muscle work exerts an effect on respiratory muscle blood flow that can be observed in the sternocleidomastoid. ABSTRACT: Respiratory muscle work influences the distribution of blood flow during exercise. Most studies have focused on blood flow to the locomotor musculature rather than the respiratory muscles, owing to the complex anatomical arrangement of respiratory muscles. The purpose of this study was to examine how accessory respiratory (i.e. sternocleidomastoid, and muscles in the intercostal space) muscle blood flow changes in response to locomotor muscle work. Seven men performed 5 min bouts of constant load cycling exercise trials at 30%, 60% and 90% of peak work rate in a randomized order, followed by 5 min bouts of voluntary hyperpnoea (VH) matching the ventilation achieved during each exercise (EX) trial. Blood-flow index (BFI) of the vastus lateralis, sternocleidomastoid (SCM) and seventh intercostal space (IC) were estimated using near-infrared spectroscopy and indocyanine green and expressed relative to resting levels. BFISCM was greater during VH compared to EX (P = 0.002) and increased with increasing exercise intensity (P = 0.036). BFISCM reached 493 ± 219% and 301 ± 215% rest during VH and EX at 90% peak work rate, respectively. BFIIC increased to 242 ± 178% and 210 ± 117% rest at 30% peak work rate during VH and EX, respectively. No statistically significant differences in BFIIC were observed with increased work rate during VH or EX (both P > 0.05). Moreover, there was no observed difference in BFIIC between conditions (P > 0.05). BFISCM was lower for a given minute ventilation during EX compared to VH, suggesting that accessory respiratory muscle blood flow is influenced by whole-body exercise.

The relationship among flow index, uroflowmetry curve shape, and EMG lag time in children.

PURPOSE: To determine the relationship among flow index (FI), uroflowmetry curve shape, and electromyography (EMG) lag time in children. MATERIALS AND METHODS: A total of 294 children with lower urinary tract symptoms were included. The overall relationship between lag time and FI was investigated with curve estimation regression. Normal and primary bladder neck dysfunction was defined according to the previous classification, while patients with a lag time less than 2 seconds were grouped based on 2-second intervals. We also categorized cases into four groups (tower shaped, bell shaped, plateau shaped, and fractionated void) by FI and compared lag time. RESULTS: The overall distribution chart demonstrated that FI was the highest at lag time 0 second and decreased with the change in lag time both ways. The best fitting model for maximum FI and lag time was a cubic model (R2 = .282; P < .001). Children with lag times from 0 to less than 2 seconds showed the highest mean FI, while those with prolonged (>6 seconds) or delayed lag time (<-4 seconds) demonstrated lower mean FI values. EMG lag time of the tower-shaped curve was significantly close to 0 second, and plateau shaped and fractionated void had either prolonged or delayed. CONCLUSIONS: A lag time close to 0 second was associated with higher FI, representing hyperefficient voiding with a tower-shaped flow pattern. However, children with prolonged or delayed lag time showed a lower FI, implicating hypoefficient voiding and a plateau-shaped flow pattern. The relationship between FI and EMG lag time could be a cornerstone for a comprehensive understanding of voiding status.

Monitoring of the Sublingual Microcirculation During Cardiac Surgery: Current Knowledge and Future Directions.

Handheld vital microscopes allow for direct observation of the sublingual microcirculatory perfusion during cardiac surgery. Through the use of handheld vital microscopes, it has been shown that cardiac surgery with cardiopulmonary bypass is associated with reduced and heterogenous microcirculatory perfusion. Microcirculatory impairment can result in inadequate tissue perfusion, leading to perioperative complications and poor outcome. Because microcirculatory impairment can occur despite stable or improved global hemodynamics, there is a yet unmet need for specific monitoring of the microcirculation. Technological advancements may facilitate point-of-care monitoring of microcirculatory perfusion using automated real-time analysis of microcirculatory measurements. Thus, microcirculatory monitoring may create new opportunities for specific microcirculatory treatment as part of hemodynamic management. The implementation of microcirculatory variables into personalized treatment concepts has the potential to improve hemodynamic management during cardiac surgery and thereby improve patient outcomes. Therefore, specific treatment strategies need to be developed to prevent or treat alterations of the microcirculatory perfusion. In the future, the use of handheld vital microscopes for microcirculatory monitoring may help to improve hemodynamic management and outcomes for patients undergoing cardiac surgical procedures.

Biot-Granier Sensor: A Novel Strategy to Measuring Sap Flow in Trees.

The Biot-Granier (Gbt) is a new thermal dissipation-based sap flow measurement methodology, comprising sensors, data management and automatic data processing. It relies on the conventional Granier (Gcv) methodology upgraded with a modified Granier sensor set, as well as on an algorithm to measure the absolute temperatures in the two observation points and perform the Biot number approach. The work described herein addresses the construction details of the Gbt sensors and the characterization of the overall performance of the Gbt method after comparison with a commercial sap flow sensor and independent data (i.e., volumetric water content, vapor pressure deficit and eddy covariance technique). Its performance was evaluated in three trials: potted olive trees in a greenhouse and two vineyards. The trial with olive trees in a greenhouse showed that the transpiration measures provided by the Gbt sensors showed better agreement with the gravimetric approach, compared to those provided by the Gcv sensors. These tended to overestimate sap flow rates as much as 4 times, while Gbt sensors overestimated gravimetric values 1.5 times. The adjustments based on the Biot equations obtained with Gbt sensors contribute to reduce the overestimates yielded by the conventional approach. On the other hand, the heating capacity of the Gbt sensor provided a minimum of around 7 °C and maximum about 9 °C, contrasting with a minimum around 6 °C and a maximum of 12 °C given by the Gcv sensors. The positioning of the temperature sensor on the tip of the sap flow needle proposed in the Gbt sensors, closer to the sap measurement spot, allow to capture sap induced temperature variations more accurately. This explains the higher resolution and sensitivity of the Gbt sensor. Overall, the alternative Biot approach showed a significant improvement in sap flow estimations, contributing to adjust the Granier sap flow index, a vulnerability of that methodology.

Lactose monohydrate flow characterization using shear cell method.

The flow properties of pharmaceutical powders have a great importance in the manufacturing of solid dosage forms. In order to ensure the performance in the production line this parameter must be determined. There are several methods described in European Pharmacopeia that are used to measure these properties. Some of them were used in this study and the results obtained from conventional methods (Conv) and shear cell using the powder flow tester (PFT) showed differences that were more evident in fractions with smaller particle size (F < 63) and for bulk powder (FTotal). The various powder behaviors showed to be related with the size of the particles. An increase of the ffc (Flow Index) was observed with the increase of the particle size. It was also found for the different fractions that the ffc always increases with increasing major principal consolidation stress (σ1). This study shown to be predictive because it also allowed the behavior profiles of other LactMN fractions to be known by interpolation of the median size (Dv50) or σ1 values ranged between the studied intervals. Furthermore, it was also observed that ffc of the FTotal was similar to the F < 63, showing the same behavior under σ1. The occurrence of caking was not observed.

Flow characterization of a pharmaceutical excipient using the shear cell method.

The powders used in the production of solid dosage forms must have ability to flow that allows their industrial processing. Although this property has been studied for most of the powders, in this study non-expected flow behaviors were observed for the model excipient used, Microcrystalline Cellulose (MCC). Several fractions with different sizes were fractioned by sieving of the model excipient and its flow behaviors were analyzed by different methods. The shear cell results showed an increase of the flowability index (ffc) with the increase of the particle size and consolidation stress. Some related information has been referenced in the literature, however, in this work it was shown for different size fractions that the ffc decreased above a certain consolidation stress value (2000-4000 N/m2). The explanation of this phenomenon is based on the increase of cohesion. Furthermore, it was also observed that the fractions with sizes between 125-180 µm present a ffc higher than bulk powder (FTotal) with similar percentile (DV50) indicating that this index is dependent on the size of the particles and also on its size distribution range. Thus, it can be affirmed that more homogeneous samples in size and with a narrower distribution present a better ffc.

Comparison of Four Haemodynamic Tests that Quantify Superficial Venous Insufficiency.

OBJECTIVES: Reflux assessment with ultrasound (U/S) is usually qualitative. Quantitative measurements of superficial venous insufficiency (SVI) include the venous arterial flow index (VAFI), recirculation index (RCI), venous filling index (VFI), and the postural diameter change (PDC) of the saphenous trunk. The aim was to investigate their relationship. MATERIALS AND METHODS: This was an observational study performed on patients with varicose veins and hospital employees. Four haemodynamic parameters were measured in 21 legs from 16 subjects. Legs were divided into no reflux (n = 7) and reflux (n = 14). The VAFI is the U/S ratio of common femoral vein volume flow divided by the common femoral artery volume flow, performed supine. The RCI is the U/S ratio of reflux volume over antegrade volume within the saphenous trunk after calf compression, standing. The VFI is the rate of calf volume increase on dependency measured in mL/s, using air plethysmography. The PDC is the percentage reduction of the saphenous trunk diameter from standing to lying, using U/S. RESULTS: The clinical part of the CEAP classification was: C0 = 3, C1 = 4, C2 = 5, C3 = 1, C4a = 1, C4b = 6, C5 = 1. All four tests demonstrated significant differences between the two groups with minimal overlap (Mann Whitney U test): VAFI (p = .028), RCI (p < .0005), VFI (p = .001), and PDC (p = .014). Furthermore, significant correlations were observed with the tests: VAFI vs. RCI (r = .532, p = .015), VFI (r = .489, p = .025) and PDC (r = -.474, p = .030); RCI vs. VFI (r = .446, p = .043) and PDC (r = -.527, p = .014). CONCLUSIONS: Superficial venous drainage insufficiency should not be confined to an U/S assessment of the presence of reflux, which is qualitative. Quantitative data may be provided using the VAFI, RCI, VFI, and PDC. Understanding why there are significant correlations among these parameters and the preferred objective reference test requires further work.