Ratios R1 Research Articles

Organic Matter Composition and Water Stoichiometry Are Main Drivers of Heterotrophic Nitrate Uptake in Mediterranean Headwater Streams

AbstractHeterotrophic bacteria can contribute to improve stream water quality by taking up nitrate (NO3−) from the water column, although microbial demand for this nutrient is usually lower than for other inorganic nitrogen (N) forms, such as ammonium. Heterotrophic NO3− uptake has been related to the availability of dissolved organic carbon (DOC) relative to nutrients (i.e., DOC: nutrients ratios). Yet, how dissolved organic matter (DOM) composition and specific microbial assemblages influence NO3− uptake remains poorly understood. We conducted laboratory incubations to investigate heterotrophic NO3− uptake kinetics in 9 Mediterranean freshwater ecosystems, primarily headwater streams, exhibiting wide variation in DOC:NO3 ratios (from 1.5 to 750). Moreover, we characterized DOM composition using spectroscopic indexes and its degradation via a reactivity continuum model approach. Microbial community composition and functioning were assessed by analyzing extracellular enzymatic activities and the potential abundance of N‐cycling genes. Our results revealed that NO3− uptake rates (kNO3) were positively related with DOC:NO3 ratios (r2 = 0.4) and to NO3:SRP ratios as well (r2 = 0.6). Furthermore, kNO3 was negatively correlated to the humification index (r2 = 0.7), suggesting that a higher proportion of humic‐like compounds slow down heterotrophic NO3− uptake. A partial least squares regression model (PLS) pinpointed that DOC and nutrient stoichiometry, DOM composition and reactivity, and microbial composition and activity collectively contributed to explain the variability in kNO3 observed across treatments. Our findings suggest that heterotrophic NO3− uptake may show significant responsiveness to shifts toward more labile DOM sources and nutrient imbalances induced by global change.

Synthesis of Antimicrobial and Antioxidant Zinc Oxide Hydrogel for Drug Delivery Applications

A novel and simple method was used to synthesize antimicrobial and antioxidant porous (N-tert-butylacrylamide-co-N-vinylpyrrolidone) zinc oxide hydrogel via free radical copolymerization. The hydrogel was characterized by NMR, XRD, and SEM. Thermodynamic properties of the hydrogel were described quantitatively by the Flory-Rehner method. The results indicate that the synthesized hydrogel exhibits strong antioxidant activity, making it a potential candidate for use in preventing degenerative diseases. The antimicrobial tests showed that the hydrogel could inhibit the growth of Gram-positive and Gram-negative bacteria, as well as some pathogenic bacteria and fungi. The inhibition zones ranged from 10 to 15 mm for bacteria and from 5.2 to 9.1 mm for fungi. The reactivity ratio r1 × r2 equal to 1 confirmed ideal copolymerization showed the composition of the copolymer and the comonomer feed are same. The hydrogel's structure and reactivity are significant for constructing effective delivery systems for specific applications. Optimizing the monomer proportion could enhance hydrogel efficiency and release behavior. The hydrogel's water solubility, non-toxicity, and antioxidant properties suggest it could be safe and effective throughout the drug delivery process, contributing both passive and reactive targeting functions.

Quantification of respiratory sinus arrhythmia in control dogs and in dogs with various severity classes of myxomatous mitral valve disease

IntroductionLoss of respiratory sinus arrhythmia (RSA) is a negative prognostic factor in dogs with myxomatous mitral valve disease (MMVD). The aim of this study was to calculate the percentage (%) of RSA in healthy dogs and dogs in various MMVD classes. AnimalsControl and MMVD dogs were prospectively included in the study. Materials and methodsRespiratory sinus arrhythmia was calculated from a dual channel electrocardiography and breathing curve recording using the peak-to-trough method, in percent of the average heart rate. ResultsOne hundred and forty-nine dogs were studied, including 24 control and 125 MMVD dogs of different severity classes. An overall %RSA decrease was documented with increasing disease severity up to the Ca class along with a relative %RSA increase in the Cc class. The %RSA magnitude differed between B2 and Ca (P<0.001), and between Ca and Cc (P = 0.001) groups, respectively. The %RSA showed a medium negative correlation with the La:Ao ratio (r2 = −0.568, P<0.001) and with the E-wave velocity (r2 = −0.561, P<0.001). DiscussionsA decrease in %RSA was shown with increased disease severity up to acute congestive heart failure (CHF). Dogs receiving cardiac therapy leading to stabilized CHF might restore their ability to exhibit RSA, often revealing a higher %RSA compared to those in acute CHF. Study limitationsLow number of respiratory cycles for analysis. Therapy effect not evaluated. ConclusionsThe findings of this study can serve as the basis for future risk stratification and carry the potential of proving an additional clinical marker for diagnostic and therapeutic decisions making when managing MMVD dogs.

Correlation between worsening pneumonitis and right ventricular systolic function in critically ill patients with COVID-19

BackgroundThe pneumonitis associated with coronavirus disease 2019 (COVID-19) infection impacts the right ventricle (RV). However, the association between the disease severity and right ventricular systolic function needs elucidation.MethodWe conducted a retrospective study of 108 patients admitted to critical care with COVID-19 pneumonitis to examine the association between tricuspid annular plane systolic excursion (TAPSE) by transthoracic echocardiography as a surrogate for RV systolic function with PaO2/FiO2 ratio as a marker of disease severity and other respiratory parameters.ResultsThe median age was 59 years [51, 66], 33 (31%) were female, and 63 (58%) were mechanically ventilated. Echocardiography was performed at a median of 3 days [2, 12] following admission to critical care. The PaO2/FiO2 and TAPSE medians were 20.5 [14.4, 32.0] and 21 mm [18, 24]. There was a statistically significant, albeit weak, association between the increase in TAPSE and the worsening of the PaO2/FiO2 ratio (r2 = 0.041, p = 0.04). This association was more pronounced in the mechanically ventilated (r2 = 0.09, p = 0.02). TAPSE did not correlate significantly with FiO2, PaO2, PaCO2, pH, respiratory rate, or mechanical ventilation. Patients with a TAPSE ≥ 17 mm had a considerably worse PaO2/FiO2 ratio than a TAPSE < 17 mm (18.6 vs. 32.1, p = 0.005). The PaO2/FiO2 ratio predicted TAPSE (OR = 0.94, p = 0.004) with good area under the curve (0.72, p = 0.006). Moreover, a PaO2/FiO2 ratio < 26.7 (moderate pneumonitis) predicted TAPSE > 17 mm with reasonable sensitivity (67%) and specificity (68%).ConclusionIn patients admitted to critical care with COVID-19 pneumonitis, TAPSE increased as the disease severity worsened early in the course of the disease, especially in the mechanically ventilated. A TAPSE within the normal range is not necessarily reassuring in early COVID-19 pneumonitis.

Left ventricular dysfunction in pulmonary arterial hypertension is attributed to underfilling rather than intrinsic myocardial disease: a CMR 2D phase contrast study

The pathophysiology underlying impaired LV function in PAH remains unclear, with some studies implicating intrinsic myocardial dysfunction and others pointing to LV underfilling. Evaluation of pulmonary vein area (PVA) and flow may offer novel, mechanistic insight by distinguishing elevated LV filling pressure common in myocardial dysfunction from LV underfilling. This study aimed to elucidate LV filling physiology in PAH by assessing PVA and flow using cardiac magnetic resonance (CMR) and compare pulmonary vein flow in PAH with HFrEF as a model representing elevated filling pressures, in addition to healthy controls. Patients with PAH or heart failure with reduced ejection fraction (HFrEF) referred for CMR were retrospectively reviewed, and healthy controls were included as reference. Pulmonary vein S, D and A-wave were compared between groups. Associations between pulmonary vein area (PVA) by CMR and echocardiographic indices of LV filling pressure were evaluated. Nineteen patients with PAH, 25 with HFrEF and 24 controls were included. Both PAH and HFrEF had lower ejection fraction and S-wave velocity than controls. PAH displayed smaller LV end-diastolic volumes than controls, while HFrEF demonstrated larger PVA and higher A-wave reversal. PVA was associated with mitral E/e′ ratio (r2 = 0.10; p = 0.03), e′ velocity (r2 = 0.23; p = 0.001) and left atrial volume (r2 = 0.07; p = 0.005). Among PAH, PVA was not associated with LV-GLS. A PVA cut-off of 2.3cm2 displayed 87% sensitivity and 72% specificity to differentiate HFrEF and PAH (AUC = 0.82). PAH displayed lower pulmonary vein S-wave velocity, smaller LV volume and reduced function compared with controls. Reduced LV function in PAH may be owing to underfilling rather than intrinsic myocardial disease. PVA demonstrates promise as a novel, non-invasive imaging marker to assess LV filling status.

Novel cross section ratios as possible signals of saturation in ultraperipheral collisions

We propose new cross section ratios in ultraperipheral A+A and p+A collisions (UPCs) as a potential experimental signal of saturation physics. We consider the ratio R1 of elastic vector meson photoproduction cross section to the inclusive hadron or jet photoproduction cross section. The ratio can be measured in the γ+A and γ+p collisions taking place in the UPCs. We label the ratios R1(A) and R1(p), respectively. Constructing the double ratio RUPC(A)=R1(A)/R1(p), and performing a small-x calculation both in the quasiclassical approximation and by including small-x evolution, we observe that RUPC(A) exhibits a markedly different dependence on the nuclear atomic number inside and outside the saturation region. This result indicates that RUPC(A) and R1(A) measurements in UPCs may help in the experimental searches for the evidence of saturation physics. Published by the American Physical Society 2024

The global distribution of Isoprenoidal Glycerol Dialkyl Diethers (isoGDDs) is consistent with a predominant degradation origin

Glycerol dialkyl diethers (GDDs) are membrane lipids and a variation of the more commonly known glycerol dialkyl glycerol tetraethers (GDGTs). GDGTs include both archaeal and bacterial membrane lipids that are both frequently used for paleoclimate reconstruction in a range of terrestrial and aquatic environments. In contrast to GDGTs, GDDs lack one of the terminal glycerol moieties. Although both isoprenoidal (iso) and branched (br) GDDs have been found, this study focuses on isoGDDs. These lipids have been found in a few terrestrial and aquatic environments. However, the origin of isoGDDs is debated and the extent of their distribution across the surface of the Earth is poorly constrained. Based on a few single site studies, previous authors hypothesised that isoGDDs are degradation products of isoGDGTs, but more recent studies that isolated isoGDDs from cultured nitrososphaerota (formerly thaumarchaeota) proposed a biological source through direct archaeal biosynthesis. Here we compiled a global dataset of isoGDD and isoGDGT abundance in environmental samples to thoroughly investigate the distribution of isoGDDs and the correlation with isoGDGTs on a global scale and across a variety of environments (peat, mineral soils, lake sediments, and marine sediments). We find that isoGDDs are present in most samples that we analysed. Their abundance is strongly proportional to isoGDGT abundance (r2 = 0.85), dominated by the GDGT-crenarchaeol/GDD-crenarchaeol ratio (r2 = 0.94) and supported by individual compound isoGDGT/isoGDD ratios (r2 = 0.56–0.94). In addition, the degree of cyclisation of isoGDDs, reflected in the ring index, is positively correlated (r2 = 0.84) with that of isoGDGTs across all environments. We conclude that isoGDDs are abundant on the surface of the Earth and predominantly originate from the degradation of isoGDGTs.

The double-peaked type I X-ray bursts with different mass accretion rate and fuel composition

ABSTRACT Using the mesa (Modules for Experiments in Stellar Astrophysics) code, we have carried out a detailed survey of the available parameter space for the double-peaked type I X-ray bursts. We find that the double-peaked structure appears at mass accretion rate $\dot{M}$ in the range of $\sim (4-8)\times 10^{-10}\, {\rm M}_{\odot }\,{\rm yr}^{-1}$ when metallicity Z = 0.01, while in the range of $\sim (4-8)\times 10^{-9}\, {\rm M}_{\odot }\,\rm {yr}^{-1}$ when Z = 0.05. Calculations of the metallicity impact suggest that the double peaks will disappear when Z ≲ 0.005 for $\dot{M}=5\times 10^{-10}\, {\rm M}_{\odot }\,\rm {yr}^{-1}$ and Z ≲ 0.04 for $\dot{M}=5\times 10^{-9}\, {\rm M}_{\odot }\,\rm {yr}^{-1}$. Besides, the impacts of base heating Qb, as well as nuclear reaction waiting points: $^{22}\rm {Mg}$, $^{26}\rm {Si}$, $^{30}\rm {S}$, $^{34}\rm {Ar}$, 56Ni, $^{60}\rm Zn$, $^{64}\rm {Ge}$, $^{68}\rm {Se}$, and $^{72}\rm {Kr}$ have been explored. The luminosity of the two peaks decreases as Qb increases. 68Se(p, γ)69Br is the most sensitive reaction, the double peaks disappear assuming that 56Ni(p, γ)57Cu, and 64Ge(p, γ)65As reaction rates have been underestimated by a factor of 100 and the 22Mg(α, p)25Al reaction rate has been overestimated by a factor of 100, which indicates that 22Mg, 56Ni, 64Ge, and 68Se are possibly the most important nuclear waiting points impedance in the thermonuclear reaction flow to explain the double-peaked bursts. Comparisons to the double-peaked bursts from 4U 1636−53 and 4U 1730−22 suggest that the nuclear origins of double-peaked type I X-ray bursts are difficult to explain the observed larger peak times ($t_{\rm p,1}\gtrsim 4\, {\rm s}$, $t_{\rm p,2}\gtrsim 8\, {\rm s}$) and smaller peak ratio (r1, 2 ≲ 0.5). The composition of ashes from double-peaked bursts is very different from the single-peaked bursts especially for the heavier p-nuclei.

Relationships between Dietary Chemical Components and Enteric Methane Production and Application to Diet Formulation in Beef Cattle

We used published data consisting of 263 treatment mean observations from beef cattle and dairy steers and heifers, in which CH4 was measured via chambers or head boxes, to evaluate relationships between enteric CH4 production and dry matter intake (DMI) and dietary components. Daily DMI was positively related (slope = 15.371, p &lt; 0.001) to total daily production (g/d) of CH4 (r2 = 0.821). Among chemical components, dietary neutral detergent fiber (NDF) concentration was the most highly related (r2 = 0.696; slope = 0.2001; p &lt; 0.001) to CH4 yield (g/kg of DMI), with strong relationships also noted for dietary starch:NDF ratio (r2 = 0.662; slope = −2.4587; p &lt; 0.001), starch (r2 = 0.495; slope = −0.106; p &lt; 0.001), and the proportion of metabolizable energy relative to gross energy (r2 = 0.561; slope = −23.663; p &lt; 0.001). The slope (−0.5871) and intercept (22.2295) for the dietary ether extract vs. CH4 yield were significant (p &lt; 0.001), but the relationship was highly variable (r2 = 0.150). For dietary crude protein concentration, the slope for CH4 yield was not significant (−0.0344; p &lt; 0.381) with an r2 value near zero. Decreasing DMI by programming body weight gain or restricting feed intake could decrease CH4 production in confined cattle, but these approaches might negatively affect growth performance and product quality, potentially negating positive effects on CH4 production. Feeding higher-quality forages or using grazing management systems that decrease dietary NDF concentrations or substituting grain (starch) for forage should decrease both CH4 yield from enteric production and manure CH4 production via increased digestibility. Effects of feeding management and diet formulation strategies should be additive with other mitigation approaches such as feed additives, allowing the cattle industry to achieve maximal decreases in enteric CH4 production, while concurrently maintaining optimal beef production.

Cross-shelf processes of terrigenous organic matter drive mercury speciation on the east siberian shelf in the Arctic Ocean

The cross-shelf distributions of total mercury (THg), methylmercury (MeHg) and organic and inorganic matter, as well as the presence of the hgcA gene were investigated on the East Siberian Shelf (ESS) to understand the processes underlying the speciation of sedimentary Hg. Samples were collected from 12 stations grouped into four zones based on water depth: inner shelf (5 stations), mid-shelf (3 stations), outer shelf (2 stations), and slope (2 stations). The THg concentration in the surface sediment increased from the inner shelf (0.25 ± 0.023 nmol g−1) toward the slope (0.52 nmol g−1), and, when normalized to total organic carbon content, the THg showed a positive correlation with the clay-to-sand ratio (r2 = 0.48, p = 0.012) and degree of chemical weathering (r2 = 0.79, p = 0.0001). The highest MeHg concentrations (3.0 ± 1.8 pmol g−1), as well as peaks in the S/C ratio (0.012 ± 0.002) of sediment-leached organic matter, were found on the mid-shelf, suggesting that the activities of sulfate reducers control the net Hg(II) methylation rates in the sediment. This was supported by results from a principal component analysis (PCA) performed with Hg species concentrations and sediment-leached organic matter compositions. The site-specific variation in MeHg showed the highest similarity with that of CHONS compounds in the PCA, where Deltaproteobacteria were projected to be putative Hg(II) methylators in the gene analysis. In summary, the hydrodynamic sorting of lithogenic particles appears to govern the cross-shelf distribution of THg, and in situ methylation is considered a major source of MeHg in the ESS sediment.

Impacts of human and herbivorous feces on lake surface sediments of the Tibetan Plateau based on fecal stanol proxies

Lake ecosystems on the Tibetan Plateau (TP) are highly susceptible to external input owing to their fragile environment. However, less study has been done to focus the direct influences of anthropogenic activities on the lake sediments by human activities. In this study, we performed the first large-scale investigation to use the fecal stanol proxies in lake surface sediments to assess the impact of human and herbivorous feces on TP lakes. The 75 investigated lakes were divided into three types (I, II, and III) according to cluster analysis of the fecal stanol ratios R1′ and R2′. Fecal stanols in type I lake surface sediments originate from a mixture of herbivorous and human feces; fecal stanols in type II lake surface sediments primarily originate from herbivorous feces with minimal human feces. In contrast, fecal stanols in type III lake surface sediments are mainly derived from herbivorous feces (coprostanol concentration > 100 ng/g), a mixed source of herbivorous feces and cholesterol reduction (coprostanol concentration of 10–100 ng/g), and in situ reduction of cholesterol (coprostanol concentration < 10 ng/g). Among the TP lakes investigated, 9 % had significant fecal contamination, 48 % had moderate or slight fecal contamination, and 43 % were uncontaminated. Domestic animal feces were the main source of fecal stanols in the surface sediments of moderately and slightly contaminated lakes in the central TP. There were 9 % of investigated lakes with significant fecal contamination from human and herbivorous feces; in contrast, 52 % of investigated lakes did not definitely show the presence of human fecal matter. This study has important implications for fecal contamination assessment in lake ecosystems and provides a reference for early herbivorous change and paleo-human activity research.

Tempeh Industry Wastewater Treatment using Mix Natural Adsorbents (Zeolite, Bentonite, Water Hyacinth-Activated Carbon): Effect of Mass Ratio and Dosage of Mix Adsorbents on Turbidity and pH

Adsorption is the process of agglomeration of dissolved substances in solution by the surface of an absorbent substance which makes the material enter and collect in an absorbent substance. Natural adsorbents that function to treat tempe liquid waste are zeolite, bentonite, and water hyacinth activated carbon. The purpose of this study was to determine the effect of the mass ratio and dose of natural adsorbents on the turbidity and pH values of tempe wastewater. The mass ratio variation used was the ratio of each material in the form of zeolite: bentonite: active carbon of water hyacinth in the form of R1 (1:1:1); R2 (2:1:1); R3 (1:2:1); and R4 (1:1:2). The adsorbent dose carried out was 1.5 gr; 3 grams; and 4.5 gr per 100 ml volume of liquid waste. The contact time between the adsorbent and the liquid waste is every 15, 30, 60, 90, 120, 150 minutes. Processing of tempe liquid waste was carried out in laboratory-scale batches with 120 rpm stirring. The analysis was carried out in form of turbidity, pH, COD, BOD, and TSS. The results showed that the adsorption was able to reduce turbidity and increase the pH level up to 99% by stirring the mass ratio R2 (2:1:1) for 150 minutes with a dose of 4.5 grams. It was found that the turbidity value decreased from 520.5 NTU to 2.47 NTU =ncrease in pH levels reaching 75% at 150 minutes of stirring at a dose of 4.5 grams. Decreased pH value from 3.7 to 6.4. The maximum adsorption capacity validation results were obtained based on the Frendulinch analysis of 7.07-49.75 mg/g with a Freundlich constant of 0.67-0.70 at a dose of 4.5 grams.

A Novel Algorithm for Improving the Prehospital Diagnostic Accuracy of ST-Segment Elevation Myocardial Infarction.

Early detection of ST-segment elevation myocardial infarction (STEMI) on the prehospital electrocardiogram (ECG) improves patient outcomes. Current software algorithms optimize sensitivity but have a high false-positive rate. The authors propose an algorithm to improve the specificity of STEMI diagnosis in the prehospital setting. A dataset of prehospital ECGs with verified outcomes was used to validate an algorithm to identify true and false-positive software interpretations of STEMI. Four criteria implicated in prior research to differentiate STEMI true positives were applied: heart rate <130, QRS <100, verification of ST-segment elevation, and absence of artifact. The test characteristics were calculated and regression analysis was used to examine the association between the number of criteria included and test characteristics. There were 44,611 cases available. Of these, 1,193 were identified as STEMI by the software interpretation. Applying all four criteria had the highest positive likelihood ratio of 353 (95% CI, 201-595) and specificity of 99.96% (95% CI, 99.93-99.98), but the lowest sensitivity (14%; 95% CI, 11-17) and worst negative likelihood ratio (0.86; 95% CI, 0.84-0.89). There was a strong correlation between increased positive likelihood ratio (r2 = 0.90) and specificity (r2 = 0.85) with increasing number of criteria. Prehospital ECGs with a high probability of true STEMI can be accurately identified using these four criteria: heart rate <130, QRS <100, verification of ST-segment elevation, and absence of artifact. Applying these criteria to prehospital ECGs with software interpretations of STEMI could decrease false-positive field activations, while also reducing the need to rely on transmission for physician over-read. This can have significant clinical and quality implications for Emergency Medical Services (EMS) systems.

The effect of strain on the crystallinity of carbonaceous matter: Application of Raman spectroscopy to deformation experiments

Raman spectroscopy, applied to the carbonaceous matter (CM) present in fault zones, is a potentially powerful tool to aid in the reconstruction of slip conditions, provided the respective effect of heating and strain can be disentangled. For this purpose, we have carried out static heating and deformation experiments on low-grade sediments containing disseminated CM particles and tracked the evolution of CM crystalline ordering (crystallinity) using Raman spectroscopy. Heating at high pressure (200 MPa), at varying temperatures (500 to 800 °C) and durations (3 to 1080 h) resulted in an increased crystallinity, which was observed by an increase in the intensity ratio of the Disordered Band over the Graphite Band (Intensity Ratio R1 parameter) of the Raman spectra. The experimental relationship between R1, T and duration was compiled into a law of evolution, which was then used to design the deformation experiments. Experiments were performed in a Paterson rig at 150 MPa or in a Griggs-type rig at 1 GPa. We observed two types of deformation microstructures: (1) purely brittle ones, such as breccia along slip planes and (2) ductile ones, such as foliated layers, resulting from grain reorientation and comminution along with dissolution precipitation. In all deformation microstructures, an increase in R1 is visible and interpreted to be the result of higher crystallinity of carbonaceous particles. Such increase is negligible in breccia, but is significant, up to 40%, in ductile deformation zones. The slow strain rates prevailing in ductile deformation prevented any local temperature increase, therefore the increase in crystallinity of the CM can be solely attributed to deformation. Thus, in natural fault zone, the increased crystallinity of CM reported in the literature and interpreted to be the result of frictional heating during earthquakes might rather be the result of strain localization without transient temperature increase.

Abstract 13177: The Association Between Insufficient Valve Expansion and Aortic Valve Calcification for Transcatheter Valve Implantation With Self-Expandable Valve

Background: Transcatheter aortic valve implantation (TAVI) has emerged as the preferred treatment for severe aortic stenosis. Nevertheless, severe calcification remains a factor leading to insufficient valve expansion and paravalvular leakage (PVL) after TAVI, mainly when using the self-expandable valve. We aimed to investigate the relationship between calcification and valve expansion using pre- and post-operative computed tomography (CT) scans, by comparing with valve phantoms as a reference standard. Methods: We enrolled 62 consecutive patients (mean age: 84.2 ± 4.4 years, 23 male) who underwent TAVI with the Evolut PRO+. We measured the aortic valve's calcium volume (Ca-Vol) by contrast-enhanced CT. The shorter diameter (mm) and the area (cm 2 ) of the base of the implanted valve were measured. We performed CT scans of valve phantoms for each size and defined the measured shorter diameter and the base area as the reference standard. We calculated the insufficiency of valve expansion as the ratio of the patient valve's shorter diameter and base area to that of the phantom valve. PVL was defined as more than mild regurgitation by transthoracic echocardiography. Results: The base area of valve phantoms was 3.6, 4.1, 6.4, and 8.4 cm 2 for 23, 26, 29, and 34 mm, respectively. The shorter diameter and base area of the implanted valve were 15.7 ± 2.6, 15.2 ± 2.8, 17.3 ± 4.0, 23.9 ± 1.8 mm, and 2.7 ± 0.7, 2.5 ± 0.6, 3.4 ± 1.0, and 6.2 ± 1.6 cm 2 for 23, 26, 29, and 34 mm (n=4, 31, 24, and 3, respectively). Significant inverse correlations were observed between Ca-Vol and shorter diameter ratio (r 2 = 0.1, P = 0.009), area ratio (r 2 = 0.1, P = 0.006), and PVL (r 2 = 0.4, P &lt; 0.001), respectively. On the other hand, there was no significant correlation between area ratio and PVL (r 2 = 0.004, P = 0.6). Conclusion: Severe calcification in the aortic valve was associated with insufficient valve expansion and PVL for the Evolut PRO+.

Organic carbon enables the biotic engineering of beneficial soil structure in Profundihumic and Haplic Ferralsols

AbstractWe investigated how organic matter may, directly and indirectly, modify the porosity of Ferralsols, that is, deeply weathered soils of the tropics and subtropics. Although empirical and anecdotal evidence suggests that organic matter accumulation may increase porosity, a mechanistic understanding of the processes underlying this beneficial effect is lacking, especially so for Ferralsols. To achieve our end, we leveraged the fact that the Profundihumic qualifier of Ferralsols (PF) is distinguished from Haplic Ferralsols (HF) by both a much larger average carbon content in the first 1 m of soil depth (19 kg C m−3 in PF vs. 10 kg C m−3 in HF) and a significantly lower bulk density (1.05 ± 0.08 kg L−1 in PF vs. 1.21 ± 0.05 kg L−1 in HF). Through exhaustive modelling of carbon – bulk density relationships, we demonstrate that the lower bulk density of PF cannot be satisfactorily explained by a simple dilution effect. Rather, we found that bulk density correlated with carbon content when combined with carbon: nitrogen ratio (r2 = 0.51), black carbon content (r2 = 0.75), and Δ14C (r2 = 0.81). Total pore space was greater in PF (61 ± 3%) than in HF (55 ± 2%), but x‐ray computed tomography revealed that pore space inside soil aggregates of 4–5 mm diameter does not vary between the studied Ferralsols. We further observed nearly twice as many roots and burrows in PF compared with HF. We thus infer that the mechanism responsible for the increase in porosity is most likely an enhancement of resource availability (e.g., energy, carbon, and nutrients) for the organisms (earthworms, ants, termites, etc.) that physically displace soil particles and promote soil aggregation. As a result of increased resource availability, soil organisms can create especially the mesoscale structural soil features necessary for unrestricted water flow and rapid gas exchange. This insight paves the way for the development of land management technologies to optimize the physical shape and capacity of the soil bioreactor.

Resonance Quantization in the Absorption Spectra of Concentric Double Gold Nanoshells: A Numerical Study

AbstractConcentric double metallic shells (CDMSs) are strong candidates for photothermal-based therapy, wherein they utilize their tuned plasmon resonance in the near-infrared region via particle coupling factor fitting. Tuning the resonance of CDMSs to the desired near-infrared region is crucial considering the shift caused by variations in their design parameters. In this study, we investigated the effects of these parameters using full-wave electromagnetic analysis to highlight the dominant factors affecting the resonance shift in the absorption spectra of CDMSs. With systematic variations, our simulation data outlined the direct influence of the outer and inner nanoshells’ (NS2 and NS1) aspect ratios r2 and r1, respectively, on the coupling factor (rT) aptitude for resonance tuning. For example, a CDMS with r2 = r1 = 0.8 shows coupling manifestation between NS2 and NS1 with rT as low as 0.2. However, we need the value of rT to be at least 0.6 for a CDMS with r2 = r1 = 0.4. Moreover, the dominant factors of the localized surface plasmon resonance shifts were determined by examining the mismatched parameter values of the same particle and found them to be related to NS2. We demonstrated how these factors are related to the complexity of localized surface plasmon resonance peak shifting and splitting in the absorption spectra of CDMSs. Our findings are expected to greatly improve the design of nanoparticles to optimize their responses in photothermal-based applications.

Double pulsed field gradient diffusion MRI to assess skeletal muscle microstructure.

Preliminary study to determine whether double pulsed field gradient (PFG) diffusion MRI is sensitive to key features of muscle microstructure related to function. The restricted diffusion profile of molecules in models of muscle microstructure derived from histology were systematically simulated using a numerical simulation approach. Diffusion tensor subspace imaging analysis of the diffusion signal was performed, and spherical anisotropy (SA) was calculated for each model. Linear regression was used to determine the predictive capacity of SA on the fiber area, fiber diameter, and surface area to volume ratio of the models. Additionally, a rat model of muscle hypertrophy was scanned using a single PFG and a double PFG pulse sequence, and the restricted diffusion measurements were compared with histological measurements of microstructure. Excellent agreement between SA and muscle fiber area (r2 = 0.71; p < 0.0001), fiber diameter (r2 = 0.83; p < 0.0001), and surface area to volume ratio (r2 = 0.97; p < 0.0001) in simulated models was found. In a scanned rat leg, the distribution of these microstructural features measured from histology was broad and demonstrated that there is a wide variance in the microstructural features observed, similar to the SA distributions. However, the distribution of fractional anisotropy measurements in the same tissue was narrow. This study demonstrates that SA-a scalar value from diffusion tensor subspace imaging analysis-is highly sensitive to muscle microstructural features predictive of function. Furthermore, these techniques and analysis tools can be translated to real experiments in skeletal muscle. The increased dynamic range of SA compared with fractional anisotropy in the same tissue suggests increased sensitivity to detecting changes in tissue microstructure.

PGS-Explorer: A web-based meta-analysis tool for polygenic scores.

e13538 Background: In clinical cancer prevention, polygenic score models (PGS) have focused on the aggregation of effects from multiple genetic variants. PGS models have the power to inform the risk of developing specific traits, such as cancer. The PGS Catalog is an open repository of published models, which currently has 573 models for various types of cancers. Despite all the metadata provided, selecting an appropriate model to use in clinical applications is a challenging task. Here we present a methodology and platform to support decision-making on the selection of those models. Methods: We developed a web-based tool to explore and compare different models available in the PGS catalog. First, we performed data cleaning of all available metadata and loaded them into our platform. Our tool shows the evaluation metrics by performance, development method, ancestry, and covariates. Then, hypothesis generation can happen through the exploration of our visualization tool. Finally, we present the results for all cancer models in a systematic approach to identify best practices to follow. We focused on breast, prostate, lung and skin cancer models, evaluated with three metrics: AUC, Odds Ratio (OR), and Nagelkerke's Pseudo R²; in European ancestry testing sets. Results: Until Jan 2023, there were 254, 126, 124, and 42 models evaluated on European individuals for breast, skin, prostate, and lung cancer traits. Their average AUCs were 0.62, 0.66, 0.66, and 0.6, respectively. Not all models were evaluated for AUC, but it was the most frequently used metric. Meanwhile, their average OR was 1.47, 1.71, 1.3, and 1.43, respectively; and their average pseudo R² was 0.03, 0.08, 0.03, and 0.03 respectively. Regarding covariates, age, sex and principal components were significant to improve the accuracy of models across all cancer types. The best performing models for breast cancer were SNPnet, Lasso, and PRS-CS; for prostate cancer were SNPnet, PRS-CS, and GWAS-based selection; for lung cancer SNPnet, LASSO, and Prunning/Clumping and Thresholding; and for skin cancer, were SNPnet and GWAS-based selection. Conclusions: Our PGS explorer allows the identification of relevant characteristics for model selection. Prostate cancer models showed the best performance, and should be considered for prospective clinical validation. Models developed using SNPnet, LASSO, GWAS, and PRS-CS showed the best performance, but promising but barely used methods (e.g. LDpred2, PRSice-2, Elastic Net), should also be considered. Most models evaluated were trained using European cohorts, which limits the ability to estimate the accuracy of these models in other ancestries. We recommend strengthening the collection and further sequencing of multi-ethnic ancestries. In the future, a fair evaluation pipeline could shed more light about PGS performance. PGS Explorer is publicly available to the overall scientific community in our website ( pgs.amphorahealth.com ).

Comparing Urban Anthropogenic NMVOC Measurements With Representation in Emission Inventories—A Global Perspective

AbstractEmission inventories are a critical basis for air quality and climate modeling, as well as policy decisions. Non‐methane volatile organic compounds (NMVOCs) are key precursor compounds in ozone and secondary organic aerosol formation. Accurately representing NMVOCs in emission inventories is crucial for understanding atmospheric chemistry, the impact of policy measures, and climate projections. Improving NMVOC representation in emission inventories is fraught with challenges, ranging from the lack of (long‐term) NMVOC measurements, limited efforts in updating emission factors, to the diversity of NMVOC species reactivity. Here we take an initial step to evaluate the representation of urban NMVOC speciation in an emission inventory (EDGARv4.3.2 and EDGARv6.1) at the global level. To compare the urban measurements of NMVOCs to the emission inventory estimates, ratios of individual NMVOCs to acetylene are used. Owing to limitations in measurement data and grouping of NMVOCs in emission inventories, the comparison includes only a limited number of alkanes, alkenes, and aromatics. Results show little to no agreement between the ratios in the observations and those in the global emission inventory for the species compared (r2 0.01–0.20). This could be related to incorrect speciation profiles and/or spatial allocation of NMVOCs to urban areas. Regional emission inventories show better agreement among the ratios (r2 0.43–0.70). The inclusion of oxygenated species in NMVOC measurements, as well as greater global coverage of measurements could improve representation of NMVOC species in emission inventories, and a mosaic of regional inventories may be a better approach.