Trace-class operators on Hilbert modules and Haagerup tensor products

We show that the space of trace-class operators on a Hilbert module over a commutative C*-algebra, as defined and studied in earlier work of Stern and van Suijlekom (Journal of Functional Analysis, 2021), is completely isometrically isomorphic to a Haagerup tensor product of the module with its operator-theoretic adjoint. This generalises a well-known property of Hilbert spaces. In the course of proving this, we also obtain a new proof of a result of Stern-van Suijlekom concerning the equivalence between two definitions of trace-class operators on Hilbert modules.Comment: 13 page

Higher Vitamin D2 and 25(OH)D2, but Not Vitamin D3 Metabolites, in Bovine Plasma and Muscle from Grass-Based Finishing System, Compared to Concentrate

Meat and meat products are one of the largest contributors to vitamin D dietary intakes. Little is known, however, about how different animal husbandry practices and/or finishing diets might affect the vitamin D content of the animal. Therefore, this study aimed to investigate the effect of bovine finishing diet (grass vs. concentrate) on the 25(OH)D plasma concentrations of cattle and subsequent vitamin D content in beef. Cattle were fed grass (n = 7) or concentrate (n = 9) finishing diets for 15 weeks prior to slaughter. Bovine blood samples were collected at slaughter and plasma aliquots were stored (−80 °C) until analysis. Beef top rump from each animal was chilled for an ageing period of 21 days, then homogenised and frozen (−80 °C) until analysis. Bovine plasma samples were analysed for circulating 25(OH)D3, and 25(OH)D2 (nmol/L), and raw beef muscle (top rump) samples were analysed for vitamin D metabolites; vitamin D3, vitamin D2, 25(OH)D3 and 25(OH)D2 (µg/kg), all by LC-MS/MS. Total vitamin D activity was defined: [vitamin D3 + (25(OH)D3 × 5) + vitamin D2 + (25(OH)D2 × 5)]. Statistical analysis was conducted by SPSS with independent t tests used to compare groups; significance level p < 0.05. Data were presented as mean ± SD. A significantly higher plasma 25(OH)D2 concentration was observed in the grass finished cattle compared to the concentrate group (43.18 ± 11.75 vs. 16.56 ± 1.58 nmol/L, p < 0.002). No difference in plasma 25(OH)D3 concentrations was observed between groups. In beef top rump, the grass finishing diet resulted in a significantly higher mean ± SD vitamin D2 [0.07 ± 0.05 vs. 0.01 ± 0.01 µg/kg] and 25(OH)D2 [0.70 ± 0.16 vs. 0.25 ± 0.07 µg/kg] compared to concentrate finishing diet (both p < 0.001). Moreover, beef from grass finished cattle demonstrated a significantly higher total vitamin D activity compared to those in the concentrate group [9.52 ± 2.43 vs. 6.78 ± 2.00 µg/kg, p < 0.05]. No difference was observed for muscle vitamin D3 or 25(OH)D3 between groups. In conclusion, a more favourable bovine vitamin D profile, driven by vitamin D2 metabolites specifically (not vitamin D3), is reported from a grass-based finished system, compared to concentrate finishing. Further research is required to understand the impact of these findings for both agriculture practices and human nutrition

Improving vitamin D content in pork meat by UVB biofortification

Publication history: Accepted - 11 January 2023; Published online - 14 January 2023Vitamin D deficiency is prevalent worldwide and identification of alternative food-based strategies are urgently warranted. In two studies, 12-week old crossbred pigs (Duroc x (Large White x Landrace)) were exposed daily to narrowband UVB radiation for ∼10 weeks or control (no UVB exposure) until slaughter. In Study 1 (n = 48), pigs were exposed to UVB for 2 min and in Study 2 (n = 20), this duration was tripled to 6 min. All pigs were fed the maximum permitted 2000 IU vitamin D3/kg feed. Loin meat was cooked prior to vitamin D LC-MS/MS analysis. In Study 1, pork loin vitamin D3 did not differ between groups. Study 2 provided longer UVB exposure time and resulted in significantly higher loin vitamin D3 (11.97 vs. 6.03 μg/kg), 25(OH)D3 (2.09 vs. 1.65 μg/kg) and total vitamin D activity (22.88 vs. 14.50 μg/kg) concentrations, compared to control (P < 0.05). Pigs remained healthy during both studies and developed no signs of erythema. Biofortification by UVB radiation provides an effective strategy to further safely increase the naturally occurring vitamin D content of pork loin, alongside feed supplementationThis work was funded as part of a Department for the Economy (DfE) Co-operative Awards in Science and Technology (CAST) PhD studentship, supported by Devenish Nutrition Limited and Agri-Food Quest Competence Centre (AFQCC)

The impact of (poly)phenol-rich foods and extracts on flow-mediated dilation (FMD): a narrative review

Cardiovascular disease (CVD) remains the leading cause of morbidity and mortality worldwide, with endothelial dysfunction as a key precursor. Flow-mediated dilation (FMD), the gold-standard measure of endothelial function, is improved by (poly)phenol-rich foods and extracts, with increases of 1% FMD representing 13% reduced cardiovascular risk. This narrative review aims to evaluate the efficacy of various (poly)phenol-rich foods and extracts on endothelial function as measured by flow-mediated dilation (FMD) and assesses the feasibility of a food-first approach. Literature was systematically searched from databases including PubMed and Web of Science, focusing on human clinical trials. While all (poly)phenol-rich food groups demonstrate variable effects, berries (0.9–2.6%), cocoa (0.7–5.9%), and tea (1.2–4.8%) have the most robust evidence, consistently improving FMD, with chronic intake sustaining benefits. A large variance (0.8–8.7%) was observed with grape-derived (poly)phenols, making their effects difficult to substantiate without detailed compositional or metabolomic data; however, a few key studies highlight their potential. Citrus polyphenols also exhibit variable FMD responses (0.2–7.2%). However, strong mechanistic evidence supports their role in vascular health and nitric oxide (NO) bioavailability. Coffee exhibits a variable response, initially impairing FMD, likely due to caffeine, before later improving endothelial function as phenolic metabolites increase. Although estimated (poly)phenol intake in Western populations is high (∼1000–1200 mg day −1 ), it is primarily derived from tea, coffee, and cocoa, limiting exposure to diverse bioactive compounds. Moreover, the food matrix significantly influences bioavailability, with co-consumed components such as milk or sugar attenuating FMD responses. Interestingly, fortification and enrichment maintain bioactivity and may optimize intake, ensuring consistent and diverse delivery. Future research should refine dietary guidelines, establish intake thresholds, and explore fortification strategies to maximize cardiovascular benefits while considering dose–response relationships and long-term efficacy

La diversidad y la densidad de las epífitas vasculares en la Reserva Cerro Candelaria: La diferencia entre las alturas y dos tipos de bosque nublado en Ecuador

En el bosque nublado, las epífitas son muy comunes por la neblina, o la “lluvia horizontal,” que permite el crecimiento de plantas sobre otras plantas. También, las epífitas son contribuidoras importantes para el crecimiento y mantenimiento de un bosque nublado saludable. Las epífitas pueden estar afectadas por la deforestación, y este ensayo investiga las diferencias entre la distribución, la densidad, y la biodiversidad de las epífitas en el bosque nublado primario y secundario. El estudio consiste en cuadrantes realizados en cuatro niveles de altura, y en el bosque primario y secundario adentro y cerca de la Reserva Cerro Candelaria, todo en el corredor ecológico entre los parques nacionales ecuatorianos los Llanganates y El Sangay. Elegí estudiar solo epífitas vasculares. En los cuadrantes que estudié, no encontré una relación fuerte entre la riqueza de epífitas y el diámetro del árbol hospedero, pero hay diferencias de la distribución de los géneros entre el bosque primario y el bosque secundario. Hay más densidad en el número de epífitas con relación al diámetro del árbol en el bosque secundario que en el bosque primario. La diversidad es distintivamente más grande en el bosque primario que en el bosque secundario, y la composición de los géneros entre los dos tipos de bosque es muy distinta. También la dispersión de los individuos en sus géneros respectivos es más uniforme en el bosque primario que en el bosque secundario. La diversidad y la densidad de las epífitas en el bosque primario aumentaba en una relación directa con la altura, pero no había una correlación entre la densidad y la altura, ni entre la diversidad y la altura en el bosque secundario