2D Concentration Research Articles

Diagnostic approach to rickets: an Endocrine Society of Bengal (ESB) consensus statement.

Rickets, one of the leading causes of bony deformities and short stature, can be calciopenic (inciting event is defective intestinal calcium absorption) or phosphopenic (inciting event is phosphaturia). Early diagnosis and timely treatment of rickets are crucial for correction of the limb deformities. Guidelines exist for nutritional rickets, but the diagnosis and management of the relatively uncommon forms of rickets are complex. This consensus aims to formulate a simplified diagnostic approach for rickets, especially in resource-limited settings. The consensus statement has been formulated by a 29-member committee from the Endocrine Society of Bengal. The process included forming a working group, conducting a literature review, identifying controversies, drafting, and discussion at a consensus meeting. Participants rated their agreement with the clinical practice points, and a 70% consensus was required. Input integration and further review led to the final consensus statements. Children with suspected rickets should initially be examined for distinctive skeletal deformities. The diagnosis of rickets should be confirmed with characteristic radiographic abnormalities. It is advisable to order tests for serum calcium, inorganic phosphorus (Pi), liver function, 25-hydroxyvitamin D (25OHD), parathyroid hormone, creatinine, and potassium in all patients with rickets. In cases of refractory rickets, it is also recommended that assessments be conducted for spot urine calcium, Pi, creatinine, and, blood gas analysis. In children with rickets and metabolic acidosis, tests for glycosuria, uricosuria, aminoaciduria, low molecular weight proteinuria, and albuminuria should be conducted. In children with resistant calciopenic rickets and sufficient serum 25OHD levels, serum 1,25(OH)2D concentration should be tested. 1,25(OH)2 D and fibroblast growth factor 23 estimation is useful for certain forms of phosphopenic rickets.

Significant role of 1,25-dihydroxyvitamin D on serum calcium levels after total thyroidectomy: a prospective cohort study.

Although active vitamin D (VD) has been used both preoperatively and postoperatively to prevent hypocalcemia risk in patients undergoing total thyroidectomy, the role of 1,25-dihydroxyvitamin D (1,25(OH)2D) has not been examined. This study comprehensively investigated the effects of 1,25(OH)2D on calcium (Ca) concentrations after total thyroidectomy. Serum Ca, parathyroid hormone (PTH), and 1,25(OH)2D levels were measured in 82 patients with thyroid disease before and after surgery. Serum Ca, PTH, and 1,25(OH)2D levels decreased significantly on the morning of the first postoperative day. Notably, the decrease in 1,25(OH)2D concentration was significantly lower than that of PTH concentration (10.5 ± 33.4% vs. 52.1 ± 30.1%, p<0.0001), with 28% of patients showing increases in 1,25(OH)2D. The only factor predicting a postoperative 1,25(OH)2D decrease was a high preoperative 1,25(OH)2D concentration. Postoperative 1,25(OH)2D concentrations, as well as the magnitude and rate of decrease from preoperative levels, showed strong positive correlations with preoperative 1,25(OH)2D concentrations (p<0.0001 for all three variables) but not with PTH concentrations. These findings suggest that 1,25(OH)2D concentrations after thyroidectomy were more strongly dependent on preoperative concentrations than on the effect of PTH decrease and were relatively preserved, possibly preventing sudden severe postoperative hypocalcemia. A high 1,25(OH)2D level was the most important preoperative factor for hypocalcemia (<2 mmol/L; p<0.05) on the first postoperative day; however, only PTH decrease was statistically significant (p<0.001) when intraoperative factors were added. In the PTH >10 pg/mL group, the decrease in 1,25(OH)2D levels was significantly associated with postoperative hypocalcemia (p<0.05). Similarly, in the PTH levels >15 pg/mL group, a decrease in 1,25(OH)2D concentration was a significant factor, and the amount of PTH decrease was no longer significant. 1,25(OH)2D plays an important role in preventing sudden, severe hypocalcemia due to decreased PTH levels after total thyroidectomy, whereas high preoperative 1,25(OH)2D levels are a significant risk factor for postoperative hypocalcemia. Optimizing preoperative protocols to adjust Ca, PTH, and 1,25(OH)2D levels to improve the management of patients undergoing total thyroidectomy and to prevent extreme intraoperative PTH decreases may reduce the risk of hypocalcemia.

Age-dependent changes in plasma concentrations of 25-hydroxyvitamin D may complicate vitamin D status assessment of immature cats.

Vitamin D deficiency and excess in clinically presented cats conventionally is diagnosed by comparison of patient plasma 25-hydroxyvitamin D (25 (OH)D) concentration with plasma reference intervals determined in healthy adult cats. For immature cats, validity of this vitamin D status assessment method is uncertain. The overall objective was determination of whether plasma concentration of 25 (OH) D and other vitamin D metabolites in immature cats markedly change with developmental age as has been reported in other species. Four male and 4 female domestic short-hair kittens from weaning were continuously presented a single nutritionally adequate growth-diet. Concentrations of 25 (OH) D and 24,25-dihydroxyvitamin D (24,25 (OH)2D), and calcitriol were quantified in plasma of jugular venous blood collected at 12, 15, 18, and 21 weeks and 1 year of age. Plasma was liquid and solid-phase extracted and fractionation by normal-phase HPLC, and 25 (OH) D and 24,25 OH)2D quantified by reverse-phase HPLC-UV and calcitriol by RIA. Plasma 3-epi-25 (OH) D and 25 (OH) D concentrations increased (p < 0.001) with age so that by study end the concentrations rose by 1-and 2-fold, respectively. Concentrations of 3-epi-25 (OH) D relative to 25 (OH) D were 30% at 12 weeks and 20% at 1 year. Between ages 12 and 21 weeks, rises in 25 (OH) D concentration were positively correlated with body weight gains (ρ = 0.952, p < 0.001) and 24,25 (OH)2D concentrations were consistently greater than 25 (OH) D concentrations (p < 0.001). At 1 year of age, concentrations of 24,25 (OH)2D declined below those of 25 (OH) D and 3-epi-24,25 (OH)2D consistency occurred in low concentrations. Vitamin D2 metabolites and sex differences in metabolite concentrations were not observed. Reliance on quantification of plasma 25 (OH) D concentration for vitamin D status assessment in kittens may be confounded by developmental changes in 25 (OH) D independent of vitamin D intake. High 24,25 (OH)2D concentration and occurrence of 3-epi-25 (OH) D in plasma additionally may interfere with the quantification.

The impact of age on vitamin D receptor expression, vitamin D metabolism and cytokine production in ex vivo Rhodococcus equi infection of equine alveolar macrophages

Rhodococcus equi (R. equi), a pneumonia-causing intracellular bacterium, results in significant morbidity and mortality in young foals, while healthy adult horses rarely develop disease. Survival and replication within alveolar macrophages (AMφ) are the hallmarks of R. equi’s pathogenicity. The vitamin D receptor (VDR) and its ligand, the active vitamin D metabolite 1,25(OH)2D, are important in immune responses to intracellular bacteria. The vitamin D/VDR pathway regulates the downstream production of cytokines in infected human AMφ. The immunomodulatory role of the vitamin D/VDR pathway in equine leukocytes is unknown. The objective of the current study was to determine the impact of R. equi infection and age on synthesis of 1,25(OH)2D, VDR expression, and cytokine production in an ex vivo model of R. equi infection in equine AMφ. AMφ were collected from ten healthy foals at 2-, 4- and 8-weeks old and from nine healthy adult horses once via bronchoalveolar lavage. AMφ were mock infected (CONTROL) or infected with a virulent laboratory strain of R. equi for 7 days (INFECTED). VDR expression was determined via RT-qPCR from cell lysates. 1,25(OH)2D and cytokines were measured in cell supernatant by immunoassays. VDR expression was impacted by age (P = 0.001) with higher expression in AMφ from 8-week-old foals than from 2-week-old foals and adults. There was no significant effect of infection in foal AMφ, but in adults, relative VDR expression was significantly lower in INFECTED AMφ compared to CONTROL AMφ (P = 0.002). There was no effect of age or infection on 1,25(OH)2D concentration (P > 0.37). Mean TNFα production was significantly higher from INFECTED compared to CONTROL AMφ from 4- and 8-week-old foals and adults (P < 0.005). Mean IFNγ production was significantly higher from AMφ from foals at 8-weeks-old compared to 2-weeks-old (P = 0.013) and higher from INFECTED AMφ than from CONTROL AMφ in foals at 4-weeks-old and in adults (P < 0.027). The proportion of samples producing IL-1β and IL-10 was also significantly higher from INFECTED compared to CONTROL AMφ isolated from 4-week-old foals (P < 0.008). Similarly, in adult samples, IL-17 was produced from a greater proportion of INFECTED compared to CONTROL samples (P = 0.031). These data document age-associated changes in VDR expression and cytokine production in equine AMφ in response to R. equi infection. This preliminary investigation supports the need for further research to fully elucidate if the vitamin D pathway has an immunomodulatory role in the horse.

Functional Assessment of Vitamin D Status by a Novel Metabolic Approach: The Low Vitamin D Profile Concept.

Determining serum 25-hydroxyvitamin D [25(OH)D], 24,25-dihydroxyvitamin D [24,25(OH)2D] and the vitamin D metabolite ratio (VMR) allows the identification of individuals with a low vitamin D metabolite profile. Here, we evaluated if such a functional approach provides superior diagnostic information to serum 25(OH)D alone. 25(OH)D, 24,25(OH)2D, and the VMR were determined in participants of the DESIRE (Desirable Vitamin D Concentrations, n = 2010) and the LURIC (Ludwigshafen Risk and Cardiovascular Health, n = 2456) studies. A low vitamin D metabolite profile (vitamin D insufficiency) was defined by a 24,25(OH)2D concentration <1.2 ng/mL (<3 nmol/L) and a VMR <4%. Parathyroid hormone (PTH) and bone turnover markers were measured in both cohorts, whereas 10-year mortality data was recorded in LURIC only. The median age in DESIRE and LURIC was 43.3 and 63.8 years, respectively. Median 25(OH)D concentrations were 27.2 ng/mL (68.0 nmol/L) and 15.5 ng/mL (38.8 nmol/L), respectively. Serum 25(OH)D deficiency, defined as <20.2 ng/mL (<50 nmol/L), was present in 483 (24.0%) and 1701 (69.3%) participants of DESIRE and LURIC, respectively. In contrast, only 77 (3.8%) and 521 (21.2%) participants had a low vitamin D metabolite profile. Regardless of the serum 25(OH)D concentration, a low vitamin D metabolite profile was associated with a significantly higher PTH, accelerated bone metabolism, and higher all-cause mortality than an unremarkable vitamin D metabolite profile. The personalized assessment of vitamin D status using a functional approach better identifies patients with accelerated bone metabolism and increased mortality than the use of a fixed 25(OH)D cutoff of 20 ng/mL (50 nmol/L).

Analytical performance specifications for the measurement uncertainty of 24,25-dihydroxyvitamin D examinations.

The exploration of the metabolites in the degradation pathways of vitamin D (VTD) has gained importance in recent years and simultaneous quantitation of twenty-five-hydroxy vitamin D (25(OH)D) mass concentration together with 24,25-dihydroxyvitamin D (24,25(OH)2D) has been proposed as a newer approach to define VTD deficiency. Yet, no data are available on 24,25(OH)2D biological variation (BV). In this study, we evaluated 24,25(OH)2D's BV on the European Biological Variation Study (EuBIVAS) cohort samples to determine if analytical performance specifications (APS) for 24,25(OH)2D could be generated. Six European laboratories recruited 91 healthy participants. 25(OH)D and 24,25(OH)2D concentrations in K3-EDTA plasma were examined weekly for up to 10weeks in duplicate with a validated LC-MS/MS method. The Vitamin D Metabolite Ratio (24,25(OH)2D divided by 25(OH)D×100) was also calculated at each time point. Linear regression of the mean 24,25(OH)2D concentrations at each blood collection showed participants were not in steady state. Variations of 24,25(OH)2D over time were significantly positively associated with the slopes of 25(OH)D concentrations over time and the concentration of 25(OH)D of the participant at inclusion, and negatively associated with body mass index (BMI), but not with age, gender, or location of the participant. The variation of the 24,25(OH)2D concentration in participants over a 10weeks period was 34.6%. Methods that would detect a significant change linked to the natural production of 24,25(OH)2D over this period at p<0.05 would need a relative measurement uncertainty (u%)<14.9% while at p<0.01, relative measurement uncertainty should be <10.5%. We have defined for the first time APS for 24,25(OH)2D examinations. According to the growing interest in this metabolite, several laboratories and manufacturers might aim to develop specific methods for its determination. The results presented in this paper are thus necessary prerequisites for the validation of such methods.

2D dimensionless numbers in isothermal fuel cells with smooth electrocatalysts

One of the problems in the optimization of a fuel cell performance is the operation prediction for short and long-time behaviours.The employ of exact analytical functions for picturing the distribution of potential and current densities in 2D polymer electrolyte membrane fuel cells, generalizes the study and reduces large computational times for each experimental situation. Therefore, we foresee analytical solutions for mass balance equations using the asymptotic velocity equations (normal and tangential coordinates) to obtain a 2D concentration, current and overpotential profiles for smooth platinum catalysts. Dimensionless numbers are deduced,i.e.Wagner, Damkoehler and Graetz to characterize the fuel cell performance, first with a 1D approach and also along 2D coordinates. Besides, the complete polarization curve is predicted comparing the theoretical results with the proper variations of electrochemical magnitudes in a single home-made hydrogen/oxygen 200 cm2polymer electrolyte membrane fuel cell.

Line-focus solar concentration 10 times higher than the 2D thermodynamic limit.

Line-focus solar concentrators have traditionally been limited by the 2D concentration limit due to the continuous translational symmetry in these systems. This limit is orders of magnitude lower than the 3D limit, severely limiting the achievable concentration ratio compared to point-focus systems. We propose a design principle for line-focus solar concentrators that bypasses this 2D limit, while maintaining a trough-like configuration and only requiring single-axis external solar tracking. This is achieved by combining the concept of étendue squeezing with the concept of tracking integration. To demonstrate the principle, we present a design example that achieves a simulated average yearly efficiency of 80% at a geometric concentration of 335x under light with a ±9mrad angular distribution and horizontal single-axis external tracking. We also show how the same design principle can achieve a line-focus with 1563x geometric concentration at 90% efficiency if design constraints are relaxed by foregoing tracking-integration and assuming two-axis external solar tracking. This design principle opens up the design space for high-concentration line-focus solar concentrators, and may contribute to a reconsideration of the trade-off between concentration and acceptance angle in such systems.

A Novel Approach for Visualizing Mixing Phenomena of Reactive Liquid-Liquid Flows in Milli- and Micro-Channels

Modular milli- and micro-structured systems represent a promising approach to exploit the potential of micro-process technology, including precise reaction control and scale-up. A major drawback of micro-structured devices is fouling and mixing mechanisms need to be investigated phenomenologically to better understand the processes that lead to fouling. Previous work was conducted to resolve 3D concentration fields by means of Laser-Induced Fluorescence (LIF) using a Confocal Laser Scanning Microscope (CLSM) (Frey et al., J Flow Chem, 2021, 11, 599–609). While the CLSM-LIF method yields detailed insight into concentration fields down to a few micrometers, it is limited to stationary flow structures only. Aubin et al. (Chemical Engineering Science, 2010, 65, 2065–2093) give a comprehensive review of methods to analyze mixing behavior. Most recent optical measurement methods rely on the detection of a single compound in mixtures. In case of reactive mixing, Tthe state of the art procedures to locally visualize micro mixing relies on tracking a reaction product which forms on molecular scale. In literature, only small micro-structures are manufactured from transparent materials, however larger milli-structures often lack optical accesses with sufficient quality. Selective laser-induced etching (SLE) is a new technique which enables the fabrication of larger milli-structures in transparent materials that are relevant for industry-scale applications. This work develops a method based on a concept of Kexel et al. (Chemie Ingenieur Technik, 2021, 93, 830–837) visualizing the selectivity of a competitive-consecutive gas-liquid reaction in a Taylor bubble flow. The main goal of this work is the analysis of the absorbance spectra of bromothymol blue (BTB) at different pH values in a miscible liquid-liquid system in a fused silica split-and-recombine mixer. The milli-structure of the mixer is manufactured by means of SLE. Backlight at different wavelengths is pulsed matching the recording frequency. In contrast to conventional UV/Vis setups, the absorbance is recorded locally within the mixer. The proposed method yields the 2D concentration distribution of multiple species with high spatial resolution. The spatially resolved reactant and product distribution unveils micro mixing and can yield important information about local root causes of fouling.

Encapsulated droplet interface bilayers as a platform for high-throughput membrane studies.

Whilst it is highly desirable to produce artificial lipid bilayer arrays allowing for systematic high-content screening of membrane conditions, it remains a challenge due to the combined requirements of scaled membrane production, simple measurement access, and independent control over individual bilayer experimental conditions. Here, droplet bilayers encapsulated within a hydrogel shell are output individually into multi-well plates for simple, arrayed quantitative measurements. The afforded experimental throughput is used to conduct a 2D concentration screen characterising the synergistic pore-forming peptides Magainin2 and PGLa. Maximal enhanced activity is revealed at equimolar peptide concentrations via a membrane dye leakage assay, a finding consistent with models proposed from NMR data. The versatility of the platform is demonstrated by performing in situ electrophysiology, revealing low conductance pore activity (∼15 to 20 pA with 4.5 pA sub-states). In conclusion, this array platform addresses the aforementioned challenges and provides new and flexible opportunities for high-throughput membrane studies. Furthermore, the ability to engineer droplet networks within each construct paves the way for “lab-in-a-capsule” approaches accommodating multiple assays per construct and allowing for communicative reaction pathways.

Chemical equilibria in the quaternary reactive mixtures and liquid phase splitting: a system with n-amyl acetate synthesis reaction at 318.15 K and 101.3 kPa

A new set of experimental data on chemically equilibrium compositions for the acetic acid – n-amyl alcohol – n-amyl acetate – water systems at 318.15 K and 101.3 kPa is presented. It was found that both homogeneous and heterogeneous regions of compositions correspond to the surface of chemical equilibrium. The values of compositions were obtained by gas chromatography analysis. The critical states of liquid–liquid equilibrium were experimentally determined by the “cloud point“ technique; the chemically equilibrium critical point was located. Corresponding diagrams in 3D (the composition tetrahedron) and 2D (the square of transformed compositions variables α) concentration spaces are constructed. The NRTL model was applied to correlate liquid–liquid equilibrium data. The concentration and thermodynamic constants of chemical equilibrium were calculated using UNIFAC model.

2D electrons floating on a suspended atomically thin dielectric

The 2D electrons trapped in vacuum near the atomically thin dielectric (ATD, mono- or N-layer film of h-BN or transition metal dichalcogenide) are considered. ATD is suspended above the back gate and forms the capacitor, which is controlled by the biased voltage determining 2D concentration, n2D. It is found that the leakage current through ATD is negligible, and the effect of the polarizability of ATD is weak if N≤5. At temperatures T=0.1–15 K and n2D=5×108–1010cm−2, one deals with the Boltzmann liquid having a macroscopic thickness of ∼100 A. Due to the bending of ATD, the quadratic dispersion law of the flexural vibrations is transformed into the linear one at small wave vectors. The scattering processes of the electrons caused by these phonons or the monolayer islands on ATD are examined and the momentum and energy relaxation rates are analyzed based on the corresponding balance equations. The momentum relaxation times vary over orders of magnitude in the above region (T, n2D) and N. The response may change from the polaron transport, for a perfect single-layer ATD at low T and high n2D, to the high-mobility (≥107cm2/Vs) regime at high T and low n2D. The quasi-elastic energy relaxation due to phonon-induced scattering is considered, and the conditions for the heating of electrons by a weak in-plane electric field are found.

Serum 24,25-dihydroxyvitamin D level in general Korean population and its relationship with other vitamin D biomarkers

BackgroundVitamin D status is presently assessed by measuring total serum concentration of 25-hydroxyvitamin D [25(OH)D]. However, 25(OH)D concentration alone might not accurately reflect vitamin D status owing to its weak relationship with various clinical indices and inconsistency across races. Recently, 24,25-dihydroxyvitamin D [24,25(OH)2D] and vitamin D metabolite ratio [VMR; ratio of 24,25(OH)2D to 25(OH)D] have emerged as vitamin D biomarkers. The present study aimed to determine the values of 24,25(OH)2D and VMR in healthy Koreans and compare them with other vitamin D biomarkers, including 25(OH)D and bioavailable 25(OH)D.MethodsSerum samples and medical information were collected from 200 individuals (100 females and 100 males) who underwent general health checks without self-reported symptoms. We measured 24,25(OH)2D concentration using liquid chromatography–tandem mass spectrometry, and concentrations of 25(OH)D and vitamin D binding protein using immunoassays. VMR and bioavailable 25(OH)D concentration were calculated using the above data. Serum parathyroid hormone level, and bone mineral density (BMD) data were collected as clinical outcomes, and the effects of the vitamin D markers on them were tested using multiple linear regression models.ResultsThe mean values of 25(OH)D, 24,25(OH)2D, VMR, and bioavailable 25(OH)D were 24.3 ± 8.5 ng/mL, 1.9 ± 1.1 ng/mL, 7.6 ± 2.5, and 3.2 ± 1.2 ng/mL, respectively. The concentration of 25(OH)D closely correlated with 24,25(OH)2D (R = 0.868, P < 0.001) and bioavailable 25(OH)D (R = 0.862, P < 0.001). No significant effects of 24,25(OH)2D, VMR, and bioavailable 25(OH)D were observed on the prediction of PTH and BMD in the multiple linear regression models.ConclusionOur study presents the distribution of 24,25(OH)2D concentration and VMR in Korean population for the first time. Overall, our data reaffirm that 25(OH)D is the primary marker for determining vitamin D status in the general population.

Multi-scenario validation of CALMET-RIMPUFF for local-scale atmospheric dispersion modeling around a nuclear powerplant site with complex topography

The CALMET-RIMPUFF is composed of the California Meteorological Model and the Risø Mesoscale PUFF model, which provides refined atmospheric dispersion modeling for nuclear emergency response. Because the performance of an atmospheric dispersion model can be case-sensitive, a multi-scenario validation is important to understand a model's behavior and limits. In this study, a multi-scenario validation of CALMET-RIMPUFF was performed based on six wind tunnel experiments simulating a real China's nuclear powerplant site with complex topographies and dense buildings. The CALMET-RIMPUFF simulations were compared with the measurements of the vertical wind profiles, 2D ground wind and concentration fields, both qualitatively and quantitatively. The results demonstrate that the CALMET-RIMPUFF can simulate the ground-level wind with acceptable accuracies. For vertical wind profiles, the accuracies show high dependencies on the local topography and building layout. The simulated ground concentrations generally agree well with the measurements, though the plume axis showed slight discrepancies from the measurements in three cases. Because the CALMET-RIMPUFF lacks a building effect module, it shows noticeable discrepancies in the building area. However, such discrepancies do not propagate to the downwind mountainous and sea areas, which the accuracies are quite satisfactory. Thus, the CALMET-RIMPUFF is capable for local-scale modeling at this site.

Measurement enhancement of TDLAS based on variable weighted cross-correlation tomography for the simultaneous reconstruction of 2D temperature and concentration

Tunable diode laser absorption tomography is a technology that enables the visualization of 2D temperature and concentration in combustion fields. This study proposes a method called variable weighted cross-correlation tomography to improve the traditional two-wavelength scheme affected by signal noise and bias error. The proposed approach combines the multiplicative algebraic reconstruction technique and pattern matching at nine wavelengths by adding peak and bottom wavelengths. In addition, this method iteratively calculates using a corrective multiplication line-of-sight and a modified return process to simultaneously estimate the images of 2D temperature and concentration. Numerical tests are performed using various thermodynamic models with additive noise. The validation experiments involving premixed methane-air flames demonstrate the good agreement between the average relative error values of the reconstructed temperature and the temperature measured using thermocouple (3.32 %), which can be ascribed to the introduction of modified broadening coefficients.

Beyond the 2D limit: étendue-squeezing line-focus solar concentrators.

Line-focus solar concentrators are commonly designed by extruding a two-dimensional concentrator in the third dimension. For concentration in air, these concentrators are, by the nature of their design, limited by the two-dimensional solar concentration limit of 212×. This limit is orders of magnitude lower than the 45000× concentration limit for three-dimensional solar concentrators. Through the use of étendue squeezing, we conceptually show that it is possible to design line-focus solar concentrators beyond this 2D limit. This allows a concentrator to benefit from a line focus suitable for heat extraction through a tubular receiver, while reaching concentration ratios and acceptance angles previously unseen for line-focus concentrators. We show two design examples, achieving simulated 75× concentration and 218× concentration ratios, with a ±1∘ acceptance angle. For comparison, the 2D concentration limit is 57× at this acceptance angle. Étendue-squeezing line-focus solar concentrators, combined with recent developments in tracking integration, may enable the development of a new class of concentrated solar power systems.

Bioartificial injectable cartilage implants from demineralized bone matrix/PVA and related studies in rabbit animal model.

Functional cartilage tissue engineering needs a substantial, easy to handle scaffold with proper mechanical strength to repair defected area in articular cartilage. In this study, we report the development and characterization of demineralized bone matrix (DBM) in with a poly vinyl alcohol (PVA) to have a proper homogenous injectable scaffold. Injectabiliy of the biodegradable scaffolds, degradation rate, swelling ratio compression and tensile mechanical properties, and viability and proliferation of bone marrow mesenchymal stem cells (BM-MSCs) followed by differentiation of them In-vitro and In-vivo seeded within the scaffold were studied. It demonstrated that the PVA 20% could increase significantly (p < 0.05) the biodegradability of DBM after 720 hours.DBM with 20% of PVA scaffold has significantly higher (p < 0.05) compression and tensile mechanical strength and viscosity. SEM images showed a multilayer of cells on DBM scaffold incorporated with PVA 20%.BM-MSCs on scaffolds, DBM+PVA 20% had a significant growth rate (p < 0.0001) compare to 2D and low concentration of PVA after 21 days of culture. Viability of cells was significantly higher (p < 0.05) on DBM+PVA scaffold compare to DBM. DBM+PVA 20% enhanced cell viability (P < 0.05) compare to DBM scaffold. The PVA presence enhanced chondrogenesis differentiation at the cellular and molecular levels, as evidenced by increased COL II (P < 0.05) and SOX2 upregulation of Chondrogensis-specific genes (p < 0.001). Hyline-like cartilage covered the defect which was confirmed by microscopy and histology assessments. Having considered percentages of PVA with a constant amount of DBM, injectability, compressive mechanical properties, homogeneity of the scaffold, and providing sufficient surface area (12.25 cm2/ml) for cell attachment; 0.35 g/ml of DBM in 20% PVA (w/v) has applicable properties within the ranges of studies which can be proposed for the injectable engineered articular cartilage.

Four days high fat diet modulates vitamin D metabolite levels and enzymes in mice.

Obesity is classically associated with low serum total and free 25(OH)D. Hypotheses have been advanced to explain this observation but mechanisms remain poorly understood, and notably priming events that could explain such association. We investigated the impact of short-term high fat (HF) diet to investigate early events occurring in vitamin D metabolism. Male C57BL/6J mice were fed with a control diet (control group) and HF diet for 4 days. HF fed mice displayed similar body weight to control mice but significantly increased adiposity, together with a decrease of free 25(OH)D concentrations, which could be explained at least in part by a decrease of Cyp2r1 and Cyp3a11 expression in the liver. An increase of 1,25(OH)2D concentration was also observed and could be explained by a decrease of Cyp24a1 expression observed in the kidney. In white adipose tissue (WAT), no modification of vitamin D metabolites quantity detected by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Nevertheless, an increase of Cyp2r1 and Cyp27a1 mRNA expression and a decrease of Cyp27b1 mRNA expression could suggest a possible storage of 25(OH)D in WAT at long-term. Our data are supportive of an active role of HF diet in mediating a priming effect leading the well-established perturbation of the vitamin D metabolism associated with obesity, including a decrease of free 25(OH)D and modulation of expression of genes involved in vitamin D metabolism.

Effect Of Vitamin D3 Supplementation On Serum 1,25(OH) 2 D Status Of Athletes: Systematic Review And Meta-analysis

Vitamin D is an essential fat-soluble vitamin, which plays an important role in the maintaining of good health. Without sufficient vitamin D, people cannot absorb enough calcium, which is a primary component of the bone. In the past century, vitamin D deficiency is heavily studied and lots of scientists report that vitamin D deficiency is related to several health problems, such as osteoporosis, muscle aches and weakness. Vitamin D supplements and vitamin D fortified foods always have claims of bringing people health benefits including bone health and muscle function. PURPOSE: This study is designed to investigate the effects of vitamin D3 supplementation on serum 1,25(OH)2D among athletes. METHODS: Literature search of PubMed, Embase and Cochrane Library databases from inception to Sept. 2019 was accomplished. Duplicates were removed at the stage of title and abstract assessment with assistant from Mendeley tools and by notes from Cochrane library. RESULTS: 6 RCTs with 205 athletes (vitamin D3 = 107, placebo = 98) finally met inclusion criteria. 20 athletes were lost to follow-up and 185 athletes (vitamin D3 = 100, placebo = 85) were documented with complete result. The intervention of vitamin D3 significantly improved the level of serum 1,25(OH)2D (SMD 3.77, 95% CI: 1.88 to 5.66, P < 0.01). Among athletes with insufficient baseline serum 1,25(OH)2D, vitamin D3 daily dosage at 5000 IU for over 4 weeks led to serum 1,25(OH)2D concentration of 31.7 ng/ml. Athletes with sufficient serum 1,25(OH)2D level at baseline were recruited in only one study, and the participants were assigned to either vitamin D3 at a daily dosage of 3570 IU or placebo for 12 weeks, their serum 1,25(OH)2D sufficiency (VD: 37.2 ± 7.6 vs 45.6 ± 7.6; PL 38 ± 6.8 vs 32 ± 8.4) was well maintained above the cut-off boundary with improved serum 1,25(OH)2D status in supplementation group. CONCLUSIONS: Serum 1,25(OH)2D concentration was improved after supplementation in this meta-analysis. Additional well-designed RCTs with large number of participants from a variety of sports that examined the effect of vitamin D3 supplementation on serum 1,25(OH)2D concentrations are needed.

The development of the simultaneous reconstruction of 2D temperature and concentration using a 6-peaks algorithm for CT-TDLAS

A new reconstruction algorithm for a computed tomography-tunable diode laser absorption spectroscopy (CT-TDLAS) proposed for the measurements of two-dimensional temperature and concentration distribution of a gas flame. The characteristic wavelengths near 1388 nm where water vapor was detected, it used for the performance test of the proposed algorithm. The new algorithm is a 6-peaks algorithm, in which the absorptions at 6 representative wavelengths are used for the construction of the actual absorption spectra at a certain temperature of gas flame. Multiplicative algebraic reconstruction technique (MART) and scale & least mean squares (LMS) algorithms were adopted for data reconstructions. Mean squared error (MSE) was calculated during the iterative calculations for data reconstructions. In order to evaluate the performances of the new algorithm, a numerical test was performed by the use of phantom data in which two-dimensional distribution of temperature and concentration fields were set at 22 × 22 square mesh with Gaussian distribution. Further, the proposed algorithm has been adopted to calculate an actual temperature distribution inside a combustion engine, through which the performance of the newly proposed 6-peaks algorithm has been demonstrated theoretically and experimentally. It is highly expected that the proposed algorithm will be the most appropriate approach for calculating the temperature and concentration fields in CTTDLAS.