The Abnormal Phenotypes of Cartilage and Bone in Calcium-Sensing Receptor Deficient Mice Are Dependent on the Actions of Calcium, Phosphorus, and PTH

Patients with neonatal severe hyperparathyroidism (NSHPT) are homozygous for the calcium-sensing receptor (CaR) mutation and have very high circulating PTH, abundant parathyroid hyperplasia, and severe life-threatening hypercalcemia. Mice with homozygous deletion of CaR mimic the syndrome of NSHPT. To determine effects of CaR deficiency on skeletal development and interactions between CaR and 1,25(OH)2D3 or PTH on calcium and skeletal homeostasis, we compared the skeletal phenotypes of homozygous CaR–deficient (CaR−/−) mice to those of double homozygous CaR– and 1α(OH)ase–deficient [CaR−/−1α(OH)ase−/−] mice or those of double homozygous CaR– and PTH–deficient [CaR−/−PTH−/−] mice at 2 weeks of age. Compared to wild-type littermates, CaR−/− mice had hypercalcemia, hypophosphatemia, hyperparathyroidism, and severe skeletal growth retardation. Chondrocyte proliferation and PTHrP expression in growth plates were reduced significantly, whereas trabecular volume, osteoblast number, osteocalcin-positive areas, expression of the ALP, type I collagen, osteocalcin genes, and serum ALP levels were increased significantly. Deletion of 1α(OH)ase in CaR−/− mice resulted in a longer lifespan, normocalcemia, lower serum phosphorus, greater elevation in PTH, slight improvement in skeletal growth with increased chondrocyte proliferation and PTHrP expression, and further increases in indices of osteoblastic bone formation. Deletion of PTH in CaR−/− mice resulted in rescue of early lethality, normocalcemia, increased serum phosphorus, undetectable serum PTH, normalization in skeletal growth with normal chondrocyte proliferation and enhanced PTHrP expression, and dramatic decreases in indices of osteoblastic bone formation. Our results indicate that reductions in hypercalcemia play a critical role in preventing the early lethality of CaR−/− mice and that defects in endochondral bone formation in CaR−/− mice result from effects of the marked elevation in serum calcium concentration and the decreases in serum phosphorus concentration and skeletal PTHrP levels, whereas the increased osteoblastic bone formation results from direct effects of PTH

Quantifying evolution of soot mixing state from transboundary transport of biomass burning emissions

Incomplete combustion of fossil fuels and biomass burning emit large amounts of soot particles into the troposphere. The condensation process is considered to influence the size (Dp) and mixing state of soot particles, which affects their solar absorption efficiency and lifetimes. However, quantifying aging evolution of soot remains hampered in the real world because of complicated sources and observation technologies. In the Himalayas, we isolated soot sourced from transboundary transport of biomass burning and revealed soot aging mechanisms through microscopic observations. Most of coated soot particles stabilized one soot core under Dp &lt; 400 nm, but 34.8% of them contained multi-soot cores (nsoot ≥ 2) and nsoot increased 3–9 times with increasing Dp. We established the soot mixing models to quantify transformation from condensation- to coagulation-dominant regime at Dp ≈ 400 nm. Studies provide essential references for adopting mixing rules and quantifying the optical absorption of soot in atmospheric models.</p

Evaluation of white matter microstructural alterations in premature infants with necrotizing enterocolitis

Background: Preterm infants with necrotizing enterocolitis (NEC) are at high risk of adverse neurodevelopmental outcomes. The aim of this study was to explore the value of diffusion tensor imaging (DTI) combined with serum C-reactive protein (CRP) and procalcitonin (PCT) in evaluating alterations of white matter (WM) microstructure in preterm infants with NEC. Methods: A retrospective cross-sectional study was conducted in which all participants were consecutively enrolled at The Third Affiliated Hospital of Zhengzhou University from June 2017 and October 2021. Data from 30 preterm infants with NEC [mean gestational age at birth 31.41±1.15 weeks; mean age at magnetic resonance imaging (MRI) 37.53±3.08 weeks] and 40 healthy preterm infants with no NEC were recorded (mean gestational age at birth 32.27±2.09 weeks; mean age at MRI 37.15±3.23 weeks). WM was used to obtain the fractional anisotropy (FA) and mean diffusivity (MD) values of the regions of interest (ROIs). Additionally, serum levels of CRP and PCT were determined. Spearman correlation analysis was performed between the WM-derived parameters, CRP level, and the PCT serum index. Results: Preterm infants with NEC had reduced FA values and elevated MD values in WM regions [posterior limbs of the internal capsule (PLIC), lentiform nucleus (LN), frontal white matter (FWM)] compared to the control group (P<0.05). Additionally, the FA of the PLIC was negatively correlated with serum CRP (r=−0.846; P<0.05) and PCT (r=−0.843; P<0.05). Meanwhile, the MD of PLIC was positively correlated with serum CRP (r=0.743; P<0.05) and PCT (r=0.743; P<0.05, respectively). The area under the curve (AUC) of FA and MD combined with CRP and PCT in the diagnosis of WM microstructure alterations with NEC was 0.968, representing a considerable improvement in predicted efficacy over single indicators, including FA [AUC: 0.938; 95% confidence interval (CI): 0.840–0.950], MD (AUC: 0.807; 95% CI: 0.722–0.838), CRP (AUC: 0.867; 95% CI: 0.822–0.889), and PCT (AUC: 0.706; 95% CI: 0.701–0.758). Conclusions: WM can noninvasively and quantitatively assess the WM microstructure alterations in preterm infants with NEC. WM combined with serum CRP and PCT demonstrated superior performance in detecting and evaluating WM microstructure alterations in preterm infants with NEC

A HIGHLY SELECTIVE FLUORESCENT SENSOR FOR DETECTION OF TRIVALENT METAL IONS BASED ON A SIMPLE SCHIFF-BASE

A simple and easily synthesized fluorescent sensor L, based on condensation reaction of 1-Naphthylamine and terephthalaldehyde, was synthesized and characterized systemically. Both UV-vis and fluorescence spectroscopic studies indicated that the sensor L showed good selectivity toward trivalent metal ions (such as Al3+, Fe3+, Cr3+, La3+ and Ce3+) over other monovalent or divalent metal ions. The sensing mechanism was suggested that the trivalent ion promoted the hydrolysis of Schiff base. Meanwhile, took the common trivalent ions Al3+, Fe3+ and Cr3+ as examples, limit of detection (LOD) values of sensor L were calculated to be 1.23, 0.94 and 1.14 nM for Al3+, Cr3+ and Fe3+, respectively, suggesting very high sensitivity towards the cations which could make it attractive in trivalent metal ions detection

A HIGHLY SELECTIVE FLUORESCENT SENSOR FOR DETECTION OF TRIVALENT METAL IONS BASED ON A SIMPLE SCHIFF-BASE

<div><p>A simple and easily synthesized fluorescent sensor L, based on condensation reaction of 1-Naphthylamine and terephthalaldehyde, was synthesized and characterized systemically. Both UV-vis and fluorescence spectroscopic studies indicated that the sensor L showed good selectivity toward trivalent metal ions (such as Al3+, Fe3+, Cr3+, La3+ and Ce3+) over other monovalent or divalent metal ions. The sensing mechanism was suggested that the trivalent ion promoted the hydrolysis of Schiff base. Meanwhile, took the common trivalent ions Al3+, Fe3+ and Cr3+ as examples, limit of detection (LOD) values of sensor L were calculated to be 1.23, 0.94 and 1.14 nM for Al3+, Cr3+ and Fe3+, respectively, suggesting very high sensitivity towards the cations which could make it attractive in trivalent metal ions detection.</p></div

EFFECT OF CALCINATION TEMPERATURE ON THE STRUCTURE AND CATALYTIC PERFORMANCE OF THE CU-MCM-41 CATALYSTS FOR THE SYNTHESIS OF DIMETHYL CARBONATE

A series of Cu-MCM-41 catalysts were synthesized through in-situ hydrothermal preparation method, calcinated at different temperatures and characterized by thermogravimetric and differential scanning calorimetry (TG-DSC), N2 adsorption-desorption, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FI-IR), transmission electron microscopy (TEM) and hydrogen temperature-programmed (H2-TPR). The effect of calcination temperature on the structural properties and selective oxidation of dimethoxymethane (DMM) to dimethyl carbonate (DMC) were discussed in detail. The results showed that the calcination temperature played important role on the microstructure and catalytic activity of the Cu-MCM-41 catalysts. At the calcination temperature 550 °C, the Cu-MCM-41 catalyst possessed higher surface area, smaller pore diameter, stronger metal-support interaction, and better CuO dispersion compared the other catalysts, and the corresponding catalyst exhibited excellent activity and stability for the DMC synthesis. Under the reaction conditions at 2.0 MPa and 130 °C, the highest DMM conversion was 99.47% with the best DMC selectivity of 85.01%. In addition, the catalyst was reused four times without significant loss of performance

Mechanically adaptive nanocomposites with cellulose nanocrystals: Strain-field mapping with digital image correlation

Strain-transfer plays a key role in overall modulus of mechanically adaptive nanomaterials. Herein, mechanically adaptive nanocomposites were prepared via introducing cellulose nanocrystal (CNC) percolating network into poly butyl methacrylate (PBMA) with polyethylene glycol (PEG) as a stabilizer. The prepared PBMA/CNC nanocomposites were soaked in deionized water at 23 °C and 37 °C for one week to investigate their mechanically adaption. The interactions between PEG, CNC, and PBMA were assessed by Fourier Transform infrared, X-ray diffraction, and X-ray photoelectron spectroscopy. Incorporation of PEG to CNC and PBMA/CNC nanocomposites on the morphological and thermal properties was also investigated. The mechanical adaption of PBMA/CNC nanocomposites after switching dry-to-wet state and surrounding temperature (soaked in deionized water at 23 °C and 37 °C for one week, respectively) was evaluated by mechanical testing. Meantime, digital image correlation (DIC) was firstly used to study strain transfer mechanism in mechanical adaption which was carried out in real-time synchronized with mechanical measurement. It indicated that PEG improved the dispersion of CNC in PBMA/CNC nanocomposite and its thermal properties. Furthermore, CNC with PEG modification bridged PBMA during crack propagation and promoted the stress and stain transfer in PBMA/CNC nanocomposites according to DIC analysis