A disordered mesoporous silica was found to be a promising solid support for CO2 capture. It was prepared with a process similar to that for MCM-41. X-ray diffraction characterization (XRD) and ...transmission electron microscopy (TEM) confirmed its disordered structure. N2 adsorption–desorption tests indicated that its average pore size is significantly larger than that of MCM-41. On this support was deposited acrylamide (AM)-modified tetraethylenepentamine (TEPA), resulting in an adsorbent suitable for CO2 capture. This material exhibited well balanced adsorption and desorption properties. Substantially higher CO2 adsorption capacity (159.1 mg/g-adsorbent) was obtained with pure CO2 at 25 °C, and satisfactory stability during 12 adsorption–desorption turnovers was achieved.
Phthalate esters (PAEs) may act as estrogen receptor agonists, and their relationship with precocious puberty is a global health concern. However, their role in isolated premature thelarche (IPT) ...progression remains unclear. We conducted a cohort study investigating the relationship between IPT progression and urinary PAE metabolites. Girls with IPT aged 6-8 years were regularly followed up every three months for one year. Clinical data and urine PAE metabolite levels were collected. Participants who progressed to central precocious puberty (CPP) or early puberty (EP) had significantly higher ovarian volume, breast Tanner stage, and levels of the creatinine-adjusted urinary secondary oxidized di-2-ethylhexyl phthalate (DEHP) metabolites (Σ
DEHP). Breast Tanner stage (odds ratio OR = 7.041, p = 0.010), ovarian volume (OR = 3.603, p = 0.019), and Σ
DEHP (OR = 1.020, p = 0.005) were independent risk factors for IPT progression. For each 10 µg/g/Cr increase in the urine level of Σ
DEHP, the risk of progression from IPT to CPP/EP within one year increased by 20%. This study demonstrated that the breast Tanner stage, ovarian volume, and Σ
DEHP in urine were independent risk factors for IPT progression, and Σ
DEHP may be associated with the progression of IPT to CPP or EP.
Abstract
Estrogen can promote the acceleration of bone maturation and phthalate esters (PAEs) have estrogen-mimicking effects. We investigated whether PAEs are associated with the acceleration of ...bone age (BA) in girls with early onset of puberty (EOP). This case–control study enrolled 254 girls with EOP from the Endocrinology Department at Shenzhen Children’s Hospital between December 2018 and August 2019. Ultra-performance liquid chromatography and tandem mass spectrometry were used to analyze the 10 metabolites of PAEs (mPAEs) in urine samples. BA was measured using an artificial intelligence system. BA exceeding the chronological age (CA) by > 2 years (BA-CA ≥ 2 years) was referred to as significant BA advancement. Participants were divided into groups A (BA-CA ≥ 2 years; case group) and B (BA-CA < 2 years; control group). Propensity score matching (PSM) was performed for both groups in a 1:2 ratio with a caliper of 0.25. To identify potential dose–response relationships between PAEs exposure and BA advancement, we grouped the participants after PSM according to the tertiles of the mPAE concentrations. After PSM, 31 and 62 girls in groups A and B were selected. The concentration of Mono-ethyl phthalate (MEP) in group A was significantly higher than in group B (11.83 μg/g vs. 7.11 μg/g,
P
< 0.05); there was no significant difference in the levels of other mPAEs between the groups. The degree of BA advancement and proportion of significantly advanced BA in the lowest, middle, and highest tertiles of the MEP sequentially increased, as well as in the lowest, middle, and highest tertiles of Mono-(2-ethyl-5-carboxypentyl) phthalate; however, these were only statistically different between the highest and lowest MEP tertiles (both
P
< 0.05). For the remaining mPAEs, differences in the degree of BA advancement among the lowest, middle, and highest tertiles, as well as differences in the proportion of significantly advanced BA among the lowest, middle, and highest tertiles, were not significant (all
P
> 0.05). Our findings suggested that MEP was positively associated with BA advancement in girls with EOP. Exposure to PAEs may promote accelerated bone maturation.
•A secondary amine AN-TEPA is used to modify the SBA-15.•CO2 adsorption capacity (180.1mgg−1-adsorbent for 70% amine loading) is high.•The sorbent exhibits a high stability after 12 cycling runs.•The ...modified SBA-15 achieves complete desorption at low temperature (100°C).
A novel CO2 sorbent was prepared by impregnating mesoporous silica, SBA-15, with acrylonitrile (AN)-modified tetraethylenepentamine (TEPA) in order to increase CO2 adsorption capacity and improve cycling stability. The mesoporous silica with pre- and post-surface modification was investigated by X-ray diffraction characterization (XRD), N2 adsorption–desorption test (N2-BET), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA). The adsorption/desorption performance of S-TN (TN: AN modified TEPA) and S-TEPA was studied by dynamic adsorption. Test results showed that the solid base-impregnated SBA-15 demonstrated high CO2 adsorption capacity (180.1mgg−1-adsorbent for 70% amine loading level). Compared to S-TEPA (24.1% decrease of initial capacity), S-TN with 50% amine loading exhibited improved cycling stability, 99.9% activity reserved (from initial 153.0mgg−1 to 151.3mgg−1) after 12 cycles of adsorption/desorption at 100°C. A mechanism of molecular structure of the loaded amine was attributed to the improved performance.
•Co-doping K/Co at the A/B sites can make the Tc close to room temperature.•K/Co at the A/B sites can improve the magnetocaloric of the samples.•The Tc is increased to 314 K for the samples after K ...substituted.•The LK0.1SMCO has a −ΔSMmax of 4.44 J/(kg K) after K substituted.
We prepared La0.8-xKxSr0.2Mn0.95Co0.05O3 (0 ⩽ x ⩽ 0.1) (LKSMCO) through the modified sol-gel method (S-G) and its structure. Then, the magnetic, magnetocaloric, and critical behavior were analyzed. LKSMCO was confirmed to be the rhombohedral structure within the R-3c space group (No.167) using transmission electron microscopy and X-ray diffraction. For validating the chemical composition of LKSMCO, X-ray photoelectron spectroscopy and EDS were applied, showing that K+ was successfully doped. Phase transition of LKSMCO from paramagnetic to ferromagnetic phase near Curie temperature (Tc) was confirmed with a Magnetic Property Measurement System (MPMS). Using normalization and Banerjee's criterion, LKSMCO was demonstrated to be the second-order magnetic phase transition (SOMPT). As shown from the applied magnetic field, the maximal magnetic entropy (−ΔSMmax) of LKSMCO near Tc was 3.87 J/(kg K) (x= 0.00), 4.28 J/(kg K) (x= 0.05) and 4.44 J/(kg K) (x= 0.10). We employed the Kouvel-Fisher approach (KF) and modified Arrott plots to confirm the values of γ, δ, and β. This indicates that critical exponents of LKSMCO were consistent with the Mean-filed model.
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A disordered mesoporous silica was found to be a promising solid support for CO sub(2) capture. It was prepared with a process similar to that for MCM-41. X-ray diffraction characterization (XRD) and ...transmission electron microscopy (TEM) confirmed its disordered structure. N sub(2) adsorption-desorption tests indicated that its average pore size is significantly larger than that of MCM-41. On this support was deposited acrylamide (AM)-modified tetraethylenepentamine (TEPA), resulting in an adsorbent suitable for CO sub(2) capture. This material exhibited well balanced adsorption and desorption properties. Substantially higher CO sub(2) adsorption capacity (159.1 mg/g-adsorbent) was obtained with pure CO sub(2) at 25 degree C, and satisfactory stability during 12 adsorption-desorption turnovers was achieved.
Graphical abstract: - Highlights: • A secondary amine AN-TEPA is used to modify the SBA-15. • CO{sub 2} adsorption capacity (180.1 mg g{sup −1}-adsorbent for 70% amine loading) is high. • The sorbent ...exhibits a high stability after 12 cycling runs. • The modified SBA-15 achieves complete desorption at low temperature (100 °C). - Abstract: A novel CO{sub 2} sorbent was prepared by impregnating mesoporous silica, SBA-15, with acrylonitrile (AN)-modified tetraethylenepentamine (TEPA) in order to increase CO{sub 2} adsorption capacity and improve cycling stability. The mesoporous silica with pre- and post-surface modification was investigated by X-ray diffraction characterization (XRD), N{sub 2} adsorption–desorption test (N{sub 2}-BET), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA). The adsorption/desorption performance of S-TN (TN: AN modified TEPA) and S-TEPA was studied by dynamic adsorption. Test results showed that the solid base-impregnated SBA-15 demonstrated high CO{sub 2} adsorption capacity (180.1 mg g{sup −1}-adsorbent for 70% amine loading level). Compared to S-TEPA (24.1% decrease of initial capacity), S-TN with 50% amine loading exhibited improved cycling stability, 99.9% activity reserved (from initial 153.0 mg g{sup −1} to 151.3 mg g{sup −1}) after 12 cycles of adsorption/desorption at 100 °C. A mechanism of molecular structure of the loaded amine was attributed to the improved performance.
Plants form a mutualistic symbiosis with arbuscular mycorrhizal (AM) fungi, which facilitates the acquisition of scarce minerals from the soil. In return, the host plants provide sugars and lipids to ...its fungal partner. However, the mechanism by which the AM fungi obtain sugars from the plant has remained elusive.
In this study we investigated the role of potential SWEET family sugar exporters in AM symbiosis in Medicago truncatula.
We show that M. truncatula SWEET1b transporter is strongly upregulated in arbuscule-containing cells compared to roots and localizes to the peri-arbuscular membrane, across which nutrient exchange takes place. Heterologous expression of MtSWEET1b in a yeast hexose transport mutant showed that it mainly transports glucose. Overexpression of MtSWEET1b in M. truncatula roots promoted the growth of intraradical mycelium during AM symbiosis. Surprisingly, two independent Mtsweet1b mutants, which are predicted to produce truncated protein variants impaired in glucose transport, exhibited no significant defects in AM symbiosis. However, arbuscule-specific overexpression of MtSWEET1bY57A/G58D, which are considered to act in a dominant-negative manner, resulted in enhanced collapse of arbuscules.
Taken together, our results reveal a (redundant) role for MtSWEET1b in the transport of glucose across the peri-arbuscular membrane to maintain arbuscules for a healthy mutually beneficial symbiosis.
Although the functions of carotenogenic genes are well documented, little is known about the mechanisms that regulate their expression, especially those genes involved in α- and β-branch carotenoid ...metabolism.
In this study, an R2R3-MYB transcriptional factor (CrMYB68) that directly regulates the transformation of α- and β-branch carotenoids was identified using Green Ougan (MT), a stay-green mutant of Citrus reticulata cv Suavissima. A comprehensive analysis of developing and harvested fruits indicated that reduced expression of β-carotene hydroxylases 2 (CrBCH2) and 9-cis-epoxycarotenoid dioxygenase 5 (CrNCED5) was responsible for the delay in the transformation of α- and β-carotene and the biosynthesis of ABA. Additionally, the expression of these genes was negatively correlated with the expression of CrMYB68 in MT.
Further, electrophoretic mobility shift assays (EMSAs) and dual luciferase assays indicated that CrMYB68 can directly and negatively regulate CrBCH2 and CrNCED5. Moreover, transient overexpression experiments using leaves of Nicotiana benthamiana indicated that CrMYB68 can also negatively regulate NbBCH2 and NbNCED5.
To overcome the difficulty of transgenic validation, we quantified the concentrations of carotenoids and ABA, and gene expression in a revertant of MT. The results of these experiments provide more evidence that CrMYB68 is an important regulator of carotenoid metabolism.
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