Human midbrain dopaminergic progenitors.

Human midbrain dopaminergic progenitors (mDAPs) are one of the most representative cell types in both basic research and clinical applications. However, there are still many challenges for the preparation and quality control of mDAPs, such as the lack of standards. Therefore, the establishment of critical quality attributes and technical specifications for mDAPs is largely needed. "Human midbrain dopaminergic progenitor" jointly drafted and agreed upon by experts from the Chinese Society for Stem Cell Research, is the first guideline for human mDAPs in China. This standard specifies the technical requirements, test methods, inspection rules, instructions for usage, labelling requirements, packaging requirements, storage requirements, transportation requirements and waste disposal requirements for human mDAPs, which is applicable to the quality control for human mDAPs. It was originally released by the China Society for Cell Biology on 30 August 2022. We hope that the publication of this guideline will facilitate the institutional establishment, acceptance and execution of proper protocols, and accelerate the international standardization of human mDAPs for clinical development and therapeutic applications.

Gestational cadmium exposure disrupts fetal liver development via repressing estrogen biosynthesis in placental trophoblasts.

Cadmium (Cd), commonly found in diet and drinking water, is known to be harmful to the human liver. Nevertheless, the effects and mechanisms of gestational Cd exposure on fetal liver development remain unclear. Here, we reported that gestational Cd (150 mg/L) exposure obviously downregulated the expression of critical proteins including PCNA, Ki67 and VEGF-A in proliferation and angiogenesis in fetal livers, and lowered the estradiol concentration in fetal livers and placentae. Maternal estradiol supplement alleviated aforesaid impairments in fetal livers. Our data showed that the levels of pivotal estrogen synthases, such as CYP17A1 and 17ß-HSD, was markedly decreased in Cd-stimulated placentae but not fetal livers. Ground on ovariectomy (OVX), we found that maternal ovarian-derived estradiol had no major effects on Cd-impaired development in fetal liver. In addition, Cd exposure activated placental PERK signaling, and inhibited PERK activity could up-regulated the expressions of CYP17A1 and 17ß-HSD in placental trophoblasts. Collectively, gestational Cd exposure inhibited placenta-derived estrogen synthesis via activating PERK signaling, and therefore impaired fetal liver development. This study suggests a protective role for placenta-derived estradiol in fetal liver dysplasia shaped by toxicants, and provides a theoretical basis for toxicants to impede fetal liver development by disrupting the placenta-fetal-liver axis.

[Heavy Metal Content of Rural Living Solid Waste and Related Source and Distribution Analysis].

Living solid waste of 72 typical villages and towns in 12 provinces was investigated, and related heavy metal pollution characteristics, source, and distribution were analyzed. Results showed that heavy metal content of As, Hg, Pb, Cd, Cr, Cu, Zn, and Ni in living solid waste of typical northern villages of China was (7.51±8.89), (0.64±0.42), (21.91±12.29), (4.82±8.37), (86.36±59.99), (36.43±15.98), (62.19±36.61), and (46.07±25.22) mg·kg-1, respectively. Content of As, Hg, Pb, Cd, Cr, Cu, Zn, and Ni in living solid waste of typical southern towns was (7.43±8.82), (0.83±0.74), (21.62±13.76), (1.84±4.55), (131.06±74.96), (37.20±16.80), (98.04±63.71), and (46.75±25.75) mg·kg-1, respectively. Cd and Hg exceeded the standards for urban garbage agricultural control and soil environmental quality. Sources of heavy metals in domestic waste were explored by Pearson correlation analysis, cluster analysis, and principal component analysis. Results showed that Pb and Cd were mainly derived from kitchen waste, dust, paper, rubber, and plastic. Hg was mainly from kitchen waste and dust. Zn and Cr were mainly from dust. Cu was mainly from dust, paper, rubber, plastic, battery, and electronic waste. Ni was mainly from battery and electronic wastes. As was mainly derived from pesticides and fertilizers.

Modification of chitin with high adsorption capacity for methylene blue removal.

Porous chitin sorbents (PChs) with different content of chitin, ranging from 0.9% to 3.5%, were prepared by gel method with CaBr2·xH2O/CH3OH solution and characterized by FT-IR, XRD and SEM. The adsorption isotherms and kinetic analysis of methylene blue (MB) onto PChs were studied. Experimental results illustrated lower crystallinity and more pores of PChs containing 3.5% chitin displayed higher adsorption capacity, the removal of MB was 79.8%. The adsorption equilibrium isotherm curve of MB onto PChs adsorbents conformed to the Freundlich equation. The PFO, PSO and Weber-Morris models were applied to fit with the adsorption kinetics. The results demonstrated the adsorption of MB might be the mass transfer of heterogeneous system and involve multiple diffusion steps. The adsorption capacity of PChs with 3.5% chitin can maintain 65% removal ratio of MB after being used six adsorption-desorption cycles. It was supposed that PChs may be a promising, cheap, environmentally friendly and efficient adsorbent for some dye wastewater treatment in the near future.

Observation on the ion association equilibria in NaNO3 droplets using micro-Raman spectroscopy.

Ion association ratios as a function of concentration were estimated in single NaNO(3) droplets (5-60 µm) on a polytetrafluoroethylene (PTFE) substrate with molar water-to-solute ratios (WSRs) of 0.8-28 and bulk NaNO(3) solutions with WSRs of 35-200 by combining micro-Raman spectroscopy and component band analysis. Concentrations of the NaNO(3) droplets were accurately controlled by adjusting relative humidity (RH) in a sample chamber. As the WSRs decreased from 200 to 0.8, symmetric stretching band (ν(1)-NO(3)(-)) was observed to shift from 1047 to 1058 cm(-1) along with a change in full width at half-maximum (fwhm) from ∼10 to ∼16 cm(-1), indicative of formation of ion pairs with different structures. Through the component band analysis of the ν(1)-NO(3)(-) band, five bands centered at 1040.0, 1042.9, 1048.5, 1053.5, and 1057.0 cm(-1) were identified and assigned to coupled wagging modes of water molecules hydrated with nitrate ions, free hydrated nitrate anions, solvent-shared ion pairs (SIPs), contact ion pairs (CIPs), and the complex ion aggregates (CIAs), respectively. There were large amounts of SIPs and CIPs in dilute NaNO(3) solution even at an extremely low concentration (WSR ∼ 200), and each accounted for 50% and 20% of total nitrate species, respectively. This finding is in good agreement with earlier reported observations. In the dilute solutions (45 < WSR < 200), there is the same amount of free hydrated ions transformed into SIPs as that of SIPs transformed into CIPs. As a result, the overall amount of SIPs remained unchanged over the concentration range. With a decrease in WSR from 45 to 0.8, the amounts of SIPs and free solvated NO(3)(-) ions kept decreasing, whereas the amount of CIPs rose to a maximum at WSR = 7 and then fell with a further decreasing WSR. Formation of CIAs started at WSR ∼ 45, and its amount continuously increased as the WSR is further reduced to 0.8. The effect of temperature on ion association structure in the NaNO(3) droplets was also studied in the present work. An increase in temperature promoted formation of both CIPs and CIAs, and the latter was more pronounced. At 80 °C, the most concentrated NaNO(3) droplets had a WSR approximately equal to 0.12 and were in amorphous state with cations and anions aggregated in a complicated manner, highly similar to ionic liquid.

Suppression of NaNO3 crystal nucleation by glycerol: micro-Raman observation on the efflorescence process of mixed glycerol/NaNO3/water droplets.

Although the hygroscopicity of a NaNO(3)/water microdroplet and a polyalcohol/water microdroplet, two of the most important aerosols in atmosphere, has been widely studied, little is known about the relationship between the hygroscopic behavior of mixed NaNO(3)/polyalcohol/water droplets and their structures on the molecular level. In this study, the hygroscopicity of mixed glycerol/NaNO(3)/water droplets deposited on a hydrophobic substrate was studied by micro-Raman spectroscopy with organic-to-inorganic molar ratios (OIRs) of 0.5, 1, and 2. In the mixed glycerol/NaNO(3)/water droplets, glycerol molecules tended to combine with Na(+) and NO(3)(-) ions by electrostatic interaction and hydrogen bonding, respectively. On the basis of the analyses of the changes of symmetric stretching (v(s)-CH(2)), asymmetric stretching (v(a)-CH(2)), their area ratio (Av(a)-CH(2)/Av(s)-CH(2)) of glycerol, and symmetric stretching band of NO(3)(-) (ν(1)-NO(3)(-)) with relative humidity (RH), it was found that the conformation of glycerol was transformed from αα mainly to γγ and partly to αγ with a decreasing RH in the mixed droplets, contrary to the case in the glycerol/water droplet. In addition, the glycerol with γγ and αγ conformation had strong interaction with Na(+) and NO(3)(-) respectively, which suppressed the formation of contact of ions and delayed the efflorescence relative humidity (ERH) for the mixed droplets compared to the NaNO(3)/water droplet.

Observation of conformational changes in 1-propanol-water complexes by FTIR spectroscopy.

Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) measurements were carried out on the 1-propanol-water (abbreviated as 1PA-W) mixtures over the entire 1-propanol molar fraction range at 298 K. The two bands at approximately 1053 and approximately 1068 cm(-1), assigned to the vibrational modes of the gauche (v(C-C-C-O-G)) and the trans (v(C-C-C-O-T)) conformational isomers, respectively, which both include C-O and C-C stretching motions, were used to monitor the structural changes of the mixtures. When the water to 1-propanol molar ratio (WPR) is smaller than 0.2, the absorbance ratio of the two bands (A(vC-C-C-O-G)/A(vC-C-C-O-T)) remains constant at 1.42, characteristic of the existence of the 1-propanol aggregate chains, hydrogen-bonded by the O-H groups of 1-propanol in gauche conformations. When increasing the WPR from 0.2 to 20, there is an abrupt decrease in the absorbance ratio (A(vC-C-C-O-G)/A(vC-C-C-O-T)) from 1.42 to 1.01, corresponding to penetration of water molecules into the gauche-aggregate chains. The penetrated water molecules disrupt the 1PA chains and transform these gauche-aggregate 1PA chains to trans-aggregate chains, which are 1PA dimers of trans-conformation. The structural change induces complicated spectroscopic changes, including the red shifts of the series of bands 1016, 1053, and 1098 cm(-1) and blue shifts of the bands 2877, 2937, and 2961 cm(-1). With further increase of WPR up to 100, the absorbance ratio of A(vC-C-C-O-G)/A(vC-C-C-O-T) increases from 0.98 to 1.07, indicating a transformation of partial 1PA dimers to single molecules with gauche-conformation in the water hydrogen-bonding network. Together with results from quantum calculations at the B3L YP/6-31G (d, p) level, and two-dimensional infrared correlation and excess spectroscopy analysis, the structural evolution of water and 1PA molecules in 1PA-W mixtures has been inferred.