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Circularly polarized light (CPL) detection has sparked the booming interest for versatile chiral-optoelectronic and spintronic devices. For practical device applications, a large asymmetry factor is required to distinguish the handedness of incent light. However, for most chiral CPL active candidates, the difference in optical density or absorption anisotropy is quite subtle under CPL illumination, resulting in a relatively low asymmetry factor (usually ≤ 0.2). Up to date, it remains extremely challenging to achieve CPL response in the achiral crystals. Inch-size achiral perovskite-type crystals of (IBA)2(EA)2Pb3I10 (IBA = 4-isopropylbenzylammonium, EA = ethylammonium), which holds a promise to distinguish CPL with a large asymmetry factor up to ≈0.56 at 405 nm is presented here. This figure-of-merit is comparable or even superior than most of those chiral counterparts. Further First-principles calculations disclose such CPL-active behaviors of (IBA)2(EA)2Pb3I10 are associated with the splitting of its band spin-degeneracy, induced by the breaking of inversion symmetry and spin-orbital coupling (SOC) effects. As far as it is known, the structural origin of CPL-activities of (IBA)2(EA)2Pb3I10 is completely distinctive from the conventional chiral family, which paves a promising pathway to explore new candidates toward high-performance CPL detection. [ABSTRACT FROM AUTHOR]

The interactions between polymer molecules in solution are strongly affected by the way that the constituent polymers interact with the solvent. In this work, we use a mixed solvent system (dimethyl sulfoxide and ethylene glycol) to tailor the strength of the hydrogen-bonding interactions between partially quaternized poly(4-vinylpyridine) [QVP] and poly(methacrylic acid) [PMAA]. The charge introduced by the quaternization reaction enables homogeneous solutions to be formed over a large concentration range, even in the presence of attractive hydrogen-bonding interactions between the proton-donating PMAA and the proton-accepting QVP. The viscoelastic properties of equimolar QVP/PMAA solutions are superposed onto master curves that are well-described by a fractional Maxwell liquid model. This model provides a means for quantifying the dependence of the relaxation times on the solvent composition. These relaxation times increase by a factor of 1000 as the hydrogen-bonding interactions are strengthened by a decrease in the DMSO content of the solvent, within a composition regime where the solutions remain homogeneous. A much stronger effect is obtained when the ethylene glycol is replaced by water. [ABSTRACT FROM AUTHOR]

Poly(methyl methacrylate)-poly(methacrylic acid)-poly(methyl methacrylate) (PMMA-PMAA-PMMA) triblock copolymers can self-assemble into well-defined elastic hydrogels in water by forming glassy PMMA micelle cores connected with PMAA bridges. The stiffness and toughness of these hydrogels are enhanced substantially by introducing partially quaternized poly(4-vinylpyridine) (QVP) into the system. Interactions between the QVP and PMAA molecules provide an energy dissipation mechanism, with fracture energies in excess of 1000 J/m² obtained in some cases. The materials are fully self-assembled and are formed by exposing liquid solutions in DMSO to small amounts of water. The simplicity of gel formation, and the ability to adjust the chemical and physical characteristics of these materials over a wide range, make them excellent model systems for fundamental investigations of the mechanical response of ion-containing gels. [ABSTRACT FROM AUTHOR]

Passivation of electrode surface and tedious reconstruction of biosensing architectures have long plagued researchers for the development of electrochemical biosensors. Here, we report a novel self-cleaning electrode by modifying the commonly used working electrode with superhydrophobic and conductive nanocomposite. Owing to the superhydrophobicity and the chemical stability, the electrode avoids passivation result from both adsorption of molecules and oxidation in air. The high conductivity and the high effective area also allow the achievement of enhanced electrochemical signals. On the basis of comprehensive studies on this novel electrode, we have applied it in the fabrication of refreshable electrochemical biosensors for both electro-active and electro-inactive targets. For both cases, detection of the targets can be well performed, and the self-cleaning electrode can be refreshed by simply washing and applied for successive measurements in a long period. [ABSTRACT FROM AUTHOR]

Graphene/zinc ferrite/polyaniline (GE/ZnFe2O4/PANI) composites, a kind of attractive photocatalytic inorganic antibacterial agent, were prepared via the in-situ polymerization and characterized by the modern test technologies. The antibacterial properties of the samples were investigated against Staphylococcus aureus, Escherichia coli and Candida albicans under daylight. The results showed the antibacterial activity of the sample was influenced by strain and the mass ratio of PANI to GE/ZnFe2O4 (mP/GZ) in the GE/ZnFe2O4/PANI composite. In which, the sample with mP/GZ of 0.6 had the best antibacterial activity, and its minimal inhibitory concentration is 12.5µg/mL for Candida albicans. Moreover, the antibacterial mechanisms were discussed. [ABSTRACT FROM AUTHOR]

Some organisms have a remarkable ability to heal wounds without scars and to regenerate complex tissues following injury. By gaining a more complete understanding of the biological mechanisms that promote scar-free healing and tissue regeneration, it is hoped that novel treatments that can enhance the healing and regenerative capacity of human patients can be found. In the present article, we briefly examine the genetic, molecular and cellular mechanisms underlying the regeneration of the Xenopus tadpole tail. [ABSTRACT FROM AUTHOR]

Bacterial keratitis can lead to intraocular infection and even blindness without prompt and potent treatments. Currently, clinical abuse of antibiotics encouraged the evolution of resistant bacteria. Conventional antibiotic eye drops based keratitis treatment has been heavily restricted due to the lack of bactericidal efficiency and easy induction of bacterial resistance. Hence, developing an effective treatment strategy for bacterial keratitis is of great significance. In this work, we investigated ε-poly-L-lysine (EPL)-modified polydopamine (PDA) nanoparticles (EPL@PDA NPs)-mediated antibacterial photothermal therapy (aPTT), to cope with methicillin-resistant Staphylococcus aureus (MRSA)-induced keratitis. The surface modification of cationic peptide EPL enables EPL@PDA NPs to specifically target negatively charged MRSA and induces local hyperthermia to kill the bacteria under low ambient temperature. Under nearinfrared (NIR) irradiation, the sterilization efficiency of EPL@PDA NPs suspension for MRSA in vitro was up to 99.96%. The EPL@PDA-mediated aPTT presented potent antibacterial efficacy in treating MRSA-induced keratitis with little corneal epithelial cytotoxicity and good biocompatibility. In conclusion, the bacterial-targeting aPTT platform in this work provides a prospective method for the management of MRSAinduced refractory bacterial keratitis. [ABSTRACT FROM AUTHOR]

To limit the spread of severe acute respiratory syndrome coronavirus 2, the government of China has been monitoring infected travelers and minimizing cold-chain contamination. However, other factors might contribute to recurring outbreaks. We analyze the role of undocumented migrants as potential transmitters of severe acute respiratory syndrome coronavirus 2 in China. [ABSTRACT FROM AUTHOR]

X-ray repair cross-complementing group 1 (Xrcc1), a key DNA repair gene, plays a vital role in maintaining genomic stability and is highly expressed in the early stages of spermatogenesis, but the exact functions remain elusive. Here we generated primordial germ cell-specific Xrcc1 knockout (cXrcc1-/-) mice to elucidate the effects of Xrcc1 on spermatogenesis. We demonstrated that Xrcc1 deficiency results in infertility in male mice due to impaired spermatogenesis. We found that cXrcc1-/- mice exhibited smaller size of testes as well as lower sperm concentration and motility than the wild-type mice. Mechanistically, we demonstrated that Xrcc1 deficiency in primordial germ cells induced elevated levels of reactive oxygen species, mitochondria dysfunction, apoptosis, and loss of stemness of spermatogonial stem cells (SSCs) in testes. In Xrcc1-deficienct SSCs, elevated oxidative stress and mitochondrial dysfunction could be partially reversed by treatment with the antioxidant N-acetylcysteine (NAC), whereas NAC treatment did not restore the fertility or ameliorate the apoptosis caused by loss of Xrcc1. Overall, our findings provided new insights into understanding the crucial role of Xrcc1 during spermatogenesis. [ABSTRACT FROM AUTHOR]

Mesenchymal stem/stromal cells (MSCs) derived from placental tissue show great therapeutic potential and have been used in medical treatment, but the similarity and differences between the MSCs derived from various parts of the placenta remain unclear. In this study, we compared MSCs derived from different perinatal tissues, including the umbilical cord (UC), amniotic membrane (AM), chorionic plate (CP) and decidua parietalis (DP). Using human leukocyte antigen (HLA) typing and karyotype analysis, we found that the first three cell types were derived from the foetus, while the MSCs from the decidua parietalis were derived from the maternal portion of the placental tissue. Our results indicate that both foetal and maternal MSCs share a similar phenotype and multi-lineage differentiation potential, but foetal MSCs show a significantly higher expansion capacity than do maternal MSCs. Furthermore, MSCs from all sources showed significant differences in the levels of several paracrine factors. [ABSTRACT FROM AUTHOR]

An iron-catalyzed reaction of pyridine and a-substituted allenoate has been disclosed. The present strategy incorporates the aerobic oxidation into annulation involving substituted allenoate, thus providing a new access to functionalized indolizine. [ABSTRACT FROM AUTHOR]

The long non-coding RNA (lncRNA) H19 as an imprinted gene transcribed from only the maternal allele has the vital role in carcinogenesis. Aberrant H19 expression is involved in bladder cancer development. In this study, we explored the association between single nucleotide polymorphisms (SNPs) in H19 and bladder cancer risk. Four tagging SNPs (tagSNPs) were selected from the 1000 Genomes Project database. In total, 1049 bladder cancer cases and 1399 controls were recruited in this case-control study. Odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were calculated by using unconditional univariate and multivariate logistic regression models to evaluate associations between the H19 tagSNPs genotypes and risk of bladder cancer. We found a statistically significant increased risk of bladder cancer in the carriers of the rs217727 AA genotype compared with carriers of GG/GA genotype (OR = 1.31, 95% CI = 1.03-1.67). The subsequently stratified analyses also revealed that the H19 rs217727 AA genotype remarkably elevated the risk of bladder cancer in subgroups of young subjects (OR = 1.80, 95% CI = 1.16-2.81), males (OR = 1.44, 95% CI = 1.10-1.89) and smokers (OR = 1.55, 95% CI = 1.06-2.27), as well as high tumour grade (OR = 1.89, 95% CI = 1.23-2.91) and invasive disease (OR = 1.62, 95% CI = 1.01-2.60). This finding indicates that the rs217727 polymorphism is significantly associated with the risk of bladder cancer. [ABSTRACT FROM AUTHOR]

Nicotinamide adenine dinucleotide phosphate (NADP) is a critical cofactor during metabolism, calcium signaling, and oxidative defense, yet how animals regulate their NADP pools in vivo and how NADP-synthesizing enzymes are regulated have long remained unknown. Here we show that expression of Nadk, an NAD+ kinase-encoding gene, governs NADP biosynthesis in vivo and is essential for development in Xenopus frog embryos. Unexpectedly, we found that embryonic Nadk expression is dynamic, showing cell type-specific up-regulation during both frog and sea urchin embryogenesis. We analyzed the NAD kinases (NADKs) of a variety of deuterostome animals, finding two conserved internal domains forming a catalytic core but a highly divergent N terminus. One type of N terminus (found in basal species such as the sea urchin)mediates direct catalytic activation of NADK by Ca2+/calmodulin (CaM), whereas the other (typical for vertebrates) is phosphorylated by a CaM kinase-dependent mechanism. This work indicates that animal NADKs govern NADP biosynthesis in vivo and are regulated by evolutionarily divergent and conserved CaM-dependent mechanisms. [ABSTRACT FROM AUTHOR]

Polymeric materials as anion exchange membranes (AEMs) play an essential role in the field of energy and environment. The achievement of high performance AEMs by the precise manipulation of macromolecular architecture remains a daunting challenge. Herein, we firstly report a novel rod-coil graft copolymer AEM, possessing rigid hydrophobic main chains and soft hydrophilic graft chains. The low graft density, which can alleviate the adverse influences of ioinc graft chains on the main chains, was obtained by using the living polymerization technique. Consequently, the grafted ionic groups which result in the degradation of polymer backbone was decreased to a small degree. Moreover, the relatively long graft chains induced the nanophase separation between the hydrophobic polymer chains and hydrophilic graft chains, which creates a convinient pathway for high hydroxide ion mobility. Such an accurate molecular design simultaneously improves the hydroxide ion conductivity and alkaline stability as well as dimensional stability. [ABSTRACT FROM AUTHOR]

The molecular mechanisms underlying the formation of neurons with defined neurotransmitters are not well understood. In this study, we demonstrate that the PcG-like genes in Caenorhabditis elegans, sop-2 and sor-3, regulate the formation of dopaminergic and serotonergic neurons and several other neuronal properties. sor-3 encodes a novel protein containing an MBT repeat, a domain that contains histone-binding activity and is present in PcG proteins SCM and Sfmbt in other organisms. We further show that mutations in sor-3 lead to ectopic expression of Hox genes and cause homeotic transformations. Specification of certain neuronal identities by these PcG-Iike genes appears to involve regulation of non-Hox gene targets. Our studies revealed that the PcG-like genes are crucial for coordinately regulating the expression of discrete aspects of neuronal identities in C. elegans. [ABSTRACT FROM AUTHOR]