Cellulose Nanofiber-Based Nanocomposite Films with Efficient Electromagnetic Interference Shielding and Fire-Resistant Performance.

Cellulose nanofiber (CNF) has been widely used as a flexible and lightweight polymer matrix for electromagnetic shielding and thermally conductive composite films because of its excellent mechanical strength, environmental performance, and low cost. However, the lack of flame retardancy seriously hinders its further application. Herein, renewable and biomass-sourced l-arginine (AR) was used to surface-modify ammonium polyphosphate (APP) and an environmentally friendly biobased flame retardant was synthesized by the coordination of zinc sulfate heptahydrate (ZnSO4·7H2O), which was named AAZ. AAZ was deposited on the surface of CNF by electrostatic adsorption and Zn2+ complexation. The biobased compatibilizer Triton X-100 was employed to assist the exfoliation of graphene nanoplatelets (GNPs) and their dispersion in the CNF matrix. Due to the formation of a dense lamellar layer resembling a shell structure, the CNF/GNPs composite films with a tensile strength of 52 MPa were obtained via vacuum-assisted filtration. Because the phosphorus-containing group produces a protective layer of PxOy compound and promotes the formation of a carbon layer by CNF and the combustion releases ammonia gas, the fire-resistant performance of the composite films was greatly improved. Compared with the pure CNF film, the composite film exhibits 33% reduction in PHRR value and 40% reduction in THR. In addition, the CNF/GNPs composite film with 20 wt % GNPs possessed high conductivity (2079.2 S/m) and electromagnetic interference (EMI) shielding effectiveness (37 dB). The ultrathin CNF/GNPs composite films have excellent potential for use as efficient flame retardant and EMI shielding materials.

Regulating the PO4 and TiO6 Polyhedral Building Blocks in TiP2O7 Boosts the Potassium Ion Diffusion Kinetics.

Achieving fast and durable potassiation/depotassiation of anode materials for potassium ion batteries (PIB) still remains an elusive yet fascinating goal. Herein, we challenge the conventional wisdom in synthesizing the TiP2O7 superstructure and report a nanocarbon coating on TiP2O7 (TiP2O7/C) using layered MXene as a Ti source to realize an effective tuning in the TiO6 and PO4 building blocks for boosting the K+ diffusion kinetics in PIB. Experimental investigations coupled with systematic theoretical simulations indicate that the interface interaction between TiP2O7 and coated nanocarbon could induce internal adjustment in individual Ti-O bonding and relieve the local distortions of TiO6 octahedra, which endows the TiP2O7/C with favorable regulation in a K+ hopping manner and significantly reduces the K+ diffusion barrier via the diffusion propagation along PO4 blocks with dominant coordination between O/P and K+. Consequently, the TiP2O7/C anode could retain 230 mA h g-1 even after 2200 long-term cycles with an ultralow degradation rate of 0.005%.

A novel CT-responsive hydrogel for the construction of an organ simulation phantom for the repeatability and stability study of radiomic features.

Radiomic features have demonstrated reliable outcomes in tumor grading and detecting precancerous lesions in medical imaging analysis. However, the repeatability and stability of these features have faced criticism. In this study, we aim to enhance the repeatability and stability of radiomic features by introducing a novel CT-responsive hydrogel material. The newly developed CT-responsive hydrogel, mineralized by in situ metal ions, exhibits exceptional repeatability, stability, and uniformity. Moreover, by adjusting the concentration of metal ions, it achieves remarkable CT similarity comparable to that of human organs on CT scans. To create a phantom, the hydrogel was molded into a universal model, displaying controllable CT values ranging from 53 HU to 58 HU, akin to human liver tissue. Subsequently, 1218 radiomic features were extracted from the CT-responsive hydrogel organ simulation phantom. Impressively, 85-97.2% of the extracted features exhibited good repeatability and stability during coefficient of variability analysis. This finding emphasizes the potential of CT-responsive hydrogel in consistently extracting the same features, providing a novel approach to address the issue of repeatability in radiomic features.

Simply and Cheaply Prepared Liposomal Membrane for Nanocarriers: High Encapsulation Efficiency Based on Broad Regulation of Surface Charges and pH-Switchable Performance.

The zeta potential of nanoparticles impacts their distribution and metabolism in the body as well as their interaction with medications of varying charges, hence altering therapeutic efficacy and safety. In this paper, the external charges of liposomes were regulated by utilizing a simple and economical method based on competition for protons of cationic chitosan (CS) and anion hyaluronic acid (HA). The charge regulation of a liposomal membrane is generally accomplished by adjusting the ratio of charged lipids within a liposome (e.g., cationic DOTAP or anionic DOPS), the stability of which was maintained by the coating materials of cationic chitosan (CS) or anion hyaluronic acid (HA). A series of nanoparticles could respond to pH-stimulation with adjustable surface charge. Moreover, the sizes of liposomes coated with CS and HA remain within a narrow range. In vitro cytotoxicity tests revealed that the nanocarriers were safe, and the nanoparticles containing antitumor medicines were efficient in tumor therapy. Considering liposomes with different external surface charges could be aimed at diverse therapy purposes. The strategies for regulating liposomal surface charges with high encapsulation rates and certain release cycles reported here could provide a versatile platform as carriers for the delivery of drugs and other macromolecules into human bodies.

Toward flame-retardant and toughened poly(lactic acid)/cross-linked polyurethane blends via the interfacial reaction with the modified bio-based flame retardants.

Incorporating bio-based flame retardants into polylactic acid (PLLA) to improve flame retardancy has always been the focus of research, but the improvement of flame retardancy is usually at the expense of mechanical properties. How to successfully balanced the material's mechanical and combustion properties has puzzled many scholars. Herein, ammonium polyphosphate (APP) and chitosan (CS) were used as acid source and carbon source respectively. Biological flame retardant APP@CS was designed and synthesized by electrostatic self-assembly method. In addition, toughened PLLA composites were prepared by reactive blending with the in-situ formed polyurethane (PU) as toughening phase. The results show that the CS shell not only reduces the hydrophilicity of the flame retardant, but also has good flame retardant property because of its excellent char forming property. The addition of 10 phr APP@CS can endow PLLA/crosslinked PU (CPU) with UL-94 V-2 rating and a LOI value of 24.9 %. Interestingly, CS shell participates in the in-situ reaction, which improves the mechanical properties of the composite with elongation at break of 74 %, which is higher than that of sample doped with the same amount of APP. This work provides guidance for the high performance modification of PLLA and is expected to expand the practical application range.

The menstrual cycle regularity and skin: irregular menstrual cycle affects skin physiological properties and skin bacterial microbiome in urban Chinese women.

BACKGROUND: The regularity of the menstrual cycle directly affects women's health. Many studies have focused on menstrual health; however, menstrual cycle regularity-related variations in skin physiological characteristics and skin microbiota have been seldom investigated. METHODS: To investigate the menstrual cycle regularity-related variations in skin physiological characteristics and skin microbiota of 197 cases of Chinese women aged 18-35 years living in shanghai in 2021. Based on a self-evaluation questionnaire, the volunteers were divided into three groups C1 (those with a regular menstrual cycle), C2 (those with a less regular menstrual cycle) and C3 (those with an irregular menstrual cycle). The physiological parameters of facial skin were measured by non-invasive methods and the skin microbiome was analyzed by 16S rRNA high-throughput sequencing. RESULTS: In the C3 group, the hydration content was significantly decreased (p < 0.05), the TEWL was significantly increased (p < 0.05), and the sebum content was increased (p > 0.05), indicating that the skin barrier integrity weakened with increased menstrual cycle irregularity. Additionally, the melanin level, L value and b value were significantly decreased (p < 0.05) in the C3 group, but the a value was significantly increased (p < 0.001), which indicated that the skin color became darker. Furthermore, the skin microbiota diversity decreased with increasing cycle irregularity, but the differences were not significant. The skin microbiota composition showed that the proportion of Firmicutes, Acinetobacter, Staphylococcus and Cutibacterium were increased in those with an irregular menstrual cycle, indicating that alterations in the ratio of bacterial phyla and/or genera might disturb skin homeostasis. Spearman correlation analysis revealed strong correlations between the microbiota and skin physiological parameters. Based on the associations among hormones, skin physiological parameters and skin microbiota, it is possible that the skin physiological parameters, as well as the skin microbial diversity and composition, change with hormonal fluctuations during the menstrual cycle. CONCLUSIONS: An irregular menstrual cycle can affect skin physiological characteristics and the skin microbiota. Female with an irregular menstrual cycle should strengthen skin care practices and use skin care products with moisturising and soothing effects to protect their skin.

Controllable chiral inversion via thioether bond-activated J- and H-aggregation transformation.

Herein, thioether bonds in the peripheral groups of chiral dendrimer that could activate the transformation between J- and H-aggregation in π-systems and caused controllable chiral inversion are described. Furthermore, owing to the close-knit per-aggregation of dendrimers impeding the transfer of inherent molecular chirality, the inversed chirality could be memorized and transferred from oligomers to nano-helices during self-assembly.

Modulus watch: In situ determination of the gel modulus by timing the fluorescence color change.

The gel modulus, a key parameter for gel materials, is traditionally determined by cumbersome rheometer. Recently, probe technologies occur to meet the requirements of in situ determination. Till now, in situ and quantitatively testing of gel materials with unabridged structure informations still remains a challenge. Here, we provide a facile, in situ approach to determine the gel modulus, by timing the aggregation of a doped fluorescence probe. The probe shows green emission during aggregation and shifts to blue once it forms aggregates. The higher modulus of the gel, the longer probe's aggregation time. Furthermore, a quantitative correlation of gel modulus with the aggregation time is established. The in situ method not only facilitates the scientific researches in the field of gels, but also provides a new approach for spatiotemporal materials.

Synergistic Effect of Two Plasticizers on Thermal Stability, Transparency, and Migration Resistance of Zinc Arginine Stabilized PVC.

The effect of different plasticizers on thermal stability, transparency, and migration resistance of the PVC stabilized with zinc arginine [Zn(Arg)2] was investigated. The thermal stability, migration resistance, and transparency of PVC with tributyl citrate (TBC) were better than PVC with dioctyl phthalate (DOP) characterized by oven aging method, migration test, and near infrared-visible-ultraviolet spectrophotometer. At the same time, the longer the carbon chain in citric acid esters, the better the thermal stability and transparency of PVC sample. The hydroxyl group in citric acid esters is helpful to improve the thermal stability of PVC samples. However, the elongation at break and Tg value of PVC containing DOP were very close to those of PVC containing TBC. The calculation results of Hansen solubility parameters also illustrated that DOP had better compatibility with PVC than TBC. Therefore, the excellent transparency and thermal stability of TBC plasticized PVC were attributed to the good compatibility between TBC and Zn(Arg)2, which was verified by the solubility test. Lastly, the mixture of dioctyl terephthalate (DOTP) and TBC was used as plasticizers for Zn(Arg)2 stabilized PVC. When the ratio of TBC and DOTP was 1:1, the transparency, thermal stability, and migration resistance of Zn(Arg)2 stabilized PVC samples were better than those of PVC plasticized by DOP or TBC alone. The mechanism was that the compatibility between Zn(Arg)2 and PVC was greatly improved by the synergetic effect of TBC and DOTP, resulting in the improvement of thermal stability, migration resistance, and transparency of PVC samples.

A true color palette: binary metastable photonic pigments.

Different from the traditional concept that binary photonic crystals can only reproduce mixed colors due to the simple superposition of the photonic band gaps, precisely addressable "true colors" obtained from volume fraction deviation of binary photonic crystals with metastable structures are reported here. Inspired by the mussels' adhesion and longhorn beetles' photonic scales, a binary metastable amorphous photonic crystal was obtained by enhancing the driving forces and customizing the surface roughness of building blocks to regulate the thermodynamic and dynamic factors simultaneously. By controlling the volume fraction of two building blocks, the tunable photonic bandgap varies linearly in the visible region. Furthermore, the "true violet" that cannot be obtained by conventional color mixing is reproduced with the particular ultraviolet characteristics of red photonic pigment's metastable structures, which complement the palette effect of "true colors". Meanwhile, due to the self-adhesion and post-modification of building blocks, the stability of photonic pigments is further improved. The binary photonic pigments not only solve the dilemma of mixed colors, but also realize the tunability and multiplicity of "true colors", offering a new choice for the color palette of the world.

Regular Late Bedtime Significantly Affects the Skin Physiological Characteristics and Skin Bacterial Microbiome.

Background: Late bedtime is a common form of unhealthy sleep pattern in adulthood, which influences circadian rhythm, and negatively affects health. However, little is known about the effect of regular late bedtime on skin characteristics, particularly on skin microbiome. Objective: To investigate the changes and effects of the regular late bedtime on skin physiological parameters and facial bacterial microbiome of 219 cases of Chinese women aged 18-38 years living in Shanghai. Methods: Based on the Self-Evaluation Questionnaire, bedtime was categorized as 11:00 PM; thus, the volunteers were divided into early bedtime group (S0) and late bedtime group (S1). The physiological parameters of facial skin were measured by non-invasive instrumental methods, and the skin microbiome was analyzed by 16S rRNA high-throughput sequencing. Results: The skin physiological parameters of the late bedtime group exhibited significant decrease in skin hydration content, skin firmness (F4) and elasticity (R2), while TEWL, sebum and wrinkle significantly increased. The result indicated that late bedtime significantly impaired the integrity of skin barrier, damaged skin structure, and disrupted water-oil balance. Furthermore, the analysis of α-diversity, Sobs, Ace and Chao index were found to significantly decrease (P < 0.05) in the late bedtime group, suggesting that late bedtime reduced both the abundance and the diversity of facial bacterial microbiota. Moreover, the abundance of Pseudomonas increased significantly, while Streptococcus, Stenotrophomonas, Acinetobacter, Haemophilus, Actinomyces and Neisseria decreased significantly. In addition, Spearman correlation analysis revealed strong correlations between the microbiota and the physiological parameters. Notably, the abundance of Pseudomonas significantly positively correlated with skin firmness and elasticity, but significantly negatively correlated with skin hemoglobin content, melanin content and skin hydration. Conclusion: Bedtime is an important factor in maintaining skin health. Regular late bedtime not only damages the skin barrier and skin structure but also reduces the diversity and composition of facial bacterial microbiome.

Deciphering the Sb4O5Cl2-MXene Hybrid as a Potential Anode Material for Advanced Potassium-Ion Batteries.

Potassium-ion batteries (PIBs) possess great potential in new-generation large-scale energy storage. However, their applications are plagued by large volume change and sluggish reaction kinetics of the electrode materials during the repeated charge/discharge processes. Guided by computerization modeling, we, herein, report the atomic-scale interfacial regulation of Sb4O5Cl2 coupled with structural engineering for the robust anode material of PIBs via simple MXene hybridization using a microwave-assisted hydrothermal method. Benefiting from the ostensive interfacial interplay between Sb4O5Cl2 and Ti3C2, MXene hybridization induces a favorable variation in spin polarization densities and the coordination of Sb atoms in Sb4O5Cl2, which are effective in optimizing the K+ ion diffusion path, thus resulting in a significantly reduced K+ ion diffusion barrier and promoted K+ insertion/extraction kinetics. The as-prepared Sb4O5Cl2-MXene anodes exhibit a highly reversible discharge capacity and decent cyclability, in addition to the low discharge plateau and promising full cell performance. This work is pivotal for not only paving the way for the exploration of anode materials for high-performance PIBs but also shedding light on the fundamental research on K+ ion storage in antimony oxychloride.

An on-demand and on-site shape-designable mineralized hydrogel with calcium supply and inflammatory warning properties for cranial repair applications.

Although more than 2.2 million cranial repair surgical operations are performed every year, orthopedic doctors still dream of excellent artificial repair materials with suitable strength, on-site and on-demand fast-shaping properties, and bone induction properties. However, fast-shaping and high-strength properties seem to contradict each other, and even mineralized hydrogels, which already have excellent strength and bone induction properties, are not ideal candidates, since they lack the plasticity needed for complex craniofacial surface use during the essential mechanism of the process of the cleavage of inorganic ions, nucleation, and growth. Here, we report a novel mineralized hydrogel based on dispersing mineral ions prior to use and then inducing inorganic formation by decreasing the temperature, which endows the hydrogels with the characteristics of precise customization at an appropriate degree of mineralization and simultaneously achieves suitable mechanical properties and sufficient calcium supply for bone regeneration. Additionally, the calcium ion content in the water of the matrix will change with the temperature, and, thus, the conductivity of the mineralized hydrogels will change accordingly. This implements the ability to warn of inflammation in a timely fashion in the form of a temperature sensor. Therefore, this temperature-responsive hydrogel effectively achieves the aim of versatile material design.

Highly anisotropic thermal conductivity and electrical insulation of nanofibrillated cellulose/Al2O3@rGO composite films: effect of the particle size.

Nanofibrillated cellulose (NFC) film has received tremendous attention due to its excellent electrical insulation, which shows great application prospects in the field of electronic devices. However, the low efficient heat dissipation of NFC film largely limits its use in advanced applications. In this work, the reduced graphene oxide hybrid fillers loaded alumina (Al2O3) particles with different sizes were synthesized by different drying methods, and then they were mixed with NFC to prepare a series of NFC-based composite films. The effect of Al2O3particle sizes on the thermal conductivity of NFC-based composite films was studied. The results showed that the surface areas of l-Al2O3particles were smaller than that of s-Al2O3particles, resulting in the smaller interface thermal resistance and superior thermal conductivity of the film containing l-Al2O3particles. The NFC-based composite films showed great potential for applications in thermal management by adjusting the particle size of fillers.

Contradiction or Unity? Thermally Stable Fluorescent Probe for In Situ Fast Identification of Self-sort or Co-assembly of Multicomponent Gelators with Sensitive Properties.

Analyzing the assembly patterns of multicomponent gelators is important for understanding their assembly rules and precisely manipulating their molecular structure to form a tailored multifunctional supramolecular gel. But the fast in situ recognition technology to infer whether the assembly pattern is a self-sorting or co-assembled system is lacking. For developing a widely applicable stable and sensitive fluorescent probe to infer assembly patterns, we design and synthesize the multiple peripheral functional group tetraphenylethene (TPE) modified well-defined cubic core polyhedral oligomeric silsesquioxane (POSS) three-dimensional (3D) dendrimer. POSS-TPE can form a thermally stable self-assembly structure after being incubated in a wide temperature range, and the resultant special thermally stable photoluminescence (PL) intensity provides a novel possibility of fluorescent probe. Then, POSS-TPE sensitively catches the mechanical stress changes of the confined space provided by the gel networks and infers the assembly patterns by comparing the mechanical stress change laws of a self-sorting or co-assembled system. So, the application of fluorescent probe in assembly fields is enlarged in this research. In the future, this widely applicable fluorescent probe will be helpful to develop supramolecular assembly materials consisting of multicomponent gels.

Driving force balance-the "identity card" of supramolecules in a self-sorting multicomponent assembly system.

Contrary to the popular belief that multicomponent assembly systems will theoretically co-assemble under the same type of driving forces, two distinct assembly modes from a system composed of two chemically similar supramolecules were demonstrated in this work. Although with exactly the same driving forces, molecule-level self-sorting unexpectedly occurred in this two-component system made of polyhedral oligomeric silsesquioxane (POSS) core-based supramolecules with one and eight lysine derivative arms. From the experiments, it was concluded that instead of driving force types, driving force counterpoise plays a vital role here, which we called "identity card hypothesis". The hypothesis suggests that two highly similar components show high affinity for the same molecules through the differentiated "identity card"-like balance of driving forces induced by the difference in the molecular spatial shape, which has never been reported before.

Health Literacy and Its Mediating Role in Predicting Health Behaviors Among Chinese Secondary Students.

While health literacy research in mainland China has gained increasing attention, most studies focus on adults. This study aimed to examine the mediating role of health literacy in the relationship between a range of upstream factors and health behaviors among Chinese secondary students. A cross-sectional study was conducted with 650 students in Years 7 to 9 from four secondary schools in Beijing. Based on an adapted health literacy framework from Manganello, a self-administered questionnaire was designed to collect information on upstream factors, health literacy, and health behaviors. Path analysis results showed that the proposed framework was mostly supported by empirical data after modification indices were examined and 3 direct paths were added. Students' self-efficacy, social support, and school environment were associated with health literacy, which in turn predicted health behaviors. A holistic approach is needed to improve both adolescent health literacy and health behaviors for Chinese school-aged adolescents.

Widely Applicable AIE Chemosensor for On-Site Fast Detection of Drugs Based on the POSS-Core Dendrimer with the Controlled Self-Assembly Mechanism.

A novel fluorescence chemosensor that can quickly on-site detect synthetic drugs and undergo prescreening is first reported. An eight tetraphenylethene (TPE)-modified polyhedral oligomeric silsesquioxane (POSS) dendrimer is designed and synthesized as an aggregation-induced emission (AIE) chemosensor, which exhibits great enhancement of unique monomer emission in pure tetrahydrofuran (THF) and AIE emission in THF/water, thanks to forming different self-assembly morphologies. In addition, POSS-TPE can sensitively detect methamphetamine and ketamine even in artificial saliva by noncovalent interaction forces. It has great potential to be a new widely applicable AIE chemosensor for aromatic molecules.

Analysis of the needs of students, parents and teachers for comprehensive sexuality education content / 中国学校卫生

Objective@#To understand the needs of primary and secondary school students, parents and teachers for comprehensive sexuality education content, and to explore the applicability of comprehensive sexuality education content in China.@*Methods@#By using the method of stratified cluster sampling, 5 571 primary and middle school students and 4 835 parents from Beijing, Chongqing, Heilongjiang (Harbin and Jiamusi) and Hubei (Wuhan and Xiaogan) were selected for questionnaire survey. Depending on the physical health monitoring points of various provinces and cities, 176 sexuality education related teachers in nine regions were surveyed. The development of the questionnaire was based on the content framework of comprehensive sexuality education proposed in the International Technical Guidelines for Sexuality Education.@*Results@#Students had a higher demand for knowledge on the concepts of "relationship" (53.4% for primary school students, 57.6% for junior high school students) and "health and well-being skills" (71.1% for primary school students, 55.9% for junior high school students). Parents had higher demand for most comprehensive sexuality education content with the exception of lower need for "sex and sexual behavior (74.7% of primary school parents, 80.8% of junior high school parents)" and "sexual and reproductive health (primary parents 74.3%, junior high school parents 75.8%)". Teachers had a high demand for most comprehensive sexuality education content, but primary school teachers had a lower need for "values, rights, culture and sex(65.9%)", "sex and sexuality(60.1%)" and "sexual and reproductive health(66.8%)". The results of correspondence analysis showed that junior middle school teachers had the highest demand for comprehensive education content, followed by primary school parents, junior middle school parents, primary school teachers, junior middle school students and primary school students.@*Conclusion@#Teachers and parents have a higher demand for most comprehensive sexuality education content, while lower demand for some relatively sensitive content. Students have a relatively low demand for comprehensive sexuality education content. It is recommended to further improve the content of school sexuality education based on the actual needs of China.