Dynamics of polylactic acid under ultrafine nanoconfinement: The collective interface effect and the spatial gradient.

Polymers under nanoconfinement can exhibit large alterations in dynamics from their bulk values due to an interface effect. However, understanding the interface effect remains a challenge, especially in the ultrafine nanoconfinement region. In this work, we prepare new geometries with ultrafine nanoconfinement ∼10nm through controlled distributions of the crystalline phases and the amorphous phases of a model semi-crystalline polymer, i.e., the polylactic acid. The broadband dielectric spectroscopy measurements show that ultrafine nanoconfinement leads to a large elevation in the glass transition temperature and a strong increment in the polymer fragility index. Moreover, new relaxation time profile analyses demonstrate a spatial gradient that can be well described by either a single-exponential decay or a double-exponential decay functional form near the middle of the film with a collective interface effect. However, the dynamics at the 1-2 nm vicinity of the interface exhibit a power-law decay that is different from the single-exponential decay or double-exponential decay functional forms as predicted by theories. Thus, these results call for further investigations of the interface effect on polymer dynamics, especially for interfaces with perturbed chain packing.

Photocatalytic Aptamer Chemiluminescent System for a Homogeneous, Reliable, Label-Free, Generic Assay of Small Molecules.

Chemiluminescence is a powerful analytical technique with many advantages, while aptamers are well-known as good molecular recognition units. However, many aptamer-based chemiluminescence assays employed interface sensing, which often needed several immobilization, separation, and washing steps. To minimize the risks of contamination and false-positive, we for the first time proposed a photocatalytic aptamer chemiluminescent system for a homogeneous, label-free, generic assay of small molecules. After binding to a DNA aptamer, thioflavin T has a unique photocatalytic oxidase activity to activate the system's luminol chemiluminescence. Then, the specific binding between the aptamer and target molecules will compete with the above process. Therefore, we can realize the efficient assay of different analytes including estradiol and adenosine. Such a homogeneous chemiluminescent system allowed a direct assay of small molecules with limits of detection in a nM level. Several control tests were carried out to avoid possible false-positive results, which were originated from the interactions between analytes and sensing interfaces previously. This homogeneous chemiluminescent system provides a useful strategy to reliably assay various analytes in the pharmacy or biology field.

Versatile DNA Balances via Adjacent Base Stacking for Homogeneous Assay of Energy Parameters, Small Molecules, And Ribonuclease.

Homogeneous assays often obviate any separation and washing steps, thus minimizing the risks of contamination and false positive. DNA toehold exchange is a homogeneous, reversible process whose thermodynamic properties can be finely tuned for various assay applications. However, the developed probes often rely on direct interactions of analytes with DNA strands involved in toehold exchange, limiting the versatility of probe design. Here, the coaxial adjacent stacking between one auxiliary strand and another invading strand offers a favorable ΔG to shift one DNA balance, while the auxiliary strand is independent of the DNA balance itself. Therefore, such a DNA balance allowed fine tuning of the equilibrium via adjustment of the auxiliary strand alone. The energy contribution of base stacking can be quantified in a homogeneous solution based on the difference in the equilibrium constant. Besides, the proof of concept for DNA balance allows effective assay of a small molecule or ribonuclease in a homogeneous solution. This novel DNA balance via adjacent base stacking provides an interesting alternative to homogeneously assay various analytes.

A Nanoconfined Water-Ion Coordination Network for Flexible Energy-Dissipation Devices.

Water-ion interaction in a nanoconfined environment that deeply constrains spatial freedoms of local atomistic motion with unconventional coupling mechanisms beyond that in a free, bulk state is essential to spark designs of a broad spectrum of nanofluidic devices with unique properties and functionalities. Here, it is reported that the interaction between ions and water molecules in a hydrophobic nanopore forms a coordination network with an interaction density that is nearly fourfold that of the bulk counterpart. Such strong interaction facilitates the connectivity of the water-ion network and is uncovered by corroborating the formation of ion clusters and the reduction of particle dynamics. A liquid-nanopore energy-dissipation system is designed and demonstrated in both molecular simulations and experiments that the formed coordination network controls the outflow of confined electrolytes along with a pressure reduction, capable of providing flexible protection for personnel and devices and instrumentations against external mechanical impact and attack.

[Advances in organoids of the digestive system].

Organoid is a newly developed cellular there-dimensional culture system in recent years. Organoids have a three-dimensional structure, which is similar to that of the real organs. Together with the characteristics of self-renewal and reproduction of tissue origin, organoids can better simulate the function of real organs. Organoids provide a new platform for the study of organogenesis, regeneration, disease pathogenesis, and drug screening. The digestive system is an essential part of the human body and performs important functions. To date, organoid models of various digestive organs have been successfully established. This review summarizes the latest research progress of organoids of taste buds, esophagi, stomachs, livers and intestines, and prospects future application of organoids.

Simulation-Guided Rational Design of DNA Probe for Accurate Discrimination of Single-Nucleotide Variants Based on "Hill-Type" Cooperativity.

The accurate discrimination of single-nucleotide variants is of great interest for disease diagnosis and clinical treatments. In this work, a unique DNA probe with "Hill-type" cooperativity was first developed based on toehold-mediated strand displacement processes. Under simulation, this probe owns great thermodynamics advantage for specificity due to two mismatch bubbles formed in the presence of single-nucleotide variants. Besides, the strategies of ΔG' = 0 and more competitive strands are also beneficial to discriminate single-nucleotide variants. The feasibility of this probe was successfully demonstrated in consistent with simulation results. Due to "Hill-type" cooperativity, the probe allows a steeper dynamic range compared with previous probes. With simulation-guided rational design, the resulting probe can accurately discriminate single-nucleotide variants including nucleotide insertions, mutation, and deletions, which are arbitrarily distributed in target sequence. Two specificity parameters were calculated to quantitatively evaluate its good discrimination ability. Hence, "Hill-type" cooperativity can serve as a novel strategy in DNA probe's design for accurate discrimination of single-nucleotide variants.

Social environment exposure to electronic cigarettes and its association with e-cigarette use among adolescents in Shanghai, China.

Objective: This study investigated adolescents' social-environmental exposure to e-cigarettes in association with e-cigarette use in Shanghai, China. We also explored these differences by gender and school type. Methods: Sixteen thousand one hundred twenty-three students were included by a stratified random cluster sampling, and the number was weighted according to selection probability. Association between social environment exposure and e-cigarette use was examined by multivariate logistic regressions. Results: There were 35.07, 63.49, 75.19, 9.44, and 18.99% students exposed to secondhand e-cigarette aerosol (SHA), e-cigarette sales, e-cigarette information, parents' and friends' e-cigarette use. Students exposed to SHA (aOR = 1.73, 95% CI 1.40-2.14), e-cigarette sales from ≥2 sources (aOR = 1.55, 95% CI 1.18-2.03), e-cigarette information exposure from ≥2 sources (aOR = 1.39, 95% CI 1.05-1.83), and having a social e-smoking environment (friends' e-cigarette use: aOR = 2.56, 95% CI 2.07-3.16; parents' e-cigarette use: aOR = 1.54, 95% CI 1.17-2.02) were significantly associated with their intention to use e-cigarettes. More girls were exposed to e-cigarette sales in the malls, e-cigarette information at points of sale and on social media (P < 0.01), and exposure to sales from ≥2 sources were associated with girls' intention to use e-cigarettes (aOR = 1.84, 95% CI 1.22-2.78). However, boys were more likely to be exposed to friends' e-cigarette use (P < 0.001), and having friends using e-cigarettes was associated with greater intention to use them in boys (aOR = 2.64, 95% CI 1.97-3.55). Less vocational high school students were exposed to parents' e-cigarette use (P < 0.001), but they were more likely to use e-cigarettes in the future after being exposed (aOR = 2.27, 95% CI 1.50-3.43). A similar phenomenon was observed between junior high students and their exposure to SHA. Conclusions: This study reported adolescents' high exposure rates to the social environment of e-cigarettes. Exposure to SHA, e-cigarette sales from ≥2 sources, e-cigarette information from ≥2 sources and having a social e-smoking environment were related to adolescents' intention to use e-cigarettes. Differences in gender and school type were observed. More attention should be paid to girls, and different interventions should be designed for different types of school students. Additionally, comprehensive tobacco control policies are needed.

Body Weight, Weight Self-Perception, Weight Teasing and Their Association with Health Behaviors among Chinese Adolescents-The Shanghai Youth Health Behavior Survey.

Weight-related status has been associated with the physical and psychological health of adolescents. This cross-sectional study evaluated three different kinds of weight-related statuses (Body Mass Index (BMI), weight self-perception and weight teasing from others) among Chinese adolescents and identified their associations with health risk behaviors (lack of healthy dietary behavior, unhealthy dietary behavior, binge eating behavior, lack of physical activity (PA), sedentary behaviors (SB) and sleep disturbance). A stratified random cluster sampling method was used to select 10,070 students aged 11−18 years old from schools in Shanghai. Self-reported questionnaires were collected, weight-related statuses were divided into three categories and six specific health risk behaviors were classified into two groups: positive or negative. Overall, 27.82% of the adolescents were classified as being overweight and obese (35.61% of boys and 18.21% of girls), 43.45% perceived themselves as too heavy and 30.46% experienced weight teasing in the past. Among overweight or obese participants, 50.55% have been teased about their weight, and 77.48% perceived themselves as too heavy. Weight perception and weight teasing were significantly associated with health risk behaviors rather than the actual body weight status based on BMI, especially regarding binge eating behavior (body weight status (BMI): p > 0.05, underweight perception: OR = 1.18, 95%CI 1.03−1.34; weight teasing for more than once a year: OR = 2.00, 95%CI 1.76−2.27). In addition, weight perception and weight teasing were significantly associated with health risk behaviors, mainly in normal and overweight/obese groups but not in underweight groups. Weight teasing and weight self-perception play an independent and stronger role than actual body weight in the health behaviors of adolescents. This calls for more attention and intervention to reduce peer bullying and stigmas on weight among adolescents.

Electronic health literacy and health-related outcomes among older adults: A systematic review.

This review aims to identify, appraise, and synthesize research evidence of the association between electronic health (eHealth) literacy and health outcomes in older adults. English-written articles that presented the relationships between eHealth literacy and health-related outcomes in older adults were identified by searching five scientific databases (Web of Science, PubMed, Cochrane Library, APA PsycInfo, and EMBASE) hand-searching reference lists. Searches yielded 2993 studies after duplicates were removed, of which 24 publications were included in the final review. eHealth literacy was relatively low in older adults, and the eHealth Literacy Scale, developed by Norman and Skinner in 2006, was the most frequently used instrument in the included studies (21/24, 87.5%). The health-related outcomes associated with eHealth literacy were grouped into four categories: physical, behavioral, psychosocial, and cognitive. For behavioral (e.g., health-promoting behaviors, self-care, and medication adherence) and cognitive (e.g., health knowledge and health decision making) outcomes, the evidence was mostly consistent that eHealth literacy was positively associated with better outcomes. For physical (e.g., health-related quality of life) and psychosocial outcomes (e.g., anxiety and self-efficacy), the associations were less consistent, with some studies showing significant associations while others showed no associations. Most included studies were assessed as moderate quality. Overall, higher eHealth literacy is associated with more positive health behaviors and better health knowledge and attitude in older adults, however, the associations with some physical and psychosocial outcomes are less consistent. Clarifying the pathways of the relationships between eHealth literacy and some health-related outcomes is needed for further exploring their underlying mechanisms.

Current Assessment of Weight, Dietary and Physical Activity Behaviors among Middle and High School Students in Shanghai, China-A 2019 Cross-Sectional Study.

Poor nutrition or insufficient physical activity (PA) are risk factors for obesity and chronic diseases. This 2019 cross-sectional study from the school health survey examined the dietary and PA behaviors of Chinese adolescents. A total of 12,860 adolescents aged 11-18 participated through multistage and stratified cluster random sampling. A questionnaire collected data on weight, PA, sedentary lifestyle, and eating habits. Unhealthy behaviors were identified and summed up for each behavior. Participants were then classified into high and low amounts of risk behaviors. Weight status was defined using Body Mass Index (BMI) cutoff points for Chinese individuals aged 6-18. Multinomial logistic regression was used to assess effects of lifestyle behaviors on weight status. The prevalence of overweight and obesity was 22.3% among all participants (30.6% in boys, 13.2% in girls). Females engaged in more risk physical activities (4.12 vs. 3.80, p < 0.05), while males engaged in more risk dietary activities (2.20 vs. 2.02, p < 0.05). Higher number of risk dietary, PA, and sedentary behaviors were all significantly correlated with higher BMI (dietary: r = 0.064; PA: r = 0.099; sedentary: r = 0.161; p < 0.001 for all) and body weight (dietary: r = 0.124; PA: r = 0.128; sedentary: r = 0.222; p < 0.001 for all). Risk sedentary behaviors was a significant risk factor for overweight/obesity (Adjusted Odds Ratio AOR = 1.30, 95% Confidence Interval CI 1.11-1.52). Obesity and unhealthy lifestyle behaviors remain a concern among Chinese adolescents. These results provide an update on the factors contributing to overweight/obesity among adolescents and call for efforts to address obesity among adolescents.

Wound drainage after proximal femoral nail antirotation (PFNA) fixation may negatively affect the patients with intertrochanteric fractures: A prospective randomized controlled trial.

INTRODUCTION: The effect of using closed suction drainage system with the proximal femoral nail antirotation (PFNA) system fixation on outcomes in treating intertrochanteric fractures (ITFs) is still unknown. This prospective randomized controlled trial aimed to examine whether routine drainage is useful for PFNA fixation in ITFs. METHODS: A total of 80 patients with acute ITFs were treated with closed or mini-open reduction with PFNA fixation at the National Cheng Kung University Hospital and 60 eligible patients were randomized for whether to receive suction drainage. In clinical outcomes, the visual analog scale (VAS), morphine equivalent dosage, injured thigh width, body temperature, wound condition and wound infection were measured on postoperative day 1, 2, 4, 10, and 90. In laboratory outcomes, we evaluated hemoglobin and hematocrit levels postoperatively at different time points. Blood transfusion and total blood loss (TBL) were measured by Mercuriali's formula in millimeter. RESULTS: The results revealed that the amount of blood transfusion received by the drained group (543.3 mL) was more than that by the undrained group (367.8 mL; p = 0.0074), and similarly, TBL in the drained group (750.1 mL) was more than that in the undrained group (537.4 mL; p = 0.0067). Regarding clinical and laboratory outcomes, compared with the undrained group, the drained group had a higher VAS score on postoperative day 2 (p = 0.0216). No difference was observed between the 2 groups for morphine equivalent dosage, thigh swelling, wound infection and hematoma, hospitalization period, or total number of complications at every time point after index procedure. CONCLUSIONS: Blood transfusion requirement and TBL were higher in the drained group than in the undrained group of PFNA fixation for ITFs. In addition, the closed drainage system may have manifested no short-term benefit for wound condition postoperatively.

Spontaneous outflow efficiency of confined liquid in hydrophobic nanopores.

The suspension of nanoporous particles in a nonwetting liquid provides a unique solution to the crux of superfluid, sensing, and energy conversion, yet is challenged by the incomplete outflow of intruded liquid out of nanopores for the system reusability. We report that a continuous and spontaneous liquid outflow from hydrophobic nanopores with high and stable efficiency can be achieved by regulating the confinement of solid-liquid interactions with functionalized nanopores or/and liquids. Full-scale molecular-dynamics simulations reveal that the grafted silyl chains on nanopore wall surfaces will promote the hydrophobic confinement of liquid molecules and facilitate the molecular outflow; by contrast, the introduction of ions in the liquid weakens the hydrophobic confinement and congests the molecular outflow. Both one-step and multistep well-designed quasistatic compression experiments on a series of nanopores/nonwetting liquid material systems have been performed, and the results confirm the outflow mechanism in remarkable agreement with simulations. This study offers a fundamental understanding of the outflow of confined liquid from hydrophobic nanopores, potentially useful for devising emerging nanoporous-liquid functional systems with reliable and robust reusability.

Effect of Extra Gas Amount on Liquid Outflow from Hydrophobic Nanochannels: Enhanced Liquid-Gas Interaction and Bubble Nucleation.

Understanding liquid motion in nanoenvironment is of fundamental importance in nanofluidics-based systems. While the liquid outflow from hydrophobic nanochannels can significantly affect system performance, its underlying mechanism remains unclear so far. Here, we present an experimental study of the gas-phase effect on liquid outflow behavior from hydrophobic nanochannels in a liquid nanofoam (LN) system. Four LN samples, consisting of same liquid-solid composition but different amounts of the gas phase, are characterized by cyclic quasi-static compression tests. A remarkable difference in the LN system reusability has been observed, indicating that the liquid outflow behavior is highly sensitive to the amount of the gas phase. As the gas amount increases, the degree of liquid outflow from hydrophobic nanochannels is considerably promoted. This promotive effect is because of the suppression of gas outflow and acceleration of bubble nucleation in the nanochannels. These fundamental findings open a new perspective on liquid outflow behavior and can facilitate the design of reusable nanofluidics-based energy absorbers.

Mg Doped Li-LiB Alloy with In Situ Formed Lithiophilic LiB Skeleton for Lithium Metal Batteries.

High energy density lithium metal batteries (LMBs) are promising next-generation energy storage devices. However, the uncontrollable dendrite growth and huge volume change limit their practical applications. Here, a new Mg doped Li-LiB alloy with in situ formed lithiophilic 3D LiB skeleton (hereinafter called Li-B-Mg composite) is presented to suppress Li dendrite and mitigate volume change. The LiB skeleton exhibits superior lithiophilic and conductive characteristics, which contributes to the reduction of the local current density and homogenization of incoming Li+ flux. With the introduction of Mg, the composite achieves an ultralong lithium deposition/dissolution lifespan (500 h, at 0.5 mA cm-2) without short circuit in the symmetrical battery. In addition, the electrochemical performance is superior in full batteries assembled with LiCoO2 cathode and the manufactured composite. The currently proposed 3D Li-B-Mg composite anode may significantly propel the advancement of LMB technology from laboratory research to industrial commercialization.

Effect of Electrolytes on Gas Oversolubility and Liquid Outflow from Hydrophobic Nanochannels.

We have experimentally studied the effect of electrolytes on gas oversolubility and liquid outflow from hydrophobic nanochannels. By immersing nanoporous material with the same porous structure and surface properties into four different aqueous electrolyte solutions with the same surface tension, the excessive solid-liquid interfacial tension of the resulted liquid nanofoam (LN) systems has been set as a constant. Upon unloading, partial liquid outflow has been observed and quantified. As the four LN systems show different degrees of recoverability, it suggests that the degree of liquid outflow is highly sensitive to the ion species. In addition, different from bulk phase scenario, the anions have a more profound effect than cations on gas oversolubility. Lower bulk gas solubility and larger gas oversolubility factor lead to higher degree of liquid outflow and recoverability of the LN systems. This fundamental understanding on the mechanism of liquid outflow enables the development of nanofluidics-based system into reusable energy absorbers.

Synthesis and Characterization of N,N,O-Tridentate Aminophenolate Zinc Complexes and Their Catalysis in the Ring-Opening Polymerization of Lactides.

A series of aminophenolate ligands with various pendant groups and associated ethyl Zn complexes were synthesized and studied as catalysts for the ring-opening polymerization (ROP) of lactides (LAs). The thiophenylmethyl group (L 4 ZnEt) increased the catalytic activity more than the benzyl group (L 1 ZnEt) did, and 2-fluorobenzyl (L 3 ZnEt) and 2-methoxybenzyl (L 2 ZnEt) groups had the opposite effect. In addition, the LA polymerization mechanism proved by Nuclear Magnetic Resonance and Density Function Theory was that LA was attracted by H···O bond of an α-hydrogen of the LA molecule and the phenoxyl oxygen of the catalyst. After the dissociation of amino group from the Zn atom, the benzyl alcohol initiated LA without replacing the ethyl group of Zn complex. It is the first case where the ethyl group is regarded as a ligand and cannot be replaced by benzyl alcohol, and this information is very important for the mechanism study of ROP.

Compressing liquid nanofoam systems: liquid infiltration or nanopore deformation?

Understanding the invasion of a liquid into porous structures is the foundation of the characterization of the porosity-related properties of materials and is also of fundamental importance in the design of porous solid-liquid enabled energy protection systems, yet whether solid pores deform has been unclear so far. Here, we present a competition mechanism between liquid infiltration and cell wall buckling deformation by investigating a liquid nanofoam (LN) system subjected to quasi-static compression. The critical buckling stress of the cell wall and the infiltration pressure of liquid invasion into nanopores are studied and correlated through numerical simulation and experimental validation to reveal the quantitative relationship between nanopore deformation and liquid invasion. The analysis shows that liquid infiltration occurs, independent of the axial buckling stress of the cell wall; in contrast, the nanopore collapses radially when the radial collapse pressure is lower than the pressure of liquid infiltration, preventing the liquid invasion. Comprehensive molecular dynamics (MD) simulations are performed and demonstrate the deformation behavior of nanopores and cell wall-liquid interactions in a broad range. Pressure-induced compression experiments on a silica-based LN system are carried out and validate these theoretical and MD results.

Enhanced Catalytic Activity of Aluminum Complexes for the Ring-Opening Polymerization of ε-Caprolactone.

A series of dinuclear aluminum (Al2Pyr2) complexes bridged by two pyrazole ligands were synthesized, and their catalytic activity toward ring-opening polymerization of ε-caprolactone (CL) was investigated. Different types of the Al-N-N-Al-N-N skeletal ring were found among these Al2Pyr2 complexes. The butterfly form, LThio2Al2Me4, exerted the highest catalytic activity for CL polymerization. κ2-CL coordination with both Al centers within the butterfly form LThio2Al2Me4 facilitates the initiation process. Generally speaking, the Al2Pyr2 complexes exhibited substantially higher catalytic activity for CL polymerization than literature examples such as ß-diketiminate- or traiaza-bearing aluminum complexes. In fact, the Al2Pyr2 complexes can even carry out CL polymerization at room temperature.

Adaptive liquid flow behavior in 3D nanopores.

Liquid flow speed in 2D nanochannel models has previously been characterized, whereas liquid flow behavior in 3D nanostructured materials remains unknown. To fill this gap, we have developed a novel liquid nanofoam (LN) system composed of nanoporous silica gel particles and a non-wettable liquid phase. We demonstrated that the dynamic behavior of the LN sample was strain rate insensitive by impacting it with a drop weight at various incident speeds. Using this experimental setup, we measured the effective liquid flow speed in 3D nanopores and showed that it was 5 orders of magnitude higher than that of quasi-static loading. Importantly, the liquid infiltration speed as well as the energy absorption efficiency of the LN was found to be adaptive to the incident speed and energy level. This provides a mechanistic explanation for the high energy absorption efficiency of LNs at high blast impact levels and strain rates, and demonstrates the importance of experimentally investigating the liquid flow behavior in 3D instead of the traditional 2D nanopores.

Synthesis of Sodium Complexes Supported with NNO-Tridentate Schiff Base Ligands and Their Applications in the Ring-Opening Polymerization of L-Lactide.

A series of sodium complexes bearing NNO-tridentate Schiff base ligands with an N-pendant arm were synthesized and used as catalysts for the ring-opening polymerization of L-lactide (L-LA). Electronic effects of ancillary ligands coordinated by sodium complexes substantially influence the catalysis, and ligands with electron-donating groups increase the catalytic activity of the sodium complexes for catalyzing L-LA polymerization. In particular, a sodium complex bearing a 4-methoxy group has the highest activity with conversion up to 95% within 30 s at 0 °C and a low polydispersity index of 1.13, whereas the 4-bromo group showed the poorest performance with regard to the catalytic rate of L-LA polymerization in the presence of benzyl alcohol (BnOH). (1)H NMR pulsed-gradient spin-echo diffusion experiments and single-crystal X-ray analyses showed that sodium complexes [L(H)Na(THF)]2 and [L(4-Cl)Na(THF)]2 were dinuclear species in both solution and the solid state. The kinetic results indicated a first-order dependence on each of [[L(4-Cl)Na]2], [l-LA], and [BnOH].