Supramolecular/Dynamic Covalent Design of High-Performance Pressure-Sensitive Adhesive from Natural Low-Molecular-Weight Compounds.

Adhesive materials have played an essential role in the history of humanity. Natural adhesives composed of low-molecular-weight monomers have been overshadowed by modern petroleum-based glues. With the development of green economy, the demand for eco-friendly materials has increased. Herein, two natural biocompatible compounds, namely thioctic acid (TA) and malic acid (MA), are selected to prepare a high-performance pressure-sensitive adhesive poly[TA-MA]. This adhesive can be quantitatively obtained via a simple mixing and heating process. Poly[TA-MA] shows interesting and useful properties, including reversible flexibility, high elongation, and good self-healing, owing to its dynamic polymerization pattern and reversible cross-linking behavior. Poly[TA-MA] exhibits excellent adhesion performance under various extreme conditions, such as at low temperatures and in hot water. High values of shear strength (3.86 MPa), peel strength (7.90 N cm-1), loop tack (10.60 N cm-1), tensile strength (1.02 MPa), and shear resistance (1628 h) demonstrate the strong adhesive effect of poly[TA-MA]. Additionally, TA can be regenerated in the monomer forms from poly[TA-MA] with high recovery rate (>90%). Meanwhile, strong anti-bacterial behavior of poly[TA-MA] is recorded. This study not only reported a new pressure-sensitive adhesive but also fully displayed the feasibility of using natural small molecules to achieve robust surface adhesion.

Thermal-tagging photoacoustic remote sensing flowmetry.

Ultrasound coupling is one of the critical challenges for traditional photoacoustic (or optoacoustic) microscopy (PAM) techniques transferred to the clinical examination of chronic wounds and open tissues. A promising alternative potential solution for breaking the limitation of ultrasound coupling in PAM is photoacoustic remote sensing (PARS), which implements all-optical non-interferometric photoacoustic measurements. Functional imaging of PARS microscopy was demonstrated from the aspects of histopathology and oxygen metabolism, while its performance in hemodynamic quantification remains unexplored. In this Letter, we present an all-optical thermal-tagging flowmetry approach for PARS microscopy and demonstrate it with comprehensive mathematical modeling and ex vivo and in vivo experimental validations. Experimental results demonstrated that the detectable range of the blood flow rate was from 0 to 12 mm/s with a high accuracy (measurement error:±1.2%) at 10-kHz laser pulse repetition rate. The proposed all-optical thermal-tagging flowmetry offers an effective alternative approach for PARS microscopy realizing non-contact dye-free hemodynamic imaging.

Supramolecular Soft Material Enabled by Metal Coordination and Hydrogen Bonding: Stretchability, Self-Healing, Impact Resistance, 3D Printing, and Motion Monitoring.

Metal coordination can significantly improve the macroscopic performance of many materials by enhancing their dynamic features. In this study, two supramolecular interactions, Fe3+ -carboxylic acid coordination, and structural water-induced hydrogen bonding, into an artificial polymer were introduced. Various attractive features, including flexibility and stretchability, are achieved because of the bulk state and dynamic hydrogen bonds of poly(thioctic acid-water) (poly[TA-H]). These unique features are considerably enhanced after the incorporation of Fe3+ cations into poly[TA-H] because metal coordination increased the mobility of the poly[TA-H] chains. Thus, the poly(thioctic acid-water-metal) (poly[TA-HM]) copolymer exhibited better flexibility and stretchability. Moreover, notable underwater/low-temperature self-healing capacity is obtained via the synergistic effect of the metal and hydrogen bonding. Most of the impact energy is quickly absorbed by poly[TA-H] or poly[TA-HM] and effectively and rapidly dissipated via reversible debonding/bonding via the interactions between the metal and hydrogen. Macroscopic plastic deformation or structural failure is not observed during high-speed (50-70 m s-1 ) impact experiments or high-altitude (90 m) falling tests. Furthermore, poly[TA-HM] displayed good thermal molding properties, which enabled its processing via 3D fused deposition modeling printing. Poly[TA-HM] also showed considerable effectiveness for monitoring complicated, dynamic, and irregular biological activities owing to its highly pressure-sensitive nature.

Limited view correction in low-optical-NA photoacoustic microscopy.

Photoacoustic microscope (PAM) with a low-optical NA suffers from a limited view along the optical axis, due to the coherent cancellation of acoustic pressure waves after being excited with a smoothly focused beam. Using larger-NA (NA > 0.3) objectives can readily overcome the limited-view problem, while the consequences are the shallow working distance and time-consuming depth scanning for large-volume imaging. Instead, we report an off-axis oblique detection strategy that is compatible with a low-optical-NA PAM for turning up the optical-axis structures. Comprehensive photoacoustic modeling and ex vivo phantom and in vivo mouse brain imaging experiments are conducted to validate the efficacy of correcting the limited view. Proof-of-concept experiment results show that the visibility of optical-axis structures can be greatly enhanced by making the detection angle off the optical axis larger than 45°, strongly recommending that off-axis oblique detection is a simple and cost-effective alternative method to solve the limited-view problems in low-optical-NA PAMs.

Dynamics and mechanisms of intracellular calcium waves elicited by tandem bubble-induced jetting flow.

One of the earliest events in cellular mechanotransduction is often an increase in intracellular calcium concentration associated with intracellular calcium waves (ICWs) in various physiologic or pathophysiologic processes. Although cavitation-induced calcium responses are believed to be important for modulating downstream bioeffects such as cell injury and mechanotransduction in ultrasound therapy, the fundamental mechanisms of these responses have not been elucidated. In this study, we investigated mechanistically the ICWs elicited in single HeLa cells by the tandem bubble-induced jetting flow in a microfluidic system. We identified two distinct (fast and slow) types of ICWs at varying degrees of flow shear stress-induced membrane deformation, as determined by different bubble standoff distances. We showed that ICWs were initiated by an extracellular calcium influx across the cell membrane nearest to the jetting flow, either primarily through poration sites for fast ICWs or opening of mechanosensitive ion channels for slow ICWs, which then propagated in the cytosol via a reaction-diffusion process from the endoplasmic reticulum. The speed of ICW (CICW ) was found to correlate strongly with the severity of cell injury, with CICW in the range of 33 µm/s to 93 µm/s for fast ICWs and 1.4 µm/s to 12 µm/s for slow ICWs. Finally, we demonstrated that micrometer-sized beads attached to the cell membrane integrin could trigger ICWs under mild cavitation conditions without collateral injury. The relation between the characteristics of ICW and cell injury, and potential strategies to mitigate cavitation-induced injury while evoking an intracellular calcium response, may be particularly useful for exploiting ultrasound-stimulated mechanotransduction applications in the future.

Deep Eutectic Supramolecular Polymers: Bulk Supramolecular Materials.

Application of new strategies for supramolecular self-assembly can significantly impact the properties and/or functions of supramolecular polymers. To realize a facial strategy for the development of solvent-free supramolecular polymers in bulk, "deep eutectic solvents" were employed. Cyclodextrins and natural acids were used to prepare deep eutectic supramolecular polymers (DESPs). Deep eutectic solvents have special characteristics that endow DESPs with unique macroscopic properties and excellent processability. DESPs exhibit supramolecular adhesion and temperature-dependent behavior originating from the combined effects of deep eutectic solvents and supramolecular polymerization. Because DESPs are solvent-free and display interesting macroscopic properties, they have potential as new adaptive materials.

Activation of Piezo1 mechanosensitive ion channel in HEK293T cells by 30 MHz vertically deployed surface acoustic waves.

Ultrasound (US) has emerged as a promising noninvasive modality for neuromodulation. Despite previous evidence that US may mediate cellular response by activating mechanosensitive ion channels embedded in the cell membrane, the underlying mechanism is not well understood. In this work, we developed a vertically deployed surface acoustic wave (VD-SAW) platform that generates 30 MHz focused ultrasound wave for mechanical stimulation of single cells. We investigated the role of Piezo1 in mediating the intracellular calcium response ( [Formula: see text] ) of HEK293T cells in response to pulsed US operated at a peak pressure of 1.6 MPa with 20% duty cycle, and a total treatment time of 60 s. We observed that the elicited calcium response depends critically on the pulse repetition frequency (PRF) or burst duration of the US, as well as the presence of the Piezo1. Significantly higher [Formula: see text] increase was produced in the Piezo1-transfected (P1TF) than in the Piezo1-knockout (P1KO) HEK293T cells. Furthermore, higher calcium response probability, stronger and faster [Formula: see text] increase, and greater cell displacement were produced at 2 Hz PRF with 100 ms burst duration than 200 Hz PRF with 1 ms burst duration. Altogether, we have demonstrated that the VD-SAW platform provides a unique and versatile tool for investigating US-induced mechanotransduction at the single cell level.

Trends and Racial Disparities of Late-Stage HIV Diagnosis: Hawaii, 2010-2016.

OBJECTIVES: To examine racial/ethnic disparities in Hawaii in stage 3 classification at HIV diagnosis and trends in such disparities from 2010 through 2016. METHODS: We analyzed data including patients' demographic information, behavioral risk factors, residential county at HIV diagnosis, and type of facility where HIV was diagnosed. Multivariable logistic regression modeling was used to examine racial/ethnic disparities in late-stage diagnoses after adjustment for known or possible confounders. RESULTS: About 30% of HIV diagnoses were classified as late-stage (stage 3) diagnoses, and there were significant racial/ethnic disparities in stage 3 classification at diagnosis. Relative to Whites, the odds of being diagnosed at stage 3 were 3.7 times higher among Native Hawaiians and other Pacific Islanders (NHPIs; odds ratio [OR] = 3.69; 95% confidence interval [CI] = 1.89, 7.22) and more than twice as high among Asians (OR = 2.46; 95% CI = 1.16, 5.20). Older age and being diagnosed in an inpatient setting were associated with stage 3 classification. CONCLUSIONS: Targeted preventive services need to be strengthened for Asians and NHPIs in Hawaii.

Dual burden of malnutrition in US Affiliated Pacific jurisdictions in the Children's Healthy Living Program.

BACKGROUND: Few data are available on dual burden of under and over nutrition of children in the Pacific region. The objective was to examine prevalence of stunting at birth and current stunting and their relationship to obesity in US Affiliated Pacific (USAP) jurisdictions. METHODS: Cross sectional survey with cluster sampling by community. 5558, 2-8 years olds were measured in 51 communities in 11 USAP jurisdictions. The main outcome measures were stunting at birth, current stunting and obesity by body mass index. Prevalences of stunting at birth, current stunting and obesity were determined, adjusting for age distribution and community clustering. Differences by among age, sex, race and jurisdiction income levels were evaluated by chi-square analysis. Relationships of stunting at birth and current stunting with obesity were examined using a hierarchical model accounting for the study design. RESULTS: Prevalences were stunting at birth 6.8% (Standard Error, SE = 0.9%), current stunting 1.4% (SE = 0.2%) and obesity 14.03.8% (SE = 0.9%). Obesity was highest in upper middle income jurisdictions (UMIJ) at 17.5%. Stunting at birth differed by race (p = 0.0001) with highest prevalence among Native Hawaiian/Pacific Islanders (10.7%). Prevalence of stunting at birth was different by jurisdiction income level with 27.5% in lower middle income jurisdictions (LMIJ), and 22.2% in UMIJ, and 5.5% in higher than high income jurisdictions (HIJ) at 5.5% (p < 0.0001). Prevalence of current stunting was higher in LMIJ than HIJ (p = 0.001), although children with current stunting were less likely to have been stunted at birth. The association between stunting at birth and current stunting was negative (OR = 0.19, 95% CI: 0.05-0.69). CONCLUSIONS: Currently stunted children were marginally less likely to be obese than not stunted children in the USAP, where the prevalence of current stunting is low. Stunting (at birth and current) was highest in LMIJ, while UMIJ jurisdictions had the highest dual burden of malnutrition (that is the highest combination of both stunting at birth and obesity). TRIAL REGISTRATION: National Institutes for Health clinical trial # NCT01881373 (clinicaltrials.gov).

Ultrasonic Assisted Extraction of Paclitaxel from Taxus x media Using Ionic Liquids as Adjuvants: Optimization of the Process by Response Surface Methodology.

(1) Background: Ionic liquids (ILs) are considered "green" solvents and have been widely used in the extraction and separation field in recent years; (2) Methods: In this study, some common ILs and functionalized magnetic ionic liquids (MILs) were used as adjuvants for the solvent extraction of paclitaxel from Taxus x media (T. x media) using methanol solution. The extraction conditions of methanol concentration, IL type and amount, solid-liquid ratio, extraction temperature, and ultrasonic irradiation time were investigated in single factor experiments. Then, three factors of IL amount, solid-liquid ratio, and ultrasonic irradiation time were optimized by response surface methodology (RSM); (3) Results: The MIL [C4MIM]FeCl3Br was screened as the optimal adjuvant. Under the optimization conditions of 1.2% IL amount, 1:10.5 solid-liquid ratio, and 30 min ultrasonic irradiation time, the extraction yield reached 0.224 mg/g; and (4) Conclusions: Compared with the conventional solvent extraction, this ultrasonic assisted extraction (UAE) using methanol and MIL as adjuvants can significantly improve the extraction yield, reduce the use of methanol, and shorten the extraction time, which has the potentiality of being used in the extraction of some other important bioactive compounds from natural plant resources.

Anthropometric measurement standardization in the US-affiliated pacific: Report from the Children's Healthy Living Program.

OBJECTIVES: Anthropometric standardization is essential to obtain reliable and comparable data from different geographical regions. The purpose of this study is to describe anthropometric standardization procedures and findings from the Children's Healthy Living (CHL) Program, a study on childhood obesity in 11 jurisdictions in the US-Affiliated Pacific Region, including Alaska and Hawai'i. METHODS: Zerfas criteria were used to compare the measurement components (height, waist, and weight) between each trainee and a single expert anthropometrist. In addition, intra- and inter-rater technical error of measurement (TEM), coefficient of reliability, and average bias relative to the expert were computed. RESULTS: From September 2012 to December 2014, 79 trainees participated in at least 1 of 29 standardization sessions. A total of 49 trainees passed either standard or alternate Zerfas criteria and were qualified to assess all three measurements in the field. Standard Zerfas criteria were difficult to achieve: only 2 of 79 trainees passed at their first training session. Intra-rater TEM estimates for the 49 trainees compared well with the expert anthropometrist. Average biases were within acceptable limits of deviation from the expert. Coefficient of reliability was above 99% for all three anthropometric components. CONCLUSIONS: Standardization based on comparison with a single expert ensured the comparability of measurements from the 49 trainees who passed the criteria. The anthropometric standardization process and protocols followed by CHL resulted in 49 standardized field anthropometrists and have helped build capacity in the health workforce in the Pacific Region. Am. J. Hum. Biol. 28:364-371, 2016. © 2015 Wiley Periodicals, Inc.

Systematic Review of Prevalence of Young Child Overweight and Obesity in the United States-Affiliated Pacific Region Compared With the 48 Contiguous States: The Children's Healthy Living Program.

We estimated overweight and obesity (OWOB) prevalence of children in US-Affiliated Pacific jurisdictions (USAP) of the Children's Healthy Living Program compared with the contiguous United States. We searched peer-reviewed literature and government reports (January 2001-April 2014) for OWOB prevalence of children aged 2 to 8 years in the USAP and found 24 sources. We used 3 articles from National Health and Nutrition Examination Surveys for comparison. Mixed models regressed OWOB prevalence on an age polynomial to compare trends (n = 246 data points). In the USAP, OWOB prevalence estimates increased with age, from 21% at age 2 years to 39% at age 8 years, increasing markedly at age 5 years; the proportion obese increased from 10% at age 2 years to 23% at age 8 years. The highest prevalence was in American Samoa and Guam.

Ionic Liquid-Based Ultrasonic-Assisted Extraction of Secoisolariciresinol Diglucoside from Flaxseed (Linum usitatissimum L.) with Further Purification by an Aqueous Two-Phase System.

In this work, a two-step extraction methodology of ionic liquid-based ultrasonic-assisted extraction (IL-UAE) and ionic liquid-based aqueous two-phase system (IL-ATPS) was developed for the extraction and purification of secoisolariciresinol diglucoside (SDG) from flaxseed. In the IL-UAE step, several kinds of ILs were investigated as the extractants, to identify the IL that affords the optimum extraction yield. The extraction conditions such as IL concentration, ultrasonic irradiation time, and liquid-solid ratio were optimized using response surface methodology (RSM). In the IL-ATPS step, ATPS formed by adding kosmotropic salts to the IL extract was used for further separation and purification of SDG. The most influential parameters (type and concentration of salt, temperature, and pH) were investigated to obtain the optimum extraction efficiency. The maximum extraction efficiency was 93.35% under the optimal conditions of 45.86% (w/w) IL and 8.27% (w/w) Na2SO4 at 22 °C and pH 11.0. Thus, the combination of IL-UAE and IL-ATPS makes up a simple and effective methodology for the extraction and purification of SDG. This process is also expected to be highly useful for the extraction and purification of bioactive compounds from other important medicinal plants.

Millimeter wave gesture recognition using multi-feature fusion models in complex scenes.

As a form of body language, the gesture plays an important role in smart homes, game interactions, and sign language communication, etc. The gesture recognition methods have been carried out extensively. The existing methods have inherent limitations regarding user experience, visual environment, and recognition granularity. Millimeter wave radar provides an effective method for the problems lie ahead gesture recognition because of the advantage of considerable bandwidth and high precision perception. Interfering factors and the complexity of the model raise an enormous challenge to the practical application of gesture recognition methods as the millimeter wave radar is applied to complex scenes. Based on multi-feature fusion, a gesture recognition method for complex scenes is proposed in this work. We collected data in variety places to improve sample reliability, filtered clutters to improve the signal's signal-to-noise ratio (SNR), and then obtained multi features involves range-time map (RTM), Doppler-time map (DTM) and angle-time map (ATM) and fused them to enhance the richness and expression ability of the features. A lightweight neural network model multi-CNN-LSTM is designed to gestures recognition. This model consists of three convolutional neural network (CNN) for three obtained features and one long short-term memory (LSTM) for temporal features. We analyzed the performance and complexity of the model and verified the effectiveness of feature extraction. Numerous experiments have shown that this method has generalization ability, adaptability, and high robustness in complex scenarios. The recognition accuracy of 14 experimental gestures reached 97.28%.

Bulk transparent supramolecular glass enabled by host-guest molecular recognition.

Supramolecular glass is a non-covalently cross-linked amorphous material that exhibits excellent optical properties and unique intrinsic structural features. Compared with artificial inorganic/organic glass, which has been extensively developed, supramolecular glass is still in the infancy stage, and itself is rarely recognized and studied thus far. Herein, we present the development of the host-guest molecular recognition motifs between methyl-ß-cyclodextrin and para-hydroxybenzoic acid as the building blocks of supramolecular glass. Non-covalent polymerization resulting from the host-guest complexation and hydrogen bonding formation enables high transparency and bulk state to supramolecular glass. Various advantages, including recyclability, compatibility, and thermal processability, are associated with dynamic assembly pattern. Short-range order (host-guest complexation) and long-range disorder (three dimensional polymeric network) structures are identified simultaneously, thus demonstrating the typical structural characteristics of glass. This work provides a supramolecular strategy for constructing transparent materials from organic components.

Smart Microneedle Arrays Integrating Cell-Free Therapy and Nanocatalysis to Treat Liver Fibrosis.

Liver fibrosis is a chronic pathological condition lacking specific clinical treatments. Stem cells, with notable potential in regenerative medicine, offer promise in treating liver fibrosis. However, stem cell therapy is hindered by potential immunological rejection, carcinogenesis risk, efficacy variation, and high cost. Stem cell secretome-based cell-free therapy offers potential solutions to address these challenges, but it is limited by low delivery efficiency and rapid clearance. Herein, an innovative approach for in situ implantation of smart microneedle (MN) arrays enabling precisely controlled delivery of multiple therapeutic agents directly into fibrotic liver tissues is developed. By integrating cell-free and platinum-based nanocatalytic combination therapy, the MN arrays can deactivate hepatic stellate cells. Moreover, they promote excessive extracellular matrix degradation by more than 75%, approaching normal levels. Additionally, the smart MN arrays can provide hepatocyte protection while reducing inflammation levels by ≈70-90%. They can also exhibit remarkable capability in scavenging almost 100% of reactive oxygen species and alleviating hypoxia. Ultimately, this treatment strategy can effectively restrain fibrosis progression. The comprehensive in vitro and in vivo experiments, supplemented by proteome and transcriptome analyses, substantiate the effectiveness of the approach in treating liver fibrosis, holding immense promise for clinical applications.

Yield strength of human erythrocyte membranes to impulsive stretching.

Deformability while remaining viable is an important mechanical property of cells. Red blood cells (RBCs) deform considerably while flowing through small capillaries. The RBC membrane can withstand a finite strain, beyond which it ruptures. The classical yield areal strain of 2-4% for RBCs is generally accepted for a quasi-static strain. It has been noted previously that this threshold strain may be much larger with shorter exposure duration. Here we employ an impulse-like forcing to quantify this yield strain of RBC membranes. In the experiments, RBCs are stretched within tens of microseconds by a strong shear flow generated from a laser-induced cavitation bubble. The deformation of the cells in the strongly confined geometry is captured with a high-speed camera and viability is successively monitored with fluorescence microscopy. We find that the probability of cell survival is strongly dependent on the maximum strain. Above a critical areal strain of ∼40%, permanent membrane damage is observed for 50% of the cells. Interestingly, many of the cells do not rupture immediately and exhibit ghosting, but slowly obtain a round shape before they burst. This observation is explained with structural membrane damage leading to subnanometer-sized pores. The cells finally lyse from the colloidal osmotic pressure imbalance.

Extraction and purification of anthraquinones derivatives from Aloe vera L. using alcohol/salt aqueous two-phase system.

An alcohol/salt aqueous two-phase system (ATPS) composed of 1-propanol and (NH4)2SO4 was employed to purify anthraquinones (AQs) extracted from Aloe vera L. The main influencing system parameters such as type of alcohol, type and concentration of salt, temperature and pH were investigated in detail. Under the optimal extraction conditions, AQs can be extracted into alcohol-rich phase with high extraction efficiency, meanwhile majority polysaccharides, proteins, mineral substances and other impurities were extracted into salt-rich phase. Partitioning of AQs is dependent on hydrophobic interaction, hydrogen bond interaction, and salting-out effect in ATPS. Temperature also played a great role in the partitioning. After ATPS extraction, alcohol can be recycled by evaporation; moreover, salt can be recycled by dilution crystallization method. Compared with other liquid-liquid extractions, this alcohol/salt system is much simpler, lower in cost with easier recovery of phase-forming components, which has the potential scale-up in down-processing of active ingredients in plant.

Bulk and transparent supramolecular glass from evaporation-induced noncovalent polymerization of nucleosides.

Understanding the nature of glass is one of the most important challenges in chemistry, physics, and materials science. In this study, transparent bulk supramolecular glasses with excellent optical behaviors and good mechanical properties were fabricated via the non-covalent polymerization of nucleosides. Hydrogen bonding is the main driving force in the formation of bulk supramolecular glasses. The directional and saturated character of hydrogen bonding enables the formation of a short-range ordered structure, while the weak nature and reversibility of hydrogen bonds allow for the asymmetric and random connections of the short-range ordered structure into a long-range disordered network. Various relaxations, including ß, γ, and δ relaxations, are observed at temperatures below the glass transition temperature, demonstrating the metastable nature of bulk supramolecular glasses. This investigation offers supramolecular insights into the nature of glass materials.