Effects of isoprene on the ozonolysis of Δ3-carene and ß-caryophyllene: Mechanisms of secondary organic aerosol formation and cross-dimerization.

Elucidating the mutual effects between the different volatile organic compounds (VOCs) is crucial for comprehending the formation mechanism of atmospheric secondary organic aerosols (SOA). Here, the mixed VOCs experiments of isoprene and Δ3-carene/ß-caryophyllene were carried out in the presence of O3 using an indoor smog chamber. The suppression effect of isoprene was recognized by the scanning mobility particle sizer spectrometer, online vacuum ultraviolet free electron laser (VUV-FEL) photoionization aerosol mass spectrometry, and quantum chemical calculations. The results indicate that the suppression effect of isoprene on the ozonolysis of Δ3-carene and ß-caryophyllene shows fluctuating and monotonous trends, respectively. The carbon content of the precursor could be the main factor for regulating the strength of the suppression effect. Plausible structures and formation mechanisms of several new products generated from the single VOC precursor and VOC-cross-reaction are proposed, which enrich the category of VOC oxidation products. Meanwhile, a new dimerization mechanism of the RO2 + R'O2 reaction is suggested, which offers an intriguing perspective on the gas phase formation process of particle phase accretion products. The present findings provide valuable insights into clarifying the pivotal roles played by isoprene in the interplay between different VOCs and understanding of SOA formation mechanisms of VOC mixtures, especially nearby the emission origins.

Assessment of the carcinogenic potential of particulate matter generated from 3D printing devices in Balb/c 3T3-1-1 cells.

Recently, there have been reports of sarcoma occurring in a Korean science teachers who used a 3D printer with acrylonitrile butadiene styrene (ABS) and polylactic acid (PLA) filaments for educational purposes. However, limited toxicological research data on 3D printing make it challenging to confirm a causal relationship between 3D printing and cancer. Therefore, occupational accidents involving teachers who have developed sarcoma have not been officially recognized. To address this gap, we aimed to evaluate the carcinogenic potential of particulate matter produced from ABS and PLA filaments commonly used in 3D printing. We created a generator mimicking 3D printing to generate particulate matter, which was used as an experimental material. The collected particulate matter was exposed to an in vitro system to investigate genetic damage, effects on cell transformation, and changes in carcinogenesis-related genes. Various assays, such as the comet assay, cell transformation assays, microarray analysis, and glucose consumption measurement, were employed. Cytotoxicity tests performed to determine the exposure concentration for the comet assay showed that cell viability was 83.6, 62.6, 42.0, and 10.2% for ABS at exposure concentrations of 50, 100, 200, and 400 µg/mL, respectively. PLA showed 91.7, 80.3, 65.1, and 60.8% viability at exposure concentrations of 50, 100, 200, and 400 µg/mL, respectively. Therefore, 50 µg/mL was set as the highest concentration for both ABS and PLA, and 25 and 12.5 µg/mL were set as the medium and low concentrations, respectively. The comet assay showed no changes in genetic damage caused by the particulate matter. Cytotoxicity results performed to establish exposure concentrations in the transformation assay showed that ABS showed cell viability of 88.0, 77.4, 84.7, and 85.5% at concentrations of 1.25, 2.5, 5, and 10 µg/mL, respectively, but few cells survived at concentrations above 20 µg/mL. PLA showed minimal cytotoxicity up to a concentration of 20 µg/ml. Therefore, in the cell transformation assay, a concentration of 10 µg/mL for ABS and 20 µg/mL for PLA was set as the highest exposure concentration, followed by medium and low exposure concentrations with a common ratio of 2. In cell transformation assays, only one transformed focus each was observed for both ABS and PLA particulate matter-exposed cells. The microarray assay revealed changes in gene expression, with a 41.7% change at 10 µg/mL for ABS and an 18.6% change at 20 µg/mL for PLA compared to the positive control group. Analysis of carcinogenesis-related gene expression changes on days 1, 7, and 25 of the promotion phase revealed that in cells exposed to 5 µg/mL of ABS, RBM3 gene expression increased by 3.66, 3.26, and 3.74 times, respectively, while MPP6 gene expression decreased by 0.33, 0.28, and 0.38 times, respectively, compared to the negative control group. Additionally, the measurement of glucose consumption showed that it increased in cells exposed to ABS and PLA particulate matter. Our findings suggest that the carcinogenic potential of ABS- and PLA-derived particulate matter in 3D printing cannot be completely ruled out. Therefore, further research in other test systems and analysis of additional parameters related to carcinogenesis, are deemed necessary to evaluate the carcinogenic risk of 3D printers using these materials.

Prediction of Acrylonitrile-Butadiene-Styrene Mechanical Properties through Compressed-Sensing Techniques.

One of the challenges in the plastic industry is the cost and time spent on the characterization of different grades of polymers. Compressed sensing is a data reconstruction method that combines linear algebra with optimization schemes to retrieve a signal from a limited set of measurements of that signal. Using a data set of signal examples, a tailored basis can be constructed, allowing for the optimization of the measurements that should be conducted to provide the highest and most robust signal reconstruction accuracy. In this work, compressed sensing was used to predict the values of numerous properties based on measurements for a small subset of those properties. A data set of 21 fully characterized acrylonitrile-butadiene-styrene samples was used to construct a tailored basis to determine the minimal subset of properties to measure to achieve high reconstruction accuracy for the remaining nonmeasured properties. The analysis showed that using only six measured properties, an average reconstruction error of less than 5% can be achieved. In addition, by increasing the number of measured properties to nine, an average error of less than 3% was achieved. Compressed sensing enables experts in academia and industry to substantially reduce the number of properties that must be measured to fully and accurately characterize plastics, ultimately saving both costs and time. In future work, the method should be expanded to optimize not only individual properties but also entire tests used to simultaneously measure multiple properties. Furthermore, this approach can also be applied to recycled materials, of which the properties are more difficult to predict.

Long-term contributions of VOC sources and their link to ozone pollution in Bronx, New York City.

Changes in energy and environmental policies along with changes in the energy markets of New York State over the past two decades, have spurred interest in evaluating their impacts on emissions from various energy generation sectors. This study focused on quantifying these effects on VOC (volatile organic compounds) emissions and their subsequent impacts on air quality within the New York City (NYC) metropolitan area. NYC is an EPA nonattainment region for ozone (O3) and likely is a VOC limited region. NYC has a complex coastal topography and meteorology with low-level jets and sea/bay/land breeze circulation associated with heat waves, leading to summertime O3 exceedances and formation of secondary organic aerosol (SOA). To date, no comprehensive source apportionment studies have been done to understand the contributions of local and long-range sources of VOCs in this area. This study applied an improved Positive Matrix Factorization (PMF) methodology designed to incorporate atmospheric dispersion and photochemical reaction losses of VOCs to provide improved apportionment results. Hourly measurements of VOCs were obtained from a Photochemical Assessment Monitoring Station located at an urban site in the Bronx from 2000 to 2021. The study further explores the role of VOC sources in O3 and SOA formation and leverages advanced machine learning tools, XGBoost and SHAP algorithms, to identify synergistic interactions between sources and provided VOC source impacts on ambient O3 concentrations. Isoprene demonstrated a substantial influence in the source contribution of the biogenic factor, emphasizing its role in O3 formation. Notable contributions from anthropogenic emissions, such as fuel evaporation and various industrial processes, along with significant traffic-related sources that likely contribute to SOA formation, underscore the combined impact of natural and human-made sources on O3 pollution. Findings of this study can assist regulatory agencies in developing appropriate policy and management initiatives to control O3 pollution in NYC.

Unraveling the effects of acrylonitrile butadiene styrene (ABS) microplastic ageing on the sorption and toxicity of ionic liquids with 2,4-D and glyphosate herbicides.

Microplastics represent a novel category of environmental pollutants, and understanding their interactions with typical xenobiotics is crucial. In this study, we investigated the impact of ionic liquids (ILs) containing herbicidal anions, namely glyphosate [Glyph] and 2,4-dichlorophenoxyacetate [2,4-D], and the surfactant cation - dodecyltrimethylammonium [C12TMA] on acrylonitrile butadiene styrene (ABS) microplastics. The aim of the study was to assess the sorption capacity of microplastics that were present in both untreated and aged form using standard and modified Fenton methods. In addition, impact on toxicity and stress adaptation of the model soil bacterium Pseudomonas putida KT2440 was measured. Upon ageing, ABS microplastics underwent a fivefold increase in BET surface area and total pore volume (from 0.001 to 0.004 cm3/g) which lead to a dramatic increase in adsorption of the cations on ABS microplastics from 40 to 45% for virgin ABS to 75-80% for aged ABS. Toxicity was mainly attributed to hydrophobic cations in ILs (EC50 ∼ 60-65 mg/dm3), which was also mitigated by sorption on ABS. Furthermore, both cations and anions behaved similarly across different ILs, corresponding chlorides, and substrates used in the ILs synthesis. These findings highlight microplastics potential as hazardous sorbents, contributing to the accumulation of xenobiotics in the environment.

Synthesis and characterization of the trans- and cis-isomers of N-acetyl-S-(4-hydroxy-2-buten-1-yl)-L-cysteine and their attempted detection in human urine.

1,3-Butadiene (BD) is a carcinogenic air pollutant. N-acetyl-S-(4-hydroxy-2-buten-1-yl)-L-cysteine (MHBMA3 or 4HBeMA), an urinary BD metabolite with unspecified configuration, is considered the most sensitive BD biomarker and has been used in routine biomonitoring since 2012. However, two issues remain unaddressed: why its concentrations are unusually high relative to other urinary BD biomarkers and why some authors reported no detection of the biomarker whereas other authors readily quantitated it. To address the issues, we synthesized and structurally characterized the authentic trans- and cis-isomers of MHBMA3 (designated NE and NZ, respectively), developed an isotope-dilution LC-MS/MS method for their quantification, and examined 67 urine samples from barbecue restaurant personnel (n = 47) and hotel administrative staff (n = 20). The restaurant personnel were exposed to barbecue fumes, which contain relatively high concentrations of BD. The results showed that NE and NZ had highly similar NMR spectra, and were difficult to be well separated chromatographically. The NMR data showed that the MHBMA3 isomer investigated in most previous studies was NE. We did not detect NE and NZ in any samples; however, an interfering peak with varying heights was observed in most samples. Notably, under the chromatographic conditions used in the literature, the peak exhibited indistinguishable retention time from that of NE. Thus, it is highly likely that the interfering peak has been mis-identified as NE in previous studies, providing a reasonable explanation for the high MHBMA3 concentration in urine. The contradiction in the presence of MHBMA3 in urine was also caused by the mis-identification, because the researchers who reported the absence of MHBMA3 were actually detecting NZ. Thus, we clarified the confusion on MHBMA3 in previous studies through correctly identifying the two MHBMA3 isomers. The presence of NE and NZ in human urine warrants further investigations.

Evaluating exposure-response relationship in 1,3-butadiene and leukemia studies.

OBJECTIVES: 1,3-Butadiene (BD) exposure's link to leukemia is under regulatory scrutiny. The assessment methods for BD exposure risks have evolved from early animal and limited human studies to advanced exposure-response modelling with comprehensive quantitative data. The objec- tive of this study is to explore the nuances of exposure-response modelling, investigating how various statistical methods have influenced the quan- tification of exposure-response relationships. MATERIAL AND METHODS: Although this study was not conducted as a formal systematic review, a search was performed in Medline/Pubmed to identify all human studies on leukemia risk assessment for BD exposure. This search included articles written in English. The electronic search spanned from inception of records until July 23, 2023, using the search term: "butadiene AND (leukaemia OR leukemia OR myeloid OR lymphoid)" and was restricted to human species. Focusing on the synthetic styrene-butadiene rubber (SBR) industry cohort study conducted by the University of Alabama at Birmingham, USA, this review evaluates various statistical models and factors influenc- ing exposure-response modelling. RESULTS: Peak exposures to BD may be more influential in the dose-response relationship than cumulative or long-term exposure. The authors recommend utilizing ß-coefficients derived from the latest SBR study update, employing Cox proportional hazard modelling, non-lagged and non-transformed cumulative BD exposure, and adjusting for age and peak BD exposure. The study reveals that statistical model selection has a limited impact on the calculated dose-response effects. The significant variation in estimated cancer mortality values arises from additional assumptions needed for metrics like the excess leukemia risk or the occupational BD effective concentration. CONCLUSIONS: In con- clusion, this study provides insights into exposure-response modelling for BD exposure and leukemia mortality, highlighting the importance of peak exposures. The recommended statistical approach offers a reliable basis for regulatory risk assessment and public health population metrics. Int J Occup Med Environ Health. 2024;37(3):300-10.

Investigating the Effect of Chain Extender on the Phase Separation and Mechanical Properties of Polybutadiene-Based Polyurethane.

The thermodynamic incompatibility between the soft and hard segments of thermoplastic polyurethane (TPU) results in a microphase-separated behavior and excellent mechanical properties. However, the effect of the chain extender on the degree of microphase separation (DMS) and the resultant mechanical properties of TPU have not been well studied because of the complex interactions between the soft and hard segments. Herein, hydroxyl-terminated polybutadiene-based TPUs(HTPB-TPUs) without hydrogen bonding between the soft and hard segments are synthesized using hydroxyl-terminated polybutadiene, toluene diisocyanate, and four different chain extenders, and the effect of the chain extender structure on DMS is analyzed experimentally using a combination of analytical techniques. Furthermore, the solubility parameters of the soft and hard segments, glass transition temperatures, and hydrogen-bond density of the HTPB-TPUs, are computed using all-atom molecular dynamics simulations. The results clearly reveal that the chain extender significantly affects the DMS and thus the mechanical properties of HTPB-TPUs. This study paves the way for studying the relationship between the structure and properties of TPU.

Characterisation of 3D-printable thermoplastics to be used as tissue-equivalent materials in photon and proton beam radiotherapy end-to-end quality assurance devices.

Objective.To investigate the potential of 3D-printable thermoplastics as tissue-equivalent materials to be used in multimodal radiotherapy end-to-end quality assurance (QA) devices.Approach.Six thermoplastics were investigated: Polylactic Acid (PLA), Acrylonitrile Butadiene Styrene (ABS), Polyethylene Terephthalate Glycol (PETG), Polymethyl Methacrylate (PMMA), High Impact Polystyrene (HIPS) and StoneFil. Measurements of mass density (ρ), Relative Electron Density (RED), in a nominal 6 MV photon beam, and Relative Stopping Power (RSP), in a 210 MeV proton pencil-beam, were performed. Average Hounsfield Units (HU) were derived from CTs acquired with two independent scanners. The calibration curves of both scanners were used to predict averageρ,RED and RSP values and compared against the experimental data. Finally, measured data ofρ,RED and RSP was compared against theoretical values estimated for the thermoplastic materials and biological tissues.Main results.Overall, goodρand RSP CT predictions were made; only PMMA and PETG showed differences >5%. The differences between experimental and CT predicted RED values were also <5% for PLA, ABS, PETG and PMMA; for HIPS and StoneFil higher differences were found (6.94% and 9.42/15.34%, respectively). Small HU variations were obtained in the CTs for all materials indicating good uniform density distribution in the samples production. ABS, PLA, PETG and PMMA showed potential equivalency for a variety of soft tissues (adipose tissue, skeletal muscle, brain and lung tissues, differences within 0.19%-8.35% for all properties). StoneFil was the closest substitute to bone, but differences were >10%. Theoretical calculations of all properties agreed with experimental values within 5% difference for most thermoplastics.Significance.Several 3D-printed thermoplastics were promising tissue-equivalent materials to be used in devices for end-to-end multimodal radiotherapy QA and may not require corrections in treatment planning systems' dose calculations. Theoretical calculations showed promise in identifying thermoplastics matching target biological tissues before experiments are performed.

Responses of plant volatile emissions to increasing nitrogen deposition: A pilot study on Eucalyptus urophylla.

Biogenic volatile organic compounds (BVOCs) significantly impact atmospheric chemistry, with emissions potentially influenced by nitrogen (N) deposition. The response of BVOC emissions to increasing N deposition remains debated. In this study, we examined Eucalyptus urophylla (E. urophylla) using three N treatments: N0, N50, and N100 (0, 50, and 100 kg N hm-2 yr-1 N addition). These treatments were applied to mature E. urophylla trees in a plantation subjected to over 10 years of soil N addition in southern China, a region with severe N deposition. Seventeen BVOCs were measured, with isoprene (36.99 %), α-pinene (38.80 %), and d-limonene (14.27 %) being the predominant compounds under natural conditions. Total BVOC emissions under N50 were nearly double those under N0 and N100, with leaf net CO2 assimilation identified as the most critical photosynthetic parameter. Isoprene and α-pinene emissions significantly increased under N50 compared to N0, while d-limonene emission decreased under N100. Stronger correlations for individual BVOCs under N50 and N100 compared to N0 might be due to differences in BVOC biosynthetic pathways and storage structures. The localized canopy-scale emission factors (EFs) under N50 were significantly higher than the default values in the Model of Emissions of Gases and Aerosols from Nature (MEGAN), suggesting the model might underestimate BVOC emissions from Eucalyptus in southern China under increased N deposition. Additionally, the secondary pollutant formation potentials of BVOCs were evaluated, identifying isoprene and monoterpenes as primary precursors of ozone and secondary organic aerosols. This study provides insights into the impacts of increased N deposition on BVOC emissions and their contribution to secondary atmospheric pollution. Updating localized BVOC EFs for subtropical tree species in southern China is crucial to reduce uncertainties in BVOC estimations under current and future N deposition scenarios.

The BDNF-ERK/MAPK axis reduces phosphatase and actin regulator1, 2 and 3 (PHACTR1, 2 and 3) mRNA expressions in cortical neurons.

Actin rearrangement and phosphorylation-dephosphorylation in the nervous system contribute to plastic alteration of neuronal structure and function. Phosphatase and actin regulator (PHACTR) family members are actin- and protein phosphatase 1 (PP1)-binding proteins. Because some family members act as regulators of neuronal morphology, studying the regulatory mechanisms of PHACTR is valuable for understanding the basis of neuronal circuit formation. Although expression patterns of PHACTR family molecules (PHACTR1-4) vary across distinct brain areas, little is known about the extracellular ligands that influence their mRNA levels. In this study, we focused on an important neurotrophin, brain-derived neurotrophic factor (BDNF), and examined its effect on mRNA expression of PHACTR family member in cortical neurons. PHACTR1-3, but not PHACTR4, were affected by stimulation of primary cultured cortical neurons with BDNF; namely, sustained downregulation of their mRNA levels was observed. The observed downregulation was blocked by an inhibitor of the extracellular signal-regulated protein kinase/mitogen-activated protein kinase (ERK/MAPK) pathway, U0126, suggesting that ERK/MAPK plays an inhibitory role for gene induction of PHACTR1-3. These findings aid the elucidation of how BDNF regulates actin- and PP1-related neuronal functions.

Impact of severe drought on biogenic volatile organic compounds emissions from Sphagnum mosses in boreal peatlands.

Climate change and the associated increased frequency of extreme weather events are likely to alter the emissions of biogenic volatile organic compounds (BVOCs) from boreal peatlands. Hydrologically sensitive Sphagnum mosses are keystone species in boreal peatland ecosystems that are known to emit various BVOCs. However, it is not known how their emissions respond to seasonal droughts. In this study, we quantified the effect of severe drought, and subsequent recovery, on the BVOC emissions from Sphagnum mosses using mesocosms originating from wet open and naturally drier treed boreal fens and bogs. Here we report the emissions of 30 detected BVOCs, of which isoprene was the most abundant with an average flux rate of 5.6 µg m-2 h-1 (range 0-31.9 µg m-2 h-1). The experimental 43-day ecohydrological drought reduced total BVOC and isoprene emissions. In addition, in mesocosms originating from bogs, sesquiterpene emissions decreased with the drought, while the emissions of green leaf volatiles were induced. Sesquiterpene emissions remained low even six weeks after rewetting, indicating a long and limited recovery from the drought. Our results further imply that long-term exposure to deep water tables does not decrease sensitivity of Sphagnum to an extreme drought; we did not detect differences in the emission rates or drought responses between Sphagna originating from wet open and naturally drier treed habitats. Yet, the differences between fen and bog originating Sphagna indicate local variability in the BVOC quality changes following drought, potentially altering the climate feedback of boreal peatland BVOC emissions.

Hysteresis-Free Temperature Sensing with Printable Electronic Skins Made of Liquid Polyisoprene/CNTs.

Developing an electronic skin (e-skin) is becoming popular due to its capability to mimic human skin's ability to detect various stimuli. Mostly, such skins are tactile-based sensors. However, the exploration of nontactile-based sensing capability in the e-skin is still in a nascent stage. Herein, we report an approach toward developing electrical hysteresis- and cross-interference-free nontactile e-skin using liquid polyisoprene with an ultralow concentration of multiwalled carbon nanotubes (ϕ = 0.006 volume fraction) by leveraging the stencil printing technique. The impact of cross-linking the samples was studied. Uncross-linked samples demonstrated higher electrical conductivity than the cross-linked samples. A coarse-grained phenomenological model with molecular dynamics simulation was utilized to investigate filler network formation and percolation that dictate the conductivity of uncross-linked and cross-linked samples. Simulation studies supported the fidelity of the experimental findings. The uncross-linked e-skin demonstrated a higher temperature sensitivity (-1.103%/°C) than the cross-linked e-skin (-0.320%/°C) in the thermal conduction mode. Despite the superior sensitivity of the uncross-linked e-skin, the cross-linked systems demonstrated superior cyclic stability (35 thermal cycles), ensuring reliable sensor readings over extended usage. Judicious choice of encapsulant warranted the cross-linked e-skin sensor to nullify the impact of moisture on signal output, thereby providing cross-interference-free results. The optimized e-skin sample retained a similar thermal sensitivity even when used in the nontactile mode. From the application purview, the utility of the developed sensor was tested successfully for nontactile sensing of human body temperature. Additionally, the sensor was utilized to determine the respiratory profile by integrating the developed sensor into a wearable mask. This study advances nontactile e-skin-based sensing technology and opens new avenues for creating wearable and IoT devices for healthcare and human-machine interactions.

Remote liver ischemic preconditioning protects against renal ischemia/reperfusion injury via phosphorylation of extracellular signal-regulated kinases 1 and 2 in mice.

Perioperative acute kidney injury (AKI), which is mainly mediated by renal ischemia‒reperfusion (I/R) injury, is commonly observed in clinical practice. However, effective measures for preventing and treating this perioperative complication are still lacking in the clinic. Thus, we designed this study to examine whether remote liver ischemic preconditioning (RLIPC) has a protective effect on damage caused by renal I/R injury. In a rodent model, 30 mice were divided into five groups to assess the effects of RLIPC and ERK1/2 inhibition on AKI. The groups included the sham-operated (sham), kidney ischemia and reperfusion (CON), remote liver ischemic preconditioning (RLIPC), CON with the ERK1/2 inhibitor U0126 (CON+U0126), and RLIPC with U0126 (RLIPC+U0126). RLIPC consisted of 4 liver ischemia cycles before renal ischemia. Renal function and injury were assessed through biochemical assays, histology, cell apoptosis and protein phosphorylation analysis. RLIPC significantly mitigated renal dysfunction, tissue damage, inflammation, and apoptosis caused by I/R, which was associated with ERK1/2 phosphorylation. Furthermore, ERK1/2 inhibition with U0126 negated the protective effects of RLIPC and exacerbated renal injury. To summarize, we demonstrated that RLIPC has a strong renoprotective effect on kidneys post I/R injury and that this effect may be mediated by phosphorylation of ERK1/2.

The role of cytokine receptor-like factor 1 (CRLF1) in facet joint osteoarthritis pathogenesis.

BACKGROUND: Facet joint osteoarthritis (FJOA) is a prevalent condition contributing to low back pain, particularly in the elderly population. This study aimed to investigate the potential role of Cytokine Receptor-like Factor 1 (CRLF1) in FJOA pathogenesis and its therapeutic implications. METHODS: Bioinformatics analysis was utilized to identify CRLF1 as the target gene, followed by quantification of CRLF1 expression levels and joint degeneration degree using immunohistochemistry (IHC). In primary chondrocytes, the inhibition of CRLF1 expression by siRNA was performed, and Western blot analysis was conducted to evaluate the involvement of the extracellular matrix and MAPK/ERK signaling pathway. Flow cytometry was employed to assess the apoptosis rate of chondrocytes, while immunofluorescence (IF) was utilized to evaluate the localization of CRLF1, cleaved-caspase3, MMP13, COL2A1, and ERK. RESULTS: The expression of CRLF1 was found to be significantly elevated in FJOA tissues compared to normal tissues. Through the use of loss-of-function assays, it was determined that CRLF1 not only enhanced the rate of apoptosis in chondrocytes, but also facilitated the degradation of the extracellular matrix in vitro. Furthermore, CRLF1 was found to activate the ERK1/2 pathways. The pro-arthritic effects elicited by CRLF1 were mitigated by treatment with the MEK inhibitor U0126 in chondrocytes. CONCLUSION: These results suggest that CRLF1 enhances chondrocytes apoptosis and extracellular matrix degration in FJOA and thus may therefore be a potential therapeutic target for FJOA.

Smart-Adhesive, Breathable and Waterproof Fibrous Electronic Skins.

For the need of direct contact with the skin, electronic skins (E-skins) should not only fulfill electric functions, but also ensure comfort during wearing, including permeability, waterproofness, and easy removal. Herein, the study has developed a self-adhesive, detach-on-demand, breathable, and waterproof E-skin (PDSC) for motion sensing and wearable comfort by electrospinning styrene-isoprene block copolymer rubber with carbon black nanosheets as the sensing layer and liner copolymers of N, N-dimethylacrylamide, n-octadecyl acrylate and lauryl methacrylate as the adhesive layer. The high elasticity and microfiber network structure endow the PDSC with good sensitivity and high linearity for strain sensing. The hydrophobic and crystallizable adhesive layer ensures robust, waterproof, and detaching-on-demand skin adhesion. Meanwhile, the fiber structure enables the PDSC good air and water permeability. The integration of electric and wearable functions endows the PDSC with great potential for motion sensing during human activities as both the sensing and wearable performances.

PM10 exposure induces bronchial hyperresponsiveness by upreguating acetylcholine muscarinic 3 receptor.

Exposure to particulate matter (PM10) can induce respiratory diseases that are closely related to bronchial hyperresponsiveness. However, the involved mechanism remains to be fully elucidated. This study aimed to demonstrate the effects of PM10 on the acetylcholine muscarinic 3 receptor (CHRM3) expression and the role of the ERK1/2 pathway in rat bronchial smooth muscle. A whole-body PM10 exposure system was used to stimulate bronchial hyperresponsiveness in rats for 2 and 4 months, accompanied by MEK1/2 inhibitor U0126 injection. The whole-body plethysmography system and myography were used to detect the pulmonary and bronchoconstrictor function, respectively. The mRNA and protein levels were determined by Western blotting, qPCR, and immunofluorescence. Enzyme-linked immunosorbent assay was used to detect the inflammatory cytokines. Compared with the filtered air group, 4 months of PM10 exposure significantly increased CHRM3-mediated pulmonary function and bronchial constriction, elevated CHRM3 mRNA and protein expression levels on bronchial smooth muscle, then induced bronchial hyperreactivity. Additionally, 4 months of PM10 exposure caused an increase in ERK1/2 phosphorylation and increased the secretion of inflammatory factors in bronchoalveolar lavage fluid. Treatment with the MEK1/2 inhibitor, U0126 inhibited the PM10 exposure-induced phosphorylation of the ERK1/2 pathway, thereby reducing the PM10 exposure-induced upregulation of CHRM3 in bronchial smooth muscle and CHRM3-mediated bronchoconstriction. U0126 could rescue PM10 exposure-induced pathological changes in the bronchus. In conclusion, PM10 exposure can induce bronchial hyperresponsiveness in rats by upregulating CHRM3, and the ERK1/2 pathway may be involved in this process. These findings could reveal a potential therapeutic target for air pollution induced respiratory diseases.

The rigid-flexible balanced molecular crosslinking network transition interface: An effective strategy for improving the performance of bamboo fibers/poly(butadiene succinate-co-butadiene adipate) biocomposites.

The poor interfacial compatibility of natural fiber-reinforced polymer composites has become a major challenge in the development of industry-standard high-performance composites. To solve this problem, this study constructs a novel rigid-flexible balanced molecular crosslinked network transition interface in composites. The interface improves the interfacial compatibility of the composites by balancing the stiffness and strength of the fibers and the matrix， effectively improving the properties of the composites. The flexural strength and flexural modulus of the composites were enhanced by 38 % and 44 %, respectively. Water absorption decreased by 30 %. The initial and maximum thermal degradation temperatures increased by 20 °C and 16 °C, respectively. The maximum storage modulus increased by 316 %. Furthermore, the impact toughness was elevated by 41 %, attributed to the crosslinked network's efficacy in absorbing and dissipating externally applied energy. This innovative approach introduces a new theory of interfacial reinforcement compatibility, advancing the development of high-performance and sustainable biocomposites.

Impact of three decades of warming, increased nutrient availability, and increased cloudiness on the fluxes of greenhouse gases and biogenic volatile organic compounds in a subarctic tundra heath.

Climate change is exposing subarctic ecosystems to higher temperatures, increased nutrient availability, and increasing cloud cover. In this study, we assessed how these factors affect the fluxes of greenhouse gases (GHGs) (i.e., methane (CH4), nitrous oxide (N2O), and carbon dioxide (CO2)), and biogenic volatile organic compounds (BVOCs) in a subarctic mesic heath subjected to 34 years of climate change related manipulations of temperature, nutrient availability, and light. GHGs were sampled from static chambers and gases analyzed with gas chromatograph. BVOCs were measured using the push-pull method and gases analyzed with chromatography-mass spectrometry. The soil temperature and moisture content in the warmed and shaded plots did not differ significantly from that in the controls during GHG and BVOC measurements. Also, the enclosure temperatures during BVOC measurements in the warmed and shaded plots did not differ significantly from temperatures in the controls. Hence, this allowed for assessment of long-term effects of the climate treatment manipulations without interference of temperature and moisture differences at the time of measurements. Warming enhanced CH4 uptake and the emissions of CO2, N2O, and isoprene. Increased nutrient availability increased the emissions of CO2 and N2O but caused no significant changes in the fluxes of CH4 and BVOCs. Shading (simulating increased cloudiness) enhanced CH4 uptake but caused no significant changes in the fluxes of other gases compared to the controls. The results show that climate warming and increased cloudiness will enhance CH4 sink strength of subarctic mesic heath ecosystems, providing negative climate feedback, while climate warming and enhanced nutrient availability will provide positive climate feedback through increased emissions of CO2 and N2O. Climate warming will also indirectly, through vegetation changes, increase the amount of carbon lost as isoprene from subarctic ecosystems.

Characterizing Dissipative Elastic Metamaterials Produced by Additive Manufacturing.

Viscoelastic behavior can be beneficial in enhancing the unprecedented dynamics of polymer metamaterials or, in contrast, negatively impacting their wave control mechanisms. It is, therefore, crucial to properly characterize the viscoelastic properties of a polymer metamaterial at its working frequencies to understand viscoelastic effects. However, the viscoelasticity of polymers is a complex phenomenon, and the data on storage and loss moduli at ultrasonic frequencies are extremely limited, especially for additively manufactured polymers. This work presents a protocol to experimentally characterize the viscoelastic properties of additively manufactured polymers and to use them in the numerical analysis of polymer metamaterials. Specifically, the protocol includes the description of the manufacturing process, experimental procedures to measure the thermal, viscoelastic, and mechanical properties of additively manufactured polymers, and an approach to use these properties in finite-element simulations of the metamaterial dynamics. The numerical results are validated in ultrasonic transmission tests. To exemplify the protocol, the analysis is focused on acrylonitrile butadiene styrene (ABS) and aims at characterizing the dynamic behavior of a simple metamaterial made from it by using fused deposition modeling (FDM) three-dimensional (3D) printing. The proposed protocol will be helpful for many researchers to estimate viscous losses in 3D-printed polymer elastic metamaterials that will improve the understanding of material-property relations for viscoelastic metamaterials and eventually stimulate the use of 3D-printed polymer metamaterial parts in various applications.