Association between temporary employment and current smoking and change in smoking behaviors: A prospective cohort study from South Korea (2009-2018).

Background Previous studies have suggested that employment insecurity is associated with adverse health outcomes. We explored the association between temporary employment and smoking behaviors.Methods We analyzed 11,795 workers (51,867 observations) from the Korea Health Panel Study (2009-2018). Employment types were categorized as regular, fixed-term, or daily, based on the duration of labor contract. The outcomes were current smoking status and changes in smoking behavior (initiation or cessation) in the following year. Generalized estimating equations were used to estimate odds ratio (OR) and 95% confidence interval (CI).Results The proportions of fixed-term and daily workers were 41.2% and 16.4% for women and 23.6% and 12.4% for men, respectively. Temporary employment was associated with increased odds of current smoking, while also demonstrating prospective associations with changes in smoking behaviors. For instance, in prospective analyses, male workers with fixed-term and daily employments were associated with a decreased likelihood of smoking cessation (OR:0.77; 95% CI:0.65-0.91 for fixed-term employment and OR:0.66; 95% CI:0.52-0.83 for daily employment) in the following year compared to those with regular employment. Moreover, those experiencing consecutive temporary employment was most inversely associated with smoking cessation in both men (OR:0.56; 95% CI:0.44-0.71) and women (OR:0.37; 95% CI:0.16-0.85) compared to those experiencing consecutive regular employment. However, no clear association between temporary employment and smoking initiation was observed in both men and women.Conclusions Temporary employment is directly associated with current smoking and inversely associated with smoking cessation. Policies are needed to improve job insecurity among temporary employees.

Association between sickness presenteeism and depressive symptoms: a cross-sectional study using the 6th Korean working conditions survey.

PURPOSE: This study aimed to reveal the relationship of the days of experiencing sickness presentism and depressive symptoms among Korean workers. Sickness presenteeism which defined as the act of going to work despite being feeling unhealthy triggers various adverse effects on mental health, including increased risks of depression. Furthermore, Sickness presenteeism is a major social issue causing substantial socioeconomic costs. METHODS: The data of 25120 participants from sixth Korean Working Condition Survey was utilized in this cross-sectional study. Sickness presenteeism was defined using a self-reported questionnaire and depressive symptoms were assessed by WHO well-being index. Multivariate logistic regression analysis was conducted to calculate the odd ratios for depressive symptoms regarding the number of days experiencing sickness presenteeism. We calculated odds ratios (ORs) and 95% confidence interval (95% CI) for depressive symptoms after categorizing participants into three groups based on the duration of experiencing sickness presenteeism, using cut-off values of 3 and 5 days. RESULTS: Workers who have experienced sickness presenteeism for more than 5 days were at highest risk for depressive symptoms than referent group (OR 2.87; 95% CI 2.17-3.76 in male, OR 3.86; 95% CI 3.02-4.91 in female). Furthermore, there was a trend of increasing risk for depressive symptom as the duration of experiencing sickness presenteeism extended. CONCLUSION: This study presents the association between experiencing sickness presenteeism in the previous 12 months and depressive symptoms. Based on the results, we provide individual and organizational strategies of reducing sickness presenteeism. Also, screening for workers who have experienced sickness presenteeism are needed to ensure good mental health.

Development strategy of non-GMO organism for increased hemoproteins in Corynebacterium glutamicum: a growth-acceleration-targeted evolution.

Heme, found in hemoproteins, is a valuable source of iron, an essential mineral. The need for an alternative hemoprotein source has emerged due to the inherent risks of large-scale livestock farming and animal proteins. Corynebacterium glutamicum, regarded for Qualified Presumption of Safety or Generally Recognized as Safe, can biosynthesize hemoproteins. C. glutamicum single-cell protein (SCP) can be a valuable alternative hemoprotein for supplying heme iron without adversely affecting blood fat levels. We constructed the chemostat culture system to increase hemoprotein content in C. glutamicum SCP. Through adaptive evolution, hemoprotein levels could be naturally increased to address oxidative stress resulting from enhanced growth rate. In addition, we used several specific plasmids containing growth-accelerating genes and the hemA promoter to expedite the evolutionary process. Following chemostat culture for 15 days, the plasmid in selected descendants was cured. The evolved strains showed improved specific growth rates from 0.59 h-1 to 0.62 h-1, 20% enhanced resistance to oxidative stress, and increased heme concentration from 12.95 µg/g-DCW to 14.22-15.24 µg/g-DCW. Notably, the putative peptidyl-tRNA hydrolase-based evolved strain manifested the most significant increase (30%) of hemoproteins. This is the first report presenting the potential of a growth-acceleration-targeted evolution (GATE) strategy for developing non-GMO industrial strains with increased bio-product productivity.

Two-Dimensional Peptide Assembly via Arene-Perfluoroarene Interactions for Proliferation and Differentiation of Myoblasts.

Supramolecular assembly based on aromatic interactions can provide well-defined nanostructures with an understanding of intermolecular interactions at the molecular level. The peptide assembly via a supramolecular approach can overcome the inherent limitations of bioactive peptides, such as proteolytic degradations and rapid internalizations into the cytosol. Although extensive research has been carried out on supramolecular peptide materials with a two-dimensional (2D) structure, more needs to be reported on biological activity studies using well-defined 2D peptide materials. Physical and chemical properties of the 2D peptide assembly attributed to their large surface area and flexibility can show low cytotoxicity, enhanced molecular loading, and higher bioconjugation efficiency in biological applications. Here, we report supramolecular 2D materials based on the pyrene-grafted amphiphilic peptide, which contains a peptide sequence (Asp-Gly-Glu-Ala; DGEA) that is reported to bind to the integrin α2ß1 receptor in 2D cell membranes. The addition of octafluoronaphthalene (OFN) to the pyrene-grafted peptide could induce a well-ordered 2D assembly by face-centered arene-perfluoroarene stacking. The DGEA-peptide 2D assembly with a flat structure, structural stability against enzymatic degradations, and a larger size can enhance the proliferation and differentiation of muscle cells via continuous interactions with cell membrane receptors integrin α2ß1 showing a low intracellular uptake (15%) compared to that (62%) of the vesicular peptide assembly. These supramolecular approaches via the arene-perfluoroarene interaction provide a strategy to fabricate well-defined 2D peptide materials with an understanding of assembly at the molecular level for the next-generation peptide materials.

Coherent Vibronic Wavepackets Show Structure-Directed Charge Flow in Host-Guest Donor-Acceptor Complexes.

Designing and controlling charge transfer (CT) pathways in organic semiconductors are important for solar energy applications. To be useful, a photogenerated, Coulombically bound CT exciton must further separate into free charge carriers; direct observations of the detailed CT relaxation pathways, however, are lacking. Here, photoinduced CT and relaxation dynamics in three host-guest complexes, where a perylene (Per) electron donor guest is incorporated into two symmetric and one asymmetric extended viologen cyclophane acceptor hosts, are presented. The central ring in the extended viologen is either p-phenylene (ExV2+) or electron-rich 2,5-dimethoxy-p-phenylene (ExMeOV2+), resulting in two symmetric cyclophanes with unsubstituted or methoxy-substituted central rings, ExBox4+ and ExMeOBox4+, respectively, and an asymmetric cyclophane with one of the central viologen rings being methoxylated ExMeOVBox4+. Upon photoexcitation, the asymmetric host-guest ExMeOVBox4+ ⊃ Per complex exhibits directional CT toward the energetically unfavorable methoxylated side due to structural restrictions that facilitate strong interactions between the Per donor and the ExMeOV2+ side. The CT state relaxation pathways are probed using ultrafast optical spectroscopy by focusing on coherent vibronic wavepackets, which are used to identify CT relaxations along charge localization and vibronic decoherence coordinates. Specific low- and high-frequency nuclear motions are direct indicators of a delocalized CT state and the degree of CT character. Our results show that the CT pathway can be controlled by subtle chemical modifications of the acceptor host in addition to illustrating how coherent vibronic wavepackets can be used to probe the nature and time evolution of the CT states.

Identification of Chemical and Structural Characteristics of Acrylic Paint Layer Using Terahertz Metasurfaces.

The precise investigation and monitoring of the internal structural change within complex layered systems are crucial, as the emergence of undesirable defects or formation of secondary internal structures significantly exerts a profound influence on the overall properties of the system. We demonstrate an advanced sensing platform utilizing terahertz metasurfaces, allowing chemical detection and precise identification within an acrylic paint layer with a noticeable sensitivity, reaching down to several hundreds of nanometers, in nondestructive and noncontact manners. The identification of solid and mixed paint samples was achieved by analyzing their optical properties, including the refractive index and absorption coefficient. Notably, the presence of internal pore defects within the mixed acrylic paint led to geometric distortions, affecting the state of the overall system. Intriguingly, even in cases where acrylic paint exhibited identical colors perceptible under visible light, distinct discrimination and identification of chemical compositions were successfully proposed.

Two-Dimensional Electronic Spectroscopy Reveals Vibrational Modes Coupled to Charge Transfer in a Julolidine-BODIPY Dyad.

Understanding charge transfer (CT) dynamics in molecular donor-acceptor (D-A) dyads can provide insight into developing efficient D-A molecules for capturing solar energy. Here, we characterize the excited-state evolution of a julolidine-BODIPY (Jul-BD) D-A system with an emissive CT state using time-resolved fluorescence, femtosecond transient absorption, and two-dimensional electronic spectroscopies. Comparison of these results with those from phenyl-BODIPY (Ph-BD) allows us to identify the dynamics at play during CT state formation and its subsequent conversion to either a fully charge-separated or triplet state. Photoexcitation of Jul-BD in tetrahydrofuran results in the formation of an initial emissive CT state that relaxes before fully charge-separating. In contrast, Jul-BD in toluene exhibits similar CT state dynamics, albeit at slower timescales, before decaying to a terminal triplet species. Quantum beat analysis at early times in both solvents shows several vibronic modes, which are corroborated using density functional theory (DFT) calculations. For Ph-BD, a single 220 cm-1 compression mode about the single bond linking the phenyl to BODIPY modulates their orbital overlap. Three active vibronic modes, 147, 174, and 214 cm-1, are found in Jul-BD, regardless of the dielectric constant of the medium. These motions correspond to compression and torsional motions along the single bond joining Jul to BD and are responsible for the evolution of the spontaneous and stimulated emission features in the time-resolved spectroscopic data, which is further supported by time-dependent DFT calculations of the steady-state absorption spectrum of the Jul-BD as a function of increasing D-A dihedral core angle. These findings show how torsional and compression motions can play a pivotal role in intramolecular CT between a D and an A linked by a single bond.

Dispersion of droplets due to the use of air purifiers during summer: Focus on the spread of COVID-19.

Coronavirus disease (COVID-19), which emerged in 2019, has induced worldwide chaos. The main cause of COVID-19 mass infection indoors is the spread of virus-containing droplets via indoor airflow, which is affected by air conditioners and purifiers. Here, ten experimental cases were established to analyze how use of air purifiers affects the spread of virus-containing droplets. The experiments were conducted in a school classroom with an air conditioner in summer. In the droplet dispersion experiment, paraffin oil was used as the droplet substance. Two main scenarios were simulated: (1) an infected student was seated in the back of the classroom; and (2) the teacher, standing in the front of the classroom, was infected. The results were expressed using two parameters: peak concentration and loss rate, which reflect the degree of direct and indirect infection (airborne infection), respectively. The air purifier induced a peak concentration decrease of 42% or an increase of 278%, depending on its location in the classroom. Conversely, when the air purifier was operated in the high mode (flow rate = 500 CMH; cubic meters per hour), the loss rate showed that the amount of droplet nuclei only decreased by 39% and the droplet amount decreased by 22%. Thus, the airborne infection degree can be significantly reduced. Finally, the use of air purifiers in the summer may be helpful in preventing group infections by reducing the loss rate and peak concentration if the air purifier is placed in a strategic location, according to the airflow of the corresponding room.

Teaching with collective resilience during COVID-19: Korean teachers and collaborative professionalism.

This study applies system-focused resilience and collaborative professionalism to examine how teachers in Korea collectively developed resilience and transformed teaching during COVID-19. Using qualitative data from seven individual interviews and four focus groups, we found Korean teachers navigated complex challenges (rapidly changing policies, online teaching, exacerbated learning gaps, and excessive social pressure) and utilized contextual resources (collective autonomy and flexibility, solidity and solidarity, and collective responsibility) to develop strategies (collaborative inquiry, timely communication, and envisioning the future of schooling). The study extends teacher resilience toward more collective and communal, from the individual level, by linking resilience to collaborative systemic changes.

π-Stacking-Dependent Vibronic Couplings Drive Excited-State Dynamics in Perylenediimide Assemblies.

Vibronic coupling, the interplay of electronic and nuclear vibrational motion, is considered a critical mechanism in photoinduced reactions such as energy transfer, charge transfer, and singlet fission. However, our understanding of how particular vibronic couplings impact excited-state dynamics is lacking due to the limited number of experimental studies of model molecular systems. Herein, we use two-dimensional electronic spectroscopy (2DES) to launch and interrogate a range of vibronic coherences in two distinct types of perylenediimide slip stacks─along the short and long molecular axes, which form either an excimer or a mixed state between the Frenkel exciton (FE) and charge transfer states. We explore the functionality of these vibronic coherences using quantum beatmaps, which display the Fourier amplitude signal oscillations as a function of pump and probe frequencies, along with knowledge of the characteristic signatures of the FE, ionic, and excimer species. We find that a low-frequency vibrational mode of the short-axis slip stack appears concomitantly with the formation of the excimer state, survives 2-fold longer than in the FE state in the reference monomer, and shows a phase shift compared to other modes. For the long-axis slip stacks, a pair of low-frequency modes coupled to a high-frequency coordinate of the FE state were found to play a critical role in mixed-state generation. Our findings thus experimentally reveal the complex and varying roles of vibronic couplings in tightly packed multimers undergoing a range of photoinduced processes.

Transformation of Supramolecular Membranes to Vesicles Driven by Spontaneous Gradual Deprotonation on Membrane Surfaces.

The various proteins and asymmetric lipid bilayers present in cell membranes form curvatures, resulting in structural transformations to generate vesicles. Fission and fusion processes between vesicles and cell membranes are reversible in living organisms. Although the transformation of a two-dimensional membrane to a three-dimensional vesicle structure is a common natural phenomenon, the lack of a detailed understanding at the molecular level limits the development of synthetic systems for functional materials. Herein, we report a supramolecular membrane system through donor-acceptor interactions using a π-deficient acceptor and π-rich donor as building blocks. The reduced electrostatic repulsion between ammonium cations and the spontaneously deprotonated neutral amino group induced anisotropic membrane curvature, resulting in membrane fission to form vesicles with a detailed understanding at the molecular level. Furthermore, the reversible transformation of vesicles to membranes upon changing the pH provides a novel synthetic system exhibiting both fission and fusion processes.

Binding mode of brazzein to the taste receptor based on crystal structure and docking simulation.

Several natural substances including protein produce sweet taste. Brazzein, derived from the plant Pentadipladra brazzeana, is one of the sweet proteins that bind to the taste receptor with stronger sweetness than sugar. Mutations of this protein affect its flavour, yielding higher sweetness in D29K and lower sweetness in R43A. To elucidate its sweet mechanism in the taste receptor, we determined the structures of two variants, D29K and R43A, to a resolution of 1.5 Å and 1.3 Å, respectively. Structures of the brazzein exhibit two α-helix and three ß-sheets connected by four disulfide bonds with a significantly altered electrostatic distribution on the surface. Using the high-resolution structure data and models of the taste receptors T1R2 and T1R3 in the AlphaFold Protein Structure Database, we performed a docking calculation on the receptors and report that brazzein is bound between the two cysteine rich domains (CRDs) of the heterodimer protein complex. Substitution to lysine in D29K resulted in an increased number of hydrogen bonds in the T1R2 receptor, while substitution to alanine in R43A ablated a polar interaction in the T1R3 receptor. The significantly altered interaction of the variants at the interface is consistent with a change of the sweetness. The high-resolution structure and the docking model in this study may provide a structural basis to understand the flavour mechanism induced by the sweet protein.

Juggling with fluorescent proteins: Spectrum and structural changes of the mCardinal2 variants.

mCardinal2 is a red fluorescent protein developed through the designs of mKate, mNeptune and mCardinal. Fluorescence spectrums of mCardinal2 and its five mutants (T143C, T143G, C158A, C158D and M160E) were measured with their quantum yields. C158A and C158D increased brightness with slight changes in fluorescence spectrums while T143C, T143G and M160E decreased brightness with blue shift in fluorescence spectrums, which resulted in green, cyan and green fluorescent proteins respectively. Crystal structures of all six variants were analyzed and compared together with those of mKate, LSS-mKate1, LSS-mKate2 and mCardinal. Around the Cα-Cß bond of Tyr64 in the MYG chromophores, only C158A and C158D were in the trans conformation while all others were mostly in the cis conformation. Blue-shift brightness-decreased variants (T143C, T143G and M160E) showed the diminished hydrogen bonds while large-Stoke-shift brightness-increased variant C158D showed the enhanced hydrogen bonds around the chromophore.

Analysis of semi-volatile organic compounds in indoor dust and organic thin films by house type in South Korea.

In this study, semi-volatile organic compounds (SVOCs) in samples of indoor dust and organic thin films obtained from 100 residential houses in South Korea, were examined, based on both target analysis using gas chromatography-mass spectrometry (GC-MS) and non-target analysis by gas chromatography-quadrupole time-of flight mass spectrometry (GC-QTOF-MS) screening. In the targeted approach, phthalates and polycyclic aromatic hydrocarbons (PAHs) were analyzed in dust and organic film samples, to find that both these classes of SVOCs were detected in dust and organic film samples, with the median concentrations of eight phthalates (Σ8 phthalate) and 16 PAHs (Σ16 PAH) being 1015.93 µg/g and 1824.97 ng/g in the dust samples, and 75.79 µg/m2 and 2252.78 ng/m2 in the organic film samples, respectively. Among the phthalates, in all house types. bis(2-ethylhexyl) phthalate (DEHP) was detected at the highest concentration, followed by dibutyl phthalate (DBP) and diisobuthyl phthalate (DiBP), with DEHP levels found to be highest in dwelling houses. DEHP levels were found to be significantly associated with building age and renovation status. Lower levels of DEHP were detected in houses less than 10 years old or that had undergone renovation in the previous 10 years. Among the assessed PAHs, a significant correlation was detected between benzo(a)pyrene in dust and building age (p < 0.05). These findings imply that the inhabitants of older houses are at a greater risk of exposure to SVOCs originating from indoor dust and organic films. Non-target screening of selected dust and organic film samples using GC-QTOF-MS data revealed the presence of numerous SVOC compounds, including triphenylphosphine oxide, (Z)-9-octadecenamide, and cyclosiloxanes, along with certain organophosphate flame retardants including tris(1-chloro-2-propyl) phosphate (TCPP) and tris(1,3-dichloroisopropyl) phosphate (TDCPP), and plasticizers. These compounds identified in the non-target screening are of emerging concern, and their presence in dust and organic films needs to be estimated.

Association between gastric cancer and the risk of depression among South Korean adults.

OBJECTIVES: The diagnosis and treatment of cancer are stressful events that could trigger psychological distress in a large number of cancer patients. The aim of this study was to examine the association between gastric cancer and the risk of new onset of depression among South Korean adults. METHODS: Data from 12,664 participants aged over 40 years was derived from the National Health Service National Sample Cohort (2002-2013). The case cohort consists of patients who received a diagnosis of gastric cancer between 2002 and 2009, and the corresponding control group was selected through 1:1 propensity score matching (case: 6332, control: 6332). The new onset of depression was considered as the dependent variable. A Cox proportional hazards regression model was built to analyze the associations between variables in consideration. RESULTS: Individuals with gastric cancer had a higher risk of new onset of depression than those without cancer (hazard ratio [HR] = 1.28, 95% confidence interval [CI] = 1.13-1.45.) Female gastric patients had a higher risk of depression compared to male patients (Female; HR = 1.89, 95% CI = 1.66-2.16, Male; HR = 1.25, 95% CI = 1.10-1.41). Gastric cancer patients in their 60s had the highest risk of new onset of depression compared to other age groups and no cancer group (HR = 1.61, 95% CI = 1.40-1.85). Gastric cancer patients who were previously diagnosed with depression prior to their diagnosis of cancer had a higher risk of new onset of depression than gastric cancer patients without antecedent diagnosis of depression (Past Depression (Yes); HR = 5.17, 95% CI = 4.10-6.51, Past Depression (No); HR = 1.35, CI = 1.21-1.51). CONCLUSIONS: The study identified a significant relationship between gastric cancer and depression among South Korean adults, suggesting that the diagnosis and treatment of gastric cancer increases the risk of new onset of depression, especially among female patients between 60 and 69 years old of high income and living in metropolitan regions. Pre-existing health conditions also appeared to be a risk factor. Thus, in consideration of treatment efficacy and patients' quality of life, the results of the study emphasizes the need for attentive intervention, while distinguishing the most vulnerable groups.

Resolution-enhanced optical inspection system to examine metallic nanostructures using structured illumination.

We developed a structured illumination-based optical inspection system to inspect metallic nanostructures in real time. To address this, we used post-image-processing techniques to enhance the image resolution. To examine the fabricated metallic nanostructures in real time, a compact and highly resolved optical inspection system was designed for practical industrial use. Structured illumination microscopy yields multiple images with various linear illumination patterns, which can be used to reconstruct resolution-enhanced images. Images of nanosized posts and complex structures reflected in the structured illumination were reconstructed into images with improved resolution. A comparison with wide-field images demonstrates that the optical inspection system exhibits high performance and is available as a real-time nanostructure inspection platform. Because it does not require special environmental conditions and enables multiple systems to be covered in arrays, the developed system is expected to provide real-time and noninvasive inspections during the production of large-area nanostructured components.

Phenethyl Isothiocyanate-Conjugated Chitosan Oligosaccharide Nanophotosensitizers for Photodynamic Treatment of Human Cancer Cells.

The aim of this study is to synthesize phenethyl-conjugated chitosan oligosaccharide (COS) (abbreviated as ChitoPEITC) conjugates and then fabricate chlorin E6 (Ce6)-incorporated nanophotosensitizers for photodynamic therapy (PDT) of HCT-116 colon carcinoma cells. PEITC was conjugated with the amine group of COS. Ce6-incorporated nanophotosensitizers using ChitoPEITC (ChitoPEITC nanophotosensitizers) were fabricated by dialysis method. 1H nuclear magnetic resonance (NMR) spectra showed that specific peaks of COS and PEITC were observed at ChitoPEITC conjugates. Transmission electron microscope (TEM) confirmed that ChitoPEITC nanophotosensitizers have spherical shapes with small hydrodynamic diameters less than 200 nm. The higher PEITC contents in the ChitoPEITC copolymer resulted in a slower release rate of Ce6 from nanophotosensitizers. Furthermore, the higher Ce6 contents resulted in a slower release rate of Ce6. In cell culture study, ChitoPEITC nanophotosensitizers showed low toxicity against normal CCD986Sk human skin fibroblast cells and HCT-116 human colon carcinoma cells in the absence of light irradiation. ChitoPEITC nanophotosensitizers showed a significantly higher Ce6 uptake ratio than that of free Ce6. Under light irradiation, cellular reactive oxygen species (ROS) production of nanophotosensitizers was significantly higher than that of free Ce6. Especially, PEITC and/or ChitoPEITC themselves contributed to the production of cellular ROS regardless of light irradiation. ChitoPEITC nanophotosensitizers showed significantly higher PDT efficacy against HCT-116 cells than that of free Ce6. These results indicate that ChitoPEITC nanophotosensitizers have superior potential in Ce6 uptake, ROS production and PDT efficacy. In the HCT-116 cell-bearing mice tumor-xenograft model, ChitoPEITC nanophotosensitizers efficiently inhibited growth of tumor volume rather than free Ce6. In the animal imaging study, ChitoPEITC nanophotosensitizers were concentrated in the tumor tissue, i.e., fluorescence intensity in the tumor tissue was stronger than that of other tissues. We suggest that ChitoPEITC nanophotosensitizers are a promising candidate for the treatment of human colon cancer cells.

Effects and Mechanism of Particulate Matter on Tendon Healing Based on Integrated Analysis of DNA Methylation and RNA Sequencing Data in a Rat Model.

Exposure to particulate matter (PM) has been linked with the severity of various diseases. To date, there is no study on the relationship between PM exposure and tendon healing. Open Achilles tenotomy of 20 rats was performed. The animals were divided into two groups according to exposure to PM: a PM group and a non-PM group. After 6 weeks of PM exposure, the harvest and investigations of lungs, blood samples, and Achilles tendons were performed. Compared to the non-PM group, the white blood cell count and tumor necrosis factor-alpha expression in the PM group were significantly higher. The Achilles tendons in PM group showed significantly increased inflammatory outcomes. A TEM analysis showed reduced collagen fibrils in the PM group. A biomechanical analysis demonstrated that the load to failure value was lower in the PM group. An upregulation of the gene encoding cyclic AMP response element-binding protein (CREB) was detected in the PM group by an integrated analysis of DNA methylation and RNA sequencing data, as confirmed via a Western blot analysis showing significantly elevated levels of phosphorylated CREB. In summary, PM exposure caused a deleterious effect on tendon healing. The molecular data indicate that the action mechanism of PM may be associated with upregulated CREB signaling.

Real-time Observation of Structural Dynamics Triggering Excimer Formation in a Perylene Bisimide Folda-dimer by Ultrafast Time-Domain Raman Spectroscopy.

In π-conjugated organic photovoltaic materials, an excimer state has been generally regarded as a trap state which hinders efficient excitation energy transport. But despite wide investigations of the excimer for overcoming the undesirable energy loss, the understanding of the relationship between the structure of the excimer in stacked organic compounds and its properties remains elusive. Here, we present the landscape of structural dynamics from the excimer formation to its relaxation in a co-facially stacked archetypical perylene bisimide folda-dimer using ultrafast time-domain Raman spectroscopy. We directly captured vibrational snapshots illustrating the ultrafast structural evolution triggering the excimer formation along the interchromophore coordinate on the complex excited-state potential surfaces and following evolution into a relaxed excimer state. Not only does this work showcase the ultrafast structural dynamics necessary for the excimer formation and control of excimer characteristics but also provides important criteria for designing the π-conjugated organic molecules.

Charge-Delocalized State and Coherent Vibrational Dynamics in Rigid PBI H-Aggregates.

Herein, the ultrafast photoinduced dynamics and vibrational coherences for two perylenebisimide (PBI) H-aggregates showcase the formation of the excimer state and the delocalized radical anion state in the excited state, respectively. Using femtosecond transient absorption (fs-TA) and time-resolved impulsive stimulated Raman scattering (TR-ISRS) measurements, we unveiled excited-state dynamics of PBI H-aggregates in two aspects: (1) the intermolecular interactions between PBI units in H-aggregates induce the formation of new excited states, excimer and delocalized radical anion states, and (2) the intermolecular out-of-plane along the aggregate axis and the PBI core C═C stretch Raman modes can be a crucial indicator to understand the coherent exciton dynamics in H-aggregates. Notably, those excited-state Raman modes showed stationary peak positions during the excited-state dynamics. TR-ISRS analysis provides insights into the excited-state vibrational coherences concerning the formation of the excimer and charge-delocalized state in each aggregate system.