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Exploring structural biomimicry is a great opportunity to replicate hierarchical frameworks inspired by nature in advanced functional materials for boosting new applications. In this work, we present the biomimetic integration of polythiophene into chitosan nanofibrils in a twisted Bouligand structure to afford free-standing macroscopic composite membranes with electrochemical functionality. By considering the integrity of the Bouligand structure in crab shells, we can produce large, free-standing chitosan nanofibril membranes with iridescent colors and flexible toughness. These unique structured features lead the chitosan membranes to host functional additives to mimic hierarchically layered composites. We used the iridescent chitosan nanofibrils as a photonic platform to investigate the host-guest combination between thiophene and chitosan through oxidative polymerization to fabricate homogeneous polythiophene-wrapped chitosan composites. This biomimetic incorporation fully retains the twisted Bouligand organization of nanofibrils in the polymerized assemblies, thus giving rise to free-standing macroscopic electrochemical membranes. Our further experiments are the modification of the biomimetic polythiophene-wrapped chitosan composites on a glassy carbon electrode to design a three-electrode system for simultaneous electrochemical detection of uric acid, xanthine, hypoxanthine, and caffeine at trace concentrations.

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This study focused on the chemical composition and biological activities of the essential oil derived from Grewia bulot, a plant species known for its medicinal properties. The analysis of Grewia bulot essential oil revealed the presence of 78 constituents. The major compounds were α-cadinol (13.5%), 1,8-cineole (12.7%), 1,10-di-epi-cubenol (9.8%), epi-α-cadinol (6.7%), (E,E)-α-farnesene (5.9%), (E)-citral (4.0%), selin-11-en-4-α-ol (4.0%), citronellol isobutanoate (3.9%), and geranic acid (3.7%). The essential oil exhibited promising antioxidant potential with an IC50 value of 452.65 ± 28.40 µg/mL in DPPH model. This oil did not show NO production inhibitory effect in RAW 264.7 cells. In addition, the essential oil exhibited significant cytotoxicity against KB, Hep-G2, MCF-7, and SK-LU-1 cancer cell lines, with IC50 values ranging from 44.04 ± 1.47 to 74.20 ± 3.71 µg/mL.

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Purpose: Falls have significant financial impact. Proton pump inhibitor (PPI) therapy is associated with an increased risk of falls and fractures. Exercise programs have been shown to decrease risk of falls in the elderly population and are recommended by the U.S. Preventive Services Task Force for patients over age 65 to reduce falls. Our study aimed to explore the potential financial benefit of implementing three different Centers for Disease Control and Prevention-recommended exercise-based interventions for fall prevention (Tai Chi, Stepping On, and Otago Exercise Program) in ≥65-year-old patients on PPI therapy. Methods: A Markov model was developed to predict the financial implications of fall-related outcomes in the study population. Net cost of the intervention was deducted from the financial savings predicted for fall avoidance relative to the fall reduction conferred by the intervention. Sensitivity analysis was performed on a range of odds ratios between falling and PPI use. Results: Exercise-based interventions were found to offer financial savings when fall reduction rates exceeded 5%, irrespective of variable odds ratios between PPI use and fall rate. Hypothetical implementation of an exercise-based intervention for PPI users ≥65 years of age was estimated to result in annual fall- and fracture-related savings ranging from $10,317.35 to $18,766.28 per individual. Findings suggested an estimated annual reduction in U.S. health care costs of $18 billion to $85 billion. Conclusions: Implementing an exercise-based fall prevention program for elderly PPI users represents a possible strategy to mitigate health care costs in the United States. Future prospective studies are recommended.

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Neuroticism and premenstrual conditions share pleiotropic loci and are strongly associated. It is presently not known which DSM-5 symptoms of premenstrual syndrome/premenstrual mood disorder are associated with neuroticism. We enrolled 45 study participants to provide prospective daily ratings of affective ("depression", "anxiety, "anger", "mood swings") and psychological ("low interest", "feeling overwhelmed", and "difficulty concentrating") symptoms across two-three menstrual cycles (128 total cycles). Generalized additive modeling (gam function in R) was implemented to model the relationships between neuroticism and the premenstrual increase in symptomatology. Significance level was adjusted using the False Discovery Rate method and models were adjusted for current age and age of menarche. Results of the association analysis revealed that "low interest" (p ≤ 0.05) and "difficulty concentrating" (p ≤ 0.001) were significantly associated with neuroticism. None of the remaining symptoms reached statistical significance. The late luteal phase of the menstrual cycle is characterized by complex symptomatology, reflecting a physiological milieu of numerous biological processes. By identifying co-expression between neuroticism and specific premenstrual symptomatology, the present study improves our understanding of the premenstrual conditions and provides a platform for individualized treatment developments.

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The regulation of DHEA-sulfate by steroid sulfotransferase (SULT) and steryl-sulfatase (STS) enzymes is a vital process for the downstream formation of many steroid hormones. DHEA-sulfate is the most abundant steroid hormone in the human body; thus, DHEA-sulfate and its hydrolyzed form, DHEA, continue to be evaluated in numerous studies, given their importance to human health. Yet, a basic question of relevance to the reproductive-age female population-whether the two steroid hormones vary across the menstrual cycle-has not been addressed. We applied a validated, multi-step protocol, involving realignment and imputation of study data to early follicular, mid-late follicular, periovulatory, and early, mid-, and late luteal subphases of the menstrual cycle, and analyzed DHEA-sulfate and DHEA serum concentrations using ultraperformance liquid chromatography tandem mass spectrometry. DHEA-sulfate levels started to decrease in the early luteal, significantly dropped in the mid-luteal, and returned to basal levels by the late luteal subphase. DHEA, however, did not vary across the menstrual cycle. The present study deep-mapped trajectories of DHEA and DHEA-sulfate across the entire menstrual cycle, demonstrating a significant decrease in DHEA-sulfate in the mid-luteal subphase. These findings are relevant to the active area of research examining associations between DHEA-sulfate levels and various disease states.

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OBJECTIVE: Sleep and eating behaviors are disturbed during the premenstrual phase of the menstrual cycle in a significant number of reproductive-age women. Despite their impact on the development and control of chronic health conditions, these behaviors are poorly understood. In the present study, we sought to identify affective and psychological factors which associate with premenstrual changes in sleeping and eating behaviors and assess how they impact functionality. METHODS: Fifty-seven women provided daily ratings of premenstrual symptomatology and functionality across two-three menstrual cycles (156 cycles total). For each participant and symptom, we subtracted the mean day +5 to +10 ("post-menstruum") ratings from mean day -6 to -1 ("pre-menstruum") ratings and divided this value by participant- and symptom-specific variance. We completed the statistical analysis using multivariate linear regression. RESULTS: Low interest was associated with a premenstrual increase in insomnia (p ≤ 0.05) and appetite/eating (p ≤ 0.05). Furthermore, insomnia was associated with occupational (p ≤ 0.001), recreational (p ≤ 0.001), and relational (p ≤ 0.01) impairment. CONCLUSIONS: Results of the present analysis highlight the importance of apathy (i.e., low interest) on the expression of behavioral symptomatology, as well as premenstrual insomnia on impairment. These findings can inform treatment approaches, thereby improving care for patients suffering from premenstrual symptomatology linked to chronic disease conditions.

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Visceral adiposity is a significant marker of all-cause mortality. Reproductive age women are at a considerable risk for developing visceral adiposity; however, the associated factors are poorly understood. The proposed study evaluated whether food craving experienced during the premenstrual period is associated with waist circumference. Forty-six women (mean BMI = 24.36) prospectively provided daily ratings of food craving across two-three menstrual cycles (122 cycles total). Their premenstrual rating of food craving was contrasted against food craving in the follicular phase to derive a corrected summary score of the premenstrual food craving increase. Study groups were divided into normal (n = 26) and obese (n = 20) based on the 80 cm waist circumference cutoff signifying an increase in risk. Waist circumference category was significantly associated with premenstrual food cravings [F (1,44) = 5.12, p = 0.028]. Post hoc comparisons using the Tukey HSD test (95% family-wise confidence level) showed that the mean score for the food craving effect size was 0.35 higher for the abdominally obese vs. normal study groups (95% CI: 0.039 to 0.67). The result was statistically significant even following inclusion of BMI in the model, pointing to a particularly dangerous process of central fat accumulation. The present study establishes an association between temporal vulnerability to an increased food-related behavior and a marker of metabolic abnormality risk (i.e., waist circumference), thereby forming a basis for integrating the premenstruum as a viable intervention target for this at-risk sex and age group.

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INTRODUCTION: Healthcare workers experience a significant risk of exposure to and infection from SARS-CoV-2, COVID-19. Nonetheless, little research has focused on physicians' use of personal protective equipment (PPE), their concerns about becoming infected and their social distancing maneuvers. METHODS: All staff physicians at Advocate Lutheran General Hospital were invited to participate. Their COVID-19 IgG antibody level was measured and an online questionnaire was completed. The questionnaire assessed the risk of COVID-19 exposure, PPE usage, concern for contracting COVID-19, the performance of high-risk procedures, work in high-risk settings, and social distancing practices. Testing was performed in September (T0), and December 2020 (T1) at the height of the global pandemic. RESULTS: A total of 481 (26.7%) of 1800 AGLH physicians were enrolled at T0 and 458 (95% of the original group) at T1. A total of 21 (4.3%) and 39 (8.5%) participants had antibodies at T0 and T1. A total of 63 (13.8%) worked in high-risk settings and 111 (24.2%) performed high-risk procedures. Participants working in high-risk settings had increased exposure to COVID-19 infected patients (OR = 4.464 CI = 2.522-8.459, p < 0.001). Participants were highly adherent to the use of PPE and social distancing practices including mask-wearing in public (86%, 82.1%), avoiding crowds (85.1%, 85.6%), six feet distancing (83.8%, 83.4%), and avoiding public transportation (78%, 83.8%). A total of 251 (55.4%) participants expressed moderate to extreme concern about becoming infected with COVID-19. CONCLUSIONS AND RELEVANCE: Among a group of community physicians, consistent PPE use and social distancing practices were common. These practices were associated with a low level of initial acquisition of COVID-19 infections and a relatively low longitudinal risk of infection.

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Background: Although numerous motivations for vaping have been identified in adolescents, no study to date has examined a possible link between vaping and attitudes/behaviors that are associated with eating disorders in adolescent females. Examining this question in adolescent females is especially relevant given the higher prevalence of eating disorders in adolescent girls and women compared to adolescent boys and men. Methods: We recruited 299 girls (between 13 to 17 years old) via Facebook advertisement to complete a REDCap survey, which included the Electronic Cigarette Dependence Index (ECDI), Minnesota Eating Behavior Survey (MEBS), and demographic questions. Data were analyzed using nonparametric Spearman rank correlation test in R. Results: Electronic Cigarette Dependence Index (ECDI) scores were correlated with weight preoccupation (WP), binge eating (BE) and compensatory behavior (CB), but not body dissatisfaction (BD). The following were the results of Spearman correlation tests: (1) WP: rho = 0.13, p = 0.02; (2) BD: rho = 0.06, p = 0.28; (3) BE: rho = 0.15, p = 0.0095; (4) CB: rho = 0.021, p = 0.00027. Conclusion: The present study adds to the current literature examining motivations for e-cigarette use in adolescent girls. As eating disorders and e-cigarette dependence are significant public health concerns, our results highlight the need for intervention development.

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Simultaneous integration of photon emission and biocompatibility into nanoparticles is an interesting strategy to develop applications of advanced optical materials. In this work, we present the synthesis of biocompatible optical nanocomposites from the combination of near-infrared luminescent lanthanide nanoparticles and water-soluble chitosan. NaYF4:Yb,Er upconverting nanocrystal guests and water-soluble chitosan hosts are prepared and integrated together into biofunctional optical composites. The control of aqueous dissolution, gelation, assembly, and drying of NaYF4:Yb,Er nanocolloids and chitosan liquids allowed us to design novel optical structures of spongelike aerogels and beadlike microspheres. Well-defined shape and near-infrared response lead upconverting nanocrystals to serve as photon converters to couple with plasmonic gold (Au) nanoparticles. Biocompatible chitosan-stabilized Au/NaYF4:Yb,Er nanocomposites are prepared to show their potential use in biomedicine as we find them exhibiting a half-maximal effective concentration (EC50) of 0.58 mg mL-1 for chitosan-stabilized Au/NaYF4:Yb,Er nanorods versus 0.24 mg mL-1 for chitosan-stabilized NaYF4:Yb,Er after 24 h. As a result of their low cytotoxicity and upconverting response, these novel materials hold promise to be interesting for biomedicine, analytical sensing, and other applications.

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In this work, the dependence of the morphology and stability of the extended solid of carbon monoxide (CO) is correlated to the rate of transformation from the molecular CO to extended solid of CO using optical imaging, photoluminescence, Raman spectroscopy, and X-ray diffraction. The analyses show the rate and pressure of the transformation to be strongly controlled by catalytic effects, both chemical and optical. In a larger volume per reaction area, the transformation was found to require either a longer time at an elevated pressure or a higher pressure compared to a sample synthesized in a smaller volume per reaction area, leading to the conclusion that the transformation rate is slower for a sample in a larger volume per reaction area. A faster rate of transformation was also noted when the reaction area of a CO sample was catalyzed with H2SO4. Through variation of the volume per reaction area, pressure or the addition of catalysts, it was possible to control the rate of the phase transition and therefore the morphology. In general, the extended solid of CO synthesized with a faster rate showed a more ordered structure and increased metastability relative to the material formed with a slower compression rate.

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Inspired by nature, collagen is an outstanding polypeptide utilized to exploit its bioactivity and material design for healthcare technologies. In this study, we describe the self-aggregation of water-dispersible nanocollagen helices upon solidification to fabricate different forms of natural collagen materials. Chemically extracted native collagen fibrils are uniform anisotropic nanoparticles with an average diameter of about 50 nm and a high aspect ratio. The as-prepared collagen nanofibrils are soluble in sodium acetate-acetic acid buffer and are dispersible in water, thus generating collagen liquids that are used as distinct biopolymer precursors for materials development. Our interesting findings indicate that water-dispersible collagen-derived alcogels undergo critical point drying to self-arrange hierarchical nanofibrils into helix bundles in collagen sponge-like aerogels. Notably, using lyophilization to remove water in the biopolymer dispersion, a full regeneration of solidified fibers is achieved, producing collagen aerogels with lightweight characteristics similar to natural cottons. The self-aggregation of water-dispersible collagen occurs under freeze-drying conditions to turn individual nanofibrils into sheets with layered structures in the aerogel networks. The development of transparent, water resistant collagen bioplastic-like membranes was achieved by supramolecular self-assembly of water-dispersible collagen nanofibrils. Our efforts present a reliable concept in soft matter for creating promising collagen examples of liquids, hydrogels, aerogels, and membranes to increase utilization value of native collagen for biomedicine, pharmaceuticals, cosmetics, and nutrients.

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Bioinspired materials have aroused great interest as their inherent biocompatible and structural characteristics have given rise to sustainable applications. In this work, we have reported the phase and morphology transformation of chitosan from crystalline nanofibrils into amorphous sheets for fabricating sustainable materials. Acetylation-induced aqueous dissolution of native chitosan nanofibrils affords water-soluble chitosan as a biopolymeric liquid. Water-soluble chitosan macromolecules self-aggregate into amorphous sheets on solidification, presenting an interesting way to inspire new structures of chitosan assemblies. Through control over gelation, lyophilization, and self-assembled confinement of water-soluble chitosan, we have fabricated novel chitosan materials including filaments, aerogels, microspheres, and plastics that are promising for sustainable use.

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Squalene, an intermediate in the biosynthesis of cholesterol, has a 24-carbon backbone with six methyl groups and six isolated double bonds. Capillary flow techniques have been used to determine its translational diffusion constant, D, at room temperature in squalane, n-C16, and three n-C8-squalane mixtures. The D values have a weaker dependence on viscosity, η, than predicted by the Stokes-Einstein relation, D = kBT/(6πηr). A fit to the modified relation, D/T = ASE/η(p), gives p = 0.820 ± 0.028; p = 1 for the Stokes-Einstein limit. The translational motion of squalene appears to be much like that of n-alkane solutes with comparable chain lengths; their D values show similar deviations from the Stokes-Einstein model. The n-alkane with the same carbon chain length as squalene, n-C24, has a near-equal p value of 0.844 ± 0.018 in n-alkane solvents. The values of the hydrodynamic radius, r, for n-C24, squalene, and other n-alkane solutes decrease as the viscosity increases and have a common dependence on the van der Waals volumes of the solute and solvent. The possibility of studying squalene in lipid droplets and membranes is discussed.

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Laser shock Hugoniot data were obtained using ultrafast dynamic ellipsometry (UDE) for both nonideal (ethanol/water solutions with mole percent χ(ethanol) = 0%, 3.4%, 5.4%, 7.5%, 9.7%, 11%, 18%, 33%, 56%, 100%) and ideal liquid mixtures (toluene/fluorobenzene solutions with mole percent χ(toluene) = 0%, 26.0%, 49.1%, 74.9%, 100%). The shock and particle velocities obtained from the UDE data were compared to the universal liquid Hugoniot (ULH) and to literature shock (plate impact) data where available. It was found that the water UDE data fit to a ULH-form equation suggests an intercept of 1.32 km/s, lower than the literature ambient sound speed in water of 1.495 km/s (Mijakovic et al. J. Mol. Liq. 2011, 164, 66-73). Similarly, the ethanol UDE data fit to a ULH-form equation suggests an intercept of 1.45 km/s, which lies above the literature ambient sound speed in ethanol of 1.14 km/s. Both the literature plate impact and UDE Hugoniot data lie below the ULH for water. Likewise, the literature plate impact and UDE Hugoniot data lie above the ULH for ethanol. The UDE Hugoniot data for the mixtures of water and ethanol cross the predictions of the ULH near the same concentration where the sound speed reaches a maximum. In contrast, the UDE data from the ideal liquids and their mixtures are well behaved and agree with ULH predictions across the concentration range. The deviations of the nonideal ethanol/water data from the ULH suggest that complex hydrogen bonding networks in ethanol/water mixtures alter the compressibility of the mixture.

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Using hole-burning spectroscopy, we show that excitation energy transfer (EET) time in ethynyl-linked chlorophyll trefoil (ChlT1) monomer is very fast (∼2.5 ps) at liquid helium temperature. This is consistent with data obtained by femtosecond transient spectroscopy experiments performed at room temperature, in which an EET time of 1.8 ps was observed (Kelley, R. F. et al. Angew. Chem. Int. Ed. 2006, 45, 7979). This finding further supports the importance of through-bond electronic coupling at low temperature. In addition, we show that ChlT1 (even at very low concentrations) in methyl tetrahydrofuran-ethanol glass (1:200 v/v; T ∼ 5 K) forms different types of aggregates. It is demonstrated that the relative distribution of various types of aggregates (whose possible structures are briefly discussed) depends on the cooling rate and matrix composition. For example, the EET time in two types of ChlT1-based aggregates is slower by a factor of ∼5-7 with respect to that observed for ChlT1 monomer. This indicates that ChlT1 aggregates can retain ultrafast energy transfer properties similar to those observed in natural photosynthetic antennas. It is anticipated that such building blocks could be utilized in future photovoltaic devices.

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Plate impact experiments on the (210), (100), and (111) planes were performed to examine the role of crystalline anisotropy on the shock-induced decomposition of cyclotrimethylenetrinitramine (RDX) crystals. Time-resolved emission spectroscopy was used to probe the decomposition of single crystals shocked to peak stresses ranging between 7 and 20 GPa. Emission produced by decomposition intermediates was analyzed in terms of induction time to emission, emission intensity, and the emission spectra shapes as a function of stress and time. Utilizing these features, we found that the shock-induced decomposition of RDX crystals exhibits considerable anisotropy. Crystals shocked on the (210) and (100) planes were more sensitive to decomposition than crystals shocked on the (111) plane. The possible sources of the observed anisotropy are discussed with regard to the inelastic deformation mechanisms of shocked RDX. Our results suggest that, despite the anisotropy observed for shock initiation, decomposition pathways for all three orientations are similar.

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We report low temperature (T) optical spectra of the isolated CP47 antenna complex from Photosystem II (PSII) with a low-T fluorescence emission maximum near 695 nm and not, as previously reported, at 690-693 nm. The latter emission is suggested to result from three distinct bands: a lowest-state emission band near 695 nm (labeled F1) originating from the lowest-energy excitonic state A1 of intact complexes (located near 693 nm and characterized by very weak oscillator strength) as well as emission peaks near 691 nm (FT1) and 685 nm (FT2) originating from subpopulations of partly destabilized complexes. The observation of the F1 emission is in excellent agreement with the 695 nm emission observed in intact PSII cores and thylakoid membranes. We argue that the band near 684 nm previously observed in singlet-minus-triplet spectra originates from a subpopulation of partially destabilized complexes with lowest-energy traps located near 684 nm in absorption (referred to as AT2) giving rise to FT2 emission. It is demonstrated that varying contributions from the F1, FT1, and FT2 emission bands led to different maxima of fluorescence spectra reported in the literature. The fluorescence spectra are consistent with the zero-phonon hole action spectra obtained in absorption mode, the profiles of the nonresonantly burned holes as a function of fluence, as well as the fluorescence line-narrowed spectra obtained for the Q(y) band. The lowest Q(y) state in absorption band (A1) is characterized by an electron-phonon coupling with the Huang-Rhys factor S of approximately 1 and an inhomogeneous width of approximately 180 cm(-1). The mean phonon frequency of the A1 band is 20 cm(-1). In contrast to previous observations, intact isolated CP47 reveals negligible contribution from the triplet-bottleneck hole, i.e., the AT2 trap. It has been shown that Chls in intact CP47 are connected via efficient excitation energy transfer to the A1 trap near 693 nm and that the position of the fluorescence maximum depends on the burn fluence. That is, the 695 nm fluorescence maximum shifts blue with increasing fluence, in agreement with nonresonant hole burned spectra. The above findings provide important constraints and parameters for future excitonic calculations, which in turn should offer new insight into the excitonic structure and composition of low-energy absorption traps.

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It is still unclear whether hyperquenched water (i.e., amorphous glassy water) heated to about 140-150 K remains glassy until it crystallizes near 154 K or whether instead it turns into a supercooled and very viscous liquid. It has been proposed that the glass transition temperature (T(g)) for water is 165 K and not, as previously thought, 136 K [V. Velikov et al., Science, 294, 2335 (2001)]. Support for both interpretations exists in the literature, since the T(g) of water is difficult to measure due to the formation of metastable cubic ice (I(c)) near 154 K. To address the nature of water in the 110-160 K temperature range, a confocal microscopy approach is used to study whether single-probe molecules (i.e., Rhodamine 700, Rh-700) embedded in hyperquenched glassy water (HGW) rotate in the temperature range of 110-160 K. If T(g) is 136 K and the liquid above this temperature is fragile (or strong with the fragility index m > 7), then rotation of the Rh-700 molecules should be observed several degrees above T(g). It is shown that no anticorrelated fluorescence intensity changes of single molecules in HGW (when excited at orthogonal polarizations) were observed up to temperatures of 160 K, although such changes were detected in control experiments performed for hyperquenched glassy ethanol (fragile liquid) at 99 K, that is, at T(g) + 2 K. The viscosity at which single Rh-700 molecules rotate in ethanol at 99 K is estimated to be about 10(12) poise. Since single-molecule spectroscopy did not reveal any rotation of probe molecules in HGW above 136 K, we conclude that water above 136 K is most likely a solid (i.e., glass), supporting the assignment that water remains glassy until it crystallizes near T = 154 K. It cannot be excluded, of course, that the value of m for water is smaller than 7 (i.e., water above 136 K could be an extremely strong liquid), but this possibility is considered unlikely as this would make water the strongest liquid ever known.

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The CP43 core antenna complex of photosystem II is known to possess two quasi-degenerate "red"-trap states (Jankowiak, R. et al. J. Phys. Chem. B 2000, 104, 11805). It has been suggested recently (Zazubovich, V.; Jankowiak, R. J. Lumin. 2007, 127, 245) that the site distribution functions of the red states (A and B) are uncorrelated and that narrow holes are burned in the subpopulations of chlorophylls (Chls) from states A and B that are the lowest-energy Chl in their complex and previously thought not to transfer energy. This model of uncorrelated excitation energy transfer (EET) between the quasidegenerate bands is expanded by taking into account both electron-phonon and vibrational coupling. The model is applied to fit simultaneously absorption, emission, zero-phonon action, and transient hole burned (HB) spectra obtained for the CP43 complex with minimized contribution from aggregation. It is demonstrated that the above listed spectra can be well-fitted using the uncorrelated EET model, providing strong evidence for the existence of efficient energy transfer between the two lowest energy states, A and B (either from A to B or from B to A), in CP43. Possible candidate Chls for the low-energy A and B states are discussed, providing a link between CP43 structure and spectroscopy. Finally, we propose that persistent holes originate from regular NPHB accompanied by the redistribution of oscillator strength due to excitonic interactions, rather than photoconversion involving Chl-protein hydrogen bonding, as suggested before ( Hughes J. L. et al. Biochemistry 2006, 45, 12345 ). In the accompanying paper (Reppert, M.; Zazubovich, V.; Dang, N. C.; Seibert, M.; Jankowiak, R. J. Phys. Chem. B 2008, 9934), it is demonstrated that the model discussed in this manuscript is consistent with excitonic calculations, which also provide very good fits to both transient and persistent HB spectra obtained under non-line-narrowing conditions.

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