Computational models for coupled electronic-vibrational energy transfer in biological photosynthetic complexes

The specialized pigment-protein complexes involved in the first process of photosynthesis are light-harvesting structures that are composed of networks of chromophores in protein scaffolds. Though light-harvesting complexes vary in chromophore composition and protein structure, they are capable of transferring the absorbed energy as molecular excitation energy from chromophore to chromophore with maximal efficiency. Thus, numerous interdisciplinary studies focus on elucidating energy transfer mechanisms in these biological complexes and how the same principles can be applied to artificial photosynthetic and photovoltaic machines. From advanced spectroscopic measurements and theoretical models, the interaction between the excited electronic states and the nuclear vibrational degrees of freedom is now established to be crucial for efficient energy transfer. In light-harvesting complexes of plants and bacteria, it is now understood that the classical-like vibrational modes of the protein and solvent environment drive energy transfer between the energetically close electronic states of the chromophores. On the other hand, recent spectroscopic measurements on algae light-harvesting complexes discovered signatures of quantized, high frequency vibrational modes of the chromophore. Unfortunately, a deterministic interpretation of the data and the underlying Hamiltonian is hindered due to significant inhomogeneous spectral line-broadening. Though numerous model Hamiltonians have been proposed from theoretical work, various computational approximations employed in these studies necessitate empirical parameter tuning in order to obtain agreement with benchmark linear optical spectra. Thus in this work, we present a simple, but improved, computational prescription to compute the ensemble of Hamiltonians for four closely-related algae light-harvesting complexes. We verify the reliability of our proposed models by comparing simulated optical spectra with experimental measurements. We show that static disorder and inhomogeneous broadening are significant for phycobiliproteins due to large site energy fluctuations. We also show that the nuclear environment plays an important role in defining the trapping state, or the final energy acceptor. Finally, our work for the first time suggests that EET dynamics can be tuned by varying the titration states of the chromophores

Work-Related Perceptions, Injuries, and Musculoskeletal Symptoms: Comparison Between U.S.-Educated and Foreign-Educated Nurses.

Immigrants account for a significant proportion of the nursing workforce in the United States (U.S.). Although different cultural backgrounds may affect immigrant nurses' perceptions of work and occupational health risks, little research has been conducted. Defining immigrant nurses as those who received initial nursing education in foreign countries, this study examined the differences in work-related perceptions and experiences of musculoskeletal (MS) symptoms and injuries between U.S.-educated and foreign-educated nurses. We analyzed data from a cross-sectional study using a statewide random sample of 419 California registered nurses. Foreign-educated nurses reported a more positive safety climate (p = .017) and perceived their jobs as less demanding (p = .008) than did U.S.-educated nurses. The prevalence of work-related MS symptoms was significantly lower in foreign-educated nurses than in U.S.-educated nurses (p = .044), but the difference was not significant in the multivariable analyses. Positive safety climate was significantly associated with a decreased risk of work-related MS symptoms and injuries, and this relationship was greater among U.S.-educated nurses than among foreign-educated nurses. Our findings suggest that immigrant nurses may have different perceptions about safety climate and job demand, which may modify their occupational health risks

Toward Nation Branding Systems: Evidence from Brand Korea Development

This paper offers an integrated view of nation branding on the competitiveness of the country. Nation branding research has evolved through multidimensional contexts, lying on a continuum with the local at the one end and the global at the other. Despite ample evidence showing the great necessity of conceptual clarity of nation branding, there has been little challenge to theoretical convergence of nation branding. Particularly emphasizing the brand Korea development from the 1960s to the 1990s, our paper corroborates the conceptual evidence of nation branding and provides an understanding about the legitimate role of nation branding to international and area studies

Aptamers and Their Biological Applications

Recently, aptamers have attracted the attention of many scientists, because they not only have all of the advantages of antibodies, but also have unique merits, such as thermal stability, low cost, and unlimited applications. In this review, we present the reasons why aptamers are known as alternatives to antibodies. Furthermore, several types of in vitro selection processes, including nitrocellulose membrane filtration, affinity chromatography, magnetic bead, and capillary electrophoresis-based selection methods, are explained in detail. We also introduce various applications of aptamers for the diagnosis of diseases and detection of small molecules. Numerous analytical techniques, such as electrochemical, colorimetric, optical, and mass-sensitive methods, can be utilized to detect targets, due to convenient modifications and the stability of aptamers. Finally, several medical and analytical applications of aptamers are presented. In summary, aptamers are promising materials for diverse areas, not just as alternatives to antibodies, but as the core components of medical and analytical equipment

Textile Relics Conservation and Effective Cleaning Methods - Conservation of the Korean Youth Baseball Tournament Championship Flag

This study analyzes the effectiveness of the cleaning methods applied to the Korean Youth Baseball Tournament championship flag, Korean cultural asset no. 498, which is currently owned by the Korean Sports Council. This championship flag was first given to the winning baseball team during the Chosun National Athletic Meet in July, 1920 and therefore carries importance in Korean sports history. The conservation process began with the following goals: to understand the current condition of the relic, to reduce the soils, to repair and reinforce the deteriorated areas, and to prevent further major damages to the relic

Histamine and Histamine H4 Receptor Promotes Osteoclastogenesis in Rheumatoid Arthritis.

Histamine H4 receptor (H4R) has immune-modulatory and chemotaxic effects in various immune cells. This study aimed to determine the osteoclastogenic role of H4R in rheumatoid arthritis (RA). The concentration of histamine in synovial fluid (SF) and sera in patients with RA was measured using ELISA. After RA SF and peripheral blood (PB) CD14+ monocytes were treated with histamine, IL-17, IL-21 and IL-22, and a H4R antagonist (JNJ7777120), the gene expression H4R and RANKL was determined by real-time PCR. Osteoclastogenesis was assessed by counting TRAP-positive multinucleated cells in PB CD14+ monocytes cultured with histamine, Th17 cytokines and JNJ7777120. SF and serum concentration of histamine was higher in RA, compared with osteoarthritis and healthy controls. The expression of H4R was increased in PB monocytes in RA patients. Histamine, IL-6, IL-17, IL-21 and IL-22 induced the expression of H4R in monocytes. Histamine, IL-17, and IL-22 stimulated RANKL expression in RA monocytes and JNJ7777120 reduced the RANKL expression. Histamine and Th17 cytokines induced the osteoclast differentiation from monocytes and JNJ7777120 decreased the osteoclastogenesis. H4R mediates RANKL expression and osteoclast differentiation induced by histamine and Th17 cytokines. The blockage of H4R could be a new therapeutic modality for prevention of bone destruction in RA

Multi-cellular natural killer (NK) cell clusters enhance NK cell activation through localizing IL-2 within the cluster

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Nutrients in Infancy

Infants are not just small adults; they have a complex set of nutrient requirements and interactions to account for the high metabolic rate, growth, immunological and cognitive development, etc. Each year there are 138 million births, including 30 million from the least developed countries, where health is most at risk. Nutrition during infancy establishes growth patterns and development which moderate short term and long term health and life expectancy. There is continuing progress in understanding the nutrient composition of breastmilk and the importance nutritious and timely complementary foods. Nutrients at particular risk in the first years of life are iron, iodine, and vitamins A and D. There are still gaps in our knowledge on the influence of maternal diet, body composition and nutritional status on breastmilk nutrients. Interaction of nutrients with the human microbiome and gastro-intestinal tract hormonal secretion are developing fields. While breastmilk remains the “gold standard of pediatric nutrition”, the provisions of nutrients providing for optimal health in infant formulae, including nutrients and probiotics remains an area of research. The assessment of body composition for research and clinical practice has progressed rapidly and is important in understanding later obesity. After six months of age, there are new issues of the interaction of weaning foods and later family foods with the maturing gastro-intestinal tract to promote health and growth. Infant nutrition is made more difficult (and interesting) by the many cultural beliefs related to feeding practices. Developments in all of these fields of research into pediatric nutrition will be explored in this special issue together with state of the art reviews