Distinguishing the roles of energy funnelling and delocalization in photosynthetic light harvesting

Photosynthetic complexes improve the transfer of excitation energy from peripheral antennas to reaction centers in several ways. In particular, a downward energy funnel can direct excitons in the right direction, while coherent excitonic delocalization can enhance transfer rates through the cooperative phenomenon of supertransfer. However, isolating the role of purely coherent effects is difficult because any change to the delocalization also changes the energy landscape. Here, we show that the relative importance of the two processes can be determined by comparing the natural light-harvesting apparatus with counterfactual models in which the delocalization and the energy landscape are altered. Applied to the example of purple bacteria, our approach shows that although supertransfer does enhance the rates somewhat, the energetic funnelling plays the decisive role. Because delocalization has a minor role (and is sometimes detrimental), it is most likely not adaptive, being a side-effect of the dense chlorophyll packing that evolved to increase light absorption per reaction center

A single-center cross-sectional study on the relationship between mental health, communication skills, and maladaptive schemas with nurses' job motivation

BACKGROUND: Human resources are considered as the most important capital in health care system of the country. This study was conducted to investigate the relationship between mental health, communication skills, and maladaptive schemas with nurses' job motivation.METHODS: In a cross-sectional study, during October 2018 to January 2019, 120 active nurses in Alborz Hospital, Karaj, Iran, were selected by available sampling method. The data were collected using General Health Questionnaire (GHQ), Interpersonal Communication Skills Test, Young's Early Maladaptive Schema Questionnaire (YEMSQ), and Employee Motivation Questionnaire and were analyzed using Pearson correlation and multivariable regression tests in the software environment of SPSS.RESULTS: The results of simultaneous regression showed that the message receiving sequence indices (β = -2.32), emotional control (β = -1.98), listening (β = -1.97), insight into relationship (β = 1.06), relationship with decisiveness (β = -1.45), and communicational skills (β = -7.45) were predictors of job motivation (P < 0.010). Also, the components of failure (β = -0.19) and anxiety/insomnia (β = -0.20) were predictors of job motivation (P < 0.010). There was a significant positive relationship between sacrifice schemas, harsh criteria, and desirability with job motivation (P < 0.050). In addition, there was a significant negative relationship between failure schemas and job motivation (P < 0.050), but other variables were not able to predict job motivation (P < 0.050).CONCLUSION: The findings of this study indicate that there is a relationship between psychological indices and job motivation in nurses. These findings can have clinical applications in the planning of major programs in the field of health and treatment

Odd-even effects in charge transport across n-alkanethiolate-based SAMs

This paper compares rates of charge transport across self-assembled monolayers (SAMs) of n-alkanethiolates having odd and even numbers of carbon atoms (nodd and neven) using junctions with the structure MTS/SAM//Ga2O3/EGaIn (M = Au or Ag). Measurements of current density, J(V), across SAMs of n-alkanethiolates on AuTS and AgTS demonstrated a statistically significant odd-even effect on AuTS, but not on AgTS, that could be detected using this technique. Statistical analysis showed the values of tunneling current density across SAMs of n-alkanethiolates on AuTS with nodd and neven belonging to two separate sets, and while there is a significant difference between the values of injection current density, J0, for these two series (log|J0Au,even| = 4.0 ± 0.3 and log|J0Au,odd| = 4.5 ± 0.3), the values of tunneling decay constant, β, for nodd and neven alkyl chains are indistinguishable (βAu,even = 0.73 ± 0.02 Å-1, and βAu,odd= 0.74 ± 0.02 Å-1). A comparison of electrical characteristics across junctions of n-alkanethiolate SAMs on gold and silver electrodes yields indistinguishable values of β and J0 and indicates that a change that substantially alters the tilt angle of the alkyl chain (and, therefore, the thickness of the SAM) has no influence on the injection current density across SAMs of n-alkanethiolates

Involvement of Central β-Adrenergic Circuitry in Food and Water Intake in Chickens

We examined the effects of intracerebroventricular (i.c.v.) microinjections of α, β-adrenergic agonist, isoproterenol (ISOP), and of a β₁,₂-adrenoceptor blocker, propranolol (PROP), on food and water intake in broiler cockerels deprived of food and water for 3 h. We found that ISOP, at a 200 nM concentration and not smaller, significantly (P ≤ 0.05) increased food intake but not water intake. PROP microinjected in different doses (20-80 mM) significantly (P ≤ 0.05) decreased food intake. These observation suggest a direct orexigenic role for the β₁ - and β-adrenergic systems in the regulation of food intake in chickens. The significant (P ≤ 0.05) effect of i.c.v. injections of PROP (transient increase in water intake) implies a role of the adrenergic system, possibly via α-adrenoceptors, in the regulation of water intake in broilers, which is food intake-independent.Було досліджено впливи інтрацеребровентрикулярних мікроін’єкцій агоніста β-адренорецепторів ізопротеренолу та блокатора β-адренорецепторів пропранололу на споживання їжі та води бройлерами-півниками, позбавленими їжі та питва протягом 3 год. Виявилося, що ізопротеренол у концентрації 200 нM (але не менше) істотно (P ≤ 0.05) посилював споживання їжі, але не води. Пропранолол, ін’єкований у різних дозах (20–80 мкM), вірогідно зменшував споживання їжі. Отримані дані свідчать на користь гіпотез про орексигенну роль β₁ - та β₂-адренергічних систем у регуляції споживання їжі курчатами. Істотний (P ≤ 0.05) ефект ін’єкцій пропранололу (тимчасове зростання споживання води) вказує на певну роль адренергічної системи щодо регуляції споживання води бройлерами; цей ефект, вірогідно, реалізується через α-адренорецептори та є незалежним від впливів на споживання їжі

From Melanoma Development to RNA-Modified Dendritic Cell Vaccines: Highlighting the Lessons From the Past

Although melanoma remains the deadliest skin cancer, the current treatment has not resulted in the desired outcomes. Unlike chemotherapy, immunotherapy has provided more tolerable approaches and revolutionized cancer therapy. Although dendritic cell-based vaccines have minor side effects, the undesirable response rates of traditional approaches have posed questions about their clinical translation. The immunosuppressive tumor microenvironment can be the underlying reason for their low response rates. Immune checkpoints and indoleamine 2,3-dioxygenase have been implicated in the induction of immunosuppressive tumor microenvironment. Growing evidence indicates that the mitogen-activated protein kinase (MAPK) and phosphatidylinositol 3-kinase/Protein kinase B (PKB) (PI3K/AKT) pathways, as the main oncogenic pathways of melanoma, can upregulate the tumoral immune checkpoints, like programmed death-ligand 1. This study briefly represents the main oncogenic pathways of melanoma and highlights the cross-talk between these oncogenic pathways with indoleamine 2,3-dioxygenase, tumoral immune checkpoints, and myeloid-derived suppressor cells. Moreover, this study sheds light on a novel tumor antigen on melanoma, which has substantial roles in tumoral immune checkpoints expression, indoleamine 2,3-dioxygenase secretion, and stimulating the oncogenic pathways. Finally, this review collects the lessons from the previous unsuccessful trials and integrates their lessons with new approaches in RNA-modified dendritic cell vaccines. Unlike traditional approaches, the advances in single-cell RNA-sequencing techniques and RNA-modified dendritic cell vaccines along with combined therapy of the immune checkpoint inhibitors, indoleamine 2,3-dioxygenase inhibitor, and RNA-modified dendritic cell-based vaccine can overcome these auto-inductive loops and pave the way for developing robust dendritic cell-based vaccines with the most favorable response rate and the least side effects

Pancreatic cancer signaling pathways, genetic alterations, and tumor microenvironment: The barriers affecting the method of treatment

Genetic alterations, especially the K-Ras mutation, carry the heaviest burden in the progression of pancreatic precursor lesions into pancreatic ductal adenocarcinoma (PDAC). The tumor microenvironment is one of the challenges that hinder the therapeutic approaches from functioning sufficiently and leads to the immune evasion of pancreatic malignant cells. Mastering the mechanisms of these two hallmarks of PDAC can help us in dealing with the obstacles in the way of treatment. In this review, we have analyzed the signaling pathways involved in PDAC development and the immune system’s role in pancreatic cancer and immune checkpoint inhibition as next-generation therapeutic strategy. The direct targeting of the involved signaling molecules and the immune checkpoint molecules, along with a combination with conventional therapies, have reached the most promising results in pancreatic cancer treatment

Exact symmetry breaking ground states for quantum spin chains

We introduce a family of spin-1/2 quantum chains, and show that their exact ground states break the rotational and translational symmetries of the original Hamiltonian. We also show how one can use projection to construct a spin-3/2 quantum chain with nearest neighbor interaction, whose exact ground states break the rotational symmetry of the Hamiltonian. Correlation functions of both models are determined in closed form. Although we confine ourselves to examples, the method can easily be adapted to encompass more general models.Comment: 4 pages, RevTex. 4 figures, minor changes, new reference