Revealing the Singlet Fission Mechanism for a Silane-Bridged Thienotetracene Dimer.

Tetraceno[2,3-]thiophene is regarded as a strong candidate for singlet fission-based solar cell applications due to its mixed characteristics of tetracene and pentacene that balance exothermicity and triplet energy. An electronically weakly coupled tetraceno[2,3-]thiophene dimer (EtSi(TIPSTT)) with a single silicon atom bridge has been synthesized, providing a new platform to investigate the singlet fission mechanism involving the two acene chromophores. We study the excited state dynamics of EtSi(TIPSTT) by monitoring the evolution of multiexciton coupled triplet states, TT to TT to TT to T + S, upon photoexcitation with transient absorption, temperature-dependent transient absorption, and transient/pulsed electron paramagnetic resonance spectroscopies.

Entangled spin-polarized excitons from singlet fission in a rigid dimer.

Singlet fission, a process that splits a singlet exciton into a biexciton, has promise in quantum information. We report time-resolved electron paramagnetic resonance measurements on a conformationally well-defined acene dimer molecule, TIPS-BP1', designed to exhibit strongly state-selective relaxation to specific magnetic spin sublevels. The resulting optically pumped spin polarization is a nearly pure initial state from the ensemble.

Near-Infrared Absorption Features of Triplet-Pair States Assigned by Photoinduced-Absorption-Detected Magnetic Resonance.

Singlet fission proceeds through a manifold of triplet-pair states that are exceedingly difficult to distinguish spectroscopically. Here, we introduce a new implementation of photoinduced-absorption-detected magnetic resonance (PADMR) and use it to understand the excited-state absorption spectrum of a tri-2-pentylsilylethynyl pentadithiophene (TSPS-PDT) film. These experiments allow us to directly correlate magnetic transitions driven by RF with electronic transitions in the visible and near-infrared spectrum with high sensitivity.

Optical readout of singlet fission biexcitons in a heteroacene with photoluminescence detected magnetic resonance.

Molecular spin systems based on photoexcited triplet pairs formed via singlet fission (SF) are attractive as carriers of quantum information because of their potentially pure and controllable spin polarization, but developing systems that offer optical routes to readout as well as initialization is challenging. Herein, we characterize the electron spin magnetic resonance change in the photoluminescence intensity for a tailored organic molecular crystal while sweeping a microwave drive up to 10 GHz in a broadband loop structure. We observe resonant transitions for both triplet and quintet spin sublevel populations showing their optical sensitivity and revealing the zero-field parameters for each.

Long-Lived Mixed MLCT/MC States in Antiferromagnetically Coupled d Vanadium(II) Bipyridine and Phenanthroline Complexes.

Exploration of [V(bpy)] and [V(phen)] (bpy = 2,2'-bipyridine; phen = 1,10-phenanthroline) using electronic spectroscopy reveals an ultrafast excited-state decay process and implicates a pair of low-lying doublets with mixed metal-to-ligand charge-transfer (MLCT) and metal-centered (MC) character. Transient absorption (TA) studies of the vanadium(II) species probing in the visible and near-IR, in combination with spectroelectrochemical techniques and computational chemistry, lead to the conclusion that after excitation into the intense and broad visible MLCT ← GS (ground-state) absorption band (ε = 900-8000 M cm), the MLCT state rapidly (τ < 200 fs) relaxes to the upper of two doublet states with mixed MLCT/MC character. Electronic interconversion (τ ∼ 2.

Daily GRACE satellite data evaluate short-term hydro-meteorological fluxes from global atmospheric reanalyses.

Changes in terrestrial water storage as observed by the satellite gravity mission GRACE (Gravity Recovery and Climate Experiment) represent a new and completely independent way to constrain the net flux imbalance in atmospheric reanalyses. In this study daily GRACE gravity field changes are used for the first time to investigate high-frequency hydro-meteorological fluxes over the continents. Band-pass filtered water fluxes are derived from GRACE water storage time series by first applying a numerical differentiation filter and subsequent high-pass filtering to isolate fluxes at periods between 5 and 30 days corresponding to typical time-scales of weather system persistence at moderate latitudes.

The impact of motivational interviewing on self-perceived burden in patients receiving therapeutic plasma exchange.

Background: Autoimmune disorders and neurodegenerative disorders take a physical and emotional toll on patients that undergo therapeutic plasma exchange (TPE) treatments. Previous literature has shown that these patients may feel a greater sense of self-burden. Motivational Interviewing (MI) is a technique used in various settings that has the potential to decrease feelings of self-burden.

Role of Prolactin in Promotion of Immune Cell Migration into the Mammary Gland.

Immune cells in the mammary gland play a number of important roles, including protection against infection during lactation and, after passing into milk, modulation of offspring immunity. However, little is known about the mechanism of recruitment of immune cells to the lactating gland in the absence of infection. Given the importance of prolactin to other aspects of lactation, we hypothesized it would also play a role in immune cell recruitment.

Anti-metastatic outcome of isoform-specific prolactin receptor targeting in breast cancer.

Controversy exists concerning the role of the long prolactin receptor (PRLR) in the progression of breast cancer. By targeting pre-mRNA splicing, we succeeded in knocking down only the long PRLR in vivo, leaving the short forms unaffected. Using two orthotopic and highly-metastatic models of breast cancer, one of which was syngeneic (mouse 4T1) to allow assessment of tumor-immune interactions and one of which was endocrinologically humanized (human BT-474) to activate human PRLRs, we examined the effect of long PRLR knockdown on disease progression.

Subcutaneous administration of leptin normalizes fasting plasma glucose in obese type 2 diabetic UCD-T2DM rats.

Leptin has been shown to reduce hyperglycemia in rodent models of type 1 diabetes. We investigated the effects of leptin administration in University of California, Davis, type 2 diabetes mellitus (UCD-T2DM) rats, which develop adult-onset polygenic obesity and type 2 diabetes. Animals that had been diabetic for 2 mo were treated with s.

Engaging Client's Family and Friends in Online Counseling.

This paper describes how online counseling can be used to engage family members in the recovery of clients. The counselor guides the client and the family member separately through the stages of change, helping them commit to joint action. Each participant thinks through his/her concerns and the advantages of getting involved, each makes a specific commitment to working together under the guidance of the counselor.

Recovery of trout myocardial function following anoxia: preconditioning in a non-mammalian model.

Studies with mammals and birds clearly demonstrate that brief preexposure to oxygen deprivation can protect the myocardium from damage normally associated with a subsequent prolonged hypoxic/ischemic episode. However, is not known whether this potent mechanism of myocardial protection, termed preconditioning, exists in other vertebrates including fishes. In this study, we used an in situ trout (Oncorhynchus mykiss) working heart preparation at 10 degrees C to examine whether prior exposure to 5 min of anoxia (PO(2) < or = 5 mmHg) could reduce or eliminate the myocardial dysfunction that normally follows 15 min of anoxic exposure.

Aging and glucose transporter plasticity in response to hypobaric hypoxia.

In order to gain a better understanding of tissue plasticity with aging, we investigated the adaptive responses of young and adult animals to both 7 and 28 days of hypobaric hypoxia. Senescence is associated with a decreased tolerance to hypoxia that may be related to an age-associated decline in glucose transporter system plasticity. In addition, elucidation of the factors contributing to the decreased hypoxia tolerance with aging may provide insights into ischemia for older individuals.

Influence of physical activity on plasma insulin-like growth factor-1 and insulin-like growth factor binding proteins in healthy older women.

It was examined whether physical activity could alter the bioavailability of insulin-like growth factor-1 (IGF-1) which is dependent upon plasma IGF-1 and insulin-like growth factor binding protein (IGFBPs) levels. The potential role that growth hormone (GH) and insulin play in this process was also examined. Seven healthy 62-69-year-old women performed four bouts of physical activity on separate occasions at either a low (L; heart rate = 100 bpm) or moderate intensity (M; heart rate = 120 bpm) for either 25 (S) or 50 (L) min (LS, low intensity/short duration; LL, low intensity/long duration; MS, moderate intensity/short duration; ML, moderate intensity/long duration).

Myofibroblasts in phenytoin-induced hyperplastic connective tissue in the rat and in human gingival overgrowth.

Phenytoin is a commonly used anticonvulsant drug for the prevention of seizures. A common side effect of phenytoin (PHT) therapy is connective tissue hyperplasia, particularly in the oral cavity manifesting as gingival overgrowth. Our previous studies concerning the molecular mechanisms of drug-induced gingival overgrowth have demonstrated that PHT alters the normal tissue turnover/wound healing signal by causing changes in macrophage phenotype, resulting in the upregulation of essential polypeptide growth factors such as platelet-derived growth factor (PDGF).

Phenytoin and cyclosporine A specifically regulate macrophage phenotype and expression of platelet-derived growth factor and interleukin-1 in vitro and in vivo: possible molecular mechanism of drug-induced gingival hyperplasia.

Phenytoin (pht) is an anticonvulsant drug commonly used for the prevention of seizures. A common side effect of PHT therapy is gingival hyperplasia, occasionally so severe that it requires surgical intervention. Cyclosporine A (CSA) is a drug widely used for the control of rejection phenomena following solid organ and bone marrow transplantation.

Cyclosporine A upregulates platelet-derived growth factor B chain in hyperplastic human gingiva.

Cyclosporine A (CSA) is a widely used immunosuppressant for transplant patients and is also used for the treatment of a wide variety of systemic diseases with immunologic components. A prominent side effect of CSA administration is gingival overgrowth (hyperplasia). It has been postulated that CSA alters fibroblast activity through effects on various growth factors/cytokines.

PDGF-B producing cells and PDGF-B gene expression in normal gingival and cyclosporine A-induced gingival overgrowth.

It has been proposed that healthy gingiva is in a continuous state of wound repair. Thus, one might expect to find cells in normal gingiva producing growth factors associated with wound healing such as platelet-derived growth factor B chain (PDGF-B). One might also expect to find increased numbers of these cells or increased amounts of these growth factors in conditions which involve increased tissue volume such as drug-induced gingival overgrowth (DGO).

Platelet-derived growth factor levels in wounds of diabetic rats.

Delayed wound healing is a troublesome complication of Diabetes. Results from recent investigations concerning the potential cellular and molecular mechanisms responsible for diabetic wound healing deficiency are preliminary in nature. Some studies have demonstrated that direct application of certain growth factors/cytokines can facilitate wound healing in diabetic models.

Synthesis of platelet-derived growth factor by cells of splenic red pulp in normal rats.

A population of cells in the spleens of normal rats was found to contain platelet-derived growth factor (PDGF) B chain mRNA. These cells were found predominantly in the red pulp and nuclear morphology of some was consistent with that of macrophages. Similar cells were also shown by immunocytochemical staining to contain PDGF-AB/BB.

Phenytoin increases gene expression for platelet-derived growth factor B chain in macrophages and monocytes.

The mechanism by which phenytoin (PHT) induces gingival overgrowth remains unclear. We hypothesized that PHT increases macrophage production of platelet-derived growth factor (PDGF), an important cytokine in connective tissue growth and repair, and that excessive production PDGF in gingiva could lead to redundant growth. To test the hypothesis, rat peritoneal macrophages and human blood monocytes were cultured in the presence of PHT (5 to 20 micrograms/ml medium) or an equal volume of its solvent for 3 days and tested for expression of PDGF-B mRNA by in situ hybridization.

SAW devices for consumer communication applications.

An overview of surface acoustic wave (SAW) filter techniques available for different applications is given. Techniques for TV IF applications are outlined, and typical structures are presented. This is followed by a discussion of applications for SAW resonators.

Phenytoin-induced DNA synthesis and inositol 1,4,5-trisphosphate formation in L-929 fibroblasts.

Culture of L-929 fibroblasts in the presence of phenytoin (2.5-5.0 micrograms/ml) increased DNA synthesis, as indicated by increased [3H]thymidine uptake, while a higher dose (20 micrograms/ml) inhibited DNA synthesis.