Structure and energetics of helium adsorption on nanosurfaces

The ground and excited state properties of small helium clusters, 4He_N, containing nanoscale (~3-10 Angstroms) planar aromatic molecules have been studied with quantum Monte Carlo methods. Ground state structures and energies are obtained from importance-sampled, rigid-body diffusion Monte Carlo. Excited state energies due to helium vibrational motion are evaluated using the projection operator, imaginary time spectral evolution technique. We examine the adsorption of N helium atoms (N less than or equal to 24) on a series of planar aromatic molecules (benzene, naphthalene, anthracene, tetracene, phthalocyanine). The first layer of helium atoms is well-localized on the molecule surface, and we find well-defined localized excitations due to in-plane vibrational motion of helium on the molecule surface. We discuss the implications of these confined excitations for the molecule spectroscopy.Comment: 6 pages, 2 figures, QFS 2003 Symposium, submitted to J. Low Temp. Phy

Temperature, light and nitrate sensing coordinate Arabidopsis seed dormancy cycling resulting in winter and summer annual phenotypes

Seeds use environmental cues to sense the seasons and their surroundings to initiate the plants life cycle. Dormancy cycling underlying this process is extensively described, but the molecular mechanism is largely unknown. To address this we selected a range of representative genes from published array experiments in the laboratory and investigated their expression patterns in seeds of Arabidopsis ecotypes, having contrasting life cycles, over an annual dormancy cycle in the field. We show how mechanisms identified in the laboratory are coordinated in response to the soil environment to determine dormancy cycles that result in winter and summer annual phenotypes. Our results are consistent with a seed specific response to seasonal temperature patterns (temporal sensing) involving the gene DELAY OF GERMINATION1 (DOG1) that indicates the correct season; and concurrent temporally driven co-opted mechanisms that sense spatial signals i.e. nitrate via CBL-INTERACTING PROTEIN KINASE 23 (CIPK23) phosphorylation of the NITRATE TRANSPORTER 1 (NRT1.1) and light via PHYTOCHROME A (PHYA). In both ecotypes studied, when all three genes have low expression there is enhanced GIBBERELLIN 3 BETA-HYDROXYLASE 1 (GA3ox1) expression, exhumed seeds have the potential to germinate in the laboratory, and the initiation of seedling emergence occurs following soil disturbance (exposure to light) in the field. Unlike DOG1, expression of MOTHER of FLOWERING TIME (MFT) has an opposite thermal response in seeds of the two ecotypes indicating a role in determining their different dormancy cycling phenotypes

A designed protein interface that blocks fibril formation

Protein fibril formation is implicated in many diseases, and therefore much effort has been focused toward the development of inhibitors of this process. In a previous project, a monomeric protein was computationally engineered to bind itself and form a heterodimer complex following interfacial redesign. One of the protein monomers, termed monomer-B, was unintentionally destabilized and shown to form macroscopic fibrils. Interestingly, in the presence of the designed binding partner, fibril formation was blocked. Here we describe the complete characterization of the amyloid properties of monomer-B and the inhibition of fiber formation by the designed binding partner, monomer-A. Both proteins are mutants of the betal domain of streptococcal protein-G. The free monomer-B protein forms amyloid-type fibrils, as determined by transmission electron microscopy and the change in fluorescence of Thioflavin T, an amyloid-specific dye. Fibril formation kinetics are influenced by pH, protein concentration, and seeding with preformed fibrils. Under all conditions tested, monomer-A was able to inhibit the formation of monomer-B fibrils. This inhibition is specific to the engineered interaction, as incubation of monomer-B with wild-type protein-G (a structural homologue) did not result in inhibition under the same conditions. Thus, this de novo-designed heterodimeric complex is an excellent model system for the study of protein-based fibril formation and inhibition. This system provides additional insight into the development of pharmaceuticals for amyloid disorders, as well as the potential use of amyloid fibrils for self-assembling nanostructures

Normal sleep bouts are not essential for C. elegans survival and FoxO is important for compensatory changes in sleep

Additional file 6: Decreased lag-2 function does not slow vulval development. The progeny of wild type and lag-2(q420) animals raised at 25.5 °C were selected at the L4 stage, prior to lethargus entry. Vulval eversion was scored after 3 h; the percentage of animals completing vulval eversion was recorded. Significance was assessed by student’s two-tailed t-test p value < 0.5; error bars represents SEM from 3 trials. Total number of animals: wild type n = 45 and lag-2(q420) n = 42

Retrieval cues fail to influence contextualized evaluations.

Initial evaluations generalise to new contexts, whereas counter-attitudinal evaluations are context-specific. Counter-attitudinal information may not change evaluations in new contexts because perceivers fail to retrieve counter-attitudinal cue-evaluation associations from memory outside the counter-attitudinal learning context. The current work examines whether an additional, counter-attitudinal retrieval cue can enhance the generalizability of counter-attitudinal evaluations. In four experiments, participants learned positive information about a target person, Bob, in one context, and then learned negative information about Bob in a different context. While learning the negative information, participants wore a wristband as a retrieval cue for counter-attitudinal Bob-negative associations. Participants then made speeded as well as deliberate evaluations of Bob while wearing or not wearing the wristband. Internal meta-analysis failed to find a reliable effect of the counter-attitudinal retrieval cue on speeded or deliberate evaluations, whereas the context cues influenced speeded and deliberate evaluations. Counter to predictions, counter-attitudinal retrieval cues did not disrupt the generalisation of first-learned evaluations or the context-specificity of second-learned evaluations (Experiments 2-4), but the counter-attitudinal retrieval cue did influence evaluations in the absence of context cues (Experiment 1). The current work provides initial evidence that additional counter-attitudinal retrieval cues fail to disrupt the renewal and generalizability of first-learned evaluations

Osteoblast differentiation and migration are regulated by Dynamin GTPase activity

Bone formation is controlled by osteoblasts but the signaling proteins that control osteoblast differentiation and function are still unclear. We examined if the dynamin GTPase, which is associated with actin remodeling and migration in other cells, plays a role in osteoblast differentiation and migration. Dynamin mRNA was expressed in primary osteoblasts throughout differentiation (0–21 days). However, alkaline phosphatase (ALP) activity, a marker of osteoblast differentiation, was decreased in osteoblasts over-expressing dynamin. Conversely, ALP activity was increased following shRNA-mediated knockdown of dynamin and in osteoblasts treated with the dynamin inhibitor, dynasore. Dynasore also reduced c-fos and osterix expression, markers of early osteoblasts, suggesting a role for dynamin in pre-osteoblast to osteoblast differentiation. Since dynamin GTPase activity is regulated by tyrosine phosphorylation, we examined the mechanism of dynamin dephosphorylation in osteoblasts. Dynamin formed a protein complex with the tyrosine phosphatase PTP-PEST and inhibition of phosphatase activity increased the level of phosphorylated dynamin. Further, PTP-PEST blocked the Src-mediated increase in the phosphorylation and GTPase activity of wild-type dynamin but not the phosphorylation mutant dynY231F/Y597F. Although ALP activity was increased in osteoblasts expressing GTPase-defective dynK44A, and to a lesser extent dynY231F/Y597F, osteoblast migration was significantly inhibited by dynK44A and dynY231F/Y597F. These studies demonstrate a novel role for dynamin GTPase activity and phosphorylation in osteoblast differentiation and migration, which may be important for bone formation

Characteristics of multi-institutional health sciences education research: a systematic review

Objectives: Multi-institutional research increases the generalizability of research findings. However, little is known about characteristics of collaborations across institutions in health sciences education research. Using a systematic review process, the authors describe characteristics of published, peer-reviewed multi-institutional health sciences education research to inform educators who are considering such projects. Methods: Two medical librarians searched MEDLINE, the Education Resources Information Center (ERIC), EMBASE, and CINAHL databases for English-language studies published between 2004 and 2013 using keyword terms related to multi-institutional systems and health sciences education. Teams of two authors reviewed each study and resolved coding discrepancies through consensus. Collected data points included funding, research network involvement, author characteristics, learner characteristics, and research methods. Data were analyzed using descriptive statistics. Results: One hundred eighteen of 310 articles met inclusion criteria. Sixty-three (53%) studies received external and/or internal financial support (87% listed external funding, 37% listed internal funding). Forty-five funded studies involved graduate medical education programs. Twenty (17%) studies involved a research or education network. Eighty-five (89%) publications listed an author with a master’s degree or doctoral degree. Ninety-two (78%) studies were descriptive, whereas 26 studies (22%) were experimental. The reported study outcomes were changes in student attitude (38%; n=44), knowledge (26%; n=31), or skill assessment (23%; n=27), as well as patient outcomes (9%; n=11). Conclusions: Multi-institutional descriptive studies reporting knowledge or attitude outcomes are highly published. Our findings indicate that funding resources are not essential to successfully undertake multi-institutional projects. Funded studies were more likely to originate from graduate medical or nursing programs

Known-groups validity of the Patient-Reported Outcomes Measurement Information System (PROMIS®) in adolescents and young adults with special healthcare needs

To examine known-groups validity of the Patient-Reported Outcomes Measurement Information System (PROMIS®) Short Forms (SFs) for adolescents and young adults with special health care needs (SHCN) using data collected from the PROMIS Linking Study

Risk Factors for Urgency Incontinence in Women Undergoing Stress Urinary Incontinence Surgery

Objective. To determine baseline variables associated with urgency urinary incontinence (UUI) in women presenting for stress urinary incontinence (SUI) surgery. Methods. Baseline data from two randomized trials enrolling 1,252 women were analyzed: SISTEr (fascial sling versus Burch colposuspension) and TOMUS (retropubic versus transobturator midurethral sling). Demographic data, POP-Q measures, and validated measures of symptom severity and quality of life were collected. Charlson Comorbidity Index (CCI) and Patient Health Questionnaire-9 were measured in TOMUS. Multivariate models were constructed with UUI and symptom severity as outcomes. Results. Over two-thirds of subjects reported bothersome UUI at baseline. TOMUS patients with more comorbidities had higher UDI irritative scores (CCI score 0 = 39.4, CCI score 1 = 42.1, and CCI score 2+ = 51.0, P=0.0003), and higher depression scores were associated with more severe UUI. Smoking, parity, prior incontinence surgery/treatment, prolapse stage, and incontinence episode frequency were not independently associated with UUI. Conclusions. There were no modifiable risk factors identified for patient-reported UUI in women presenting for SUI surgery. However, the direct relationships between comorbidity level, depression, and worsening of UUI/urgency symptoms may represent targets for preoperative intervention. Further research is necessary to elucidate the pathophysiologic mechanisms that explain the associations between these medical conditions and bladder function