Searching for Chameleon Dark Energy with Mechanical Systems.

A light scalar field framework of dark energy, sometimes referred to as quintessence, introduces a fifth force between normal matter objects. Screening mechanisms, such as the chameleon model, allow the scalar field to be almost massless on cosmological scales while simultaneously evading laboratory constraints. We explore the ability of existing mechanical systems to directly detect the fifth force associated with chameleons in an astrophysically viable regime where it could be dark energy. We provide analytical expressions for the weakest accessible chameleon model parameters in terms of experimentally tunable variables and apply our analysis to two mechanical systems: levitated microspheres and torsion balances, showing that the current generation of these experiments have the sensitivity to rule out a significant portion of the proposed chameleon parameter space. We also indicate regions of theoretically well-motivated chameleon parameter space to guide future experimental work.

Developmental Ethanol-Induced Sleep Fragmentation, Behavioral Hyperactivity, Cognitive Impairment and Parvalbumin Cell Loss are Prevented by Lithium Co-treatment.

Developmental ethanol exposure is a well-known cause of lifelong cognitive deficits, behavioral hyperactivity, emotional dysregulation, and more. In healthy adults, sleep is thought to have a critical involvement in each of these processes. Our previous work has demonstrated that some aspects of cognitive impairment in adult mice exposed at postnatal day 7 (P7) to ethanol (EtOH) correlate with slow-wave sleep (SWS) fragmentation (Wilson et al., 2016). We and others have also previously demonstrated that co-treatment with LiCl on the day of EtOH exposure prevents many of the anatomical and physiological impairments observed in adults. Here we explored cognitive function, diurnal rhythms (activity, temperature), SWS, and parvalbumin (PV) and perineuronal net (PNN)-positive cell densities in adult mice that had received a single day of EtOH exposure on P7 and saline-treated littermate controls. Half of the animals also received a LiCl injection on P7. The results suggest that developmental EtOH resulted in adult behavioral hyperactivity, cognitive impairment, and reduced SWS compared to saline controls. Both of these effects were reduced by LiCl treatment on the day of EtOH exposure. Finally, developmental EtOH resulted in decreased PV/PNN-expressing cells in retrosplenial (RS) cortex and dorsal CA3 hippocampus at P90. As with sleep and behavioral activity, LiCl treatment reduced this decrease in PV expression. Together, these results further clarify the long-lasting effects of developmental EtOH on adult behavior, physiology, and anatomy. Furthermore, they demonstrate the neuroprotective effects of LiCl co-treatment on this wide range of developmental EtOH's long-lasting consequences.

Approaches by the US National Institutes of Health to support rigorous scientific research on dietary supplements and natural products.

Mechanistic, clinical, and epidemiological research relevant to dietary supplements (DS) is supported by the U.S. National Institutes of Health. The Office of Dietary Supplements and the National Center for Complementary and Integrative Health promote the development and appropriate use of rigorous and comprehensive DS analyses which are critical for research reproducibility, particularly when the investigational DS include chemically complex natural products with unclear mechanisms of action.

The development and implementation of quality assurance programs to support nutritional measurements.

The National Institute of Standards and Technology administers quality assurance programs devoted to improving measurements of nutrients and related metabolites in foods, dietary supplements, and serum and plasma samples. These programs have been developed in collaboration with the National Institutes of Health to assist measurement communities in their efforts to achieve accurate results that are comparable among different laboratories and over time. Targeted analytes include micronutrients, botanical markers, nutritional elements, contaminants, fatty acids, and vitamin D metabolites.

Development and certification of green tea-containing standard reference materials.

A suite of three green tea-containing Standard Reference Materials (SRMs) has been issued by the National Institute of Standards and Technology (NIST): SRM 3254 Camellia sinensis (Green Tea) Leaves, SRM 3255 Camellia sinensis (Green Tea) Extract, and SRM 3256 Green Tea-Containing Solid Oral Dosage Form. The materials are characterized for catechins, xanthine alkaloids, theanine, and toxic elements. As many as five methods were used in assigning certified and reference values to the constituents, with measurements carried out at NIST and at collaborating laboratories. The materials are intended for use in the development and validation of new analytical methods, and for use as control materials as a component in the support of claims of metrological traceability.

Certification of vitamins and carotenoids in SRM 3280 multivitamin/multielement tablets.

A new multivitamin/multielement dietary supplement Standard Reference Material (SRM) has been issued by the National Institute of Standards and Technology (NIST), with certified and reference concentration values for 13 vitamins, 24 elements, and 2 carotenoids. The constituents have been measured by multiple analytical methods with data contributed by NIST and by collaborating laboratories. This effort included the first use of isotope dilution mass spectrometry for value assignment of both fat-soluble vitamins (FSVs) and water-soluble vitamins (WSVs). Excellent agreement was obtained among the methods, with relative expanded uncertainties for the certified concentration values typically ranging from <2% to 15% for vitamins.

Computed tomographic angiography versus conventional angiography for the diagnosis of blunt cerebrovascular injury in trauma patients.

BACKGROUND: Blunt cerebrovascular injuries (BCVI) in trauma patients are rare but potentially devastating injuries, particularly if the diagnosis is delayed. Conventional angiography (CA) has been the screening and diagnostic modality of choice for identifying BCVI. With the advent of high-resolution computed tomography (CT), CT angiography has become a common modality for the screening of BCVI. A liberalized screening approach has suggested that cerebrovascular injuries are missed in many patients; however, no standard BCVI screening protocol exists. Early diagnosis of the BCVI can prevent long-term sequelae. METHODS: In this prospective study, all patients received a CT angiogram (16-slice or 64-slice) at the time of injury assessment and followed 24 hours to 48 hours later with CA of the cerebrovasculature. RESULTS: A total of 158 patients were enrolled in the study. CA identified 32 injuries to the cerebrovasculature in 27 patients; CT detected only 13 true injuries (40.6%) in 12 patients. Of the 32 injuries, 11 were carotid artery injuries and 21 were of the vertebral artery. Seventy-four patients were screened with the 16-slice CT scanner with an overall sensitivity of 29%, and 84 patients were screened with the 64-slice CT scanner with an overall sensitivity of 54%. The combined specificity and sensitivity of 16- and 64-slice CT in detecting BCVI were 0.97 (95% confidence interval: 0.92-0.99) and 0.41 (95% confidence interval: 0.22-0.61), respectively. CONCLUSION: Neither 16- nor 64-slice CT angiography is as accurate as CA as a screening tool for BCVI.

Certification of standard reference materials containing bitter orange.

A suite of three dietary supplement standard reference materials (SRMs) containing bitter orange has been developed, and the levels of five alkaloids and caffeine have been measured by multiple analytical methods. Synephrine, octopamine, tyramine, N-methyltyramine, hordenine, total alkaloids, and caffeine were determined by as many as six analytical methods, with measurements performed at the National Institute of Standards and Technology and at two collaborating laboratories. The methods offer substantial independence, with two types of extractions, two separation methods, and four detection methods. Excellent agreement was obtained among the measurements, with data reproducibility for most methods and analytes better than 5% relative standard deviation. The bitter-orange-containing dietary supplement SRMs are intended primarily for use as measurement controls and for use in the development and validation of analytical methods.

Thermocapillary convection around gas bubbles: an important natural effect for the enhancement of heat transfer in liquids under microgravity.

In the presence of a temperature gradient at a liquid-gas or liquid-liquid interface, thermocapillary or Marangoni convection develops. This convection is a special type of natural convection that was not paid much attention in heat transfer for a long time, although it is strong enough to drive liquids against the direction of buoyancy on Earth. In a microgravity environment, however, it is the remaining mode of natural convection and supports heat and mass transfer. During boiling in microgravity it was observed at subcooled liquid conditions. Therefore, the question arises about its contribution to heat transfer without phase change. Thermocapillary convection was quantitatively studied at single gas bubbles in various liquids, both experimentally and numerically. A two-dimensional mathematical model described in this article was developed. The coupled mechanism of heat transfer and fluid flow in pure liquids around a single gas bubble was simulated with a control-volume FE-method. The simulation was accompanied and compared with experiments on Earth. The numerical results are in good accordance with the experiments performed on Earth at various Marangoni numbers using various alcohols of varying chain length and Prandtl numbers. As well as calculations on Earth, the numerical method also allows simulations at stationary spherical gas bubbles in a microgravity environment. The results demonstrate that thermocapillary convection is a natural heat transfer mechanism that can partially replace the buoyancy in a microgravity environment, if extreme precautions are taken concerning the purity of the liquids, because impurities accumulate predominantly at the interface. Under Earth conditions, an enhancement of the heat transfer in a liquid volume is even found in the case where thermocapillary flow is counteracted by buoyancy. In particular, the obstructing influence of surface active substances could be observed during the experiments on Earth in water and also in some cases with alcohols.

Phenotypic analysis of Paf1/RNA polymerase II complex mutations reveals connections to cell cycle regulation, protein synthesis, and lipid and nucleic acid metabolism.

Paf1 is an RNA polymerase II-associated protein in yeast, which defines a complex that is distinct from the Srb/Mediator holoenzyme. The Paf1 complex, which also contains Ctr9, Cdc73, Hpr1, Ccr4, Rtf1 and Leo1, is required for full expression of a subset of yeast genes, particularly those responsive to signals from the Pkc1/MAP kinase cascade. We have extensively characterized the pleiotropic phenotypes of deletion mutants for factors present in the Paf1 complex, identifying more than a dozen new phenotypes, and, in some cases, establishing possible molecular explanations for the growth defects. For example, paf1 Delta causes sensitivity to hydroxyurea; this phenotype correlates with a reduction in RNR1 transcript abundance and is suppressed by over-expression of RNR1. In contrast, the resistance of paf1 Delta cells to the transcription elongation inhibitors 6-azauracil and mycophenolic acid correlates with its ability to derepress the IMD2 transcript. We tested the hypothesis that Paf1 communicates with some promoters through the DNA-binding factors Swi4, Mbp1 or Rlm1. The phenotypes of mutations in Paf1 complex components are exacerbated in the swi4 Delta background, suggesting that the complex acts in a pathway parallel to that controlled by Swi4. Conversely, the fact that mbp1 Delta and rlm1 Delta mutations do not enhance the phenotypes suggests that the Paf1 complex may function in the same regulatory pathway(s) with Mbp1 and Rlm1.

A hybrid model of categorization.

Category learning is often modeled as either an exemplar-based or a rule-based process. This paper shows that both strategies can be combined in a cognitive architecture that was developed to model other task domains. Variations on the exemplar-based random walk (EBRW) model of Nosofsky and Palmeri (1997b) and the rule-plus-exception (RULEX) rule-based model of Nosofsky, Palmeri, and McKinley (1994) were implemented in the ACT-R cognitive architecture. The architecture allows the two strategies to be mixed to produce classification behavior. The combined system reproduces latency, learning, and generalization data from three category-learning experiments--Nosofsky and Palmeri (1997b), Nosofsky et al., and Erickson and Kruschke (1998). It is concluded that EBRW and ACT-R have different but equivalent means of incorporating similarity and practice. In addition, ACT-R brings a theory of strategy selection that enables the exemplar and the rule-based strategies to be mixed.

Solution and solid-state structure of (1-methoxy-8-naphthyllithium. THF)(2)

The structure of (1-methoxy-8-naphthyllithium.THF)(2), (2.THF)(2), determined by single-crystal X-ray diffraction (crystal data: monoclinic, a = 8.1816 (5), b = 21.9649 (14), and c = 8.2345 (3) A, beta = 117.969 (3) degrees; V = 1306.97 (12) A(3); space group P2(1)/n; Z = 4) reveals a centrosymmetrical dimer with a twist angle of about 63 degrees between the naphthyl rings and the Li-C(ipso)-Li plane, representing an intermediate between perpendicular and planar tetracoordinated C(ipso). NMR studies at low temperature indicate that 2 is dimeric in THF-d(8) solution under these conditions.

Detecting potential teratogenic alkaloids from blue cohosh rhizomes using an in vitro rat embryo culture.

The novel alkaloid thalictroidine (1), as well as the known alkaloids taspine (2), magnoflorine (3), anagyrine (4), baptifoline (5), 5,6-dehydro-alpha-isolupanine (6), alpha-isolupanine (7), lupanine (8), N-methylcytisine (9), and sparteine (10), were identified from an extract of Caulophyllum thalictroides rhizomes. N-Methylcytisine exhibited teratogenic activity in the rat embryo culture (REC), an in vitro method to detect potential teratogens. The structure of 1 was elucidated using various spectroscopic methods, primarily by NMR techniques. Thalictroidine, anagyrine, and alpha-isolupanine were not teratogenic in the REC at tested concentrations. Taspine (2) showed high embryotoxicity, but no teratogenic activity, in the REC.

Determination of salicin and related compounds in botanical dietary supplements by liquid chromatography with fluorescence detection.

A sensitive and reliable method is described for quantitative determination of salicin (including salicyl alcohol) and salicylic acid in botanical dietary supplements by reversed-phase liquid chromatography (LC) with wavelength-programmed fluorescence detection. One gram sample material was extracted with 20 mL aqueous phosphate buffer (pH 5.0), which was heated in an 80 degrees C water bath for 30 min. After centrifugation and cooling of the extract to room temperature, the supernatant was diluted with additional buffer. A 1 mL portion of diluted extract was mixed with 1 mL beta-glucosidase solution (2 mg/mL) and incubated for 40 min in a 37 degrees C water bath. The extract was passed through a 0.45 micron syringe filter and analyzed by LC. Limits of quantitation for salicin and salicylic acid were 20 and 1 microgram/g, respectively. Recoveries from samples fortified with salicin at 20, 100, and 1000 micrograms/g and with salicylic acid at 5, 20, and 50 micrograms/g ranged from 85 to 110%, with standard deviations less than 7%.