Preferential localization of a vesicular monoamine transporter to dense core vesicles in PC12 cells.

Neurons and endocrine cells have two types of secretory vesicle that undergo regulated exocytosis. Large dense core vesicles (LDCVs) store neural peptides whereas small clear synaptic vesicles store classical neurotransmitters such as acetylcholine, gamma-aminobutyric acid (GABA), glycine, and glutamate. However, monoamines differ from other classical transmitters and have been reported to appear in both LDCVs and smaller vesicles. To localize the transporter that packages monoamines into secretory vesicles, we have raised antibodies to a COOH-terminal sequence from the vesicular amine transporter expressed in the adrenal gland (VMAT1). Like synaptic vesicle proteins, the transporter occurs in endosomes of transfected CHO cells, accounting for the observed vesicular transport activity. In rat pheochromocytoma PC12 cells, the transporter occurs principally in LDCVs by both immunofluorescence and density gradient centrifugation. Synaptic-like microvesicles in PC12 cells contain relatively little VMAT1. The results appear to account for the storage of monoamines by LDCVs in the adrenal medulla and indicate that VMAT1 provides a novel membrane protein marker unique to LDCVs

Low-operating-voltage polymer thin-film transistors based on poly(3-hexylthiophene) with hafnium oxide as the gate dielectric

The effects of hafnium oxide $(hbox{HfO}-{2})$ gate dielectric annealing treatment in oxygen $(hbox{O}-{2})$ and ammonia $(hbox{NH}-{3})$ ambient on the electrical performance of polymer thin-film transistors (PTFTs) based on poly(3-hexylthiophene) are investigated. The PTFTs with $hbox{HfO}-{2}$ gate dielectric and also octadecyltrichlorosilane surface modification, prepared by spin-coating process, exhibit good performance, such as a small threshold voltage of $-$0.5 V and an operating voltage as low as $-$4 V. Results indicate that the PTFT with $hbox{NH}-{3}$-annealed $hbox{HfO}-{2}$ shows higher carrier mobility, larger on/off current ratio, smaller subthreshold swing, and lower threshold voltage than the PTFT with $hbox{O}-{2}$-annealed $hbox{HfO}-{2}$. Capacitancevoltage analysis for metal-polymer-oxide-silicon structures indicates that the better electrical performance of the PTFT with $hbox{NH}-{3}$ -annealed $hbox{HfO}-{2}$ is attributed to improved dielectric/polymer interface and reduced series resistance in the transistor. © 2006 IEEE.published_or_final_versio

Bias-stress-induced instability of polymer thin-film transistor based on poly(3-hexylthiophene)

A polymer thin-film transistor (PTFT) based on poly(3-hexylthiophene) (P3HT) is fabricated by a spin-coating process and characterized. Its bias-stress-induced instability during operation is investigated as a function of time and temperature. For negative gate-bias stress, the carrier mobility remains unchanged, the off-state current decreases, and the threshold voltage shifts toward the negative direction. On the other hand, for negative drain-bias stress, the carrier mobility decreases slightly, the off-state current increases, and the threshold voltage shifts toward the positive direction. The threshold shifts under gate- and drain-bias stresses are observed to be logarithmically dependent on time, and the decay rate of the threshold-voltage shift is independent of temperature. The results suggest that the origin of the threshold-voltage shift upon negative gate-bias stress is predominantly associated with holes trapped within the SiO 2 gate dielectric or at the P3HT/SiO 2 interface, while time-dependent charge trapping in the deep trap states and creation of defect states in the channel region are responsible for the drain-bias stress effect on the PTFT. © 2011 IEEE.published_or_final_versio

Phytoplankton carbon fixation gene (RuBisCO) transcripts and air-sea CO2 flux in the Mississippi River plume

River plumes deliver large quantities of nutrients to oligotrophic oceans, often resulting in significant CO2 drawdown. To determine the relationship between expression of the major gene in carbon fixation (large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase, RuBisCO) and CO2 dynamics, we evaluated rbcL mRNA abundance using novel quantitative PCR assays, phytoplankton cell analyses, photophysiological parameters, and pCO2 in and around the Mississippi River plume (MRP) in the Gulf of Mexico. Lower salinity (30-32) stations were dominated by rbcL mRNA concentrations from heterokonts, such as diatoms and pelagophytes, which were at least an order of magnitude greater than haptophytes, a-Synechococcus or high-light Prochlorococcus. However, rbcL transcript abundances were similar among these groups at oligotrophic stations (salinity 34-36). Diatom cell counts and heterokont rbcL RNA showed a strong negative correlation to seawater pCO2. While Prochlorococcus cells did not exhibit a large difference between low and high pCO2 water, Prochlorococcus rbcL RNA concentrations had a strong positive correlation to pCO(2), suggesting a very low level of RuBisCO RNA transcription among Prochlorococcus in the plume waters, possibly due to their relatively poor carbon concentrating mechanisms (CCMs). These results provide molecular evidence that diatom/pelagophyte productivity is largely responsible for the large CO2 drawdown occurring in the MRP, based on the cooccurrence of elevated RuBisCO gene transcript concentrations from this group and reduced seawater pCO(2) levels. This may partly be due to efficient CCMs that enable heterokont eukaryotes such as diatoms to continue fixing CO2 in the face of strong CO2 drawdown. Our work represents the first attempt to relate in situ microbial gene expression to contemporaneous CO2 flux measurements in the ocean

Health Access Broker: Secure, Patient-Controlled Management of Personal Health Records in the Cloud

Secure and privacy-preserving management of Personal Health Records (PHRs) has proved to be a major challenge in modern healthcare. Current solutions generally do not offer patients a choice in where the data is actually stored and also rely on at least one fully trusted element that patients must also trust with their data. In this work, we present the Health Access Broker (HAB), a patient-controlled service for secure PHR sharing that (a) does not impose a specific storage location (uniquely for a PHR system), and (b) does not assume any of its components to be fully secure against adversarial threats. Instead, HAB introduces a novel auditing and intrusion-detection mechanism where its workflow is securely logged and continuously inspected to provide auditability of data access and quickly detect any intrusions.Comment: Copy of the paper accepted at 13th International Conference on Computational Intelligence in Security for Information Systems (CISIS

Development and implementation of Taiwan\u27s child health literacy test

Objectives: The aims of this study were to develop Taiwan\u27s Child Health Literacy Test and to undertake a nation-wide survey in order to determine the current status of Taiwanese sixth graders\u27 health literacy, and to understand the association between health literacy, healthy behavior, and health status. absp Methods: Taiwan\u27s Child Health Literacy Test was developed through the process of concept clarification, a qualitative pilot, a development pilot, and a field test. In the field test, 162,609 sixth graders (56.9%) from 2,235 schools (83.3%) nationwide completed the questionnaire. We also collected the students\u27 dates of birth, BMIs, self-reported health and healthy behaviors. absp Results: The final test consisted of 32 questions with item discrimination of 0.55-1.89 and item difficulty of-1.7-0.41 according to IRT; Cronbach\u27s a was 0.87. Based on this information, the test was deemed appropriate for basic health literacy screening among children. Nation-wide, the average score for sixth graders\u27 health literacy was 23.97 points (total score 32 points), with a correct rate of 74.9%. Those who were "good" in self-reported health scored highest in health literacy (M = 24.29). Health literacy was significantly positively related to healthy behavior (r = .25, p< .05), and negatively to risky behavior (r =-.28, p< .05). absp Conclusions: This study was the first curriculum-based child health literacy test developed from the viewpoints of both teachers and pupils in Taiwan through a rigorous procedure. The nationwide survey results may serve as a reference for decision-makers at the national health education level

At Least Bias Is Bipartisan: A Meta-Analytic Comparison of Partisan Bias in Liberals and Conservatives

Both liberals and conservatives accuse their political opponents of partisan bias, but is there empirical evidence that one side of the political aisle is indeed more biased than the other? To address this question, we meta-analyzed the results of 51 experimental studies, involving over 18,000 participants, that examined one form of partisan bias—the tendency to evaluate otherwise identical information more favorably when it supports one’s political beliefs or allegiances than when it challenges those beliefs or allegiances. Two hypotheses based on previous literature were tested: an asymmetry hypothesis (predicting greater partisan bias in conservatives than in liberals) and a symmetry hypothesis (predicting equal levels of partisan bias in liberals and conservatives). Mean overall partisan bias was robust (r = .245), and there was strong support for the symmetry hypothesis: Liberals (r = .235) and conservatives (r = .255) showed no difference in mean levels of bias across studies. Moderator analyses reveal this pattern to be consistent across a number of different methodological variations and political topics. Implications of the current findings for the ongoing ideological symmetry debate and the role of partisan bias in scientific discourse and political conflict are discussed

Inorganic speciation of dissolved elements in seawater: the influence of pH on concentration ratios

Assessments of inorganic elemental speciation in seawater span the past four decades. Experimentation, compilation and critical review of equilibrium data over the past forty years have, in particular, considerably improved our understanding of cation hydrolysis and the complexation of cations by carbonate ions in solution. Through experimental investigations and critical evaluation it is now known that more than forty elements have seawater speciation schemes that are strongly influenced by pH. In the present work, the speciation of the elements in seawater is summarized in a manner that highlights the significance of pH variations. For elements that have pH-dependent species concentration ratios, this work summarizes equilibrium data (S = 35, t = 25°C) that can be used to assess regions of dominance and relative species concentrations. Concentration ratios of complex species are expressed in the form log[A]/[B] = pH - C where brackets denote species concentrations in solution, A and B are species important at higher (A) and lower (B) solution pH, and C is a constant dependent on salinity, temperature and pressure. In the case of equilibria involving complex oxy-anions (MO(x)(OH)(y)) or hydroxy complexes (M(OH)(n)), C is written as pK(n )= -log K(n )or pK(n)* = -log K(n)* respectively, where K(n )and K(n)* are equilibrium constants. For equilibria involving carbonate complexation, the constant C is written as pQ = -log(K(2)(l)K(n )[HCO(3)(-)]) where K(2)(l )is the HCO(3 )(- )dissociation constant, K(n )is a cation complexation constant and [HCO(3)(-)] is approximated as 1.9 × 10(-3 )molar. Equilibrium data expressed in this manner clearly show dominant species transitions, ranges of dominance, and relative concentrations at any pH

Mechanical Metamaterials with Negative Compressibility Transitions

When tensioned, ordinary materials expand along the direction of the applied force. Here, we explore network concepts to design metamaterials exhibiting negative compressibility transitions, during which a material undergoes contraction when tensioned (or expansion when pressured). Continuous contraction of a material in the same direction of an applied tension, and in response to this tension, is inherently unstable. The conceptually similar effect we demonstrate can be achieved, however, through destabilisations of (meta)stable equilibria of the constituents. These destabilisations give rise to a stress-induced solid-solid phase transition associated with a twisted hysteresis curve for the stress-strain relationship. The strain-driven counterpart of negative compressibility transitions is a force amplification phenomenon, where an increase in deformation induces a discontinuous increase in response force. We suggest that the proposed materials could be useful for the design of actuators, force amplifiers, micro-mechanical controls, and protective devices.Comment: Supplementary information available at http://www.nature.com/nmat/journal/v11/n7/abs/nmat3331.htm

Low-Voltage Continuous Electrospinning Patterning

Electrospinning is a versatile technique for the construction of microfibrous and nanofibrous structures with considerable potential in applications ranging from textile manufacturing to tissue engineering scaffolds. In the simplest form, electrospinning uses a high voltage of tens of thousands volts to draw out ultrafine polymer fibers over a large distance. However, the high voltage limits the flexible combination of material selection, deposition substrate, and control of patterns. Prior studies show that by performing electrospinning with a well-defined "near-field" condition, the operation voltage can be decreased to the kilovolt range, and further enable more precise patterning of fibril structures on a planar surface. In this work, by using solution dependent "initiators", we demonstrate a further lowering of voltage with an ultralow voltage continuous electrospinning patterning (LEP) technique, which reduces the applied voltage threshold to as low as 50 V, simultaneously permitting direct fiber patterning. The versatility of LEP is shown using a wide range of combination of polymer and solvent systems for thermoplastics and biopolymers. Novel functionalities are also incorporated when a low voltage mode is used in place of a high voltage mode, such as direct printing of living bacteria; the construction of suspended single fibers and membrane networks. The LEP technique reported here should open up new avenues in the patterning of bioelements and free-form nano- to microscale fibrous structures.Studentship and scholarship funding supports from the China Scholarship Council scholarship, EPSRC doctoral training partnership, Schlumberger Foundation, WD Armstrong Trus