bluuebunny/crossref_metadata_2025 huggingface dataset:
Dendritic Cell–MHC Class II and Itk Regulate Functional Development of Regulatory Innate Memory CD4+ T Cells in Bone Marrow Transplantation
Authors: Huang Weishan , Qi Qian , Hu Jianfang , Huang Fei , Laufer Terri M. , August Avery
Published: March 2014

MHC class II (MHCII)–influenced CD4+ T cell differentiation and function play critical roles in regulating the development of autoimmunity. The lack of hematopoietic MHCII causes autoimmune disease that leads to severe wasting in syngeneic recipients. Using murine models of bone marrow transplantation (BMT), we find that MHCII−/−→wild-type BMT developed disease, with defective development of innate memory phenotype (IMP, CD44hi/CD62Llo) CD4+ T cells. Whereas conventional regulatory T cells are unable to suppress pathogenesis, IMP CD4+ T cells, which include conventional regulatory T cells, can suppress pathogenesis in MHCII−/−→wild-type chimeras. The functional development of IMP CD4+ T cells requires hematopoietic but not thymic MHCII. B cells and hematopoietic CD80/86 regulate the population size, whereas MHCII expression by dendritic cells is sufficient for IMP CD4+ T cell functional development and prevention of pathogenesis. Furthermore, the absence of Tec kinase IL-2–inducible T cell kinase in MHCII−/− donors leads to preferential development of IMP CD4+ T cells and partially prevents pathogenesis. We conclude that dendritic cells-MHCII and IL-2–inducible T cell kinase regulate the functional development of IMP CD4+ T cells, which suppresses the development of autoimmune disorder in syngeneic BMTs.
Henry's law constants of diacids and hydroxy polyacids: recommended values
Authors: Compernolle S. , Müller J.-F.
Published: March 2014

Abstract. In spite of the importance of diacids and functionalised diacids for organic aerosol formation through aqueous-phase processes in droplets and aerosol water, there seems to be no reliable set of experimental values for their Henry's law constants (HLCs). We show that their estimation through the use of infinite dilution activity coefficients is also prone to error. Here we present HLC values for diacids and hydroxy polyacids determined from solubilities, water activities and vapour pressures of solids or solutions, by employing thermodynamic relationships. The vapour pressures are found to be the largest source of error, but the analysis of the obtained HLC points to inconsistencies among specific vapour pressure data sets. Although there is considerable uncertainty, the HLC defined as aqueous concentration per unit gaseous partial pressure of linear α- and ω-diacids appear to be higher than estimated by the often cited review work of Saxena and Hildemann (1996).
Climatology of stratocumulus cloud morphologies: microphysical properties and radiative effects
Authors: Muhlbauer A. , McCoy I. L. , Wood R.
Published: March 2014

Abstract. An artificial neural network cloud classification scheme is combined with A-Train observations to characterize the physical properties and radiative effects of marine low clouds based on their morphology and type of mesoscale cellular convection (MCC) on a global scale. The cloud morphological categories are (i) organized closed MCC, (ii) organized open MCC and (iii) cellular but disorganized MCC. Global distributions of the frequency of occurrence of MCC types show clear regional signatures. Organized closed and open MCCs are most frequently found in subtropical regions and in mid-latitude storm tracks of both hemispheres. Cellular but disorganized MCC are the predominant type of marine low clouds in regions with warmer sea surface temperature such as in the tropics and trade wind zones. All MCC types exhibit a pronounced seasonal cycle. The physical properties of MCCs such as cloud fraction, radar reflectivity, drizzle rates and cloud top heights as well as the radiative effects of MCCs are found highly variable and a function of the type of MCC. On a global scale, the cloud fraction is largest for closed MCC with mean cloud fractions of about 90% whereas cloud fractions of open and cellular but disorganized MCC are only about 51% and 40%, respectively. Probability density functions (PDFs) of cloud fractions are heavily skewed and exhibit modest regional variability. PDFs of column maximum radar reflectivities and inferred cloud base drizzle rates indicate fundamental differences in the cloud and precipitation characteristics of different MCC types. Similarly, the radiative effects of MCCs differ substantially from each other in terms of shortwave reflectance and transmissivity. These differences highlight the importance of low cloud morphologies and their associated cloudiness on the shortwave cloud forcing.
Calibrating airborne measurements of airspeed, pressure and temperature using a Doppler laser air-motion sensor
Authors: Cooper W. A. , Spuler S. M. , Spowart M. , Lenschow D. H. , Friesen R. B.
Published: March 2014

Abstract. A new laser air-motion sensor measures the true airspeed with an uncertainty of less than 0.1 m s−1 (standard error) and so reduces uncertainty in the measured component of the relative wind along the longitudinal axis of the aircraft to about the same level. The calculated pressure expected from that airspeed at the inlet of a pitot tube then provides a basis for calibrating the measurements of dynamic and static pressure, reducing standard-error uncertainty in those measurements to less than 0.3 hPa and the precision applicable to steady flight conditions to about 0.1 hPa. These improved measurements of pressure, combined with high-resolution measurements of geometric altitude from the Global Positioning System, then indicate (via integrations of the hydrostatic equation during climbs and descents) that the offset and uncertainty in temperature measurement for one research aircraft are +0.3 ± 0.3 °C. For airspeed, pressure and temperature these are significant reductions in uncertainty vs. those obtained from calibrations using standard techniques. Finally, it is shown that the new laser air-motion sensor, combined with parametrized fits to correction factors for the measured dynamic and ambient pressure, provides a measurement of temperature that is independent of any other temperature sensor.
Sudden cold temperature delays plant carbon transport and shifts allocation from growth to respiratory demand
Authors: Barthel M. , Cieraad E. , Zakharova A. , Hunt J. E.
Published: March 2014

Abstract. Since substrates for respiration are supplied mainly by recent photo-assimilates, there is a strong but time-lagged link between short-term above- and belowground carbon (C) cycling. However, regulation of this coupling by environmental variables is poorly understood. Whereas recent studies focussed on the effect of drought and shading on the link between above- and belowground short-term C cycling, the effect of temperature remains unclear. We used a 13CO2 pulse-chase labelling experiment to investigate the effect of a sudden temperature change from 25 to 10 °C on the short-term coupling between assimilatory C uptake and respiratory loss. The study was done in the laboratory using two-month-old perennial rye-grass plants (Lolium perenne L.). After label application, the δ13C signal of respired shoot and root samples was analysed at regular time intervals using laser spectroscopy. In addition, δ13C was analysed in bulk root and shoot samples. Cold temperature (10 °C) reduced the short-term coupling between shoot and roots by delaying belowground transfer of recent assimilates and its subsequent respiratory use, as indicated by the δ13C signal of root respiration (δ13CRR). That is, the time lag from the actual shoot labelling to the first appearance of the label in 13CRR was about 1.5 times longer under cold temperature. Moreover, analysis of bulk shoot and root material revealed that plants at cold temperature invest relatively more carbon into respiration compared to growth or storage. While the whole plant C turnover increased under cold temperature, the turnover time of the labile C pool decreased, probably because less 13C is used for growth and/or storage. That is, (almost) all recent C remained in the labile pool serving respiration under these conditions. Overall, our results highlight the importance of temperature as a driver of C transport and relative C allocation within the plant–soil system.
Lena River Delta formation during the Holocene
Authors: Bolshiyanov D. , Makarov A. , Savelieva L.
Published: March 2014

Abstract. The Lena River Delta, the largest delta of the Arctic Ocean, differs from other deltas because it consists mainly of organomineral sediments, commonly called peat, that contain a huge organic carbon reservoir. The analysis of Delta sediment radiocarbon ages showed that they could not have formed as peat during floodplain bogging, but accumulated when Laptev Sea water level was high and green mosses and sedges grew and were deposited on the surface of flooded marshes. The Lena River Delta formed as organomineral masses and layered sediments accumulated during transgressive phases when sea level rose. In regressive phases, the islands composed of these sediments and other, more ancient islands were eroded. Each new sea transgression led to further accumulation of layered sediments. As a result of alternating transgressive and regressive phases the first alluvial-marine terrace formed, consisting of geological bodies of different ages. Determining the formation age of different areas of the first terrace and other marine terraces on the coast allowed the periods of increasing (8–6 Ka, 4.5–4 Ka, 2.5–1.5 Ka, 0.4–0.2 Ka) and decreasing (5 Ka, 3 Ka, 0.5 Ka) Laptev Sea levels to be distinguished in the Lena Delta area.
Estimating net anthropogenic nitrogen inputs (NANI) in the Lake Dianchi Basin of China
Authors: Gao W. , Howarth R. W. , Hong B. , Swaney D. P. , Guo H. C.
Published: March 2014

Abstract. Net anthropogenic nitrogen inputs (NANI) with components of atmospheric N deposition, synthetic N fertilizer, agricultural N fixation and N in net food and feed imports from 15 catchments in Lake Dianchi Basin were determined over an 11 year period (2000–2010). The 15 catchments range in size from 44 km2 to 316 km2 with an average of 175 km2. To reduce uncertainty from scale change methodology, results from data extracting by area-weighting and land use-weighting methods were compared. Results show that methodology for extrapolating data from county scale to watersheds has a great influence on NANI computation for catchments in the Lake Dianchi Basin, and estimates of NANI between two methods have an average difference of 30% on catchments basis while a smaller difference (15%) was observed on the whole Lake Dianchi Basin basis. The riverine N export has stronger linear relationship with NANI computed by land use-weighting method, which we believe is more reliable. Overall, nitrogen inputs assessed by the NANI approach for the Lake Dianchi Basin are 9900 kg N km−2 yr−1, ranging from 6600 to 28 000 kg N km−2 yr−1 among the 15 catchments. Synthetic N fertilizer is the largest component of NANI in most subwatersheds. On average, riverine flux of nitrogen in catchments of the Lake Dianchi Basin averages 83% of NANI, far higher than generally observed in North America and Europe. Saturated N sinks and limited capacity for denitrification in rivers may be responsible for this high percent of riverine N export. A negative intercept observed in the linear relationship between NANI and riverine N export suggests the influence of pollution control measures on N flux in small watershed. The NANI methodology should be applicable in small watersheds when sufficiently detailed data are available to estimate its components.
Contrasting roles of interception and transpiration in the hydrological cycle – Part 1: Simple Terrestrial Evaporation to Atmosphere Model
Authors: Wang-Erlandsson L. , van der Ent R. J. , Gordon L. J. , Savenije H. H. G.
Published: March 2014

Abstract. Terrestrial evaporation consists of biophysical (i.e., transpiration) and physical fluxes (i.e., interception, soil moisture, and open water). The partitioning between them depends on both climate and the land surface, and determines the time scale of evaporation. However, few land-surface models have analysed and evaluated evaporative partitioning based on land use, and no studies have examined their subsequent paths in the atmosphere. This paper constitutes the first of two companion papers that investigate the contrasting effects of interception and transpiration in the hydrological cycle. Here, we present STEAM (Simple Terrestrial Evaporation to Atmosphere Model) used to produce partitioned evaporation and analyse the characteristics of different evaporation fluxes on land. STEAM represents 19 land-use types (including irrigated land) at sub-grid level with a limited set of parameters, and includes phenology and stress functions to respond to changes in climate conditions. Using ERA-Interim reanalysis forcing for the years 1999–2008, STEAM estimates a mean global terrestrial evaporation of 73 800 km3 year−1, with a transpiration ratio of 59%. We show that the terrestrial residence time scale of transpiration (days to months) has larger inter-seasonal variation and is substantially longer than that of interception (hours). Furthermore, results from an offline land-use change experiment illustrate that land-use change may lead to significant changes in evaporative partitioning even when total evaporation remains similar. In agreement with previous research, our simulations suggest that the vegetation's ability to transpire by retaining and accessing soil moisture at greater depth is critical for sustained evaporation during the dry season. Despite a relatively simple model structure, validation shows that STEAM produces realistic evaporative partitioning and hydrological fluxes that compare well with other global estimates over different locations, seasons and land-use types. We conclude that the simulated evaporation partitioning by STEAM is useful for understanding the links between land use and water resources, and can with benefit be employed for atmospheric moisture tracking.
Results from a full coupling of the HIRHAM regional climate model and the MIKE SHE hydrological model for a Danish catchment
Authors: Larsen M. A. D. , Refsgaard J. C. , Drews M. , Butts M. B. , Jensen K. H. , Christensen J. H. , Christensen O. B.
Published: March 2014

Abstract. In recent years research on the coupling of existing regional climate models and hydrology/land surface models has emerged. A major challenge in this emerging research field is the computational interaction between the models. In this study we present results from a full two-way coupling of the HIRHAM regional climate model over a 4000 km x 2800 km domain in 11 km resolution and the combined MIKE SHE-SWET hydrology and land surface models over the 2500 km2 Skjern river catchment. A total of 26 one-year runs were performed to assess the influence of the data transfer interval (DTI) between the two models and the internal HIRHAM model variability of ten variables. In general, the coupled model simulations exhibit less accurate performance than the uncoupled simulations which is to be expected as both models prior to this study have been individually refined or calibrated to reproduce observations. Four of six output variables from HIRHAM, precipitation, relative humidity, wind speed and air temperature, showed statistically significant improvements in RMSE with a reduced DTI as evaluated in the range of 12–120 min. For these four variables the perturbation induced HIRHAM variability was shown to correspond to 47% of the RMSE improvement when using a DTI of 120 min compared to a DTI of 12 min and the variability resulted in large ranges in simulated precipitation. Also, the DTI was shown to substantially affect computation time. The MIKE SHE energy flux and discharge output variables experienced little impact from the DTI.
Challenges with couples, serodiscordance and HIV disclosure: healthcare provider perspectives on delivering safer conception services for HIV‐affected couples, South Africa
Authors: Crankshaw Tamaryn L , Mindry Deborah , Munthree Chantal , Letsoalo Thabo , Maharaj Pranitha
Published: March 2014

Introduction

Introduction Safer conception interventions should ideally involve both members of an HIV‐affected couple. With serodiscordant couples, healthcare providers will need to manage periconception risk behaviour as well tailor safer conception strategies according to available resources and the HIV status of each partner. Prior to widespread implementation of safer conception services, it is crucial to better understand provider perspectives regarding provision of care since they will be pivotal to the successful delivery of safer conception. This paper reports on findings from a qualitative study exploring the viewpoints and experiences of doctors, nurses, and lay counsellors on safer conception care in a rural and in an urban setting in Durban, South Africa.

Methods

We conducted six semistructured individual interviews per site (a total of 12 interviews) as well as a focus group discussion at each clinic site (a total of 13 additional participants). All interviews were coded in Atlas.ti using a grounded theory approach to develop codes and to identify core themes and subthemes in the data.

Results

Managing the clinical and relationship complexities related to serodiscordant couples wishing to conceive was flagged as a concern by all categories of health providers. Providers added that, in the HIV clinical setting, they often found it difficult to balance their professional priorities, to maintain the health of their clients, and to ensure that partners were not exposed to unnecessary risk, while still supporting their clients’ desires to have a child. Many providers expressed concern over issues related to disclosure of HIV status between partners, particularly when managing couples where one partner was not aware of the other's status and expressed the desire for a child. Provider experiences were that female clients most often sought out care, and it was difficult to reach the male partner to include him in the consultation.

Conclusions

Providers require support in dealing with HIV disclosure issues and in becoming more confident in dealing with couples and serodiscordance. Prior to implementing safer conception programmes, focused training is needed for healthcare professionals to address some of the ethical and relationship issues that are critical in the context of safer conception care.
Sample Treatment Strategies for Capillary Electrophoresis Analysis
Authors: Arce Lourdes , Carpio Azahara
Published: March 2014

The determination of analytes included in different types of samples by capillary electrophoresis (CE) requires their prior extraction from the sample matrix. The extraction steps are the bottleneck of many analytical processes, which should ideally involve as few operations as possible in order to minimize potential errors and shorten analysis times. In addition, there is a growing search for more environmental‐friendly approaches capable of using smaller amounts of solvents and sample sizes.

Sample treatment in CE is of great practical relevance by virtue of its inherent shortcomings, which include low sensitivity, small sample volume, and a marked influence of matrix components. The main types of coupling (on‐line, in‐line, and at‐line) are systematically dealt with and compared to manually implemented approaches in order to derive practical conclusions with a view to facilitate the use of CE for the determination of analytes present in complex samples.

The more suitable approaches for sample treatment before CE analysis are presented in this article. Although solid‐phase extraction (SPE) continues to be the most widely used extraction technique, some other clean‐up/concentration methodologies involving the use of membranes, microdialysis (MD), solid‐phase microextraction (SPME), hollow fibers (HFs), supercritical fluid extraction (SFE), and among others have proved effective alternatives for extraction, clean‐up, and sometimes preconcentration purposes.
Hydrophilic Interaction Liquid Chromatography (
HILIC
) of Small Molecules
Authors: Gama Mariana R. , Bottoli Carla B.G.
Published: March 2014

Hydrophilic interaction liquid chromatography (
HILIC
) provides an alternative approach to separation of mixtures of polar and hydrophilic compounds that are poorly resolved by reversed‐phase liquid chromatography. This separation mode involves polar stationary phases and an aqueous mobile phase, usually rich in an organic solvent such as acetonitrile. In addition to the commonly accepted mechanism of analyte liquid–liquid partitioning between the mobile phase and the water‐enriched solvent layer, which is partially immobilized onto the surface of the stationary phase, hydrogen bonding, hydrophobic interaction, and ion‐exchange interactions may also be involved.

HILIC applications for the analysis of small polar molecules can be found in pharmaceutical, medicinal, food, and agricultural chemistry. Carbohydrates, amino acids, nucleotides, polar drugs, metabolites, toxins, and other small polar or ionizable compounds are typical HILIC analytes.
The Admissibility of Laboratory Reports: TheMelendez‐Diaz,Bullcoming, andWilliamsCases
Authors: DesPortes Betty Layne
Published: March 2014

The Sixth Amendment of the United States Constitution provides seven basic rights to the accused in criminal prosecutions, including the right “to be confronted with the witnesses against him.” This right is referred to as the right to confrontation and the provision is known as “the Confrontation Clause.” In 2009, throughMelendez‐Diaz v. Massachusettsthe United States Supreme Court continued the reformation of the Confrontation Clause begun four years before inCrawford v. Washingtonwhich severed the right to confrontation from the rules of evidence concerning hearsay. InCrawford, the Court had held that the constitutional protections of the Confrontation Clause extended to all “testimonial statements.” InMelendez‐Diaz, the Court continued to define “testimonial statements,” holding that laboratory reports of forensic analysis were “testimonial” in nature. This holding meant that for the forensic reports to be admissible over defense objection, the Confrontation Clause required the presentation of the forensic analyst for in‐court testimony with the opportunity for cross‐examination. By 2012, the Supreme Court issued two more opinions inBullcoming v. New MexicoandWilliams v. Illinois, the Court addressed ancillary questions that arose, including the identity of the required live witness and extent to which the testimony of expert witnesses could rely on the work of non‐testifying analysts.
Friction Ridge Opinion Evidence afterDaubertand theNASReport
Authors: DesPortes Betty Layne
Published: March 2014

Friction ridge opinion evidence—in particular, fingerprint identification testimony—has been admitted in courts in the United States for over a century, but the milestones ofDaubertand the “NASReport” mark changes in the legal landscape concerning the admission of friction ridge opinion evidence. The seminal events of the 1993 United States Supreme Court opinion inDaubert v. Merrell Dow Pharmaceuticalsand the 2009 publication of the National Academy of Sciences Report “Strengthening Forensic Science in the United States: A Path Forward” sparked challenges to the admission of friction ridge opinion testimony and the conclusions offered by experts. In this article, the “post‐Daubert” and “post‐NAS Report” decisions concerning the admission of friction ridge opinion evidence will be discussed. As with other areas of forensic science, neitherDaubertnor theNASReport resulted in the widespread exclusion of friction ridge opinion evidence, but the legal landscape has been altered. Admissibility hearings concerning friction ridge comparison evidence, once unheard of with respect to “the gold standard” of forensic science, became more frequent and prompted legal discussions of the subjectivity of the analytical processes. Although the courts have primarily considered any “limitations” in friction ridge comparison methodologies and opinions to be properly addressed through the crucible of cross‐examination, a few courts have barred some phrasings of conclusions and representations of absolute certainty.
Anthropology: Skeleton; Estimating Juvenile Age
Authors: Cunningham Craig A.
Published: March 2014

Assessment of age from the juvenile skeleton in deceased and living individuals is a task that is frequently requested of the forensic anthropologist when an individual's biological identity is unknown. It is the only biological parameter of identity that can be assessed with any degree of accuracy from the subadult skeleton and is generally estimated by considering the well‐defined milestones that the skeleton undergoes throughout the juvenile developmental period. These developmental milestones have resulted in the formulation of literature standards that are available to aid with the assessment of age. The common methods of age estimation range from the assessment of the appearance, changing morphology and ultimate fusion of ossification centers (in dry bone assemblages and imaging studies), to the assessment of bone metrics and comparison with published standards. Each of these methods enables the formulation of an age estimate that is more accurate than can be achieved in an adult, but has limitations. This article provides a background to juvenile age assessment by discussing the growth and development of the skeleton, the common terminology associated with age estimation, and the general principles and key methods used in the establishment of skeletal age.
Hair: Animal
Authors: Tridico Silvana
Published: March 2014

The forensic examination of animal hair is a well‐established discipline and has been so for over a century. The basis of all animal hair examination is microscopy, which may enable the hair analyst to identify a hair as animal in origin, characterize the hair to a particular family or species, and conduct comparative examinations. Animal hairs bear microscopic features or characteristics that may assist in their identification. These features can be external, such as the roots and the scale pattern present along the shaft of the hair, and internal, such as the medulla. Over the last century, microscopy was the mainstay for the examination of animal hairs; however, research in relation to the transfer and persistence of animal hairs and
DNA
profiling increased data that may be obtained from these sample types. Preliminary studies conducted specifically on the transfer and persistence of animal hairs have shown that the results are comparable to the studies conducted on textile fibers. The advent of
DNA
profiling of animal hairs provided a degree of individualization that has not been possible with comparative microscopy.
Laboratory Analysis of Explosion Debris
Authors: Lancaster Sarah L. , Marshall Maurice , Oxley Jimmie C.
Published: March 2014

The forensic scientist investigating the scene of an explosion must start with the determination of whether a bomb or some mishap caused the event. Locating pieces of the explosive device or explosive residue aids in confirming the event as a bombing. The investigator is advised that proper evidence collection requires preparation before the bombing as to how to locate the most useful evidence, how to avoid contamination, how to sift explosion debris, how to conduct the chemical analyses, and what questions he must answer in a court of law. Examples from actual bombings are given and a compendium of literature references is offered.
Alkali Metals: Organometallic Chemistry
Authors: Harvey Melanie J.
Published: March 2014

Organolithium complexes, such as the organomagnesium Grignard reagents, are important reactants in organic synthesis. The similarity in structure, bonding, and reactivity of organolithium and ‐magnesium compounds exemplifies the common chemistry exhibited by representative elements that appear in the same diagonal in the periodic table. Although much debate exists over the degree of covalency within lithium–carbon bonding interactions—the presence of some covalent characters in Li–C bonds of alkyllithium compounds is widely accepted. The bonding interactions within organoalkali metal complexes of the heavier alkali metals are generally considered to be strongly electrostatic or ionic in nature. This is supported by a large collection of evidence, consisting primarily of solution
NMR
data, single‐crystal X‐ray analyses, and gas‐phase computational studies. Many of the organolithium compounds are soluble in hydrocarbons, but organometallic compounds of the heavier Group 1 metals generally require more polar media to dissolve. In general, the reactivity of the alkali metals and the reactivity of the organometallic compounds of these metals increase as the group descends. Although organoalkali metal compounds are similar to Grignard reagents, they are more reactive and are both air‐ and moisture‐sensitive and sometimes pyrophoric. In addition, organoalkali metal compounds will react as Brønsted bases with protic reagents. Specific details regarding the synthesis, reactivity, and structures of various types of organoalkali metal compounds are discussed.
Heterogeneous Catalysis by Metals
Authors: Ma Zhen , Zaera Francisco
Published: March 2014

Nowadays, over 90% of the processes in the chemical industries require the use of catalysts, and catalysis contributes directly or indirectly to approximately 35% of the world'sGDP. Most catalytic processes are heterogeneous in nature and often rely on the use of transition metal particles dispersed on high‐surface‐area supports. Herein, the basic chemical concepts behind heterogeneous metal catalysis are introduced. Examples are then provided for typical practical catalytic systems used in the generation of energy, the production of chemicals, the preparation of materials, and the cleaning of the environment. Finally, several promising new research directions related to the future development of heterogeneous metal catalysis are highlighted, in particular those associated with the designing of novel catalytic materials, the surface science of catalysis, high‐throughput catalyst testing, improved selectivities, and green chemistry.
Solids: Characterization by Powder Diffraction
Authors: Vogt Thomas
Published: March 2014

This review article covers developments in X‐ray and neutron powder diffraction with an emphasis on the complementary nature of these two condensed matter probes. After a brief overview of the basics of X‐ray and neutron scattering, examples of “mesoscopic” structure investigations (i.e., particle size, strain) are followed by a state‐of‐the‐art combined neutron, X‐ray high‐resolution, and scanning transmission electron microscopy powder diffraction study of a compositionally and structurally complex metal oxide catalyst. Neutron and X‐ray powder diffraction studies in magnetic fields are highlighted and the utility of the total scattering approach using pair‐distribution function (
PDF
) analysis within the context of “nanocrystallography” is discussed. Examples of high‐pressure crystallography using X‐ray and neutrons are given. A short outlook considers future directions in light of the emergence of new X‐ray and neutron sources and the in situ revolution in electron microscopy.
Oxygen‐evolving PhotosystemII
Authors: Pantazis Dimitrios A , Cox Nicholas , Lubitz Wolfgang , Neese Frank
Published: March 2014

PhotosystemIIis the enzyme that catalyzes the thermodynamically demanding splitting of water, yielding dioxygen, protons, and electrons, a sunlight‐driven reaction that forms the foundation of oxygenic photosynthesis. The latest results from high‐resolution crystallographic models have led to a refined view of the overall structure of the enzyme and the arrangement of the cofactors involved in light harvesting, charge separation, and electron transfer. In addition, combined efforts from protein crystallography, spectroscopy, and computational chemistry have greatly improved the understanding of the tetramanganese–calcium cluster of the oxygen‐evolving complex, the site of water oxidation. The most important features of the geometric and electronic structures of the oxygen‐evolving complex for the earlier reaction cycle intermediates are now sufficiently well understood such that connections between several structural features and spectroscopic observables can be made with confidence. Advanced spectroscopic techniques have also identified possible sites where the substrate water binds. Although the details of the actual mechanism of biological water oxidation remain elusive, experimental and theoretical studies impose an increasing number of constraints that significantly limit the number of mechanistic possibilities for O–O bond formation.
Electrets
Authors: Kaufman George K. , Gooding Diana M.
Published: March 2014

Electrets are materials that have a permanent electric field at their surface, analogous to how magnets have a permanent magnetic field. Their electric field arises from a net electrical charge or polarization. This article focuses on the former: electrets that bear a net charge. This charge can develop and dissipate in various ways; this article briefly describes advances in our understanding of how charge develops by contact electrification, corona charging, and direct charging from electrodes, and how charge dissipates by electrostatic discharge and charge decay. We also describe ways to pattern charge, including electrostatic microcontact printing, atomic force microscope‐assisted nanolithography, and new techniques for forming three‐dimensional structures. Lastly, we highlight several relatively new or still‐developing uses for electrets, including electrostatic self‐assembly for sub‐micron xerography, electrostatic generators for harvesting energy or for self‐powered sensing, sources of X‐rays that do not require high‐voltage sources of power, bioactive materials for implants, and electret‐driven chemical reactions.
Vapor Phase Metal‐Assisted Chemical Etching of Silicon
Authors: Hildreth Owen J. , Schmidt Daniel R.
Published: March 2014

This work introduces and explores vapor phase metal‐assisted chemical etching (VP‐MaCE) of silicon as a method to bypass some of the challenges found in traditional liquid phase metal‐assisted chemical etching (LP‐MaCE). Average etch rates for Ag, Au, and Pd/Au catalysts are established at 31, 70, and 96 nm/min respectively, and the relationship between etch rate and substrate temperature is examined experimentally. Just as with LP‐MaCE, 3D catalyst motion is maintained and three‐dimensional structures are fabricated with nanoparticle‐ and lithography‐patterned catalysts. VP‐MaCE produces less microporous silicon compared with LP‐MaCE and the diffusion/reduction distance of Ag+ ions is significantly reduced. This process sacrifices etch rate for increased etch uniformity and lower stiction for applications in micro‐electromechanical systems (MEMS) processing.
CdS Nanoscale Photodetectors
Authors: Deng Kaimo , Li Liang
Published: March 2014

CdS nanostructures have received much attention in recent years as building blocks for optoelectronic devices due to their unique physical and chemical properties. This progress report provides an overview of recent research about rational design of CdS nanoscale photodetectors. Three kinds of photodetectors according to the metal‐semiconductor contact types are discussed in detail: Ohmic contact, Schottky contact, and field enhanced transistor configuration. The focus is on the tuning of optical and electrical properties CdS nanostructures by element doping, composition and bandgap engineering, and heterojunction integration, along with thus modified device performances generated during these tuning processes. Latest concepts of photodetector design such as flexible, self‐powered, plasmonic, and piezophototronic photodetectors with novel properties are introduced to demonstrate the future directions of such an exciting research field.
Structural Characterization of a Composition Tolerant Bulk Heterojunction Blend
Authors: Huang Ye , Liu Xiaofeng , Wang Cheng , Rogers James T. , Su Gregory M. , Chabinyc Michael L. , Kramer Edward J. , Bazan Guillermo C.
Published: March 2014

The ratio of the donor and acceptor components in bulk heterojunction (BHJ) organic solar cells is a key parameter for achieving optimal power conversion efficiency (PCE). However, it has been recently found that a few BHJ blends have compositional tolerance and achieve high performance in a wide range of donor to acceptor ratios. For instance, the X2:PC61BM system, where X2 is a molecular donor of intermediate dimensions, exhibits a PCE of 6.6%. Its PCE is relatively insensitive to the blend ratio over the range from 7:3 to 4:6. The effect of blend ratio of X2/PC61BM on morphology and device performance is therefore systematically investigated by using the structural characterization techniques of energy‐filtered transmission energy microscopy (EF‐TEM), resonant soft X‐ray scattering (R‐SoXS) and grazing incidence wide angle X‐ray scattering (GIWAXS). Changes in blend ratio do not lead to obvious differences in morphology, as revealed by R‐SoXS and EF‐TEM. Rather, there is a smooth evolution of a connected structure with decreasing domain spacing from 8:2 to 6:4 blend ratios. Domain spacing remains constant from 6:4 to 4:6 blend ratios, which suggests the presence of continuous phases with proper domain size that may provide access for charge carriers to reach their corresponding electrodes.
Relationship between Corporate Climate Change Disclosures and Firm Factors
Authors: Eleftheriadis Iordanis M. , Anagnostopoulou Evgenia G.
Published: March 2014

As carbon regulation evolves and becomes specialized in addressing carbon reduction issues, stakeholders will demand that firms provide increased information regarding corporate climate change practices. This paper contributes to the international research that examines the relationship between environmental information disclosures and additional firm factors. To do so, we have conducted an empirical analysis of the relationship between the corporate climate change disclosure practices of firms listed in the Athens Stock Exchange and firm factors, such as size, profitability, leverage and activity sector. Our results indicate there is a significant positive relationship between size and increased corporate disclosures regarding climate change practices. However, no significant relationship is detected between profitability or leverage and corporate climate change disclosures. Copyright © 2014 John Wiley & Sons, Ltd and ERP Environment
Differential LRRK2 expression in the cortex, striatum, and substantia nigra in transgenic and nontransgenic rodents
Authors: West Andrew B. , Cowell Rita M. , Daher João P.L. , Moehle Mark S. , Hinkle Kelly M. , Melrose Heather L. , Standaert David G. , Volpicelli‐Daley Laura A.
Published: March 2014

Mutations in leucine‐rich repeat kinase 2 (LRRK2) are found in a significant proportion of late‐onset Parkinson's disease (PD) patients. Elucidating the neuroanatomical localization of LRRK2 will further define LRRK2 function and the molecular basis of PD. Here, we utilize recently characterized monoclonal antibodies to evaluate LRRK2 expression in rodent brain regions relevant to PD. In both mice and rats, LRRK2 is highly expressed in the cortex and striatum, particularly in pyramidal neurons of layer V and in medium spiny neurons within striosomes. Overall, rats have a more restricted distribution of LRRK2 compared with mice. Mice, but not rats, show high levels of LRRK2 expression in the substantia nigra pars compacta. Expression of the pathogenic LRRK2‐G2019S protein from mouse bacterial artificial chromosome (BAC) constructs closely mimics endogenous LRRK2 distribution in the mouse brain. However, LRRK2‐G2019S expression derived from human BAC constructs causes LRRK2 to be expressed in additional neuron subtypes in the rat such as striatal cholinergic interneurons and the substantia nigra pars compacta. The distribution of LRRK2 from human BAC constructs more closely resembles descriptions of LRRK2 in humans and nonhuman primates. Computational analyses of DNA regulatory elements in LRRK2 show a primate‐specific promoter sequence that does not exist in lower mammalian species. These noncoding regions may be involved in directing neuronal expression patterns. Together, these studies will aid in understanding the normal function of LRRK2 in the brain and will assist in model selection for future studies. J. Comp. Neurol. 522:2465–2480, 2014. © 2014 Wiley Periodicals, Inc.
Development of undergraduate and graduate programs in computational science
Authors: Molnár Péter , Toth David M. , Vincent‐Finley Rachel E.
Published: March 2014

There is a pressing need for a workforce with the modeling and simulation skills associated with computational science. A number of national studies have substantiated those needs with respect to the future competitiveness of USA in research and development, the innovation of new products, and the competitiveness of many industries. Creating computational science programs at academic institutions organized along disciplinary boundaries represents a challenge because aspects of computer science, mathematics, and a science or engineering domain are required parts of any program. Gaining agreement on the associated requirements, integrating the classes with those in the traditional curriculum, and obtaining the necessary support through academic and administrative reviews represent substantial challenges. Clark Atlanta University, the University of Mary Washington, and Southern University are all working on establishing undergraduate or graduate programs in computational science and have had a number of common experiences. Copyright © 2014 John Wiley & Sons, Ltd.
Age‐related differences in memory expression during infancy: Using eye‐tracking to measure relational memory in 6‐ and 12‐month‐olds
Authors: Richmond Jenny L. , Power Jessica
Published: March 2014

Relational memory, or the ability to bind components of an event into a network of linked representations, is a primary function of the hippocampus. Here we extend eye‐tracking research showing that infants are capable of forming memories for the relation between arbitrarily paired scenes and faces, by looking at age‐related changes in relational memory over the first year of life. Six‐ and 12‐month‐old infants were familiarized with pairs of faces and scenes before being tested with arrays of three familiar faces that were presented on a familiar scene. Preferential looking at the face that matches the scene is typically taken as evidence of relational memory. The results showed that while 6‐month‐old showed very early preferential looking when face/scene pairs were tested immediately, 12‐month‐old did not exhibit evidence of relational memory either immediately or after a short delay. Theoretical implications for the functional development of the hippocampus and practical implications for the use of eye tracking to measure memory during early life are discussed. © 2014 Wiley Periodicals, Inc. Dev Psychobiol 56: 1341–1351, 2014.
Combined aerobic/inspiratory muscle training vs. aerobic training in patients with chronic heart failure
Authors: Adamopoulos Stamatis , Schmid Jean‐Paul , Dendale Paul , Poerschke Daniel , Hansen Dominique , Dritsas Athanasios , Kouloubinis Alexandros , Alders Toon , Gkouziouta Aggeliki , Reyckers Ilse , Vartela Vasiliki , Plessas Nikos , Doulaptsis Costas , Saner Hugo , Laoutaris Ioannis D.
Published: March 2014

Aims

Vent‐HeFT is a multicentre randomized trial designed to investigate the potential additive benefits of inspiratory muscle training (IMT) on aerobic training (AT) in patients with chronic heart failure (CHF).

Methods and results

Forty‐three CHF patients with a mean age of 58 ± 12 years, peak oxygen consumption (peak VO2) 17.9 ± 5 mL/kg/min, and LVEF 29.5 ± 5% were randomized to an AT/IMT group (n = 21) or to an AT/SHAM group (n = 22) in a 12‐week exercise programme. AT involved 45 min of ergometer training at 70–80% of maximum heart rate, three times a week for both groups. In the AT/IMT group, IMT was performed at 60% of sustained maximal inspiratory pressure (SPImax) while in the AT/SHAM group it was performed at 10% of SPImax, using a computer biofeedback trainer for 30 min, three times a week. At baseline and at 3 months, patients were evaluated for exercise capacity, lung function, inspiratory muscle strength (PImax) and work capacity (SPImax), quality of life (QoL), LVEF and LV diameter, dyspnoea, C‐reactive protein (CRP), and NT‐proBNP. IMT resulted in a significantly higher benefit in SPImax (P = 0.02), QoL (P = 0.002), dyspnoea (P = 0.004), CRP (P = 0.03), and NT‐proBNP (P = 0.004). In both AT/IMT and AT/SHAM groups PImax (P < 0.001, P = 0.02), peak VO2 (P = 0.008, P = 0.04), and LVEF (P = 0.005, P = 0.002) improved significantly; however, without an additional benefit for either of the groups.

Conclusion

This randomized multicentre study demonstrates that IMT combined with aerobic training provides additional benefits in functional and serum biomarkers in patients with moderate CHF. These findings advocate for application of IMT in cardiac rehabilitation programmes.
Optimal integrated seismic design of structural and viscoelastic bracing‐damper systems
Authors: Castaldo Paolo , De Iuliis Massimiliano
Published: March 2014

Passive structural control techniques are generally used as seismic rehabilitation and retrofit methodologies for existing structures. A poorly explored and exciting opportunity within structural seismic control research is represented by the possibility to design new structural forms and configurations, such as slender buildings, without compromising the structural performance through an integrated design approach. In this paper, with reference to viscous dampers, an integrated seismic design procedure of the elastic stiffness resources and viscoelastic properties of a dissipative bracing‐damper system is proposed and developed to ensure a seismic design performance, within the displacement‐based seismic design, explicitly taking into account the dynamic behaviour both of the structural and control systems. The optimal integrated seismic design is defined as the combination of the variables that minimizes a suitable index, representing an optimized objective function. Numerical examples of the proposed integrated cost‐effectiveness seismic design approach both on an equivalent SDOF system and a proportionally damped MDOF integrated system are developed defining the design variables, which minimize the cost index. Validation of the effectiveness of the proposed integrated design procedure is carried out by evaluating the average displacement of the time‐history responses to seven unscaled acceleration records selected according to EC8 provisions. Copyright © 2014 John Wiley & Sons, Ltd.