bluuebunny/crossref_metadata_2025 huggingface dataset:
Distinguishing ichthyogenic turbulence from geophysical turbulence
Authors: Pujiana Kandaga , Moum James N. , Smyth William D. , Warner Sally J.
Published: April 2015

Measurements of currents and turbulence beneath a geostationary ship in the equatorial Indian Ocean during a period of weak surface forcing revealed unexpectedly strong turbulence beneath the surface mixed layer. Coincident with the turbulence was a marked reduction of the current speeds registered by shipboard Doppler current profilers, and an increase in their variability. At a mooring 1 km away, measurements of turbulence and currents showed no such anomalies. Correlation with the shipboard echo sounder measurements indicate that these nighttime anomalies were associated with fish aggregations beneath the ship. The fish created turbulence by swimming against the strong zonal current in order to remain beneath the ship, and their presence affected the Doppler speed measurements. The principal characteristics of the resultant ichthyogenic turbulence are (i) low wave number roll‐off of shear spectra in the inertial subrange relative to geophysical turbulence, (ii) Thorpe overturning scales that are small compared with the Ozmidov scale, and (iii) low mixing efficiency. These factors extend previous findings by Gregg and Horne (2009) to a very different biophysical regime and support the general conclusion that the biological contribution to mixing the ocean via turbulence is negligible.
Time domain simulations of preliminary breakdown pulses in natural lightning
Authors: Carlson B. E. , Liang C. , Bitzer P. , Christian H.
Published: April 2015

Lightning discharge is a complicated process with relevant physical scales spanning many orders of magnitude. In an effort to understand the electrodynamics of lightning and connect physical properties of the channel to observed behavior, we construct a simulation of charge and current flow on a narrow conducting channel embedded in three‐dimensional space with the time domain electric field integral equation, the method of moments, and the thin‐wire approximation. The method includes approximate treatment of resistance evolution due to lightning channel heating and the corona sheath of charge surrounding the lightning channel. Focusing our attention on preliminary breakdown in natural lightning by simulating stepwise channel extension with a simplified geometry, our simulation reproduces the broad features observed in data collected with the Huntsville Alabama Marx Meter Array. Some deviations in pulse shape details are evident, suggesting future work focusing on the detailed properties of the stepping mechanism.
Dissolution on Titan and on Earth: Toward the age of Titan's karstic landscapes
Authors: Cornet Thomas , Cordier Daniel , Bahers Tangui Le , Bourgeois Olivier , Fleurant Cyril , Mouélic Stéphane Le , Altobelli Nicolas
Published: April 2015

Titan's polar surface is dotted with hundreds of lacustrine depressions. Based on the hypothesis that they are karstic in origin, we aim at determining the efficiency of surface dissolution as a landshaping process on Titan, in a comparative planetology perspective with the Earth as reference. Our approach is based on the calculation of solutional denudation rates and allow inference of formation timescales for topographic depressions developed by chemical erosion on both planetary bodies. The model depends on the solubility of solids in liquids, the density of solids and liquids, and the average annual net rainfall rates. We compute and compare the denudation rates of pure solid organics in liquid hydrocarbons and of minerals in liquid water over Titan and Earth timescales. We then investigate the denudation rates of a superficial organic layer in liquid methane over one Titan year. At this timescale, such a layer on Titan would behave like salts or carbonates on Earth depending on its composition, which means that dissolution processes would likely occur but would be 30 times slower on Titan compared to the Earth due to the seasonality of precipitation. Assuming an average depth of 100 m for Titan's lacustrine depressions, these could have developed in a few tens of millions of years at polar latitudes higher than 70°N and S, and a few hundreds of million years at lower polar latitudes. The ages determined are consistent with the youth of the surface (<1 Gyr) and the repartition of dissolution‐related landforms on Titan.
Identifying environmental controls on the shoreline of a natural river delta
Authors: Geleynse N. , Hiatt M. , Sangireddy H. , Passalacqua P.
Published: April 2015

River deltas form where sediment‐laden water debouches into a basin. The spatial delineation of a delta is nontrivial and yet is fundamental to systematically evaluating fluxes across its surface. Here we study shoreline dynamics of the Wax Lake Delta (WLD), a naturally developing delta, downstream of the Atchafalaya River, USA. We demonstrate the ability to extract hydrodynamic and morphodynamic shorelines from time series of satellite imagery and topography data, respectively. The hydrodynamic shoreline corresponds to the traditional dry‐wet interface, whereas we introduce the concept of a morphodynamic shoreline demarcating the topset‐foreset transition of a delta to quantitatively express the degree of inundation of a delta plain. These shorelines enable us to assess environmental controls on inundation of the WLD delta plain, noting the abundance of satellite imagery, whereas time series of bathymetric data from delta plains are scarce. From the analysis of NOAA and U.S. Geological Survey environmental data, we identify the effects of river discharge, tides, wind, and vegetation on shoreline position. In particular, using Delft3D simulations and a simplified momentum balance, we highlight the nonuniform and nonlinear effect of wind on delta plain inundation. Our analyses reveal that wind, riverine discharge, and tides significantly contribute to inundation of the WLD, and hence, incorporating their interaction is essential to the accurate modeling of hydrodynamics and ecodynamics of the WLD delta plain, as well as to the dynamic shape of delta plains in general.
Uncertainty in modeled and observed climate change impacts on American Midwest hydrology
Authors: Winter Jonathan M. , Yeh Pat J.‐F. , Fu Xiaojing , Eltahir Elfatih A.B.
Published: April 2015

An important potential consequence of climate change is the modification of the water cycle in agricultural areas, such as the American Midwest. Soil moisture is the integrand of the water cycle, reflecting dynamics of precipitation, evapotranspiration, and runoff in space and time, and a key determinant of yield. Here we present projected changes in the hydrologic cycle over a representative area of the American Midwest from regional climate model experiments that sample a range of model configurations. While significant summer soil moisture drying is predicted in some ensemble members, others predict soil moisture wetting, with the sign of soil moisture response strongly influenced by choice of boundary conditions. To resolve the contradictory predictions of soil moisture across ensemble members, we assess an extensive and unique observational data set of the water budget in Illinois. No statistically significant monotonic trends are found in observed soil moisture, precipitation, streamflow, groundwater level, or 2 m air temperature over a recent 26 year period (soil moisture 25 years). Based on this analysis of model simulations and observations, we conclude that the sign of climate change impacts on the regional hydrology of the American Midwest remains uncertain.
Mercury species concentrations and fluxes in the Central Tropical Pacific Ocean
Authors: Munson Kathleen M. , Lamborg Carl H. , Swarr Gretchen J. , Saito Mak A.
Published: April 2015

The formation of the toxic and bioaccumulating monomethylmercury (MMHg) in marine systems is poorly understood, due in part to sparse data from many ocean regions. We present dissolved mercury (Hg) speciation data from 10 stations in the North and South Equatorial Pacific spanning large water mass differences and gradients in oxygen utilization. We also compare the mercury content in suspended particles from six stations and sinking particles from three stations to constrain local Hg sources and sinks. Concentrations of total Hg (THg) and methylated Hg in the surface and intermediate waters of the Equatorial and South Pacific suggest Hg cycling distinct from that of the North Pacific gyre. Maximum concentrations of 180 fM for both MMHg and dimethylmercury (DMHg) are observed in the Equatorial Pacific. South of the equator, concentrations of MMHg and DMHg are less than 100 fM. Sinking fluxes of particulate THg can reasonably explain the shape of dissolved THg profiles, but those of MMHg are too low to account for dissolved MMHg profiles. However, methylated Hg species are lower than predicted from remineralization rates based on North Pacific data, consistent with limitation of methylation in Equatorial and South Pacific waters. Full water column depth profiles were also measured for the first time in these regions. Concentrations of THg are elevated in deep waters of the North Pacific, compared to those in the intermediate and surface waters, and taper off in the South Pacific. Comparisons with previous measurements from nearby regions suggest little enrichment of THg or MMHg over the past 20 years.
Crustal thickness and Vp/Vs ratio in NW Namibia from receiver functions: Evidence for magmatic underplating due to mantle plume‐crust interaction
Authors: Heit Benjamin , Yuan Xiaohui , Weber Michael , Geissler Wolfram , Jokat Wilfried , Lushetile Bufelo , Hoffmann Karl‐Heinz
Published: April 2015

A seismological network was operated at the junction of the aseismic Walvis Ridge with the northwestern Namibian coast. We mapped crustal thickness and bulk Vp/Vs ratio by the H‐k analysis of receiver functions. In the Damara Belt, the crustal thickness is ~35 km with a Vp/Vs ratio of <1.75. The crust is ~30 km thick at the coast in the Kaoko Belt. Strong variations in crustal thickness and Vp/Vs ratios are found at the landfall of the Walvis Ridge. Here and at ~150 km northeast of the coast, the crustal thickness increases dramatically reaching 44 km and the Vp/Vs ratios are extremely high (~1.89). These anomalies are interpreted as magmatic underplating produced by the mantle plume during the breakup of Gondwana. The area affected by the plume is smaller than 300 km in diameter, possibly ruling out the existence of a large plume head under the continent during the breakup.
Fast equatorial waves propagating at the top of the Earth's core
Authors: Chulliat Arnaud , Alken Patrick , Maus Stefan
Published: April 2015

Since 2000, magnetic field variations originating in the core have been dominated by several pulses in the secular acceleration, leading to sharp geomagnetic “jerks” at the Earth's surface. Using models built from (i) Defense Meteorological Satellite Program data and (ii) Ørsted and Swarm satellites and ground observatory data, we show that a new pulse occurred in 2012.5, immediately following two pulses in 2006 and 2009. The three pulses can be decomposed into several equatorially symmetric modes propagating eastward and westward at 550 to 1100 km/yr, and one equatorially antisymmetric mode propagating eastward at 1650 km/yr. The characteristics of these modes are compatible to some extent with equatorial magnetic Rossby waves propagating within a 140 km thick layer at the top of the core with a density contrast of 50 ppm. This interpretation, if confirmed, would provide a new explanation for geomagnetic jerks and pulses based on stable stratification of the core.
Nonlinear subcyclotron resonance as a formationmechanism for gaps in banded chorus
Authors: Fu Xiangrong , Guo Zehua , Dong Chuanfei , Gary S. Peter
Published: April 2015

An interesting characteristic of magnetospheric chorus is the presence of a frequency gap at ω≃0.5Ωe, where Ωe is the electron cyclotron angular frequency. Recent chorus observations sometimes show additional gaps near 0.3Ωe and 0.6Ωe. Here we present a novel nonlinear mechanism for the formation of these gaps using Hamiltonian theory and test particle simulations in a homogeneous, magnetized, collisionless plasma. We find that an oblique whistler wave with frequency at a fraction of the electron cyclotron frequency can resonate with electrons, leading to effective energy exchange between the wave and particles.
Deformation of Indian Ocean lithosphere: Evidence for a highly nonlinear rheological law
Authors: Gordon Richard G. , Houseman Gregory A.
Published: April 2015

The width of diffuse oceanic plate boundaries is determined by the rheology of oceanic lithosphere. Here we apply thin viscous sheet models, which have been successfully applied to deformation in several continental deforming zones, to investigate the deformation of oceanic lithosphere in the diffuse oceanic plate boundaries between the India, Capricorn, and Australia Plates. We apply kinematic boundary conditions based on the current motion between these plates. We neglect buoyancy forces due to plate thinning or thickening and assume that the thin viscous sheet has the same depth‐integrated nonlinear viscosity coefficient everywhere. Our initial models have only one adjustable parameter, n, the power‐law exponent, with n = 1, 3, 10, 30, and 100. The predicted width of the deforming zone decreases with increasing n, with n ≥ 30 explaining the observations. This n value is higher than has been estimated for continental lithosphere and suggests that more of the strength of oceanic lithosphere lies in layers deforming by faulting or by dislocation glide than for continental lithosphere. To obtain a stress field that better fits the distribution and type of earthquake focal mechanisms in the diffuse oceanic plate boundary, we add a second adjustable parameter, representing the effect of slab pull stretching the oceanic plate near the Sumatra Trench. We show that an average velocity increment on this boundary segment of 5 mm a−1 (relative to the average velocity of the India and Australia Plates) fits the observed distribution of fault types better than velocities of 3.3 mm a−1 or 10 mm a−1.
M2 baroclinic tide variability modulated by the ocean circulation south of Japan
Authors: Varlamov Sergey M. , Guo Xinyu , Miyama Toru , Ichikawa Kaoru , Waseda Takuji , Miyazawa Yasumasa
Published: April 2015

We analyze a concurrent simulation result of the ocean circulation and tidal currents using a data‐assimilative ocean general circulation model covering the Western North Pacific with horizontal resolution of 1/36° to investigate possible interactions between them. Four sites of active M2 internal tide variability in open ocean (hot spots), such as Tokara Strait, Izu Ridge, Luzon Strait, and Ogasawara Ridge, are detected from both the satellite observation and the simulation. Energy cycle analysis of the simulated M2 baroclinic tide indicates two types of the hot spots: dissipation (Tokara Strait and Izu Ridge) and radiation (Luzon Strait and Ogasawara Ridge) dominant sites. Energy conversion from barotropic to baroclinic M2 tides at the hot spots is modulated considerably by the lower‐frequency changes in the density field. Modulation at the two spots (Tokara Strait and Izu Ridge) is affected by the Kuroshio path variation together with the seasonal variation of the shallow thermocline. At the other two sites, influence from changes in the relatively deep stratification through the Kuroshio intrusion into South China Sea (Luzon Strat) and mesoscale eddy activity (Ogasawara Ridge) is dominant in the modulation.
Identification of a premature stop codon mutation in the PHGDH gene in severe Neu‐Laxova syndrome—evidence for phenotypic variability
Authors: Mattos Eduardo P. , Silva André Anjos da , Magalhães José Antônio A , Leite Júlio César L. , Leistner‐Segal Sandra , Gus‐Kessler Rejane , Perez Juliano Adams , Vedolin Leonardo M. , Torreblanca‐Zanca Albertina , Lapunzina Pablo , Ruiz‐Perez Victor L. , Sanseverino Maria Teresa V.
Published: April 2015

In some cases Neu‐Laxova syndrome (NLS) is linked to serine deficiency due to mutations in the phosphoglycerate dehydrogenase (PHGDH) gene. We describe the prenatal and postnatal findings in a fetus with one of the most severe NLS phenotypes described so far, caused by a homozygous nonsense mutation of PHGDH. Serial ultrasound (US) and pre‐ and postnatal magnetic resonance imaging (MRI) evaluations were performed. Prenatally, serial US evaluations suggested symmetric growth restriction, microcephaly, hypoplasia of the cerebellar vermis, micrognathia, hydrops, shortened limbs, arthrogryposis, and talipes equinovarus. The prenatal MRI confirmed these findings prompting a diagnosis of NLS. After birth, radiological imaging did not detect any gross bone abnormalities. DNA was extracted from fetal and parental peripheral blood, all coding exons of PHGDH were PCR‐amplified and subjected to Sanger sequencing. Sequencing of PHGDH identified a homozygous premature stop codon mutation (c.1297C>T; p.Gln433*) in fetal DNA, both parents (first‐cousins) being heterozygotes. Based on previous associations of mutations in this gene with a milder NLS phenotype, as well as cases of serine deficiency, these observations lend further support to a genotype‐phenotype correlation between the degree of PHGDH inactivation and disease severity. © 2015 Wiley Periodicals, Inc.
Maternal factors associated with the occurrence of gastroschisis
Authors: Baer Rebecca J. , Chambers Christina D. , Jones Kenneth Lyons , Shew Stephen B. , MacKenzie Tippi C. , Shaw Gary M. , Jelliffe‐Pawlowski Laura L.
Published: April 2015

We sought to identify age group specific maternal risk factors for gastroschisis. Maternal characteristics and prenatal factors were compared for 1,279 live born infants with gastroschisis and 3,069,678 without. Data were obtained using the California database containing linked hospital discharge, birth certificate and death records from 1 year prior to the birth to 1 year after the birth. Backwards‐stepwise logistic regression models were used with maternal factors where initial inclusion was determined by a threshold of p < 0.10 on initial crude analyses. Due to the strong association of gastroschisis with young maternal age, models were stratified by age groups and odds ratios were calculated. These final models identified maternal infection as the only risk factor common to all age groups and a protective effect of obesity and gestational hypertension. In addition, age specific risk factors were identified. Although gestation at the time of infection was not available, a sexually transmitted disease complicating pregnancy was associated with increased risk in the less than 20 years of age grouping whereas viral infection was associated with increased risk only in the 20–24 and more than 24 years of age groupings. Urinary tract infection remained in the final logistic model for women less than 20 years. Short interpregnancy interval was not found to be a risk factor for any age group. Our findings support the need to explore maternal infection by type and gestational timing. © 2015 Wiley Periodicals, Inc.
Phenotypic modifications of patients with full chromosome aneuploidies and concurrent suspected or confirmed second diagnoses
Authors: Zarate Yuri A. , Bosanko Katherine A. , Bhoj Elizabeth , Ganetzky Rebecca , Starr Lois J. , Zackai Elaine H. , Schaefer G. Bradley
Published: April 2015

The coexistence of two or more distinct genetic conditions is known to be a rare phenomenon. Full chromosome aneuploidies can be associated with a broad variety of cytogenetic abnormalities or single gene disorders resulting in phenotypic modifications that confuse the diagnostic process. We present six patients with primary aneuploidies and a suspected or confirmed secondary genetic diagnosis or unusual birth defect. Among the cases included, we report the first patients with concurrent Down syndrome in combination with Prader‐Willi, Craniofacial Microsomia, and Stickler syndromes. We also describe only the second reported case of a neonate with Down syndrome and Marfan syndrome. In all cases, the unusual clinical presentations lead to further molecular cytogenetic studies as well as single or multi‐gene molecular evaluations. We make emphasis on the importance of entertaining the possibility of coexistent diagnoses when the phenotype is not what is expected for aneuploidies rather than attributing the unusual findings to rare or unreported associations of the primary aneuploidy. © 2015 Wiley Periodicals, Inc.
Does moderate iron deficiency protect against childhood illness? A test of the optimal iron hypothesis in Tanzania
Authors: Hadley Craig , DeCaro Jason A.
Published: April 2015

Objectives

To test the hypothesis that moderate iron deficiency among children is associated with lower likelihood of infection.

Materials and Methods

We use data from a population representative cross sectional study of 1164 Tanzanian children aged 6–59 months from the Tanzania Demographic and Health Survey. Respondents' iron levels were assessed through serum transferrin receptor (sTfR) and anemia was assessed using hemoglobin. C‐reactive protein (CRP) was used as a marker of infection.

Results

Nearly 25% of the children were categorized as normal (iron replete, non‐anemic); 45% were IDE (low iron, non‐anemic), 24% were classified as IDA (low iron, anemic), and 69 children (5.9%) were anemic but had no evidence of iron deficiency. IDE was not associated with a lower likelihood of elevated CRP compared to iron replete, non‐anemic children; 45% of normal children had elevated CRP compared to 51% of IDE children (P = 0.10). IDA, by contrast, was associated with a higher likelihood of elevated CRP (68%, P < 0.001). These results were unchanged when child, maternal, and household controls were added to a logistic regression model.

Discussion

Our results do not support the optimal iron hypothesis as conventionally formulated. The fact that we did not find an effect where some other studies have may be due to differences in study design, sample (e.g., age), or the baseline pathogenic ecology. Alternatively, it may be more fruitful to investigate iron regulation as an allostatic system that responds to infections adaptively, rather than to expect an optimal pre‐infection value. Am J Phys Anthropol 157:675–679, 2015. © 2015 Wiley Periodicals, Inc.
The impact of diabetes mellitus on outcomes of endoscopic sinus surgery: a nested case‐control study
Authors: Hajjij Amal , Mace Jess C. , Soler Zachary M. , Smith Timothy L. , Hwang Peter H.
Published: April 2015

Background

Given the immune impairment associated with diabetes mellitus (DM), its impact on chronic rhinosinusitis (CRS) is a potentially relevant concern; however, it has not been well‐studied. A single retrospective study reported worse postoperative quality of life outcomes in DM patients with CRS. Our study evaluated the effect of comorbid DM on outcomes of endoscopic sinus surgery (ESS) using a prospective study design.

Methods

Using a multicentered, prospective cohort of patients (n = 437) undergoing ESS for recalcitrant CRS, a nested case‐control comparison was performed between 20 adult DM patients (cases) and 20 non‐DM patients (controls), matched 1:1 for age and Lund‐Mackay computed tomography (CT) scores. Outcome measures included 22‐item Sinonasal Outcome Test (SNOT‐22), Rhinosinusitis Disability Index (RSDI), Patient Health Questionnaire (PHQ‐2), and Brief Smell Identification Test (BSIT).

Results

Mean follow‐up was similar between cases (mean ± standard deviation: 12.6 ± 6.0 months) and controls (12.9 ± 5.9 months; p = 0.862). All preoperative scores were statistically equivalent between DM and non‐DM cohorts. Both cohorts showed significant post‐ESS improvement in SNOT‐22 (p = 0.001) and RSDI scores (p < 0.001), and no significant change in PHQ‐2 or BSIT scores. The magnitude of score changes was statistically equivalent between the 2 cohorts for all outcome measures with no differences in postoperative score changes between insulin‐dependent DM patients and those managed by oral hypoglycemics or dietary restriction (p ≥ 0.444).

Conclusion

DM patients with CRS experience similar degrees of symptomatic benefit from ESS compared to controls. Insulin dependence does not appear to adversely affect surgical outcome but a larger cohort would better assess the effect of DM type and control on surgical outcomes in CRS.
Profibrotic transforming growth factor beta 1 and activin A are increased in nasal polyp tissue and induced in nasal polyp epithelium by cigarette smoke and Toll‐like receptor 3 ligation
Authors: Yamin Moshe , Holbrook Eric H. , Gray Stacey T. , Busaba Nicolas Y. , Lovett Brooke , Hamilos Daniel L.
Published: April 2015

Background

The mechanism of airway remodeling in chronic rhinosinusitis with nasal polyposis (CRSwNP) remains unknown. We wished to determine whether profibrotic transforming growth factor beta 1 (TGF‐β1) and activin A and their downstream signaling proteins are increased in CRSwNP and if they are regulated in epithelial cells by noxious or inflammatory stimuli.

Methods

Frozen tissue from CRSwNP patients, healthy control (HC) middle turbinates, and sinus tissue from CRS without NP (CRSsNP) patients were immunostained for TGF‐β1, activin A, and downstream signaling proteins. Primary nasal epithelial cells (PNECs) from HCs and CRSwNP patients were cultured in media, cigarette smoke extract (CSE), or double‐stranded RNA (dsRNA) (a ligand for Toll‐like receptor‐3) and examined for inflammatory and profibrotic genes using real‐time polymerase chain reaction (PCR).

Results

CRSwNP patients showed increased TGF‐β1 and activin A in the stroma, increased TGF‐β1 signaling (phosphorylated Smad2/3) in the stroma and epithelium, and increased Smad3‐dependent Snail1 in the stroma. Immunostaining for TGF‐β1, pSmad2/3, and Snail1 in CRSwNP patients was highly correlated. Immunostaining for pSmad2/3 and Snail1 was similar in CRSwNP and CRSsNP patients. Compared to HCs, PNECs from CRSwNP patients were more responsive to CSE and dsRNA in terms of TGF‐β1 and activin A and more strongly induced by dsRNA in terms of chemokines.

Conclusion

Increased TGF‐β1 and activin A and increased downstream TGF‐β1 signaling is present in CRSwNP patients, primarily in the stroma. This may contribute to features of airway remodeling previously described. PNECs from CRSwNP patients are induced to produce TGF‐β1 and activin A by CSE and dsRNA, suggesting that cigarette smoke and viral infection might also contribute to airway remodeling.
Aberrant astrocytes impair vascular reactivity in Huntington disease
Authors: Hsiao Han‐Yun , Chen Yu‐Chen , Huang Chien‐Hsiang , Chen Chiao‐Chi , Hsu Yi‐Hua , Chen Hui‐Mei , Chiu Feng‐Lan , Kuo Hung‐Chih , Chang Chen , Chern Yijuang
Published: April 2015

Objective

Huntington disease (HD) is an inherited neurodegenerative disease caused by the mutant huntingtin gene (mHTT), which harbors expanded CAG repeats. We previously reported that the brain vessel density is higher in mice and patients with HD than in controls. The present study determines whether vascular function is altered in HD and characterizes the underlying mechanism.

Methods

The brain vessel density and vascular reactivity (VR) to carbogen challenge of HD mice were monitored by 3D ΔR2‐mMRA and blood oxygenation level–dependent (BOLD)/flow‐sensitive alternating inversion recovery (FAIR) magnetic resonance imaging (MRI), respectively. The amount of vascular endothelial growth factor (VEGF)‐A and the pericyte coverage were determined by immunohistochemistry and enzyme‐linked immunosorbent assay in human and mouse brain sections, primary mouse astrocytes and pericytes, and human astrocytes derived from induced pluripotent stem cells.

Results

Expression of mHTT in astrocytes and neurons is sufficient to increase the brain vessel density in HD mice. BOLD and FAIR MRI revealed gradually impaired VR to carbogen in HD mice. Astrocytes from HD mice and patients contained more VEGF‐A, which triggers proliferation of endothelial cells and may be responsible for the augmented neurovascular changes. Moreover, an astrocytic inflammatory response, which reduces the survival of pericytes through an IκB kinase–dependent pathway, mediates the low pericyte coverage of blood vessels in HD brains.

Interpretation

Our findings suggest that the inflammation‐prone HD astrocytes provide less pericyte coverage by promoting angiogenesis and reducing the number of pericytes and that these changes can explain the inferior VR in HD mice. The resultant impaired VR might hinder cerebral hemodynamics and increase brain atrophy during HD progression. Ann Neurol 2015;78:178–192
Influence of processing conditions on polymorphic behavior, crystallinity, and morphology of electrospun poly(VInylidene fluoride) nanofibers
Authors: Baqeri Maedeh , Abolhasani Mohammad Mahdi , Mozdianfard Mohammad Reza , Guo Qipeng , Oroumei Azam , Naebe Minoo
Published: April 2015

The polymorphism and crystallinity of poly(vinylidene fluoride) (PVDF) membranes, made from electrospinning of the PVDF in pure N,N‐dimethylformamide (DMF) and DMF/acetone mixture solutions are studied. Influence of the processing and solution parameters such as flow rate, applied voltage, solvent system, and mixture ratio, on nanofiber morphology, total crystallinity, and crystal phase content of the nanofibers are investigated using scanning electron microscopy, wide‐angle X‐ray scattering, differential scanning calorimetric, and Fourier transform infrared spectroscopy. The results show that solutions of 20% w/w PVDF in two solvent systems of DMF and DMF/acetone (with volume ratios of 3/1 and 1/1) are electrospinnable; however, using DMF/acetone volume ratio of 1/3 led to blockage of the needle and spinning process was stopped. Very high fraction of β‐phase (∼79%–85%) was obtained for investigated nanofiber, while degree of crystallinity increased to 59% which is quite high due to the strong influence of electrospinning on ordering the microstructure. Interestingly, ultrafine fibers with the diameter of 12 and 15 nm were obtained in this work. Uniform and bead free nanofiber was formed when a certain amount of acetone was added in to the electrospinning solution. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42304.
Tracking the chemical surface properties of racemic thalidomide and its enantiomers using a biomimetic functional surface on a quartz crystal microbalance
Authors: Suksuwan Acharee , Lomlim Luelak , Dickert Franz L. , Suedee Roongnapa
Published: April 2015

We present details of the chemical surface properties of the molecularly imprinted polymer (MIP) on quartz crystal microbalance (QCM) for the tracking of the chiral recognition of racemic thalidomide and its (R)‐enantiomer. We investigate the assembly and specific patterns of enantiomer and racemate of thalidomide on the poly(urethane) coating consisted of the synthetic‐estrogen bisphenol A (BPA) on a QCM electrode by infrared spectroscopy and atomic force microscopy (AFM), which confirmed the surface properties of these materials. The BPA present on the surface of the coating layer revealed a positive frequency response for the racemic thalidomide that eventually appeared. This involved a negative shift of 80 Hz for a 200 µg mL−1 racemic thalidomide, and in all cases, a negative shift of 200 Hz for a 100 µg mL−1 (R)‐thalidomide. The affinity constants (Ka) for the racemate adsorbed onto the polymer layer imprinted with (R)‐thalidomide were lower than those for the (R)‐thalidomide. Also, the binding energy involved a different binding process of the chiral forms and indicated that the two enantiomers had a twofold difference in their binding energies. Thus, the advantage of the use of BPA is proven that will function as hydrogen‐bond donors in the enantioselective recognition site of the MIP. The data of functional analysis demonstrated that the biomimetic detection using molecular imprinting turn out to a study of the pharmaceutical effects of a pharmaceutically chiral compound on natural receptor functions. This approach is highly useful that highlight an enhanced understanding of the mechanism of stereochemistry required for biological controls. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42309.
Structural studies and cytotoxicity assays of “aggregation‐prone” IAPP8–16 and its non‐amyloidogenic variants suggest its important role in fibrillogenesis and cytotoxicity of human amylin
Authors: Louros Nikolaos N. , Tsiolaki Paraskevi L. , Zompra Aikaterini A. , Pappa Eleni V. , Magafa Vassiliki , Pairas George , Cordopatis Paul , Cheimonidou Christina , Trougakos Ioannis P. , Iconomidou Vassiliki A. , Hamodrakas Stavros J.
Published: April 2015

Amyloid deposits to the islets of Langerhans are responsible for the gradual loss of pancreatic β‐cells leading to type II diabetes mellitus. Human mature islet amyloid polypeptide (hIAPP), a 37‐residue pancreatic hormone, has been identified as the primary component of amyloid fibrils forming these deposits. Several individual segments along the entire sequence length of hIAPP have been nominated as regions with increased amyloidogenic potential, such as regions 8–20, 20–29, and 30–37. A smaller fragment of the 8–20 region, spanning residues 8–16 of hIAPP has been associated with the formation of early transient α‐helical dimers that promote fibrillogenesis and also as a core part of hIAPP amyloid fibrils. Utilizing our aggregation propensity prediction tools AmylPred and AmylPred2, we have identified the high aggregation propensity of the 8–16 segment of hIAPP. A peptide analog corresponding to this segment was chemically synthesized and its amyloidogenic properties were validated using electron microscopy, X‐ray fiber diffraction, ATR FT‐IR spectroscopy, and polarized microscopy. Additionally, two peptides introducing point mutations L12R and L12P, respectively, to the 8–16 segment, were chemically synthesized. Both mutations disrupt the α‐helical properties of the 8–16 region and lower its amyloidogenic potential, which was confirmed experimentally. Finally, cytotoxicity assays indicate that the 8–16 segment of hIAPP shows enhanced cytotoxicity, which is relieved by the L12R mutation but not by the L12P mutation. Our results indicate that the chameleon properties and the high aggregation propensity of the 8–16 region may significantly contribute to the formation of amyloid fibrils and the overall cytotoxic effect of hIAPP. © 2015 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 104: 196–205, 2015.
Intraventricular cerebrospinal fluid temperature analysis using MR diffusion‐weighted imaging thermometry in Parkinson's disease patients, multiple system atrophy patients, and healthy subjects
Authors: Sumida Kaoru , Sato Noriko , Ota Miho , Sakai Koji , Nippashi Yasumasa , Sone Daichi , Yokoyama Kota , Ito Kimiteru , Maikusa Norihide , Imabayashi Etsuko , Matsuda Hiroshi , Yamada Kei , Murata Miho , Kunimatsu Akira , Ohtomo Kuni
Published: April 2015

Purpose

We examined the temperature of the intraventricular cerebrospinal fluid (Tv) in patients with Parkinson's disease (PD) and those with multiple system atrophy (MSA) in comparison with healthy subjects, and we examined normal changes in this temperature with aging.

Methods

Tv was estimated by magnetic resonance (MR) diffusion‐weighted imaging (DWI) thermometry in 36 PD patients (19 males, 17 females), 34 MSA patients (17 males, 17 females), 64 age‐matched controls (27 men, 37 women), and 114 all‐age adult controls (47 men, 67 women; 28–89 years old). The volume of lateral ventricles was also estimated using FreeSurfer in all subjects. Tv and ventricular volume data were compared among the PD and MSA patients and age‐matched controls. We also evaluated the relationship between Tv and age in the 114 all‐age controls, controlling for ventricular volume. Men and women were analyzed separately.

Results

The male PD and MSA patients had significantly higher Tv values compared to the male controls, with no significant difference in ventricular volume among them. There was no significant difference in Tv between the female patients and controls. In the all‐age male controls, there was a significant negative correlation between Tv and age controlling for ventricular volume, and this was not observed in the women.

Conclusion

DWI thermometry is a useful and easy method for demonstrating an altered intracranial environment in male patients and healthy controls, but not in females. DWI thermometry can thus be used to help to explore the pathophysiology of Parkinsonian syndromes and to differentiate individuals affected by neurodegenerative disease with autonomic dysfunction from those without it.
A joint‐space numerical model of metabolic energy expenditure for human multibody dynamic system
Authors: Kim Joo H. , Roberts Dustyn
Published: April 2015

Metabolic energy expenditure (MEE) is a critical performance measure of human motion. In this study, a general joint‐space numerical model of MEE is derived by integrating the laws of thermodynamics and principles of multibody system dynamics, which can evaluate MEE without the limitations inherent in experimental measurements (phase delays, steady state and task restrictions, and limited range of motion) or muscle‐space models (complexities and indeterminacies from excessive DOFs, contacts and wrapping interactions, and reliance on in vitro parameters). Muscle energetic components are mapped to the joint space, in which the MEE model is formulated. A constrained multi‐objective optimization algorithm is established to estimate the model parameters from experimental walking data also used for initial validation. The joint‐space parameters estimated directly from active subjects provide reliable MEE estimates with a mean absolute error of 3.6 ± 3.6% relative to validation values, which can be used to evaluate MEE for complex non‐periodic tasks that may not be experimentally verifiable. This model also enables real‐time calculations of instantaneous MEE rate as a function of time for transient evaluations. Although experimental measurements may not be completely replaced by model evaluations, predicted quantities can be used as strong complements to increase reliability of the results and yield unique insights for various applications. Copyright © 2015 John Wiley & Sons, Ltd.
The diagnostic accuracy of ultrasound‐guided fine‐needle aspiration biopsy for thyroid nodules three centimeters or larger in size
Authors: Ucler Rıfkı , Usluogulları Celil Alper , Tam Abbas Ali , Ozdemir Didem , Balkan Fevzi , Yalcın Samet , Kıyak Gulten , Ersoy Pamir Eren , Guler Gulnur , Ersoy Reyhan , Cakır Bekir
Published: April 2015

Background and Purpose

Whether under ultrasonography (US) guidance or not, fine‐needle aspiration biopsy (FNAB) has some limitations, particularly in larger nodules. In this study, we aimed to evaluate the diagnostic value of US‐guided fine‐needle aspiration biopsy (US‐FNAB) in thyroid nodules equal to or larger than 3 cm.

Materials and Methods

Data of 267 patients operated for nodular goiter in the period of January 2006 and March 2012 were reviewed retrospectively. The study group (40 males, 104 females; mean age 42.3 ± 12.3, between 17 and 71) consisted of patients with nodules with a diameter of 3 cm or larger. Patients with nodules less than 3 cm in diameter were considered as the control group (27 males, 96 females; mean age 44.4 ± 11.9, between 18 and 71).

Results

For nodules smaller than 3 cm, US‐FNAB had an accuracy rate of 60% and a false negativity rate of 21.9%. In nodules equal to or larger than 3 cm, the accuracy rate of US‐FNAB was 80%, with a false negativity rate of 6.7%. Malignancy was observed in 16% of the study group and 42.3% of the control group.

Conclusion

This study showed that increased nodule diameter is not associated with limitations in the diagnostic value of US‐FNAB. We also found that the malignancy rate was smaller for larger nodules. This finding reflects the importance of accurate and rational diagnostic work‐up and clinical management for detecting malignancy and surgical decision‐making. Diagn. Cytopathol. 2015;43:622–628. © 2015 Wiley Periodicals, Inc.
Hippocampal neuron populations are reduced in vervet monkeys with fetal alcohol exposure
Authors: Burke Mark W. , Ptito Maurice , Ervin Frank R. , Palmour Roberta M.
Published: April 2015

Prenatal exposure to beverage alcohol is a major cause of mild mental retardation and developmental delay. In nonendangered alcohol‐preferring vervet monkeys, we modeled the most common nondysmorphic form of fetal alcohol syndrome disorder with voluntary drinking during the third trimester of pregnancy. Here, we report significant numerical reductions in the principal hippocampal neurons of fetal alcohol‐exposed (FAE) offspring, as compared to age‐matched, similarly housed conspecifics with isocaloric sucrose exposure. These deficits, particularly marked in CA1 and CA3, are present neonatally and persist through infancy (5 months) and juvenile (2 years) stages. Although the volumes of hippocampal subdivisions in FAE animals are not atypical at birth, by age 2, they are only 65–70% of those estimated in age‐matched controls. These data suggest that moderate, naturalistic alcohol consumption during late pregnancy results in a stable loss of hippocampal neurons and a progressive reduction of hippocampal volume. © 2015 The Authors. Developmental Psychobiology Published by Wiley Periodicals, Inc. Dev Psychobiol 57:470𠄃485, 2015.
UV absorption‐based inverse modeling of protein chromatography
Authors: Hahn Tobias , Baumann Pascal , Huuk Thiemo , Heuveline Vincent , Hubbuch Jürgen
Published: April 2015

UV absorbance measurements play an important role in bioprocess development. Yield and purity are often evaluated in terms of peak percentages in analytical SEC or ion‐exchange chromatography. Also, industrial chromatography steps are usually controlled based on UV data with pooling decisions according to absorbance thresholds. Model‐based process development would make elaborate screening experiments redundant, once the model has been calibrated to the specific process step. So far, absorbance measurements could not be used directly for modeling chromatography steps as the commonly applied models rely on mass or molar concentration. This study presents mechanistic modeling of an industrially relevant chromatography setting without any knowledge of the feed composition. The model equations were rewritten to employ boundary conditions in UV absorbance units, the absorption coefficients were shifted into the isotherm, and standard parameter estimation procedures could be applied. An anion‐exchange chromatography case study of a target protein expressed in Escherichia coli and 11 lumped impurity peaks demonstrated practical applicability. The target protein concentration in the feed material was estimated from chromatograms. Using this method, initially unknown feed concentrations can be determined a posteriori for ion‐exchange and multimodal chromatography from single‐component absorbance curves.
Adult‐born dentate neurons are recruited in both spatial memory encoding and retrieval
Authors: Tronel Sophie , Charrier Vanessa , Sage Cyrille , Maitre Marlene , Leste‐Lasserre Thierry , Abrous Djoher N.
Published: April 2015

Adult neurogenesis occurs in the dentate gyrus (DG) of the hippocampus, which is a key structure in learning and memory. Adult‐generated granule cells have been shown to play a role in spatial memory processes such as acquisition or retrieval, in particular during an immature stage when they exhibit a period of increased plasticity. Here, we demonstrate that immature and mature neurons born in the DG of adult rats are similarly activated in spatial memory processes. By imaging the activation of these two different neuron generations in the same rat and by using the immediate early gene Zif268, we show that these neurons are involved in both spatial memory acquisition and retrieval. These results demonstrate that adult‐generated granule cells are involved in memory beyond their immaturity stage. © 2015 Wiley Periodicals, Inc.
Air emissions associated with decommissioning California's offshore oil and gas platforms
Authors: Cantle Peter , Bernstein Brock
Published: April 2015

The 27 oil and gas platforms offshore southern California are nearing the end of their productive lives and will be decommissioned in the near future. Many are in deep water and are correspondingly large, with the largest, Harmony, in 1200 feet of water and weighing approximately 43 000 tons. Nearly 30% of California's platforms are in water depths that exceed those of any previous decommissioning project anywhere in the world. Decommissioning will involve the operation of diesel-powered heavy equipment for long periods in virtually all phases of the operation (e.g, at the platform, in transit to and from the platform, in port, at offloading, salvage, and recycling facilities) in a region where air quality is a crucial concern for state, federal, and local regulatory agencies, as well as the public. To support future decision making about the choice between decommissioning options, we consider potential air emissions generated under complete and partial (removal to 85 feet below water line) removal options. We describe major emissions categories, and the environmental and human health issues associated with each, and examine how the regulatory system would operate in specific projects. We then describe methods to estimate emissions for a worst-case example involving the largest platform, Harmony. We estimate that complete versus partial removal of Harmony would result, respectively, in 600 or 89 tons of NOx, 50 or 7 tons of carbon monoxide, 29 400 or 4400 tons of CO2, 21 or 3 tons of PM10, and 20 or 3 tons of PM2.5. Complete removal of Harmony's jacket and topsides creates approximately 6.75 times more air pollution than partial removal down to 85 feet below the sea surface. We discuss how the Harmony estimate can be used as a baseline to roughly estimate emissions from decommissioning other platforms, using expected time on station for the major categories of decommissioning equipment. Integr Environ Assess Manag 2015;X:000–000. © 2015 SETAC

Key Points

The majority of air pollution emissions from platform decommissioning will result from diesel engine combustion during the removal and salvage process. Total air pollution emissions during partial or complete removal varies based on the number of days diesel engines are used. Using the interactive decision model PLATFORM, complete removal of the largest oil platform off the California coast, ExxonMobil's Harmony, would result in an estimated 6.75 times more air pollution than partial removal 85 ft below the sea surface. Complete versus partial removal of Harmony would result, respectively, in 600 or 89 tons of NOx, 50 or 7 tons of carbon monoxide, 29,400 or 4,400 tons of CO2, 21 or 3 tons of PM10, and 20 or 3 tons of PM2.5.