bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of 940 MHz EMF on luciferase solution: Structure, function, and dielectric studies
Authors: Sefidbakht Yahya , Hosseinkhani Saman , Mortazavi Mojtaba , Tavakkolnia Iman , Khellat Mohammad R. , Shakiba‐Herfeh Mahdi , Saviz Mehrdad , Faraji‐Dana Reza , Saboury Ali A. , Sheibani Nader , Moosavi‐Movahedi Ali A.
Published: April 2013

We designed a rectangular waveguide exposure system to study the effects of mobile phone frequency (940 MHz) electromagnetic fields (EMF) on luciferase structure and activity. The luciferase activity of exposed samples was significantly higher than that of unexposed samples. Dynamic light scattering of the exposed samples showed smaller hydrodynamic radii compared to unexposed samples (20 nm vs. 47 nm ± 5%). The exposed samples also showed less tendency to form aggregates, monitored by turbidity measurements at λ = 360 nm. A microwave dielectric measurement was performed to study the hydration properties of luciferase solutions with a precision network analyzer over frequency ranges from 0.2 to 20 GHz before and after exposure. The change in the dielectric properties of the exposed luciferase solution was related to the disaggregation potency of the applied field. Together, our results suggested that direct interactions with luciferase molecules and its dipole moment were responsible for the reduced aggregation and enhanced luciferase activity upon exposure to the EMF. Bioelectromagnetics. 34:489–498. © 2013 Wiley Periodicals, Inc.
Thermal quenching of luminescence of LiSr4(BO3)3:Eu2+ orange‐emitting phosphor
Authors: Zhang Xinguo , Zhou Liya , Gong Menglian
Published: April 2013

An orange‐emitting phosphor, Eu2+‐activated LiSr4(BO3)3, was synthesized using the conventional solid‐state reaction. The photoluminescence excitation and emission spectra, and temperature dependence of the luminescence intensity of the phosphor were investigated. The results showed that LiSr4(BO3)3:Eu2+ could be efficiently excited by incident light of 250–450 nm, and emits a strong orange light. With increasing temperature, the emission bands of LiSr4(BO3)3:Eu2+ show an abnormal blue‐shift with broadening bandwidth and decreasing emission intensity. Copyright © 2013 John Wiley & Sons, Ltd.
Evaluation of lophine derivatives as L‐012 (luminol analog)‐dependent chemiluminescence enhancers for measuring horseradish peroxidase and H2O2
Authors: Ichibangase T. , Ohba Y. , Kishikawa N. , Nakashima K. , Kuroda N.
Published: April 2013

8‐Amino‐5‐chloro‐7‐phenylpyrido[3,4‐d]pyridazine‐1,4(2H,3H)dione (L‐012) was recently synthesized as a new chemiluminescence (CL) probe; the light intensity and the sensitivity of L‐012 are higher than those of other CL probes such as luminol. Previously, our group developed four lophine‐based CL enhancers of the horseradish peroxidase (HRP)‐catalyzed CL oxidation of luminol, namely 2‐(4‐hydroxyphenyl)‐4,5‐diphenylimidazole (HDI), 2‐(4‐hydroxyphenyl)‐4,5‐di(2‐pyridyl)imidazole (HPI), 4‐(4,5‐diphenyl‐1H‐imidazol‐2‐yl)phenylboronic acid (DPA), and 4‐[4,5‐di(2‐pyridyl)‐1H‐imidazol‐2‐yl]phenylboronic acid (DPPA), and showed that DPPA was suitable for the photographic detection of HRP. In this study, we replaced luminol with L‐012 and evaluated these as L‐012‐dependent CL enhancers. In addition, to detect HRP and/or H2O2 with higher sensitivity, each detection condition for the L‐012–HRP–H2O2 enhanced CL was optimized. All the derivatives enhanced the L‐012‐dependent CL as well as luminol CL; HPI generated the highest enhanced luminescence. Under optimized conditions for HRP detection, the detection limit of HRP was 0.08 fmol. By contrast, the detection limit of HRP with the enhanced L‐012‐dependent CL using 4‐iodophenol, which is a common enhancer of luminol CL, was 1.1 fmol. With regard to H2O2 detection, the detection limits for enhanced CL with HPI and 4‐iodophenol were 0.29 and 1.5 pmol, respectively. Therefore, it is demonstrated that HPI is the most superior L‐012‐dependent CL enhancer. Copyright © 2013 John Wiley & Sons, Ltd. Copyright © 2013 John Wiley & Sons, Ltd.
Robust stability analysis inspired by classical statistical principles
Authors: Silva Nilton , Bispo Heleno , Brito Romildo , Manzi João
Published: April 2013

An analysis was made of robust stability by estimating the robust confidence region for the roots of the characteristic Equation of a process, which uses a typical PID controller with auto‐tuning. From standard statistical concepts, considerations on the statistical distance associated with the chi‐square distribution were taken into account when establishing the methodology, which enabled the region of robust stability to be found. The results show the robust stability region for all eigenvalues of characteristic equation, thus demonstrating the ability of the procedure. The region of stability can be updated online, thus enabling the stability of the system to be continuously evaluated, with little computational effort.
Outcomes in stage I testicular seminoma: A population‐based study of 9193 patients
Authors: Beard Clair J. , Travis Lois B. , Chen Ming‐Hui , Arvold Nils D. , Nguyen Paul L. , Martin Neil E. , Kuban Deborah A. , Ng Andrea K. , Hoffman Karen E.
Published: April 2013

BACKGROUND

Few studies have quantified temporal patterns of cause‐specific mortality in contemporary cohorts of men with early‐stage seminoma. Given that several management strategies can be applied in these patients, each resulting in excellent long‐term survival, it is important to evaluate associated long‐term sequelae. In particular, data describing long‐term risks of cardiovascular disease (CVD) are conflicting.

METHODS

We identified 9193 men diagnosed with stage I seminoma (ages 15‐70 years) in the population‐based SEER registries (1973‐2001). We calculated survival estimates, standardized mortality ratios (SMRs), and adjusted hazard rates (AHRs).

RESULTS

During 121,037 person‐years of follow‐up (median, 12.3 years), 915 deaths (SMR, 1.23; 95% CI, 1.16‐1.32) were reported, with significant excesses for suicide (n = 39; SMR, 1.45; 95% CI, 1.06‐1.98), infection (n = 58; SMR, 2.32; 95% CI, 1.80‐3.00), and second malignant neoplasms (SMNs; n = 291; SMR, 1.81; 95% CI, 1.61‐2.03), but not CVD (n = 201; SMR, 0.91; 95% CI, 0.80‐1.05). After radiotherapy (78% patients), CVD deaths were not increased (n = 158; SMR, 0.89; 95% CI, 0.76‐1.04), in contrast to SMN deaths (n = 246; SMR, 1.89; 95% CI, 1.67‐2.14). SMN mortality was higher among patients administered radiotherapy than among those not given radiotherapy (AHR, 1.36; 95% CI, 0.99‐1.88;P = .059), with a cumulative 15‐year risk of 2.64% (95% CI, 2.19‐3.16). Suicide, although rare, accounted for 1 in 230 deaths.

CONCLUSIONS

Modern radiotherapy as applied in this large population‐based study is not associated with excess CVD mortality. Although increased all‐cause mortality exists, cumulative SMN risk is considerably smaller than reported in historical series, but additional follow‐up will be required to characterize long‐term trends. The increased risk of suicide, previously unreported in men with stage I seminoma, requires confirmation.Cancer2013;119:2771–2777. ©2013 American Cancer Society.
Posterior reversible encephalopathy syndrome in neuroblastoma patients receiving anti‐GD2 3F8 monoclonal antibody
Authors: Kushner Brian H. , Modak Shakeel , Basu Ellen M. , Roberts Stephen S. , Kramer Kim , Cheung Nai‐Kong V.
Published: April 2013

BACKGROUND

Posterior reversible encephalopathy syndrome (PRES) comprises clinical and radiologic findings with rapid onset and potentially dire consequences. Patients experience hypertension, seizures, headache, visual disturbance, and/or altered mentation. Magnetic resonance imaging reveals edematous changes in the brain (especially in the parietal and occipital lobes). In this report, the authors describe PRES associated with antidisialoganglioside (anti‐GD2) monoclonal antibody (MoAb) immunotherapy, which is now standard for high‐risk neuroblastoma but has not previously been implicated in PRES.

METHODS

Successive clinical trials using the anti‐GD2 MoAb 3F8 (a murine immunoglobulin 3 MoAb specific for GD2) for patients with neuroblastoma involved multiple cycles of standard‐dose 3F8 (SD‐3F8) (20 mg/m2 daily for 5 days per cycle) or 2 cycles of high‐dose 3F8 (HD‐3F8) (80 mg/m2 daily for 5 days per cycle) followed by cycles of SD‐3F8.

RESULTS

PRES was diagnosed in 5 of 215 patients (2.3%), including 3 of 160 (1.9%) who received SD‐3F8 and 2 of 55 (3.6%) who received HD‐3F8 (P = .6). All 5 patients had a rapid return to clinical‐radiologic baseline. PRES occurred in 3 of 26 patients (11.5%) whose prior treatment included external‐beam radiotherapy to the brain (2 of 6 patients status‐post total body irradiation and 1 of 20 patients status‐post craniospinal irradiation) compared with 2 of 189 patients (1.1%) who had not received prior brain irradiation (P = .01). Hypertension, which is strongly linked to PRES, reached grade 3 toxicity in 12 of 215 patients (5.6%), including the 5 patients with PRES and 7 patients without PRES.

CONCLUSIONS

Patients who receive anti‐GD2 MoAb immunotherapy should be closely monitored for, and undergo urgent treatment or evaluation of, symptoms that may herald PRES (eg, hypertension or headaches). Prior brain irradiation may be a predisposing factor for PRES with this immunotherapy. Cancer 2013;119:2789–2795. © 2013 American Cancer Society.
Syntheses of New Carbanucleosides by Pericyclic Reactions
Authors: Scagnelli Luca , Memeo Misal Giuseppe , Carosso Serena , Bovio Bruna , Quadrelli Paolo
Published: April 2013

The synthesis of heterobase‐functionalized cyclopentene derivatives as valuable substrate for the introduction of suitable substituents through pericyclic reactions is reported. The structures of ene and 1,3‐dipolar adducts are discussed, and the primary antiviral activities of some adenine derivatives are reported.
Technical and economic analysis of renewable energy powered stand‐alone pole street lights for remote area
Authors: Wadi Abbas Al-Fatlawi Ali , Abdul-Hakim Saidur R. , Ward T. A. , Rahim Nasruddin A.
Published: April 2013

Several different stand‐alone pole street lighting (SPSL) models, using a light emitting diode (LED) lamp, were tested over a 1‐year period on Penang Island in northern Malaysia. The models were powered by lead–lead dioxide batteries, autonomously recharged by a renewable energy power source (RES): either a photovoltaic (PV) generator or an integrated PV/Wind‐turbine generator system. The technical requirements and economic impact (capital and operating costs) of these two configurations are analyzed and compared. Additionally, some of these configurations were programmed with an energy load savings scheme. The impact of operating with this scheme was compared to operations performed at full load. Results of this comparative analysis revealed that the most efficient system for the test environment was the PV generator operating with the energy savings scheme. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 283–289, 2014
Effect of ozone and ozone/persulfate processes on biodegradable and soluble characteristics of semiaerobic stabilized leachate
Authors: Abu Amr Salem S. , Aziz Hamidi Abdul , Adlan Mohd Nordin , Alkasseh Jaber M.A.
Published: April 2013

This study investigated the effects of O3 and O3/S2O82− in the advanced oxidation process (AOPs) on the biodegradable and soluble characteristics of semiaerobic stabilized solid waste leachate. The biodegradability (BOD5/COD) ratio improved from 0.034 to 0.05 and 0.29 following O3 and O3/ S2O82−, respectively. Fractions of biodegradable COD(bi) (24%), nonbiodegradable COD(ubi) (76%), soluble COD(s) (59%), biodegradable soluble COD(bsi) (38%), nonbiodegradable soluble COD(ubsi) (62%), and particulate COD (PCOD) (41%) in stabilized leachate were also investigated. The fraction of COD (bi) increased to 28 and 39% after applying O3 and O3/ S2O82− in AOPs, respectively. COD(S) increased to 65 after O3 and to 72% after O3/AOPs, whereas COD (bsi) increased to 38 and 55% after O3 and O3/AOPs, respectively. The removal efficiency of total COD was obtained at 15 after O3 alone and improved to 72% following ozone‐based AOPs, whereas PCOD reduced from 41 to 35 after O3 and 28% after ozone‐based AOPs. Ozone/Prsulfate is an efficient method for degradation of stabilized leachate, enhanced biodegradability and improved biodegradable and soluble characteristics of stabilized leachate. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 184–191, 2014
Purging Disorder: A Comparison to Established Eating Disorders with Purging Behaviour
Authors: Koch Sonja , Quadflieg Norbert , Fichter Manfred
Published: April 2013

This study is part of the larger Christina Barz Study, and it compared consecutively admitted patients with purging disorder (PurD; N = 225) with consecutively admitted patients with anorexia nervosa binge eating/purging subtype (AN‐bp; N = 503) and bulimia nervosa purging subtype (BN‐p; N = 756). Participants answered self‐rating questionnaires on admission, at the end of inpatient treatment, and in a 5‐year follow‐up. Patients with PurD reported lower severity of general psychopathology than patients with AN‐bp and lower severity of eating disorder symptoms than patients with AN‐bp and BN‐p on admission. Eating disorder symptoms of patients with PurD improved less during the course than of the comparison groups. Diagnostic perseverance was stronger in the PurD group than for patients with AN‐bp; mortality was higher than for patients with BN‐p. Predictors for better outcome differed for the groups. Our results provide new data about the long‐term course of patients with PurD and indicate clinical relevance of the disorder. Copyright © 2013 John Wiley & Sons, Ltd and Eating Disorders Association.
The polychaete worm Nereis diversicolor increases mercury lability and methylation in intertidal mudflats
Authors: Sizmur Tom , Canário João , Edmonds Samuel , Godfrey Adam , O'Driscoll Nelson J.
Published: April 2013

The polychaete worm Nereis diversicolor engineers its environment by creating oxygenated burrows in anoxic intertidal sediments. The authors carried out a laboratory microcosm experiment to test the impact of polychaete burrowing and feeding activity on the lability and methylation of mercury in sediments from the Bay of Fundy, Canada. The concentration of labile inorganic mercury and methylmercury in burrow walls was elevated compared to worm-free sediments. Mucus secretions and organic detritus in worm burrows increased labile mercury concentrations. Worms decreased sulfide concentrations, which increased Hg bioavailability to sulfate-reducing bacteria and increased methylmercury concentrations in burrow linings. Because the walls of polychaete burrows have a greater interaction with organisms, and the overlying water, the concentrations of mercury and methylmercury they contain is more toxicologically relevant to the base of a coastal food web than bulk samples. The authors recommend that researchers examining Hg in marine environments account for sediment dwelling invertebrate activity to more fully assess mercury bioavailability. Environ Toxicol Chem 2013;32:1888–1895. © 2013 SETAC
Water Evolution in Direct Methanol Fuel Cell Cathodes Studied by Synchrotron X‐Ray Radiography
Authors: Schröder A. , Wippermann K. , Arlt T. , Sanders T. , Baumhöfer T. , Markötter H. , Mergel J. , Lehnert W. , Stolten D. , Manke I. , Banhart J.
Published: April 2013

Water evolution, distribution, and removal in the cathodes of a running direct methanol fuel cell were investigated by means of synchrotron X‐ray radiography. Radiographs with a spatial resolution of around 5 μm were taken every 5 s. Special cell designs allowing for through‐plane and in‐plane viewing were developed, featuring two mirror‐symmetrical flow field structures consisting of one channel with the through‐plane design. Evolution and discharge of water droplets and the occurrence of water accumulations in selected regions of the channels were investigated. These measurements revealed a nonuniform distribution of water in the channels. Both irregular and periodic formation of water droplets were observed. In‐plane measurements revealed, that the droplets evolve between adjacent carbon fiber bundles of the gas diffusion layer. The water distribution within the channel cross‐section fits very well to the pressure difference between cathode channel inlet and outlet. The quick discharge of water droplets causes sudden decreases of the pressure difference up to 4.5 mbar.
Three‐dimensional nuclear telomere architecture changes during endometrial carcinoma development
Authors: Danescu Adrian , Herrero Gonzalez Sandra , Di Cristofano Antonio , Mai Sabine , Hombach‐Klonisch Sabine
Published: April 2013

Endometrioid or type‐I endometrial carcinoma (EC) develops from hyperproliferative glandular pathologies. Inactivation of the tumor suppressor gene PTEN is frequently associated with type‐I EC. Using a previously characterized Pten heterozygous (Pten+/‐) mouse model, this study investigates the three‐dimensional (3D) telomere profiles during progression from hyperplastic lesions to EC to test the hypothesis that altered 3D telomere profiles can be detected prior to Pten loss in early hyperproliferative lesions. We used immunohistochemistry and 3D‐telomere fluorescent in‐situ hybridization to investigate Pten expression, telomere length and signal distribution, average number and spatial distribution of telomeres and formation of telomere aggregates in uterine glandular epithelial cells from wildtype and Pten+/‐ mice. Pten showed nuclear and cytoplasmic localization in WT, predominantly cytoplasmic staining in simple hyperplasia (SH) and was markedly reduced in atypical hyperplasia (AH). Telomere length in glandular epithelial cells does not shorten with age. The average number of telomeres per nucleus was not different in WT and Pten+/‐ mice indicating the lack of substantial numeric chromosome aberrations during EC development. We observed telomere aggregates in lesions of AH and EC. SH lesions in Pten+/‐ mice differed from normal glandular epithelium by an increased relative number of shorter telomeres and by a telomere signal distribution indicative of a heterogeneous cell population. Our study revealed that alterations in the nuclear 3D telomere architecture are present in early proliferative lesions of mouse uterine tissues indicative of EC development. The changes in telomere length distribution and nuclear signal distribution precede the loss of Pten. © 2013 Wiley Periodicals, Inc.
Acoustic emissions document stress changes over many seismic cycles in stick‐slip experiments
Authors: W. Goebel T. H. , Schorlemmer D. , Becker T. W. , Dresen G. , Sammis C. G.
Published: April 2013

The statistics of large earthquakes commonly involve large uncertainties due to the lack of long‐term, robust earthquake recordings. Small‐scale seismic events are abundant and can be used to examine variations in fault structure and stress. We report on the connection between stress and microseismic event statistics prior to the possibly smallest earthquakes: those generated in the laboratory. We investigate variations in seismic b value of acoustic emission events during the stress buildup and release on laboratory‐created fault zones. We show that b values mirror periodic stress changes that occur during series of stick‐slip events, and are correlated with stress over many seismic cycles. Moreover, the amount of b value increase associated with slip events indicates the extent of the corresponding stress drop. Consequently, b value variations can be used to approximate the stress state on a fault: a possible tool for the advancement of time‐dependent seismic hazard assessment.
Identification of hepatic microvascular adhesion‐related genes of human colon cancer cells using random homozygous gene perturbation
Authors: Márquez Joana , Kohli Manu , Arteta Beatriz , Chang Shaojing , Li Wu‐Bo , Goldblatt Michael , Vidal‐Vanaclocha Fernando
Published: April 2013

Random homozygous gene perturbation (RHGP), in combination with liver sinusoidal endothelial cell (LSEC) adhesion screening of clonal colon cancer cells with perturbed genes, was used to identify genes contributing to the hepatic microvascular adhesion of colon cancer cells. Plasmid vector encoding transactivator and gene search vector were transfected into HT‐29 human colorectal cancer cells to create a HT‐29 RHGP cell library; the adhesion of these library cells to primary cultured mouse LSEC significantly decreased in the presence of RSL1 ligand (inducer), indicating that most of the genes contributing to HT‐29 adhesion to LSEC were altered. Next, HT‐29 RHGP cell library fractions with upregulated or silenced LSEC adhesion‐related genes were isolated. Around 160 clones having altered expression in LSEC adhesion‐related genes were obtained, and nine relevant protein‐coding genes were identified. Some were proadhesive genes detected because of their overexpression in adherent HT‐29 cells (DGCR8 and EFEMP1 genes) and their silenced status in nonadherent HT‐29 cells (DGKE, DPY19L1, KIAA0753, PVR and USP11 genes). Others were antiadhesive genes detected because of their overexpression in nonadherent HT‐29 cells (ITPKC gene) and their silenced status in adherent HT‐29 cells (PPP6R2 gene). Silencing of PVR, DGCR8 and EFEMP1 genes decreased adhesion to LSEC and hepatic microvascular retention of HT‐29 cells. The results conclude that RHGP was a valuable strategy for the discovery of mechanisms regulating microvascular adhesion of circulating colon cancer cells before hepatic metastasis formation. Identified genes may contribute to understand the metastatic process of colon cancer and to discovering molecular targets for hepatic metastasis therapeutics.
Integration of microfluidic chip with biomimetic hydrogel for 3D controlling and monitoring of cell alignment and migration
Authors: Lee Kwang Ho , Lee Ki Hwa , Lee Jeonghoon , Choi Hyuk , Lee Donghee , Park Yongdoo , Lee Sang‐Hoon
Published: April 2013

A biomimetic hydrogel was integrated into microfluidic chips to monitor glioma cell alignment and migration. The extracellular matrix‐based biomimetic hydrogel was remodeled by matrix metalloprotease (MMP) secreted by glioma cells and the hydrogel could thus be used to assess cellular behavior. Both static and dynamic cell growth conditions (flow rate of 0.1 mL/h) were used. Cell culture medium with and without vascular endothelial growth factor (VEGF), insensitive VEGF and tissue inhibitor of metalloproteinases (TIMP) were employed to monitor cell behavior. A concentration gradient formed in the hydrogel resulted in differences in cell behavior. Glioma cell viability in the microchannel was 75–85%. Cells in the VEGF‐loaded microchannels spread extensively, degrading the MMP‐sensitive hydrogel, and achieved cell sizes almost fivefold larger than seen in the control medium. Our integrated system can be used as a model for the study of cellular behavior in a controlled microenvironment generated by fluidic conditions in a biomimetic matrix. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 1164–1172, 2014.
Suppression of autophagy by FIP200 deletion leads to osteopenia in mice through the inhibition of osteoblast terminal differentiation
Authors: Liu Fei , Fang Fang , Yuan Hebao , Yang Dongye , Chen Yongqiang , Williams Linford , Goldstein Steven A , Krebsbach Paul H , Guan Jun-Lin
Published: April 2013

Autophagy is a conserved lysosomal degradation process that has important roles in both normal human physiology and disease. However, the function of autophagy in bone homeostasis is not well understood. Here, we report that autophagy is activated during osteoblast differentiation. Ablation of focal adhesion kinase family interacting protein of 200 kD (FIP200), an essential component of mammalian autophagy, led to multiple autophagic defects in osteoblasts including aberrantly increased p62 expression, deficient LC3-II conversion, defective autophagy flux, absence of GFP-LC3 puncta in FIP200-null osteoblasts expressing transgenic GFP-LC3, and absence of autophagosome-like structures by electron microscope examination. Osteoblast-specific deletion of FIP200 led to osteopenia in mice. Histomorphometric analysis revealed that the osteopenia was the result of cell-autonomous effects of FIP200 deletion on osteoblasts. FIP200 deletion led to defective osteoblast terminal differentiation in both primary bone marrow and calvarial osteoblasts in vitro. Interestingly, both proliferation and differentiation were not adversely affected by FIP200 deletion in early cultures. However, FIP200 deletion led to defective osteoblast nodule formation after initial proliferation and differentiation. Furthermore, treatment with autophagy inhibitors recapitulated the effects of FIP200 deletion on osteoblast differentiation. Taken together, these data identify FIP200 as an important regulator of bone development and reveal a novel role of autophagy in osteoblast function through its positive role in supporting osteoblast nodule formation and differentiation. © 2013 American Society for Bone and Mineral Research.
Switching between seismic and seismo‐acoustic harmonic tremor simulated in the laboratory: Insights into the role of open degassing channels and magma viscosity
Authors: Lyons John J. , Ichihara Mie , Kurokawa Aika , Lees Jonathan M.
Published: April 2013

Switching between seismic‐only harmonic tremor (SHT) and seismo‐acoustic harmonic tremor (SAHT) has been reported at few volcanoes worldwide, but its occurrence may indicate important changes in shallow conduit conditions. Switching was simulated in a laboratory experiment in which harmonic signals were produced with a flow‐driven valve and compressed air. The harmonic signals were passed through a tank of shear‐thinning viscoelastic fluid, and the resulting signals were recorded. At high fluid stiffness, a stable, open conduit was produced, and the harmonic signals generated within the experimental apparatus were efficiently transmitted into the atmosphere. At lower fluid stiffness, bubbling dominated the activity, stable pathways were not generated in the fluid, and HT was not recorded in the atmosphere. These results are compared to observations of switching at Fuego volcano, Guatemala. We conclude that at intermediate magma viscosities, the development of stable degassing pathways open to the atmosphere will allow HT generated in the conduit to be transmitted into the atmosphere. Further, subtle changes in magma properties and supply rate may control whether SHT or SAHT is recorded, providing information about the state of the shallow conduit and vent at active volcanoes.
Link between Coulomb stress changes and seismic activation in the eastern Marmara sea after the 1999, Izmit (Turkey), earthquake
Authors: Durand Virginie , Bouchon Michel , Karabulut Hayrullah , Marsan David , Schmittbuhl Jean
Published: April 2013

We investigate the effect of dynamic and static stress changes produced by the 1999 Izmit earthquake, on four preexisting seismic clusters located in the eastern Marmara sea, beyond the western termination of the earthquake rupture. These four clusters show long‐lasting modifications in their seismicity rate. We observe that these seismic activity variations are related to stress changes. Dynamic stress pulses activate strike‐slip faulting instantaneously, but in the absence of a concomitant static Coulomb stress increase, this activation is short lived. Indeed, a large dynamic stress combined with a negative static Coulomb stress may result in an immediate activation followed by the occurrence of a seismicity shadow. In contrast, the activation of extensional clusters begins slowly and takes a few days to fully develop. It is also remarkably long lasting and does not follow a classical Omori decay. More than 10 years after the earthquake, the extensional clusters located near the termination of the rupture, where static stress and pressure changes were high, are still activated.
Land water contribution to sea level from GRACE and Jason‐1measurements
Authors: Jensen L. , Rietbroek R. , Kusche J.
Published: April 2013

We investigate the effect of water storage changes in the world's major hydrological catchment basins on global and regional sea level change at seasonal and long‐term time scales. In a joint inversion using GRACE and Jason‐1 data, we estimate the time‐dependent sea level contributions of 124 spatial patterns (“fingerprints”) including glacier and ice sheet melting, thermal expansion, changes in the terrestrial hydrological cycle, and glacial isostatic adjustment. Particularly, for hydrological storage changes, we derive fingerprints of the 33 world's largest catchment basins, assuming mass distributions derived from the leading EOFs of total water storage in the WaterGap Global Hydrological Model (WGHM). From our inversion, we estimate a contribution of terrestrial hydrological cycle changes to global mean sea level of − 0.20 ± 0.04 mm/yr with an annual amplitude of 6.6 ± 0.5 mm for August 2002 to July 2009. Using only GRACE data in the inversion and comparing to hydrological changes derived from GRACE data directly using a basin averaging method shows a good agreement on a global scale, but considerable differences are found for individual catchment basins (up to 180%). Hydrological storage change estimates in 33 basins from the GRACE/Jason fingerprint inversion indicate a trend 46% smaller and an annual amplitude 43% bigger compared to WGHM‐derived storage changes. Mapping the hydrological trends to regional sea level reveals the strongest sea level rise along the coastlines of South America (max 0.9 mm/yr) and West Africa (max 0.4 mm/yr), whereas around Alaska and Australia, we find the hydrological component of sea level falling (min −2.0 mm/yr and −0.9 mm/yr).
Eastern Indian Ocean warming associated with the negative Indian Ocean dipole: A case study of the 2010 event
Authors: Horii Takanori , Ueki Iwao , Ando Kentaro , Mizuno Keisuke
Published: April 2013

Warm sea surface temperature (SST) anomalies of more than 1 °C occurred in the southeastern tropical Indian Ocean and peaked during August to October 2010. The anomalous SST warming was associated with the negative phase of the Indian Ocean dipole (IOD) phenomenon. In this study, observational data from a moored buoy were used together with satellite and atmospheric reanalysis data sets to clarify the processes that produced the anomalously warm SST in 2010. We focused on the location 5°S, 95°E where in situ measurements of more than 10 years by a moored buoy were available. The buoy observations captured the oceanic conditions related to the anomalous warming event of 2010. Heat balance analysis demonstrated that air‐sea heat fluxes and horizontal heat advections mainly account for the mixed layer temperature variation. Reduced latent heat loss had a major role in producing the warm SST anomalies. Meridional heat advection also contributed to the warm SST anomalies where the southeastward surface current brought warmer water to the southeastern tropical Indian Ocean. The present results from the observations suggest that air‐sea heat exchanges play an active role in the SST anomalies in the southeastern tropical Indian Ocean during the negative IOD. In contrast, in the case of cold SST anomalies in the eastern Indian Ocean during the positive IOD, ocean heat advections mainly control the mixed layer temperature variation. These results suggest that the IOD includes different feedback mechanisms in its positive and negative phases.
Evaluation of near‐surface air temperature and specific humidity from hybrid global products and their impact on latent heat flux in the North Indian Ocean
Authors: Rahaman H. , Ravichandran M.
Published: April 2013

Daily near‐surface air temperature (Ta) and specific humidity (Qa) from three hybrid flux products, namely, Coordinated Ocean‐Ice Reference Experiments version II (CORE‐II), Objectively Analyzed Air‐Sea Fluxes (OAFlux), and Air‐Sea Fluxes for the Global Tropical Oceans (TropFlux), are evaluated using in situ data over the North Indian Ocean. The analysis shows that the root‐mean‐square error (RMSE) value of Ta is ~0.5°C for all products. TropFlux captures the daily variability of Ta very well, but it has a systematic deviation in Ta. The large drop in Ta observed during intense rainfall events is very well captured by TropFlux. All products overestimate Qa by 0.3–1.5 g/kg; OAFlux has the smallest systematic deviation, whereas TropFlux has the highest correlation with buoy data. The overestimation of Qa by the products is mainly caused by high values of Qa, in the range of 18–22 g/kg. The RMSE of Qa ranges from 0.92 to 1.79 g/kg, with OAFlux having the lowest values. Latent heat flux (LHF) computed from a bulk algorithm is underestimated by all products, which can be primarily attributed to the positive bias in Qa. In the southern Bay of Bengal, LHF decreases with increasing Qa during winter and summer monsoons. In this region, a change in 1 g/kg Qa can cause about 11–15 W/m2 errors in LHF. The air‐sea humidity difference is linearly related to sea surface temperature for values greater than 28°C, similar to findings for the western Pacific Ocean.
Simulating the formation and fate of dense water in a midlatitude marginal sea during normal and warm winter conditions
Authors: Querin Stefano , Cossarini Gianpiero , Solidoro Cosimo
Published: April 2013

Dense shelf water production and the deep convection process in the Adriatic Sea are investigated, considering two case studies: the first is representative of the present climatic situation, whereas the second may be expected in a scenario characterized by mild winter conditions over the basin. Dense water production and spreading are studied using a high‐resolution implementation of the Massachusetts Institute of Technology general circulation model that is initialized and forced with realistic conditions. This paper provides qualitative and quantitative information on mass transport, dense water pathways, thermohaline structures, and the mixing properties of the basin. In the northern Adriatic shelf, seawater temperature is the key element for winter dense water production because it contributes more relevantly than salinity in determining density. In the southern Adriatic Sea, a small amount of dense water that cascades directly into the pit can be formed on the narrow western shelf only during cold winter conditions. Moreover, open ocean deepwater formation occurs in the middle of the southern basin. In late winter and spring, although only when winter conditions have been sufficiently cold, northern Adriatic dense shelf water forms a subsurface stream of which the densest part rapidly sinks in the southern pit along the shelf break, whereas its lighter part flows southward and reaches the Otranto Strait. The frequent occurrence of mild winter conditions could lead to lower dense water production, with a reduced dense water flow from the Adriatic Sea to the Ionian Sea and a potential great impact on the eastern Mediterranean thermohaline circulation.
Traditional quasi‐geostrophic modes and surface quasi‐geostrophic solutions in the Southwestern Atlantic
Authors: Rocha Cesar B. , Tandon Amit , da Silveira Ilson C. A. , Lima Jose Antonio M.
Published: April 2013

We investigate whether the Quasi‐geostrophic (QG) modes and the Surface Quasi‐geostrophic (SQG) solutions are consistent with the vertical structure of the subinertial variability off southeast Brazil. The first‐order empirical orthogonal function (EOF) of current meter time series is reconstructed using different QG mode combinations; the first EOF is compared against SQG solutions. At two out of three moorings, the traditional flat‐bottom barotropic (BT) and first baroclinic (BC1) mode combination fails to represent the observed sharp near‐surface decay, although this combination contains up to 78% of the depth‐integrated variance. A mesoscale broad‐band combination of flat‐bottom SQG solutions is consistent with the near‐surface sharp decay, accounting for up to 85% of the first EOF variance. A higher‐order QG mode combination is also consistent with the data. Similar results are obtained for a rough topography scenario, in which the velocity vanishes at the bottom. The projection of the SQG solutions onto the QG modes confirms that these two models are mutually dependent. Consequently, as far as the observed near‐surface vertical structure is concerned, SQG solutions and four‐QG mode combination are indistinguishable. Tentative explanations for such vertical structures are given in terms of necessary conditions for baroclinic instability. “Charney‐like” instabilities, or, surface‐intensified “Phillips‐like” instabilities may explain the SQG‐like solutions at two moorings; traditional “Phillips‐like” instabilities may rationalize the BT/BC1 mode representation at the third mooring. These results point out to the presence of a richer subinertial near‐surface dynamics in some regions, which should be considered for the interpretation and projection of remotely sensed surface fields to depth.
Development of a variational data assimilation system for the diurnal cycle of sea surface temperature
Authors: While J. , Martin M.
Published: April 2013

A variational data assimilation system based on an incremental 4D‐Var approach is proposed for use with a zero‐dimensional model of the diurnal cycle of sea surface temperature (SST). Traditional 4D‐Var, which seeks to find the initial state of a system, is not appropriate for diurnal SST which is a wind and heat flux driven system that has only a limited memory of its prior state. Instead the proposed assimilation system corrects both the initial SST and the heat and wind fluxes applied throughout the day. The assimilation system is tested using ensembles in a set of idealized twin experiments. In these tests controlling parameters are varied around reasonable “default” values with the quality of the analyses assessed against a known “truth”. Within our tests data assimilation is shown to improve diurnal SST under most circumstances. Analyzed heat fluxes are also sometimes improved, although the improvement is much less than that observed for diurnal SST. The system was not found to improve the wind stress. The only circumstances where diurnal SST was not found to be improved by the assimilation were where either observational errors were large (greater than 0.5 K in our tests), or biases in the observations were too big (less than −0.3 K or greater than 0.2 K). The non‐Gaussian behavior of the wind stress was found to have an impact on the assimilation in low‐wind conditions and under these conditions the best analyses were obtained by artificially inflating the observation error.
Rates and mechanisms of turbulent dissipation and mixing in the Southern Ocean: Results from the Diapycnal and Isopycnal Mixing Experiment in the Southern Ocean (DIMES)
Authors: Sheen K. L. , Brearley J. A. , Naveira Garabato A. C. , Smeed D. A. , Waterman S. , Ledwell J. R. , Meredith M. P. , St. Laurent L. , Thurnherr A. M. , Toole J. M. , Watson A. J.
Published: April 2013

The spatial distribution of turbulent dissipation rates and internal wavefield characteristics is analyzed across two contrasting regimes of the Antarctic Circumpolar Current (ACC), using microstructure and finestructure data collected as part of the Diapycnal and Isopycnal Mixing Experiment in the Southern Ocean (DIMES). Mid‐depth turbulent dissipation rates are found to increase from
in the Southeast Pacific to
in the Scotia Sea, typically reaching
within a kilometer of the seabed. Enhanced levels of turbulent mixing are associated with strong near‐bottom flows, rough topography, and regions where the internal wavefield is found to have enhanced energy, a less‐inertial frequency content and a dominance of upward propagating energy. These results strongly suggest that bottom‐generated internal waves play a major role in determining the spatial distribution of turbulent dissipation in the ACC. The energy flux associated with the bottom internal wave generation process is calculated using wave radiation theory, and found to vary between 0.8 mW m−2 in the Southeast Pacific and 14 mW m−2 in the Scotia Sea. Typically, 10%–30% of this energy is found to dissipate within 1 km of the seabed. Comparison between turbulent dissipation rates inferred from finestructure parameterizations and microstructure‐derived estimates suggests a significant departure from wave‐wave interaction physics in the near‐field of wave generation sites.
Experimental study of acid‐sulfate alteration of basalt and implications for sulfate deposits on Mars
Authors: McCollom Thomas M. , Robbins Mark , Moskowitz Bruce , Berquó Thelma S. , Jöns Niels , Hynek Brian M.
Published: April 2013

Acid‐sulfate alteration of basalt by SO2‐bearing volcanic vapors has been proposed as one possible origin for sulfate‐rich deposits on Mars. To better define mineralogical signatures of acid‐sulfate alteration, laboratory experiments were performed to investigate alteration pathways and geochemical processes during reaction of basalt with sulfuric acid. Pyroclastic cinders composed of phenocrysts including plagioclase, olivine, and augite embedded in glass were reacted with sulfuric acid at 145 °C for up to 137 days at a range of fluid : rock ratios. During the experiments, the phenocrysts reacted rapidly to form secondary products, while the glass was unreactive. Major products included amorphous silica, anhydrite, and Fe‐rich natroalunite, along with minor iron oxides/oxyhydroxides (probably hematite) and trace levels of other sulfates. At the lowest fluid : rock ratio, hexahydrite and an unidentified Fe‐silicate phase also occurred as major products. Reaction‐path models indicated that formation of the products required both slow dissolution of glass and kinetic inhibitions to precipitation of a number of minerals including phyllosilicates and other aluminosilicates as well as Al‐ and Fe‐oxides/oxyhydroxides. Similar models performed for Martian basalt compositions predict that the initial stages of acid‐sulfate alteration of pyroclastic deposits on Mars should result in formation of amorphous silica, anhydrite, Fe‐bearing natroalunite, and kieserite, along with relict basaltic glass. In addition, analysis of the experimental products indicates that Fe‐bearing natroalunite produces a Mössbauer spectrum closely resembling that of jarosite, suggesting that it should be considered an alternative to the component in sulfate‐rich bedrocks at Meridiani Planum that has previously been identified as jarosite.
Rocket dust storms and detached dust layers in the Martian atmosphere
Authors: Spiga Aymeric , Faure Julien , Madeleine Jean‐Baptiste , Määttänen Anni , Forget François
Published: April 2013

Airborne dust is the main climatic agent in the Martian environment. Local dust storms play a key role in the dust cycle; yet their life cycle is poorly known. Here we use mesoscale modeling that includes the transport of radiatively active dust to predict the evolution of a local dust storm monitored by OMEGA on board Mars Express. We show that the evolution of this dust storm is governed by deep convective motions. The supply of convective energy is provided by the absorption of incoming sunlight by dust particles, rather than by latent heating as in moist convection on Earth. We propose to use the terminology “rocket dust storm,” or conio‐cumulonimbus, to describe those storms in which rapid and efficient vertical transport takes place, injecting dust particles at high altitudes in the Martian troposphere (30–50 km). Combined to horizontal transport by large‐scale winds, rocket dust storms produce detached layers of dust reminiscent of those observed with Mars Global Surveyor and Mars Reconnaissance Orbiter. Since nighttime sedimentation is less efficient than daytime convective transport, and the detached dust layers can convect during the daytime, these layers can be stable for several days. The peak activity of rocket dust storms is expected in low‐latitude regions at clear seasons (late northern winter to late northern summer), which accounts for the high‐altitude tropical dust maxima unveiled by Mars Climate Sounder. Dust‐driven deep convection has strong implications for the Martian dust cycle, thermal structure, atmospheric dynamics, cloud microphysics, chemistry, and robotic and human exploration.
An assemblage of lava flow features on Mercury
Authors: Byrne Paul K. , Klimczak Christian , Williams David A. , Hurwitz Debra M. , Solomon Sean C. , Head James W. , Preusker Frank , Oberst Jürgen
Published: April 2013

In contrast to other terrestrial planets, Mercury does not possess a great variety of volcanic features, its history of volcanism instead largely manifest by expansive smooth plains. However, a set of landforms at high northern latitudes on Mercury resembles surface flow features documented on Earth, the Moon, Mars, and Venus. The most striking of such landforms are broad channels that host streamlined islands and that cut through the surrounding intercrater plains. Together with narrower, more sinuous channels, coalesced depressions, evidence for local flooding of intercrater plains by lavas, and a first‐order analysis of lava flow rates, the broad channels define an assemblage of flow features formed by the overland flow of, and erosion by, voluminous, high‐temperature, low‐viscosity lavas. This interpretation is consistent with compositional data suggesting that substantial portions of Mercury's crust are composed of magnesian, iron‐poor lithologies. Moreover, the proximity of this partially flooded assemblage to extensive volcanic plains raises the possibility that the formation of these flow features may preface total inundation of an area by lavas emplaced in a flood mode and that they escaped complete burial only due to a waning magmatic supply. Finally, that these broad channels on Mercury are volcanic in nature yet resemble outflow channels on Mars, which are commonly attributed to catastrophic water floods, implies that aqueous activity is not a prerequisite for the formation of such distinctive landforms on any planetary body.
Titan's atmosphere simulation experiment using continuum UV‐VUV synchrotron radiation
Authors: Peng Z. , Gautier T. , Carrasco N. , Pernot P. , Giuliani A. , Mahjoub A. , Correia J.‐J. , Buch A. , Bénilan Y. , Szopa C. , Cernogora G.
Published: April 2013

A new reactor, named APSIS for Atmospheric Photochemistry Simulated by Synchrotron, is designed for simulating the reactivity occurring in planetary upper atmospheres. In this reactor, a gas mixture roughly reproducing Titan's main atmosphere composition (N2/CH4 = 90/10) is irradiated by a continuous spectrum in the 60−350 nm range, provided by the DISCO beamline at the SOLEIL synchrotron radiation facility. This spectral range enables the dissociation and ionization of N2 and CH4, as observed in plasma reactors and Titan's ionosphere. The neutral products are detected in situ by quadrupole mass spectrometry and collected with a cryogenic trap for ex situ analysis by gas chromatography‐mass spectrometry. The detected reaction products include C2, C3, C4, and probably C5 organic compounds, with important amounts of nitrogen‐bearing species: HCN, CH3CN, and C2N2. Neutral mass spectra obtained with APSIS are compared with Ion and Neutral Mass Spectrometer experiments of the Cassini space probe in the upper Titan atmosphere and with other results of current Titan atmosphere chemistry laboratory simulations.