bluuebunny/crossref_metadata_2025_split huggingface dataset:
Impacts of silver nanoparticles on cellular and transcriptional activity of nitrogen-cycling bacteria
Authors: Yang Yu , Wang Jing , Xiu Zongming , Alvarez Pedro J. J. 
Published: April 2013

Abstract

The widespread use of silver nanoparticles (AgNPs) raises the potential for environmental releases that could impact microbial ecosystem services. In the present study, the authors address how the AgNPs and Ag+ that they release may impact nitrogen-cycling bacteria. The authors studied the cellular and transcriptional response of the denitrifier Pseudomonas stutzeri, the nitrogen fixer Azotobacter vinelandii, and the nitrifier Nitrosomonas europaea exposed to 35 nm (carbon-coated) AgNPs or to Ag+ (added as AgNO3). Based on minimum inhibitory concentrations (MICs), Ag+ was 20 times to 48 times more toxic to the tested strains than AgNPs (including Ag+ released during exposure). Exposure to sublethal concentrations of AgNPs or Ag+ (representing 10% of the respective MIC for AgNO3) resulted in no significant effect on the expression of the denitrifying genes narG, napB, nirH, and norB in P. stutzeri or the nitrogen-fixing genes nifD, nifH, vnfD, and anfD in A. vinelandii, whereas nitrifying genes (amoA1 and amoC2) in N. europaea were upregulated (2.1- to 3.3-fold). This stimulatory effect disappeared at higher silver concentrations (60% of the Ag+ MIC), and toxicity was exerted at concentrations higher than 60% of the Ag+ MIC. The MIC for N. europaea was 8 times to 24 times lower than for the other strains, indicating higher susceptibility to AgNPs. This was corroborated by the lower half-lethal concentration for N. europaea (87 µg/L) compared with P. stutzeri (124 µg/L) and A. vinelandii (&gt;250 µg/L) when cells were exposed with Ag+ for 24 h in 1 mM bicarbonate buffer. This suggests that ammonia oxidation would be the most vulnerable nitrogen-cycling process in wastewater treatment plants receiving AgNPs and in agricultural soils amended with biosolids that concentrate them. Environ Toxicol Chem 2013;32:1488–1494. © 2013 SETAC
Urban tunnels in the Czech Republic / Innerstädtische Tunnel in der Tschechischen Republik
Authors: Butovic̆ Alexandr , S̆ourek Pavel , Horák Vlastimil 
Published: April 2013

AbstractUrban road tunnels have only been built in four towns in the Czech Republic. Their purpose is mostly environmental, with construction being enforced by ever growing requirements for environmental protection. Currently there are twelve urban road tunnels operating in the Czech Republic: six in Prague, four in Brno and single tunnels in Liberec and Jihlava. The Blanka complex of tunnels in Prague is currently under construction and will become the longest tunnel in the Czech Republic in 2014.Innerstädtische Straßentunnel wurden bisher nur in vier tschechischen Städten gebaut, und dabei sind meist umwelttechnische Überlegungen ausschlaggebend gewesen. Ihr Bau wurde durchgesetzt aufgrund der immer stärkeren Anforderungen an den Umweltschutz. Zurzeit gibt es in der Tschechischen Republik zwölf städtische Straßentunnel in Betrieb: sechs in Prag, vier in Brünn und jeweils ein Tunnel in Reichenberg und Jihlava. Zusätzlich wird der Blanka Tunnelkomplex in Prag gerade gebaut. Bei Fertigstellung 2014 wird er der längste Tunnel der Tschechischen Republik sein.
Prague Metro / Die Prager Metro
Authors: Hasík Otakar , Růz̆ic̆ka Jir̆í 
Published: April 2013

AbstractThe Prague Metro today forms a very reliable backbone of the Prague mass transit system. The network consisting of three radial lines (A, B and C) with interchanges in the city centre developed gradually. The paper is devoted to engineering solutions for tunnels and tunnel construction methods. The first section describes the origins of the system in the 1970s and its history through the 1970s, 1980s and 1990s. The New Austrian Tunnelling Method arrived in the modern era. The first applications of the method were primarily associated with the construction of the fourth extension of Line B (Metro Line IV.B, followed by the 4th operating section of Line C (Line IV.C). The design work for this part of the metro network was probably the longest and most difficult and it resulted in extremely interesting technical solutions. The main part of the paper is dedicated to the current development of operating section V.A, which commenced in the autumn of 2009. The section is 6,134 m long and contains four stations, of which three are being built by mining methods.Die Prager Metro stellt heute ein sehr verlässliches Rückgrat des Prager Personennahverkehrs dar. Das U‐Bahn‐Netz, bestehend aus drei Linien (A, B und C) mit Umsteigestationen in der Innenstadt, hat sich fortlaufend entwickelt. Dieser Beitrag widmet sich den dabei verwendeten verfahrenstechnischen Lösungen für den Tunnelbau und unterschiedlichen Tunnelbaumethoden. Im ersten Abschnitt werden die Ursprünge des Systems in den 1970er‐Jahren und seine historische Entwicklung während der 1970er‐, 1980er‐ und 1990er‐Jahre beschrieben. Die Neue Österreichische Tunnelbaumethode erreichte die Neuzeit. Eine der ersten Anwendungen dieser Methode stellte der Bau der vierten Erweiterung der Linie B (Metro Linie IV.B) dar, gefolgt vom vierten Bauabschnitt der Linie C (Linie IV.C). Die Planungsarbeiten für diesen Bauabschnitt der Metro waren wohl die Längsten und Schwierigsten und resultierten in einer höchst interessanten, technischen Lösung. Der Hauptteil des Beitrags widmet sich den derzeitigen Baumaßnahmen am Bauabschnitt V.A, welche im Herbst 2009 begonnen wurden. Dieser Abschnitt ist 6.134 m lang und beinhaltet vier Stationen, von denen drei bergmännisch hergestellt werden.
Czech tunnelling abroad / Tschechischer Tunnelbau im Ausland
Authors: Stehlík Ermín 
Published: April 2013

AbstractThe paper summarizes the activities of Czech tunnelling consultants and contractors, mainly after 1989. After the political changes, consultants and contractors were able to obtain access to projects abroad. The contractors first started their presence in the European tunnelling market as subcontractors, and later managed to tender for tunnelling contracts on their own. Iceland, Croatia and Finland have all witnessed successful performance of Metrostav a.s. and Subterra a.s. is currently working in Serbia. Consultants started their activities abroad after 1989, when foreign consultancy firms Mott MacDonald and D2 Consult established branches in the Czech Republic, which at present are working on projects in various countries in Europe and Asia. Metroprojekt Praha a.s. (without a foreign partner) is currently involved in consultancy activities in Sofia, Bulgaria.Dieser Beitrag fasst die Tätigkeiten tschechischer Tunnelbau‐Consultants und Tunnelbau‐Unternehmen, vornehmlich nach 1989, zusammen. Nach dem politischen Umbruch waren Baufirmen und Sachverständige in der Lage, Zugang zu ausländischen Tunnelbauprojekten zu erlangen, wobei die Baufirmen im europäischen Tunnelgeschäft dabei zunächst als Subunternehmer auftraten. Später nahmen sie eigenständig an Ausschreibungen teil. Sowohl in Island, Kroatien und Finnland als auch derzeit in Serbien kann man die erfolgreiche Durchführung verschiedener Projekte durch Metrostav a.s. bzw. Subterra a.s. beobachten. Consultants starteten ihre Tätigkeit im Ausland ab 1989, nachdem Mott MacDonald und D2 Consult Zweigstellen in der Tschechischen Republik etabliert hatten, welche derzeit an verschiedenen Projekten in Europa und Asien arbeiten. Darüber hinaus ist Metroprojekt Praha a.s. (ohne ausländischen Partner) an Beratertätigkeiten in Sofia, Bulgarien beteiligt.
Interannual sea surface salinity variations observed in the tropical North Pacific Ocean
Authors: Li Yuanlong , Wang Fan , Han Weiqing 
Published: April 2013

AbstractAnalysis of observational data sets reveals pronounced interannual variations of sea surface salinity (SSS) in the tropical North Pacific (7°N–15°N) during 2000–2012. SSS anomalies with maximum magnitudes >0.2 occur in the central Pacific and translate westward at a speed of 15–20 cm s–1. The signals are weakened during their westward movement but reinforced in the Philippine Sea. Budget analysis for the mixed layer salinity suggests that in the central Pacific, El Niño–Southern Oscillation‐related atmospheric freshwater forcing and ocean advection changes are both important in generating and maintaining these large SSS anomalies. In the advection term, the most contributing component is the meridional Ekman advection induced by trade winds. These SSS anomalies are subsequently carried westward by the North Equatorial Current, which is the primary cause of SSS variations in the Philippine Sea. Freshwater forcing is also at work in the Philippine Sea, but its role is generally secondary.
How can anomalous western North Pacific Subtropical High intensify in late summer?
Authors: Xiang Baoqiang , Wang Bin , Yu Weidong , Xu Shibin 
Published: April 2013

AbstractThe western North Pacific (WNP) Subtropical High (WNPSH) is a controlling system for East Asian Summer monsoon and tropical storm activities, whereas what maintains the anomalous summertime WNPSH has been a long‐standing riddle. Here we demonstrate that the local convection‐wind‐evaporation‐SST (CWES) feedback relying on both mean flows and mean precipitation is key in maintaining the WNPSH, while the remote forcing from the development of the El Niño/Southern Oscillation is secondary. Strikingly, the majority of strong WNPSH cases exhibit anomalous intensification in late summer (August), which is dominantly determined by the seasonal march of the mean state. That is, enhanced mean precipitation associated with strong WNP monsoon trough in late summer makes atmospheric response much more sensitive to local SST forcing than early summer.
Linking permeability to crack density evolution in thermally stressed rocks under cyclic loading
Authors: Faoro I. , Vinciguerra S. , Marone C. , Elsworth D. , Schubnel A. 
Published: April 2013

AbstractTo improve our understanding of the complex coupling between circulating fluids and the development of crack damage, we performed flow‐through tests on samples of Etna basalt and Westerly granite that were cyclically loaded by deviatoric stresses. The basalt was naturally microfractured, while the relatively crack‐free Westerly granite was thermally pretreated to 500°C and 800°C to generate microcrack damage. Samples were repeatedly loaded and then unloaded under deviatoric stress paths and ultimately to failure. Permeability and water volume content were measured throughout the loading history together with the differential stress. Permeability decreases at low differential stresses and increases at intermediate differential stresses up to a steady value at failure. We use water volume content as a proxy for fluid storage and show that both permeability and storage evolve with damage and evolution of crack density. We use crack models to represent the evolution of permeability as a function of loading state and are able to independently link it to the observed evolution of deformability, used as an independent measure of crack density.
Incidence and risk factors of significant carotid artery stenosis in asymptomatic survivors of head and neck cancer after radiotherapy
Authors: Dorth Jennifer A. , Patel Pretesh R. , Broadwater Gloria , Brizel David M. 
Published: April 2013

BackgroundThe incidence and risk factors of carotid artery stenosis in asymptomatic patients after head and neck radiation therapy (RT) are unknown.MethodsThis retrospective study reviewed asymptomatic patients treated with RT for head and neck cancer from 2000 to 2009 who underwent screening carotid ultrasound.ResultsTwo hundred twenty‐four patients were included, the majority of whom had stage III to IV disease and received cisplatin‐based chemotherapy. Median time from RT completion to last carotid ultrasound was 3 years. Actuarial rate of carotid artery stenosis at 4 years was 14% (95% confidence interval [CI], 4% to 22%). Multivariate analysis revealed that carotid artery stenosis was associated with Framingham risk factors (hazard ratio [HR], 1.6 per factor; 95% CI, 1.2–2.2; p = .003). Among 135 patients treated with intensity‐modulated radiation therapy (IMRT), the HR for carotid artery stenosis was 1.4 for every 10 Gy increase in mean RT dose to the carotid bulb plus 2 cm (95% CI, 0.8–2.4; p = .35).ConclusionPrevention and screening programs should be considered for head and neck cancer survivors given the high risk of carotid artery stenosis. © 2013 Wiley Periodicals, Inc. Head Neck 36: 215–219, 2014
Species sensitivity distribution evaluation for chronic nickel toxicity to marine organisms
Authors: DeForest David K , Schlekat Christian E 
Published: April 2013

Abstract
In Europe, the European Union's Existing Substances Regulation (EEC 793/93), the REACH Regulation, and Water Framework Directive all share common guidance for conducting environmental effects assessments, which can be further used to derive predicted no effect concentrations (PNECs) and environmental quality standards (EQS) for chemical substances. To meet the criteria for using a species sensitivity distribution (SSD) in the effects assessment of Ni for marine organisms, chronic toxicity data from the published scientific literature were augmented with toxicity testing of several additional marine species including: a unicellular alga (Dunalliela tertiolecta), a diatom (Skeletonema costatum), 2 macroalgae (Champia parvula, Macrocystis pyrifera), 2 mollusks (Crassostrea gigas, Mytilus galloprovincialis), 2 echinoderms (Dendraster excentricus, Strongylocentrotus purpuratus), a polychaete (Neanthes arenaceodentata), and a fish (Cyprinodon variegatus). Based on this updated database, which includes chronic Ni toxicity data for a total of 17 marine species, HC5 values (hazardous concentrations to 5% of the species) were derived using an SSD. The most sensitive species is a tropical sea urchin from the Caribbean region, Diadema antillarum, which has an EC10 that is approximately 6-fold less than the EC10 for the second most sensitive species tested. There is some uncertainty in the representativeness of D. antillarum to temperate European marine waters because 1) a European sea urchin species (Paracentrotus lividus) is approximately 48-fold less sensitive to Ni, and (2) ambient marine Ni concentrations in at least some European waters closely approach the D. antillarum EC10. The HC5 values with and without D. antillarum included in the SSD are 3.9 and 20.9 μg/L, respectively. Site-specific toxicity testing with local species may be warranted for locations where Ni concentrations fall between the range in HC5s of 3.9 to 20.9 μg/L. Integr Environ Assess Manag 2013;9:580–589. © 2013 SETAC
Hydroxyapatite/collagen nanocomposite‐coated titanium rod for achieving rapid osseointegration onto bone surface
Authors: Uezono Masayoshi , Takakuda Kazuo , Kikuchi Masanori , Suzuki Shoichi , Moriyama Keiji 
Published: April 2013

AbstractThis article proposes less‐invasive subperiosteal bone‐bonding devices capable of realizing rapid osseointegration and the acquisition of fundamental knowledge required for their development. Three candidates were prepared: titanium rod specimens with a machined surface (Bare), hydroxyapatite (HAp) coating, and hydroxyapatite/collagen (HAp/Col) nanocomposite coating. To investigate bone formation around these rods, each specimen was placed under the periosteum of a male Sprague‐Dawley rat calvarium. Four weeks after surgery, the samples were evaluated via histomorphometrical analyses and bonding strength tests. All the Bare specimens and more than half of the HAp specimens were encapsulated with fibrous tissue, whereas all the HAp/Col specimens were almost completely surrounded by new bone tissue without encapsulation. Histomorphometrical analyses showed that the HAp/Col group had the greatest bone contact ratio among all candidates (p < 0.05). Further, a bonding strength test indicated that the HAp/Col group exhibited the greatest bonding strength to bone (p < 0.05). Thus, HAp/Col‐coated rods are considered as the best candidate materials for achieving rapid osseointegration onto a bone surface. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2013.
A comparison of bone quality at the distal radius between Asian and white adolescents and young adults: An HR-pQCT study
Authors: Kim SoJung , Macdonald Heather M , Nettlefold Lindsay , McKay Heather A 
Published: April 2013

ABSTRACT

Paradoxically, Asians have lower areal bone mineral density (aBMD), but their rates of hip and wrist fractures are lower than whites. Therefore, we used high-resolution pQCT (HR-pQCT) to determine whether differences in bone macrostructure and microstructure, BMD, and bone strength at the distal radius were apparent in Asian (n = 91, 53 males, 38 females, [mean ± SD] 17.3 ± 1.5 years) and white (n = 89, 46 males, 43 females, 18.1 ± 1.8 years) adolescents and young adults. HR-pQCT outcomes included total BMD (Tt.BMD), trabecular bone volume fraction (BV/TV), and trabecular number (Tb.N), thickness (Tb.Th), and separation (Tb.Sp). We used an automated segmentation algorithm to determine total bone area (Tt.Ar), and cortical BMD (Ct.BMD), porosity (Ct.Po), and thickness (Ct.Th), and we applied finite element (FE) analysis to HR-pQCT scans to estimate bone strength. We fit sex-specific multivariable regression models to compare bone outcomes between Asians and whites, adjusting for age, age at menarche (girls), lean mass, ulnar length, dietary calcium intake, and physical activity. In males, after adjusting for covariates, Asians had 11% greater Tt.BMD, 8% greater Ct.BMD, and 25% lower Ct.Po than whites (p &lt; 0.05). Also, Asians had 9% smaller Tt.Ar and 27% greater Ct.Th (p &lt; 0.01). In females, Asians had smaller Tt.Ar than whites (16%, p &lt; 0.001), but this difference was not significant after adjusting for covariates. Asian females had 5% greater Ct.BMD, 12% greater Ct.Th, and 11% lower Tb.Sp than whites after adjusting for covariates (p &lt; 0.05). Estimated bone strength did not differ between Asian and white males or females. Our study supports the notion of compensatory elements of bone structure that sustain bone strength; smaller bones as observed between those of Asian origin compared with white origin have, on average, more dense, less porous, and thicker cortices. Longitudinal studies are needed to determine whether ethnic differences in bone structure exist in childhood, persist into old age, and whether they influence fracture risk.
Altered thermogenesis and impaired bone remodeling in Misty mice
Authors: Motyl Katherine J , Bishop Kathleen A , DeMambro Victoria E , Bornstein Sheila A , Le Phuong , Kawai Masanobu , Lotinun Sutada , Horowitz Mark C , Baron Roland , Bouxsein Mary L , Rosen Clifford J 
Published: April 2013

ABSTRACT

Fat mass may be modulated by the number of brown-like adipocytes in white adipose tissue (WAT) in humans and rodents. Bone remodeling is dependent on systemic energy metabolism and, with age, bone remodeling becomes uncoupled and brown adipose tissue (BAT) function declines. To test the interaction between BAT and bone, we employed Misty (m/m) mice, which were reported be deficient in BAT. We found that Misty mice have accelerated age-related trabecular bone loss and impaired brown fat function (including reduced temperature, lower expression of Pgc1a, and less sympathetic innervation compared to wild-type (+/ +)). Despite reduced BAT function, Misty mice had normal core body temperature, suggesting heat is produced from other sources. Indeed, upon acute cold exposure (4°C for 6 hours), inguinal WAT from Misty mice compensated for BAT dysfunction by increasing expression of Acadl, Pgc1a, Dio2, and other thermogenic genes. Interestingly, acute cold exposure also decreased Runx2 and increased Rankl expression in Misty bone, but only Runx2 was decreased in wild-type. Browning of WAT is under the control of the sympathetic nervous system (SNS) and, if present at room temperature, could impact bone metabolism. To test whether SNS activity could be responsible for accelerated trabecular bone loss, we treated wild-type and Misty mice with the β-blocker, propranolol. As predicted, propranolol slowed trabecular bone volume/total volume (BV/TV) loss in the distal femur of Misty mice without affecting wild-type. Finally, the Misty mutation (a truncation of DOCK7) also has a significant cell-autonomous role. We found DOCK7 expression in whole bone and osteoblasts. Primary osteoblast differentiation from Misty calvaria was impaired, demonstrating a novel role for DOCK7 in bone remodeling. Despite the multifaceted effects of the Misty mutation, we have shown that impaired brown fat function leads to altered SNS activity and bone loss, and for the first time that cold exposure negatively affects bone remodeling.
Realizing the potential of gene-based molecular therapies in bone repair
Authors: Rose Laura , Uludağ Hasan 
Published: April 2013

ABSTRACT

A better understanding of osteogenesis at genetic and biochemical levels is yielding new molecular entities that can modulate bone regeneration and potentially act as novel therapies in a clinical setting. These new entities are motivating alternative approaches for bone repair by utilizing DNA-derived expression systems, as well as RNA-based regulatory molecules controlling the fate of cells involved in osteogenesis. These sophisticated mediators of osteogenesis, however, pose unique delivery challenges that are not obvious in deployment of conventional therapeutic agents. Viral and nonviral delivery systems are actively pursued in preclinical animal models to realize the potential of the gene-based medicines. This article will summarize promising bone-inducing molecular agents on the horizon as well as provide a critical review of delivery systems employed for their administration. Special attention was paid to synthetic (nonviral) delivery systems because they are more likely to be adopted for clinical testing because of safety considerations. We present a comparative analysis of dose-response relationships, as well as pharmacokinetic and pharmacodynamic features of various approaches, with the purpose of clearly defining the current frontier in the field. We conclude with the authors' perspective on the future of gene-based therapy of bone defects, articulating promising research avenues to advance the field of clinical bone repair. © 2013 American Society for Bone and Mineral Research
The role of vitamin D in improving physical performance in the elderly
Authors: Lagari Violet , Gómez-Marín Orlando , Levis Silvina 
Published: April 2013

ABSTRACT

There is an ongoing debate over the role of serum 25(OH) vitamin D [25(OH)D] levels in maintaining or improving physical performance and muscle strength. Much of the controversy is because of the variability between studies in participants' characteristics, baseline serum 25(OH)D levels, and baseline physical functioning. The aim of this ancillary study conducted within a randomized controlled clinical trial was to investigate whether supplementation with 400 or 2000 IU vitamin D3 daily for 6 months would improve measures of physical performance and muscle strength in a community-dwelling elderly population aged 65 to 95 years. Those with the slowest gait speed improved their ability to do chair-stand tests after vitamin D supplementation. This finding remained significant after controlling for potential confounding variables. There was also an inverse correlation between serum 25(OH)D levels and fat mass index (FMI) among women, suggesting that higher supplementation with vitamin D is needed as weight increases. The results of this study suggest that supplementation with vitamin D may be most beneficial in older populations who have low baseline physical functioning. © 2013 American Society for Bone and Mineral Research.