bluuebunny/crossref_metadata_2025 huggingface dataset:
Redesign of a Phenylalanine Aminomutase into a Phenylalanine Ammonia Lyase
Authors: Bartsch Sebastian , Wybenga Gjalt G. , Jansen Maaike , Heberling Matthew M. , Wu Bian , Dijkstra Bauke W. , Janssen Dick B.
Published: April 2013

An aminomutase, naturally catalyzing the interconversion of (S)‐α‐phenylalanine and (R)‐β‐phenylalanine, was converted into an ammonia lyase catalyzing the nonoxidative deamination of phenylalanine to cinnamic acid by a rational single‐point mutation. It could be shown by crystal structures and kinetic data that the flexibility of the lid that covers the active site decides whether the enzyme acts as a lyase or a mutase. An Arg92Ser mutation destabilized the closed conformation of the lid structure and converted the mutase into a lyase that exhibited up to 44‐fold increased reaction rates in the enantioselective deamination of (R)‐β‐phenylalanine. In addition, the amination rates of cinnamic acid yielding optically pure (S)‐α‐ and (R)‐β‐phenylalanine were doubled. The applicability of the mutant enzyme for kinetic resolution and asymmetric amination could be shown by biocatalysis on a preparative scale.
Campher
Authors: Steinke Katrin , Jose Elena , Siehl Hans‐Ullrich , Zeller Klaus‐Peter , Berger Stefan
Published: April 2013

Campher wurde aus dem Wasserdampfdestillat des Campherbaums durch fraktionierte Destillation isoliert und aus Ethanol umkristallisiert. Die UV‐, CD‐, IR‐ NMR‐ und MS‐Spektren sind vollständig in den supporting informations unter www.chiuz.de wiedergegeben. Die NMR‐ sowie die Massenspektren werden eingehend interpretiert und mit theoretischen Berechnungen der 13C chemischen Verschiebungen verglichen. Das Projekt stellt eine Fortsetzung des Buches “Classics in Spectroscopy” von S. Berger und D. Sicker (Wiley‐VCH 2009) dar.
Biomimetische Oxidationen
Authors: Jaenicke Lothar
Published: April 2013

Biomimese ist die Nachahmung von Lebensvorgängen, sei es physikalisch, chemisch oder physiologisch. Sie ist immer erstrebenswert, weil die Natur aus ihrer äonenlangen Erfahrung, in und mit der Umwelt zu überleben, meist “das Beste daraus gemacht hat”, also: Nachhaltigkeit, Schonung der Ressourcen, Rezyklisierung, Umweltfreundlichkeit, Auskommen mit den Gegebenheiten von Luft, Wasser und Mineralien, wenig wirklich nutzloser Abfall; alles was heute in der Gesellschaft propagiert (und selten realisiert) wird. Aber die Chemiker geben sich Mühe, wieder Image zu gewinnen, indem sie von den grobschlächtigen Verfahren der hemdsärmeligen Pioniere ins Bio(techno)logische – oder Biomimetische gehen.
Removal of Hydrogen Sulfide by Physico‐Biological Filter Using Mixed Rice Husk Silica and Dried Activated Sludge
Authors: Mehdinia Seyed Mahmoud , Latif Puziah Abdul , Taghipour Hassan
Published: April 2013

This study investigated the effectiveness of a new packing material, namely mixed rice husk silica with dried activated sludge for removing H2S. Dried sewage sludge was collected from Putrajaya sewage treatment plant in Malaysia. Rice husk silica was prepared at temperature of 800°C, after acid leaching and mixed with dried sewage sludge to be utilized in a polyvinyl chloride filter. The system was operated under variable conditions of two parameters, different inlet gas concentration and different inlet flow rate. H2S was passed through the filter with one liter of the packing material. More than 99.96% removal efficiency (RE) with empty bed residence time (EBRT) of 90–45 s and 300 ppm inlet concentration was observed. However, the RE decreased to 96.87% with the EBRT of 30 s. The maximum elimination capacity (EC) of 52.32 g/m3/h was obtained with the RE of 96.87% and H2S mass loading rate of 54 g/m3/h, while at the RE of 99.96%, maximum EC was 26.99 g/m3/h with the H2S mass‐loading rate of 27 g/m3/h. A strong significant correlation between increasing of H2S mass loading rate and pressure drop was also detected (p < 0.01). Maximum pressure drop was 3.0 mm H2O after 53 days of operating time, the EBRT of 30 s, and 54 g/m3/h of H2S loading rate. These observations suggest that the mixture of rice husk silica with dried activated sludge is a suitable physico‐biological filter for H2S removal.
Dispersion of Graphene Sheets in Aqueous Solution by Oligodeoxynucleotides
Authors: Liang Li‐Jun , Wu Tao , Kang Yu , Wang Qi
Published: April 2013

Applications of graphene sheets in the fields of biosensors and biomedical devices are limited by their insolubility in water. Consequently, understanding the dispersion mechanism of graphene in water and exploring an effective way to prepare stable dispersions of graphene sheets in water is of vital importance for their application in biomaterials, biosensors, biomedical devices, and drug delivery. Herein, a method for stable dispersion of graphene sheets in water by single‐stranded oligodeoxynucleotides (ssODNs) is studied. Owing to van der Waals interactions between graphene sheets, they undergo layer‐to‐layer (LtL) aggregation in water. Molecular dynamics simulations show that, by disrupting van der Waals interaction of graphene sheets with ssODNs, LtL aggregation of graphene sheets is prevented, and water molecules can be distributed stably between graphene sheets. Thus, graphene sheets are dispersed stably in water in the presence of ssODNs. The effects of size and molarity of ssODNs and noncovalent modification of graphene sheets are also discussed.
Chieftaincy‐Based Community Dispute Resolution: The Case of Sierra Leone
Authors: McIntyre Miller Whitney
Published: April 2013

Sierra Leone suffered a destructive 11‐year civil war that largely left its communities torn apart and in need of vast redevelopment. One of the ways that communities are rebuilding and making efforts to move forward is through the chieftaincy‐based community dispute resolution process. Based on historical norms, this process involves the community leader, or chief, helping to resolve disputes within the community. This article reviews this chieftaincy‐based community dispute resolution process, discusses the types of disputes settled, and provides broader lessons learned for communities who may be interested in truly community‐based dispute resolution.
Linkages between Corporate Sustainability Reporting and Public Policy
Authors: Beare Dan , Buslovich Ruvena , Searcy Cory
Published: April 2013

The purpose of this paper is to explore the linkages between corporate sustainability reporting and public policy. Interviews with experts from 35 different Canadian corporations that produce a sustainability report were held to address this issue. The interviews specifically focused on exploring how public policy influences sustainability reporting, investigating how corporate sustainability reporting influences public policy, and identifying the barriers to linking sustainability reporting with public policy. The majority of participants explained that their corporation's sustainability reporting has not been heavily influenced by public policy. Even in the relatively few cases where the participating corporations were required to report on sustainability‐related information (i.e. financial and insurance companies), there was little indication that public policy was strongly considered in reporting. Although several participants felt that their sustainability reports could or should influence public policy, there were also indications that corporations are looking for additional guidance on reporting from government. In fact, the lack of direction from government was cited as a key barrier to improved linkages between corporate sustainability reporting and public policy. Future research should focus on addressing this problem, particularly at the individual sector level. Copyright © 2013 John Wiley & Sons, Ltd and ERP Environment
AlMe3‐Mediated Regio‐ and Chemoselective Reactions of Indole with Carbamoyl Electrophiles
Authors: Velavan A. , Sumathi S. , Balasubramanian K. K.
Published: April 2013

Herein, we report the regio‐ and chemoselective reactions of indole with carbamoyl electrophiles in presence of AlMe3. Indole‐3‐carboxamide was prepared in one‐step from a reaction of indole with tertiary carbamoylimidazole in the presence AlMe3. Under conditions for the formation of an aluminium ate complex, the reaction was diverted to the indole nitrogen. Secondary carbamoyl electrophiles in the presence of AlMe3 regiospecifically yielded trisubstituted ureas. The regiospecificity and chemoselectivity of the indole nitrogen towards ester and tertiary carbamoylimidazole functionalities were also studied.
Development of Amperometric Glucose Biosensor Based on Reconstitution of Glucose Oxidase on Polymeric 3‐Aminophenyl Boronic Acid Monolayer
Authors: Şenel Mehmet , Nergiz Cevdet , Dervisevic Muamer , Çevik Emre
Published: April 2013

An amperometric biosensor for determining glucose based on deflavination of the enzyme glucose oxidase and subsequent reconstitution of the apo‐protein with a complexed flavin adenine dinucleotide (FAD) monolayer is described. The GOx‐reconstituted electrode exhibited excellent electrocatalytic activities towards the reduction and oxidation of hydrogen peroxide as well. The prepared biosensor showed an excellent performance for glucose at +0.5 V with a high sensitivity (5.94 μA/mM) and relatively good response time (∼12 s) in a wide concentration range of 1–17 mM (correlation coefficient of 0.9998). The applicability to blood analysis was also evaluated.
Elimination half-life as a metric for the bioaccumulation potential of chemicals in aquatic and terrestrial food chains
Authors: Goss Kai-Uwe , Brown Trevor N. , Endo Satoshi
Published: April 2013

The assessment of chemicals as bioaccumulative in the regulatory process makes use of the bioconcentration factor as a metric. However, this metric does not account for the dietary uptake route and therefore cannot be applied to terrestrial food chains. In recent years, the biomagnification factor (BMF) and the trophic magnification factor (TMF) have been suggested as standard metrics for bioaccumulation. For regulatory purposes, though, the BMF and the TMF also suffer from a number of shortcomings. They are not applicable to assess uptake routes other than the diet (e.g., dermal uptake, as is important for personal care products). When measured in the field, they depend largely on biological and ecological factors and less so on the chemical's properties, and they are difficult to normalize and standardize. In the present study, the authors suggest the elimination half-life (EL0.5) of a chemical as an alternative metric for bioaccumulation. The EL0.5 is equivalent to the depuration rate constant (k2) that is measured in various bioaccumulation and bioconcentration tests. This metric can be applied to air- and water-breathing animals, and it is valuable for all uptake routes. It has a number of practical advantages over the BMF and the TMF. In combination with a standard uptake scenario, the EL0.5 can also be linked directly to a BMF threshold of unity. Thus, the EL0.5 as a bioaccumulation metric overcomes the shortcomings of the BMF and the TMF while still conserving the advantages of the latter metrics. Environ Toxicol Chem 2013;32:1663–1671. © 2013 SETAC
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

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 (>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

Urban 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

The 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

The 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

Analysis 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

The 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.
Analysis of tropical‐like cyclones over the Mediterranean Sea through a combined modeling and satellite approach
Authors: Miglietta M. M. , Laviola S. , Malvaldi A. , Conte D. , Levizzani V. , Price C.
Published: April 2013

Several Mediterranean vortices with characteristics similar to tropical cyclones are analyzed by means of numerical simulations, satellite products and lightning data. Numerical analysis suggests that the broad tropical‐like cyclone category includes in reality a set of different cyclones, ranging from very small and weak vortices to larger and stronger cyclones. One case displays a much longer persistence of tropical features than the other events. The analysis of the tracks identifies two preferred areas of occurrence: the Ionian sea and the Balearic Islands. The satellite analysis of cloud top height and retrieved rainfall indicates that the stage characterized by the most intense convective activity and rainfall anticipates the mature phase, when the cyclone is more intense and characterized by tropical features, during which convection is shallower and rainfall weaker. This result is confirmed by a preliminary analysis of the lightning activity.
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

To 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

Background

The incidence and risk factors of carotid artery stenosis in asymptomatic patients after head and neck radiation therapy (RT) are unknown.

Methods

This retrospective study reviewed asymptomatic patients treated with RT for head and neck cancer from 2000 to 2009 who underwent screening carotid ultrasound.

Results

Two 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).

Conclusion

Prevention 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
Imaging Mass Spectrometry Reveals Modified Forms of Histone H4 As New Biomarkers of Microvascular Invasion in Hepatocellular Carcinomas
Authors: Poté Nicolas , Alexandrov Theodore , Le Faouder Julie , Laouirem Samira , Léger Thibaut , Mebarki Mouniya , Belghiti Jacques , Camadro Jean-Michel , Bedossa Pierre , Paradis Valérie
Published: April 2013

Microvascular invasion (MiVI) is a major risk factor in postoperative tumor recurrence and mortality in hepatocellular carcinoma (HCC). Unfortunately, this histological feature is usually missed by liver biopsy because of limited sampling, and MiVI is commonly detected only after surgery and examination of the full resected specimen. To date, there exists no reliable tool for identifying MiVI prior to surgical procedures. This study aimed to compare the proteome of HCC with and without MiVI in order to identify surrogate biomarkers of MiVI. A training cohort comprising surgically resected primary HCC with MiVI (n = 30) and without MiVI (n = 26) was subjected to matrix-assisted laser desorption ionization imaging mass spectrometry (MALDI IMS). Comparative analysis of acquired mass spectra of the two groups yielded 30 differential protein peaks, among which 28 were more strongly expressed in HCC with MiVI. Among these, two peaks were identified as N-term acetylated histone H4 dimethylated at lysine (K) 20, and N-term acetylated histone H4 dimethylated at K20 and acetylated at K16. Both peaks were validated in the training cohort and in an independent validation cohort (n = 23) by immunohistochemistry and western blot. Conclusion: These results demonstrate the potential of MALDI IMS for uncovering new relevant biomarkers of MiVI in HCC, and highlight the role of epigenetic modifications in the prognosis of HCC. Preoperative detection of modified forms of histone H4 expression in tumor biopsies would be helpful in management of patients with HCC. (Hepatology 2013;53:983–994)
Species sensitivity distribution evaluation for chronic nickel toxicity to marine organisms
Authors: DeForest David K , Schlekat Christian E
Published: April 2013

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
Interstitial engraftment of adipose‐derived stem cells into an acellular dermal matrix results in improved inward angiogenesis and tissue incorporation
Authors: Komatsu Issei , Yang Jun , Zhang Ying , Levin L. Scott , Erdmann Detlev , Klitzman Bruce , Hollenbeck Scott T.
Published: April 2013

Acellular dermal matrices (ADM) are commonly used in reconstructive procedures and rely on host cell invasion to become incorporated into host tissues. We investigated different approaches to adipose‐derived stem cells (ASCs) engraftment into ADM to enhance this process. Lewis rat adipose‐derived stem cells were isolated and grafted (3.0 × 105 cells) to porcine ADM disks (1.5 mm thick × 6 mm diameter) using either passive onlay or interstitial injection seeding techniques. Following incubation, seeding efficiency and seeded cell viability were measured in vitro. In addition, Eighteen Lewis rats underwent subcutaneous placement of ADM disk either as control or seeded with PKH67 labeled ASCs. ADM disks were seeded with ASCs using either onlay or injection techniques. On day 7 and or 14, ADM disks were harvested and analyzed for host cell infiltration. Onlay and injection techniques resulted in unique seeding patterns; however cell seeding efficiency and cell viability were similar. In‐vivo studies showed significantly increased host cell infiltration towards the ASCs foci following injection seeding in comparison to control group (p < 0.05). Moreover, regional endothelial cell invasion was significantly greater in ASCs injected grafts in comparison to onlay seeding (p < 0.05). ADM can successfully be engrafted with ASCs. Interstitial engraftment of ASCs into ADM via injection enhances regional infiltration of host cells and angiogenesis, whereas onlay seeding showed relatively broad and superficial cell infiltration. These findings may be applied to improve the incorporation of avascular engineered constructs. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A:2939–2947, 2013.
Design features of implants for direct skeletal attachment of limb prostheses
Authors: Pitkin M.
Published: April 2013

In direct skeletal attachment (DSA) of limb prostheses, a construct is implanted into an amputee's residuum bone and protrudes out of the residuum's skin. This technology represents an alternative to traditional suspension of prostheses via various socket systems, with clear indications when the sockets cannot be properly fitted. Contemporary DSA was invented in the 1990s, and several implant systems have been introduced since then. The current review is intended to compare the design features of implants for DSA whose use in humans or in animal studies has been reported in the literature. © 2013 Wiley Periodicals, Inc. J Biomed Mater ResPart A: 101A: 3339–3348, 2013.
Modeling the microstructurally dependent mechanical properties of poly(ester‐urethane‐urea)s
Authors: Warren P. Daniel , Sycks Dalton G. , McGrath Dominic V. , Vande Geest Jonathan P.
Published: April 2013

Poly(ester‐urethane‐urea) (PEUU) is one of many synthetic biodegradable elastomers under scrutiny for biomedical and soft tissue applications. The goal of this study was to investigate the effect of the experimental parameters on mechanical properties of PEUUs following exposure to different degrading environments, similar to that of the human body, using linear regression, producing one predictive model. The model utilizes two independent variables of poly(caprolactone) (PCL) type and copolymer crystallinity to predict the dependent variable of maximum tangential modulus (MTM). Results indicate that comparisons between PCLs at different degradation states are statistically different (p < 0.0003), while the difference between experimental and predicted average MTM is statistically negligible (p < 0.02). The linear correlation between experimental and predicted MTM values is R2 = 0.75. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A: 3382–3387, 2013.
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

This 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

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 < 0.05). Also, Asians had 9% smaller Tt.Ar and 27% greater Ct.Th (p < 0.01). In females, Asians had smaller Tt.Ar than whites (16%, p < 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 < 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

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

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

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.
Computational Study of Cage Like (ZnO)12 Cluster Using Hybrid and Hybrid Meta Functionals
Authors: Flores‐Hidalgo Manuel Alberto , Glossman‐Mitnik Daniel , Galvan D. H. , Barraza‐Jimenez Diana
Published: April 2013

Density Functional Theory employing hybrid and M06 functionals in combination with three different basis sets is used to calculate the ground state of a cage like (ZnO)12 nanocluster which has been consistently reported as the more stable cluster for its particular size. B3LYP and B3PW91 hybrid functionals combined with 6‐31+G*, Lanl2dz and SDD basis sets are employed to treat the ZnO molecular system. Alternatively, three M06 functionals in combination with three basis sets are employed in the nanostructure calculations. Results obtained by treating ZnO sodalite cage nanocluster with M06 functionals demonstrated comparable quality to results obtained with hybrid functionals. Within this study, efficient theoretical DFT methods with the widely known hybrid and the recently created M06 meta‐hybrid functionals are employed to study nanostructured ZnO. Our resulting parameters provide a fresh approach performance wise on the different theoretical methods to treat transition metal nanostructures, particularly, ZnO nanoclusters geometry and electronic structure.
Rapid Preparation of Monolithic Molecular Imprinted Polymer Fiber for Solid Phase Microextraction by Microwave Irradiation
Authors: Jin Ya‐Feng , Chen Na , Liu Run‐Qiang , Zhang Yu‐Ping , Bai Lian‐Yang , Chen Jun
Published: April 2013

In this paper, a simple, fast and in situ polymerization strategy to prepare monolithic molecularly imprinted polymer (MIP) fibers for solid phase microextraction (SPME) is developed using silica capillaries as molds. With the help of microwave irradiation, polymerization was carried out in 5.5 min using olivetol as a template molecular, α‐methacrylic acid (MAA) as a functional monomer and ethylene dimethacrylate (EDMA) as a crosslinker, toluene and dodecanol as the binary porgens. The resulted MIP fibers were finally obtained after silica being etched away with a controlled length, and subsequently characterized by scanning electron microscope (SEM) and Fourier transform infrared absorption spectroscopy (FT‐IR). Under the optimal extraction conditions, a simple method based on the coupling of MIP SPME with high performance liquid chromatography (HPLC) was used for the selective determination of the model mixtures of olivetol, phenol and m‐toluidine in lake water and wheat bran samples. The recoveries of olivetol, phenol and m‐toluidine for both samples were in the range of 87.3‐93.6%, 21.4‐27.2%, 18.9‐24.8% at three spiked levels, respectively, demonstrating that higher extraction and the specific absorption occurred between the template molecule and the prepared MIP fiber.
NaBH4/DOWEX(R)50WX4: A Convenient Reducing System for Fast and Efficient Reduction of Carbonyl Compounds to Their Corresponding Alcohols
Authors: Setamdideh Davood , Karimi Zahra , Alipouramjad Avat
Published: April 2013

The reduction of a variety of carbonyl compounds was efficiently carried out with NaBH4/DOWEX(R)50WX4 system. The reactions were performed to give the corresponding alcohols derivatives in perfect yields in THF at room temperature. Reduction of acyloins and a‐diketones by this reducing system produced efficiently the corresponding vicinal diols. Also, the reduction of aldehydes over ketones has been accomplished successfully by this system. Regioselectivity of this system was also investigated with exclusive 1,2‐reduction of conjugated carbonyl compounds to their corresponding allylic alcohols in high to excellent yields.
A strategy for efficient immobilization of laccase and horseradish peroxidase on single‐walled carbon nanotubes
Authors: Li Ying , Huang Xirong , Qu Yinbo
Published: April 2013

BACKGROUND

The immobilization of biomacromolecules on carbon nanotubes has attracted considerable attention. Based on the specific affinity between concanavalin A (Con A) and glycosyl, and the ability of alkyl polyglucoside to disperse single‐walled carbon nanotubes (SWNTs), a new self‐assembly immobilization strategy is developed.

RESULTS

Using laccase (Lac) and horseradish peroxidase (HRP) as models, it is demonstrated that this new self‐assembly immobilization strategy has obvious advantages over the direct adsorption immobilization strategy in enzyme loadings ( 1.34‐fold (Lac) and 1.46‐fold (HRP) higher) and in the specific activity ( 5.06‐fold (Lac) and 4.77‐fold (HRP) higher). Circular dichroism (CD) spectra and fluorescence spectra also indicate that the present new indirect immobilization strategy has less impact on the enzyme conformation compared with the direct adsorption strategy. For the catalytic oxidation of dibenzothiophene (DBT), the immobilized HRP prepared using the present self‐assembly strategy was more effective than that using the direct adsorption strategy.

CONCLUSION

Based on these findings, it is concluded that the present self‐assembly strategy can greatly improve the enzymatic properties of the immobilized enzymes. © 2013 Society of Chemical Industry