bluuebunny/crossref_metadata_2025 huggingface dataset:
Production of the Bacillus licheniformis SubC protease using Lactococcus lactis NICE expression system
Authors: Mirończuk Aleksandra M , Krasowska Anna , Murzyn Anna , Płachetka Małgorzata , Łukaszewicz Marcin
Published: November 2012

In this work the subC gene from Bacillus licheniformis encoding subtilisin was cloned into the nisin-controlled expression (NICE) vectors (pNZ8048 and pNZ8148) with or without the signal peptide SP Usp45 directing extracellular secretion via Sec machinery. Extracellular protease production and activity was tested using Lactococcus lactis NZ9000 as host, which could be used for rennet production. The efficiency of protein production was tested using purified nisin and the supernatant of L. lactis NZ970 nisin producer. Similar results were obtained for 1 ng/ml nisin and 10 000 diluted supernatant. SP Usp45 signal peptide effectively directed extracellular localization of active and stable protease. SubC signal for extracellular localization in B. licheniformis, was also recognized by L. lactis Sec pathway, although with lower efficiency, as shown by a 3-fold lower protease activity in the medium. Protease production and activity was optimized using parameters such as induction time, nutrients (glucose, casitone) supplementation during growth or protease stabilization by calcium ions. The results were also verified in fed-batch bioreactor for further scale-up of the expression system.
Alteration of non-protein respiratory quotient after hepatocellular carcinoma treatment can be related to des-γ-carboxy prothrombin before treatment
Authors: Saito Masaya , Seo Yasushi , Yano Yoshihiko , Miki Akira , Momose Kenji , Hirano Hirotaka , Yoshida Masaru , Azuma Takeshi
Published: November 2012

Background

Transcatheter arterial chemoembolization (TACE) is an effective treatment for hepatocellular carcinoma (HCC) that would occasionally lead to energy malnutrition through therapeutic hypoxic stress. We aimed to clarify the correlation between the energy malnutrition after TACE and low tolerability for hypoxia of non-tumoral liver before TACE.

Findings

We performed a prospective cohort study involving 100 HCC patients who underwent TACE at Kobe University Hospital. Indirect calorimetry was performed before and 7 days after TACE, and non-protein respiratory quotient (npRQ) as an indicator of the energy malnutrition was measured. Blood biochemical examinations were also performed before TACE. As an indicator of hypoxic marker, des-γ-carboxy prothrombin (DCP) was measured before TACE. The correlation between npRQ ratio (7 days after/before TACE) and DCP (before TACE) was statistically examined. Spearman’s correlation coefficient test showed that npRQ ratio (Day 7/Day 0) was significantly related to DCP (Day 0) (p=0.0481, r=-0.2033). On the other hand, npRQ ratio (Day 7/Day 0) was not related to alpha fetoprotein (Day 0) (p=0.6254, r=-0.0494).

Conclusions

The npRQ reduction after TACE was related to a high value of DCP before TACE. The energy malnutrition after TACE would originate from low tolerability for hypoxia of non-tumoral liver. The HCC patients with a high value of DCP before TACE would clinically have a high risk of the energy malnutrition after TACE.
Using Large Driving Record Samples and a Stochastic Approach for Real-World Driving Cycle Construction: Winnipeg Driving Cycle
Authors: Ashtari Ali , Bibeau Eric , Shahidinejad Soheil
Published: November 2012

The challenges in the development of plug-in electric vehicle (PEV) powertrains are efficient energy management and optimum energy storage, for which the role of driving cycles that represent driver behaviour is instrumental. Discrepancies between standard driving cycles and real driving behaviour stem from insufficient data collection, inaccurate cycle construction methodology, and variations because of geography. In this study, we tackle the first issue by using the collected data from real-world driving of a fleet of 76 cars for more than one year in the city of Winnipeg (Canada), representing more than 44 million data points. The second issue is addressed by a proposed novel stochastic driving cycle construction method. The third issue limits the results to mainly Winnipeg and cities that have similar features, but the methodology can be used anywhere. The methodology develops the driving cycle using snippets extracted from recorded time-stamped speed of the vehicles from the collected database. The proposed Winnipeg Driving Cycle (WPG01) characteristics are compared to eight existing standard driving cycles and are more able to represent aggressive driving, which is critical in PEV design. An attempt is made to isolate how many differences could be attributed to the sample size and the methodology. The proposed construction methodology is flexible to be optimized for any selection of driving parameters and thus can be a recommended approach to develop driving cycles for any drive train topology, including internal combustion engine vehicles, hybrid vehicles, plug-in hybrid, and battery electric vehicles. Characterization of vehicle parking durations and types of parking (home, work, shopping), critical for duty cycles for PEV powertrains, are reported elsewhere. Here, the focus is on the mathematical approach to develop a drive cycle when a large database with high resolution of driving data is available.
Eine Bezeichnung für libysche Warlords?
Authors: Römer Malte
Published: November 2012

The title aA n xrw, borne by Libyans, is mainly known from hieroglyphic inscriptions. In this article, additional evidence from papyri of the ThirdIntermediate Period is presented, which has been unnoticed or misunderstood until now.

The meaning of this title is problematic. The previously suggested translation as “Great one of the enemies” does not explain its adoption by those enemies in question, namely the Libyans, for their own nobles. Therefore a different meaning is suggested.
EIS studies of anodic aluminum oxide films
Authors: Linardi Evelina M. , Lanzani Liliana A. , Collet Lacoste Juan R.
Published: November 2012

Samples of AA 6061 alloy and Al 5N were anodized at constant potential conditions and sealed in distilled boiling water. Immersion tests in high purity water were also carried out on AA 6061 samples at open circuit potential. EIS measurements were then performed in order to investigate the properties of the oxides obtained.

For sealed anodic oxides on AA 6061 and Al 5N, EIS experimental data was useful to differentiate between the capacitances of the two layers present in the oxide, named the barrier and porous layers. EIS data obtained for oxide layers grown at open circuit potential in AA 6061 allowed estimating the capacitance of the barrier layer, which value was greater than the barrier layer capacitance present in anodic oxides.
Characterisation of concrete, mortar and calcium silicate hydrated phases (CSH) and thorium retention analyses by ion beam techniques.
Authors: Alonso Ursula , Missana Tiziana , Garcia-Gutierrez Miguel , Rojo Henar , Patelli Alessandro , Rigato Valentino , Ceccato Daniele
Published: November 2012

Cement-based materials, like concrete and mortar, are widely used in radioactive waste repositories. A deep characterization of these heterogeneous materials, and of their main phases, is necessary to evaluate their capability of retaining critical radionuclides (RN).

In this study, the ion beam technique micro- Particle Induced X- Ray Emission (μPIXE) is used to characterize the concrete and mortar used in the Spanish low level waste repository. Two calcium silicate hydrate (CSH) phases with different Ca/Si ratio are also studied, because they are known to be amongst the most relevant phases, formed upon cement hydration, that retain RN. The retention of thorium on the above mention materials, as relevant tetravalent actinide, is also analyzed. Results are compared with Scanning Electron Microscopy- Energy Dispersive X-Ray Spectroscopy (SEM-EDX) analyses.
Corrosion of Steel Drums Containing Cemented Ion-Exchange Resins as Intermediate Level Nuclear Waste
Authors: Duffó Gustavo S. , Farina Silvia B. , Schulz Fátima M.
Published: November 2012

Ion-exchange resins are used for purification of radioactive liquid waste from nuclear reactors. After exhaustion, resins become intermediate level radioactive waste to be managed. They have to be immobilized before being stored to improve the leach resistance of the waste matrix and to maintain mechanical stability for safety requirements. The immobilized resins are thus contained in steel drums that can undergo internal corrosion depending on the presence of certain contaminants. This work shows an study of the corrosion susceptibility of steel drums in contact with cemented ion-exchange resins with different types and contents of aggressive species. Results show that the corrosion depth of the steel drums after a period of 300 years (foreseen life-span of the radioactive waste disposal facility), in the most unfavorable case (high chloride contamination), will be considerably lower than the thickness of the wall of the drums.
Long-Term Corrosion of 2,000-Year-Old Ancient Iron Sword
Authors: Mitsui Seiichiro , Fujii Atsuhiro , Higuchi Megumi , Nishimura Kohsuke
Published: November 2012

An ancient iron sword (ca 2,000 year old) excavated from Ohtake-nishi archaeological site in Osaka Prefecture, is one of the oldest cast iron swords in Japan. Because of a good state of preservation, such as the sharply-defined “Shinogi” (the longitudinal ridge) on the surface, we studied relationship between the burial environment and corrosion behavior. As environmental conditions, we investigated groundwater chemistry and corrosion rate with iron probe monitor, etc. Regarding corrosion state, we analyzed corrosion depths with an X-ray computed tomography and corrosion products with a portable X-ray diffractometer equipped with X-ray fluorescence spectrometer. As results, we found that the redox potential and dissolved oxygen level as environmental conditions were very low, and that the corrosion rate (7.5×10-4 mm/y) evaluated from measured corrosion depths was smaller than the probe corrosion rate (3.2–5.2×10-2 mm/y) by two orders of magnitude. The results suggested that the corrosion layer of siderite formed on the iron sword surface inhibited corrosion reaction.
Radiation Damage of II, III, IV, V Pyrochlores - CaLnZrNbO7
Authors: Whittle Karl R. , de los Reyes Massey , Gao Yan , Blackford Mark G. , Zaluzec Nestor J. , Lumpkin Gregory R.
Published: November 2012

Pyrochlores based on the general composition CaLnZrNbO7 (where Ln = La, Nd, Sm, Gd and Ho) have been prepared, and irradiated through the crystalline-amorphous transition, with 1 MeV Kr ions at the IVEM-TANDEM user facility. The obtained critical temperatures show a decrease from La to Gd (∼680 K to ∼230 K), with Ho being resistant to amorphisation at 50K. The results suggest that the amorphisation cross section for these materials is directly related to the Ln component.
Dyes in Vertically Aligned Carbon Nanotube Arrays for Solar Cell Applications
Authors: Lackner Gerhard , Endler Ingolf , Meissner Frank , Scholz Sebastian , Mayer-Uhma Tobias , Liebschner Rocco , Bezugly Viktor , Meiss Jan , Mkandawire Martin , Boucher Richard , Michaelis Alexander , Lupascu Doru C.
Published: November 2012

The infiltration of dissolved dyes into vertically aligned carbon nanotube arrays (va-CNT) is reported. The ultra hydrophobic surface of the CNT forest can be wetted and hence infiltrated for an appropriate choice of solvent. The dye-infiltrated CNT array forms a well ordered bulk-heterojunction structure for organic solar cells in which the CNT can act as a large electrode or, for appropriate energy levels, as an acceptor material. Derivatives of the small molecule copper phthalocyanine or the polymer poly(3-hexylthiophene) were used as dyes. Drop coating was chosen as the infiltration technique resulting in a completely embedded CNT forest. Field emission secondary electron microscopy analysis illustrates the final layer quality. Common electrical characterization under AM1.5 illumination proves photosensitivity and implies photovoltaic behavior of the composite.
Effect of Cathode Metal Evaporation Rate on the Deep Trapped Hole Formation in Bulk Heterojunction Organic Solar Cells
Authors: Yengel Emre , Islam M. Saif
Published: November 2012

In bulk heterojunction organic solar cells, open-circuit voltage (Voc) is mainly dependent on the lowest unoccupied molecular orbital and the highest occupied molecular orbital of the donor/acceptor polymer pair in the active layer. However, there are other factors that contribute to considerable reduction in the Voc. The active layer/cathode interface is one of these factors. Previous studies show that e-beam evaporation of the cathode metal contact forms deep interface trap holes in the active layer which increases the Voc of the solar cells. Although these studies show the effect of deeply trapped holes on the Voc, several attempts to elucidate the mechanism behind this effect revealed their subtle and elusive nature. In this work, the effect of cathode contact annealing rate on the overall efficiency is studied. Three different sets of devices were fabricated with varying cathode evaporation rates of 0.1Å/s, 1Å/s and 5Å/s. The results show that at low evaporation rates, atoms in the cathode materials lack adequate energy to form deeply trapped holes. Additionally, above a certain value, the evaporation rate does not have a significant effect on the formation of deeply trapped holes. We also demonstrate that power conversion efficiencies of the devices can be maximized by maintaining the evaporation rate within a specific range.
Cytotoxic and Anti-cancer Effects of Nickel Nanowires against Pancreatic Cancer Cells
Authors: Hossain Md. Zakir , Khudhayer Wisam J. , Akter Rozina , Karabacak Tansel , Kleve Maurice G.
Published: November 2012

Cytotoxicity study of magnetic nanomaterials is a key consideration for biomedical applications. Very little is known about the cytotoxic and anti-cancer effects of nickel nanowires (Ni NWs) on mammalian cells and their interaction with proliferating cancer cells. Current therapeutics do not address the full heterogeneity of pancreatic cancers due to the resistance to apoptosis and does not suffice for a successful treatment. Therefore, synthesis of novel anticancer drugs continues to be a potential topic for pancreatic cancer research. In this study, we have investigated the cellular toxicity and anti-cancer effects of Ni NWs in one of the most aggressive human pancreatic ductal cancer (Panc-1) cell lines with the objective of development of a potential treatment strategy. Ni NWs were fabricated in a custom-made setup utilizing the electrodeposition method. Elemental analysis, crystallographic structure, and morphological properties of the synthesized Ni NWs were investigated using Energy Dispersive X-ray Analysis (EDAX), X-Ray Diffraction (X-RD) and Scanning Electron Microscopy (SEM), respectively. Panc-1 cell cultures were maintained according to a slightly modified American Type Culture Collection (ATCC) protocol. Morphological apoptogenic characteristics assessment of the Ni NWs induced Panc-1 cell was accomplished using phase contrast microscopy (PCM). Two commercially available cytotoxicity procedures including 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) and trypan blue (TB) assays were utilized to determine the qualitative and quantitative cytotoxicity and anti-cancer effects of Ni NWs. As a negative control, Panc-1 cells without Ni NWs treatment were used in all experiments. Phase contrast microscopy (PCM) was used to confirm the Ni NWs internalization by Panc-1 cells. Both the MTT and TB assays, qualitatively and quantitatively confirmed the cytotoxic and anti-cancer effects of Ni NWs treated Panc-1 cells in vitro in both concentration and exposure-time dependent manners. We studied the cytotoxic and anti-cancer effects of Ni NWs on Panc-1 cells using novel integrated bionanotechnological approaches to understand the corresponding biological pathway with the objective of developing pancreatic cancer treatment. More specifically, we explored the molecular mechanisms associated with the pathway involved in Ni NWs induced toxicity against Panc-1 cells. Our results demonstrated that Ni NWs show strong candidacy for targeting cell selective applications in pancreatic cancer therapy. Key words: Nickel Nanowires, anti-cancer effects, pancreatic cancer.
Thermal Gelation and Stability of Pectin Grafted with PEPE
Authors: Santan Harshal D. , Neffe Axel T. , Kamlage Stefan , Lendlein Andreas
Published: November 2012

Stimuli-sensitive materials can change properties upon exposure to an external stimulus. Thermoreversible gelation upon heating is one example for such a stimuli sensitivity. Here, it is of significance to tailor the transition temperature and to achieve large changes of G’ and the viscosity. Grafting of the thermosensitive poly(ethylene glycol-b-propylene glycol-b-ethylene glycol)s (PEPEs) to pectin was performed in order to investigate if tailoring of the sol-gel-transition temperature can be achieved by adjusting the grafting ratio. PEPEs were aminated and grafted to the polysaccharide via EDC coupling as shown by FTIR. The sol-gel transition of the pectin, PEPE, and the grafted system (PGP) was investigated by rheology. The gelation temperature (Tgel) of the system could be adjusted by varying the grafting density of PEPE onto pectin as well as by the concentration of the thermosensitive polymer in aqueous solution. A concentration of 15 – 20 wt% of the grafted system in water led to gelation temperatures in the range of 25 – 33 °C and the critical micelle concentration (CMC) and critical micelle temperature (CMT) of the grafted systems were determined by UV spectroscopy. The viscosity and the G’ increased by four orders of magnitudes at Tgel, which is comparable to PEPEs alone, but could be reached at lower PEPE concentrations. In the future, a thorough mechanistic investigation of the gelation process would be of interest.
Tribological Properties of Graphene and Boron-Nitride Layers: A Fully Atomistic Molecular Dynamics Study
Authors: dos Santos Ricardo P. , Machado Leonardo D. , Legoas Sergio B. , Galvao Douglas S.
Published: November 2012

Graphene has been one of the most important subjects in materials science in the last years. Recently, the frictional characteristics of atomically thin sheets were experimentally investigated using atomic force microscopy (AFM). A new mechanism to explain the enhanced friction for these materials, based on elastic compliance has been proposed. Here, we have investigated the tribological properties of graphene and boron-nitride (single and multi-layers) membranes using fully atomistic molecular dynamics simulations. These simulations were carried out using classical force fields, as implemented in the Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) code. The used structural models contain typically hundreds of thousands of atoms. In order to mimic the experimental conditions, an artificial AFM tip was moved over the membranes and the tribological characteristics determined in terms of forces and energies. Our results are in good agreement with the available experimental data. They show that the observed enhanced tribological properties can be explained in terms of out-of-plane geometrical distortions and elastic waves propagation. They validate the general features of the model proposed by Lee et al. (Science 328, 76 (2010).
Diffusion-bonded CNT carpets for fundamental CDI studies
Authors: Enright R. , Mitchell R. , Mutha H. , Lv C. , Christiansen M. , Thompson C. V. , Wang E. N.
Published: November 2012

Uncertainty about future energy and water supplies suggests a pressing need to develop efficient technologies for water desalination. Capacitive deionization (CDI), a method that captures ions in the electrical double layer (EDL) of an electrochemical capacitor, is a promising technology that can potentially fulfill those requirements. Similar to supercapacitors, ideal CDI electrodes should have a large electrolyte-accessible specific surface area available for ion adsorption with rapid charging/discharging characteristics. Unlike supercapacitors, CDI electrodes are required to operate in aqueous electrolytes with low ionic concentrations in a non-linear charging regime. To explore this practically and theoretically important regime, we developed robust, electrochemically-compatible carbon nanotube (CNT) carpet electrodes that posses a well-defined and uniform pore structure that is more readily analyzed in comparison to the random and multi-scale pore structure of typical carbon electrodes. The fabricated electrodes were characterized using cyclic voltammetry and potentiostatic charging in aqueous NaCl solutions (no = 20 - 90 mM) using a three electrode setup. Examination of the CV and potentiostatically-measured capacitances were consistent with EDL behavior dictated by the Stern layer. However, some deviations from the expected behavior were observed with increasing salt concentration during potentiostatic testing.
Probing strain and microstrain in nanostructured thin layers.
Authors: Baldinozzi Gianguido , Simeone David , Gosset Dominique , Bérar Jean-Francois
Published: November 2012

The analysis of the structures and microstructures of nanostructured thin layers can be performed using laboratory grazing incidence diffraction, provided accurate corrections are performed to handle the instrumental broadening effects related to the experiment geometry for an impinging beam close to the critical angle. Implementing these corrections in Rietveld refinement software allows the accurate extraction of quantitative relevant information about the structure (strain and atomic positions) and the microstructure (crystallite size and microstrain), selectively probing the material on a depth of few nanometers.
Morphology and Crystallinity Control of Novel Spider Silk-like Block Copolymer
Authors: Huang Wenwen , Krishnaji Sreevidhya , Kaplan David , Cebe Peggy
Published: November 2012

A new family of A-B di-block copolymers based on the amino acid sequences of Nephila clavipes major ampulate dragline spider silk, which have a strong potential for applications in tissue regeneration and drug delivery, was synthesized and characterized. The morphology was assessed by SEM: HBA3 formed fibrillar structure and 2 μm diameter hollow micelles, while HBA4 and HBA6 formed hollow micelles in water solution. The secondary structures of water-cast spider silk-like block copolymer films were assessed by FTIR. The crystallinity was determined by Fourier self-deconvolution of the amide I spectra and confirmed by wide angle X-ray diffraction. Results indicate that the self-assembled morphology and the crystallinity can be varied by changing the length of A-block, and a minimum of 3 A-blocks are required to form β sheet crystalline regions in water-cast spider silk block copolymers. A theoretical model was used to predict the specific reversing heat capacity, Cp(T), which is crucial to the design of smart biomaterials. Excellent agreement was found between the theoretical value and the Cp(T) determined by temperature modulated differential scanning calorimetry. This method can serve as a standard by which to assess the thermal properties for other biologically inspired block copolymers, and then be further applied to control the biological interactions for use in drug delivery and smart biomaterials applications.
Biomimetic Mineral-Protein Composites formed by an Automated Alternate Soaking Process
Authors: Armitage Oliver E. , Strange Daniel G.T. , Oyen Michelle L.
Published: November 2012

Biomineralized composite materials found in nature have a compromise of good mechanical properties and relatively small embodied energies in the process of their formation. The Alternate Soaking Process (ASP) is a laboratory technique that has only recently been applied to replicating composite biomineralization. The nexus of the ASP – heterogeneous nucleation – makes it ideal for replicating biominerals where the mineral is templated onto an organic substrate, such as occurs in avian eggshell. Here we demonstrate the deposition of a calcium carbonate gelatin composite on either glass cover slips or demineralized eggshell membranes using an automated ASP. SEM images and FTIR spectra of the resulting mineral show that by altering the amount of gelatin in the growth solutions the final organic component can be controlled accurately in the range of 1-10%, similar to that of natural eggshell. This study shows for the first time the co-precipitation of a CaCO3 – gelatin composite by an ASP and that the organic fraction of this mineral can be tuned to mimic that of natural biomineralized composites.
MMSSC Chemotaxis near Porous Surface of Biocompatible NiTi Scaffolds Synthesized by Selective Laser Sintering (SLS)
Authors: Shishkovsky Igor V. , Volchkov Stanislav E. , Tumina Olga V.
Published: November 2012

Multipotential mesenchymal stromal stem cells (MMSSC) are an excellent model for testing of the toxicity and biocompatibility of natural-tissue-engineering scaffolds (extracellular matrix). Such studies allow prediction of the behavior of implanted materials in the human. In the present work, testing of a three-dimensional prototype of a smart material – nitinol (the intermetallic phase NiTi) – to evaluate chemotaxis and biocompatibility was conducted.

Porous samples were synthesized by the selective laser sintering (SLS) method, establishing different surface conditions in the samples. The surface microstructure and roughness were observed by scanning electron microscopy (SEM) and optical microscopy. The results revealed the clear influence of the surface roughness on stem cell proliferation, morphology, and adhesion. The NiTi samples were well tolerated by the cells but the number of focal contacts decreased with increasing porosity. The proliferation speed was 0.694 doubling/day in the control group and 0.532 doubling/day for the NiTi group. Whereas the control group showed immature and actively divided stem cells, cell growth to enormous sizes (i.e., rapid aging) and a fall in fission activity in the proximity of an external irritant (viz., the NiTi scaffold) was observed.
Numerical Simulation of SOFC Electrode Polarization Using Three-Dimensional Microstructure Reconstructed by FIB-SEM
Authors: Shikazono Naoki , Kasagi Nobuhide
Published: November 2012

Three-dimensional numerical simulations can provide information which cannot be obtained from experiments and can be a powerful tool for investigating reaction phenomena in solid oxide fuel cell (SOFC) electrodes. In the present study, a dual-beam focused ion beamscanning electron microscope is used to reconstruct the three dimensional microstructures of the SOFC electrodes, and their polarization characteristics are predicted by a lattice Boltzmann method. Predicted overpotentials for Ni-YSZ anode and mixed ionic and electronic conducting cathode (La0.6Sr0.4Co0.2Fe0.8O3-δ; LSCF6428) are compared with the experimental data for validation. In addition, three-dimensional distributions of electrochemical potential and current densities inside the electrode microstructures are obtained. Large non-uniformities of potential and current distributions are found in the Ni-YSZ anode, while those became much uniform in the LSCF cathode. The present method can be expected as a powerful tool for investigating local potential fields which affect local reactions and diffusion processes as well as local physical properties of the SOFC electrodes.
Effect of nanosilica and silica fume content on the bond properties of macro-synthetic fibre in cement-based composites
Authors: Park Chang-Gi , Lee Jeong-Woo
Published: November 2012

In this study, the effects of nanosilica and silica fume content on the bond properties of macro-synthetic fibre in cement-based composites were investigated. The pullout behaviour of macro-synthetic fibre was evaluated by performing dog-bone bond tests according to JCI SF-8 at nanosilica and silica fume replacement ratios of 0, 2, 4, 6 and 8% based on cement weight. The addition of nanosilica and silica fume had a significant effect on the bond properties of macro-synthetic fibre. Specifically, the addition of 0∼2% nanosilica enhanced pullout behaviour, bond strength and interface toughness, whereas 4% or more nanosilica reduced pullout behaviour, bond strength and interface toughness. For silica fume, pullout load-to-displacement behaviour, bond strength and interface toughness increased in the range of 0 to 8%. These results demonstrate that the presence of nanosilica and silica fume strengthen the fibre–matrix interface of macro-synthetic fibre in cement-based composites by filling voids in the interface region. The relative bond strength and interface toughness were also analysed, except for compressive strength, to evaluate the bond properties of macro-synthetic fibre in cement-based composites at various nanosilica and silica fume replacement ratios. The ratios of nanosilica and silica fume had a significant effect on bond properties, regardless of the compressive strength of the cement-based composites. Microstructural analysis of macro-synthetic fibre after pullout tests showed scratches due to friction.
Exploring the ecological processes driving geographical patterns of breeding bird richness in British Columbia, Canada
Authors: Fitterer Jessica L. , Nelson Trisalyn A. , Coops Nicholas C. , Wulder Michael A. , Mahony Nancy A.
Published: November 2012

British Columbia (BC), Canada, has a diverse landscape that provides breeding habitat for >300 avian species, and the recent development of the BC Breeding Bird Atlas data set presents key information for exploring the landscape conditions which lead to biological richness. We used the volunteer‐collected raw breeding bird evidence data set to analyze the effects of sampling biases on spatial distribution of observed breeding bird species and implemented regression tree analysis (Random Forests) to examine the influence of productivity, ambient energy, and habitat heterogeneity on independently measured breeding bird richness. Results indicated that total breeding species richness is correlated with total survey effort (α < 0.001). By stratifying species richness by survey effort, we observed that ambient energy is the top‐ranked environmental predictor of breeding bird richness across BC, which, when used in combination with a number of other environmental variables, explains ∼40% of the variation in richness. Using our modeled relationships, we predicted breeding bird species richness in the areas of BC not presently surveyed between three and six hours. The majority of the productive Boreal Plains, the southern portion of the Taiga Plains region, the lowlands of the Southern and Central Interior, along the Rocky Mountain Trench, and the coastal areas of the Georgia Depression are predicted to have the highest categories of breeding richness (35–57 unique species). Our results support ongoing species diversity gradient research, which identifies ambient energy as an important factor influencing species diversity distributions in the Northern Hemisphere. By linking breeding bird richness to environmental data derived from remotely sensed data and systematically collected climate data, we demonstrate the potential to monitor shifts in ambient energy as a surrogate for vertebrate habitat condition affecting population levels. By analyzing the influence of survey effort on species richness metrics, we also highlight the need to consider adding attributes to the raw breeding bird data set to describe observer experience, such as hours or seasons spent surveying, and provide survey dates to allow greater flexibility for removing survey bias. These additions can increase the utility of atlas data for species richness studies useful for conservation planning.
Divergent carbon dynamics under climate change in forests with diverse soils, tree species, and land use histories
Authors: Scheller Robert M. , Kretchun Alec M. , Van Tuyl Steve , Clark Kenneth L. , Lucash Melissa S. , Hom John
Published: November 2012

Accounting for both climate change and natural disturbances—which typically result in greenhouse gas emissions—is necessary to begin managing forest carbon sequestration. Gaining a complete understanding of forest carbon dynamics is, however, challenging in systems characterized by historic over‐utilization, diverse soils and tree species, and frequent disturbance. In order to elucidate the cascading effects of potential climate change on such systems, we projected forest carbon dynamics, including soil carbon changes, and shifts in tree species composition as a consequence of wildfires and climate change in the New Jersey pine barrens (NJPB) over the next 100 years. To do so, we used the LANDIS‐II succession and disturbance model combined with the CENTURY soil model. The model was calibrated and validated using data from three eddy flux towers and the available empirical or literature data. Our results suggest that climate change will not appreciably increase fire sizes and intensity. The recovery of C stocks following substantial disturbances at the turn of the 20th century will play a limited but important role in this system. In areas characterized by high soil water holding capacity, reduced soil moisture may lead to lower total C and these forests may switch from being carbon sinks to becoming carbon neutral towards the latter part of the 21st century. In contrast, other areas characterized by lower soil water holding capacity and drought tolerant species are projected to experience relatively little change over the next 100 years. Across all soil types, however, the regeneration of many key tree species may decline leading to longer‐term (beyond 2100) risks to forest C. These divergent responses were largely a function of the dominant tree species, and their respective temperature and soil moisture tolerances, and soil water holding capacity. In summary, the system is initially C conservative but by the end of the 21st century, there is increasing risk of de‐stabilization due to declining growth and regeneration.
Prevalence of Chlamydia trachomatis, Mycoplasma hominis, Mycoplasma genitalium, and Ureaplasma urealyticum Infections and Seminal Quality in Infertile and Fertile Men in Kuwait
Authors: Al‐Sweih Noura A. , Al‐Fadli Amani H. , Omu Alexander E. , Rotimi Vincent O.
Published: November 2012

Abstract: This study was undertaken to determine the prevalence of Chlamydia trachomatis, mycoplasmas, and ureaplasmas in semen samples of infertile compared with fertile men and to evaluate the seminological variables of semen from infected and noninfected men. A total of 127 infertile and 188 fertile men seen in a maternity hospital clinic were recruited into the study over a period of 14 months. Specimens were obtained by masturbation and examined for the presence of Ureaplasma urealyticum, Mycoplasma hominis, Mycoplasma genitalium, and C trachomatis by polymerase chain reaction. Semen analysis was performed according to World Health Organization guidelines. U urealyticum, M hominis, M genitalium, and C trachomatis were demonstrated in the semen samples of 31 (24.4%) vs 49 (26.1%), 22 (17.1%) vs 61 (32.4%), 6 (4.7%) vs 6 (3.2%), and 5 (3.9%) vs 7 (3.7%), respectively, of infertile and control men. Mixed infections were detected in 14 (11%) of infertile and 29 (15.4%) of fertile men. The infertile men positive for M hominis had semen samples that showed statistically significant differences in the mean of sperm pH and leukocyte count between infected and uninfected men (P < .03 and P < .001, respectively). Similarly, there was statistically significant difference in the leukocyte counts of M genitalium and C trachomatis in infected compared with uninfected men. A similar trend was noted in infected fertile compared with uninfected men. The difference in prevalence of these urogenital pathogens among infertile compared with fertile men was not statistically significant. However, genital mycoplasmas and chlamydial infections appeared to influence semen quality negatively.
Acute Effects of Sildenafil on Uroflowmetric Parameters in Erectile Dysfunction Patients With and Without Lower Urinary Tract Symptoms
Authors: Öztürk Metin İ. , Koca Orhan , Sertkaya Zülfü , Keleş Muzaffer O. , Kaya Cevdet , Karaman Muhammet I.
Published: November 2012

Abstract: Using phosphodiesterase type 5 (PDE5) inhibitors in patients with lower urinary tract symptoms continues to draw attention. Despite clinical improvements in patients, it is still debatable whether urinary flow rates are increased or not. The aim of this study was to evaluate the acute effects of sildenafil, a PDE5 inhibitor, on uroflowmetry parameters. A total of 110 men who had applied to our outpatient clinics and who had had no history of alpha blocker and PDE5 inhibitor use were included in our study. Two uroflowmetries were performed within 24–72 hours without any treatment. Participants received 50 mg of sildenafil at their third visit, and uroflowmetry was repeated after 2 hours. A total of 102 men were included in the analysis, and baseline uroflowmetry values were compared with values obtained after sildenafil use. The mean age of the 102 participants who had attended all three visits (92.7%) was 52.1 ± 12.2 years. Mean of baseline maximal flow rate values were 17.1 ± 5.1 mL/s, mean of baseline maximal flow rate after sildenafil was 18.2 ± 5.1 mL/s; average flow rate values at the baseline and after sildenafil were 9.5 ± 3.5 and 9.9 ± 3.5 mL/s, respectively. Means of postvoid residual urine volume for baseline and after sildenafil were 31.2 ± 20.1 and 27.7 ± 18.4 mL, respectively. Statistically significant difference is determined between baseline and postsildenafil values in terms of average flow rates at baseline and postvoid residual urine values. Results of this study suggest that sildenafil has an effect on uroflowmetric parameters during an acute period.
Chronic Oral Administration of the Arginase Inhibitor 2(S)‐amino‐6‐boronohexanoic Acid (ABH) Improves Erectile Function in Aged Rats
Authors: Segal Robert , Hannan Johanna L. , Liu Xiaopu , Kutlu Omer , Burnett Arthur L. , Champion Hunter C. , Kim Jae Hyung , Steppan Jochen , Berkowitz Dan E. , Bivalacqua Trinity J.
Published: November 2012

Abstract: Arginase expression and activity have been noted to be heightened in conditions associated with erectile dysfunction, including aging. Previously, arginase inhibition by chronic administration of the arginase inhibitor 2‐(S)‐amino‐6‐boronohexanoic acid (ABH) has been shown to improve endothelial dysfunction in aged rats. The objective of this study was to assess whether chronic oral ABH administration affects cavernosal erectile function. Rats were divided into 4 groups: young control, young treated with arginase inhibitor, aged control, and aged treated with arginase inhibitor. Arginase activity was measured and presented as a proportion of young untreated rats. In vivo erectile responses to cavernous nerve stimulation were measured in all cohorts. The cavernous nerve was stimulated with a graded electrical stimulus, and the intracavernosal/mean arterial pressure ratios and total intracavernosal pressure were recorded. Arginase activity was elevated in the aged rats compared with young controls; however, arginase activity was significantly decreased in aged rats treated with ABH. With the addition of ABH, erectile responses improved in the aged rats (P < .05). Oral inhibition of arginase with ABH results in improved erectile function in aged rats, resulting in erectile hemodynamics similar to young rats. This represents the first documentation of systemic arginase inhibition positively affecting corporal cavernosal function.
A Simplified Approach to Assessing Penile Endothelial Function in Young Individuals at Risk of Erectile Dysfunction
Authors: Wu Hsien‐Tsai , Lee Chun‐Ho , Chen Chin‐Jung , Tsai I‐Ting , Sun Cheuk‐Kwan
Published: November 2012

Abstract: Erectile dysfunction (ED) reflects a risk for systemic cardiovascular diseases by virtue of a common etiology of vascular endothelial dysfunction, which is increasingly reported to affect young adults. On the basis of physiological phenomenon of reactive hyperemia (RH), systemic and penile endothelial functions in healthy young adults were compared with the use of digital data on arterial waveforms before and after RH induction. Between July 2009 and March 2011, 32 young adult volunteers with normal erectile functions were recruited. Questionnaires on medical histories and sexual functions and blood samples for testosterone and biochemical analyses were obtained. Dilatation index (DI) and penile arterial waveform amplitude (PAWA) ratios for assessing systemic and penile endothelial function were acquired with an air pressure sensing system on the arm and a penile arterial waveform analyzing system on the penis, respectively. A total cholesterol/high‐density lipoprotein (TC/HDL) ratio greater than 4.1 was used to define high risk for ED. Remarkable positive correlation was noted between DI and PAWA ratio (r / .640, P < .001). DI showed significant positive associations with serum testosterone (P = .012) and serum HDL level, whereas it showed negative correlations with total triglyceride and glycosylated hemoglobulin levels, body weight, waist circumference, body mass index, and diastolic blood pressure. Similarly, the PAWA ratio showed significant positive correlations with serum testosterone (P < .001) and HDL levels, but negative associations with body weight, waist circumference, and body mass index. Both DI and PAWA ratio successfully identified participants at high risk for ED (eg, TC/HDL ratio > 4.1; P < .05). Our results demonstrated that penile endothelial function can be assessed by evaluating systemic endothelial function in young healthy adults for early identification of risk for ED.
Seasonal Fluctuations in Testosterone‐Estrogen Ratio in Men From the Southwest United States
Authors: Moskovic Daniel J. , Eisenberg Michael L. , Lipshultz Larry I.
Published: November 2012

Abstract: Although controversial, seasonal variations in testosterone have been observed in several populations of men throughout the world. This finding might have an impact on screening and treatment of hypogonadism. We examined the circannual patterns of sex hormones in the Southwest United States. A prospectively assembled database of almost 11 000 patients in a men's health practice was used to collect data on testosterone, estradiol, sex hormone–binding globulin (SHBG), follicle‐stimulating hormone (FSH), luteinizing hormone (LH), and dehydroepiandrosterone‐sulfate (DHEA‐S). Patient age, address, and date of visit were recorded. Of note, testosterone‐estrogen ratio (T/E ratio) and free testosterone were calculated values. The data were grouped by month and by season (3‐month intervals beginning with June, July, and August as summer). Analysis of variance was used to compare hormone levels between seasonal and monthly data sets, with P < .05 regarded as statistical significance. Statistically significant differences in estradiol (P / .02), T/E ratio (P < .01), FSH (P = .02), and SHBG (P < .01) were observed between seasons. Peak‐to‐trough variations were as follows: 6% for estradiol, 16.5% for T/E ratio, 11.0% for FSH, and 11.6% for SHBG. The T/E ratio peaked in the spring and was at its nadir in the fall. No differences in testosterone (P = .21), LH (P = .25), free testosterone (P = .08), and DHEA‐S (P = .11) were observed. Statistically significant evidence of variation in estradiol and T/E ratio were identified in the men included in this study. Although this is consistent with seasonal body habitus changes, physical activity levels, and hypothesized hormonal patterns, the variability reported in the literature makes further trials covering a broader geographic region important to confirm the findings.
Circulating Endothelial Cells as Marker of Endothelial Damage in Male Hypogonadism
Authors: Milardi Domenico , Grande Giuseppe , Giampietro Antonella , Vendittelli Francesca , Palumbo Sara , Tartaglione Linda , Marana Riccardo , Pontecorvi Alfredo , de Marinis Laura , Zuppi Cecilia , Capoluongo Ettore
Published: November 2012

Abstract: Testosterone deficiency has become a frequently diagnosed condition in today's society affected by epidemic obesity, and is associated with cardiovascular risk. Recent studies have established the importance of altered vascular endothelium function in cardiovascular disease. The damage to the endothelium might also cause endothelial cell detachment, resulting in increased numbers of circulating endothelial cells (CEC) within the bloodstream. To evaluate whether hypogonadism could modify CEC count in peripheral bloodstream, we investigated peripheral blood CEC count using the CellSearch System, a semiautomatic method to accurately and reliably enumerate CECs, which are sorted based on a CD146+, CD105+, DAPI+, CD45‐ phenotype, in a population of 20 patients with hypogonadism. The control group comprised 10 age‐ and sex‐matched healthy participants. CEC count per milliliter was significantly increased in patients with hypogonadism vs the control group. In the group with hypogonadism, an inverse exponential correlation was present between testosterone levels and CEC count per milliliter. A direct linear correlation was present between waist circumference and CECs and between body mass index and CECs. The regression analysis showed that testosterone was the significant independent determinant of CECs. Our results underline that male hypogonadism is associated with endothelial dysfunction. The correlation between CEC and waist circumference underlines that visceral obesity may be synergically implicated in this regulation. Future studies are required to unveil the mechanisms involved in the pathogenesis of testosterone‐induced endothelial disfunction, which may provide novel therapeutic targets to be incorporated in the management of hypogonadism.
The Genetics of Male Fertility—From Basic Science to Clinical Evaluation
Authors: Pastuszak Alexander W. , Lamb Dolores J.
Published: November 2012

Abstract: Our understanding of male fertility has increased dramatically over the past several decades, in large part because of advances in technology and the ability to rapidly analyze large quantities of high‐resolution genetic data. These research efforts have led to an understanding of some of the genes involved in male fertility and have enabled us to test for defects in these genes that result in infertility in men. However, our understanding of male fertility remains far from comprehensive, and many genes involved in male fertility likely remain to be identified and their mechanisms of action elucidated. This can only be accomplished through continued, persistent investigations using cutting‐edge technologies. In this review, we discuss the history of genetic testing and how it applies to male fertility, from the identification of the sex chromosomes at the turn of the century to classification of single‐nucleotide polymorphisms that may result in infertility and are the crux of modern genetic analysis. We discuss the genetic testing methodologies traditionally used for genetic assessment of infertile males, including karyotype analysis, sperm fluorescence in situ hybridization, and polymerase chain reaction–based testing for Y chromosomal evaluation, as well as cutting‐edge genetic testing methodologies using microarrays and whole‐genome sequencing, permitting analysis at a nucleotide‐level resolution. Finally, we describe our vision of the future of genetic testing in the setting of male infertility, culminating in truly personalized medicine for each affected infertile male.