bluuebunny/crossref_metadata_2025 huggingface dataset:
Model Organic Surfaces to Probe Marine Bacterial Adhesion Kinetics by Surface Plasmon Resonance
Authors: Pranzetti Alice , Salaün Stéphanie , Mieszkin Sophie , Callow Maureen E. , Callow James A. , Preece Jon A. , Mendes Paula M.
Published: May 2012

Understanding how bacteria adhere to a surface is a critical step in the development of novel materials and coatings to prevent bacteria forming biofilms. Here, surface plasmon resonance (SPR) spectroscopy, in combination with self‐assembled monolayers (SAMs) that have different backbone structures and/or functional groups, is used for the first time to study the initial stages of bacterial adhesion to surfaces (i.e., initial interaction of cells with a surface, a process governed by van der Waals, electrostatic, and hydrophobic interactions). The work highlights SPR spectroscopy as a powerful and unique approach to probe bacterial adhesion in real time. SPR spectral data reveal different kinetics of adhesion for the interaction of two marine bacterial species (Marinobacter hydrocarbonoclasticus and Cobetia marina) to a range of organosulfur SAMs. Furthermore, the extent of adhesion is dependent on the backbone structures and functional groups of the SAMs. The role of extracellular polymeric substances (EPS) in bacterial adhesion is also investigated. Pre‐conditioning experiments with cell‐free culture supernatants, containing planktonic EPS, allow quantification of the amount adsorbed onto surfaces and directly account for the impact of EPS adsorption on bacterial adhesion in the assay. While the physicochemical characteristics of the surfaces play a significant role in determining bacterial cell adhesion for low levels of conditioning by planktonic EPS, greater levels of conditioning by EPS reduce the difference between surfaces.
Selective Functionalization of 3D Matrices Via Multiphoton Grafting and Subsequent Click Chemistry
Authors: Ovsianikov Aleksandr , Li Zhiquan , Torgersen Jan , Stampfl Jürgen , Liska Robert
Published: May 2012

Grafting is a popular approach for adjusting the properties and functionalization of various surfaces. Conventional photoinduced grafting has been utilized on flat surfaces, porous monoliths, and hydrogels. By masking or illuminating only a portion of the sample, a certain degree of spatial and temporal control is possible, but the ability to use grafting to pattern in 3D is limited. Here, the laser‐induced photolysis of an aromatic azide compound is employed for true 3D photografting within a poly(ethylene glycol) (PEG)‐based matrix. Since the multiphoton interaction occurs only in a confined area within the laser focal spot, the localized immobilization of a selected molecule with high spatial resolution in 3D is possible. In contrast to the widely utilized chain‐growth polymerization‐based grafting, the approach is characterized by a single‐molecule insertion mechanism. Successful binding of the fluorophore is confirmed by laser scanning microscopy. To test for the presence of latent azides and to determine the suitability for additional postmodification with arbitrary functional groups, the sample is further subjected to copper‐catalyzed alkyne click‐reaction conditions. The described 3D photografting method is simple, highly efficient, and universal. The presented results demonstrate the great potential of multiphoton‐induced grafting for 3D site‐specific functionalization.
Sodium‐Ion Batteries
Authors: Slater Michael D. , Kim Donghan , Lee Eungje , Johnson Christopher S.
Published: May 2012

The status of ambient temperature sodium ion batteries is reviewed in light of recent developments in anode, electrolyte and cathode materials. These devices, although early in their stage of development, are promising for large‐scale grid storage applications due to the abundance and very low cost of sodium‐containing precursors used to make the components. The engineering knowledge developed recently for highly successful Li ion batteries can be leveraged to ensure rapid progress in this area, although different electrode materials and electrolytes will be required for dual intercalation systems based on sodium. In particular, new anode materials need to be identified, since the graphite anode, commonly used in lithium systems, does not intercalate sodium to any appreciable extent. A wider array of choices is available for cathodes, including high performance layered transition metal oxides and polyanionic compounds. Recent developments in electrodes are encouraging, but a great deal of research is necessary, particularly in new electrolytes, and the understanding of the SEI films. The engineering modeling calculations of Na‐ion battery energy density indicate that 210 Wh kg−1 in gravimetric energy is possible for Na‐ion batteries compared to existing Li‐ion technology if a cathode capacity of 200 mAh g−1 and a 500 mAh g−1 anode can be discovered with an average cell potential of 3.3 V.
Hybrid Nanoparticles for Detection and Treatment of Cancer
Authors: Sailor Michael J. , Park Ji‐Ho
Published: May 2012

There is currently considerable effort to incorporate both diagnostic and therapeutic functions into a single nanoscale system for the more effective treatment of cancer. Nanoparticles have great potential to achieve such dual functions, particularly if more than one type of nanostructure can be incorporated in a nanoassembly, referred to in this review as a hybrid nanoparticle. Here we review recent developments in the synthesis and evaluation of such hybrid nanoparticles based on two design strategies (barge vs. tanker), in which liposomal, micellar, porous silica, polymeric, viral, noble metal, and nanotube systems are incorporated either within (barge) or at the surface of (tanker) a nanoparticle. We highlight the design factors that should be considered to obtain effective nanodevices for cancer detection and treatment.
Influence of Phonon Scattering on Exciton and Charge Diffusion in Polymer‐Fullerene Solar Cells
Authors: Presselt Martin , Herrmann Felix , Hoppe Harald , Shokhovets Sviatoslav , Runge Erich , Gobsch Gerhard
Published: May 2012

Thermally activated transport and phonon scattering in P3HT:PCBM (poly(3‐hexylthiophene‐2,5‐diyl):[6,6]‐phenylC61‐butyric acid methyl ester) bulk heterojunction (BHJ) organic solar cells is studied via temperature‐dependent external‐quantum‐efficiency (EQE) spectroscopy. The hopping barriers for combined exciton and charge transport are balanced for the individual blended materials in a sample, which possesses a blending ratio and a morphology that give rise to a maximal power‐conversion efficiency. Increasing the PCBM weight fraction leads to a reduction of exciton hopping barriers in PCBM, while for P3HT exciton hopping barriers remain constant. This reduction of PCBM exciton hopping barriers is attributed to a higher PCBM crystallinity in the PCBM‐rich solar cell as compared to the BHJ with the optimized blending ratio. The morphology‐dependent difference in exciton hopping activation energies between P3HT and PCBM is attributed to a higher impact of phonon scattering in P3HT than in PCBM, as concluded from the much stronger decrease of P3HT‐related temperature‐dependent external quantum efficiencies above room temperature in the PCBM‐rich BHJ solar cell. All EQE data of P3HT:PCBM‐based BHJ solar cells is modeled consistently over a broad temperature range by a simple analytical expression involving temperature activation and phonon scattering, without the need to distinguish two separate hopping regimes.
Ionomigration of Neutral Phases in Ionic Conductors
Authors: Chen I.‐Wei , Kim Seung‐Wan , Li Ju , Kang Suk‐Joong L. , Huang Fuqiang
Published: May 2012

Without sensing any physical force, a neutral object in an ion conducting solid can move in a uniform electrochemical field by coupling a global ion wind with localized counterion diffusion at the interface. This happens to pores and gas bubbles at 840 °C in a fast O2− conductor, yttria‐stabilized zirconia (YSZ), despite having cations that are essentially frozen with lattice diffusivities 1012 times slower than the O2− diffusivity. Through‐thickness migration and massive electro‐sintering in thin YSZ ceramics are observed at voltages similar to those in YSZ fuel cells and electrolysis cells. This effect should apply to any electrochemically‐loaded multiphase ionic conducting solid, with or without an electric field, and can lead to electrolyte sintering, phase accumulation and electrode debonding, resulting in unexpected benefit or damage in electrochemical devices. As the velocity obeys a pseudo Stokes‐Einstein equation, inversely proportional to the object size, an especially enhanced size effect is expected in nanocomposites.
Thermodynamic Efficiency Limit of Molecular Donor‐Acceptor Solar Cells and its Application to Diindenoperylene/C60‐Based Planar Heterojunction Devices
Authors: Gruber Mark , Wagner Julia , Klein Konrad , Hörmann Ulrich , Opitz Andreas , Stutzmann Martin , Brütting Wolfgang
Published: May 2012

In organic photovoltaic (PV) cells, the well‐established donor‐acceptor (D/A) concept enabling photo‐induced charge transfer between two partners with suitable energy level alignment has proven extremely successful. Nevertheless, the introduction of such a heterojunction is accompanied with additional energy losses as compared to an inorganic homojunction cell, owing to the presence of a charge‐transfer (CT) state at the D/A interface. Based on the principle of detailed balance, a modified Shockley‐Queisser theory is developed including the essential effects of interfacial CT states, that allows for a quantitative assessment of the thermodynamic efficiency limits of molecular D/A solar cells. Key parameters, apart from the optical gap of the absorber material, entering the model are the energy (ECT) and relative absorption strength (αCT) of the CT state. It is demonstrated how the open‐circuit voltage (VOC) and thus the power conversion efficiency are affected by different parameter values. Furthermore, it is shown that temperature dependent device characteristics can serve to determine the CT energy, and thus the upper limit of VOC for a given D/A combination, as well as to quantify non‐radiative recombination losses. The model is applied to diindenoperylene (DIP)‐based photovoltaic devices, with open‐circuit voltages between 0.9 and 1.4 V, depending on the partner, that have recently been reported.
Chronic myelomonocytic leukemia: 2012 update on diagnosis, risk stratification, and management
Authors: Parikh Sameer A. , Tefferi* Ayalew
Published: May 2012

Disease Overview: Chronic myelomonocytic leukemia (CMML) is a clonal hematopoietic stem cell disorder that is classified as a myelodysplastic/myeloproliferative neoplasm by the 2008 World Health Organization classification of hematopoietic tumors. It is characterized by absolute monocytosis (>1 × 109 L−1) in the peripheral blood that persists for at least 3 months. Patients may present with symptoms related to cytopenias and/or an underlying hypercatabolic state with drenching night sweats, splenomegaly, and weight loss.

Diagnosis: The diagnosis of CMML rests on a combination of morphologic, histopathologic, and chromosomal abnormalities in the bone marrow, after careful exclusion of other conditions (both malignant and nonmalignant) that can cause monocytosis. Numerous molecular abnormalities have been recently recognized in patients with CMML—unfortunately, no single pathognomonic finding specific to CMML has been identified thus far.

Risk stratification: The International Prognostic Scoring System for myelodysplastic syndrome (MDS) cannot be used to risk stratify patients with CMML because this model excluded patients with a leukocyte count >12 × 109 L−1. Other risk stratification models such as the MD Anderson prognostic score and Dusseldorf score have been published. In the only model that took karyotype into account, bone marrow blasts ≥ 10%, leukocyte count ≥ 13 × 109 L−1, hemoglobin < 10 g/dL, platelet count < 100 × 109 L−1, and presence of trisomy 8, abnormalities of chromosome 7, or complex karyotype were found to be independent predictors of adverse survival.

Risk‐adapted therapy: The Food and Drug Administration has approved azacitidine and decitabine for the treatment of patients with CMML based on two pivotal trials in MDS. Novel classes of agents including immunomodulatory drugs, nucleoside analogs, and small‐molecule tyrosine kinase inhibitors are being investigated in the treatment of CMML. With the advent of reduced intensity conditioning, an allogeneic stem cell transplant has also become a viable option for a subset of patients. Am. J. Hematol. 87:610–619, 2012. © 2012 Wiley Periodicals, Inc.
Beckwith–Wiedemann syndrome in sibs discordant for IC2 methylation
Authors: Niederhoffer Karen Y. , Peñaherrera Maria , Pugash Denise , Rupps Rosemarie , Arbour Laura , Tessier Francine , Choufani Sanaa , Zhao Chunhua , Manokhina Irina , Shuman Cheryl , Robinson Wendy P. , Weksberg Rosanna , Boerkoel Cornelius F.
Published: May 2012

Genetically heterogeneous imprinting disorders include Beckwith–Wiedemann syndrome (BWS) and multiple maternal hypomethylation syndrome (MMHS). Using DNA sequencing, quantitative PCR, SNuPE, pyrosequencing, and hybridization to the Illumina GoldenGate Methylation Cancer Panel 1 array, we characterized the genomic DNA of two brothers with BWS who were discordant for loss of methylation at several differentially methylated regions (DMR), including imprinting center 2 (IC2) on chromosome band 11p15.5, which is often hypomethylated in BWS. In keeping with MMHS, the elder child had hypomethylation of SGCE and PLAGL1 as well as of IC2, whereas the younger brother demonstrated no loss of methylation at these DMRs. Although this discordance is consistent with the observation that 15–20% of individuals with BWS do not have detectable genetic or epigenetic alterations of 11p15.5, this is the first report of familial recurrence of BWS with discordance for chromosomal 11p15.5 alterations. We hypothesize that this apparent discordance arises either from mosaicism precluding identification of IC2 hypomethylation in blood or buccal mucosa DNA of the younger child, or from hypomethylation at a site not interrogated by our molecular studies. © 2012 Wiley Periodicals, Inc.
Interpreting food processing through dietary mechanical properties: A Lemur catta case study
Authors: Yamashita Nayuta , Cuozzo Frank P. , Sauther Michelle L.
Published: May 2012

Knowledge of dietary mechanical properties can be informative about physical consequences to consumers during ingestion and mastication. In this article, we examine how Tamarindus indica fruits can affect dental morphology in a population of ring‐tailed lemurs (Lemur catta) at Beza Mahafaly special reserve in southwestern Madagascar. Ring‐tailed lemurs in tamarind dominated gallery forests exhibit extreme wear and tooth loss on their postcanine dentition that has been related to processing T. indica fruits. We measured and compared mechanical properties of individual food parts in the diet of ring‐tailed lemurs in different seasons in 1999–2000, 2008, and 2010. Fracture toughness, hardness, and modulus of foods were measured with a portable mechanical tester. The ripe fruits of T. indica are indeed the toughest and hardest foods ingested by the lemurs. In addition, they are among the largest foods consumed, require high numbers of ingestive bites to process, and are the most frequently eaten by volume. During controlled cutting tests of the ripe fruit shell, multiple runaway side cracks form alongside the cut. Similarly, the lemurs repeatedly bite the ripe shell during feeding and thereby introduce multiple cracks that eventually fragment the shell. Studies of enamel microstructure (e.g., Lucas et al.: BioEssays 30 (2008) 374–385; Campbell et al., 2011) advance the idea that the thin enamel of ring‐tailed lemur teeth is susceptible to substantial micro‐cracking that rapidly erodes the teeth. We conclude that micro‐cracking from repeated loads, in combination with the mechanical and physical properties of the fruit, is primarily responsible for the observed dental damage. Am J Phys Anthropol 148:205–214, 2012. © 2012 Wiley Periodicals, Inc.
The impact of dental impairment on ring‐tailed lemur food processing performance
Authors: Millette James B. , Sauther Michelle L. , Cuozzo Frank P. , Ness Jenifer L.
Published: May 2012

During mastication, foods are reduced into particles suitable for swallowing and digestion. Smaller particles possess a greater surface area per unit of volume on which digestive enzymes and bacteria may work than relatively larger particles, and are thus more readily digested. As dental morphology facilitates the breakdown of diets with specific mechanical properties, extensive dental wear and/or tooth loss may impede an individual's ability to break down and exploit foods. We present data demonstrating a relationship between dental impairment and particle size in 43 fecal samples from 33 ring‐tailed lemurs at the Beza Mahafaly Special Reserve (BMSR), Madagascar. All fecal samples were sifted through three sieves of decreasing size (11.2 mm, 4.75 mm, and 1.0 mm). The resulting fraction in each sieve was then weighed and assessed in relation to individual dental impairment status. With increasing wear, the percentage of each sample within the 1.0 mm sieve decreases, whereas that in the 11.2 mm sieve increases with increasing postcanine wear, although these effects are not present when limited to individuals without tooth loss. Individuals with tooth loss also demonstrate larger proportions of fecal material 1.0–4.75 mm in size. Dental impairment results in larger food particles and potentially less efficient utilization of foods. When fecal material was examined by leaf vs. fruit content, individuals with tooth loss demonstrated reduced proportions of fruit in the 1.0 mm and 11.2 mm sieves. These data suggest individuals with tooth loss consume less fruit than those without loss, potentially reflecting a reduced ability to process tamarind fruit, a key fallback resource at BMSR. Am J Phys Anthropol 148:238–248, 2012. © 2012 Wiley Periodicals, Inc.
Dental topography indicates ecological contraction of lemur communities
Authors: Godfrey Laurie R. , Winchester Julia M. , King Stephen J. , Boyer Doug M. , Jernvall Jukka
Published: May 2012

Understanding the paleoecology of extinct subfossil lemurs requires reconstruction of dietary preferences. Tooth morphology is strongly correlated with diet in living primates and is appropriate for inferring dietary ecology. Recently, dental topographic analysis has shown great promise in reconstructing diet from molar tooth form. Compared with traditionally used shearing metrics, dental topography is better suited for the extraordinary diversity of tooth form among subfossil lemurs and has been shown to be less sensitive to phylogenetic sources of shape variation. Specifically, we computed orientation patch counts rotated (OPCR) and Dirichlet normal energy (DNE) of molar teeth belonging to 14 species of subfossil lemurs and compared these values to those of an extant lemur sample. The two metrics succeeded in separating species in a manner that provides insights into both food processing and diet. We used them to examine the changes in lemur community ecology in Southern and Southwestern Madagascar that accompanied the extinction of giant lemurs. We show that the poverty of Madagascar's frugivore community is a long‐standing phenomenon and that extinction of large‐bodied lemurs in the South and Southwest resulted not merely in a loss of guild elements but also, most likely, in changes in the ecology of extant lemurs. Am J Phys Anthropol 148:215–227, 2012. © 2012 Wiley Periodicals, Inc.
Linear enamel hypoplasia as an indicator of physiological stress in great apes: Reviewing the evidence in light of enamel growth variation
Authors: Guatelli‐Steinberg Debbie , Ferrell Rebecca J. , Spence Jennifer
Published: May 2012

Physiological stress, such as malnutrition or illness, can disrupt normal enamel growth, resulting in linear enamel hypoplasias (LEHs). Although ecological factors may contribute to LEH expression, other factors, such as surface abrasion and enamel growth variables, are also likely to be involved. Attention to these other factors is necessary before we can begin to understand what LEH might signify in terms of ecological sources of physiological stress in non‐human primates. This study focuses on assessing the contribution of these other factors to variation in LEH expression within and across great ape taxa. Here, we present LEH data from unabraded crown regions in samples of seven great ape species. We analyze these data with respect to lateral enamel formation time and the angles that striae of Retzius make with the enamel surface, as these variables are expected to affect variation in LEH expression. We find that although the duration of enamel formation is associated with sex differences in LEH expression, it is not clearly related to taxonomic variation in LEH expression, and does not explain the low frequency of LEH in mountain gorillas found in this and a previous study. Our data on striae of Retzius angles suggest that these influence LEH expression along the tooth crown and may contribute to the consistently high frequencies of LEH seen in Pongo in this and previous studies. We suggest that future work aimed at understanding species variation in these angles is crucial to evaluating taxonomic patterns of LEH expression in great apes. Am J Phys Anthropol 148:191–204, 2012. © 2012 Wiley Periodicals, Inc.
Variation of bone collagen amino acid δ13c values in archaeological humans and fauna with different dietary regimes: Developing frameworks of dietary discrimination
Authors: Honch Noah V. , McCullagh James S.O. , Hedges Robert E.M.
Published: May 2012

We present bone collagen amino acid (AA) δ13C values for a range of archaeological samples representing four “benchmark” human diet groups (high marine protein consumers, high freshwater protein consumers, terrestrial C3 consumers, and terrestrial C4 consumers), a human population with an “unknown” diet, and ruminants. The aim is to establish an interpretive palaeodietary framework for bone collagen AA δ13C values, and to assess the extent to which AA δ13C values can provide additional dietary information to bulk collagen stable isotope analysis. Results are analyzed to determine the ability of those AAs for which we have a complete set, to discriminate between the diet groups. We show that very strong statistical discrimination is obtained for all interdiet group comparisons. This is often obvious from suitably chosen bivariate plots using δ113C values that have been normalized to compensate for interdiet group differences in bulk δ13C values. Bi‐plots of non‐normalized phenylalanine and valine δ13C values are useful for distinguishing aquatic diets (marine and freshwater) from terrestrial diets. Our interpretive framework uses multivariate statistics (e.g., discriminant analysis) to optimize the separation of the AA δ13C values of the “benchmark”’ diet groups, and is capable of accurately assigning external samples to their expected diet groups. With a growing body of AA δ13C values, this method is likely to enhance palaeodietary research by allowing the “unknown” diets of populations under investigation to be statistically defined relative to the well‐characterized or “known” diets of previously investigated populations. Am J Phys Anthropol 2012. © 2012 Wiley Periodicals, Inc.
Primate dental ecology: How teeth respond to the environment
Authors: Cuozzo Frank P. , Ungar Peter S. , Sauther Michelle L.
Published: May 2012

Teeth are central for the study of ecology, as teeth are at the direct interface between an organism and its environment. Recent years have witnessed a rapid growth in the use of teeth to understand a broad range of topics in living and fossil primate biology. This in part reflects new techniques for assessing ways in which teeth respond to, and interact with, an organism's environment. Long‐term studies of wild primate populations that integrate dental analyses have also provided a new context for understanding primate interactions with their environments. These new techniques and long‐term field studies have allowed the development of a new perspective—dental ecology. We define dental ecology as the broad study of how teeth respond to, or interact with, the environment. This includes identifying patterns of dental pathology and tooth use–wear, as they reflect feeding ecology, behavior, and habitat variation, including areas impacted by anthropogenic disturbance, and how dental development can reflect environmental change and/or stress. The dental ecology approach, built on collaboration between dental experts and ecologists, holds the potential to provide an important theoretical and practical framework for inferring ecology and behavior of fossil forms, for assessing environmental change in living populations, and for understanding ways in which habitat impacts primate growth and development. This symposium issue brings together experts on dental morphology, growth and development, tooth wear and health, primate ecology, and paleontology, to explore the broad application of dental ecology to questions of how living and fossil primates interact with their environments. Am J Phys Anthropol 148:159–162, 2012. © 2012 Wiley Periodicals, Inc.
Middle Paleolithic human remains from the Gruta Da Oliveira (Torres Novas), Portugal
Authors: Willman John C. , Maki Julia , Bayle Priscilla , Trinkaus Erik , Zilhão João
Published: May 2012

Additional Middle Paleolithic human remains from layers 17, 18, and 22 of the Gruta da Oliveira, Portugal consist of a proximal manual phalanx 2 (Oliveira 5), a partial postcanine tooth (Oliveira 6), a humeral diaphysis (Oliveira 7), a distal mandibular molar (Oliveira 8), and a mandibular premolar (P3) (Oliveira 9). Oliveira 5, 6, and 8 are unremarkable for Late Pleistocene humans. The Oliveira 7 right humerus is moderately robust or the individual had the stocky body proportions of other European (including Iberian) Neandertals. The Oliveira 9 P3 has a large and symmetrical crown and lacks a distal accessory ridge and accessory lingual cusps, overlapping both Neandertal and recent human ranges of variation. It contrasts with at least recent human P3s in having relatively thin enamel. These join the Oliveira 1 to 4 remains in further documenting early MIS 3 Neandertal morphology in western Iberia. Am J Phys Anthropol 2012. © 2012 Wiley Periodicals, Inc.
Application of microwave‐assisted click chemistry in the preparation of functionalized copolymers for drug conjugation
Authors: Hu Xiuli , Yan Lesan , Xiao Haihua , Li Xiaoyuan , Jing Xiabin
Published: May 2012

The aim of this study is to develop azido‐carrying biodegradable polymers and their postfunctionalization with alkynyl compounds via click chemistry and to investigate their potential use in drug delivery. Azido polymers were prepared by ring‐opening polymerization of cyclic carbonate monomer, 2,2‐bis(azidomethyl)trimethylene carbonate (ATC) with lactide using stannous octoate as catalyst. Several alkynyl compounds were selected to investigate the feasibility and reaction condition of click chemistry. With microwave‐assisting, the reaction time of click chemistry was shortened to 5 min. By using poly(ethylene glycol) (PEG) as macroinitiator, amphiphilic block copolymer mPEG‐b‐P(LA‐co‐ATC) was obtained and it could self‐assemble into micelles by solvent replacement method. The pendant groups were used for conjugating anticancer drugs gemcitabine and paclitaxel and fluorescent dye Rhodamine B. 3‐(4,5‐Dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide was used to assay the cytotoxicity of the conjugate micelles against SKOV‐3 and HeLa cell lines. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
The interferon signature and STAT1 expression in rheumatoid arthritis synovial fluid macrophages are induced by tumor necrosis factor α and counter‐regulated by the synovial fluid microenvironment
Authors: Gordon Rachael A. , Grigoriev Galina , Lee Angela , Kalliolias George D. , Ivashkiv Lionel B.
Published: May 2012

Objective

Type I interferons (IFNs) have emerged as potential activators of the IFN signature and elevated STAT‐1 expression in rheumatoid arthritis (RA) synovium, but mechanisms that induce synovial IFN expression are unknown. Recently, tumor necrosis factor α (TNFα) was shown to induce a delayed IFN response in macrophages. We undertook this study to test whether TNFα, classically thought to activate inflammatory NF‐κB target genes in RA, also contributes to the “IFN signature” in RA synovial macrophages.

Methods

Synovial fluid (SF) macrophages purified from 24 patients with RA and 18 patients with spondylarthritides (SpA) were lysed immediately after isolation or were cultured ex vivo in the absence or presence of blockade of endogenous type I IFN or TNFα. Expression of IFN‐inducible target genes was measured by quantitative reverse transcription–polymerase chain reaction, and expression of their corresponding proteins was measured by enzyme‐linked immunosorbent assay.

Results

Expression of an IFN signature and STAT1 in RA synovial macrophages was suppressed when type I IFNs or TNFα were blocked, whereas TNFα blockade did not affect expression of IFN response genes or STAT1 in SpA synovial macrophages. RA SF suppressed the IFN signature in RA synovial macrophages and in TNFα‐, IFNα‐, and IFNβ‐stimulated control macrophages. Type I IFNs suppressed expression of IL8 and MMP9 in RA synovial macrophages and in TNFα‐stimulated control macrophages.

Conclusion

Our findings identify a new function of TNFα in RA synovitis by implicating TNFα as a major inducer of the RA synovial IFN response. The results suggest that the expression of IFN response genes in RA synovium is regulated by interplay between TNFα and opposing homeostatic factors expressed in the synovial microenvironment.
Organic–Inorganic Hybrids Based on Ultrathin Oxide Layers: Designed Nanostructures for Molecular Recognition
Authors: Okada Tomohiko , Ide Yusuke , Ogawa Makoto
Published: May 2012

The application of layered solids for molecular recognition is summarized. By using layered solids (silicates, aluminosilicates, titanates, hydroxides, and so on), ions and molecules can be concentrated from aqueous and vapor phases. The large surface area and tunable surface properties derived from the layered structures contribute to molecular recognition. The choice of materials and modification of the nanostructure were carefully investigated to optimize the performance based on molecular recognition (selective adsorption, substrate selective reaction, detection, etc.). The progress made in materials syntheses (variation of layered materials, sophisticated modification, controlled morphology, and processing) has made the design of materials more attractive and realistic.
Integrated biogas upgrading and hydrogen utilization in an anaerobic reactor containing enriched hydrogenotrophic methanogenic culture
Authors: Luo Gang , Angelidaki Irini
Published: May 2012

Biogas produced by anaerobic digestion, is mainly used in a gas motor for heat and electricity production. However, after removal of CO2, biogas can be upgraded to natural gas quality, giving more utilization possibilities, such as utilization as autogas, or distant utilization by using the existing natural gas grid. The current study presents a new biological method for biogas upgrading in a separate biogas reactor, containing enriched hydrogenotrophic methanogens and fed with biogas and hydrogen. Both mesophilic‐ and thermophilic anaerobic cultures were enriched to convert CO2 to CH4 by addition of H2. Enrichment at thermophilic temperature (55°C) resulted in CO2 and H2 bioconversion rate of 320 mL CH4/(gVSS h), which was more than 60% higher than that under mesophilic temperature (37°C). Different dominant species were found at mesophilic‐ and thermophilic‐enriched cultures, as revealed by PCR–DGGE. Nonetheless, they all belonged to the order Methanobacteriales, which can mediate hydrogenotrophic methanogenesis. Biogas upgrading was then tested in a thermophilic anaerobic reactor under various operation conditions. By continuous addition of hydrogen in the biogas reactor, high degree of biogas upgrading was achieved. The produced biogas had a CH4 content, around 95% at steady‐state, at gas (mixture of biogas and hydrogen) injection rate of 6 L/(L day). The increase of gas injection rate to 12 L/(L day) resulted in the decrease of CH4 content to around 90%. Further study showed that by decreasing the gas–liquid mass transfer by increasing the stirring speed of the mixture the CH4 content was increased to around 95%. Finally, the CH4 content around 90% was achieved in this study with the gas injection rate as high as 24 L/(L day). Biotechnol. Bioeng. 2012; 109: 2729–2736. © 2012 Wiley Periodicals, Inc.
AS1411 aptamer tagged PLGA‐lecithin‐PEG nanoparticles for tumor cell targeting and drug delivery
Authors: Aravind Athulya , Jeyamohan Prashanti , Nair Remya , Veeranarayanan Srivani , Nagaoka Yutaka , Yoshida Yasuhiko , Maekawa Toru , Kumar D. Sakthi
Published: May 2012

Liposomes and polymers are widely used drug carriers for controlled release since they offer many advantages like increased treatment effectiveness, reduced toxicity and are of biodegradable nature. In this work, anticancer drug‐loaded PLGA‐lecithin‐PEG nanoparticles (NPs) were synthesized and were functionalized with AS1411 anti‐nucleolin aptamers for site‐specific targeting against tumor cells which over expresses nucleolin receptors. The particles were characterized by transmission electron microscope (TEM) and X‐ray photoelectron spectroscopy (XPS). The drug‐loading efficiency, encapsulation efficiency and in vitro drug release studies were conducted using UV spectroscopy. Cytotoxicity studies were carried out in two different cancer cell lines, MCF‐7 and GI‐1 cells and two different normal cells, L929 cells and HMEC cells. Confocal microscopy and flowcytometry confirmed the cellular uptake of particles and targeted drug delivery. The morphology analysis of the NPs proved that the particles were smooth and spherical in shape with a size ranging from 60 to 110 nm. Drug‐loading studies indicated that under the same drug loading, the aptamer‐targeted NPs show enhanced cancer killing effect compared to the corresponding non‐targeted NPs. In addition, the PLGA‐lecithin‐PEG NPs exhibited high encapsulation efficiency and superior sustained drug release than the drug loaded in plain PLGA NPs. The results confirmed that AS1411 aptamer‐PLGA‐lecithin‐PEG NPs are potential carrier candidates for differential targeted drug delivery. Biotechnol. Bioeng. 2012; 109: 2920–2931. © 2012 Wiley Periodicals, Inc.
Enhancement of neutral lipid productivity in the microalga Isochrysis affinis Galbana (T‐Iso) by a mutation‐selection procedure
Authors: Bougaran Gaël , Rouxel Catherine , Dubois Nolwenn , Kaas Raymond , Grouas Sophie , Lukomska Ewa , Le Coz Jean‐René , Cadoret Jean‐Paul
Published: May 2012

Microalgae offer a high potential for energetic lipid storage as well as high growth rates. They are therefore considered promising candidates for biofuel production, with the selection of high lipid‐producing strains a major objective in projects on the development of this technology. We developed a mutation‐selection method aimed at increasing microalgae neutral lipid productivity. A two step method, based on UVc irradiation followed by flow cytometry selection, was applied to a set of strains that had an initial high lipid content and improvement was assessed by means of Nile‐red fluorescence measurements. The method was first tested on Isochrysis affinis galbana (T‐Iso). Following a first round of mutation‐selection, the total fatty acid content had not increased significantly, being $262\pm 21\,{\rm mgTFA}\,{\rm (gC)}^{- {\rm 1}} $ for the wild type (WT) and $269\pm 49\,{\rm mgTFA}\,{\rm (gC)}^{- {\rm 1}} $ for the selected population (S1M1). Conversely, fatty acid distribution among the lipid classes was affected by the process, resulting in a 20% increase for the fatty acids in the neutral lipids and a 40% decrease in the phospholipids. After a second mutation‐selection step (S2M2), the total fatty acid content reached $409\pm 64\,{\rm mgTFA}\,{\rm (gC)}^{- {\rm 1}} $ with a fatty acid distribution similar to the S1M1 population. Growth rate remained unaffected by the process, resulting in a 80% increase for neutral lipid productivity. Biotechnol. Bioeng. 2012; 109: 2737–2745. © 2012 Wiley Periodicals, Inc.
Biodefluorination and biotransformation of fluorotelomer alcohols by two alkane‐degrading Pseudomonas strains
Authors: Kim Myung Hee , Wang Ning , McDonald Thomas , Chu Kung‐Hui
Published: May 2012

Fluorotelomer alcohols [FTOHs, F(CF2)nCH2CH2OH, n = 4, 6, and 8] are emerging environmental contaminants. Biotransformation of FTOHs by mixed bacterial cultures has been reported; however, little is known about the microorganisms responsible for the biotransformation. Here we reported biotransformation of FTOHs by two well‐studied Pseudomonas strains: Pseudomonas butanovora (butane oxidizer) and Pseudomonas oleovorans (octane oxidizer). Both strains could defluorinate 4:2, 6:2, and 8:2 FTOHs, with a higher degree of defluorination for 4:2 FTOH. According to the identified metabolites, P. oleovorans transformed FTOHs via two pathways I and II. The pathway I led to the production of x:2 ketone [dominant metabolite, F(CF2)xC(O)CH3; x = n − 1, n = 6 or 8], x:2 sFTOH [F(CF2)xCH(OH)CH3], and perfluorinated carboxylic acids (PFCAs, perfluorohexanoic, or perfluorooctanoic acid). The pathway II resulted in the formation of x:3 polyfluorinated acid [F(CF2)xCH2CH2COOH] and relatively minor shorter‐chain PFCAs (perfluorobutyric or perfluorohexanoic acid). Conversely, P. butanovora transformed FTOHs by using the pathway I, leading to the production of x:2 ketone, x:2 sFTOH, and PFCAs. This is the first study to show that individual bacterium can bio‐transform FTOHs via different or preferred transformation pathways to remove multiple CF2 groups from FTOHs to form shorter‐chain PFCAs. Biotechnol. Bioeng. 2012; 109: 3041–3048. © 2012 Wiley Periodicals, Inc.
Neutrophil dysfunction induced by hyperglycemia: modulation of myeloperoxidase activity
Authors: de Souza Ferreira Cláudia , Araújo Tomaz Henrique , Ângelo Marilene Lopes , Pennacchi Paula Commune , Okada Sabrina Sayori , de Araújo Paula Fernanda Borges , Migliorini Silene , Rodrigues Maria Rita
Published: May 2012

Our data suggest that impaired activity of myeloperoxidase (MPO) may play an important role in the dysfunction of neutrophils from hyperglycemic rats. Neutrophil biochemical pathways include the NADPH oxidase system and the MPO enzyme. They both play important role in the killing function of neutrophils. The effect of hyperglycemia on the activity of these enzymes and the consequences with regard to Candida albicans phagocytosis and the microbicidal property of rat peritoneal neutrophils is evaluated here. The NADPH oxidase system activity was measured using chemiluminescence and cytochrome C reduction assays. MPO activity was measured by monitoring HOCl production, and MPO protein expression was analysed using Western blot and immunofluorescence. C. albicans phagocytosis and death were evaluated by optical microscopy using the May–Grunwald–Giemsa staining method. ROS generation kinetic was slightly delayed in the diabetic group. MPO expression levels were higher in diabetic neutrophils; however, MPO activity was decreased in these same neutrophils compared with the controls. C. albicans phagocytosis and killing were lower in the diabetic neutrophils. Based on our experimental model, the phagocytic and killing functions of neutrophil phagocytosis are impaired in diabetic rats because of the decreased production of HOCl, highlighting the importance of MPO in the microbicidal function of neutrophils. Copyright © 2012 John Wiley & Sons, Ltd.
Papain‐Specific Activating Esters in Aqueous Dipeptide Synthesis
Authors: de Beer Roseri J. A. C. , Zarzycka Barbara , Mariman Michiel , Amatdjais‐Groenen Helene I. V. , Mulders Marc J. , Quaedflieg Peter J. L. M. , van Delft Floris L. , Nabuurs Sander B. , Rutjes Floris P. J. T.
Published: May 2012

Enzymatic peptide synthesis has the potential to be a viable alternative for chemical peptide synthesis. Because of the increasing commercial interest in peptides, new and improved enzymatic synthesis methods are desirable. In recently developed enzymatic strategies such as substrate mimetic approaches and enzyme‐specific activation, use of the guanidinophenyl ester (OGp) group has been shown to suffer from some drawbacks. OGp esters are sensitive to spontaneous chemical hydrolysis and the group is expensive to synthesize and therefore not suitable for large‐scale applications. On the basis of earlier computational studies, we hypothesized that OGp might be replaceable by simpler ester groups to make the enzyme‐specific activation approach to peptide bond formation more accessible. To this end, a set of potential activating esters (Z‐Gly‐Act) was designed, synthesized, and evaluated. Both the benzyl (OBn) and the dimethylaminophenyl (ODmap) esters gave promising results. For these esters, the scope of a model dipeptide synthesis reaction under aqueous conditions was investigated by varying the amino acid donor. The results were compared with those obtained from a previous study of Z‐XAA‐OGp esters. Computational docking analysis of the set of esters was performed in order to provide insight into the differences in the reactivities of all the potential activating esters. Finally, selected ODmap‐ and OBn‐activated amino acids were applied in the synthesis of two biologically active dipeptides on preparative scales.
Recognition by Nonaromatic and Stereochemical Subunit‐Containing Polyamides of the Four Watson–Crick Base Pairs in the DNA Minor Groove
Authors: Zhang Hong‐Fei , Wu Yan‐Ling , Jiang Shi‐Kun , Wang Pu , Sugiyama Hiroshi , Chen Xing‐Lai , Zhang Wen , Ji Yan‐Juan , Guo Chuan‐Xin
Published: May 2012

In order to develop an optimal subunit as a T‐recognition element in hairpin polyamides, 15 novel chirality‐modified polyamides containing (R)‐α,β‐diaminopropionic acid (Rβ), (S)‐α,β‐diaminopropionic acid (Sβ), (1R,3S)‐3‐aminocyclopentanecarboxylic acid (RSCp), (1S,3R)‐3‐amino‐cyclopentanecarboxylic acid (RSCp), (1R,3R)‐3‐aminocyclopentanecarboxylic acid (RRCp) and (1S,3S)‐3‐amino‐cyclopentanecarboxylic acid (SSCp) residues were synthesized. Their binding characteristics to DNA sequences 5′‐TGCNCAT‐3′/3′‐ACGN′GTA‐5′ (N⋅N′=A⋅T, T⋅A, G⋅C and C⋅G) were systemically studied by surface plasmon resonance (SPR) and molecular simulation (MSim) techniques. SPR showed that polyamide 4, AcIm‐Sβ‐ImPy‐γ‐ImPy‐β‐Py‐βDp (β/Sβ pair), bound to a DNA sequence containing a core binding site of 5′‐TGCACAT‐3′ with a dissociation equilibrium constant (KD) of 4.5×10−8 m. This was a tenfold improvement in specificity over 5′‐TGCTCAT‐3′ (KD=4.5×10−7 M). MSim studies supported the SPR results. More importantly, for the first time, we found that chiral 3‐aminocyclopentanecarboxylic acids in polyamides can be employed as base readers with only a small decrease in binding affinity to DNA. In particular, SPR showed that polyamide 9 (RRCp/β pair) had a 15‐fold binding preference for 5′‐TGCTCAT‐3′ over 5′‐TGCACAT‐3′. A large difference in standard free energy change for A⋅T over T⋅A was determined (ΔΔGo=5.9 kJ mol−1), as was a twofold decrease in interaction energy by MSim. Moreover, a 1:1 stoichiometry (9 to 5′‐TGCTCAT‐3′/3′‐ACGAGTA‐5′) was shown by MSim to be optimal for the chiral five‐membered cycle to fit the minor groove. Collectively, the study suggests that the (S)‐α‐amino‐β‐aminopropionic acid and (1R,3R)‐3‐aminocyclopentanecarboxylic acid can serve as a T‐recognition element, and the stereochemistry and the nature of these subunits significantly influence binding properties in these recognition events. Subunit (1R,3R)‐3‐aminocyclopentanecarboxylic acid broadens our scope to design novel polyamides.
Iatrogenic pulmonary artery rupture during Swan–Ganz catheter placement—A novel therapeutic approach
Authors: Kalra Ankur , Heitner Stephen , Topalian Simon
Published: May 2012

Pulmonary artery rupture (PAR) is a rare but deadly complication (incidence of 0.03–0.2% of all PA cannulations), with mortality in the region of 70%. We report a case of an 88‐year‐old woman with iatrogenic PAR as a result of Swan–Ganz catheter placement. A rapid successful isolation and occlusion of the culprit PA branch via the deployment of an Amplatzer® Vascular Plug (AGA Medical Corporation, North Plymouth, MN) was performed. To our knowledge, this is the first case report where this device has been used as therapy in PAR. © 2012 Wiley Periodicals, Inc.
Constructing Organic D–A–π‐A‐Featured Sensitizers with a Quinoxaline Unit for High‐Efficiency Solar Cells: The Effect of an Auxiliary Acceptor on the Absorption and the Energy Level Alignment
Authors: Pei Kai , Wu Yongzhen , Wu Wenjun , Zhang Qiong , Chen Baoqin , Tian He , Zhu Weihong
Published: May 2012

Four organic D–A–π‐A‐featured sensitizers (TQ1, TQ2, IQ1, and IQ2) have been studied for high‐efficiency dye‐sensitized solar cells (DSSCs). We employed an indoline or a triphenylamine unit as the donor, cyanoacetic acid as the acceptor/anchor, and a thiophene moiety as the conjugation bridge. Additionally, an electron‐withdrawing quinoxaline unit was incorporated between the donor and the π‐conjugation unit. These sensitizers show an additional absorption band covering the broad visible range in solution. The contribution from the incorporated quinoxaline was investigated theoretically by using DFT and time‐dependent DFT. The incorporated low‐band‐gap quinoxaline unit as an auxiliary acceptor has several merits, such as decreasing the band gap, optimizing the energy levels, and realizing a facile structural modification on several positions in the quinoxaline unit. As demonstrated, the observed additional absorption band is favorable to the photon‐to‐electron conversion because it corresponds to the efficient electron transitions to the LUMO orbital. Electrochemical impedance spectroscopy (EIS) Bode plots reveal that the replacement of a methoxy group with an octyloxy group can increase the injection electron lifetime by a factor of 2.4. IQ2 and TQ2 can perform well without any co‐adsorbent, successfully suppress the charge recombination from TiO2 conduction band to I3− in the electrolyte, and enhance the electron lifetime, resulting in a decreased dark current and enhanced open circuit voltage (Voc) values. By using a liquid electrolyte, DSSCs based on dye IQ2 exhibited a broad incident photon‐to‐current conversion efficiency (IPCE) action spectrum and high efficiency (η=8.50 %) with a short circuit current density (Jsc) of 15.65 mA cm−2, a Voc value of 776 mV, a fill factor (FF) of 0.70 under AM 1.5 illumination (100 mW cm−2). Moreover, the overall efficiency remained at 97 % of the initial value after 1000 h of visible‐light soaking.