bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gel‐to‐gel phase transition may occur in mammalian cells: Mechanism of formation of “dark” (compacted) neurons
Authors: Gallyas Ferenc , Farkas Orsolya , Mázló Mária 
Published: January 2012

Summry— In the course of many diseases, individual non‐apoptotic cells that are randomly distributed among undamaged cells in various mammalian tissues become shrunken and hyperbasophilic (“dark”). The light microscopic shrinkage is caused by a potentially reversible, dramatic compaction of all ultrastructural elements inside the affected cells, and escape of the excess water through apparently intact plasma membrane. In the case of neurons, the ultrastructural compaction rapidly involves the soma‐dendrite domains in an all‐or‐nothing manner, and also mm‐long axon segments. The present paper demonstrates that such ultrastructural compaction in neurons, which affects the whole soma‐dendrite domain or long axon segments, can take place both immediately after an in vivo head injury and in rat brains perfusion‐fixed for 30 min., and then chilled to just above the freezing point before the same kind of head injury was inflicted. This argues strongly against any enzyme‐mediated compaction mechanism. On the analogy of gel‐to‐gel phase transitions in polymer chemistry, we hypothesize a pure physico‐chemical compaction mechanism. Specifically, after initiation at a single site in each affected cell, the ultrastructural compaction is propelled throughout the whole cell on the domino principle by the free energy stored in the form of non‐covalent interactions among the constituents of some cytoplasmic gel structure.
AGS proteins, GPR motifs and the signals processed by heterotrimeric G proteins
Authors: Lanier Stephen M 
Published: January 2012

Summry— A long term objective of our research effort is to define factors that influence the specificity and efficiency of signal propagation by heterotrimeric G‐proteins (G). G‐proteins play a central role in cellular communication mediating the cell response to numerous hormones and neurotransmitters. A major determinant of signalling specificity for heterotrimeric G‐proteins is the cell specific expression of the subtypes of the primary signalling entities, receptor, G and effector (E). Another major site for regulating signalling specificity lies at the R‐G or G‐E interface where these interactions are influenced by cell architecture, the stoichiometry of signalling components and accessory proteins that may segregate the receptor to microdomains of the cell, regulate the efficiency and/or specificity of signal transfer and/or influence the activation state of G‐protein independent of a classical G‐protein coupled receptor. One strategy to address these issues in our laboratory involves the identification of cellular proteins that regulate the transfer of signal from receptor to G or directly influence the activation state of G independent of a classical G‐protein coupled receptor. We identified three proteins, AGS1, AGS2 and AGS3 (for Activators of G‐protein Signaling), that activated heterotrimeric G‐protein signalling pathways in the absence of a typical receptor. AGS1, 2 and 3 interact with different subunits and/or conformations of heterotrimeric G‐proteins, selectively activate different G‐proteins, provide unexpected mechanisms for regulation of the G‐protein activation cycle and have opened up a new area of research related to the cellular role of G‐proteins as signal transducers.
Pillared metal(IV) phosphate-phosphonate extraction of actinides
Authors: Burns J. D. , Clearfield A. , Borkowski Marian , Reed Donald T. 
Published: January 2012

Abstract
Four pillared metal(IV) phosphate-phosphonate ion exchange materials were synthesized and characterized. Studies were conducted to determine their affinity for the lanthanides (Ln´s) and actinides (An´s). It was determined that by simply manipulating the metal source (Zr or Sn) and the phosphate source (H3PO4 or Na3PO4) large differences were seen in the extraction of the Ln and An species. K
d values higher than 4×105 were observed for the AnO2
2+ species in nitric acid at pH 2. These basic uptake experiments are important, as the data they provide may indicate the possibility of a separation of Ln´s from An´s or even more notably americium from curium and Ln´s.
Optical Trapping, Biosensing, and Spectroscopy in a Single Plasmonic Platform
Authors: Cetin Arif E. , Yilmaz Cihan , Yanik Ahmet , Somu Sivasubramanian , Busnaina Ahmed , Altug Hatice 
Published: January 2012

ABSTRACTWe propose plasmonic platform that can enable optical trapping, spectroscopy and biosensing, all in the same platform. The system is based on periodic arrays of gold nanopillars fabricated on a supporting gold layer. The proposed platform is highly desirable for biosensing applications since it supports highly refractive index sensitivities as large as 675 nm/RIU which. The spectrally sharp resonances provides large figure of merits as large as 112.5. As the nanopillar array supports large near-field intensities accessible to the biomolecules in the sample around the platform, as large as 10.000 times, the proposed structure can be used for surface enhanced spectroscopy applications. The pillar array also supports plasmonic hot spots with high near-field intensity gradient leading to large gradient forces, 350 pN/W/μm2 which is needed for optical trapping applications.
One-Step Synthesis of Stable Gold Nanoparticles on Eco-friendly Ionic Liquid
Authors: Anantha P , Wang Xiu , Wong C.C. 
Published: January 2012

ABSTRACTMetallic nanoparticles are often obtained by chemical decomposition or reactive techniques involving the extensive usage of harmful reducing or stabilizing agents. A facile green synthesis technique resulting in readily exploitable nanoparticle dispersion in ionic liquid without the use of any additional agents is reported here. 1-Propyl- 3- Methyl Imidazolium Iodide (PMIM(I)) is a non-volatile, thermally stable and non-toxic ionic liquid. This eco-friendly liquid is used as the substrate for thermal evaporation of gold to obtain stable gold nanoparticles. On being examined by Transmission Electron Microscopy the high monodispersity in their sizes was revealed. The byproduct free, ‘clean’ processing technique helps in obtaining un-contaminated particles. The thermal evaporation method used (for the generation of metallic vapor) plays a significant role in the difference in kinetics of the formation and growth of nanoparticles, unlike the widely reported sputtering technique for vapor generation. The formed particles are deposited only on the top surface of the liquid. Thus the nucleation and growth of the particles can be considered to have occurred by surface diffusion process only. A deeper investigation into the formation kinetics has the potential application for synthesizing other nanomaterials via this environmental friendly approach.
Anodic and cathodic pre-treatment effects on BDD surface to deposit copper nanoparticles applied to nitrate reduction
Authors: Santos L. C. D. , Couto A. B. , Matsushima J. T. , Forti M.C. , Baldan M. R. , Ferreira N. G. 
Published: January 2012

ABSTRACTThe influence of anodic and cathodic pre-treatment on boron doped diamond (BDD) surface for copper (Cu) electrodeposition was studied to assess Cu particle consolidation on BDD electrode. These modified electrodes were applied to study the nitrate electrochemical reduction process. The obtained results showed that the BDD surface cathodically treated presented high Cu particle density as well as even distribution on the electrode surface after the electrodeposition process. For samples anodically treated the electrodeposited Cu was dispersed with lower particle density. This behavior was attributed to a high electrode conductivity imposed by the cathodic pre-treatment leading to an increase in the BDD surface hydrogenation. Therefore, one can conclude that for electrochemical nitrate reduction the anodically treated BDD has a better reproducibility. This response is attributed to the Cu particle consolidation on BDD electrode due to the oxygen surface terminations induced by the anodic pretreatment.
Copper Oxide Edge-Termination for GaN Schottky Barrier Diodes with Low Turn-on Voltage
Authors: Minoura Yuichi , Okamoto Naoya , Kanamura Masahito , Imada Tadahiro , Ohki Toshihiro , Imanishi Kenji , Watanabe Keiji , Joshin Kazukiyo , Kikkawa Toshihide 
Published: January 2012

ABSTRACTIn this study, we propose copper oxide (CuOx) edge-termination for GaN-based Schottky barrier diodes (SBDs) with low turn-on voltage. CuOx fabricated by thermal oxidization of sputtered Cu film at 275°C consisted mainly of Cu2O which is known as a p-type semiconductor. We applied CuOx edge-termination to GaN SBDs with tantalum (Ta) Schottky electrode which has low work function of 4.25 eV. The experimental results of current-voltage characteristics insisted that CuOx edge-termination structure was effective to increase breakdown voltage of GaN SBDs with keeping low turn-on voltage of 0.29 V at 10 A/cm2.
Couplings in GaAs/AlGaAs/Metal Photonic Waveguides with Metallic Variations
Authors: Shih Meng-Mu 
Published: January 2012

ABSTRACTTo have better light-emitting performance, semiconductor-metal periodic photonic waveguides can generate stable wavelengths. This work constructs a multi-parameter model to compute the backward-wave mode-coupling coefficients, which are important to the analysis and performance of photonic devices. For such a semiconductor-metal hybrid structure, a proper photonic technique needs to be utilized to solve this computational complexity.Numerical results demonstrate how the materials of metal gratings, the corrugation amplitudes of metal gratings, and the metallic aluminum mole fraction can affect the coupling coefficients. Further physical interpretation and discussion can support and explain the above results. The results can help engineers decide the values of parameters used in fabrication. Future work and applications will be proposed.
Infrared ellipsometry and near-infrared-to-vacuum-ultraviolet ellipsometry study of free-charge carrier properties in In-polar p-type InN
Authors: Schöche Stefan , Hofmann Tino , Ben Sedrine Nebiha , Darakchieva Vanya , Wang Xinqiang , Yoshikawa Akihiko , Schubert Mathias 
Published: January 2012

ABSTRACTWe apply infrared spectroscopic ellipsometry (IRSE) in combination with near-infrared to vacuum-ultraviolet ellipsometry to study the concentration and mobility of holes in a set of Mg-doped In-polar InN samples of different Mg-concentrations. P-type behavior is found in the IRSE spectra for Mg-concentrations between 1x1018 cm-3 and 3x1019 cm-3. The free-charge carrier parameters are determined using a parameterized model that accounts for phonon-plasmon coupling. From the NIR-VUV data information about layer thicknesses, surface roughness, and structural InN layer properties are extracted and related to the IRSE results.
Population Biology and Natural History ofParides burchellanus(Papilionidae: Papilioninae: Troidini), an Endangered Brazilian Butterfly
Authors: Beirão Marina V , Campos-Neto Fernando C , Pimenta Ivan A , Freitas André V L 
Published: January 2012

AbstractThe present paper describes the population parameters, the behavior, and the geographic range of Parides burchellanus (Westwood, 1872), an endangered papilionid butterfly from Brazil. Population biology was described based on a 13-mo mark-recapture program in a site of riparian forest in Minas Gerais, southeastern Brazil. The range of the population size was 10–30 individuals (with a maximum near 100 individuals). Sex ratio was male biased, with males dominating in all months. The age structure was not stable, with an increase in intermediate and old individuals before the population break in the dry season. The residence time was 23.2 ± 18.4 d for males and 16.4 ± 12.5 to females, with a maximum of 73 d recorded for males and 64 d for females. Males can travel distances of up to 950 m and females up to 650 m. When searching for P. burchellanus populations in 63 sites with suitable habitats, only seven actually had resident populations. A combination of high habitat specificity for larvae and adults could explain the rarity of this butterfly. The available data could be used in conservation programs for P. burchellanus, which should include protection of the habitats of all known colonies so far.
Structural Examination of the Dufour's Gland of the Solitary BeesOsmia lignariaandMegachile rotundata(Hymenoptera: Megachilidae)
Authors: Pitts-Singer Theresa L , Buckner James S , Freeman Thomas P , Guédot Christelle 
Published: January 2012

AbstractThe Dufour's gland of two solitary cavity-nesting bees, Osmia lignaria Say and Megachile rotundata (F.) (Hymenoptera: Megachilidae), was examined with microscopy to determine the structure and arrangement of the gland in the sting apparatus. The appearance and relative size of the Dufour's gland of these two bee species are similar. Unlike the termination of the Dufour's gland at the base of the sting in the honey bee, Apis mellifera L. ( Apidae), the posterior portion of the Dufour's gland in these megachilids enters into the sting bulb along with the venom duct. Within the sting bulb, the Dufour's gland is ventral to and longer than the venom duct. The following evidential findings presented here and elsewhere are in support of the hypothesis that the Dufour's gland is the source of an individual nest recognition cue in these two bee species: 1 ) the presence of a duct and exit pore at the posterior end of the Dufour's gland that may release glandular secretions, 2) the location of thick, brushy metasomal setae and the setosa membrane that could be used to apply a secretion to a substrate, and 3) the observed dragging of the tip of the abdomen during nest-marking.
Opportunistic Carnivory by Romalea microptera (Orthoptera: Acrididae)
Authors: Richardson Matthew L , Reagel Peter F , Mitchell Robert F , Whitman Douglas W 
Published: January 2012

Abstract
Grasshoppers generally are considered to be phytophagous. However, increasing evidence shows that many are better classified as omnivorous. The eastern lubber grasshopper Romalea microptera (Beauvois) (Orthoptera: Acrididae) not only consumes plants, but also dead or wounded arthropods in the field. We tested the potential range of arthropod taxa scavenged by R. microptera by offering fresh-killed carcasses to adult females in the laboratory. We predicted that they would eat all arthropods except those that the grasshopper's mandibles could not cut and chemically defended arthropods. We offered grasshoppers 104 arthropod species and life stages, representing 20 orders in five classes (Arachnida, Chilopoda, Diplopoda, Insecta, and Malacostraca). The grasshoppers completely consumed the entire body of all individuals of 42% of the arthropod species and life stages, and another 32% were highly consumed. Overall, 96% of the arthropod species and life stages, representing 19 of the 20 total orders, were consumed to some extent, suggesting that R. microptera is an opportunistic carnivore. Chemical defense in arthropods did not deter feeding by R. microptera, but the hardness of integument did: harder-bodied Hymenoptera and Coleoptera were consumed less than softer-bodied arthropods. Our results confirm that R. microptera is not strictly phytophagous, but readily eats a wide range of arthropod taxa. Carnivory within phytophagous clades may have important physiological, ecological, and evolutionary consequences.
Trichogramma pretiosum (Hymenoptera: Trichogrammatidae) Parasitism of Trichoplusia ni (Lepidoptera: Noctuidae) Eggs Under Different Temperatures
Authors: Da Silva Altoé Thiago , Pratissoli Dirceu , De Carvalho José Romário , Dos Santos Junior Hugo José Gonçalves , Pereira Paes João Paulo , De Freitas Bueno Regiane Cristina Oliveira , Bueno Adeney De Freitas 
Published: January 2012

Abstract
A study of the biological characteristics and thermal requirements of the parasitoid Trichogramma pretiosum Riley, 1879 (Hymenoptera: Trichogrammatidae) on eggs of Trichoplusia ni (Hübner, 1802) (Lepidoptera: Noctuidae) at several different temperatures was performed in this work. Eggs of T. ni were exposed to T. pretiosum strain Tspd parasitism for 5 hr and then transferred to environmentally controlled growth chambers set at the temperatures of 18, 21, 24, 27, 30, and 33 ± 1°C. The duration of the T. pretiosum egg-to-adult period was affected by temperature, varying from 6 to 18 d over the range of the studied temperatures. The number of individuals emerged per egg and the sex ratio also were affected by temperature variations, but regression analysis did not find correlation between the increase of temperature and the observed variation of these biological parameters. Similarly, parasitism viability (percentage) was influenced by temperature variation, but always exceeded 80% at all tested temperatures. The thermal lower limit of development (Tbase) and the thermal constant (K) for T. pretiosum were 11.84°C and 128.37 DD, respectively. These results here reported indicate that T. pretiosum was impacted by the temperature, however, this parasitoid had a satisfactory performance on T. ni eggs at all studied temperature (from 18 to 33°C), showing potential to be used successfully as a biological control agent of this pest in different regions that fit in this tested temperature range. Also, the rearing temperature of this parasitoid might be changed from 18 to 33°C, according to commercial demands for accelerating or retarding mass production for field releases without damages to the parasitoid development.
Fusobacterium nucleatum Biofilm Induces Epithelial Migration in an Organotypic Model of Dento‐Gingival Junction
Authors: Pöllänen Marja T. , Gursoy Ulvi K. , Könönen Eija , Uitto Veli‐Jukka 
Published: January 2012

Background: Effects of Fusobacterium nucleatum (F. nucleatum) biofilm on epithelial cell proliferation, apoptotic cell death, and basement membrane constituent collagen IV production were examined in an organotypic dento‐epithelial (OD‐E) model.Methods: The OD‐E model was constructed by seeding keratinocytes on fibroblast‐containing collagen gels and by placing tooth pieces on top. A 3‐day‐old biofilm either a laboratory strain (American Type Culture Collection [ATCC] 25586) or a clinical strain (Anaerobe Helsinki Negative [AHN] 9508) of F. nucleatum was placed on the top of the model. The coculture was incubated ≤24 hours. The expression and localization of Ki‐67, caspase‐3, and collagen IV were examined by immunohistochemistry.Results: Hematoxylin and eosin staining showed epithelial migration and lateral sprouting into the connective tissue matrix in F. nucleatum OD‐E cocultures. The proliferation pattern of the in vitro dento‐epithelial junction was changed. In controls without bacterial challenge, the Ki‐67 expression was abundant in the cells attached to the tooth, whereas in F. nucleatum biofilm‐treated cultures, the Ki‐67‐expressing cells were more often in the connective tissue‐facing side of the epithelium. An apoptotic marker caspase‐3 was expressed in controls and in F. nucleatum laboratory strain ATCC cocultures throughout the epithelium, in contrast to cultures treated with F. nucleatum clinical strain AHN, in which caspase‐3 was absent. Collagen IV stainings were negative in both controls and F. nucleatum cocultures.Conclusion: F. nucleatum biofilm coculture with OD‐E model causes lateral sprouting of the epithelium with an altered epithelial proliferation pattern, resembling the histologic changes seen in vivo in the early pathogenesis of periodontal disease.
Enamel Matrix Derivative in Intrabony Defects: Prognostic Parameters of Clinical and Radiographic Treatment Outcomes
Authors: Parashis Andreas O. , Polychronopoulou Argy , Tsiklakis Konstantinos , Tatakis Dimitris N. 
Published: January 2012

Background: The purpose of this retrospective case series study is to identify possible preoperative parameters that could predict postoperative probing depth (PD), clinical attachment level (CAL) gain, or radiographic defect resolution in intrabony defects treated with enamel matrix derivative (EMD).Methods: Sixty‐one chronic periodontitis patients, each contributing a 2‐ or 3‐wall intrabony defect treated with EMD, were included. Clinical parameters recorded included the following: PD; CAL; gingival margin position; supracrestal soft tissue (SST); surgical distances of cemento‐enamel junction (CEJ) to bone crest (CEJ‐BC), CEJ to base of the defect (CEJ‐BD), and BC to BD (BC‐BD); and depth of 2‐ and 3‐wall components. Radiographic parameters recorded included the following: CEJ‐BC, CEJ‐BD, BC‐BD distances, and radiographic defect angle. Postoperative assessments were performed at 12 months.Results: The probability of postoperative PD >4 mm increased 1.6‐fold (odds ratio [OR] = 1.6; 95% confidence interval [CI] = 1.2 to 2.3) with each 1‐mm baseline PD increase. Baseline PD and surgical CEJ‐BD were statistically significant predictors of CAL gain; the greater the baseline PD (OR = 0.5; 95% CI = 0.3 to 0.8) and bone loss (OR = 0.6; 95% CI = 0.3 to 0.9), the less likely that postoperative CAL gain was ≤3 mm. Smoking and SST were significantly associated with defect resolution; failure to achieve ≥65% defect resolution was six‐fold greater for smokers (OR = 6.5; 95% CI = 1.7 to 24.5) and almost double (OR = 1.7; 95% CI = 1.1 to 2.8) for each millimeter of SST increase.Conclusion: In EMD‐treated intrabony defects, baseline PD predicts both CAL gain and postoperative PD. Smoking and SST are predictors of defect resolution.
Effect of Priming in Subpopulations of Peripheral Neutrophils From Patients with Chronic Periodontitis
Authors: Fredriksson Margareta I. 
Published: January 2012

Background: Patients with periodontal disease are reported to generate more reactive oxygen species (ROS) than matched controls, suggesting increased inflammatory defense activity. The purpose of this study is to determine whether there are subpopulations of peripheral neutrophils in patients with chronic periodontitis (CP) that generate different levels of intracellular ROS when primed with tumor necrosis factor‐α (TNF‐α) or the chemokine interleukin‐8 (IL‐8, CXCL8) compared to controls.Methods: Venous blood was collected from 13 patients with CP despite careful maintenance over 2 to 8 years and from 13 healthy age‐ and sex‐matched controls. Neutrophils were separated from whole blood over a Percoll gradient and then activated via the Fcγ receptor with opsonized Staphylococcus aureus after priming with TNF‐α or IL‐8. The samples were analyzed by flow cytometry using the fluorescent probe dihydrorhodamine 123. Generation of ROS was measured as the intensity of fluorescence (IFL).Results: Two subpopulations were found in both patients and controls: one with low and one with high generation of IFL. The subpopulation with high generation of IFL in patients with CP was more responsive to IL‐8 (P <0.05) than the same subpopulation in healthy controls. No other differences in generation of ROS or priming effects were found between patients with CP and controls. Generation of ROS was dependent on nicotinamide adenine dinucleotide phosphate oxidase, and the intracellular ROS was primarily the oxygen anion.Conclusion: Patients with CP had a subpopulation of peripheral neutrophils that were more responsive to IL‐8 priming than controls.