bluuebunny/crossref_metadata_2025_split huggingface dataset:
Limited utility of acetoxymethyl (AM)‐based intracellular delivery systems, in vivo: interference by extracellular esterases
Authors: JOBSIS PAUL D. , ROTHSTEIN EMILY C. , BALABAN ROBERT S. 
Published: September 2010

SummaryThe use of acetoxymethyl (AM) groups to deliver and trap exogenous optical probes inside cells is an established tool in cell biology/physiology, however, these probes have not been used extensively in vivo. In this study, the use of the acetoxymethyl delivery system for optical probes was evaluated, in vivo. Initial studies revealed very little trapped probe in intact tissues even when near saturating levels of probe were injected in living animals. We tested the hypothesis that extracellular esterases rapidly cleave the acetoxymethyl groups preventing the probes from entering cells, in vivo. The rates of hydrolysis of 11 acetoxymethyl probes in diluted porcine plasma revealed an essentially first order high rate dye cleavage with half times on the order of minutes or less. Studies on mice and rabbits revealed rates 10‐ to 2‐fold higher, respectively. These plasma studies suggested that the acetoxymethyl probes were being cleaved before having a chance to enter cells in tissues in vivo. This was confirmed using intravital 2‐photon excitation microscopy in muscle tissue where several acetoxymethyl probes were found to rapidly cleave in the vascular space during infusion and not be trapped in the muscle cells. Studies with succinimidyl esters that should quickly bind to proteins on cleavage also failed to enter cells, in vivo, consistent with the notion that the cleavage was occurring in the extracellular space. These data suggest that the high level of plasma and extracellular esterase activity render the classical acetoxymethyl probes ineffective for monitoring intracellular events, in vivo. Different approaches to trapping exogenous probes will need to be explored for physiological studies using intravital microscopy.
Limitation in obtainable surface roughness of hardened cement paste: ‘virtual’ topographic experiment based on focussed ion beam nanotomography datasets
Authors: TRTIK P. , DUAL J. , MUENCH B. , HOLZER L. 
Published: September 2010

SummarySurface roughness affects the results of nanomechanical tests. The surface roughness values to be measured on a surface of a porous material are dependent on the properties of the naturally occurring pore space. In order to assess the surface roughness of hardened cement paste (HCP) without the actual influence of the usual sample preparation for nanomechanical testing (i.e. grinding and polishing), focussed ion beam nanotomography datasets were utilized for reconstruction of 3D (nanoscale resolution) surface profiles of hardened cement pastes. ‘Virtual topographic experiments' were performed and root mean square surface roughness was then calculated for a large number of such 3D surface profiles. The resulting root mean square (between 115 and 494 nm) is considerably higher than some roughness values (as low as 10 nm) reported in the literature. We suggest that thus‐analysed root mean square values provide an estimate of a ‘hard’ lower limit that can be achieved by ‘artefact‐free’ sample preparation of realistic samples of hardened cement paste. To the best of our knowledge, this ‘hard’ lower limit was quantified for a porous material based on hydraulic cement for the first time. We suggest that the values of RMS below such a limit may indicate sample preparation artefacts. Consequently, for reliable nanomechanical testing of disordered porous materials, such as hardened cement paste, the preparation methods may require further improvement.
Real‐time three‐dimensional imaging of cell division by differential interference contrast microscopy
Authors: TSUNODA M. , ISAILOVIC D. , YEUNG E.S. 
Published: September 2010

SummaryDifferential interference contrast (DIC) microscopy can provide information about subcellular components and organelles inside living cells. Applicability to date, however, has been limited to 2D imaging. Unfortunately, understanding of cellular dynamics is difficult to extract from these single optical sections. We demonstrate here that 3D differential interference contrast microscopy has sub‐diffraction limit resolution both laterally and vertically, and can be used for following Madin Darby canine kidney cell division process in real time. This is made possible by optimization of the microscope optics and by incorporating computer‐controlled vertical scanning of the microscope stage.
New advances in the 3D characterization of mineral coating layers on paper
Authors: CHINGA‐CARRASCO G. , KAUKO H. , MYLLYS M. , TIMONEN J. , WANG B. , ZHOU M. , FOSSUM J. O. 
Published: September 2010

SummaryThe surface characteristics of a large set of commercial lightweight coated paper grades are explored. The quantification of the 3D structure is revealed by atomic force microscopy, laser profilometry and X‐ray microtomography. This comprehensive study demonstrates the suitability of different and modern methods for assessing critical coating layer properties, thus identifying the right tools for specific structural analyses. Based on the assessment of the top and bottom surfaces of 25 commercial lightweight coated samples, three main conclusions can be drawn: (1) the facet orientation polar angle is a function of roughness, (2) skewness did not describe the surface details affecting the gloss of the commercial lightweight coated samples assessed in this study and (3) surface roughness at wavelengths below approximately 1.0 μm does not affect the paper gloss significantly. This is important knowledge for the understanding of lightweight coated paper surface structure and its properties.
Differential aberration correction (DAC) microscopy: a new molecular ruler
Authors: VALLOTTON P. 
Published: September 2010

SummaryConsiderable efforts have been deployed towards measuring molecular range distances in fluorescence microscopy. In the 1–10 nm range, Förster energy transfer microscopy is difficult to beat. Above 300 nm, conventional diffraction limited microscopy is suitable. We introduce a simple experimental technique that allows bridging the gap between those two resolution scales in both 2D and 3D with a resolution of about 20 nm. The method relies on a computational approach to accurately correct optical aberrations over the whole field of view. The method is differential because the probes of interest are affected in exactly the same manner by aberrations as are the reference probes used to construct the aberration deformation field. We expect that this technique will have significant implications for investigating structural and functional questions in bio‐molecular sciences.
Three‐dimensional shapes and spatial distributions of Pt and PtCr catalyst nanoparticles on carbon black
Authors: GONTARD L. CERVERA , DUNIN‐BORKOWSKI R.E. , OZKAYA D. 
Published: September 2010

SummaryHigh‐angle annular dark‐field scanning transmission electron microscopy tomography is applied to the study of Pt and PtCr nanoparticles supported on carbon black, which are used as heterogeneous catalysts in the electrodes of proton exchange membrane fuel cells. By using electron tomography, the three‐dimensional architecture of the heterogeneous catalyst system can be determined, providing high‐spatial‐resolution information about the shapes, faceting and crystallographies of 5–20 nm single and multiply twinned catalyst particles, as well as their positions with respect to the carbon support. Approaches that can be used to provide improved information about the distribution and orientation of the particles on their support are proposed and discussed. Our results show that electron tomography provides important information that is complementary to high‐resolution lattice imaging. Both techniques are required to understand fully the nature and role of the surfaces of faceted catalyst particles.
A pixel‐based likelihood framework for analysis of fluorescence recovery after photobleaching data
Authors: JONASSON J.K. , LORÉN N. , OLOFSSON P. , NYDÉN M. , RUDEMO M. 
Published: September 2010

SummaryA new framework for the estimation of diffusion coefficients from data on fluorescence recovery after photobleaching (FRAP) with confocal laser scanning microscopy (CLSM) is presented. It is a pixel‐based statistical methodology that efficiently utilizes all information about the diffusion process in the available set of images. The likelihood function for a series of images is maximized which gives both an estimate of the diffusion coefficient and a corresponding error. This framework opens up possibilities(1)to obtain localized diffusion coefficient estimates in both homogeneous and heterogeneous materials,(2)to account for time differences between the registrations at the pixels within each image, and(3)to plan experiments optimized with respect to the number of replications, the number of bleached regions for each replicate, pixel size, the number of pixels, the number of images in each series etc. To demonstrate the use of the new framework, we have applied it to a simple system with polyethylene glycol (PEG) and water where we find good agreement with diffusion coefficient estimates from NMR diffusometry. In this experiment, it is also shown that the effect of the point spread function is negligible, and we find fluorochrome‐concentration levels that give a linear response function for the fluorescence intensity.
Scanning electron microscope electron detector with a radial type discrete dynode electron multiplier
Authors: HEJNA J. 
Published: September 2010

SummaryA discrete dynode electron multiplier with radial flux of electrons was built and tested in the range of low‐voltage scanning electron microscopy as a backscattered electron detector of topographic contrast. The multiplier collects backscattered electron emitted in a specific range of take‐off angles and over the whole azimuth angular range enabling large solid collection angle. Multipliers with different dynode shapes were studied theoretically with the use of the software for particle optics and three assemblies were built and tested experimentally. The gain estimation, assessment of the type of detected electrons (secondary electron or backscattered electron), imaging the spatial collection efficiency and signal‐to‐noise measurements were performed.
Comparison and accuracy of methods to determine the confocal volume for quantitative fluorescence correlation spectroscopy
Authors: RÜTTINGER S. , BUSCHMANN V. , KRÄMER B. , ERDMANN R. , MACDONALD R. , KOBERLING F. 
Published: September 2010

SummarySingle molecule detection based on fluorescent labels offers the possibility to gain not only qualitative but also quantitative insight into specific functions of complex biological systems. Fluorescence correlation spectroscopy is one of the favourite techniques to determine concentrations and diffusion constants as well as molecular brightness of molecules in the pico‐ to nano‐molar concentration range, with broad applications in biology and chemistry. Although fluorescence correlation spectroscopy in principle has the potential to measure absolute concentrations and diffusion coefficients, the necessity to know the exact size and shape of the confocal volume very often hampers the possibility to obtain quantitative results and restricts fluorescence correlation spectroscopy to relative measurements mainly. The determination of the confocal volume in situ is difficult because it is sensitive to optical alignment and aberrations, optical saturation and variations of the index of refraction as observed in biological specimen. In the present contribution, we compare different techniques to characterize the confocal volume and to obtain the confocal parameters by fluorescence correlation spectroscopy curve fitting, a fluorescence correlation spectroscopy dilution series and confocal scanning of fluorescent beads. The results are compared in the view of quantitative fluorescence correlation spectroscopy measurement and analysis. We investigate how unavoidable artefacts caused by a non‐ideal confocal volume can be experimentally determined and validated.
Electroantennogram responses of a parasitic wasp, Microplitis croceipes, to host‐related volatile and anthropogenic compounds
Authors: Park Kye Chung , Zhu Junwei , Harris Jennifer , Ochieng Samuel A. , Baker Thomas C. 
Published: September 2010

SummaryThe parasitic wasp Microplitis croceipes (Cresson) (Hymenoptera: Braconidae) showed its own characteristic electroantennogram (EAG) response profiles to 13 host‐related (cis‐3‐hexenol, α‐pinene (R)‐(+)‐limonene (S)‐(–)‐limonene, trans‐β‐ocimene (±)‐linalool, (–)‐trans‐caryophyllene, α‐humulene, nerolidol, trans‐nerolidol, cis‐nerolidol, methyl jasmonate and indole) and four anthropogenic (2‐diisopropylaminoethanol, 2,2′‐thiodiethanol, 2‐methyl‐5‐nitroaniline and cyclohexanone) volatile compounds. These profiles were similar between males and females except for 2‐diisopropylaminoethanol, which elicited significantly larger EAG responses in males. Among the compounds tested, cis‐3‐hexenol, linalool and cyclohexanone elicited the largest EAG responses. EAG responses were not influenced by the age of wasps between 1 and 13 days after emergence. EAG responses were dose‐dependent, and highly EAG‐active compounds elicited significant EAG responses with less than 10 μg of the compounds at source. Quantification of compounds released from an odour cartridge indicates that release rate is highly dependent on the chemical nature of stimuli, showing up to 10 000‐fold differences in the amount released between different compounds when the same amount was loaded in the odour cartridge. Wasps having undergone a behavioural training regime to be attracted to either cyclohexanone or methyl jasmonate did not show any differences in EAG responses from those of untrained wasps.
Oral and vaginal epithelial cell anti‐Candida activity is acid labile and does not require live epithelial cells
Authors: Yano J. , Lilly E. A. , Steele C. , Fortenberry D. , Fidel P. L. 
Published: September 2010

Background:  Candida albicans is the causative agent of oral and vaginal candidiasis. Innate host defenses against C. albicans are important against each infection. Among these are oral and vaginal epithelial cells that have anti‐Candida activity. The mechanism of action includes a requirement for cell contact with no role for soluble factors, and a putative role for carbohydrates based on the sensitivity of the activity to periodic acid.Methods:  Periodic acid treatment of epithelial cells as well as the property of partial resistance of antifungal activity to fixation was used to further dissect the mechanism of action.Results:  The results herein effectively now challenge a role for carbohydrates alone. Firstly, the putative carbohydrate(s) released into supernatants of periodic acid‐treated epithelial cells could not compete with fresh epithelial cells for activity, and equivalent abrogation of activity was observed by periodic acid‐treated cells irrespective of the amount of carbohydrate released. Instead, the similar abrogation of activity following treatment with other acids or when cocultured under acidic conditions suggests that the activity is acid‐labile. Finally, while activity requires intact epithelial cells, it does not require live cells; activity was minimally affected by fixing epithelial cells prior to coculture where the majority of cells remained impermeable to Trypan blue but were defined as non–viable by positive nuclear staining with propidium iodide.Conclusion:  These results suggest that antifungal activity is dependent on contact by intact, but not necessarily live, epithelial cells through an acid‐labile mechanism.
Microbicidal efficacy of ozonated water against Candida albicans adhering to acrylic denture plates
Authors: Arita M. , Nagayoshi M. , Fukuizumi T. , Okinaga T. , Masumi S. , Morikawa M. , Kakinoki Y. , Nishihara T. 
Published: September 2010

Background/aims:  Ozone is known to act as a strong antimicrobial agent against bacteria, fungi, and viruses. We examined the effect of ozonated water on Candida albicans on acrylic denture plate.Methods:  The heat‐cured acrylic resins were cultured with C. albicans. After treatment of flowing ozonated water, the number of attached C. albicans was counted. In some experiments, the test samples were treated with ozonated water in combination with ultrasonication.Results:  After exposure to flowing ozonated water (2 or 4 mg/l) for 1 min, viable C. albicans cells were nearly nonexistent. The combination of ozonated water and ultrasonication had a strong effect on the viability of C. albicans adhering to the acrylic resin plates. There were no significant differences in antimicrobial activity against C. albicans between plates immersed in ozonated water with ultrasonication and those treated with commercially available denture cleaners. In addition, electron microscopic analysis revealed that small amounts of C. albicans remained on the plate after exposure to flowing ozonated water or immersion in ozonated water with ultrasonication.Conclusion:  Our results suggest that application of ozonated water may be useful in reducing the number of C. albicans on denture plates.
A new checkerboard panel for testing bacterial markers in periodontal disease
Authors: Dahlén G. , Leonhardt Å. 
Published: September 2010

Background/aims:  Various microbiological methods have been used for testing bacterial markers for periodontitis and periodontal disease progression. Most studies have used only a limited number of well recognized bacterial species. The purpose of the present study was to evaluate the association of 13 more recently identified bacterial species in a new panel in comparison with 12 previously more recognized periodontotopathogens (‘old panel’) using the ‘checkerboard’ DNA–DNA hybridization method.Methods:  Fifty individuals were chosen who showed at least one site with a probing pocket depth of 6 mm or more (disease) and bleeding on probing and at least one site with a probing pocket depth of 3 mm and without bleeding on probing (health). One diseased and one healthy site on each individual were sampled with the paperpoint technique and the samples were processed in the checkerboard technique against deoxigenin‐labeled whole genomic probes to 25 subgingival species representing 12 well recognized and 13 newly identified periodontitis associated species.Results:  Twenty‐four (out of 25) species were detected more frequently in the subgingival plaque of diseased than healthy sites both at score 1 (> 104) and score 3 (> 105). A significant difference at the higher score (score 3) was noticed for all species of the old panel except for three (Streptococcus intermedius, Selenomonas noxia, and Eikenella corrodens). Of the species in the new panel only Prevotella tannerae, Filifactor alocis, and Porphyromonas endodontalis showed a statistical significant difference between diseased and healthy sites.Conclusion:  It was concluded that P. tannerae, F. alocis, and P. endodontalis should be added to the 12 species used for routine diagnostics of periodontitis‐associated bacterial flora.
Cytokine pattern determines the progression of experimental periodontal disease induced by Actinobacillus actinomycetemcomitans through the modulation of MMPs, RANKL, and their physiological inhibitors
Authors: Garlet G. P. , Cardoso C. R. , Silva T. A. , Ferreira B. R. , Ávila‐Campos M. J. , Cunha F. Q. , Silva J. S. 
Published: September 2010

Objective:  Inflammatory and immune reactions raised in response to periodontopathogens are thought to trigger periodontal tissue destruction. We therefore investigated the expression of matrix metalloproteinases (MMPs) and the osteoclastogenic factor RANKL (receptor activator of nuclear factor‐κB ligand), their respective inhibitors TIMPs (tissue inhibitors of metalloproteinases) and OPG (osteoprotegerin) and their possible correlation with the expression of inflammatory and regulatory cytokines in the course of experimental periodontal disease in mice.Methods:  We characterized the time course of leukocyte migration and alveolar bone loss in C57BL/6 mice infected with Actinobacillus actinomycetemcomitans. Quantitative polymerase chain reaction (RealTime PCR) and ELISA were performed to determine the expression of MMPs, TIMPs, RANKL, OPG and cathepsin K, interleukin‐1β, tumor necrosis factor‐α, interferon‐γ, interleukin‐12, interleukin‐4 and interleukin‐10 in periodontal tissue samples harvested throughout the course of experimental disease.Results:  Oral inoculation of A. actinomycetemcomitans results in an intense and widespread migration of leukocytes to the gingival tissues, besides marked alveolar bone resorption. Our data also demonstrate two distinct patterns of MMP/TIMP and RANKL/OPG expression in the course of experimental periodontal disease. The expression of MMPs (MMP‐1, 2 and 9) and RANKL was correlated with the expression of interleukin‐1β, tumor necrosis factor‐α and interferon‐γ, in a time period characterized by the intense increase of inflammatory reaction and alveolar bone loss. On the other hand, interleukin‐4 and interleukin‐10 were associated with higher expression of TIMPs (TIMP 1, 2 and 3) and OPG, with a lower expression of MMPs and RANKL, and with reduced rates of increase of cellular infiltration in periodontal tissues and alveolar bone loss.Conclusions:  It is possible that the pattern of cytokines produced in periodontal tissues determines the progression and the severity of experimental periodontal disease, controlling the breakdown of soft and bone tissues through the balance between MMPs/TIMP and RANKL/OPG expression in gingival tissues.
Relationship between Campylobacter rectus and periodontal status during pregnancy
Authors: Yokoyama M. , Hinode D. , Yoshioka M. , Fukui M. , Tanabe S. , Grenier D. , Ito H.‐O. 
Published: September 2010

Introduction:  In a previous study, we showed that the growth of Campylobacter rectus is stimulated by the presence of female sex hormones in the culture medium. In the present study, we examined the relationship between C. rectus levels in the saliva and the periodontal status of pregnant women.Methods:  Unstimulated whole saliva was collected from 22 pregnant and 15 non‐pregnant women. Periodontal pocket depth (PD) and bleeding on probing (BOP) were recorded. A quantitative real‐time polymerase chain reaction was performed to determine the concentrations of suspected periodontopathogenic bacteria in the saliva samples. In addition, the concentration of estradiol in the saliva samples was measured by enzyme immunoassay.Results:  The average age, number of teeth, and total number of bacteria in the saliva of subjects in both groups were similar. The percentage of sites with a PD = 4 mm and the salivary estradiol concentrations were significantly higher in pregnant women than in non‐pregnant women. In addition, the percentage of BOP sites and the C. rectus levels in the saliva of the pregnant women tended to be higher than in non‐pregnant women, although these differences were not statistically significant. There were positive correlations between C. rectus levels and estradiol concentrations, and between C. rectus levels and the percentage of sites with PD = 4 mm in the pregnant women.Conclusion:  These results indicate that C. rectus levels are higher in the oral flora of pregnant women and that this may be associated with increased salivary estradiol concentrations. This may contribute to periodontal disease progression during pregnancy.