ALBERT

Description: ABSTRACT We present a technique that records transient changes in the fluorescence lifetime of a sample with spatial resolution along a one-dimensional scan. The technique is based on scanning the sample with a high-frequency pulsed laser beam, detecting single photons of the fluorescence light, and building up a photon distribution over the distance along the scan, the arrival times of the photons after the excitation pulses and the time after a stimulation of the sample. The maximum resolution at which lifetime changes can be recorded is given by the line scan period. Transient lifetime effects can thus be resolved at a resolution of about one millisecond. We demonstrate the technique for recording photochemical and nonphotochemical chlorophyll transients in plants and transient changes in free Ca 2+ in cultured neurons. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: ABSTRACT Gonadotropin releasing hormone (GnRH) is a peptide that is conserved in both vertebrate and invertebrate species. In this study, we have demonstrated the distribution pattern of two isoforms of GnRH-like peptides in the neural ganglia and testis of reproductively mature male abalone , H. asinina , by immunohistochemistry and whole mount immunofluorescence. We found octopus (oct) GnRH and tunicate-I (t) GnRH-I immunoreactivities (ir) in type 1 neurosecretory cells (NS1) and they were expressed mostly within the ventral horn of the cerebral ganglion, whereas in pleuropedal ganglia they were localized primarily in the dorsal horn. Furthermore, tGnRH-I-ir were strongly detected in fibers at the caudal part of the cerebral ganglia and both ventral and dorsal horns of the pleuropedal ganglia. In the testis, only octGnRH-ir was found primarily in the granulated cell and central capillaries within the trabeculae. These results suggest that multiple GnRH-like peptides are present in the neural ganglia which could be the principal source of their production, whereas GnRH may also be synthesized locally in the testis and act as the paracrine control of testicular maturation. Microsc. Res. Tech. 77:110–119, 2014 . © 2014 Wiley Periodicals, Inc.

Description: ABSTRACT Microtubules are important targets when studying potential anticancer agents since disturbance of these microtubule dynamics results in cell cycle arrest and cell death. 2-Methoxyestradiol is a naturally occurring metabolite that exerts antiproliferative activity and induces apoptosis. Due to limited biological accessibly and rapid metabolic degradation, several analogs were synthesized. This study investigated the antiproliferative influence of an 2-methoxyestradiol analog, (8R, 13S, 14S, 17S)-2-Ethyl-13-methyl-7, 8, 9, 11, 12,13, 14, 15, 16, 17-decahydro-6H-cyclopenta[a]phenanthrane-3, 17-diyl bis(sulfamate) (EMBS) on cell proliferation, morphology and apoptosis induction in a estrogen receptor-positive breast adenocarcinoma cells line (MCF-7), estrogen receptor-negative highly metastatic breast cell line (MDA-MB-231) and a non-tumorigenic breast epithelial cell line (MCF-12A). Spectrophotometry results indicated that EMBS exerted differential antiproliferative activity in the three cell lines. Cell growth of the breast adenocarcinoma and highly metastatic breast cell line reached a plateau effect at 0.4 μM after 24 h of exposure. Light microscopy and polarization-optical transmitted light differential interference contrast demonstrated compromised cell density, cells blocked in metaphase and the presence of apoptotic characteristics after EMBS exposure for 24 h in all three cell lines. Transmission electron microscopy and scanning electron microscopy revealed hallmarks of apoptosis namely the presence of apoptotic bodies, shrunken cells and cell debris in EMBS-exposed cells. This investigation demonstrated that EMBS does exert antimitotic activity and induces apoptosis contributing to elucidating the signal transduction of EMBS in tumorigenic and non-tumorigenic breast cell lines. Findings warrant in-depth analysis of specific targets in vitro and subsequent in vivo investigation for anticancer therapy. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: ABSTRACT The sperm ultrastructure of the short-faced scorpionfly Panorpodes kuandianensis Zhong et al. was investigated using transmission electron microscopy. The spermatozoon is composed of a short head containing a bilayered acrosome and an elongate nucleus, a neck transition region, and a long flagellum. The acrosome consists of an acrosomal vesicle and a central perforatorium. The nucleus has two deep, U-shaped lateral grooves and its chromatin contains a series of parallel, regularly arrayed nuclear fibers. The barrel-shaped centriolar adjunct occupies the most volume of the neck region. The flagellum is helical for its whole length and is formed by an axoneme, two mitochondrial derivatives, a pair of accessory bodies, and peculiar accessory structures. The axoneme has nine accessory microtubules at the anterior flagellum region, displaying a 9 + 9 + 2 microtubular pattern, but the accessory microtubules are short and disappear quickly. The two mitochondrial derivatives differ in length and diameter. In the more posterior region, the remaining anchor-shaped mitochondrial derivative has a circular crystalline region, differing from other mecopteran species. The filiform materials are peculiar and lie beside the nucleus and in the flagellum region. Sperm ultrastructural comparison of P. kuandianensis with other families supports a close affinity of Panorpodidae with Panorpidae. In addition, the occurrence of the nine accessory microtubules in the sperm axoneme of Panorpodes indicates that the 9 + 9 + 2 axonemal pattern might be a symplesiomorphy of the Mecoptera. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: ABSTRACT The wing of a dragonfly is thin and light, but can bear high frequent alternating stress and present excellent antifatigue properties. The surface morphology and microstructure of the wings of dragonfly Pantala flavescens were observed using SEM in this study. Based on the biological analysis method, the configuration, morphology, and structure of the vein were studied, and the antifatigue properties of the wings were investigated. The analytical results indicated that the longitudinal veins, cross veins, and membrane of dragonfly wing form a optimized network morphology and spacially truss-like structure which can restrain the formation and propagation of the fatigue cracks. The veins with multilayer structure present high strength, flexibility, and toughness, which are beneficial to bear alternating load during the flight of dragonfly. Through tensile-tensile fatigue failure tests, the results were verified and indicate that the wings of dragonfly P. flavescens have excellent antifatigue properties which are the results of the biological coupling and synergistic effect of morphological and structural factors. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: ABSTRACT Muscle fiber images play an important role in the medical diagnosis and treatment of many muscular diseases. The number of nuclei in skeletal muscle fiber images is a key bio-marker of the diagnosis of muscular dystrophy. In nuclei segmentation one primary challenge is to correctly separate the clustered nuclei. In this article, we developed an image processing pipeline to automatically detect, segment, and analyze nuclei in microscopic image of muscle fibers. The pipeline consists of image pre-processing, identification of isolated nuclei, identification and segmentation of clustered nuclei, and quantitative analysis. Nuclei are initially extracted from background by using local Otsu's threshold. Based on analysis of morphological features of the isolated nuclei, including their areas, compactness, and major axis lengths, a Bayesian network is trained and applied to identify isolated nuclei from clustered nuclei and artifacts in all the images. Then a two-step refined watershed algorithm is applied to segment clustered nuclei. After segmentation, the nuclei can be quantified for statistical analysis. Comparing the segmented results with those of manual analysis and an existing technique, we find that our proposed image processing pipeline achieves good performance with high accuracy and precision. The presented image processing pipeline can therefore help biologists increase their throughput and objectivity in analyzing large numbers of nuclei in muscle fiber images. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: ABSTRACT Cystoisospora belli is an opportunistic protozoan that causes human cystoisosporiasis, an infection characterized by diarrhea, steatorrhea, abdominal pain, fever, and weight loss. The lack of animal models susceptible to C. belli , and the difficulty in obtaining clinical samples with fair amounts of oocysts have limited the research pertaining to the basic biology of this parasite. This study aimed to describe the ultrastructure of endogenous stages of C. belli in Monkey Rhesus Kidney Cells (MK2) and Human Ileocecal Adenocarcinoma cells (HCT-8). Zoites of C. belli exhibited typical morphological features of coccidia, which included a trilaminar pellicle, an apical complex formed by a conoid, polar rings, rhoptries, and micronemes, in addition to dense granules and the endoplasmic reticulum. No crystalloid body was observed but various lipid and amylopectin granules were usually present in the cytoplasm of zoites. We observed a tendency of the endoplasmic reticulum of the host cell to be located near the parasitophorous vacuole membrane. Merozoites were formed by endodyogeny and during replication, the apical complex of the mother cell remained intact. The formation of gametes or oocysts was not observed. The ultrastructural findings of C. belli are further evidence of its proximity to Sarcocystidae family members and corroborate their reclassification as Cystoisospora spp. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: ABSTRACT Arge pullata Zadd is an important phytophagous pest that damages red birch Betula albo-sinensis in Hubei Province, South China. Massive ecological and economic losses have been caused by this species, which threatens the ecological security of the Shennongjia Nature Reserve. To investigate the mechanoreception, chemoreception, and oviposition processes of A. pullata , scanning electron microscopy and optical confocal microscopy were used to reveal the typology, morphology, and distribution of ovipositor and antennal sensilla. The results show that A. pullata has clavate antennae and eight types of sensilla in total, including sensilla chaetica, sensilla trichodea (types 1–3), sensilla basiconica, sensilla coeloconica (types 1 and 2), and Böhm's bristles. Sensilla trichodea type 1 distributed only on male antennae; the densities of sensilla trichodea type 2 and sensilla basiconica differed between the sexes. The binding pattern of ovipositor valvulae was discovered, and one type of sensilla chaetica, two types of sensory pits, and tooth-like cones as well as two types of microtrichia were found in the ovipositor. Based on morphological evidence and research on Hymenoptera, putative functions are suggested to increase our understanding of the mechanisms by which this species finds hosts and mates, and how oviposition takes place. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: ABSTRACT The longicorn beetle Xylotrechus grayii (White, 1855) has been spreading rapidly in China, causing mass mortality of honeysuckle which is economically and medicinally important. In order to elucidate the mechanisms of mate and host location and to advance efficient control methods, antennal sensilla features were investigated in both sexes of X. grayii using scanning electron microscopy (SEM). The filiform antennae of both sexes consist of scape, pedicel, and nine flagellomeres (f1–9). Five types of sensilla were observed: sensilla chaetica (5 subtypes, SC1–5), sensilla basiconica (4 subtypes, SB1–4), Böhm bristles (Bm), grooved peg sensilla (Gp), and sensilla campaniformia (Ca). SC were most common on the antennae, followed by SB and Bm. No significant sexual differences in the type, amounts, and distribution of antennal sensilla were found except for the distribution of SB clusters and Ca. SB clusters and Ca occurred on f1–8 of male antennae but were absent on those segments in females, suggesting a potential function as receptors for female sex pheromones. The putative functions of other sensilla are discussed based on their characteristics in related species. This study provides an important foundation for further research on sensory mechanisms and control measures of X. grayii . Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: ABSTRACT In mammals, the cerebral cortex microvasculature (CCM) of the neopallium plays important roles in the physiological and pathological processes of the brain. The aim of the present work is to analyze the CCM by use of the SEM-vascular corrosion cast technique, and to examine the immunocytochemical characteristics of the CCM in adult domestic ruminants (cattle, buffalo, and sheep) by using the SEM-immunogold technique. The CCM originated from the very small, finger-like terminal branches of the macrovasculature of the brain. The superficial cortical arterioles were more numerous than the deep straight arterioles which proceeded toward the white matter. The surface casts of the arterioles and capillaries of the cerebral cortex showed ring-shaped formations in the arterioles and at the origin of the capillaries. All capillaries down-stream from these ring-shaped formations were flaccid. Casts of the capillaries showed wrinkles due to the presence of endothelial folds, which is characteristic of varying blood pressure. Formations having intense anti-GIFAP immunoreactivity were frequently evident along the course of the blood capillaries in the cerebral cortex. These formations were probably astrocytes that might regulate the cerebral microcirculation based on physiological and pathological stimuli, such as neuronal activation. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: ABSTRACT The effects of anti-angiogenic therapies in guiding tumor angioarchitecture prompted us to examine the modifications in the vascular network of the oral squamous cell carcinoma (SCC) produced by the multitargeted tyrosine kinase inhibitor sunitinib malate. Twelve Syrian hamsters had their right buccal pouches submitted to tumor induction with dimethylbenzanthracene and carbamide peroxide for 55 days. The animals were then divided into two groups of six animals each; group I was treated with sunitinib malate and group II (control) was remained untreated. After 4 weeks, the hamsters had their vascular networks casted by Mercox ® resin and analyzed by scanning electron microscopy. The qualitative study of the vascular network of the control tumor-bearing pouches showed images of intussusception and sprouting angiogenesis, flattened blood vessels, abrupt variations in their diameter, and a tortuous course. The samples treated with sunitinib exhibited a qualitative reduction of the signs of vascular proliferation. In addition, these casts presented an attenuation of the morphological features observed in the untreated tumor-bearing pouches. Quantitative analysis demonstrated that the pouches treated with sunitinib did not show a decrease ( P 〉 0.05) in the vascular diameter and intervessel distances when compared with the control group. The results of the present study suggest that sunitinib may act on the vascular network of oral SCC, normalizing the blood vessels. However, further experiments should be performed in order to determine a judicious dose of this anti-angiogenic therapy. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: ABSTRACT Due to its expansion, agriculture has become increasingly dependent on the use of pesticides. However, the indiscriminate use of insecticides has had additional effects on the environment. These products have a broad spectrum of action, and therefore the insecticide affects not only the pests but also non-target insects such as bees, which are important pollinators of agricultural crops and natural environments. Among the most used pesticides, the neonicotinoids are particularly harmful. One of the neonicotinoids of specific concern is thiamethoxam, which is used on a wide variety of crops and is toxic to bees. Thus, this study aimed to analyze the effects of this insecticide in the midgut and Malpighian tubule cells of Africanized Apis mellifera . Newly emerged workers were exposed until 8 days to a diet containing a sublethal dose of thiamethoxam equal to 1/10 of LC 50 (0.0428 ng a.i./l L of diet). The bees were dissected and the organs were processed for transmission electron microscopy. The results showed that thiamethoxam is cytotoxic to midgut and Malpighian tubules. In the midgut, the damage was more evident in bees exposed to the insecticide on the first day. On the eighth day, the cells were ultrastructurally intact suggesting a recovery of this organ. The Malpighian tubules showed pronounced alterations on the eighth day of exposure of bees to the insecticide. This study demonstrates that the continuous exposure to a sublethal dose of thiamethoxam can impair organs that are used during the metabolism of the insecticide. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: ABSTRACT Autofocusing technology is indispensable for routine use of microscopes on a large scale in biological field. The autofocusing method using the angle of Hilbert space is brought forward to measure whether the image is focused or not. The angle of Hillbert space can be used to evaluate accurately the similarity degree of two images. The experiment results show that the autofocusing method can decrease the computational cost and get accuracy for real-time biological and biomedical images with noise robustness. The focus curves are smooth and possess the unimodality, the monotonicity and the symmetry. Compared with other classic and optimum focus method, the Hilbert method demonstrates its robustness to noise and can improve the focus speed. The experiments showed that the proposed method can increase the overall performance of an autofocus system and has strong applicability in various autofocusing algorithms. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: ABSTRACT The structure of ovary in a representative of the scale insect family Matsucoccidae, Matsucoccus pini , is described at the ultrastructural level. The paired ovaries of M. pini are composed of about 50 ovarioles of telotrophic type that develop asynchronously. An individual ovariole consists of an anterior tropharium (trophic chamber) and posterior vitellarium. The tropharium encloses trophocytes (nurse cells) and early previtellogenic oocytes termed arrested oocytes. In the vitellarium from 1 to 6, linearly arranged oocytes may develop. Analysis of serial sections has shown that each ovariole contains 32 germ cells (trophocytes, arrested oocytes, and developing oocytes). In the cytoplasm of all these cells, small rod-shaped bacteria are present. In the early vitellogenic oocytes, accessory nuclei arise. As vitellogenesis progresses, these nuclei migrate toward the cortical ooplasm. The obtained results are discussed in a phylogenetic context. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: ABSTRACT Many species that belong to Artiodactyls order show an interdigital sinus (IS), as it occurs in sheep, in all four extremities. These are considered to be scent glands responsible for sexual communication having strong attractiveness to mature males at the peak of the breeding season. The aim of this study was to evaluate, in IS in cyclic ewes, the microscopic and ultrastructure (scanning and transmission electron microscopy) anatomy, secretion composition, and mRNA and protein expression of estrogen receptors α and β and progesterone receptors. Glandular sebaceous structures occupy a superficial area of the pouch. The other glands present in the IS show a coiled tubular structure and tall and polyhedral secretory cells with irregular luminal surface resulting from the secretory process. Protein and mRNA gene transcription studies were performed to determine the presence of ER (α and β) and P4r in IS. At the follicular phase, IS cell populations analyzed using flow cytometry expressed higher levels of ERβ compared with ERα ( P  〈 0.05), whereas no difference was observed between them in the luteal phase. The IS amount of secretion was the highest in the follicular phase compared with luteal phase ( P  〈 0.05) or pregnancy ( P  〈 0.001).To the best of our knowledge, for the first time, the presence of ER (α and β) within the IS was demonstrated. As estrogen action is mediated by specific receptors in target cells, the presence of these receptors in IS might be needed to trigger signaling pathways involved in conspecific chemical (sexual) communication attributed to this area. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: ABSTRACT Light microscopy has undergone a revolution with the advent of super-resolution microscopy methods that can surpass the diffraction limit. These methods have generated much enthusiasm, in particular with regards to the new possibilities they offer for biological imaging. The recent years have seen a great advancement both in terms of new technological developments and exciting biological applications. Here, we review some of the important milestones in the field and highlight some recent biological applications. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: ABSTRACT This study focused on test the null hypothesis that there is no difference between the degree of conversion and biocompatibility of different resin reinforced glass ionomer cements (RRGICs). Forty-eight male Wistar rats were used, distributed into four groups ( n  = 12), as follows: Group C (Control, polyethylene), Group FOB (Fuji Ortho Band), Group UBL (Ultra band Lok), and Group MCG (Multicure Glass), in subcutaneous tissue. The events of edema, necrosis, granulation tissue, multinuclear giant cells, young fibroblasts, and collagen formation were analyzed at 7, 15, and 30 days. The degree of conversion was evaluated by the Fourier method. Biocompatibility and degree of conversion were assessed using the Kruskal–Wallis and Dunn tests, and ANOVA and Tukey's test, respectively ( P  〈 0.05). It was observed that, there was significant difference between Groups FOB and UBL for the presence of young fibroblasts at 15 days ( P  = 0.034) and between the Control and MCG Groups for the presence of multinucleated giant cells at 30 days ( P  = 0.009). Monomer conversion increased progressively until day 30, with significant difference between Group FOB and Groups UBL and MCG ( P  = 0.013) at 15 days. The null hypothesis was partially accepted, Fuji Ortho Band showed a less monomer conversion and a smaller number of young fibroblasts in the time of 15 days. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: ABSTRACT Several treatments have been developed aiming the prevention of bone loss. There are discussions about the best prophylactic and therapeutic procedures for osteoporosis. This study evaluated the effects of physical exercise associated with risedronate as a prophylactic and therapeutic procedure in osteopenic bones of rats submitted to ovariectomy. We used 48 Wistar rats divided into: ovariectomized or subjected to sham surgery. Ovariectomized rats were divided into the following sub-groups: OVX, 12 weeks sedentary; OVX-EX, treadmill training for 12 weeks; OVX-RA, 12 weeks with risedronate administration; and OVX-EX-RA, 12 weeks with risedronate administration and treadmill training. Rats subjected to sham surgery were divided into the following sub-groups: SH, 12 weeks sedentary; SH-EX, treadmill training for 12 weeks; SH-RA, 12 weeks with risedronate administration; and SH-EX-RA, 12 weeks with risedronate administration and training on the treadmill. The effectiveness of the treatment was evaluated in tibias using biomechanical, radiological, histomorphometric, and immunohistochemical analyses. Data were analyzed by statistical tests, with significance level of P  〈 0.05. Results of mechanical tests showed that the SH-RA group had lower values compared with OVX-RA group; densitometry showed no significant differences; according to histomorphometric methods, OVX group presented lower results than the SH-EX, OVX-RA, SH-EX-RA, and OVX-EX-RA groups, and SH-EX-RA and OVX-EX-RA groups showed values higher than SH-RA, SH, and OVX-EX groups. The SH-EX-RA and OVX-EX-RA groups had decreased immunostaining for tartrate-resistant acid phosphatase and receptor activator of nuclear factor kappa-B ligand and increased osteoprotegerin immunostaining. In this experimental model, it was concluded that the physical training associated with use of risedronate exerted positive effects on biomechanical and microstructural properties in bones of ovariectomized rats. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: The study presents an old icon painted in egg tempera on lime wood, with a poor conservation condition and clogged dirt deposits. The icon is attributed to an anonymous painter of XIXth century and to the neo-classical style of painting. The painting layer was done with only a hand full of pigments, earth colors that were often used in painting the icons from XVIIth to XIXth century in Eastern Europe, that have Byzantine influences. Taking into consideration the nature and the structure of the materials from the upper layers of the painting, affected by deposits of dirt over time, a series of cleaning recipes were studied, using the so called cleaning tests with compatible mixtures of different juices and infusion from indigenes plants, that were freshly done and odorless. A low alkaline 95% ethyl alcohol solution, combined with a few drops of ammoniac 25%, was used as a reference system, due to its compatibility with the greasy deposits found on the polychrome layer and on the wood. The cleaning capacity of the new systems used, in comparison with the standard solution, was analyzed through modern analytical methods of evaluating the degree of cleaning, more exactly by means of visible and UV reflectography, CIE L*a*b* colorimetry by reflection assisted by SEM-EDX and IR spectroscopy. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: ABSTRACT Background : There is a discrepancy between the interest in joint-reconstructions and the current knowledge about the healing-processes involved. Major reconstructions are performed with osteosynthesized allografts and fresh allografts for cartilage. Objectives : The main question to be answered is: what do we know about metaphyseal and epiphyseal cancellous bone healing, contact healing of the subchondral bone and its influence on cartilage healing? Can we achieve healing of all four compartments in contact? Purpose : The purpose is to systematically investigate through animal testing the healing processes of metaphyseal and epiphyseal bone, including the subchondral bone and the healing of cartilage of press-fit-inserted grafts, considering nondemineralized high-resolution histology. Material and Methods : Primary cancellous-bone healing of osteosynthesized hemi-osteotomies was studied in 13 canine tibial heads, the contact healing was investigated in 7 dogs and 18 giant-rabbits comparing contact-healing of press-fit-inserted autologs cylindrical grafts with empty defects applying the wet-grinding diamond-technology. Bench-experiments on the epiphyseal bones of swine including pullout-tests of cylindrical grafts formed the basis for validation of that press-fit diamond technology. Results : Primary metaphyseal and epiphyseal contact healing, including hyaline cartilage, was found in all compartments of the meta-and epiphysis in the precisely performed experiments. The press-fit principle, which employs cylindrical grafts and diamond instrumentation featuring a difference of 15/100 mm between graft and recipient bed, achieved high loads between 73.48 and 178.95 N (mean value 118.16 and standard deviation 32.79) in the pullout tests. Conclusion : Autologous press-fit grafting with alignment of the bony baseplate using wet-grinding precision has attained promising histo-morphological results. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: ABSTRACT Due to its very low hardness and atomic number, pure lithium cannot be prepared by conventional methods prior to scanning electron microscopy analysis. Here, we report on the characterization of pure lithium metallic sheets used as base electrodes in the lithium-ion battery technology using electron backscatter diffraction (EBSD) and x-ray microanalysis using energy dispersive spectroscopy (EDS) after the sheet surface was polished by broad argon ion milling (IM). No grinding and polishing were necessary to achieve the sufficiently damage free necessary for surface analysis. Based on EDS results the impurities could be characterized and EBSD revealed the microsctructure and microtexture of this material with accuracy. The beam damage and oxidation/hydration resulting from the intensive use of IM and the transfer of the sample into the microscope chamber was estimated to be 〈50 nm. Despite the fact that the IM process generates an increase of temperature at the specimen surface, it was assumed that the milling parameters were sufficient to minimize the heating effect on the surface temperature. However, a cryo-stage should be used if available during milling to guaranty a heating artefact free surface after the milling process. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: ABSTRACT Biological reactions between biomaterials and surrounding tissues, analyzed by histology, may be important predictors of clinical healing pattern and selection of slide preparation techniques requires a careful consideration regarding sample properties. In this study, we compared histology of bone specimens prepared with or without decalcification and performed histological and histomorphometrical assessments. For the histological evaluation, one-wall intrabony defects were created around the mandibular molars of six adult dogs, filled with biphasic calcium phosphate, synthetic bone graft material/recombinant human bone morphogenic protein-2, and healing pattern was histologically evaluated at 4 and 12 weeks. New bone formation in 5 × 4 × 4 mm defects and the length of new cementum, connective tissue attachments around the teeth and number of osteoclasts were measured by histomorphometric analysis. After decalcification, new cementum was easily observed and was significantly increased at week 4. In nondecalcified samples, significantly increased connective tissue attachments were seen at week 12. After 12 weeks, the number of countable multinucleated osteoclasts was significantly increased by 62% in nondecalcified versus calcified tissue sections ( P = 0.030). Histomorphometric results may be significantly affected by histological preparation method and therefore, selecting the most appropriate histological preparation method is essential for reliable diagnosis and evaluation of bony samples in studies analyzing tissue regeneration. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: ABSTRACT This article presents the experimental results of a research on six manuscripts (three of the XVIII century and three of XIX century) belonging collection of old religious books to the Moldovan Metropolitan Church of Romania. Non-invasive techniques (optical microscopy [OM], scanning electron microscopy/energy dispersive X-ray system, X-ray fluorescence analysis, shrinkage temperature, and Fourier transform infrared spectroscopy/attentuated total reflectance) provided information on the degree of degradation and identification of the leather bookbinding type. Moreover, visual assessment and OM revealed the extent of the surface degradation (wane, biological attack, change color, etc.). The degradation extent of the skin bindings was determined on the 12 samples. The insight on the mechanism of degradation was accomplished by analyzing the deterioration of collagen fibers in terms of shrinkage temperature and chemical modifications induced by oxidative and hydrolytic processes. Shrinkage temperature values were lower compared with the literature data for collagen, indicating that the leather bookbinding suffered intrinsic damage. Morphological analysis was accomplished by microscopy and allowed the identification of skin type and provided information about its processing technique. Mineral elements were identified for leather composition and contributed to the information regarding the origin and the extent of degradation of the leather bookbinding, of the studied manuscripts. The analyzed results were useful in determining the state of preservation and were able to provide an increased efficiency of further restoration. The correlation of the obtained data brought new contributions to the knowledge of the leather covers for the book technique in the XVIII and XIX centuries in monastic workshops of Eastern Europe. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: ABSTRACT Vascular remodeling in the brain occurs as a plastic change following neural over-activity. The auditory midbrain (or inferior colliculus, IC) is an ideal place to study sound-induced vascular changes because it is the brain's most vascularized structure and it is tonotopically organized. However, its micro-vascular pattern remains poorly understood. Since the IC is a sphere-like structure, the histological assessment of vasculature could depend on the angle of sectioning. Here, we studied the effects of cutting the IC at different angles on microvascular assessment, specifically: micro-vascular density and the shape of microvascular lumen. Photomicrographs were taken from 5 µm toluidine blue-stained histological sections obtained at two angles of sectioning: (a) the conventional coronal sectioning, and (b) a novel “tangential” sectioning (tangential to the dorso-medial surface of the IC). Results showed that the tangential sections, in comparison with the coronal sections, yielded (a) a higher count of micro-vascular density and (b) a higher proportion of round-shaped micro-vascular lumens. This discrepancy in results between two cut angles is likely related to the spatial pattern of blood vessels supplying the IC. We propose that the tangential sectioning should be adopted as standard for the accurate study of microvasculature in the IC. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: ABSTRACT The effect of different Ca contents on the microstructure and mechanical properties of Mg-5Al-1Bi-0.3Mn (AMB501) magnesium alloys was investigated by conventional melting and casting technique using different Ca contents (1.0, 2.0, and 3.0 wt %). Increasing the Ca content resulted in higher hardness and yield strength, but decreased elongation. The improved tensile properties of the AM50-1Bi- x Ca alloys were due to the changes in AMB501 alloy microstructure when the Ca content increased, as demonstrated by scanning electron microscope, energy dispersive spectrum, and X-ray diffractometer. The alloy microstructure indicated that the amount of β-Mg 17 Al 12 phase on grain boundaries decreased and the morphology of β-Mg 17 Al 12 phase on grain boundaries changed from quasicontinuous-net shape to dispersed particles. The Mg 17 Al 12 phase disappeared and a new secondary phase Al 2 Ca appeared after a 3.0 wt % Ca addition. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: ABSTRACT The cysts of nine Chinese populations of parthenogenetic Artemia were studied by scanning electron microscope. In the 270 cysts examined, 15 different morphological patterns were recognized with most of them not recorded in previous studies and the “tubercled shell surface” being the most common pattern. Results also displayed high intrapopulation variability, with the maximum of 11 patterns (in 30 cysts) recorded from the Barkol population. No positive correlation between the diversity of cyst shell patterns and ploidy compositions was found. Principal components analysis suggests higher similarity among coastal populations than among inland populations, which may be attributed to the identity of physicochemical conditions among coastal salterns and dissimilarity among inland saline lakes. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: ABSTRACT The results of microstructural characterization of mortars containing fly ash class C (High Calcium Fly Ash) from combustion of lignite are presented. The evaluation of the microstructure was performed using scanning electron microscope, optical, and confocal microscope. The tested beams were bent till the crack and microcracks opening, which were healed during the different curing time. The results showed that the replacement of cement with fly ash class C influenced the process of crack healing. The addition of HCFA, at both 30% and 60%, speeds up the self-healing process in cracks and particularly in micro-cracks. In the research, the completely filling up of the cracks by new phases has not been observed, only the beginning of such process has been noticed. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: ABSTRACT We propose two-photon excitation-based light-sheet technique for nano-lithography. The system consists of 2 -configured cylindrical lens system with a common geometrical focus. Upon superposition, the phase-matched counter-propagating light-sheets result in the generation of identical and equi spaced nano-bump pattern. Study shows a feature size of as small as few tens of nanometers with a inter-bump distance of few hundred nanometers. This technique overcomes some of the limitations of existing nano-lithography techniques, thereby, may pave the way for mass-production of nano-structures. Potential applications can also be found in optical microscopy, plasmonics, and nano-electronics. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: ABSTRACT This study evaluated the bond strength (BS) and the adhesive interface of four endodontic sealers to root canal dentine, before, and after immersion in phosphate buffered saline (PBS) to simulate an in vivo environment. Eighty roots were instrumented using ProTaper rotatory files, under irrigation with 17% EDTA and 1% NaOCl. Posteriorly were divided into four groups ( n = 20) according to the sealer used: Endofill, AH Plus, Sealapex, and MTA Fillapex. Each group was divided into two subgroups ( n = 10) and stored at 37°C immersed in water for 7 days and in PBS for 60 days. From each subgroup, 1 mm thick sections were obtained. One section of each region (coronal, middle, and apical) was submitted to the push-out test and failures were observed. Twelve sections of each subgroup (four from each region) were evaluated under SEM. Three-way ANOVA evaluation for BS showed significant differences between groups and regions ( P 〈 0.0001), but not between subgroups ( P 〉 0.05). AH Plus had significantly higher BS than the others sealers, regardless of the analyzed subgroup (Tukey's test, P 〈 0.5). The most common failures were adhesive to dentine and cohesive of the sealer. The SEM evaluation (Kruskal–Wallis, Mann–Whitney) showed homogeneous adhesive interface formed and sealer tags in all groups with significant statistical differences with AH Plus, regardless of PBS immersion. AH Plus was superior to the other sealers for both BS and quality of interface formation. Immersion in PBS did not interfere on BS or adhesive interface of the sealers tested. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: ABSTRACT Purpose This study used five clinical assessments and Raman spectroscopy to investigate the age- and hyperglycemia-related properties of the murine retina over an eight-week experimental period. Method Acute hyperglycemia and chronic hyperglycemia were assessed with blood glucose (BG) and glycated hemoglobin (HbA1c) levels, respectively. Changes in the retinal thickness and neovascularization were evaluated with optical coherence tomography and fluorescein angiography (FAG). Histological changes in the retina were studied after periodic acid-Schiff (PAS) staining. Raman spectroscopy was used to examine the molecular structures and chemical compositions of the retinal tissues. Results The young hyperglycemic group had acute hyperglycemia with a BG level of 576 ± 22 mg/dL and HbA1c of 5.9 ± 0.6%, while the aged hyperglycemic group displayed chronic hyperglycemia with a BG level of 607 ± 28 mg/dL and HbA1c of 11.2 ± 1.5%. Aged hyperglycemic retinas showed an insignificant (5%) decrease in thickness and no presence of vascular leaky lesions with FAG. There was no histological evidence of the retinal neovascularization with PAS staining of these aged hyperglycemic retinas. In the aged group, Raman intensities assigned to the C–C symmetric breathing of the aromatic ring in phenylalanine (1003 cm −1 ), the NH 2 amide III α-helix deformation in the protein structure (1265 cm −1 ), and the C=O stretching vibration of amide I α-helix structure in collagen (1657 cm −1 ) were all decreased. Conclusion These decreased Raman intensities indicate elevated reactive oxygen species (ROS) and oxidative damage to proteins such as those involved in cell apoptosis. A decrease in these ROS-related Raman peaks indicates an aging effect on the retina. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: ABSTRACT This study analyzed the quality of obturation and physical properties of MTA Fillapex and AH Plus sealer. A sample of 30 human maxillary central incisors were instrumented with Protaper until a F5 (50/05) file. Both sealers were mixed with Rhodamine-B dye to allow visualization on a confocal laser-scanning microscope (CLSM). Next, the canals were filled using the single cone technique. After setting, all samples were sectioned at 2, 4, and 6 mm from the apex. CLSM was used to analyze the gaps and sealer penetration into the dentinal tubules. All samples were scanned 10 µm below the dentin surface and images were recorded at 100× magnification using the fluorescent mode. Additionally, the solubility, flowability and setting time of the sealers were evaluated. All the measured quantities of the examined materials were evaluated for significant differences by means of statistical analysis. The CLSM analysis of the MTA Fillapex showed the highest percentage of gaps at all sections (P = 0.0001). Physical tests revealed adequate properties for both sealers except for a higher solubility of the MTA Fillapex (P = 0.0001). The MTA Fillapex presented flowability and intratubular penetration similar to the AH Plus. Nevertheless, the MTA Fillapex sealer presented a higher solubility and considerable quantity of gaps between the sealer/dentin interface in relation to the AH Plus sealer. Clinicians must take into consideration, the quality of endodontic sealers as it is essential in the outcome of the root canal filling. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: ABSTRACT Macro and microdissection methods, conventional histology and immunohistochemical procedures were used to investigate the nasal cavity and turbinate complex in fetal and adult sheep, with special attention to the ethmoturbinates, the vestibular mucosa, and the septal mucosa posterior to the vomeronasal organ. The ectoturbinates, which are variable in number and size, emerge and develop later than the endoturbinates. The olfactory sensory epithelium is composed of basal cells, neurons, and sustentacular cells organized in strata, but numerous different types are distinguishable on the basis of their thickness and other properties; all variants are present on the more developed turbinates, endoturbinates II and III. Mature neurons and olfactory nerve bundles express olfactory marker protein. We found no structure with the characteristics that in mouse define the septal organ or the ganglion of Grüneberg. Our results thus suggest that in sheep olfactory sensory neurons are exclusively concentrated in the main olfactory epithelium and (to a lesser extent) in the vomeronasal organ. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: ABSTRACT With the application of the elements of all major super-resolution techniques including stimulated emission depletion, structure illumination microscopy, and photo-activated localization microscopy, the incoherent crossed standing-wave microscopy achieves parallel super-resolution imaging. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: ABSTRACT The Sarcophagidae are one of the most numerous groups of Diptera in the world, consisting of many species of forensic interest, whose immature stages are useful in the estimation of postmortem interval. The immature stages of some species of forensic importance still remain unknown or undescribed, like in the case of Sarcophaga ( Liopygia ) cultellata Pandellé, 1986, a species restricted to the Iberian Peninsula, south of France and north of Italy, which shares a ecological niche with species of the same subgenus, e.g., Sarcophaga ( Liopygia ) argyrostoma (Robineau-Desvoidy, 1830) and Sarcophaga ( Liopygia ) crassipalpis Macquart, 1839, making it necessary to lay the groundwork for a proper specific differentiation before it can be successfully applied in forensic practice. This study provides the first micromorphological description of all preimaginal stages of S . ( L .) cultellata using light microscopy and scanning electron microscopy (SEM), the results of which allow the morphology of the main features to be followed during the immature life cycle. We propose a combination of features for distinguishing Liopygia from other sarcophagid subgenera, based on the current level of morphological knowledge of immature stages. S . ( L .) cultellata can be differentiated from S . ( L .) argyrostoma and S . ( L .) crassipalpis in every immature stage by both light microscopy and SEM. The presence of tegumental warts and a fan-shaped anterior spiracle with a single row of 15–18 respiratory papillae allow distinguishing the third instar larvae of S . ( L .) cultellata from other Sarcophaga species described hitherto by SEM. Identification keys based on light microscopy observations are provided, covering all the immature stages of Liopygia subgenus occurring in the Iberian Peninsula. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: ABSTRACT The Caribbean bivalves Codakia orbicularis (Linné, 1758) and C. orbiculata (Montagu, 1808) live in seagrass beds of Thalassia testudinum and harbor intracellular sulfur-oxidizing gamma-proteobacteria. These bacterial symbionts fix CO 2 via the Calvin Benson cycle and provide organic compounds to the bivalve. During experimentally induced starvation, no reduced sulfur compounds and no organic particle food are available; the symbionts could be considered as the sole nutrient source of the host bivalve. A previous study has shown that the intracellular bacterial population decreased considerably during starvation and that bacterial endosymbionts were not released by the bivalves. In this study, the activity of two lysosomal marker enzymes (acid phosphatase and arylsulfatase) was detected using cytochemical experiments coupled with energy-dispersive X-ray transmission electron microscopy during sulfide and organic particle starvation. The degradation of bacterial endosymbionts began after 2 weeks of starvation in C. orbiculata and after 3 weeks in C. orbicularis . Degradation processes seem to be continuous over several months and could be responsible for the disappearance of the bacterial endosymbionts within the gills during starvation. These data suggest that the host use symbionts as a nutrient source to survive a hunger crisis. The carbon transfer from the symbionts to the host could be flexible and could consist in transfer of organic matter, “milking,” under normal feeding conditions and digestion of the symbionts under starved conditions. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: ABSTRACT In this study, we aimed to describe the morphological characteristics of the lingual papillae in two species of Otariidae family by stereomicroscopy and scanning electron microscopy. We used tongues of two South American Otariidae species. The tongues were elongated and terminated in bifid apex and there was no median sulcus on the dorsal lingual surface. The most numerous type of lingual papilla was filiform in the South American fur seal (SASL) and entire dorsal lingual surface was covered by these filiform papillae but the dorsal surface of the tongue of the South American sea lion was covered by numerous polygonal projections, which were different in size. Fungiform papillae were detected in only SASL and they randomly distributed on the lingual apex and body, and some fungiform papillae were collected into twosome or threesome groups on the posterior part of the lingual body. Circumvallate papilla was found in the center of the lingual radix of South American sea lion. Thread-like conical papillae were common for both species and they located on the lingual radix. We determined that lingual surface morphology was completely different in each species, although they were members of the same family, Otariidae. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: ABSTRACT Accurately accessing changes in the intracellular volumes (or numbers) of peroxisomes within a cell can be a lengthy task, because unbiased estimations can be made only by studies conducted under transmission electron microscopy. Yet, such information is often required, namely for correlations with functional data. The optimization and applicability of a fast and new technical proceeding based on catalase immunofluorescence was implemented herein by using primary hepatocytes from brown trout ( Salmo trutta f. fario ), exposed during 96 h to two distinct treatments (0.1% ethanol and 50 µM of 17α-ethynylestradiol). The time and cost efficiency, together with the results obtained by stereological analyses, specifically directed to the volume densities of peroxisomes, and additionally of the nucleus in relation to the hepatocyte, were compared with the well-established 3,3'-diaminobenzidine cytochemistry for electron microscopy. With the immuno technique it was possible to correctly distinguish punctate peroxisomal profiles, allowing the selection of the marked organelles for quantification. By both methodologies, a significant reduction in the volume density of the peroxisome within the hepatocyte was obtained after an estrogenic input. The most interesting point here was that the volume density ratios were quite correlated between both techniques. Overall, the immunofluorescence protocol for catalase was evidently faster, cheaper and provided reliable quantitative data that discriminated in the same way the compared groups. After this validation study, we recommend the use of catalase immunofluorescence as the first option for rapid screening of changes of the amount of hepatocytic peroxisomes, using their volume density as an indicator. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: ABSTRACT Decalcification of mineralized tissues is an essential step during tissue processing in the routine histopathology. The time required for complete decalcification, and the effect of decalcifier on cellular and tissue morphology are important parameters which influence the selection of decalcifying agents. In this study, we compared a decalcifying solution (ETDA) composed of both acid and chelating agents to a classical and well-known decalcifying agent (EDTA). To this purpose, the optic density of bone radiographs, residual calcium analysis, bone sample weight, and histological and immunohistochemical analysis were performed. Our data suggest that, similarly to EDTA, the ETDA solution completely removes the calcium ions from the samples enabling easy sectioning. However, unlike the EDTA, this agent takes much less time. Furthermore, both agents showed comparable decalcification efficacy, and similarly, they did not produce cellular, tissue or antigenicity impairments. Therefore, ETDA may be a suitable option when it is necessary an association between a rapid and complete removal of calcium minerals, and a suitable preservation of structure and antigenicity of tissues. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: ABSTRACT The organization of the egg capsule of the euholognathan stonefly, which represents the family Taeniopterygidae (Nemuroidea) was investigated using light and electron microscopy techniques. The presence of a complex, multilayered egg capsule, composed of a vitelline envelope, multilayered chorion, and extrachorion is described. The morphology of the eggshell of Brachyptera risi was compared with that of euholognthan and systellognathan egg coverings and the ground plan of the egg capsule in Plecoptera was discussed. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: We study the zero dynamics and funnel control for linear passive electrical circuits. We show that asymptotic stability of the zero dynamics can be characterized by criteria on the circuit topology. Thereafter we consider the output regulation problem for electrical circuits by funnel control. We show that for circuits with asymptotically stable zero dynamics, the funnel controller achieves tracking of a class of reference signals within a pre-specified funnel. This result can be relaxed to the case of non-autonomous zero dynamics by requiring the reference trajectory to evolve within a certain subspace. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

Description: This paper presents a new approach for analysis and controller design for nonlinear descriptor systems. Thereby, we assume that the descriptor system is given in semi-explicit form and has a continuously differentiable solution, which are very mild assumptions and are fulfilled for most practical applications. Based on the known coupling controller design we transfer the analysis and synthesis from the descriptor system to an equivalent system in state-space form. Methods like dynamic and static input-output decoupling, input-output linearization, model-based feedforward-controller design, zero dynamics, exact descriptor linearization, linear time variant Riccati control, and causal observer design have been introduced based on the coupling procedure [9]. In the following, we summarize the new approach and an algorithm to compute the required state-space system. Additionally, a short introduction how to use it for decoupling control, Riccati control, and causal observer design is given. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

Description: Linear dynamical systems with an affine parameter dependence producing low-rank variation in the state matrix can be recast as a nonparameterized system operating in parallel with a parameterized feed forward term operating under output constraints. This mapping permits the application of standard (nonparametric) model reduction strategies to solve parameterized problems. We demonstrate the approach on a parameterized vibration problem using optimal tangential interpolation. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

Description: Different variants of the eXtended Finite Element Method (XFEM) have developed over the last years: The original, shifted, corrected, stable, and intrinsic XFEM. Herein, these variants are compared in terms of convergence rates and conditioning of the resulting systems of equations. Optimal convergence rates are achieved by the corrected, stable, and intrinsic XFEM for general enrichments. The original and shifted XFEM achieve optimal rates for selected enrichments only. In terms of the conditioning, it is found that the stable XFEM can be “optimal” in the sense that the same dependency on the mesh size as for the classical FEM is maintained. However, this finding only holds if one enrichment term is involved. In the presence of several enrichment terms, only the intrinsic XFEM yields well-conditioned systems of equations. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

Description: We study controllability of switched DAEs and formulate a definition of controllability in the behavioral sense. In order to characterize controllability for switched DAEs we first present new characterizations of controllability of non-switched DAEs based on the Wong-sequences. Afterwards a first result concerning the single-switch case is presented. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

Description: In 2009, the BEM-based FEM was introduced as an numerical approach for the treatment of boundary value problems. It is a Finite Element Method (FEM) that uses Trefftz-like basis functions which are defined to fulfil the underlying differential equation locally and which are treated by means of Boundary Element Methods (BEM). Due to the implicit definition of basis functions, this approach is applicable on general polygonal and polyhedral meshes and yields conforming approximations. The elements of the discretization do not necessarily have to be convex. After a review of the recent development of higher order basis functions the method is applied to a model problem on a sequence of meshes with L-shaped elements. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

Description: Designing whole machines or processes you may need both, an integrated dynamic simulation of all components on system level and a detailed analysis of how the macroscopic behavior of a component depends on geometry and material parameters. The former analysis is usually based on systems of differential algebraic equations representing a component by not more than a few hundred states and requires tools like Matlab-Simulink® or Dymola®. The latter analysis solves discretized partial differential equations with several 100,000 degrees of freedom using finite element software like Ansys® or Comsol®. Model reduction bridges the gap between the two worlds providing small state space models with approximately the same input-output behavior as the original large finite element models. Building systems from generic components, e.g. a gas transport network from pipeline models with variable length, or optimizing the design of a device with respect to mechanical or thermal properties, we need parametric reduced models. The idea is to reduce FE models offline for selected parameter sets and to generate models for new parameters by cheap interpolation rather than expensive reduction. The different approaches to parametric linear model reduction may be divided into three classes [1]. Interpolation of transfer functions is well suited for parabolic or highly damped hyperbolic problems. However, poles are duplicated rather than shifted, which is unacceptable for weakly damped hyperbolic problems like in mechanics. The second class of methods look for a basis of state space covering system behavior over the full range of parameters. They share the critical assumption that number and meaning of states do not change with the parameters. In terms of finite elements this means that the meshes for different design parameters are morphed variants of the same reference mesh.This may become a severe restriction in practice when automatic meshing is to be applied to complicated geometries. Therefore, we propose a method from the third class, which is based on interpolating reduced system matrices [2]. Only those parts of the mesh need to share a constant topology where nodal inputs are applied and outputs are collected. The inner mesh, however, may change for different parameters. The main challenges arise from the fact that state space representations of a system are unique only up to a change of basis and that interpolating matrices which refer to non-fitting bases may cause arbitrary errors. In the article we will show how problems like leaving and entering modes or eigenvalue crossing can be overcome by using normal forms and eigenvalue tracking in parameter space. The method, which is implemented in the Fraunhofer Model Reduction Toolbox, is applied to a parametric model of a mechanical device the eigenfrequencies of which have to be kept away from some dominant excitation frequencies. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

Description: In the view of robotics or granular media mechanics, we ask for the statement of the dynamical evolution problem for multibody systems with contacts and friction. The “event driven” approach does not allow to state an evolution problem in a systematic way: it gives a peculiar status to the instants of impact and to the contact points although they are unknowns of the problem. This matter of fact has given rise to a new approach in the frictionless case [4, 6] we generalize to the case including friction. Following to the point of view of Lagrange on the equation of the dynamics, we emphasize the systematic use of virtual powers and duality. This bias suggests to put emphasis on generalized reaction forces in the statement of the evolution problem and not on local reaction forces of the real world. This point of view allows to escape from pathologies e.g. Painlevé paradox [5] and Kane Paradox [3]. The proposed evolution problem accounts for impacts and friction in case of multiple unilateral constraints. We prove the existence and uniqueness of the solution to the associated rate problem. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

Description: Ancorsteel1000C is commonly used for important components including bearing rollers, gears, connecting rods, wheels and rails; most failures of these components are caused by rolling contact fatigue (RCF). In this study the fatigue damage indicator based on Fatemi-Socie critical plane were determined in a local hot spot area in finite element (FE) model in case of Hertzian stress with zero slip condition. The simulation results compared with respect to experimental data, which is in good agreement. Therefore, this approach can be implemented as a useful tool for lifetime calculations in RCF in the process of structure fatigue design. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

Description: This paper presents selected results of experimental tests carried out on the three-storey plate-column structure, which is a physical model of a building. On the top floor the semi-active tuned mass damper (STMD) is installed. That device is a kind of harmonic oscillator with a variable stiffness characteristic. The tuning of STMD is possible in the frequency range from 0 to 5 Hz, which allows to counteract the resonant vibration of plate-column structure for the three basic frequencies. The model's vibration are kinematically excited by using the earthquake simulator. It is assumed that during an experimental tests the plate-column structure's vibration are only excited by horizontal component of base motion (dominant influence on building's vibration). The aim of the experimental analysis presented in this paper is to verify the effectiveness of the semi-active tuned mass damper in vibration's amplitude reduction of the main structure. The tested device is prototype of STMD, which uses a competitive constructional solution of stiffness parameter control. By reason of above, special attention is focused on the testing of vibration eliminator in two aspects: change of stiffness characteristic (the rate of change), and the accuracy of tuning to the resonant frequencies. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

Description: In structural dynamics the initial boundary value problem has to be solved in the space and time domain. The spatial discretization is done using finite elements. For the temporal discretization two classes of Runge-Kutta methods and the generalized-α method are compared. The representatives for the Runge-Kutta methods are diagonally implicit Runge-Kutta schemes (DIRK) and diagonally implicit Runge-Kutta-Nyström schemes (DIRKN). (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

Description: This paper deals with a GALERKIN-based multi-scale time integration of a viscoelastic rope model. Using HAMILTON's dynamical formulation, NEWTON's equation of motion as a second-order partial differential equation is transformed into two coupled first order partial differential equations in time. The considered finite viscoelastic deformations are described by means of a deformation-like internal variable determined by a first order ordinary differential equation in time. The corresponding multi-scale time-integration is based on a PETROV-GALERKIN approximation of all time evolution equations, leading to a new family of time stepping schemes with different accuracy orders in the state variables. The resulting nonlinear algebraic time evolution equations are solved by a multi-level NEWTON-RAPHSON method. Realizing this transient numerical simulation, we also demonstrates a parallelized solution of the viscous evolution equation in CUDA©. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

Description: In this paper, the kinematic performance of flexure hinges and compliant mechanisms calculated by conventional modeling techniques are compared. As these exhibit certain drawbacks with regard to control strategies, mainly large number of degrees of freedom or unacceptable errors, a novel modeling approach for flexure hinges is presented. Instead of the entire flexure hinge only its significant regions are modeled by 3-D structural solids. These master patterns are positioned appropriately and connected by rigid constraint conditions to build a compliant mechanism. The resulting model is characterized by considerably fewer degrees of freedom than a full solid model as well as a marginal deviation of the deflection compared to that of pseudo-rigid-body models, 3-D tapered finite beam elements and analytical Timoshenko beam theory. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

Description: This paper presents a time integrator, which is based on a time discrete spatially weak finite element formulation, but fulfills the same balance laws as the underlying (five) differential equations. Namely, in addition to the balances of linear and angular momentum as well as entropy, also the balances of total energy and LYAPUNOV function are fulfilled. The spatially weak formulation is obtained by integration by parts. Where the resulting virtual stress power term is well-known, the virtual entropy production by conduction of heat is less known. The time discretisation is based on the midpoint rule and non-standard time discrete differential operators. This time integrator is a further development of the TC integrator of I. ROMERO. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

Description: At the Helmholtz-Zentrum Dresden-Rossendorf an experimental plant is developed to investigate the formation of magnetic fields in flows of liquid metals. Because of the enormous hazard potential of the used liquid sodium it is essential to avoid any damages during operation and so a detailed analysis using the finite element method is necessary considering the various mechanical and thermal loads. Therefore several tens of thousands load cases have to be taken into account. Hence an algorithm is developed to identify the relevant stresses referring to FKM guideline which are used for the static and fatigue strength assessment. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

Description: This contribution deals with the modelling and simulation of curing phenomena in adhesively bonded piezo metal composites which consists of a piezoelectric module enclosed by an adhesive layer which in turn is surrounded by two metal sheets. A short survey on the neccessary experimental investigations to characterise the adhesive's material behaviour is given and important aspects on the corresponding phenomenological modelling approach are presented. Both steps take into account the curing reaction, changes of volume, like chemical shrinkage, and inelastic mechanical behaviour which is temperature and curing dependent. Finally, the simulation strategy for the modelling within a finite element environment is depicted. By this, residual stresses, secondary deformations and loads on the piezo modules can be predicted, which is exemplified by a comparative study verifying a novel manufacturing strategy. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

Description: Increasing requirements on the durability of road pavements demand the conception of innovative asphalt types. Particularly the stability under load needs improvement in order to prevent rutting. Since the load bearing capabilities of asphalt are mainly governed by the granular lattice and the binder that glues the rocks together, simulation based approaches that aim on supporting R&D in road engineering must capture the granulometry of the material. A Voronoi tesselation based description of the structure is proposed that enables the separate modelling of grains and binder as continuous materials and attempts to accurately reproduce those features. First, a neat Voronoi tesselation is created within the modelling domain. These irregular convex polyhedra representing the grains are subsequently subject to a shrinking process and further modified to accurately represent the granulometric distribution of real asphalt types. Now, the space between the grains can be used for a volumetric representation of the binder. Full-field strain measurements during the indirect tensile test of mastic asphalt, stone mastic asphalt and asphalt concrete have been performed for validation of the approach. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

Description: The following contribution focuses on the FEM-simulation of “Die-Less-Hydroforming” using LS-DYNA. That specific forming technology is used to create structures by inflating initial seal-welded flat 2D blanks as well as 3D hollow bodies without using any die, mould or punch in contrast to conventional hydroforming (e.g. tube hydroforming or hydromechanical deep drawing). (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

Description: We discuss the infinite time-horizon linear-quadratic optimal control problem for differential-algebraic equations. In contrast to previous approaches we do not impose any assumptions on the system except for impulse controllability. In particular, we show that the optimal control problem is feasible if and only if a dissipation inequality has a solution. Moreover, we discuss conditions under which the problem has a minimizing (instead of only an infimizing) solution and furthermore, when this minimizing solution is unique. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

Description: Topology optimization techniques are applied in most cases for static applications. However, recently topology optimization procedures for structures under dynamic loads have been the focus of several studies. In this work, a topology optimization scheme for flexible multibody systems using equivalent static loads and displacement fields is investigated. The optimization problem is formulated using a homogenization method, more precisely, the solid isotropic material with penalization (SIMP) approach. The objective function in the optimization problem is the compliance and the method of moving asymptotes is used as optimizer. The objective function and the sensitivities are computed directly from the displacement field computed in the dynamic simulation. The examples of a 2-arm manipulator and a slider-crank mechanism are presented and the results are discussed to verify the improved dynamical behavior through this optimization method. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

Description: For the dynamic response of multilayer sheet structures it is important to take nonlinear contact and friction forces between the layers into account. The nonlinearities inside the joints can significantly influence the dynamic behavior of the entire structure. For the dynamic analysis of such structures conventional computational approaches have an unbalanced ratio between computational time and accuracy. In order to overcome this problem, so-called “Joint Interface Modes” (JIMs) are used. These JIMs, which are problem-oriented trial vectors, extend the reduction base of classical trial vector based reduction methods. In this contribution a new calculation approach for JIMs based on trial vector derivatives is introduced. The result quality of the presented method is comparable to the direct finite element method but the computational effort is extremely low due to model order reduction. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

Description: This paper discusses the refinement of multibody models by integration of flexible bodies and by considering nonlinearities from contacts. It presents common approaches for contact modeling in multibody simulations and strategies to include flexible bodies. A contact model is implemented in the elastic multibody model. Experimental results show that significant effects of system dynamics can be modeled by use of a multibody model including elastic bodies and contacts. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

Description: In this work, the nutation momentum acting upon the Earth from the Moon's perigee mass that has not been taken into account in the Earth's precession-nutation theory was revealed. This missing momentum exhibits itself in the so-called “local latitude variation” with the Chandler's period. The results of our work raise the question of updating the Earth's precession-nutation theory and revising some postulates of the time service, astronomy, geophysics, satellite navigation, etc. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

Description: In underactuated dynamical systems, the number of control inputs n u is smaller than the number of degrees of freedom n q . Real world examples include e. g. flexible robot arms or cranes. In these two exmples the goal is to prescribe the trajectory of an end effector and find the necessary control variables. One approach to model these problems is to introduce servo constraints in the equations of motion that enforce a given trajectory for some part of the system [1]. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

Description: In the context of multibody simulation (MBS) system parameter identification within acceptable time can be challenging. One main difficulty is the huge amount of degrees of freedom in multibody systems and therefore the large number of dependent variables. The present work deals with the evaluation of different approaches that can be applied to typical parameter identification problems in MBS. A very powerful possibility is given by the adjoint sensitivity analysis that allows to reduce the computation effort dramatically. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

Description: The investigated multibody dynamics involve perfectly elastic, partially elastic and perfectly plastic contacts and a structure preserving approach is used in forward dynamics and optimal control simulations. The applied mechanical integrator is based on a constrained version of the Lagrange-d’Alembert principle and it represents exactly the behaviour of the analytical solution concerning the consistency of momentum maps and symplecticity: it is called symplectic momentum scheme. To guarantee the geometric exactness during the establishing or releasing of contacts, the non-smooth problem is solved including the computation of the contact configuration, time and force, instead of relying on a smooth approximation of the contact problem via a penalty potential. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

Description: The usage of flexible bodies in Multibody simulations (MBS) has widely increased their industrial application. Finite Element (FE) models with up to 10 million degrees of freedom (DOF) and some hundred million nonzero matrix entries are used to describe the flexible bodies. Before such a model can be included into an MBS, the number of DOF must be reduced to an appropriate size. Using modal reduction often the critical issue arises which modes to choose while Component Mode Synthesis based methods often lead to a relatively big size of the resulting model. Alternative methods using Moment Matching and Balanced Truncation can result in a smaller size while still remaining accurate enough. Sometimes these matrices are so huge that they can not even be stored in one computers main memory. The calculation of the necessary orthogonal Krylov subspaces needs an LU factorization which is also very memory intensive. To meet these requirements, distributed computation is used which also shortens the computational time of the reduced process. In this work, an industrial relevant FE model is reduced to a much smaller size using alternative methods. Accuracy is verified by comparing the frequency response in a defined frequency range of the original and the reduced model. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

Description: For many robotic applications with tasks such as cutting, assembly or polishing, it is necessary to get in contact with the surrounding. In this paper a redundant robot with seven degrees of freedom in a metal polishing task is considered. For simulation as well as for the controller design a dynamic model of the robot and a contact model are required. The equations of motion of the robot are calculated with the Projection Equation in subsystem representation and the contact model contains linear tool elasticities and work piece elasticities. In the case of a polishing task, a constant contact force during the process is required even if the robot moves along a trajectory. Thus some degrees of freedom of the robot tool center point have to be position controlled while the other ones have to be force controlled. The redundant robot offers the possibility to avoid singular positions or to maximize the available end-effector forces within the inverse kinematics and is therefore best suited for polishing large objects. The actual process forces are measured with a six axis force-torque-sensor mounted at the tool center point. These forces are used in a parallel force/position control law to achieve the desired behavior. Results from measurements of a test arrangement are presented. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

Description: The use of robotic manipulators in remote and sensitive areas calls for more robust solutions when handling joint failure, and the industry demands mathematically robust approaches to handle even the worst case scenarios. Thus, a systematic analysis of the effects of external forces on manipulators with passive joints is presented. In parallel manipulators passive joints can appear as a design choice or as a result of torque failure. In both cases a good understanding of the effects that passive joints have on the mobility and motion of the parallel manipulator is crucial. We first look at the effect that passive joints have on the mobility of the mechanism. Then, if the mobility, considering passive joints only, is not zero we find a condition for which the parallel manipulator is conditionally equilibrated with respect to a specific external force. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

Description: In this article the authors outline how systematic multi-body equations can efficiently be used to derive a model for the design of a nonlinear vehicle dynamics controller for truck-semitrailer combinations, steering the last trailer axle. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

Description: An automotive suspension system represents one of the most complex and important systems in a passenger vehicle, which has to ensure a robust and optimized contact between the wheels and the road at any time. For improving a suspension system it is important to take an investigative look at the interaction between suspension, tire and road dynamics. Thus a part of a study into aspects of suspension modeling on multi-body simulations of rear multi-link suspension system dynamics with focus on the tire footprint area is presented in this work. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

Description: For systems that contain slow and fast dynamics, variational multirate integration schemes are used. These schemes split the system into parts which are simulated using a time grid consisting of micro and macro nodes. This leads to computing time savings, however not unlimited, for a certain number of micro steps per macro step the computing time is minimal. To find a relation between this minimum computing time and the number of variables in the system, the computing time for the Fermi-Pasta-Ulam problem (FPU) is measured for different numbers of masses and different numbers of micro steps. In addition, the numerical convergence of the variational multirate integration is shown for the FPU. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

Description: In the present paper, a new formalism for obtaining the kinematical equations of a rigid body motion is proposed. It is based on an alternative parameterization of the Lie group SO(3). Here we provide a new description of attitude kinematics by means of decomposing an arbitrary rotation into a pair of successive rotations about a fixed axis û and a varying one v̂ , which is perpendicular to û . Then û , v̂ and û × v̂ constitute a basis, in which it is most natural to obtain the kinematic equations. The latter appear to be quite simple when they are expressed in terms of the vector-parameter provided that the rotation about the fixed axis is applied first (in the body reference frame). The procedure is illustrated in different situations, in which explicit solutions are available. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

Description: The phenomenon of self-locking can be found in many technical applications and common machine parts, such as screws, chocks, and funnels. Despite this, research into this topic is mostly limited to specific applications (e.g., worm gears, screws, kinematic chains). Current works with a general scope are rare. This paper addresses the analysis of self-locking in different, two-dimensional, multibody systems, and shall contribute towards a more general analysis. To elaborate on the characteristics of self-locking, the effect is first shown and explained using simple systems as examples. From these examples, an approach towards a generalized description of self-locking is proposed, which is used as a foundation for the development of two identification methods. The analysis of the self-locking mechanism in multibody systems is realized first through an analytical ansatz, and then using a numerical simulation of the examples shown. The analytical and numerical analyses of the systems deliver a criterion, and respectively an algorithm, which enables the identification of self-locked assemblies in different systems of multiple bodies. The algorithm is designed to identify self-locking during integration of the equations of motion, whereas the analytic criterion is formulated for static systems with known, increasing external loads. The results of the two analysis methods correspond very well for the given example systems, leading to the conclusion that both methods are equivalent and usable. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

Description: Growth in living materials is the result of the changes in volume and mass during their development. If volume expansion occurs in a constrained case, some living materials change its growth behaviour. For example, when growth takes place in an environment with restrictions of volume, living materials will stop their volume expansion under compression due to the high amount of water that makes these bodies nearly incompressible. In case boundary conditions limit the growth of the body, the growth direction changes and gives the body another shape as expected. We present a modelling approach that takes volume and shape restrictions during growth into account. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

Description: The development of the human brain with its characteristically folded surface morphology remains an intensively discussed topic. Impressive advancements in different fields of research have enhanced the understanding of the brain. However, the mechanism that underlies the folding process in healthy and diseased brains remains undetermined. Here, we hypothesize that growth induced mechanical instabilities drive folding. Using the nonlinear field theories of continuum mechanics supplemented by the theory of finite growth [1], we model the human brain as a bi-material with the cerebral cortex, a morphogenetically growing outer layer of gray matter, and the subcortex, a strain-driven growing inner core of white matter [2]. This approach integrates the two popular but competing hypotheses that cortical folding is either driven by differential growth or by axon elongation. Through systematic sensitivity analyses, we identify the critical process parameters of cortical folding and quantify their impact on brain morphology. We further simulate phenomena causing malformations like lissencephaly and polymicrogyria [3], which are associated with neurological disorders, including severe retardation, epilepsy, schizophrenia, and autism. Understanding the mechanisms of cortical folding during brain development might facilitate the diagnostics and treatment of malformed brains. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

Description: This contribution deals with the modeling of the physiological behavior of arterial walls, in order to enable a reliable calculation of the transmural stress distribution including also the active response of arterial tissue. Therefore, a simple viscoelastic model, which only requires few material parameters, is considered. Furthermore, a comparative study, investigating the influence of viscoelasticity on the mechanical behavior of arterial walls, is presented. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

Description: This study focuses on a formulation within the theory of porous media (TPM) for continuum multicomponent modeling of osmotic driven deformation in articular cartilage. The cartilage consists of porous solid matrix (extracellular matrix(ECM)),which is reinforced by collagen fibers and saturated by a fluid phase. The solid and fluid phases are considered as immiscible constituents occupying spatially their individual volume fraction. However, both phases include electrolytes, which are responsible for the osmotic pressure. The collagen fiber induce both, a transverse-isotropic stress and permeability behavior which is represented in the modal approach by an invariant-based description for the stress and anisotropic permeability tensor for the fluid flow, respectively. The osmotic pressure is captured by considering the electro-chemical potential of the electrolytes. After discussing the main details of the large-strain coupled poro-osmotic-hyper-elastic model approach, a brief numerical example is given. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

Description: Long-term studies reveal that mechanical stimulation causes growth and remodeling phenomena within biological tissues. The main aim of this research is to fully understand and control these phenomena. For accomplishing that, two steps are considered: first, we determine a suitable numerical model based on different approaches by a comparative study using experimental validations, and second, investigate the mechanical properties of the tissue specimens after a remodeling process. We start with the first step by choosing a convenient model that mimics the biotissue for running the numerical simulations in the second step. There are different models available that determine the mechanical properties of soft replacement tissues seeded with human chondrocytes in modern medical applications. It is our objective to achieve a common methodology of theory and experiments that allows the determination of the mechanical properties of the native material. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

Description: The stability of the human spine is highly dependent on the cancellous bone structure of the vertebra. In the case of osteoporosis and accompanied weaking of the vertebral structure, compression fractures and other lesions of the affected patient may occur. The reinforcement of the porous cancellous bone by the injection of bone-cement is a common procedure in order to overcome this issues. The modelling and computational simulation of vertebroplasty, i.e., bone-cement-injection into the vertebra, is of major interest to obtain valid and reliable predicitions for this surgery. A detailed micromechanical (and locally single-phasic) model exhibits the drawback that all geometrical and physical transition conditions of the individual parts and their complex microstructure have to be known. Therefore, this study considers a macro-scopic (and multi-constituent) continuum-mechanical model based on the Theory of Porous Media, where the homogenisation of the underlying micro-structure results in a model of three constituents. In particular, these are the solid bone skeleton, which is saturated by bone marrow, where the latter may be displaced by the injected liquid bone cement. The micro-architecture is regarded by heterogeneous and anisotropic permeability tensors and the preferred directions of the trabecular bone structure. The presented strongly coupled macroscopic model offers the opportunity to not only simulate the flow of the pore fluids but also predicts the arising stresses and strains of the solid bone skeleton due to the numerical investigation of the injection process. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

Description: Taking into account softening effects in connection with conventional inelastic material models can cause ill-posed boundary value problems. These problems can be established by obtaining no unique solution for the resulting algebraic system or by having a strong mesh dependence of the numerical results. This is the consequence of losing ellipticity of the governing field equations. A possible approach to solve these problems is to introduce a non-local field function in the model which includes an internal material length scale. For this purpose a gradient-enhanced free energy function is used for the current continuum damage model from which two variational equations are resulting. Calculations with less effort can be achieved due to the enhancement of the free energy function in comparison to other approaches. The mentioned model is applied to a material with locally varying damage properties (yield limits). Furthermore, the model is able to describe crack propagation in cases of completely damaged material. Therewith, a matrix material including precipitates, such as carbides, is modeled. This allows to investigate ship screws, which usually exhibit the mentioned composition, with regard to the influence of cavitation. Cavitation describes the implosion of risen vapor bubbles, whereby the impact on screws causes heavy damages which can lead to a complete destruction. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

Description: For a reliable prediction of crack paths, on the one hand the accurate calculation of crack tip loading quantities is inevitable, on the other hand orthotropic features of the fracture toughness need to be taken into account. The interplay of crack tip loading and material response due to fracture is still unclear and seems to have a crucial effect on crack path predictions. Numerical tools for the accurate calculation of crack tip loading quantities using path-invariant J-integrals and interaction integrals (I-integral) are presented. Here, global approaches are beneficial when considering crack tips approaching other crack faces or internal boundaries. Curved crack faces have to be taken into account and special treatment regarding crack face integrals is necessary. Experimental investigations are carried out at standard CT-specimens of rolled aluminum alloy Al-7075 exhibiting a directional orthotropy of the fracture toughness. Considering that property, the numerically predicted crack paths based on FE calculations show very good agreement with subcritically grown paths obtained from experiments. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

Description: Due to the different coefficients of thermal expansion of aluminium and silicon, high residual stresses of second order occur in Al-Si alloys depending on the cooling rate during the molding process. In products as for example crank cases made of Al-Si alloys these residual stresses may cause microcracks. In the work at hand measurements of the eigenstresses in the single phases (i.e. residual stresses of second kind) performed via neutron diffractometry are compared to numerical simulations for a specific cooling rate. To this end a three-phase model is presented, which considers the α aluminium, the eutectic aluminium, and the silicon particles. The presented model is able to predict the residual stresses in the single phases within an elastoplastic framework. The simulation of tensile loadings of these structures are compared to experiments. The numerical computations are carried on stochastic geometry models by using a fast solver [1] for the Lippmann-Schwinger integral equation, which is based on the fast Fourier transformation. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

Description: The paper deals with the effect of different stress states on plastic deformations, damage and fracture of ductile materials. To be able to model these effects a continuum damage model has been introduced taking into account the dependence of stress-state on the constitutive equations. The model is based on the introduction of damaged and fictitious undamaged configurations. All parameters appearing in the constitutive equations are stress-state-dependent which can be characterized by the stress intensity, the stress triaxiality and the Lode parameter. Only experiments are not adequate enough to determine all constitutive parameters. Thus, additional series of three-dimensional micro-mechanical simulations of representative volume elements have been performed to get more insight in the complex damage mechanisms. These simulations cover a wide range of stress triaxialities and Lode parameters in tension, shear and compression domains. After all, the results from the micro-mechanical simulations are used to suggest the damage equations and to identify corresponding parameters. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

Description: ABSTRACT There are no studies on stem cells (SCs) and development and differentiation (DD) of the human adrenal glands. The SCs in DD of the adrenal glands were herein investigated histochemically and immunohistochemically in 18 human embryonic adrenal glands at gestational week (GW) 7–40. At 7 GW, the adrenal glands were present, and at 7 GW, numerous embryonic SCs (ESCs) are seen to create the adrenal cortex. The ESCs were composed exclusively of small cells with hyperchromatic nuclei without nucleoli. The ESCs were positive for neural cell adhesion molecule, KIT, neuron-specific enolase, platelet-derived growth factor receptor-α, synaptophysin, and MET. They were negative for other SC antigens, including chromogranin, ErbB2, and bcl-2. They were also negative for lineage antigens, including cytokeratin (CK)7, CK8, CK18, and CK19, carcinoembryonic antigen, carbohydrate antigen 19-9, epithelial membrane antigen, HepPar1, mucin core apoprotein (MUC)1, MUC2, MUC5AC, and MUC6, and cluster differentiation (CD)3, CD45, CD20, CD34, and CD31. The Ki-67 labeling index (LI) was high (Ki-67 LI = around 20%). α-Fetoprotein was positive in the ESCs and adrenal cells. The ESC was first seen in the periphery of the adrenal cortex at 7–10 GW. The ESC migrates into the inner part of the adrenal cortex. Huge islands of ESC were present near the adrenal, and they appeared to provide the ESC of the adrenal. At 16 GW, adrenal medulla appeared, and the adrenal ESCs were present in the periphery or the cortex, in the cortical parenchyma, corticomedullary junctions, and in the medulla. The adrenal essential architecture was established around 20 GW; however, there were still ESCs. At term, there are a few ESCs. These data suggest that the adrenal glands were created by ESCs. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: ABSTRACT A mesiodens is the most common type of supernumerary tooth present in conjunction to normal dentition. A mesiodens may commonly occur in the central region of the upper or lower jaw. A mesiodens is different from normal teeth in terms of structure and shape. The aim of this study is to evaluate the micro- and nanoscale structural properties of mesiodens dentin by combined small- and wide-angle X-ray scattering (SAXS/WAXS) and Fourier transform infrared (FTIR) spectroscopy. Five freshly extracted, noncarious mesiodens and five normal dentin disks prepared from human incisor teeth were compared. Using FTIR, the phosphate-to-amide I, carbonate-to-phosphate, and carbonate-to-amide I band area ratios and the crystallinity index were quantified. SAXS/WAXS were used to study the nanostructure of mesiodens. An increase in the mineral content in the mesiodens dentin with respect to the normal group was found. Crystallinity was also significantly increased and the protein content decreased in the mesiodens dentin compared with that of normal dentin. SAXS/WAXS results revealed that mesiodens dentin has a more calcified tissue. Further, SAXS analysis revealed a nonuniform distribution of dentin fibrils in mesiodens. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: ABSTRACT “Snow lotus” is a famous Chinese Materia Medica derived from species of the genus Saussurea (Compositae). To differentiate three representative easily-confused snow lotus herbs, namely, Saussurea involucrata (Kar. et Kir.) Sch.-Bip, Saussurea laniceps Hand.-Mazz., and Saussurea medusa Maxim., macroscopic features of the three herbs were systemically observed, and microscopic features were compared by using ordinary light microscopy, polarized light microscopy and scanning electron microscopy (SEM). The results indicate that, as for macroscopic identification, capitula situation and arrangement, and as for microscopic identification, pollen grains, nonglandular hairs, glandular hairs, and cells of inner surface of the microdiodange can be used to authenticate the three snow lotus herbs. Comprehensive table comparing the characteristics were presented in this study. SEM has been found to provide a number of unique characteristics of pollen grains. Based on the observation of pollen grains, evolution sequence of the three species was speculated. The present method was proven to be efficient, convenient, simple, and reliable, which was successfully applied to the authentication of three snow lotus herbs. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: ABSTRACT Calcium hydroxide [Ca(OH) 2 ] residues in root canals may compromise sealing of filling and endodontic treatment success. The aim of this study was to compare the efficacy of using rotary instrument associated with EndoActivator, EndoVac, passive ultrasonic irrigation (PUI), and conventional needle irrigation (CNI), in Ca(OH) 2 removal from root canal, by means of scanning electron microscopy (SEM) images. Sixty-six human canines were prepared with the Protaper system up to F5 and filled with Ca(OH) 2 . After 7 days, Ca(OH) 2 was removed with rotary instrument F5 associated with the irrigation techniques used in each group ( n = 15): GI (CNI), GII (EndoVac), GIII (EndoActivator) and GIV (PUI). In all groups 15 mL of 2.5% NaOCl and 3 mL of 17% EDTA were used for Ca(OH) 2 removal. The Ca(OH) 2 residues was evaluated by SEM in the middle and apical third using a system of scores. The results were analyzed by the Kruskal-Wallis and Dunn tests ( α = 0.05). None of the techniques completely removed the Ca(OH) 2 from root canals. There was no difference between EndoActivator, EndoVac and PUI ( P 〉 0.05), but the three techniques removed more Ca(OH) 2 than the CNI ( P 〈 0,05), in the middle and apical thirds of the root canal. It was concluded that the rotary instrument combined with EndoActivator, EndoVac, and PUI was shown to be more efficient than the rotary instrument combined with the CNI in removing Ca(OH) 2 from the root canal. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: ABSTRACT Introduction Hormonal fluctuations may influence fibrin structure. During the menstrual cycle, plasma fibrinogen levels change, mainly due to the variations of estrogen. Throughout the menstrual cycle estrogen levels peak twice, first during the mid-follicular phase and then a lower second peak during the luteal phase. Materials and methods In order to investigate the possible changes in the fibrin network throughout the menstrual cycle, the fibrin network ultrastructure of six healthy female participants were studied at different intervals in the menstrual cycle where differences in estrogen levels are prevalent. Blood plasma smears were prepared for scanning and transmission electron microscopy analysis. Results The external and internal structure of the fibrin fibers showed different morphologies throughout the menstrual cycle. The fibrin fibers were smooth during days 1–5. However, during days 12–14 of the menstrual cycle the fibrin fiber morphology started to change, becoming less smooth. During the luteal phase of the cycle (days 20–25), the network appears sticky, where the minor, thin fibers are more prominent between the thick fibers when compared to the menstrual phase. Conclusion The two estrogen peaks of the menstrual cycle coincide with the changes seen in the current qualitative research, where the fibrin morphology changes during the same time as the estrogen peaks occur. Purified fibrinogen confirmed that it is indeed estrogen that causes the altered fibrin network morphology. This research is the first to show ultrastructural changes in fibrin fiber morphology resulting from estrogen changes during the menstrual cycle. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: ABSTRACT The plantaris longus tendon (PLT) in bullfrog develops a fibrocartilage-like tissue in the area that is functionally subject to compressive forces. The aim of this study was to analyze the modifications of the pressure-bearing region in bullfrog PLT with different ages (7, 180, and 1,080 days after the end of metamorphosis) using histomorphometric, ultrastructural and biochemical methods. Weak basophilia and cells with a fibroblastic phenotype were observed in the compression region at 7 days of age. On the other hand, a large area of intense tissue basophilia associated with a chondroblast-like cell population was noted at the other ages. Collagen fibers exhibited a three-dimensional network-like arrangement at all ages. The number of connective tissue cells increased between 7 and 180 days of age and was reduced in older animals. The 180-day-old animals presented a well-developed pericellular matrix rich in proteoglycans. The mean diameter of collagen fibrils increased from 7 to 180 days and was the same at 1,080 days. Glycosaminoglycan content was higher in 7-day-old animals. A higher amount of hydroxyproline was observed at 180 and 1,080 days. The swelling test showed a significant increase of wet weight in 7-day-old animals. In conclusion, the alterations that occur in the pressure-bearing of bullfrog PLT are the result of physiological alterations of the animal with the maturation and aging. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: ABSTRACT Dynamic changes in the spatial distribution of chloroplasts are essential for optimizing photosynthetic capacity under changing light conditions. Light-induced movement of chloroplasts has been widely investigated, but most studies were conducted on isolated tissues or protoplasts. In this study, a two-photon microscopy (TPM) system was adapted to monitor the intracellular 3-dimensional (3D) movements of chloroplasts in intact leaves of plants during dark to light transitions. The TPM imaging was based on autofluorescence of chlorophyll generated by a femto-second Ti:Sapphire laser. All chloroplasts did not exhibit the same motion in response to irradiation variation. In the sub-epidermal mesophyll cells, chloroplasts generally moved away from the surface following blue light treatment, however many chloroplasts did not show any movement. Such spatial heterogeneity in chloroplast motility underlines the importance of monitoring intracellular orientation and movement of individual chloroplasts across intact leaves. Our investigation shows that the 3D imaging of chloroplasts using TPM can help to understand the changes in local photosynthetic capacity in intact leaves under changing environmental conditions. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: ABSTRACT The aim of this study was to evaluate the effectiveness of 17% ethylene-diamine-tetra-acetic acid (EDTA) used alone or associated with 2% chlorhexidine gel (CHX) on intracanal medications (ICM) removal. Sixty single-rooted human teeth with fully formed apex were selected. The cervical and middle thirds of each canal were prepared with Gates Glidden drills and rotary files. The apical third was shaped with hand files. The specimens were randomly divided into two groups depending on the ICM used after instrumentation: calcium hydroxide Ca(OH) 2 +CHX or Ca(OH) 2 +sterile saline (SS). After seven days, each group was divided into subgroups according to the protocol used for ICM removal: instrumentation and irrigation either with EDTA, CHX+EDTA, or SS (control groups). All specimens were sectioned and processed for observation of the apical thirds by using scanning electron microscopy. Two calibrated evaluators attributed scores to each specimen. The differences between the protocols for ICM removal were analyzed with Kruskal-Wallis and Mann-Whitney U tests. Friedman and Wilcoxon signed rank tests were used for comparison between the score of debris obtained in each root canal third. Remains of Ca(OH) 2 were found in all specimens independently of the protocol and ICM used ( P  〉 0.05). Seventeen percent EDTA showed the best results in removing ICM when used alone ( P  〈 0.05), particularly in those associated with CHX. It was concluded that the chelating agent 17% EDTA significantly improved the removal of ICM when used alone. Furthermore, the type of the vehicle associated with Ca(OH) 2 also plays a role in the ICM removal. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: ABSTRACT This article reports the results of a pilot project using Synchrotron Radiation µCT (computer-aided tomography) to examine the distribution of silica within phytoliths from rice husks. Experiments indicate that computed tomography can be used to show how silica accumulates and is distributed in a distinctive zigzag pattern of long epidermal cells that are characteristic of phytoliths from rice husks. This method will help us to understand why the dry ashing method produced much more zigzag pattern of long cells phytoliths from rice husk than did the acid extraction method. Besides, the zigzag morphological pattern exhibited by long epidermal cells is characteristic of this species which makes it useful in the identification of rice husks from archaeological contexts and indicating heating process. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: ABSTRACT The purpose of this study was to elucidate the micro CT findings of tumoral vessels supplied by portal circulation during establishment of hepatic metastasis of colorectal cancer in a mouse model. Hepatic metastases were induced in 15 BALB/c mice through the injection of murine colonic adenocarcinoma tumor cells into the mesenteric vein. Micro-CT imaging of the tumoral vessels was obtained to clarify the microvascular architecture. We evaluated the sinusoidal structure, diameter of the tumoral vessels (DTV) and blood vessel density (BVD) according to tumor sizes ranging from 201 to 3,000 µm in diameter. A total of 116 tumors were observed on day 15 after cell injection. The mean diameter of a normal hepatic sinusoid was 11.7 ± 2.0 µm on micro CT. The DTV supplied by the portal vein of tumors measuring 1,001–1,500 µm in diameter was greater than that of tumors 200–1,000 µm in diameter. The mean BVD from the portal vein gradually decrease according to size of tumor from 201 to 3,000 µm in diameter ( r 2  = −0.584, P  〈 0.01). The characteristics of tumoral vessels supplied by portal circulation during establishment of hepatic colorectal metastases were well visualized with micro-CT imaging. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: ABSTRACT Several scientific reports have shown the effects of Er:YAG laser irradiation on enamel morphology. However, there is lack of information regarding the morphological alterations produced by the acid attack on the irradiated surfaces. The aim of this study was to evaluate the morphological changes produced by acid dissolution in Er:YAG laser irradiated dental enamel. Forty-eight enamel samples were divided into four groups ( n  = 12). GI (control); Groups II, III, and IV were irradiated with Er:YAG at 100 mJ (12.7 J/cm 2 ), 200 mJ (25.5 J/cm 2 ), and 300 mJ (38.2 J/cm 2 ), respectively, at 10 Hz without water irrigation. Enamel morphology was evaluated before-irradiation, after-irradiation, and after-acid dissolution, by scanning electron microscopy (SEM). Sample coating was avoided and SEM analysis was performed in a low-vacuum mode. To facilitate the location of the assessment area, a reference point was marked. Morphological changes produced by acid dissolution of irradiated enamel were observed, specifically on laser-induced undesired effects. These morphological changes were from mild to severe, depending on the presence of after-irradiation undesired effects. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: ABSTRACT The concerns over health and workplace hazards of formalin fixative, joined to its cross-linking of molecular groups that results in suboptimal immunohistochemistry, led us to search for an innovative safe fixative. Shellac is a natural material which is used as a preservative in foods and pharmaceutical industries. This study was undertaken to evaluate the fixation adequacy and staining quality of histopathological specimens fixed in the “shellac alcoholic solution” (SAS), and also to determine the validity of immunohistochemical staining of SAS-fixed material in comparison to those fixed in formalin. Fresh samples from 26 cases from various human tissues were collected at the frozen section room of King Abdulaziz University Hospital, and fixed in SAS fixative or in neutral buffered formaldehyde (NBF) for 12, 18, 24, and 48 h, and processed for paraffin sectioning. Deparaffinized sections were stained with hematoxylin and eosin (H&E) and immunostained for different antigens. The tissues fixed in SAS for 〉18 h showed best staining quality of H&E comparable to NBF-fixed tissues. Comparison of the immunohistochemical staining of different tissues yielded nearly equivalent readings with good positive nuclear staining quality in both fixatives. These findings support the fixation and preservation adequacy of SAS. Furthermore, it was concluded that the good staining quality obtained with SAS-fixed tissues, which was more or less comparable with the quality obtained with the formalin fixed tissues, supports the validity of this new solution as a good innovative fixative. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: ABSTRACT Aquatic mammals underwent morphological and physiological adaptations due to the transition from terrestrial to aquatic environment. One of the morphological changes regards their vision since cetaceans' eyes are able to withstand mechanical, chemical, osmotic, and optical water conditions. Due to insufficient information about these animals, especially regarding their sense organs, this study aimed to describe the morphology of the Humpback whale ( Megaptera novaeangliae) eyeball. Three newborn females, stranded dead on the coast of Sergipe and Bahia, Brazil, were used. Samples were fixed in a 10% formalin solution, dissected, photographed, collected, and evaluated through light and electron microscopy techniques. The Humpback whale sclera was thick and had an irregular surface with mechanoreceptors in its lamina propria. Lens was dense, transparent, and ellipsoidal, consisting of three layers, and the vascularized choroid contains melanocytes, mechanoreceptors, and a fibrous tapetum lucidum. The Humpback whale eyeball is similar to other cetaceans and suggests an adaptation to diving and migration, contributing to the perception of differences in temperature, pressure, and lighting. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: ABSTRACT The aim of this study was to evaluate the erosion-inhibiting effect of two toothpastes on the development of erosion-like lesions, by a confocal laser scanning microscope (CLSM). Forty human enamel blocks were divided into five groups ( n  = 8), in accordance to evaluate the GC MI Paste Plus and Oral B with stannous fluoride, applied as slurries and associated with toothbrush. Specimens were submitted to an erosion challenge from citric acid (0.5%, pH = 2.8), for 5 min, six times a day, alternating in artificial saliva immersions. Reference group was not exposed to treatment. Part of specimens (Groups 02 and 03) was exposed twice daily just to slurries, for 2 min, therefore specimens from Groups 04 and 05 were also abraded, for 30 s. The enamel surfaces were morphological characterized using CLSM images, with mineral loss being measured using the resulting 3D images referenced to an un-challenged portion of the sample. Step values were compared using the one-way ANOVA test. CLSM was shown to be a viable, noncontact, and simple technique to characterize eroded surfaces. The statistical difference in the step size was significant between the groups ( P  = 0.001) and using multiple comparisons a statistically significant protective effect of toothpastes was shown when these were applied as slurries. Although groups submitted to tooth brush showed mineral loss similar to reference control group, due to the damages of abrasion associated. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: ABSTRACT Over the last decade, we have witnessed an outburst of many different optical techniques aimed at breaking the diffraction limit of light, providing super-resolution imaging on intact fixed cells. In parallel, single-molecule detection by means of fluorescence has become a common tool to investigate biological interactions at the molecular level both in vitro and in living cells. Despite these advances, visualization of dynamic events at relevant physiological concentrations at the nanometer scale remains challenging. In this review, we focus on recent advancements in the field of nanophotonics toward nanoimaging and single-molecule detection at ultrahigh sample concentrations. These approaches rely on the use of metal nanostructures known as optical antennas to localize and manipulate optical fields at the nanometer scale. We highlight examples on how different optical antenna geometries are being implemented for nanoscale imaging of cell membrane components. We also discuss different implementations of self-standing and two-dimensional antenna arrays for studying nanoscale dynamics in living cell membranes as well as detection of individual biomolecular interactions in the µM range for sensing applications. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Description: ABSTRACT This study assessed the influence of different endodontic chemical substances on the adhesion of the Epiphany SE/Resilon system (with and without resinous solvent) to radicular dentin walls, using the push-out test and scanning electron microscopy (SEM). Forty-eight root canals of human canines were prepared biomechanically with ProTaper rotary files (crown-down technique) and the radicular dentin was treated with either 17% EDTA, 2% chlorhexidine gel (CHX) or 2.5% NaOCl (control). The root canals were filled with Resilon cones and Epiphany SE sealer with and without resinous solvent. Six groups of eight canals each had their roots sectioned transversally to obtain 1-mm thick slices. Data were subjected to statistical analysis by ANOVA and Tukey's tests. The specimens treated with 17% EDTA (1.59 ± 0.91) presented higher bond strength (P 〈 0.05) than those treated with 2.5% NaOCl (0.93 ± 0.27) and 2% CHX (0.92 ± 0.22). Significantly higher bond strength (P 〈 0.05) was observed when the Epiphany SE was prepared with (1.37 ± 0.78) than without (0.92 ± 0.33) solvent. Adhesive failures were predominant in all groups. SEM analysis showed greater homogeneity of the filling mass when the solvent was added to the sealer. Treatment of root canal walls with 17% EDTA, and addition of a resinous solvent to Epiphany SE produced the highest adhesion to radicular dentin. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.