Well-developed Cell Research Articles

Influence of different postcuring parameters on mechanical properties and biocompatibility of 3D printed crown and bridge resin for temporary restorations

This study analyzed the flexural properties, Vickers hardness, degree of conversion (DC), and cell viability of 3D printed crown and bridge resin postcured using various types of postcuring equipment (PCE). 3D printed specimens were postcured for various times using different types of 3D printing PCE [for 5, 15, and 30 min using LC 3D Print Box (LC), Form Cure (FC), Cure M (CM), and Veltz 3D (VE) devices] and the VALO handheld light-curing (VA) device for 20, 40, and 60 s. Neither the flexural strength (132.27–145.79 MPa) nor the flexural modulus (1.52–1.83 GPa) differed significantly when postcuring for 30 min using the LC, FC, CM, or VE device, or for 20, 40, or 60 s of postcuring using the VA device (p > 0.05). The Vickers hardness was highest after 30 min of postcuring for all groups, and varied significantly with the postcuring time in the LC (p < 0.001) and CM (p < 0.001) groups. DC was significantly higher for the 5-min CM group (84.97 ± 4.02%) than for the GS, 30-min FC, 5-min VE, and 20-s VA groups. Cell viability of the postcured resin specimens was 56.46–92.29%, and varied significantly in the CM and VE groups according to the postcuring time (p < 0.05). Confocal laser scanning microscopy observations showed well-developed cell morphology and numerous cell–cell contacts in all groups except the GS group. This study found that the use of different types of PCE did not significantly affect the flexural properties of 3D printed crown and bridge resin, whereas there were significant variations in DC, Vickers hardness, and cell viability.

Rearrangement of fatigue dislocation structure in a pure-aluminium single crystal associated with change in deformation temperature

ABSTRACT A two-step low-cycle fatigue test on a pure-aluminium single crystal with a single-slip orientation was performed in the full pull–push mode under constant plastic shear-strain amplitude. In the first-step test, a plastic-shear-strain amplitude of 5 × 10-3 within the plateau region of the cyclic stress–strain curve was employed at 77 K. In the second-step test, similar plastic-shear-strain amplitude was employed at room temperature. In the first-step test, the shear-stress amplitude showed initial hardening to saturation. However, in the second-step test, it gradually decreased with an increase in the cumulative plastic-shear strain. After the first-step test, the matrix-vein structure and persistent slip bands (ladder structure) were well developed. The ladder structure transformed into the cell structure in the initial stage of the second-step test, the area fraction of the cell structure gradually increased with an increase in the cumulative plastic shear-strain, and the specimen was entirely covered with the well-developed cell structure at the end of the second-step test.

Effect of Ambient pH on Growth, Pathogenicity, and Patulin Production of Penicillium expansum.

Penicillium expansum is an important postharvest pathogen of pomaceous fruit and a causal agent of blue mold or soft rot. In this study, we investigated the effect of ambient pH on growth, ultrastructure alteration, and pathogenicity of P. expansum, as well as accumulation of patulin and expression of genes involved in patulin biosynthesis. Under different pH, the fungus was routinely cultured and collected for growth, pathogenicity, patulin production, and gene expression studies using transmission electron microscopy, apple inoculation, HPLC, and RT-qPCR methods. Different ambient pH had significant impact on expression of genes and growth factors involved in patulin biosynthesis. Under same range of pH, gene expression profile, growth factors, and patulin accumulation (in vivo and in vitro) all showed similar changing trends. A well-developed cell was observed in addition to upregulation of genes at pH between pH 5.0 and 7.0, while the opposite was observed when pH was too basic (8.5) or too acid (2.5). Additionally, ambient pH had direct or indirect influence on expression of PecreaA, PelaeA, and PepacC. These findings will help in understanding the effect of ambient pH on growth, pathogenicity, and patulin production and support the development of successful methods for combating P. expansum infection on apple fruits.

Peptidic biofunctionalization of laser patterned dental zirconia: A biochemical-topographical approach

A dual approach employing peptidic biofunctionalization and laser micro-patterns on dental zirconia was explored, with the aim of providing a flexible tool to improve tissue integration of restorations. Direct laser interference patterning with a femtosecond Ti:Sapphire laser was employed, and two periodic grooved patterns were produced with a periodicity of 3 and 10 μm. A platform containing the cell-adhesive RGD and the osteogenic DWIVA peptides was used to functionalize the grooved surfaces. Topography and surface damage were characterized by confocal laser scanning (CLSM), scanning electron and scanning transmission electron microscopy techniques. The surface patterns exhibited a high homogeneity and subsurface damage was found in the form of nano-cracks and nano-pores, at the bottom of the valleys. Accelerated tests in water steam were carried out to assess hydrothermal degradation resistance, which slightly decreased after the laser treatment. Interestingly, the detrimental effects of the laser modification were reverted by a post-laser thermal treatment. The attachment of the molecule was verified trough fluorescence CLSM and X-ray photoelectron spectroscopy. Finally, the biological properties of the surfaces were studied in human mesenchymal stem cells. Cell adhesion, morphology, migration and differentiation were investigated. Cells on grooved surfaces displayed an elongated morphology and aligned along the patterns. On these surfaces, migration was greatly enhanced along the grooves, but also highly restricted in the perpendicular direction as compared to flat specimens. After biofunctionalization, cell number and cell area increased and well-developed cell cytoskeletons were observed. However, no effects on cell migration were found for the peptidic platform. Although some osteogenic potential was found in specimens grooved with a periodicity of 10 μm, the largest effects were observed from the biomolecule, which favored upregulation of several genes related to osteoblastic differentiation in all the surfaces.

Morphology and chemical composition of the Koschewnikow gland of the honey bee Apis mellifera (Hymenoptera: Apidae) workers engaged in different tasks

The Koschewnikow gland is associated with the sting apparatus in the honey bee Apis mellifera Linnaeus, 1758, as a potential source of compounds used as an alarm pheromone. This study describes the histology, morphometry and ultrastructure, and chemical composition of the Koschewnikow gland in workers performing different tasks in the A. mellifera colony. The Koschewnikow gland shows well-developed globular secretory cells of class III with those of the nurse and foragers larger and in greater numbers than those of guard bees. At the ultrastructural level, the secretory cells of all worker bees are rich in mitochondria and smooth endoplasmic reticulum. Mitochondria had different ultrastructure among workers with membrane electron-dense granules in nurse and the electron-lucent halo surrounding the organelle in guard bees. Mitochondria in forager workers show degenerative features such as the disappearance of cristae, electron-lucent matrix, and accumulation of electron-dense aggregates. The chemical analyses of the Koschewnikow gland extract showed that of 23 compounds, 13 had different abundances between workers and of these, 10 were found in higher abundance in guard workers. These results suggest that the Koschewnikow gland has a different structure and chemical composition in honey bee workers engaged in different tasks.

Isolation and Identification of Symbiotic Bacteria from &amp;lt;i&amp;gt;Brasenia schreberi&amp;lt;/i&amp;gt; and Analysis of their Polysaccharide Producing Characteristics and Antioxidant Activity

Brasenia schreberi (water shield), a perennial freshwater aquatic plant of the family Nymphaeaceae, is rich in polysaccharides with positive biological activity and potential application value. As an indicator plant of the environment in wetlands, B. schreberi original and wild water environment faced increasing deterioration and has been listed as a critically endangered species in several countries of East Asia. Seeking an alternative method to produce B. schreberi mucilage polysaccharide is of top priority. The morphological structure of the stem and leaf of B. schreberi was studied. Well-developed glandular cells and aerenchyma tissue were observed in the stem and leaves of water shield, which were related to its aquatic habitat and polysaccharide secretion and then three endophytic bacteria were successfully isolated and purified from its stem and leaf and identified as Micromonospora sp. YG-1, Xylariaceae sp. strain UT-X and Psychrobacter pulmonis strain T-15. Symbiotic bacteria from B. schreberi produced polysaccharides with similar spectral peaks and chemical functional groups to those of B. chinensis. Further, analysis of hydroxyl free radicals showed that symbiotic bacteria in water shield had significant antioxidant activity against hydroxyl free radicals. This study provides a theoretical and practical basis for further study using symbiotic bacteria to produce polysaccharides to overcome the environmental limitations of the growth and development of B. schreberi.

Human Amniotic Membrane Enriched with Urinary Bladder Fibroblasts Promote the Re-Epithelization of Urothelial Injury

Culturing cells in three-dimensional systems that include extracellular matrix components and different cell types mimic the native tissue and as such provide much more representative results than conventional two-dimensional cell cultures. In order to develop biomimetic bladder tissue in vitro, we used human amniotic membrane (AM) extracellular matrix as a scaffold for bladder fibroblasts (BFs) and urothelial cells. Our aims were to evaluate the integration of BFs into the AM stroma, to assess the differentiation of the urothelium on BFs-enriched AM scaffolds, and to evaluate the AM as a urothelial wound dressing. First, to achieve the optimal integration of BFs into AM stroma, different intact and de- epithelialized AM (dAM) scaffolds were tested. BFs secreted matrix metalloproteinase (MMP)-1 and MMP-2 and integrated into the stroma of all types of AM scaffolds. Second, to establish urothelial tissue equivalent, urothelial cells were seeded on dAM scaffolds enriched with BFs. The BFs in the stroma of the AM scaffolds promoted (1) the proliferation of urothelial cells, (2) the attachment of urothelial cells on AM basal lamina with hemidesmosomes, and (3) development of multilayered urothelium with expressed uroplakins and well-developed cell junctions. Third, we established an ex vivo model of the injured bladder to evaluate the dAM as a wound dressing for urothelial full-thickness injury. dAM acted as a promising wound dressing since it enabled rapid re-epithelization of urothelial injury and integrated into the bladder tissue. Herein, the developed urothelial tissue equivalents enable further mechanistic studies of bladder epithelial–mesenchymal interactions, and they could be applied as biomimetic models for preclinical testing of newly developed drugs. Moreover, we could hypothesize that AM may be suitable as a dressing of the wound that occurs during transurethral resection of bladder tumor, since it could diminish the possibility of tumor recurrence, by promoting the rapid re-epithelization of the urothelium.

Fibronectin-induced ductal formation in salivary gland self-organization model.

Recent advances in tissue regeneration approaches including 3D organoids, were based on various 3D organogenesis models. However, 3D models are generally technique-sensitive and time-consuming. Thus, we utilized an existing model of submandibular salivary gland (SMG) to modify a simple and highly reproducible in vitro 3D culture model of primary SMG cells self-organization into a well-developed cell spheroid inside Matrigel substrate. We used this model to observe the collective multicellular behavior during spheroid formation. Further, we applied various quantitative approaches including real-time live imaging and immune histochemical image analysis to dissect the cellular dynamics during tissue patterning. On a time-scale of hours, we observed marked size and shape transformations in the developed 3D spheroid which resulted in a spatially-controlled growth differential from the canter to the periphery of the formed aggregates. Moreover, we investigated the effect of fibronectin (FN) on SMG cells self-organization using our simplified culture model. Interestingly, we discovered a novel role of FN in inducing duct-like elongation during initial stages of SMG bud formation. This in vitro model provides an excellent tool for analyzing the intercellular dynamics during early SMG tissue development as well as revealing a novel role of FN in SMG ductal expansion.

Pore structure evolution of low-rank coal in China

In China, low-rank coalbed methane (CBM) resources are in the early stage of exploration. The evolution of pore structure for these coals around the first coalification jump is incomplete. Here systematic experiments were conducted to analyze the reservoir of low-rank coal (lignite and subbituminous coal) from China's major low-rank basins, thus revealing the pore structure evolution of low-rank coal in China. Scanning electron microscopy (SEM) demonstrates that there are obvious differences in the pore types of different rank coals. Well-developed cell lumina provides a large amount of macropore space in coals with Ro < 0.5%. After coal metamorphism and physical compaction, the volume and number of plant tissue pores are reduced, resulting in a significant reduction in macropores. The Fourier transform infrared spectroscopy (FTIR) spectral characteristics indicate that the evolution of chemical structure also has an effect on the pore structure of coal. Due to the low proportion of aromatic nuclei, the high proportion of functional groups and long side chains, when Ro is <0.5%,the spatial structure of coal reservoir is “loose”, resulting in a large surface area. With increasing coal maturity, the side chains gradually decompose and the length decreases, and the aromatic nuclei increase so that the structure becomes more “compact”. With increasing coal rank, the pore size distribution changes significantly. The peak shape of the NMR T2 spectrum shows a series of complex changes from trimodal to bimodal to trimodal and finally to bimodal, indicating that the pore size distribution undergoes continuous changes. With the continuous coalification and physical compaction, the porosity decreases rapidly with vitrinite reflectance increases from 0.42–0.68%, and the adsorption capacity shows an increasing trend with the increase of coal rank under the control of moisture content, pore type, and specific surface area. Understanding the evolution of pore structure in the early stage of coalification will provide a scientific reference and foundation for exploration and development of low-rank CBM.

Cyclic Deformation Microstructure in Heavily Cold-Drawn Austenitic Stainless Steel

Cyclic deformation microstructure of the heavily cold-drawn austenitic stainless steel is significantly influenced by the spacing between mechanical twins introduced by prior cold drawing. Well-developed dislocation cells form between mechanical twins with the spacing larger than about 800 nm. Persistent slip band (PSB)-like structure with ladders takes place between mechanical twins spacing from 300 to 800 nm. Few dislocations occur between neighboring mechanical twins with spacing less than about 100 nm. Pre-existing mechanical twins and deformation bands segment austenitic grains, facilitating multi-slip and consequently suppressing PSB formation.

Characteristics of pericytes in diethylstilbestrol (DES)-induced pituitary prolactinoma in rats.

Prolactinomas are the most common tumor of the human pituitary. They result in excessive prolactin secretion and important changes in the vasculature. Pericytes are perivascular cells associated with capillaries and have crucial roles in physiological and pathological neovascularization. We previously reported that pericytes produce type I and III collagens in the anterior pituitary of adult rats. In addition, pituitary pericytes contained well-developed cell organelles and actively synthesized collagens during early postnatal development. However, the characteristics of pericytes in pituitary tumors are unclear. In this study, we used diethylstilbestrol (DES)-treated rats as an animal model of prolactinoma. Using five common pericyte markers, more pericytes were observed in rats treated with DES for 3 months (prolactinoma) compared to the control. Transmission electron microscopy revealed that attached and semidetached pericytes exhibited active cell organelles. Moreover, we identified pericyte migration between capillaries. Although the fine structure of pituitary pericytes was active in prolactinoma, expressions of type I and III collagen mRNAs were greatly diminished. In sum, the characteristics and functions of pericytes were altered in pituitary tumors. This study is the first to clarify fine structural changes of pericytes in rat prolactinomas and improves our understanding of the function of pericytes under pathological conditions.

Effects of Cyclic and Monotonic Deformations on Nonlinear Ultrasonic Response of Austenitic Stainless Steel: A Comparative Study

The effect of plastic deformations on the nonlinear ultrasonic response in austenite stainless steel was investigated under the tensile, asymmetric cyclic, and symmetric cyclic loadings. Nonlinear ultrasonic wave measurement was performed on the interrupted specimens. Results show that cyclic and monotonic plastic deformations lead to the significantly different acoustic nonlinear response. The increase of dislocation density and martensite transformation causes the increase of acoustic nonlinearity. By contrast, the well-developed cell structures decrease the acoustic nonlinear response. Under the asymmetric cyclic loading condition, the lightly decrease of acoustic nonlinearity is caused by the development of cell structures, while the slight increase of acoustic nonlinearity should be attributed to the increase of martensite transformation. Comparatively, the severe increase of acoustic nonlinearity during the first stage under symmetric cyclic loading is ascribed to the fast generation of dislocation structures and martensite transformation.

Inflorescences of Mauldinia sp. (Lauraceae) and associated fruits from the Cenomanian of Languedoc Roussillon, France

Inflorescences of Mauldinia (Lauraceae) are described from the middle Cenomanian Pauletian facies of Gard, Languedoc-Roussillon, south-eastern France. This is the first record of the genus from this part of Europe. Mauldinia sp. is described based on peduncles and lateral units. Isolated, slender peduncles show spirally arranged scars or rarely attached lateral units. Isolated lateral units consist of cladode-like structures showing up to seven flower/fruit scars. Some isolated fruits were found associated with peduncles and lateral units. Fruits are ovoid fruits contain a single, elongated seed. The pericarp consists of epicarp, mesocarp and endocarp. The seed consists of two cotyledons containing well-developed reserve cells. Mauldinia sp. from Gard differs from known Mauldinia species by having longer internodes along the peduncle and by the shape of the lateral units. Sedimentological and palaeontological evidence suggests that Mauldinia sp. from Gard grew in a protected, littoral environment with limited marine influence. This report provides new information to the relatively poorly known Cretaceous record of angiosperms in France. The occurrence of Mauldinia in the lower Upper Cretaceous of Gard corroborates the widespread occurrence of the genus in marginal littoral environments during the mid-Cretaceous.

Variation in growth pattern and morphological appearance of primary monolayer cultures of chondrocytes and neural cells isolated from the chick embryo at different stages

Aim: This study was an attempt at investigating the variation in growth and morphology of primary avian chondrocyte and neural cell cultures established under standard laboratory conditions. Methods: For establishing chondrocyte cultures, the tibia were dissected from chick embryos that were 12 (E12), 14 (E14) and 15 (E15) days old. For the neural cell culture initiation, the two lobes of the forebrain were dissected from chick embryos that were 4 (E4), 8 (E8) and 12 (E12) days old. The final characterization of the cells was performed by H&E and CFV staining. Results: In the chondrocyte cultures, two forms of morphology were observed which is reversible in process.The primary variation evaluated in chondrocytes cultures was the effect of the media on the state of the cells. Based on whether the cells were cultured in DMEM or MEM, there was a difference in the transformation of the attached cells from the differentiated to de-differentiated forms. The primary variation examined in neuron cultures was the embryonic age of the tissue and the effect that it had on the proliferation and neurite formation of the cells. E8 embryo neural cells cultures result in well-developed cells with neurite formation along with axonal and dendritic outgrowths with highly complex interconnections between them. Conclusion: Ultimately, this study demonstrated the composition of culture media had an effect on the morphological appearance of the chondrocytes, as well as, confirmed that the culture of primary neurons is best performed using cells from an E8 embryo.

Observation and investigation of three endosperm transport tissues in sorghum caryopses.

Endosperm transport tissues in sorghum caryopses include endosperm transfer cells, endosperm conducting cells, and the embryo surrounding region. To elucidate the structural changes of these tissues and their relationship with the caryopsis development, sorghum caryopses were analyzed at different days after pollination using light, fluorescence, and electron microscopy. The following results were obtained: post-phloem maternal tissues included the placentochalaza and the nucellar projection-like nucellus. Well-developed endosperm transfer cells exhibited very evident flange-type wall ingrowths. Very few wall ingrowths were present in the initially developed endosperm transfer cells when the level of sucrose from the initially developed vascular system was low. At the middle stage of caryopsis development, the level of sucrose from the well-developed vascular system was high. Endosperm transfer cells increased in both area and layer amount, and their wall ingrowths increased in both length and density. Later in caryopsis development, the level of sucrose from the degenerated vascular system was low and wall ingrowths distorted in the degenerated endosperm transfer cells. Endosperm conducting cells primarily occupied the most part of endosperm, but decreased gradually because the upper part transformed into the starchy endosperm and the lower part degenerated to give space to the embryo growth. Although the embryo surrounding region initially enveloped the small embryo, it rapidly degenerated and finally disappeared. Our data showed that (1) the caryopsis vascular system influenced the differentiation of endosperm transfer cells by controlling the sugar levels (2) and configuration of endosperm transport tissues were probably altered to favor the growth of filial tissues.

Structural Features of Some Wheat (Triticum Spp.) Landraces/Cultivars Under Drought and Salt Stress

Seven local landraces of common and durum wheat (Triticum aestivum L. and T. durum L.) from the arid and semi-arid areas of the Sultanate of Oman were examined for specific leaf and stem structural features for water conservation. On the basis of shoot fresh and dry weights (g plant−1), degree of tolerance to drought and salt stresses in these wheat landraces/cultivars can be ranked as S-24 > J-305 > Sarraya > Senain > Cooley > MH-97 > Missani>Hamira > Shwairaa. Modifications related to water conservation were found to be high degree of sclerification, succulence in leaf and stem, low resistance to water conductance in vascular tissue, and pubescence on leaf surface. The salt and drought tolerant cultivar S-24 showed high proportion of chlorenchyma and intensive sclerification in stem structure, and well-developed bulliform cells and dense pubescence on the leaves. These modified features were poorly developed in lesser stress tolerant Omani wheat landraces like Hamira and Shwairaa. Accession Senain also showed stem succulence (solid stem), an important xeromorphic feature. Structural modifications in landrace Missani were found to be increased sclerification in vascular tissue and high number of metaxylem vessels and high proportion of parenchyma in stem, and highly developed bulliform cells in leaf. Overall, the promising anatomical traits in highly stress tolerant landraces/cultivars were chlorenchyma in stem, rigorous sclerification in parenchyma and around vascular tissue, stem and leaf succulence, and enhanced ratio of major conducting tissue.

Influence of pressure on the microstructural evolution of Ta during shear deformation

The effect of high pressure on the mechanical behavior and accompanying microstructural evolution in Ta has been investigated. Thin-foil Ta samples were deformed while being subjected to pressures in the 1–5 GPa range in a modified opposed-anvil Bridgman apparatus. Examination of deformed microstructures revealed similar changes in texture in all samples, independent of pressure. However, dislocation structures are observed to change from entanglements to well-developed dislocation cells with increasing pressure. Dislocation dynamics simulations are used to explain the experimental results.

English

epidermoid cyst may get secondarily infected, may lead to pressure over the underlying bone and rarely undergoes malignant transformation. Epidermoid cysts have a welldeveloped granular cell layer and are lined by stratified squamous epithelium; rarely, pseudostratified ciliated columnar epithelium may be present on the cyst wall3. The cyst wall can have dystrophic type calcification. Excision is the treatment of choice2. The aim was to study the occurrence of giant sebaceous cysts.

Changes in fine structure of pericytes and novel desmin-immunopositive perivascular cells during postnatal development in rat anterior pituitary gland

Pericytes are perivascular cells associated with capillaries. We previously demonstrated that pericytes, identified by desmin immunohistochemistry, produce type I and III collagens in the anterior pituitary gland of adult rats. In addition, we recently used desmin immunoelectron microscopy to characterize a novel type of perivascular cell, dubbed a desmin-immunopositive perivascular cell, in the anterior pituitary. These two types of perivascular cells differ in fine structure. The present study attempted to characterize the morphological features of pituitary pericytes and novel desmin-immunopositive perivascular cells during postnatal development, in particular their role in collagen synthesis. Desmin immunostaining revealed numerous perivascular cells at postnatal day 5 (P5) and P10. Transmission electron microscopy showed differences in the fine structure of the two cell types, starting at P5. Pericytes had well-developed rough endoplasmic reticulum and Golgi apparatus at P5 and P10. The novel desmin-immunopositive perivascular cells exhibited dilated cisternae of rough endoplasmic reticulum at P5-P30. In addition, during early postnatal development in the gland, a number of type I and III collagen-expressing cells were observed, as were high expression levels of these collagen mRNAs. We conclude that pituitary pericytes and novel desmin-immunopositive perivascular cells contain well-developed cell organelles and that they actively synthesize collagens during the early postnatal period.

Plan B for Stimulating Stem Cell Division

Plan B for Stimulating Stem Cell Division