Role In Morphological Changes Research Articles

In the Era of Molecular Pathology, the Role of Morphological Changes in Megakaryocytes in Bone Marrow Aspiration in Cases of Isolated Thrombocytopenia

In the Era of Molecular Pathology, the Role of Morphological Changes in Megakaryocytes in Bone Marrow Aspiration in Cases of Isolated Thrombocytopenia

MaEng1, an endo-1,3-glucanase, contributes to the conidiation pattern shift through changing the cell wall structure in Metarhizium acridum

Microcycle conidiation has displayed the greater potential than normal conidiation in large-scale production of mycopesticides. Fungi require partial hydrolysis of the cell wall to achieve the necessary plasticity during their morphological changes. Therefore, various cell wall-associated hydrolases are crucial for fungal morphogenesis. Eng1, as an endo-β-1,3-glucanase, is involved in the cell separation of fungi, but its role in morphological changes of entomopathogenic fungi is not yet clear. Here, the endo-β-1,3-glucanase gene MaEng1 was characterized in the model entomopathogenic fungi M. acridum. MaEng1 possesses a typical carbohydrate hydrolase domain and belongs to the GH81 family. The functions of MaEng1 in fungal growth, stress tolerance, pathogenicity, and conidiation capacity were analyzed using targeted gene disruption. The results displayed that the absence of MaEng1 does not affect the fungal growth, stress tolerances, and pathogenicity in M. acridum. However, the knockout of MaEng1 led to the normal conidiation of M. acridum on the SYA medium, which can induce the microcycle conidiation. Moreover, the content of β-1,3-glucan in the cell wall of the MaEng1-disruption strain were significantly reduced and the exposures of β-1,3-glucan on the surface of the mature conidia and mycelia in ΔMaEng1 were declined, indicating that MaEng1 contributes to the conversion of conidiation mode in M. acridum by affecting the cell wall structure.

Atrophy in subcortical gray matter in adult patients with moyamoya disease

BackgroundAcute cerebrovascular accidents, long-term hypoperfusion, and/or remote neuronal degeneration may lead to structural alterations in patients with moyamoya disease (MMD). This study sought to comprehensively investigate the distribution characteristics of subcortical gray matter volume and their correlations with angiographic changes in the intracranial artery in patients with MMD. MethodOne hundred forty-two patients with MMD and 142 age- and sex-matched healthy controls underwent 3-dimensional high-resolution structural magnetic resonance imaging. Volumes of subcortical gray matter and subregions of the hippocampus and amygdala were calculated, and the degree of stenosis/occlusion of intracranial arteries in patients with MMD was evaluated on MR angiography.ResultsVolume reductions in the thalamus, caudate, putamen, hippocampus, amygdala, pallidum, and nucleus accumbens were found in patients with MMD. Hippocampal subfields and amygdala subnuclei in patients with MMD showed distinct vulnerability, and morphological alterations in specific subregions were more obvious than in the whole hippocampus/amygdala. Volume loss in several subcortical areas was related to disease duration and intracranial arterial changes.ConclusionsOur findings revealed structural alteration patterns of subcortical gray matter in MMD. The specific atrophy in subregions of the hippocampus and the amygdala suggested potential cognitive and affective impairments in MMD, which warrants further investigation. Chronic cerebral hemodynamic alterations in MMD may play a pivotal role in morphological changes in subcortical areas.

Морфологический анализ семенников в оценке фертильности мышей после однократного острого γ-облучения разными дозами

Introduction. Radiation therapy for malignant neoplasms can have detrimental effects on male reproductive health. Little is known about the role of morphological changes in the testes when assessing the fertility after exposure to lethal and sublethal doses. The research aimed to investigate the impact of acute γ-irradiation at various doses on testicular morphology, spermatozoa, and fertility potential in mice through a comparative morphological analysis. Materials and methods. We subjected BALB/c mice to acute γ-irradiation at doses of 1 and 6 Gy using the IGUR device (Cs137, dose rate of 0.85 Gy/min). We studied the structural state of the testes and spermatozoa. Morphological examination was performed using optical microscopy of histological slides with digital microphotography (n=180). Fertility potential was assessed by mating irradiated males (n=200) with intact mature females (n=400). Results. During the course of the experiment, which lasted from 16 to 120 days, we observed significant morphological changes in the testes and spermatozoa of the experimental groups. On day 62, the number of seminiferous tubules exhibiting destruction at 1- and 6-Gy doses was the highest. This destruction was characterized by a 2- to 4-fold increase in the desquamation of germ cells, a 3- to 6-fold increase in the desquamation of the spermatogenic epithelium, and a 2- to 10-fold increase in the desolation of the seminiferous tubules, respectively. The maximum decrease in the number of spermatozoa was to 68 and 44% at doses of 1 and 6 Gy, respectively. The number of live spermatozoa decreased to 62% and 25%; sperm motility dropped by 21% and 100%. We detected an increase in the number of pathological forms of spermatozoa by 40% and 3 times at doses of 1 and 6 Gy, respectively. An increase in the total embryonic and induced post-implantation mortality in females fertilized by irradiated males was noted at all stages of spermatogenesis (p<0.05). At a 6-Gy dose, we detected a temporary sterility at the stages of spermatids and spermatocytes. Conclusion. The degree and depth of morphological changes in the testes and spermatozoa are dose-dependent, the most pronounced changes being at a 6-Gy dose causing temporary sterility. A compensatory-restorative reaction from spermatogenesis was revealed. Keywords: γ-irradiation, spermatogenesis, spermatozoon, fertility

Modeling Operando Electrochemical CO2 Reduction.

Since the seminal works on the application of density functional theory and the computational hydrogen electrode to electrochemical CO2 reduction (eCO2R) and hydrogen evolution (HER), the modeling of both reactions has quickly evolved for the last two decades. Formulation of thermodynamic and kinetic linear scaling relationships for key intermediates on crystalline materials have led to the definition of activity volcano plots, overpotential diagrams, and full exploitation of these theoretical outcomes at laboratory scale. However, recent studies hint at the role of morphological changes and short-lived intermediates in ruling the catalytic performance under operating conditions, further raising the bar for the modeling of electrocatalytic systems. Here, we highlight some novel methodological approaches employed to address eCO2R and HER reactions. Moving from the atomic scale to the bulk electrolyte, we first show how ab initio and machine learning methodologies can partially reproduce surface reconstruction under operation, thus identifying active sites and reaction mechanisms if coupled with microkinetic modeling. Later, we introduce the potential of density functional theory and machine learning to interpret data from Operando spectroelectrochemical techniques, such as Raman spectroscopy and extended X-ray absorption fine structure characterization. Next, we review the role of electrolyte and mass transport effects. Finally, we suggest further challenges for computational modeling in the near future as well as our perspective on the directions to follow.

The role of morphological changes in Microcystis adaptation to nutrient availability at the colonial level

Colony formation is a key trait facilitating the formation of Microcystis blooms. However, the role of morphological changes (e.g., colony size and tightness) in the adaptation to nutrient availability is not fully understood. In this study, we analyzed the morphological changes under both nutrient sufficiency and deficiency. Accordant morphological changes were found with both an isolated colonial strain and mixed field colonies. Colonies that were limited by nutrients became bloated and uncompacted structures, and this change was more pronounced under N deficiency. This looser morphology increased the availability of intra-colony light and relieved the size effect. When nutrients were sufficient, small colonies emerged, which helped to maintain rapid growth (0.32 day−1). Our study highlighted probable role of morphological variations in: (1) diminishing intra-colony self-shading when facing nutrient deficiency; and (2) enlarging the population under high trophic levels by generating daughter colonies. These roles were also verified using field data from Lake Taihu, which further indicated that the seasonal succession of morphospecies was probably the result of adaptive morphological changes. Adaptive morphological changes offer advantages against fluctuations in nutrient availability, which should be considered when attempting to restrain bloom formation.

ФАКТОРЫ МАГНИТНО-ИМПУЛЬСНОГО ВОЗДЕЙСТВИЯ, ВЛИЯЮЩИЕ НА МОРФОЛОГИЧЕСКИЕ ИЗМЕНЕНИЯ БИОЛОГИЧЕСКОЙ КЛЕТКИ

Recently, research on the use of pulsed magnetic fields (PMF) of high intensity in biology and medicine has been expanding. To understand the morphological changes that occur in a cell under the influence of a PMF, the article considers the factors of such an impact: magnetic, mechanical and thermal. The relationship between the structure of the cell and the factors of influence is given. The parameters of the PMF that affect these factors and their predictive role in morphological changes in the cell are described. The material presented in the article will make it possible to reasonably outline the directions of research and purposefully form a search for morphological changes.

Role of EBAF/Nodal/p27 signaling pathway in development of placenta in normal and diabetic rats

Placentas control the maternal–fetal transport of nutrients and gases. Placental reactions to adverse intrauterine conditions affect fetal development. Such adverse conditions occur in pregnancies complicated by diabetes, leading to alterations in placental anatomy and physiology. In this study, streptozocin (STZ) injection produced sustained hyperglycemia during pregnancy in rats. Hyperglycemic pregnant rats had gained significantly less weight than normal pregnant rats on embryonic day 15.5. We investigated the influence of diabetes on placental anatomy and physiology. Compared with controls, the diabetic group had a markedly thicker junctional zone at embryonic day 15.5. To explore a mechanism for this abnormality, we examined Nodal expression in the junctional zone of control and diabetic groups. We found lower expression of Nodal in the diabetic group. We then investigated the expression of its target gene p27Kip1 (p27), which is related to cell proliferation. In vitro, Nodal overexpression up-regulated p27 protein levels while interfered EBAF up-regulated p27. In vivo, the expression of p27 was lower in diabetic compared with normal rats, and localization was similar between the two groups. In contrast, a higher expression of PCNA was found in diabetic versus normal placenta. Endometrial bleeding associated factor (EBAF), an up-stream molecular regulator of Nodal, was expressed at higher levels in placenta from diabetic versus normal rats. Based on these results, we speculate that the EBAF/Nodal/p27 signaling pathway plays a role in morphological change of diabetic placenta.

Possible neurogenic mechanisms in sudden infant death syndrome

Background.Sudden infant death syndrome (SIDS) is the unexpected, non-violent death of an apparently healthy child aged 7 days to 1 year, in which the anamnesis and autopsy data do not reveal the cause of the fatal outcome. Researchers have not come to a consensus on the thanatological role of morphological changes in the brain.Aim.To determine pathomorphological changes in the brain in the case of sudden death syndrome in children.Material and methods.Forensic medical studies of 118 deaths of healthy children who died suddenly for the period 20082017 were carried out and analyzed on the territory of the Stavropol region. Autopsy material was divided into groups: the main group (1) consisted of 74 observations (62.8%), where SIDS was the main final sectional diagnosis. The comparison group (2) consisted of 44 (37.2%) observations; the children died suddenly at home as a result of viral-bacterial pneumonia. For the control, the third group was formed (3), which included 45 observations, where the death of children occurred as a result of drowning and carbon monoxide poisoning.Results.A histological examination of pieces of the brain in the case of sudden death syndrome revealed the foci of angiomatosis of the vessels of the pia mater and brain matter with the normal structure of the elastic membrane of the arteries, the effects of glial proliferation in the subependymal region of the lateral ventricles and subcortical formations. In the medulla oblongata, in a detailed study of the posterior (vegetative) nucleus of the vagus nerve, degenerative changes in neurons were detected in the form of chromatolysis and karyolysis, a glial reaction of the neuronophagic type.Conclusion.Pathomorphological changes in the brain stem may be due to combined intrauterine hypoxic and intrapartum traumatic factors, which, potentiating each other, lead to dysregulation of the respiratory rhythm with the development of a fatal outcome during sleep.

The role of morphological changes in algae adaptation to nutrient stress at the single-cell level

Individual cell heterogeneity within a population can be critical to its peculiar function and fate. Conventional algal cell-based assays mainly analyze the average responses from a population of algal cells. Therefore, the mechanisms through which changes in population characteristics are driven by the behavior of single algal cells are still not well understood. Algal cells may modulate their physiology and metabolism by changing their morphology in response to environmental stress. In this study, an algal single-cell culture and analysis system was developed to investigate the potential role of morphological changes by algal cells during adaptation to nutrient stress based on a microwell array chip. The surface-to-volume ratio of Microcystis aeruginosa (M. aeruginosa) and the volume of Scenedesmus obliquus (S. obliquus) significantly increased with increasing culture time under nutrient stress. The eccentricity of M. aeruginosa and S. obliquus gradually increased and decreased, respectively, with increasing culture time, indicating that the morphology of M. aeruginosa and S. obliquus became increasingly irregular and regular, respectively, under nutrient stress. There were significant correlations between the morphological characteristics and physiological characteristics of M. aeruginosa and S. obliquus under nutrient stress. In M. aeruginosa, an increased surface-to-volume ratio facilitated a high specific fluorescence intensity, specific Raman intensity, and maximum electron transport rate. In S. obliquus, increased cell volume enhanced nutrient absorption, which facilitated a higher specific growth rate. M. aeruginosa and S. obliquus adopted different adaptation strategies in response to nutrient stress based on morphological changes. These findings facilitate the development of management strategies for controlling harmful cyanobacterial blooms.

Mbp1, a component of the MluI cell cycle box-binding complex, contributes to morphological transition and virulence in the filamentous entomopathogenic fungus Beauveria bassiana.

The Mbp1 protein functions as a DNA-binding protein in the MluI cell cycle box-binding complex and plays significant roles in yeast development. In this study, an ortholog of yeast Mbp1, BbMbp1, was characterized in a filamentous insect mycopathogen, Beauveria bassiana. BbMbp1 plays an important role in morphological changes under aerial and liquid environments. On the aerial surface, BbMbp1 was indispensable for the biogenesis of conidiophores and conidiation. Under submerged conditions, the ∆BbMbp1 mutant displayed abnormal spore-producing structures, with a dramatic decrease in blastospore yield (~95%). The virulence of the ∆BbMbp1 mutant was notably weakened, which might be due to the defect in in vivo blastospore formation in the insect. Moreover, disruption of BbMbp1 resulted in a substantial reduction in hyphal growth on cadavers. Comparative transcriptomics revealed that BbMbp1 mediated different transcriptomes during the formation processes of conidia and blastospores. Yeast one-hybrid assays demonstrated that BbMbp1 was required for transcriptional control of a cell wall protein gene, BbCwp, and an integral membrane protein gene, BbImp that played significant roles in conidiation and blastospore formation respectively. Our results demonstrate that BbMbp1 contributes to the morphological transitions in the pathogenic and saprophytic growth of B. bassiana via different genetic pathways.

Hydrodynamics, erosion and accretion of intertidal mudflats in extremely shallow waters

Intertidal flats are shallow-water environments that undergo cyclical variations in water depth, leading to a frequent occurrence of extremely shallow water stages (ESWS; water depths <0.2 m). However, relatively little is known about the hydrodynamic conditions and erosion–accretion processes during ESWS, because the water depth is too shallow to measure in situ sediment dynamic processes using traditional methods. To address this gap, based on in situ measurements with four advanced instruments, we quantified the hydrodynamic conditions, erosion and accretion during ESWS in calm weather conditions on a highly turbid intertidal flat in Jiangsu coast, China. Our results revealed that marked erosion and accretion occurred during ESWS at the flood and ebb tidal stages, respectively. The resulting bed-level changes were three times greater during ESWS than relatively deep water stages (RDWS; water depths >0.2 m), and the rate of change was an order of magnitude faster than during RDWS. This larger and faster bed-level change occurred even though the ESWS duration only accounted for 10% of the entire tidal cycle. This result occurred because the bed shear stress due to combined current–wave action during ESWS, was, on average, two times higher than during RDWS at the flood stage causing more extensive erosion. Whereas during the ebb stage, this shear stress during ESWS was only half of that during RDWS resulting in greater accretion. The main implications of these results are that, because ESWS occur frequently (twice every tide) and are associated with large bed shear stress and bed-level changes, these conditions are likely to play an important role in morphological changes of intertidal flats. Our study shows that ESWS have a key influence on intertidal flat hydrodynamics and sediment dynamics. Thus our results are the basis for an improved understanding of the coastal morphodynamic processes on intertidal flats.

ARHGEF4-mediates the actin cytoskeleton reorganization of hepatic stellate cells in 3-dimensional collagen matrices

ABSTRACTThe actin cytoskeleton of hepatic stellate cells (HSCs) is reorganized when they are cultured in 3D collagen matrices. Here, we investigated the molecular mechanism of actin cytoskeleton reorganization in HSCs cultured in 3D floating collagen matrices (FCM) compared to those on 2D polystyrene surfaces (PS). First, we found that the generation of dendritic cellular processes was controlled by Rac1. Next, we examined the differential gene expression of HSCs cultured on 2D PS and in 3D FCM by RNA-Seq and focused on the changes of actin cytoskeleton reorganization-related molecular components and guanine nucleotide exchange factors (GEFs). The results showed that the expression of genes associated with actin cytoskeleton reorganization-related cellular components, filopodia and lamellipodia, were significantly decreased, but podosome-related genes was significantly increased in 3D FCM. Furthermore, we found that a Rac1-specific GEF, ARHGEF4, played roles in morphological changes, migration and podosome-related gene expression in HSCs cultured in 3D FCM.Abbreviations: 2D PS: 2-dimensional polystyrene surface; 3D FCM: 3-dimensional floating collagen matrices; ARHGEF4: Rho guanine nucleotide exchange factor 4; ARHGEF6: Rho guanine nucleotide exchange factor 6; GEF: guanine nucleotide exchange factor; HSC: hepatic stellate cell

Computational model for tactile sensing system with wrinkle’s morphological change

ABSTRACTWe previously developed Wrin’Tac, a tactile sensing system that can select sensing modalities by changing its morphology. In this paper, we present a computational model to estimate a wrinkle’s morphology and predict the output of embedded sensing elements in both static indentation and sliding action cases. We evaluated the wrinkle shape and the posture of the sensing element by calculating its height. The wrinkle’s mechanical change is assessed by ascertaining its stiffness under vertical indentation by a spherical indenter. The output voltages of the sensor under static indentation are calculated by the proposed model, and the experimental values have error less than 10%, which validates the accuracy of our proposed model. For dynamic sliding action, this proposed model clarified the capability of wrinkle morphology in an evaluation of such sliding action’s characteristics as the sliding direction and velocity. We also identified the role of the wrinkle’s morphology in the sensor’s sensitivity under different conditions of dynamic sliding motion, implying that this sensing system may select suitable sensitivity for specific sensation tasks. We expect this work to pave the way for assessing the role of morphological changes to tactile sensation and developing soft active tactile sensing systems.

Temporal and Spatial Variations of Zarrineh-Rood River Morphology Using RS and GIS

Identification of changes and their effects on the morphology of river bed and riverside lands is a necessity for river management. This study focuses to identify the trend of river morphological evolution and changes in the riverbed territory at the final 25-kilometer downstream section of the Zarrineh-rood River leading to Urmia Lake in West Azerbaijan during the last 50 years using aerial photos taken in 1955 and 1967, topography maps produced in 1996, and SPOT satellite images taken in 2011 with field survey. They were interpretated to 3 land types of sandy beaches, permanent riverbed and sandy barriers. Distinguished land type maps overlayd and compared using GIS ILWIS software. Surface area of land types, river meandering and sinusoidal coefficients were calculated and the trend of the river interpretated. Results showed that the area of the riverbed territory has reduced form 561.1 to 221.3 ha, and the riverbed morphology and the shape of river bends have evolved. From 1967 to 2011, natural features such as sand dunes inside the riverbed have reduced from 13.68 to 2.86 ha, which indicates high fluctuations of discharge and changes in hydrological and hydraulic conditions of the river. The number of meanders has decreased from 4 to 3 and the riverbed has become straighter and more arterial. Land types surface area of sandy beaches decreased from 503.66 to 140.78, permanent riverbed increased from 54.83 to 77.68 and Sand dune is almost stable. The sine coefficient of the river is about 1.5 that indicates river classified as meandering. Deposition plays a mail role in morphological changes. 60% reduction in the riverbed territory is alarming, and current riverbed with its sedimentation prone conditions will not be able to discharge floods with average and above average return period. The most effective factors in morphological changes are the changes in hydrological regime because of dam construction, reduction of runoff, and accumulation of sediment loads on the riverbed.

Morphological features eutopic endometrium in women with adenomyosis and chronic pelvic pain syndrome.

Background. Chronic pelvic pain syndrome is one of the most frequent pathologies that reduce quality of woman`s life. The main reason for its occurrence is gynecological diseases (extragenital endometriosis, adenomyosis, uterine leiomyoma). But role of morphological changes in the endometrium for the occurrence of these diseases is still unexplored. Objective. Assess the links between morphological and immunohistochemical (markers ER, PGR, Ki-67, VEGF, COX-2, NF) features and the level of pain on VAS. Methods. 10 samples were divided according to expression of investigated marker in glands (ER, PGR, Ki-67, VEGF, COX-2, NF) and in stroma (ER, PGR, Ki-67). Rating staining immunohistochemical markers was conducted in at least 10 fields of view. Statistical processing of the data included non­parametric tests. Results. We observed heterogeneous expression of ER, PGR, more importat role of high level expression PRG in stroma, increased proliferative activity in glands is focal in the most cases. Expression of VEGF is often higher, when the level of VAS is up. Conclusion. Formation of the CPP and adenomyosis is associated with hyperplastic processes of endometrium , increased proliferative activity , and severe expression of COX - 2 ( p &lt; 0.05 ).

Microtubule aging probed by microfluidics-assisted tubulin washout.

Microtubules switch stochastically between phases of growth and shrinkage. The molecular mechanism responsible for the end of a growth phase, an event called catastrophe, is still not understood. The probability for a catastrophe to occur increases with microtubule age, putting constraints on the possible molecular mechanism of catastrophe induction. Here we used microfluidics-assisted fast tubulin washout experiments to induce microtubule depolymerization in a controlled manner at different times after the start of growth. We found that aging can also be observed in this assay, providing valuable new constraints against which theoretical models of catastrophe induction can be tested. We found that the data can be quantitatively well explained by a simple kinetic threshold model that assumes an age-dependent broadening of the protective cap at the microtubule end as a result of an evolving tapered end structure; this leads to a decrease of the cap density and its stability. This analysis suggests an intuitive picture of the role of morphological changes of the protective cap for the age dependence of microtubule stability.

Binding of Lipopolysaccharide and Cholesterol-Modified Gelatin on Supported Lipid Bilayers: Effect of Bilayer Area Confinement and Bilayer Edge Tension.

Binding of amphiphilic molecules to supported lipid bilayers (SLBs) often results in lipid fibril extension from the SLBs. Previous studies proposed that amphiphiles with large and flexible hydrophilic regions trigger lipid fibril formation in SLBs by inducing membrane curvature via their hydrophilic regions. However, no experimental studies have verified this mechanism of fibril formation. In this work, we investigated the binding of lipopolysaccharide (LPS) and cholesterol-modified gelatin to SLBs using fluorescence microscopy. SLBs with restricted and unrestricted bilayer areas were employed to identify the mechanism of fibril generation. We show that the main cause of lipid fibril formation is an approximately 20% expansion in the bilayer area rather than increased membrane curvature. The data indicate that bilayer area confinement plays a critical role in morphological changes of SLBs even when bound amphiphilic molecules have a large hydrophilic domain. We also show that bilayer area change after LPS insertion is dependent on the patch shape of the SLB. When an SLB patch consists of a broad bilayer segment connected to a long thin streak, bilayer area expansion mainly occurs within the bilayer streak. The results indicate that LPS insertion causes net lipid flow from the broad bilayer region to the streak area. The differential increase in area is explained by the instability of planar bilayer streaks that originate from the large energetic contribution of line tension arising along the bilayer edge.

Regulation of glutamate transporter 1 via BDNF-TrkB signaling plays a role in the anti-apoptotic and antidepressant effects of ketamine in chronic unpredictable stress model of depression.

Growing evidence suggests that downregulated clearance of glutamate and signaling pathways involving brain-derived neurotrophic factor (BDNF) and its receptor TrkB play a role in morphological changes in the hippocampus of depressed patients. The N-methyl-D-aspartate (NMDA) receptor antagonist ketamine is the most attractive antidepressant, although precise mechanisms are unknown. In this study, we examined whether hippocampal BDNF-TrkB signaling underlies the antidepressant effects of ketamine via upregulating glutamate transporter 1 (GLT-1) in rats, subjected to the chronic unpredictable stress (CUS) for 42 days. The rats received a single injection of ketamine (10 mg/kg, i.p.) and/or a TrkB inhibitor, K252a (1 μl, 2 mM, intracerebroventicular (i.c.v.)) on day 43. Behavioral tests and brain sample collection were evaluated 24 h later. The CUS-exposed rats exhibited depression- and anxiety-like behaviors; decreased number of glial fibrillary acidic protein (GFAP)-positive (but not NeuN-positive) cells in the dentate gyrus (DG), CA1, and CA3 areas; increased number of cleaved caspase-3-positive astrocytes; reduced spine density; lower ratio of Bcl2 to Bax; and decreased levels of BDNF, phosphorylated cAMP response element binging protein (CREB), GLT-1, and postsynaptic density 95 (PSD95) proteins in the hippocampus. Ketamine alleviated the CUS-induced abnormalities. The effects of ketamine were antagonized by pretreatment with K252a. Our findings suggest that regulation of GLT-1 on astrocytes, responsible for 90 % of glutamate reuptake from the synapse, through BDNF-TrkB signaling is involved in mediation of the therapeutic effects of ketamine on behavioral abnormalities and morphological changes in the hippocampus of the CUS-exposed rats.

Precipitate Rafting in a Polycrystalline Superalloy During Compression Creep

Rafting is an industrially and scientifically important phenomenon for precipitate-strengthened alloys utilized at high temperatures. Although this phenomenon is observed in polycrystalline alloys as well, the literature lacks scientific work on rafting in polycrystals. Scientific work is usually conducted on single-crystal superalloys. Being one of the many polycrystalline nickel-base superalloys, IN738LC has a good high-temperature strength and hot corrosion resistance. Coherency strains between the FCC gamma matrix (γ)- and L12 gamma prime (γ′)-precipitate phase particles mainly provide the high-temperature strength in IN738LC. Conical IN738LC specimens have been aged under compression for various times [24, 192, 480, and 960 hours at 1223 K (950 °C) and 12, 24, 192, and 480 hours at 1323 K (1050 °C)] in order to observe the morphological evolution of the γ′ precipitate microstructure. Dislocations play a determining role in morphological changes. Fingerprints of matrix dislocations in the form of indentations on γ′ precipitates have been identified by scanning electron microscope. Precipitate morphology has become more complex through dissolution/merging as temperature, aging time, and stress have increased. The precipitate morphology has evolved toward rafting at appropriate strain, temperature, and time. Localized slip bands have marked the beginning of rafting. The rafts have been observed at around a 45 deg angle away from the load direction. For higher stress positions, there is a trend toward N-type rafting which is expected of a positive misfit alloy under compression. Rafts eventually have collapsed due to severe creep deformation.