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Middle Stage (middle + stage)
Selected AbstractsMolecular dynamics of the blood,testis barrier components during murine spermatogenesisMOLECULAR REPRODUCTION & DEVELOPMENT, Issue 7 2010Masataka Chihara The blood,testis barrier (BTB) separates the seminiferous epithelium into the adluminal and basal compartments. During murine spermatogenesis, preleptotene/leptotene spermatocytes migrate from the basal to the adluminal compartment through the BTB during stages VIII,IX. In the present study, we focused on the tight junction (TJ) molecules and analyzed their spatiotemporal expression during the murine seminiferous epithelial cycle. Structural analysis revealed that the principal components of the BTB, for example, claudin-3, claudin-11, occludin, and zonula occludens-1 (ZO-1), were localized at the basal and luminal sides of the preleptotene/leptotene spermatocytes during the migration stages (VIII,IX). Although we detected claudin-11, occludin, and ZO-1 throughout spermatogenesis, claudin-3 was only detected during stages VI,IX. Quantitative PCR using dissected seminiferous tubules from three stages (Early: II,VI, Middle: VII,VIII, Late: IX,I) clarified that the mRNA levels of TJ molecules were not correlated with the histoplanimetrical protein levels during spermatogenesis. Additionally, tubulobulbar complexes, considered to be involved in the internalization of TJ, were observed at the BTB site. Furthermore, a significant reduction in the mRNA levels of genes for the degradation of occludin (Itch) and endocytic recycling (Rab13) were observed during the Late and Middle stages, respectively. Therefore, we hypothesized that the lag between mRNA and protein expression of TJ molecules may be due to posttranslational modulation, for example, tubulobulbar complexes and endocytic recycling processes. In conclusion, these findings indicate that the integrity of the BTB is maintained throughout spermatogenesis, and the stage-specific localization of claudin-3 protein plays an important role in regulating BTB permeability. Mol. Reprod. Dev. 77: 630,639, 2010. © 2010 Wiley-Liss, Inc. [source] A cooperative distance learning method based on narrow-band Internet and its evaluationELECTRONICS & COMMUNICATIONS IN JAPAN, Issue 4 2010Dilmurat Tilwaldi Abstract This paper describes the experimental evaluation of a cooperative distance learning method, which can be utilized on narrow-band Internet. In this method, students in a group learning environment perform a series of study tasks several times, then create an online report, communicating through a chat facility about a given topic. They try to gain a benefit from their study through a more cooperative attitude. The teacher gives a short lecture at the first stage, and then gives supplementary explanations after ascertaining the degree of understanding by the students at the middle stage of the study. Teaching materials are distributed to the students' PCs beforehand and the lecture can be carried out in a narrow-band environment by transmitting commands. The teacher analyzes the students' communication logs and gives advice for the next study session. This paper describes the result of an evaluation of the proposed method involving a simulated installation of the environment within the campus, which simulated a trial of cooperative distance learning in the periphery of an overseas desert environment. © 2010 Wiley Periodicals, Inc. Electron Comm Jpn, 93(4): 36,49, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecj.10139 [source] Celite-mediated linking of polyurethane block copolymers and the impact on the shape memory effectJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2010Yong-Chan Chung Abstract Celite, a porous inorganic material with enormous surface area and hydroxyl groups on the surface, was used as a cross-linker of polyurethane (PU) copolymer chains to improve its shape memory and mechanical properties. PU copolymers with different Celite contents were prepared and characterized by IR, DSC, and universal testing machine. The glass transition temperature of PU copolymers was maintained around 20°C independent of Celite content. The shape memory and mechanical properties were dependent on when Celite was added during the polymerization reaction. The reaction in which Celite was added at the middle stage of polymerization showed the best shape memory and mechanical properties. The best shape recovery of PU was found at 0.3 wt % Celite and increased to 97% even after the third cycle. Likewise, the shape retention also maintained a remarkable 86% after three cycles. The reasons underlining the high shape recovery and shape retention by adopting Celite as a cross-linker are discussed in this article. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Major muscle systems in the larval caenogastropod, Ilyanassa obsoleta, display different patterns of developmentJOURNAL OF MORPHOLOGY, Issue 10 2009Carol C.E. Evans Abstract This study describes the anatomical and developmental aspects of muscular development from the early embryo to competent larval stage in the gastropod Ilyanassa obsoleta. Staining of F-actin revealed differential spatial and temporal patterns of several muscles. In particular, two major muscles, the larval retractor and pedal retractor muscles originate independently and display distinct developmental patterns similar to observations in other gastropod species. Additionally, together with the larval retractor muscle, the accessory larval muscle developed in the embryo at the trochophore stage. Therefore, both these muscles develop prior to ontogenetic torsion. The pedal retractor muscle marked the most abundant growth in the mid veliger stage. Also during the middle stage, the metapodial retractor muscle and opercular retractor muscle grew concurrently with development of the foot. We show evidence that juvenile muscles, such as the buccal mass muscle and siphon muscle develop initially during the late veliger stage. Collectively, these findings substantiate that larval myogenesis involves a complex sequence of events that appear evolutionary conserved within the gastropods, and set the stage for future studies using this model species to address issues concerning the evolution and eventual fates of larval musculature in molluscs. J. Morphol., 2009. © 2009 Wiley-Liss, Inc. [source] Invisible Gold from the Hishikari Epithermal Gold Deposit, Japan: Implication for Gold Distribution and DepositionRESOURCE GEOLOGY, Issue 2 2005Nobutaka Shimada Abstract. The presence of invisible gold was confirmed in arsenian pyrite from the Hishikari epithermal gold deposit, Kagoshima, Japan, by means of EPMA and SIMS analyses. The relative concentration of invisible gold may be positively correlated with As contents (0.01 to 10.37 wt%) of fine-grained arsenian pyrite which commonly occurs in the auriferous quartz veins. Although arsenian pyrite occurs widely in any mineralization stage with electrum and other sulfide, sulfosalts, selenide or telluride minerals, arsenian pyrites having higher As contents accompanied by invisible gold occur dominantly in the middle stage of fine-adularia-quartz and in the late stage of coarse-quartz rather than in the early stage of columnar-adularia. [source] Subungual melanoma: Histological examination of 50 cases from early stage to bone invasionTHE JOURNAL OF DERMATOLOGY, Issue 11 2008Miki IZUMI ABSTRACT Subungual melanoma is a rare form of malignant melanoma. It is extremely difficult to differentiate it histologically from benign melanonychia striata or melanocytic nevus, especially in the early stage. We divided 50 cases of subungual melanoma into four groups according to clinical progress, and examined their histological findings in each respective stage. In the early stage (19 cases), atypical melanocytes were polygonal showing slight nuclear atypia with no mitoses at all. In six out of 19 cases (31.6%), the atypical melanocytes proliferated more in the hyponychium than in the nail matrix, and only very few in the nail bed. Periungual pigmentation (Hutchinson's sign) appeared from the early stage in almost all cases. With stage progression (middle stage, 13 cases; progressive stage, 13 cases; and bone invasive stage, five cases) the number of atypical melanocytes and their degree of nuclear atypia increased, and the ascent of atypical melanocytes and pagetoid spread became conspicuous. Mitoses became apparent only from the progressive stage. From these observations, we would like to propose three new pathological clues of early stage subungual melanoma: (i) "skip lesion", proliferation of the tumor cells are more prominent in the hyponychium than in the nail bed or nail matrix; (ii) histological confirmation of Hutchinson's sign; and (iii) epithelial thickening and/or compact arrangement of the elongated basal cells. [source] Diagenesis and Their Succession of Gas-bearing and Non-gas-bearing Reservoirs in the Sulige Gas Field of Ordos Basin, ChinaACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 6 2009ZHU Xiaomin Abstract: Comparisons have been made among lithology, diagenesis, and reservoir characteristics of gas-bearing and non-gas-bearing ones in the Sulige gas field of the Ordos Basin based on the laboratory analysis of thin sections, scanning electron microscope, and liquid inclusion of the reservoirs. The reservoirs of the Sulige gas field are now in the middle stage of diagenesis and have undergone compaction, cementation and dissolution. The secondary pore of the reservoir originated from the dissolution of the feldspar and tuff because of the organic acid action from the source rocks during the diagenetic middle stage. Gas-bearing reservoirs are common in soluble pore diagenetic facies of coarse detritus quartzose sandstone, whereas non-gas-bearing ones are common in tense compaction diagenetic facies of mud-bearing medium-fine detritus quartzose sandstone and residual intergranular pore diagenetic facies of mud-bearing medium-coarse detritus quartzose sandstone. The secondary pore is developed in gas-bearing reservoirs of the Sulige gas-field as the medium-coarse grain reservoirs formed in a powerful sedimentary environment and experienced strong dissolution. However, the sediments of fine grain size form the non-gas-bearing reservoirs because of less residual primary pore and secondary pore. [source] Projected population-level effects of thiobencarb exposure on the mysid, Americamysis bahia, and extinction probability in a concentration-decay exposure systemENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 3 2005Sandy Raimondo Abstract Population-level effects of the mysid, Americamysis bahia, exposed to varying thiobencarb concentrations were estimated using stage-structured matrix models. A deterministic density-independent matrix model estimated the decrease in population growth rate (,) with increasing thiobencarb concentration. An elasticity analysis determined that survival of middle stages provided the largest contribution to ,. Decomposing the effects of , in terms of changes in the matrix components determined that reduced reproduction had a large influence on population dynamics at lower thiobencarb concentrations, whereas reduced survivorship had the largest impact on populations at higher concentrations. A simulation model of a concentration-decay system was developed to demonstrate the importance of integrating chemical half-life and management practices in determining population viability. In this model, mysids were originally exposed to a high thiobencarb concentration (300 ,g/L) that decayed an order of magnitude in the number of mysid generations corresponding to thiobencarb half-life values under three different exposure regimes. Environmental stochasticity was added to the model to estimate the cumulative extinction probability of mysids exposed to fluctuating concentrations of thiobencarb in random environments. The cumulative extinction probability increased with thiobencarb half-life, stochasticity, and concentration present at the time of a new exposure. The model demonstrated the expansion of population projection models in determining the ecological impact of a population exposed to pesticides. [source] Hypoxia potentiates transforming growth factor-, expression of hepatocyte during the cirrhotic condition in rat liverLIVER INTERNATIONAL, Issue 6 2004Won-II Jeong Abstract: Background/Aims: Many studies have reported that hypoxia might be associated with angiogenesis and fibrogenesis, and the level of transforming growth factor-,1 (TGF-,1) was increased in fibrotic liver and maximal at cirrhosis. Therefore, we examined the expression of TGF-,1, phosphorylated-Smad2/3 (p-Smad2/3) of the TGF-, immediate down stream signaling system and hypoxic status during hepatic fibrogenesis. Methods: Fibrosis of rats was induced by carbon tetrachloride. Collagens were detected with Azan stain. Immunohistochemistry and immunoblotting was used. Results: TGF-,1 was mainly produced by hypoxic hepatocytes at cirrhosis although myofibroblasts (MFBs) and macrophages producing TGF-,1 were decreased. Moreover, distribution of p-Smad2/3 in hepatocytes was consistent with those of hypoxic hepatocytes regardless of MFBs. Furthermore, in recovery, most MFBs disappeared, whereas positive reactions of p-Smad2/3 still existed in the hepatocytes of hypoxic areas. Therefore, TGF-,1 expression in hepatocytes might have been associated with hypoxia. Conclusions: We put forward the hypothesis that TGF-,1 is mainly produced by MFBs and macrophages at early and middle stages of fibrotic processes, but it is predominantly released by hypoxic hepatocytes in the last fibrotic stage or cirrhosis. [source] Activities of digestive enzymes during embryonic development in the crayfish Procambarus clarkii (Decapoda)AQUACULTURE RESEARCH, Issue 12 2009Ying Dai Abstract The red swamp crayfish, Procambarus clarkii (Girard), has become an important freshwater species for Chinese inland aquaculture because of its high commercial value and consumer demand. The aim of this study was to gather information about the activity of digestive enzymes at different embryonic stages of P. clarkii in order to increase our knowledge about digestive physiology and to guide technology for maternal culture so as to improve the hatching rate. Embryonic developmental stages were divided into six stages: I, fertilized egg; II, cleavage and blastula; III, gastrula; IV, egg nauplius; V, eye pigment forming; and VI, prepared for hatching. Pepsin-specific activity decreased significantly from stage I to stage IV. Although it increased at stage V, the activity level declined again before hatching. Both trypsin- and amylase-specific activity levels dramatically increased in the middle stages of embryogenesis, whereas at the other embryonic stages the activities of these two digestive enzymes were much lower. Lipase-specific activity exhibited a low level during all embryonic stages. The pattern of digestive enzyme activity was related to organogenesis and the utilization of yolk proteins at different embryonic stages. [source] Crystallographic studies of a novel DNA-binding domain from the yeast transcriptional activator Ndt80ACTA CRYSTALLOGRAPHICA SECTION D, Issue 12 2002Sherwin P. Montano The Ndt80 protein is a transcriptional activator that plays a key role in the progression of the meiotic divisions in the yeast Saccharomyces cerevisiae. Ndt80 is strongly induced during the middle stages of the sporulation pathway and binds specifically to a promoter element called the MSE to activate transcription of genes required for the meiotic divisions. Here, the preliminary structural and functional studies to characterize the DNA-binding activity of this protein are reported. Through deletion analysis and limited proteolysis studies of Ndt80, a novel 32,kDa DNA-binding domain that is sufficient for DNA-binding in vitro has been defined. Crystals of the DNA-binding domain of Ndt80 in two distinct lattices have been obtained, for which diffraction data extend to 2.3,Å resolution. [source] Tracing of intracellular zinc(II) fluorescence flux to monitor cell apoptosis by using FluoZin-3AMCELL BIOCHEMISTRY AND FUNCTION, Issue 7 2009Yi-Ming Li Abstract Changes in the free zinc(II) concentration are closely related to cell proliferation and apoptosis, especially during the early apoptotic process. In the present paper, we demonstrated that zinc(II) probe FluoZin-3AM owns sensitive properties to distinguish different stages of apoptotic cell (induced by an anticancer agent, etoposide) according to trace intracellular zinc(II) fluorescence flux. When apoptosis in HeLa or K562 cells was artificially induced, FluoZin-3AM selectively and strongly stained apoptotic cells only at early and middle stages, which was attributed to significantly increased free zinc(II) flux during these stages. This conclusion was further verified by comparing it with the conventional apoptosis detector probe Annexin-V-FITC and PI. Furthermore, FluoZin-3AM was found cell permeable to detect the intracellular zinc(II) fluorescence enhancement to threefolds within 120,s with low cytotoxicity when zinc(II) was incorporated into the cell by zinc(II) ionophore pyrithione. All the above implied that monitoring intracellular zinc fluorescence flux was an effective method to distinguish cell apoptosis from necrosis, and FluoZin-3AM was found to be a suitable probe acting alone to fulfill the work. Copyright © 2009 John Wiley & Sons, Ltd. [source] Functional Properties of Glycated Soy 11S GlycininJOURNAL OF FOOD SCIENCE, Issue 4 2005Allaoua Achouri ABSTRACT: 11S-rich glycinin fraction was extracted from defatted soy flakes and glycated using glucose (at a 1:44 molar ratio of protein to sugar) through the Maillard reaction. The glycation was done at 50°C and 65% relative humidity for varying incubation periods (6, 16, 24, and 48 h). Fluorescamine and trinitrobenzenesulfonic acid (TNBS) methods both revealed a gradual increase in % glycation from 34.8% to 39.6%, 42.6%, and 46.5%, as samples were glycated from 6 to 48 h. Functional studies of the glycated 11S-rich glycinin fraction showed an initial increase in solubility during the early stages of glycation and a decrease as glycation progressed beyond 24 h. Glycation in the 1st hour of incubation also decreased protein surface hydrophobicity and fat absorption capacity (FAC). This was mainly attributed to an increase in the net negative charge induced by the introduction of the sugar moiety. As the Maillard reaction progressed (24 h and 48 h of incubation), an increase in FAC and surface hydrophobicity was observed. The results further showed an increase in foaming properties and emulsifying activity of the 11S-rich glycinin fraction with glycation (compared with control), especially at the early and middles stages of the Maillard reaction. [source] | |||||||||||||||||||