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1.
IEEE Trans Vis Comput Graph ; 28(4): 1917-1929, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32946396

RESUMO

Blazars are celestial bodies of high interest to astronomers. In particular, through the analysis of photometric and polarimetric observations of blazars, astronomers aim to understand the physics of the blazar's relativistic jet. However, it is challenging to recognize correlations and time variations of the observed polarization, intensity, and color of the emitted light. In our prior study, we proposed TimeTubes to visualize a blazar dataset as a 3D volumetric tube. In this paper, we build primarily on the TimeTubes representation of blazar datasets to present a new visual analytics environment named TimeTubesX, into which we have integrated sophisticated feature and pattern detection techniques for effective location of observable and recurring time variation patterns in long-term, multi-dimensional datasets. Automatic feature extraction detects time intervals corresponding to well-known blazar behaviors. Dynamic visual querying allows users to search long-term observations for time intervals similar to a time interval of interest (query-by-example) or a sketch of temporal patterns (query-by-sketch). Users are also allowed to build up another visual query guided by the time interval of interest found in the previous process and refine the results. We demonstrate how TimeTubesX has been used successfully by domain experts for the detailed analysis of blazar datasets and report on the results.

2.
Cryobiology ; 70(2): 122-35, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25645578

RESUMO

Freezing of nerve cells forming a neuronal network has largely been neglected, despite the fact that the cryopreservation of nerve cells benefits the study of cells in the areas of medicine and poison screening. Freezing of nerve cells is also attractive for studying cell morphology because of the characteristic long, thread-like neurites extending from the cell body. In the present study, freezing of neuron-like cells adhering to the substrate (differentiated PC12 cells), in physiological saline, was investigated in order to understand the fundamental freezing and thawing characteristics of nerve cells with neurites. The microscopic freezing behavior of cells under different cooling rates was observed. Next, the post-thaw morphological changes in the cells, including the cytoskeleton, were investigated and post-thaw cell viability was evaluated by dye exclusion using propidium iodide. Two categories of morphological changes, beading and shortening of the neurites, were found and quantified. Also, the morphological changes of neurites due to osmotic stress from sodium chloride were studied to gain a better understanding of causation. The results showed that morphological changes and cell death were promoted with a decrease in end temperature during freezing.


Assuntos
Criopreservação/métodos , Congelamento/efeitos adversos , Neuritos/fisiologia , Neurônios/fisiologia , Pressão Osmótica/fisiologia , Animais , Morte Celular , Diferenciação Celular , Linhagem Celular Tumoral , Sobrevivência Celular/fisiologia , Cristalização , Citoesqueleto/fisiologia , Propídio , Ratos , Cloreto de Sódio
3.
J Neurosci Res ; 88(3): 542-51, 2010 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-19774667

RESUMO

Cell replacement therapy holds great promise as a means of treating neurological disorders, including Parkinson's disease. However, one of the major obstacles to the success of this treatment is the low survival rate of grafted cells, which probably results from mechanical damage, acute inflammation, and immunological rejection. To overcome this problem, we investigated the effect of different types of extracellular matrix (ECM) on the survival and differentiation of embryonic stem (ES) cell-derived neural precursor cells (NPCs). We tested materials from natural sources, including collagen, ornithine/laminin, and growth factor-reduced Matrigel (gfrMG), as well as the synthetic biomaterial PuraMatrix, which consists of self-assembling polypeptides. GfrMG efficiently supported cell survival, migration, and neurite outgrowth in vitro and promoted proliferation of grafted cells in vivo, resulting in larger graft volume and an increase in the number of TH-positive dopaminergic neurons in the graft. GfrMG did not induce dopaminergic differentiation directly; rather, it reduced the invasion of pan-leukocytic CD45-positive cells into the graft. Insofar as the inflammatory or immune response in the host brain inhibits neuronal differentiation of grafted NPCs, gfrMG may increase the number of TH-positive cells by suppressing this effect. Thus, gfrMG appears to provide a suitable scaffold that supports survival and differentiation of NPCs. However, because it is derived from mouse sarcomas, a human-derived matrix or synthetic biomaterial must be developed for clinical applications.


Assuntos
Colágeno , Células-Tronco Embrionárias/fisiologia , Sobrevivência de Enxerto/fisiologia , Laminina , Neurogênese/fisiologia , Neurônios/fisiologia , Proteoglicanas , Animais , Encéfalo/fisiologia , Encéfalo/cirurgia , Linhagem Celular , Movimento Celular , Proliferação de Células , Sobrevivência Celular/fisiologia , Dopamina/metabolismo , Combinação de Medicamentos , Células-Tronco Embrionárias/citologia , Células-Tronco Embrionárias/transplante , Matriz Extracelular/fisiologia , Peptídeos e Proteínas de Sinalização Intercelular , Antígenos Comuns de Leucócito/metabolismo , Leucócitos/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Neuritos/fisiologia , Neurônios/transplante , Transplante de Células-Tronco , Tirosina 3-Mono-Oxigenase/metabolismo
4.
Chirality ; 17(4): 218-32, 2005 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-15830406

RESUMO

Enantiopure phthalides 2 and 5-8 were synthesized via enantioresolution of the corresponding alcohols with a chiral auxiliary of camphorsultam dichlorophthalic acid, (1S,2R,4R)-(-)-CSDP acid 3, followed by solvolysis with KOH in MeOH and the catalytic oxidation of chiral glycols with iridium complex 28. The absolute configurations of phthalides 2 and 5-8 were determined by applying the (1)H-NMR anisotropy method of MalphaNP acid (4), 2-methoxy-2-(1-naphthyl)propionic acid, to the chiral synthetic precursory alcohols. In the case of 3-phenylphthalide (R)-(-)-7, the absolute configuration determined by the (1)H-NMR anisotropy method using MalphaNP acid 4 agreed with that by the X-ray crystallographic method. By applying these methods, 3-butylphthalide (S)-(-)-2, a fragrance component of essential oil of celery, has been synthesized in an enantiopure form, and its absolute configuration was unambiguously determined.


Assuntos
Apium/química , Benzofuranos/química , Benzofuranos/síntese química , Óleos Voláteis/química , Perfumes/química , Óleos de Plantas/química , Álcoois/síntese química , Álcoois/química , Cromatografia Líquida de Alta Pressão , Ésteres , Estrutura Molecular , Sílica Gel , Dióxido de Silício , Análise Espectral , Estereoisomerismo
5.
Nature ; 423(6942): 843-4, 2003 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-12815423

RESUMO

Gamma-ray bursts (GRBs) are energetic explosions that for 0.01-100 s are the brightest gamma-ray sources in the sky. Observations of the early evolution of afterglows are expected to provide clues about the nature of the bursts, but their rapid fading has hampered such studies; some recent rapid localizations of bursts have improved the situation. Here we report an early detection of the very bright afterglow of the burst of 29 March 2003 (GRB030329). Our data show that, even early in the afterglow phase, the light curve shows unexpectedly complicated structures superimposed on the fading background.

6.
Dev Growth Differ ; 34(1): 9-16, 1992 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37281561

RESUMO

In F9 mouse embryonal carcinoma cells, the specific activity of alkaline phosphatase (ALPase) increases markedly during endodermal differentiation induced by retinoic acid (RA) treatment, but the specific 5'-nucleotidase activity of a similar ecto-phosphatase increases only temporally. Polyacrylamide disc gel electrophoresis showed that F9 cells express only type I ALPase, whereas RA-treated F9 cells express both type I and type II ALPases. Type II ALPase is a minor form on day 1 of RA treatment and becomes the major form on day 4. RA-treated F9 cells also expressed mRNAs for endoderm cell-specific molecules, such as α-fetoprotein, type IV collagen and laminin B1 chain, but their expression of M2 -type pyruvate kinase mRNA of an essential non-ectoenzyme remains constant throughout endodermal differentiation. Northern blot analyses showed that type I ALPase was encoded by a liver (L)/bone (B)/kidney (K)/placenta (P)-type mRNA. The expression of L/B/K/P-type ALPase mRNA was induced in RA-treated F9 cells, but its increase preceded that of ALPase specific activity. These results suggest that the expression of L/B/K-type ALPase is regulated at the translational and/or post-translational level. The differential inhibition of ALPases by L-phenylalanine/L-homoarginine and the thermal inactivation (56°C for 60 min) inferred that type II ALPase was also an L/B/K-type isozyme.

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