Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 184
Filtrar
1.
Science ; 379(6634): eabn8671, 2023 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-36137011

RESUMO

Samples of the carbonaceous asteroid Ryugu were brought to Earth by the Hayabusa2 spacecraft. We analyzed 17 Ryugu samples measuring 1 to 8 millimeters. Carbon dioxide-bearing water inclusions are present within a pyrrhotite crystal, indicating that Ryugu's parent asteroid formed in the outer Solar System. The samples contain low abundances of materials that formed at high temperatures, such as chondrules and calcium- and aluminum-rich inclusions. The samples are rich in phyllosilicates and carbonates, which formed through aqueous alteration reactions at low temperature, high pH, and water/rock ratios of <1 (by mass). Less altered fragments contain olivine, pyroxene, amorphous silicates, calcite, and phosphide. Numerical simulations, based on the mineralogical and physical properties of the samples, indicate that Ryugu's parent body formed ~2 million years after the beginning of Solar System formation.

2.
Science ; 375(6584): 1011-1016, 2022 03 04.
Artigo em Inglês | MEDLINE | ID: mdl-35143255

RESUMO

The Hayabusa2 spacecraft investigated the C-type (carbonaceous) asteroid (162173) Ryugu. The mission performed two landing operations to collect samples of surface and subsurface material, the latter exposed by an artificial impact. We present images of the second touchdown site, finding that ejecta from the impact crater was present at the sample location. Surface pebbles at both landing sites show morphological variations ranging from rugged to smooth, similar to Ryugu's boulders, and shapes from quasi-spherical to flattened. The samples were returned to Earth on 6 December 2020. We describe the morphology of >5 grams of returned pebbles and sand. Their diverse color, shape, and structure are consistent with the observed materials of Ryugu; we conclude that they are a representative sample of the asteroid.

3.
Phys Rev Lett ; 124(20): 207005, 2020 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-32501068

RESUMO

The discovery of charge-density-wave-related effects in the resonant inelastic x-ray scattering spectra of cuprates holds the tantalizing promise of clarifying the interactions that stabilize the electronic order. Here, we report a comprehensive resonant inelastic x-ray scattering study of La_{2-x}Sr_{x}CuO_{4} finding that charge-density wave effects persist up to a remarkably high doping level of x=0.21 before disappearing at x=0.25. The inelastic excitation spectra remain essentially unchanged with doping despite crossing a topological transition in the Fermi surface. This indicates that the spectra contain little or no direct coupling to electronic excitations near the Fermi surface, rather they are dominated by the resonant cross section for phonons and charge-density-wave-induced phonon softening. We interpret our results in terms of a charge-density wave that is generated by strong correlations and a phonon response that is driven by the charge-density-wave-induced modification of the lattice.

4.
Bone Joint J ; 98-B(12): 1704-1710, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27909135

RESUMO

AIMS: To determine the normal values and usefulness of the C1/4 space available for spinal cord (SAC) ratio and C1 inclination angle, which are new radiological parameters for assessing atlantoaxial instability in children with Down syndrome. PATIENTS AND METHODS: We recruited 272 children with Down syndrome (including 14 who underwent surgical treatment), and 141 children in the control group. All were aged between two and 11 years. The C1/4 SAC ratio, C1 inclination angle, atlas-dens interval (ADI), and SAC were measured in those with Down syndrome, and the C1/4 SAC ratio and C1 inclination angle were measured in the control group. RESULTS: The mean C1/4 SAC ratio in those requiring surgery with Down syndrome, those with Down syndrome not requiring surgery and controls were 0.63 (standard deviation (sd) 0.1), 1.15 (sd 0.13) and 1.29 (sd 0.14), respectively, and the mean C1 inclination angles were -3.1° (sd 10.7°), 15.8° (sd 7.3) and 17.2° (sd 7.3), in these three groups, respectively. The mean ADI and SAC in those with Down syndrome requiring surgery and those with Down syndrome not requiring surgery were 9.8 mm (sd 2.8) and 4.3 mm (sd 1.0), and 11.1 mm (sd 2.6) and 18.5 mm (sd 2.4), respectively. CONCLUSION: The normal values of the C1/4 SAC ratio and the C1 inclination angle were found to be about 1.2° and 15º, respectively. Cite this article: Bone Joint J 2016;98-B:1704-10.


Assuntos
Articulação Atlantoaxial/diagnóstico por imagem , Síndrome de Down/complicações , Instabilidade Articular/diagnóstico por imagem , Traumatismos da Medula Espinal/etiologia , Distribuição por Idade , Articulação Atlantoaxial/cirurgia , Estudos de Casos e Controles , Vértebras Cervicais/diagnóstico por imagem , Vértebras Cervicais/patologia , Criança , Pré-Escolar , Síndrome de Down/patologia , Feminino , Humanos , Instabilidade Articular/etiologia , Instabilidade Articular/patologia , Instabilidade Articular/cirurgia , Masculino , Radiografia , Valores de Referência , Distribuição por Sexo
5.
Clin Genet ; 90(6): 526-535, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-27434533

RESUMO

Joubert syndrome (JS) is rare recessive disorders characterized by the combination of hypoplasia/aplasia of the cerebellar vermis, thickened and elongated superior cerebellar peduncles, and a deep interpeduncular fossa which is defined by neuroimaging and is termed the 'molar tooth sign'. JS is genetically highly heterogeneous, with at least 29 disease genes being involved. To further understand the genetic causes of JS, we performed whole-exome sequencing in 24 newly recruited JS families. Together with six previously reported families, we identified causative mutations in 25 out of 30 (24 + 6) families (83.3%). We identified eight mutated genes in 27 (21 + 6) Japanese families, TMEM67 (7/27, 25.9%) and CEP290 (6/27, 22.2%) were the most commonly mutated. Interestingly, 9 of 12 CEP290 disease alleles were c.6012-12T>A (75.0%), an allele that has not been reported in non-Japanese populations. Therefore c.6012-12T>A is a common allele in the Japanese population. Importantly, one Japanese and one Omani families carried compound biallelic mutations in two distinct genes (TMEM67/RPGRIP1L and TMEM138/BBS1, respectively). BBS1 is the causative gene in Bardet-Biedl syndrome. These concomitant mutations led to severe and/or complex clinical features in the patients, suggesting combined effects of different mutant genes.


Assuntos
Anormalidades Múltiplas/genética , Proteínas Adaptadoras de Transdução de Sinal/genética , Antígenos de Neoplasias/genética , Cerebelo/anormalidades , Anormalidades do Olho/genética , Doenças Renais Císticas/genética , Proteínas de Membrana/genética , Proteínas Associadas aos Microtúbulos/genética , Proteínas de Neoplasias/genética , Retina/anormalidades , Anormalidades Múltiplas/diagnóstico por imagem , Anormalidades Múltiplas/epidemiologia , Anormalidades Múltiplas/fisiopatologia , Alelos , Proteínas de Ciclo Celular , Cerebelo/diagnóstico por imagem , Cerebelo/fisiopatologia , Proteínas do Citoesqueleto , Anormalidades do Olho/diagnóstico por imagem , Anormalidades do Olho/epidemiologia , Anormalidades do Olho/fisiopatologia , Feminino , Heterogeneidade Genética , Predisposição Genética para Doença , Humanos , Japão/epidemiologia , Doenças Renais Císticas/diagnóstico por imagem , Doenças Renais Císticas/epidemiologia , Doenças Renais Císticas/fisiopatologia , Masculino , Mutação , Omã/epidemiologia , Linhagem , Retina/diagnóstico por imagem , Retina/fisiopatologia
6.
Radiat Prot Dosimetry ; 167(1-3): 358-64, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25982790

RESUMO

Activities were introduced in Kashiwa city in the Tokyo metropolitan area to correspond to the elevated environmental radiation level after the disaster of the Fukushima Daiichi nuclear power plant. These were based on a strong cooperation between local governments and experts. Ambient dose rate and radioactivity of foodstuff produced inside of the city have been monitored. Representative ambient dose rates around living environments have almost already become their original levels of the pre-accident because of the decontamination activity, natural washout and effective half-lives of radioactivity. The internal annual dose due to radioactive cesium under the policy of 'Local Production for Local Consumption' is estimated as extremely low comparing the variation range due to natural radioactivity. Systematic survey around a retention basin has been started. All of these latest monitoring data would be one of the core information for the policy making as well as a cost-benefit discussion and risk communication.


Assuntos
Comportamento Cooperativo , Contaminação Radioativa de Alimentos/análise , Acidente Nuclear de Fukushima , Governo Local , Proteção Radiológica/métodos , Cinza Radioativa/análise , Descontaminação/métodos , Prova Pericial/métodos , Contaminação Radioativa de Alimentos/prevenção & controle , Relações Interinstitucionais , Cinza Radioativa/prevenção & controle , Gestão da Segurança/organização & administração
7.
AJNR Am J Neuroradiol ; 34(10): 2034-8, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23681356

RESUMO

BACKGROUND AND PURPOSE: X-linked α-thalassemia/mental retardation syndrome (Mendelian Inheritance in Man, 301040) is one of the X-linked intellectual disability syndromes caused by mutations of the ATRX gene and characterized by male predominance, central hypotonic facies, severe cognitive dysfunction, hemoglobin H disease (α-thalassemia), genital and skeletal abnormalities, and autistic and peculiar behavior. More than 200 patients in the world, including >70 Japanese patients, have been diagnosed with ATR-X syndrome. MATERIALS AND METHODS: We reviewed the brain MRI and/or CT findings of 27 Japanese patients with ATR-X with ATRX mutations retrospectively. RESULTS: The findings were categorized into 5 types: 1) nonspecific brain atrophy (17/27); 2) white matter abnormalities, especially around the trigones (11/27); 3) widespread and scattered white matter abnormalities (1/27); 4) delayed myelination (4/27); and 5) severe and rapidly progressive cortical brain atrophy (1/27). CONCLUSIONS: This is the first report on a comprehensive study of brain MRI/CT findings of ATR-X syndrome. Our findings suggest that the ATRX protein seems to be involved in normal myelination. The classification will require revisions in the near future, but it will be helpful in establishing the relationship between ATRX mutation and brain development and understanding the ATRX protein function in the brain.


Assuntos
DNA Helicases/genética , Imageamento por Ressonância Magnética , Deficiência Intelectual Ligada ao Cromossomo X , Bainha de Mielina/patologia , Proteínas Nucleares/genética , Tomografia Computadorizada por Raios X , Talassemia alfa , Adolescente , Adulto , Povo Asiático , Atrofia/diagnóstico por imagem , Atrofia/genética , Atrofia/patologia , Criança , Pré-Escolar , DNA Helicases/fisiologia , Progressão da Doença , Humanos , Lactente , Leucoencefalopatias/diagnóstico por imagem , Leucoencefalopatias/genética , Leucoencefalopatias/patologia , Deficiência Intelectual Ligada ao Cromossomo X/diagnóstico por imagem , Deficiência Intelectual Ligada ao Cromossomo X/genética , Deficiência Intelectual Ligada ao Cromossomo X/patologia , Pessoa de Meia-Idade , Bainha de Mielina/fisiologia , Proteínas Nucleares/fisiologia , Estudos Retrospectivos , Proteína Nuclear Ligada ao X , Adulto Jovem , Talassemia alfa/diagnóstico por imagem , Talassemia alfa/genética , Talassemia alfa/patologia
10.
Phys Rev Lett ; 103(7): 077203, 2009 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-19792681

RESUMO

We present the first application of pulsed high magnetic fields up to 30 T for neutron diffraction experiments. As the first study, field variations of a couple of magnetic Bragg reflections have successfully been measured in the frustrated antiferromagnet TbB4. The results show that the conventional models fail, and a model, which is a mixture of the XY- and the Ising-type moments, matches for the half-magnetization state. We deduce an interaction that stabilizes an orthogonal moment arrangement as an origin of the unusual magnetization plateaus. Our results demonstrate the powerfulness of the present pulsed magnetic fields neutron diffraction system.

11.
Clin Genet ; 75(4): 384-93, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19320658

RESUMO

Congenital anomaly syndromes manifesting overgrowth are rare, and only a small number of recognized or defined conditions are known to be associated with overgrowth. Some of them are related to genomic imprinting as a genetic cause. We report a girl who showed pre- and postnatal overgrowth who was found to have a 2.3-Mb deletion of 9q22.32 involving PTCH1, the gene responsible for Gorlin syndrome (nevoid basal cell carcinoma syndrome), by array-comparative genomic hybridization analysis. Clinical re-evaluation according to the diagnostic criteria was performed after identification of the PTCH1 deletion, and the patient was then diagnosed as having Gorlin syndrome. Further delineation involved unusual features including cerebellar dysplasia, an ectopic meninx on her shoulder, and an intraorbital hemangioma. Overgrowth is not a common finding in Gorlin syndrome. We reviewed 23 patients reported to have a 9q22 deletion. Five patients, including our patient, had overgrowth and loss of the paternal allele.


Assuntos
Deleção Cromossômica , Cromossomos Humanos Par 9 , Síndrome do Nevo Basocelular/genética , Deficiências do Desenvolvimento/genética , Pai , Feminino , Impressão Genômica , Humanos , Recém-Nascido , Receptores Patched , Receptor Patched-1 , Receptores de Superfície Celular/genética
12.
AJNR Am J Neuroradiol ; 30(3): 629-34, 2009 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19112063

RESUMO

BACKGROUND AND PURPOSE: The causative gene of the common congenital malformation referred to as CHARGE syndrome is CHD7. Affected individuals often undergo head and neck imaging to assess abnormalities of the olfactory structures, hypothalamus-pituitary axis, and inner ear. We encountered a few children with severe hypoplasia of the basiocciput during a radiologic assessment of patients with CHARGE syndrome. To our knowledge, this anomaly has not been reported. Our purpose was to evaluate the incidence and severity of this anomaly in this syndrome. MATERIALS AND METHODS: Sagittal MR images of 8 patients with CHARGE syndrome were retrospectively reviewed by 2 radiologists who consensually evaluated the status of the basiocciput of the patients with CHARGE syndrome, as either normal or hypoplastic; and associated anomalies, which include basilar invagination, Chiari type I malformation, and syringomyelia, as either present or absent. The length between the basion (Ba) and the endo-sphenobasion (Es) and between the basion and the exo-sphenobasion (Xs) was measured on midsagittal MR images of the 8 patients and 70 age-matched controls. We searched for trends related to age in the length of Ba-Es and Ba-Xs of the control children by using a matched t test. RESULTS: Basioccipital hypoplasia was identified in 7 of the 8 patients with CHARGE syndrome and was severe in 6. Of those, 5 had associated basilar invagination and 1 had Chiari type I malformation with syringomyelia. CONCLUSIONS: Basioccipital hypoplasia and basilar invagination are prevalent in patients with CHARGE syndrome.


Assuntos
Anormalidades Múltiplas/patologia , Fossa Craniana Posterior/anormalidades , Osso Esfenoide/anormalidades , Anormalidades Múltiplas/epidemiologia , Anormalidades Múltiplas/genética , Adulto , Criança , Pré-Escolar , Atresia das Cóanas/epidemiologia , Atresia das Cóanas/patologia , Coloboma/epidemiologia , Coloboma/patologia , DNA Helicases/genética , Proteínas de Ligação a DNA/genética , Orelha Interna/anormalidades , Transtornos do Crescimento/patologia , Cardiopatias Congênitas/epidemiologia , Cardiopatias Congênitas/patologia , Humanos , Sistema Hipotálamo-Hipofisário/anormalidades , Incidência , Bulbo Olfatório/anormalidades , Estudos Retrospectivos , Índice de Gravidade de Doença , Síndrome
14.
Appl Microbiol Biotechnol ; 72(1): 145-154, 2006 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-16374634

RESUMO

A new actinomycete strain designated MITKK-103 was isolated from the soil of a flowerpot using a humic acid agar medium. The newly isolated strain was able to produce a large amount of actinomycin X2 even under nonoptimized growing conditions and serves as a promising source of this antibiotic. Actinomycin X2 has higher cytotoxicity toward cultured human leukemia (HL-60) cells than does actinomycin D, and it induces cell death via apoptosis. A nearly complete 16S ribosomal DNA (rDNA) sequence from the isolate was determined and found to have high identity (98.5-100%) with Streptomyces galbus, Streptomyces griseofuscus, and Streptomyces padanus, indicating that MITKK-103 belongs to the genus Streptomyces. The isolate clustered with species belonging to the S. padanus clade in a 16S-rDNA-based phylogenetic tree and showed 75% overall homology to S. padanus ATCC 25646 in DNA-DNA relatedness analysis. Although the growth of the isolate was somewhat different from the three species mentioned, the strain MITKK-103 most closely resembles S. padanus on the basis of the morphological and phenotypic characteristics, phylogenetic analysis, and genotypic data. As such, this is the first report of a strain of S. padanus capable of producing actinomycins.


Assuntos
Dactinomicina/análogos & derivados , Microbiologia do Solo , Streptomyces/metabolismo , Técnicas de Tipagem Bacteriana , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Dactinomicina/biossíntese , Dactinomicina/toxicidade , Células HL-60 , Humanos , Microscopia Eletrônica de Varredura , Dados de Sequência Molecular , Hibridização de Ácido Nucleico , Filogenia , Pigmentos Biológicos/biossíntese , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Homologia de Sequência do Ácido Nucleico , Streptomyces/classificação , Streptomyces/isolamento & purificação , Streptomyces/ultraestrutura
16.
Acta Paediatr ; 92(9): 1039-42, 2003 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-14599066

RESUMO

AIM: To determine the natural growth pattern of Japanese children with Down's syndrome. METHODS: Longitudinal height data of 85 patients (43 males, 42 females) from birth to final height were analyzed. Based on these data, semi-longitudinal standard growth curves and height velocity curves for Down's syndrome were drawn. RESULTS: The means +/- SD of final height of males and females with Down's syndrome were 153.2 +/- 5.6 and 141.9 +/- 4.2 cm, respectively. They were -3.0 SD and -2.8 SD for Japanese standards. Mean peak height velocities were 8.9 and 7.5 cm y(-1), and the ages at peak height velocity were 11.6 and 10.2 y for males and females, respectively. CONCLUSION: The mean height of patients with Down's syndrome was around -2 SD for normal children before puberty. Their pubertal growth spurt starts about 1 y earlier and their peak height velocity was about 1.3-1.4 cm shorter than for normal children.


Assuntos
Estatura , Síndrome de Down/fisiopatologia , Povo Asiático , Criança , Síndrome de Down/etnologia , Feminino , Humanos , Japão , Masculino
18.
J Pediatr ; 139(6): 892-5, 2001 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11743521

RESUMO

We report 4 female patients and 1 male patient with a 22q11.2 deletion and Graves' disease diagnosed at age 27 months, 7, 10, 17, and 16 years, respectively. The clinical presentations were typical for hyperthyroidism, but 1 female infant had seizures in addition to symptoms of hyperthyroidism. All patients had elevated serum levels of thyroid hormones in association with suppressed thyroid-stimulating hormone levels. From these observations, we suggest that Graves' disease may be a part of the clinical spectrum associated with the 22q11.2 deletion syndrome.


Assuntos
Deleção Cromossômica , Cromossomos Humanos Par 22/genética , Doença de Graves/genética , Adolescente , Adulto , Pré-Escolar , Feminino , Doença de Graves/sangue , Humanos , Masculino , Hormônios Tireóideos/sangue , Hormônios Tireóideos/genética , Tireotropina/sangue , Tireotropina/genética
20.
Jpn J Cancer Res ; 92(11): 1235-41, 2001 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11714449

RESUMO

SNF4435C and D, novel immunosuppressants produced by a strain of Streptomyces spectabilis, were examined for their reversing effects in vitro on various multidrug-resistant (MDR) tumor cells overexpressing P-glycoprotein. These two compounds in the range of 3-10 microM completely reversed the resistance of MDR variant cells, mouse leukemia P388 cells [vincristine (VCR)-resistant P388/VCR and adriamycin (ADM)-resistant P388/ADM], human myelogenous leukemia K562 cells (VCR-resistant K562/VCR and ADM-resistant K562/ADM) and human ovarian cancer A2780 cells (ADM-resistant AD(10)), against VCR. Both compounds moderately potentiated the sensitivity of the MDR cells to ADM but the reversal was not complete. SNF4435C and D significantly increased the intracellular accumulation of VCR in AD(10) cells as potently as verapamil, cyclosporin A (CysA) and FK506, whereas the compounds exerted no effect on the accumulation of VCR in the drug-sensitive parent cells. Moreover, SNF4435C improved the chemotherapeutic efficacy of VCR in the treatment of P388/VCR-bearing mice. When 10 mg/kg SNF4435C was administered intraperitoneally to the mice concurrently with 0.2 mg/kg VCR for every 5 days, a treated/control (T/C) value of 143% was obtained. These results suggest that the compounds are useful candidates or tools for MDR modification in cancer chemotherapy.


Assuntos
Resistência a Múltiplos Medicamentos , Resistencia a Medicamentos Antineoplásicos , Nitrocompostos/farmacologia , Pironas/farmacologia , Animais , Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Divisão Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Doxorrubicina/farmacologia , Doxorrubicina/uso terapêutico , Sinergismo Farmacológico , Feminino , Humanos , Concentração Inibidora 50 , Camundongos , Mitolactol/farmacologia , Mitolactol/uso terapêutico , Mitomicinas/farmacologia , Mitomicinas/uso terapêutico , Transplante de Neoplasias , Neoplasias/tratamento farmacológico , Células Tumorais Cultivadas , Vincristina/farmacologia , Vincristina/uso terapêutico
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...