Petrology and geochemistry of volcanic rocks from ODP Sites 134-827, 134-829 and 134-830

Igneous rocks recovered from Ocean Drilling Program (ODP) Leg 134 Sites 827, 829, and 830 at the toe of the forearc slope of New Hebrides Island Arc were investigated, using petrography, mineral chemistry, major and trace element, and Sr, Nd, and Pb isotopic analyses. Basaltic and andesitic clasts, together with detrital crystals of plagioclase, pyroxenes, and amphiboles embedded in sed-lithic conglomerate or volcanic siltstone and sandstone of Pleistocene age, were recovered from Sites 827 and 830. Petrological features of these lava clasts suggest a provenance from the Western Belt of New Hebrides Island Arc; igneous constituents were incorporated into breccias and sandstones, which were in turn reworked into a second generation breccia. Drilling at Site 829 recovered a variety of igneous rocks including basalts and probably comagmatic dolerites and gabbros, plus rare ultramafic rocks. Geochemical features, including Pb isotopic ratios, of the mafic rocks are intermediate between midocean ridge basalts and island arc tholeiites, and these rocks are interpreted to be backarc basin basalts. No correlates of these mafic rocks are known from Espiritu Santo and Malakula islands, nor do they occur in the Pleistocene volcanic breccias at Sites 827 and 830. However, basalts with very similar trace element and isotopic compositions have been recovered from the northern flank of North d'Entrecasteaux Ridge at Site 828. It is proposed that igneous rocks drilled at Site 829 represent material from the North d'Entrecasteaux Ridge accreted onto the over-riding Pacific Plate during collision. An original depleted mantle harzburgitic composition is inferred for a serpentinite clast recovered at 407 meters below seafloor (mbsf) in Hole 829A. Its provenance is a matter of speculation. It could have been brought up along a deep thrust fault affecting the Pacific Plate at the colliding margin, or analogous to the Site 829 basaltic lavas, it may represent material accreted from the North d'Entrecasteaux Ridge.

(Table 1) Magnetic characteristic properties of selected samples of ODP Hole 134-831B

During Ocean Drilling Program Leg 134 (Vanuatu), geological high sensitivity magnetic tools (GHMT) developed by CEA-LETI and TOTAL were used at two drill sites. GHMT combine two sensors, a proton magnetometer for total magnetic field measurements with an operational accuracy of 0.1 nanoteslas (nT), and a highly sensitive induction tool to measure the magnetic susceptibility with an operational accuracy of a few 10**-6 SI units. Hole 829A was drilled through an accretionary prism and the downhole measurements of susceptibility correlate well with other well-log physical properties. Sharp susceptibility contrasts between chalk and volcanic silt sediment provide complementary data that help define the lithostratigraphic units. At Hole 831B magnetic susceptibility and total field measurements were performed through a 700-m reef carbonate sequence of a guyot deposited on top of an andesitic volcano. The downhole magnetic susceptibility is very low and the amplitude of peak-to-peak anomalies is less than a few 10**-5 SI units. Based on the repeatability of the measurements, the accuracy of the magnetic logging measurements was demonstrated to be excellent. Total magnetic field data at Hole 831B reveal low magnetic anomalies of 0.5 to 5 nT and the measurement of a complete repeat section indicates an accuracy of 0.1 to 0.2 nT. Due to the inclination of the earth's magnetic field in this area (~-40°) and the very low magnetic susceptibility of the carbonate, the contribution of the induced magnetization to the total field measured in the hole is negligible. Unfortunately, because the core recovery was extremely poor (<5%) no detailed comparison between the core measurements and the downhole magnetic data could be made. Most samples have a diamagnetic susceptibility and very low intensity of remanent magnetization (< 10**-4 A/m), but a few samples have a stable remanent magnetization up to 0.005 A/m. These variations of the intensity of the remanent magnetization suggest a very heterogeneous distribution of the magnetization in the carbonate sequence that could explain the magnetic field anomalies measured in these weakly magnetized rocks.

Intermittent Fugu parathyroid hormone 1 (1–34) is an anabolic bone agent in young male rats and osteopenic ovariectomized rats

Human parathyroid hormone (hPTH) is currently the only treatment for osteoporosis that forms new bone. Previously we described a fish equivalent, Fugu parathyroid hormone 1 (fPth1) which has hPTH-like biological activity in vitro despite fPth1(1–34) sharing only 53% identity with hPTH(1–34). Here we demonstrate the in vivo actions of fPth1(1–34) on bone. In study 1, young male rats were injected intermittently for 30 days with fPth1 [30 μg–1000 μg/kg body weight (b.w.), (30fPth1–1000fPth1)] or hPTH [30 μg–100 μg/kg b.w. (30hPTH–100hPTH)]. In proximal tibiae at low doses, the fPth1 was positively correlated with trabecular bone volume/total volume (TbBV/TV) while hPTH increased TbBV/TV, trabecular thickness (TbTh) and trabecular number (TbN). 500fPth1 and 1000fPth1 increased TbBV/TV, TbTh, TbN, mineral apposition rate (MAR) and bone formation rate/bone surface (BFR/BS) with a concomitant decrease in osteoclast surface and number. In study 2 ovariectomized (OVX), osteopenic rats and sham operated (SHAM) rats were injected intermittently with 500 μg/kg b.w. of fPth1 (500fPth1) for 11 weeks. 500fPth1 treatment resulted in increased TbBV/TV (151%) and TbTh (96%) in the proximal tibiae due to increased bone formation as assessed by BFR/BS (490%) and MAR (131%). The effect was restoration of TbBV/TV to SHAM levels without any effect on bone resorption. 500fPth1 also increased TbBV/TV and TbTh in the vertebrae (L6) and cortical thickness in the mid-femora increasing bone strength at these sites. fPth1 was similarly effective in SHAM rats. Notwithstanding the low amino acid sequence homology with hPTH (1–34), we have clearly established the efficacy of fPth1 (1–34) as an anabolic bone agent.

The role of His-134, -147, and -150 residues in subunit assembly, cofactor binding, and catalysis of sheep liver cytosolic serine hydroxymethyltransferase

In an attempt to unravel the role of conserved histidine residues in the structure-function of sheep liver cytosolic serine hydroxymethyltransferase (SHMT), three site-specific mutants (H134N, H147N, and H150N) were constructed and expressed, H134N and H147N SHMTs had K-m values for L-serine, L-allo-threonine and beta-phenylserine similar to that of wild type enzyme, although the k(cat) values were markedly decreased, H134N SHMT was obtained in a dimeric form with only 6% of bound pyridoxal 5'-phosphate (PLP) compared with the wild type enzyme, Increasing concentrations of PLP (up to 500 mu M) enhanced the enzyme activity without changing its oligomeric structure, indicating that His-134 may be involved in dimer-dimer interactions, H147N SHMT was obtained in a tetrameric form but with very little PLP (3%) bound to it, suggesting that this residue was probably involved in cofactor binding, Unlike the wild type enzyme, the cofactor could be easily removed by dialysis from H147N SHMT, and the apoenzyme thus formed was present predominantly in the dimeric form, indicating that PLP binding is at the dimer-dimer interface, H150N SHMT was obtained in a tetrameric form with bound PLP, However, the mutant had very little enzyme activity (<2%). The k(cat)/K-m values for L-serine, L-allo-threonine and beta-phenylserine were 80-, 56-, and SS-fold less compared with wild type enzyme, Unlike the wild type enzyme, it failed to form the characteristic quinonoid intermediate and was unable to carry out the exchange of 2-S proton from glycine in the presence of H-4-folate. However, it could form an external aldimine with serine and glycine, The wild type and the mutant enzyme had similar K-d values for serine and glycine, These results suggest that His-150 may be the base that abstracts the alpha-proton of the substrate, leading to formation of the quinonoid intermediate in the reaction catalyzed by SHMT.

Sapientia, 1979, Vol. XXXIV, nº 133-134 (número completo)

Contenido: El orden humano / Octavio N. Derisi – Los primeros principios / Gustavo E. Ponferrada – La filosofía analítica actual y su terapia mediante la filosofía cristiana y tomista / Teófilo Urdánoz – Verdad y relativismo según el pensamiento de Tomás de Aquino / William R. Darós – El mundo espiritual de la persona / Octavio N. Derisi – Ordo et mysterium / Emilio Komar – La filosofía cristiana de la libertad / Abelardo Lobato – El significado de la encíclica “Aeterni Patris” de León XIII, a los cien años de su publicación / Octavio N. Derisi – Notas y comentarios -- Bibliografía

Diário da Constituinte [gravação de vídeo] : [programa n. 134]

Após muita discussão e duas reuniões das lideranças partidárias, foi aprovado na Comissão de Sistematização o projeto da nova Constituição. Fernando Henrique Cardoso (PMDB-SP) diz que houve acordo entre as lideranças para a votação do projeto formulado por Bernardo Cabral (PMDB-AM). Sandra Cavalcanti (PFL-RJ) fez críticas ao trabalho de Bernardo Cabral, mas depois desmentiu o que foi divulgado pela imprensa. Afonso Arinos (PFL-RJ) lê nota citando o desmentido e dando integral apoio ao Relator Bernardo Cabral. Gasthone Righi (PTB-SP) quer que a Comissão de Sistematização continue apreciando as emendas dos constituintes. Cronograma dos trabalhos na Assembleia Nacional Constituinte (ANC) : discussão e apresentação de emendas no dia 14 de julho; fim do prazo para apresentar emendas no dia 14 de agosto; encerramento da primeira fase de discussão em Plenário no dia 24 de Agosto ; a Comissão de Sistematização volta a discutir o projeto no dia 25 de agosto; encerramento do prazo para votação do substitutivo na Comissão de Sistematização no dia 20 de Setembro; início da votação em 1º turno no Plenário no dia 23 de setembro. Se todos os prazos forem cumpridos, a nova Constituição será promulgada ainda em 1987 e entrará em vigor no dia 1º de janeiro de 1988. Percival Muniz (PMDB-MT) incentiva a população a participar dos debates da Assembleia Constituinte.

~(134)Ba能级结构的在束γ谱学研究

利用在束γ谱学技术 ,通过 12 8Te(10 B ,1p3n) 13 4 Ba反应研究了 13 4 Ba的中、高自旋激发态 .实验中采用 9套BGO(AC)HPGe探测器进行了γ γ t符合测量 .基于γ γ符合关系、γ射线的相对强度和各向异性度的测量结果建立了 13 4 Ba的能级纲图 .比较N =78的同中子素链的负宇称能级结构的系统性 ,发现激发能位于 4 14 2keV ,Jπ 值为 11-的能级很可能是与 13 6Ce具有相似内禀结构特征的相似态