147 research outputs found
The Lotthers: Forgotten Printers of the Reformation
The name Lotther is so similar to that of our Reformer that it must arouse the curiosity of the reader when he finds this name recorded in Luther\u27s correspondence. Yet most Luther biographies do not even mention this name, and those that do pass it over lightly. Thus the family which has rendered outstanding service to the cause of the Reformation is today all but forgotten
Lotharmeyerite, Ca(Zn,Mn)2(AsO4)2(H2O,OH)2
Lotharmeyerite, calcium bis(zinc/manganese) bis(arsenate) bis(hydroxide/hydrate), Ca(Zn,Mn3+)2(AsO4)2(H2O,OH)2, is a member of the natrochalcite group of minerals, which are characterized by the general formula AM
2(XO4)2(H2O,OH)2, where A may be occupied by Pb2+, Ca2+, Na+, and Bi3+, M by Fe3+, Mn3+, Cu2+, Zn2+, Co2+, Ni2+, Al3+, and Mg2+, and X by PV, AsV, VV, and SVI. The minerals in the group display either monoclinic or triclinic symmetry, depending on the ordering of chemical components in the M site. Based on single-crystal X-ray diffraction data of a sample from the type locality, Mapimi, Durango, Mexico, this study presents the first structure determination of lotharmeyerite. Lotharmeyerite is isostructural with natrochalcite and tsumcorite. The structure is composed of rutile-type chains of edge-shared MO6 octahedra (site symmetry ) extending along [010], which are interconnected by XO4 tetrahedra (site symmetry 2) and hydrogen bonds to form [M
2(XO4)2(OH,H2O)2] sheets parallel to (001). These sheets are linked by the larger A cations (site symmetry 2/m), as well as by hydrogen bonds. Bond-valence sums for the M cation, calculated with the parameters for Mn3+ and Mn2+ are 2.72 and 2.94 v.u., respectively, consistent with the occupation of the M site by Mn3+. Two distinct hydrogen bonds are present, one with O⋯O = 2.610 (4) Å and the other O⋯O = 2.595 (3) Å. One of the H-atom positions is disordered over two sites with 50% occupancy, in agreement with observations for other natrochalcite-type minerals, such as natrochalcite and tsumcorite
Accelerated discovery of two crystal structure types in a complex inorganic phase field
The discovery of new materials is hampered by the lack of efficient approaches to the exploration of both the large number of possible elemental compositions for such materials, and of the candidate structures at each composition1. For example, the discovery of inorganic extended solid structures has relied on knowledge of crystal chemistry coupled with time-consuming materials synthesis with systematically varied elemental ratios2,3. Computational methods have been developed to guide synthesis by predicting structures at specific compositions4,5,6 and predicting compositions for known crystal structures7,8, with notable successes9,10. However, the challenge of finding qualitatively new, experimentally realizable compounds, with crystal structures where the unit cell and the atom positions within it differ from known structures, remains for compositionally complex systems. Many valuable properties arise from substitution into known crystal structures, but materials discovery using this approach alone risks both missing best-in-class performance and attempting design with incomplete knowledge8,11. Here we report the experimental discovery of two structure types by computational identification of the region of a complex inorganic phase field that contains them. This is achieved by computing probe structures that capture the chemical and structural diversity of the system and whose energies can be ranked against combinations of currently known materials. Subsequent experimental exploration of the lowest-energy regions of the computed phase diagram affords two materials with previously unreported crystal structures featuring unusual structural motifs. This approach will accelerate the systematic discovery of new materials in complex compositional spaces by efficiently guiding synthesis and enhancing the predictive power of the computational tools through expansion of the knowledge base underpinning them
The Interactive Effects of Ammonia and Microcystin on Life-History Traits of the Cladoceran Daphnia magna: Synergistic or Antagonistic?
The occurrence of Microcystis blooms is a worldwide concern that has caused numerous adverse effects on water quality and lake ecology. Elevated ammonia and microcystin concentrations co-occur during the degradation of Microcystis blooms and are toxic to aquatic organisms; we studied the relative and combined effects of these on the life history of the model organism Daphnia magna. Ammonia and microcystin-LR treatments were: 0, 0.366, 0.581 mg L−1 and 0, 10, 30, 100 µg L−1, respectively. Experiments followed a fully factorial design. Incubations were 14 d and recorded the following life-history traits: number of moults, time to first batch of eggs, time to first clutch, size at first batch of eggs, size at first clutch, number of clutches per female, number of offspring per clutch, and total offspring per female. Both ammonia and microcystin were detrimental to most life-history traits. Interactive effects of the toxins occurred for five traits: the time to first batch of eggs appearing in the brood pouch, time to first clutch, size at first clutch, number of clutches, and total offspring per female. The interactive effects of ammonia and microcystin appeared to be synergistic on some parameters (e.g., time to first eggs) and antagonistic on others (e.g., total offspring per female). In conclusion, the released toxins during the degradation of Microcystis blooms would result, according to our data, in substantially negative effect on D. magna
TCERG1L allelic variation is associated with cisplatin-induced hearing loss in childhood cancer, a PanCareLIFE study.
In children with cancer, the heterogeneity in ototoxicity occurrence after similar treatment suggests a role for genetic susceptibility. Using a genome-wide association study (GWAS) approach, we identified a genetic variant in TCERG1L (rs893507) to be associated with hearing loss in 390 non-cranial irradiated, cisplatin-treated children with cancer. These results were replicated in two independent, similarly treated cohorts (n = 192 and 188, respectively) (combined cohort: P = 5.3 × 10-10, OR 3.11, 95% CI 2.2-4.5). Modulating TCERG1L expression in cultured human cells revealed significantly altered cellular responses to cisplatin-induced cytokine secretion and toxicity. These results contribute to insights into the genetic and pathophysiological basis of cisplatin-induced ototoxicity
Significance of vascular endothelial growth factor in growth and peritoneal dissemination of ovarian cancer
Vascular endothelial growth factor (VEGF) is a key regulator of angiogenesis which drives endothelial cell survival, proliferation, and migration while increasing vascular permeability. Playing an important role in the physiology of normal ovaries, VEGF has also been implicated in the pathogenesis of ovarian cancer. Essentially by promoting tumor angiogenesis and enhancing vascular permeability, VEGF contributes to the development of peritoneal carcinomatosis associated with malignant ascites formation, the characteristic feature of advanced ovarian cancer at diagnosis. In both experimental and clinical studies, VEGF levels have been inversely correlated with survival. Moreover, VEGF inhibition has been shown to inhibit tumor growth and ascites production and to suppress tumor invasion and metastasis. These findings have laid the basis for the clinical evaluation of agents targeting VEGF signaling pathway in patients with ovarian cancer. In this review, we will focus on VEGF involvement in the pathophysiology of ovarian cancer and its contribution to the disease progression and dissemination
Persisitierende hochnormale Blutdruckwerte als potentieller Risikofaktor atrialer Arrhythmierezidive nach Hochfrequenzstromablation
Cornubite, Cu<sub>5</sub>(AsO<sub>4</sub>)<sub>2</sub>(OH)<sub>4</sub>, first occurrence of single crystals, mineralogical description and crystal structure
The first single crystals of the rare copper arsenate hydroxide cornubite, Cu5(AsO4)2(OH)4, have been found from a silicified barite vein at Reichenbach, Odenwald near Bensheim, Hessen, W.-Germany. Cornubite occurs as apple-green, translucent and mostly tabular crystals, up to 0.3 X 0.3 mm in size and up to 0.05 mm thick. The lustre is vitreous, streak light-green and hardness 4. The indices of refraction are between 1.8 and 1.9 and the optical angle is very large. The results of electron microprobe analysis are As2O5 32.01, CuO 58.60, SiO2 0.34, P2O5 0.25, Al2O3 0.15, Fe2O3 0.32, H2O (calculated) 5.27 weight total 96.94 weight %. The empirical formula is Cu5.03 (As1.903 P0.024 Fe0.027 Al0.020 Si0.038)2.013O8 (OH)4. X-ray single crystal diffraction studies gave triclinic symmetry, space group P1 with a = 6.121(1), b = 6.251(1), c = 6.790(1) Å, α = 92.93(1)°, β = 111.30(1)° and γ = 107.47(1)°, V = 227.09 Å3, Z = 1, Dx = 4.85 Mg/m3. The crystal structure contains sheets of edge-sharing CuO6-octahedra // (011) connected by AsO4 tetrahedra via common corners and by hydrogen bonds
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