One-Step Facile Synthesis of Cobalt Phosphides for Hydrogen Evolution Reaction Catalysts in Acidic and Alkaline Medium

Catalysts for hydrogen evolution reaction are in demand to realize the efficient conversion of hydrogen via water electrolysis. In this work, cobalt phosphides were prepared using a one-step, scalable, and direct gas-solid phosphidation of commercially available cobalt salts. It was found that the effectiveness of the phosphidation reaction was closely related to the state of cobalt precursors at the reaction temperature. For instance, a high yield of cobalt phosphides obtained from the phosphidation of cobalt(II) acetate was related to the good stability of cobalt salt at the phosphidation temperature. On the other hand, easily oxidizable salts (e.g., cobalt(II) acetylacetonate) tended to produce a low amount of cobalt phosphides and a large content of metallic cobalt. The as-synthesized cobalt phosphides were in nanostructures with large catalytic surface areas. The catalyst prepared from phosphidation of cobalt(II) acetate exhibited an improved catalytic activity as compared to its counterpart derived from phosphidation of cobalt(II) acetylacetonate, showing an overpotential of 160 and 175 mV in acidic and alkaline electrolytes, respectively. Both catalysts also displayed an enhanced long-term stability, especially in the alkaline electrolyte. This study illustrates the direct phosphidation behavior of cobalt salts, which serve as a good vantage point in realizing the large-scale synthesis of transition-metal phosphides for high-performance electrocatalysts.

[Association of low 50 g glucose screening test in pregnancy and fetal retardation]

BACKGROUND

The connection between elevated blood sugar and macrosomia is sufficiently well known and studied. The following study, however, examines whether patients with lower blood sugar values--based on the result of the 50 g-glucose screening test--delivered smaller children than patients with normal blood sugar based on the current criteria of blood sugar levels. PATIENTS RESPECTIVELY AND METHODS: In this study, all patients were included who visited our Prenatal Counseling Center between September 21, 1994 and July 31, 1996. Not included were patients with one-hour values greater or equal to 140 mg/dl. For assessing the 50 g-screening tests, percentiles were used. Based on the tables of Voigt, children below the 10th percentile were considered to be growth retarded. The student's t-test and chi-square test were employed as statistical tests.

RESULTS

Of the 1416 participating patients in the study, 868 fulfilled the aforementioned criteria. A significant statistical correlation was shown between the development of fetal retardation and nicotine consumption, weight gain, and maternal height. It was also shown that patients with a lower (< 93 mg/dl) 50 g-screening test more often delivered a retarded child than patients with a normal value (23% vs. 12%, p = 0.034). No significant connection was found between the screening test groups and the described influencing factors. The clinical outcome, measured by the Apgar-scores and the transferal rate, was statistically significantly worse with the retarded children.

CONCLUSIONS

The maternal glucose metabolism influences the fetal growth not only with respect to macrosomia but also growth retardation. The growth curves that have been used until now wrongly do not take into consideration the maternal anthropometric data. In light of this, the former ought to be re-evaluated. The data of this study emphasize the necessity of need-adapted nutrition. Maybe also pregnant women with a growth retarded child need a dietary consultation.

Internal jugular vein thrombosis caused by resistance to activated protein C as a complication of ovarian hyperstimulation after in-vitro fertilization

We present a case of a 24 year old woman who became pregnant (twins) after human menopausal gonadotrophin (HMG)-induced ovarian stimulation, in-vitro fertilization (IVF) and subsequent embryo transfer. She developed a right internal jugular vein thrombosis as a complication of severe ovarian hyperstimulation syndrome (OHSS) 28 days after embryo transfer. The thrombosis developed in spite of anticoagulation with low-dose heparin. Later a resistance to activated protein C (APC) or Dahlbäck disease was diagnosed. Due to a new test procedure (accelerin inactivation test), the diagnosis was possible even under anticoagulation treatment. The coincidence of hyperstimulation and internal jugular vein thrombosis with the concurrent diagnosis of resistance to APC has not been published previously. The benefit of general screening for resistance to APC before admission to the IVF programme should be weighed. Targeted selection of a group of high-risk women would therefore be made possible.

Recurrent benign Müllerian papilloma of the vagina. Immunohistological findings and histogenesis

Vaginal papillomata are rare, particularly in children. The macroscopic appearance is suggestive of a botryoid rhabdomyosarcoma, which is more common in this age group. The histogenesis of these tumors is still controversial, the choices being mesonephric or Müllerian origin. In our case cytokeratins and intermediate filaments were looked for immunohistochemically. Squamous epithelium as well as the cylindrical epithelium expresses type I cytokeratins, an acidic polypeptide typical of cylindrical epithelium. A strong expression of EMA in both epithelial types and CEA staining of the cylindrical epithelium support the hypothesis that these papillomata derive from Müllerian epithelium. Recurrence as observed in our case has not been described before. Treatment involves the simple removal of the papilloma.

Die Wirkung verschiedener Gifte auf die Entstehung von Wasserstoff bei Belichtung anaerob inkubierter Chlorella pyrenoidosa

Mit Hilfe einer elektrochemischen H2-Meßmethode wurde ein vorübergehendes Auftreten von molekularem Wasserstoff bei Belichtung anaerob inkubierter Zellen beobachtet. Die H2-Menge lag in der Größenordnung von 1 · 10-5 Mol/l und war von der Inkubationszeit abhängig. Es wurde die Wirkung verschiedener Gifte auf diesen Effekt untersucht