Extraktstoffgehalt von Swietenia macrophylla King

Ohne Zusammenfassung     

Elektrische Darstellung mathematischer Funktionen

Zusammenfassung Der Aufsatz zeigt Verfahren und Schaltungen, nach welchen jede algebraische Funktionn-ten Grades undm-ter Ordnung dargestellt und gelöst werden kann. Einige Anwendungsbeispiele aus der Meß- und Regeltechnik sowie der Fall einer elektrischen Rechenmaschine für Gleichungenm-ten Grades undn-ter Ordnung werden kurz gestreift. Über geometrische und transzendente Funktionen sowie über Anwendungen und praktische Probleme soll in einigen späteren Folgen berichtet werden.     

Influence of the tetravalent cation on the high-voltage electrochemical activity of LiNi0.5M1.5O4 spinel cathode materials

The electrochemical properties of substituted LiNi_0.5Mn_1.5−xM_xO₄ spinels at high potential (>4 V vs Li⁺/Li) have been investigated for M = Ti and Ru, in order to determine the role of the tetravalent cation in such systems where nickel is a priori the only electroactive species. These systems are found to form extended solid solutions (up to x = 1.3 and x = 1.0 for Ti and Ru, respectively) that were characterized by X-ray diffraction and Raman spectroscopy. Titanium substitution induces a drastic decrease in high potential electrochemical capacity, whereas the capacity is maintained and the kinetics are even improved in the presence of ruthenium. These results are completed by new results on the Li_4−2xNi_3xTi_5−xO₁₂ spinel system, which shows not any high potential activity in spite of the presence of up to 0.5 Ni²⁺ per spinel formula unit on the octahedral site. Taking into account previous data on LiNi_0.5Ge_1.5O₄, we clearly show that even if the tetravalent cation does not participate in the overall redox reaction, electrochemical activity is only possible when nickel is surrounded by tetravalent cations able to accept a local variation of valence (Mn, Ru), whereas full-shell cations such as Ti⁴⁺ and Ge⁴⁺ block the necessary electron transfer pathways in the spinel oxide electrode.     

Effect of storage on extractives from particle surfaces of softwood and hardwood raw materials for wood pellets

When wood pellet raw material (dried sawdust and shavings) is stored for six months, wood pellet producers can observe an increased pellet mill capacity and pellet quality. To investigate the storage effect on the raw material and the possibilities for accelerating the effect, the effect of storage on surface extractives of the raw material was studied. Softwood and hardwood raw material was stored for six months, and the effect of the storage on the composition and concentration of the extractives on particle surface peelings was analyzed. Furthermore, the effect of storage at elevated temperatures was analyzed. The acetone extracts of peelings were analyzed by gas chromatography mass spectrometry (GC-MS), and multivariate regression modelling on the chemical composition was made to compare the effects of storage at elevated temperatures to the normal storage. The analysis showed that the extractive concentrations of the surface material were initially high and that these concentrations further increased during storage. Compound analyses showed that the concentrations of triterpenoid and steroidal structures increased during the storage period, whereas the concentrations of fatty acids and diterpenoid structures decreased during storage. It is suggested that this reflects oxidation and polymerization reactions of the fatty acids and diterpenoid structures. Modelling of the softwood storage proved good linear correlation of specific compound concentration changes to storage, whereas hardwood showed large uncertainties. It was shown that storage at higher temperatures accelerated the changes in extractive concentrations for softwood, whereas it was non-significant for hardwood. The study indicates that the improvement for the wood pellet production connected to raw material storage could be related to changes in the amount and composition of surface extractives for softwoods, whereas the effect for hardwoods is less certain.     

Polygonal Model Fitting

The celebrated minimum inertia line problem is reconsidered: a line is to be fitted to a planar cloud of points so that the sum of squared distances of all points to the line becomes minimal. The classical algebraic solution based on the tensor of inertia is complemented by a closed form trigonometric solution allowing various generalizations including the fit of elastic polygons. Proper polygons will be fitted numerically with non-closed partial solutions being reduced to the lowest dimension possible. This is complemented by segmentation heuristics for the measurement cloud.The approach allows to solve the robot localization problem with high accuracy for position and orientation to be inferred from distance measurements in a known polygonal environment. The essential feature of the current approach is to fit the polygonal geometry as a whole.     

Cerebral cysticercosis: why it should be treated

BACKGROUND: In Guadeloupe, cases of neurocysticercosis have been rarely observed in people recently immigrated from Haiti. We followed 2 women with seizures, associated with meningitis or encephalitis. CASE REPORT: Computed tomography scan and muscle X-ray have displayed specific features of cysticercosis with small diffuse calcifications. This was associated with positive antibodies for cysticercosis. After respectively 5 and 17 years, these patients developed recurrent manifestations of neurocysticercosis with subacute, quite silent meningitis after pregnancy, with CSF increased cells count (180 lymphocytes/mm3), raised protein level (0.6 g/l) and positive antibodies for cysticercosis in the first case, and cortical granuloma with fever and repetitive seizures in the second. DISCUSSION: These observations suggest that the patients were chronically infested, for more than 5 years. Although the brain lesions were quiescent for many years, new lesions responsible for inflammatory cysts occurred while they still lived outside her native endemic area. In such cases, treatment would benefit to the patient by breaking down the auto-infestation cycle.     

Defibrillation efficacy with endocardial electrodes is influenced by reductions in cardiac preload

Several studies were undertaken to develop three-dimensional (3-D) cell culture models that allow conditions closer to the in vivo situation. To this end, alginate gels were tested as a 3-D cell culture model that might be useful in the study of the effects of UVA on human dermal fibroblasts. Cell culture in alginate gels and the irradiation conditions were optimized. Results showed that optimized cultures in alginate gels experienced considerable cell death on UVA irradiation compared to the classical monolayer cell culture. Viability tests (cell counting and neutral red assay) were performed to show that only UVA-irradiated alginate gels were responsible for this cytotoxicity. The implication of oxygen species in the phototoxicity induced by ultraviolet light has already been described; for this reason we investigated whether oxygen species were involved in the cytotoxicity induced by alginate upon UVA irradiation. It appeared that superoxide anion is not implicated.     

Short-term oral endothelin-receptor antagonist therapy in conventionally treated patients with symptomatic severe chronic heart failure

BACKGROUND: The vasoconstrictor peptide endothelin-1 (ET-1) is important for increased vascular tone in patients with chronic heart failure, but the effects of endothelin-receptor blockade in addition to conventional triple therapy are unknown. METHODS AND RESULTS: Thirty-six men (mean age+/-SD, 55+/-8 years) with symptomatic heart failure (NYHA class III; left ventricular ejection fraction, 22.4+/-4.5%) despite treatment with diuretics, digoxin, and ACE inhibitors received, in a double-blind and randomized fashion, either additional oral bosentan (1.0 g BID; n=24) or placebo (n=12) over 2 weeks. Hemodynamic and hormonal (plasma ET-1, norepinephrine, renin activity, and angiotensin II) measurements were obtained before and repeatedly for 24 hours after administration of bosentan on days 1 and 14. Bosentan was discontinued in 1 patient with symptomatic hypotension, and 2 patients (bosentan group) declined hemodynamic investigations on day 14. Compared with placebo, bosentan on day 1 significantly decreased mean arterial pressure (difference from baseline over 12 hours [95% CIs], -13.9% [-16.0% to -11.7%]), pulmonary artery mean (-12.9% [-17. 4% to -8.3%]) and capillary wedge (-14.5% [-20.5% to -8.5%]) pressures, and right atrial pressure (-20.2% [-29.4% to -11.0%]). Cardiac output increased (15.1% [10.7% to 19.7%]), but heart rate was unchanged. Both systemic (-24.2% [-28.1% to -20.3%]) and pulmonary (-19.9% [-28.4% to -11.4%]) vascular resistance were reduced. After 2 weeks, cardiac output had further increased (by 15. 2% [10.8% to 19.6%]) and systemic (-9.3% [-12.3% to -6.4%]) and pulmonary (-9.7% [-16.3% to -3.1%]) vascular resistances further decreased compared with day 1. Heart rate remained unchanged. Plasma ET-1 levels increased after bosentan, but baseline levels of the other hormones were unchanged. CONCLUSIONS: Additional short-term oral endothelin-receptor antagonist therapy improved systemic and pulmonary hemodynamics in heart failure patients who were symptomatic with standard triple-drug therapy. Further investigations are warranted to characterize the effects of long-term endothelin-receptor antagonist therapy on symptoms, morbidity, and mortality in such patients.