Megasonic agitation for enhanced electrodeposition of copper

In this paper we propose an agitation method based on megasonic acoustic streaming to overcome the limitations in plating rate and uniformity of the metal deposits during the electroplating process. Megasonic agitation at a frequency of 1 MHz allows the reduction of the thickness of the Nernst diffusion layer to less than 600 nm. Two applications that demonstrate the benefits of megasonic acoustic streaming are presented: the formation of uniform ultra-fine pitch flip-chip bumps and the metallisation of high aspect ratio microvias. For the latter application, a multi-physics based numerical simulation is implemented to describe the hydrodynamics introduced by the acoustic waves as they travel inside the deep microvias.

Risikowahrnehmung und psychologische Reaktionen in öffentlichen Krisensituationen am Beispiel von Terrorattentaten / Risk perception and psychological reactions in public crisis situations using the example of terror attacks

The reactions to the 9/11 terror attacks were immense in the western population. In the current review, the impact of terror attacks is presented with surveys, clinical interviews, and scientific polls, which were identified in a comprehensive literature search. Results show that the fear of further terror attacks is comparatively overestimated in the population and is associated with numerous psychological consequences and reactions. The overestimation of the probability of further terror attacks is related among other reasons to its unique features and its strong representation in the media. Several independent studies proved that the number of stress symptoms and psychiatric diagnoses is associated with a high risk perception in relation to terror attacks. This was not only the case for victims of terror attacks, but also for people indirectly exposed to the terror attacks. In addition, there is evidence that the number of the stress symptoms correlate with the duration of TV consumption of new findings about terror attempts. Methodologically, there is a critical lack of more in-depth analyses to explain the development of risk perceptions and its influence on mental and physical health. Because of the international importance and cross-cultural differences, an international standardization of research is desirable. [In German] Die Reaktionen auf die Terrorattentate vom 9. September 2001 in New York waren in der westlichen Bevölkerung immens. In der vorliegenden Übersichtsarbeit werden die Auswirkungen von Terrorattentaten durch Einbeziehung bevölkerungsrepräsentativer Untersuchungen, Surveys, klinischer Interviews und Einstellungsbefragungen dargestellt, die über eine deskriptive Literaturrecherche ermittelt wurden. Als Ergebnis des Reviews zeigt sich, dass die Angst vor weiteren Terrorattentaten in der Bevölkerung vergleichsweise hoch und mit zahlreichen psychologischen Folgen und Reaktionen assoziiert ist. Die Einschätzung der Auftretenswahrscheinlichkeit eines Terrorattentats hängt unter anderem mit den besonderen Charakteristika und der hohen medialen Präsenz des Themas zusammen. Die Anzahl der Stresssymptome bis hin zu psychiatrischen Diagnosen erwies sich in mehreren unabhängigen Untersuchungen mit einer hohen Risikowahrnehmung assoziiert. Dies ließ sich nicht nur bei den Opfern von Terrorattentaten, sondern auch bei indirekt Betroffenen zeigen. Darüber hinaus gibt es mehrfache Belege dafür, dass die Anzahl der Stresssymptome mit der Dauer des TV-Konsums über Neuigkeiten zu Terrorattentaten zusammenhing. Als methodische Kritik ist an den gegenwärtigen Untersuchungsszenarien einzuwenden, dass es derzeit keine tiefer gehenden Analysen zur Entwicklung der Risikowahrnehmung und zu ihrem Einfluss auf die Gesundheit gibt. Aufgrund der internationalen Bedeutung des Themas und der interkulturellen Unterschiede im Umgang mit Krisensituationen ist eine internationale Standardisierung von Untersuchungszugängen wünschenswert.

Differential cytotoxic and prooxidnant activity of knipholone and knipholone anthrone

Knipholone (KP) and knipholone anthrone (KA) are natural 4-phenylanthraquinone structural analogues with established differential biological effects including in vitro antioxidant [1] and antimicrobial properties [2]. The present study was designed to investigate the comparative in vitro cytotoxic activity and the possible mechanism of action of these two compounds. We demonstrated that KA is by order of magnitude more cytotoxic to mammalian cells than KP. In parallel with the demonstrated cytotoxic effect, KA but not KP induces prooxidative DNA damage in the presence of copper ions. In order to establish the possible involvement of reactive oxygen species in the KA-mediated prooxidative effect, we investigated the protective effect of several metal chelators and reactive oxygen species scavengers. Our data suggest that reactive oxygen species such as hydrogen peroxide are involved and a good correlation between prooxidative action, antioxidant effect and cytotoxicity is established for these two structural analogues. The chemistry, pharmacology and potential medicinal/toxicological potential of these compounds are discussed.

Comparative antioxidant, prooxidant and cytotoxic activity of sigmoidin A and eriodictyol

Sigmoidin A (SGN) is a prenylated flavanone derivative of eriodictyol (ERD) with reported moderate antioxidant, antimicrobial and anti-inflammatory activity. Since ERD and other structurally similar antioxidant phenolic compounds have been shown to induce prooxidative macromolecular damage and cytotoxicity in cancer cells, the comparative in vitro effects of these structural analogues on cancer cell viability and Cu(II)-dependent DNA damage were studied. In the presence of Cu(II) ions, both SGN and ERD (7.4-236 µM) caused comparable concentration-dependent pBR322 plasmid DNA strand scission. The DNA damage induced by SGN and ERD could be abolished by ROS scavengers, glutathione (GSH) and catalase as well as EDTA and a specific Cu(I) chelator neocuproine. Both ERD and SGN readily reduce Cu(II) to Cu(I) suggesting a prooxidative mechanism of DNA damage. In a cell free system, ERD and SGN did also show comparable radical scavenging activity. SGN was, however, by an order of magnitude more cytotoxic to cancer cells than ERD and this effect was significantly attenuated by GSH suggesting a prooxidative mechanism of cell death. A depletion of intracellular GSH level by SGN in cancer cells is also demonstrated.

Triterpenoid saponins from the cytotoxic root extract of Sideroxylon foetidissimum, an endemic Yucatecan medicinal plant

The flora of the Yucatan peninsula (Mexico) includes approximately 3000 plant species. Sideroxylon foetidissimum Jacq. subsp. gaumeri (Sapotaceae) is an endemic plant to the Yucatan peninsula; its fruit is edible and local people use the plant for medicinal purposes, although no details on its preparation or application are available [1,2]. A preliminary cytotoxic evaluation of the ethanolic root extract of S. foetidissimum revealed a potent activity against murine macrophage like cell line RAW 264.7 (IC50=39.54±4.11µg/mL). The systematic bioassay-guided fractionation of the extract resulted in the identification of the active saponin-containing fraction (IC50=33.69±6.19µg/mL). Four new triterpenoid saponins and a 1:1 mixture of two saponins were isolated from the active saponin- containing fraction. The evaluation of their cytotoxic activity revealed no activity for the tested pure saponins; however, the 1:1 mixture of saponins showed a potent activity (IC50=11.91±1.49µg/mL). The isolation of the saponins was carried out using semi-preparative HPLC. The structural assignments of the pure saponins were based on 1D (1H and 13C and DEPT-135) and 2D (COSY, HMBC, HSQC and TOCSY) NMR and mass spectrometry analyses. In this presentation, the isolation, identification and cytotoxic activity of the isolated compounds is discussed in more detail.

Epilobium parviflorum Schreb. - in vitro study of biological action

Epilobium parviflorum Schreb. (Onagraceae) is used for the treatment of benign prostatic hyperplasia (BPH), which is regarded as an endocrine disorder caused by age-related hormone imbalance and increased oxidative damage [1,2,3]. Epilobium can moderate the obstructive and the irritative symptoms of BPH [1] but its biological action is not entirely identified. E. parviflorum is rich in phytosterols, flavonoids (myricetin, quercetin, kaempferol and their glycosides), phenolic acids, catechins, ellagi- and gallotannins [4]. The potential biological effects of Epilobium parviflorum Schreb. have been investigated, in respect to its antioxidant, anti-inflammatory, enzyme-inhibitory and anti-androgenic effect. The whole-plant water extract showed higher antioxidant effect (IC50=1.65±0.05µg/mL) in DPPH assay than Trolox or ascorbic acid and inhibited the lipid peroxidation examined in TBA assay (IC50=2.31±0.18mg/mL). In concentrations 0.20-15.00µg/mL the extract possessed a protective effect comparable to catalase enzyme (2500 IU/mL), against oxidative damage generated on fibroblast cells. The examination of the COX-inhibitory effect showed that E. parviflorum had an anti-inflammatory effect (IC50=1.38±0.08µg/mL). Investigation of steroid receptor binding ability and the aromatase enzyme-inhibition showed negative results in the concentration range examined.

Molybdenum hexacarbonyl and DBU reduction of nitro compounds under microwave irradiation

An ethanolic mixture of molybdenurn hexacarbonyl and DBU mediates the reduction of nitroarenes to the corresponding anilines in excellent yields in 15-30 minutes under microwave irradiation.