Effect of quantum confinement on the dielectric function of PbSe

Monolayers of lead selenide nanocrystals of a few nanometers in height have been made by electrodeposition on a Au(111) substrate. These layers show a thickness-dependent dielectric function, which was determined using spectroscopic ellipsometry. The experimental results are compared with electronic structure calculations of the imaginary part of the dielectric function of PbSe nanocrystals. We demonstrate that the size-dependent variation of the dielectric function is affected by quantum confinement at well-identifiable points in the Brillouin zone, different from the position of the band-gap transition

A leap of faith? An interview study with professionals on the use of mitochondrial replacement to avoid transfer of mitochondrial diseases

STUDY QUESTION: What are the opinions of professionals in the field of genetics, reproductive science and metabolic diseases on the development of mitochondrial replacement technologies to be used in the context of medically assisted reproduction? SUMMARY ANSWER: Although concerns regarding safety remain, interviewees supported the development of nuclear transfer techniques to help women who are at risk of transferring a mitochondrial DNA disease to their offspring conceive a genetically related child. WHAT IS KNOWN ALREADY: Technological developments in the field of nuclear transfer have sparked new interest in the debate on the acceptability of the use of donor oocytes to prevent the transmission of mitochondrial diseases. For example, in the UK, extensive public consultations have been done to investigate whether such techniques would allow the passing of a law that involves making changes to a human oocyte or embryo before transfer to a woman's body. Until now, continental European countries seem to await the outcome of the British debate before themselves considering the arguments for and against this technology. STUDY DESIGN, SIZE, AND DURATION: We interviewed 12 professionals from Belgium and The Netherlands. PARTICIPANTS/MATERIALS, SETTING, AND METHODS: We conducted 12 interviews with fertility specialists, scientists, clinical geneticists, a pediatrician specialized in metabolic diseases and a specialist in metabolic diseases. The profiles of the interviewees varied but all had experience with mitochondrial diseases, either in treating patients or in providing counseling to patients or to prospective parents. The interviews were conducted face-to-face and took 30-45 min. The language of the interviews was Dutch. We analyzed the transcript of these interviews using QSR NVIVO 10 software to extract themes and categories. MAIN RESULTS AND THE ROLE OF CHANCE: This study has shown that, although amongst the professionals we interviewed there was support for the development and deployment of nuclear transfer, this support does not necessarily correspond to uniform opinions about the importance of having a genetically own child or the contribution of mitochondrial DNA to essential characteristics of an individual. LIMITATIONS, REASONS FOR CAUTION: In translating the quotes from Dutch to English some of the linguistic nuances may have been lost. We only interviewed 12 individuals, in two countries, whose view may not be representative of existing values and opinions that may be held by professionals worldwide on this matter. To further explore the issue at hand, a subsequent investigation of the opinions of people affected by mitochondrial diseases and of the general public is necessary. WIDER IMPLICATIONS OF THE FINDINGS: With this study we have demonstrated there is in principle support for the nuclear transfer technique from Dutch and Belgian professionals. Further research, both scientific and ethical, is needed to define the modalities of its possible introduction in the fertility clinic

Mutu Ikan Cakalang (Katsuwonus Pelamis L) Asap Yang Direndam Dengan Larutan Kulit Buah Manggis (Gracinia Mangostana Linn).

The purpose of this study was to determine the quality of smoked skipjack (Katsuwonus pelamis L) smoke pre-treated in a solution of mangosteen peel with a concentration of 3, 4 and 5%, with various soaking time, then stored and observed at 0, 3, 6, and 9 days. The results showed that the highest value of total plate count (TPC) was found in the fish sample storage for 9 days, soaking with a concentration of 3% for 30 minutes. Meanwhile, the lowest TPC value was discovered for the fish samples that did not undergo storage, and immersed in a solution of 5% for 30 minutes. Furthermore, the highest TVB value (Total Volatile bases) was detected in fish samples soaked with 3% solution of the mangosteen for 15 minutes (59.22mg N/100g) while the lowest value obtained on the fish sample marinated with 5% concentration for 15 minutes and did not experience storage (5.04mg N/100g)

Quantum Rod Emission Coupled to Plasmonic Lattice Resonances: A Collective Directional Source of Polarized Light

We demonstrate that an array of optical antennas may render a thin layer of randomly oriented semiconductor nanocrystals into an enhanced and highly directional source of polarized light. The array sustains collective plasmonic lattice resonances which are in spectral overlap with the emission of the nanocrystals over narrow angular regions. Consequently, different photon energies of visible light are enhanced and beamed into definite directions.Comment: 4 pages, 3 figure

Casein genetic variants in ovine Merino breed

The genetic polymorphism on Merina ewe milk was investigated, using polyacrylamide gel electrophoresis at pH 8.6 and ultra thin-layer isoelectric focusing techniques, according to Krause et al. (1988), and Chianese et al. (1992). The casein fractions identified were: - Seven as1-casein phenotypes: CC, BB, BC, AB, AC, BD and CD (Chianese et al.,1996). - Three as2-casein phenotypes, provisionally nominated F, S, and I. - Three b-casein phenotypes, also provisionally nominated K, L and M, because their genetic segregation is not well known yet. The phenotypical distribution of the observed casein fractions and their adjustment to a normal distribution is presented.El polimorfismo genético de la leche de oveja Merina fue investigado mediante electroforesis en gel de poliacrilamida a pH 8,6 (PAGE) e isoelectroenfoque en gel ultrafino (UTLIEF), siguiendo las técnicas descritas por Krause et al. (1988) y Chianese et al. (1992). Dentro de las fracciones caseínicas se identificaron siete fenotipos de as1-caseína (CC, BB, BC, AB, AC, BD y CD), según la nomenclatura establecida por Chianese et al. (1996). Mientras que, a nivel de as2- y b-caseína se han observado tres perfiles electroforéticos, denominados provisionalmente F, S e I; K, L y M respectivamente, ya que no se conoce su segregación genética. Se presenta la distribución fenotípica de las fracciones caseínicas estudiadas, así como su ajuste a la distribución normal

Dynamics and Ethics of Comprehensive Preimplantation Genetic Testing. A Review of the Challenges

BACKGROUND: Genetic testing of preimplantation embryos has been used for preimplantation genetic diagnosis (PGD) and preimplantation genetic screening (PGS). Microarray technology is being introduced in both these contexts, and is to be expected that also whole genome sequencing of blastomeres will become possible. The amount of extra information such tests will yield may prove to be beneficial for embryo selection, but also raise various ethical issues. We present an overview of the developments and an agenda-setting exploration of the ethical issues. METHODS: The paper is a joint endeavour by the presenters at an explorative 'campus meeting' organized by the European Society of Human Reproduction and Embryology in cooperation with the department of Health, Ethics & Society of the Maastricht University (The Netherlands). RESULTS: The increasing amount and detail of information that new screening techniques such as microarrays and whole genome sequencing offer does not automatically coincide with an increasing understanding of the prospects of an embryo. From a technical point of view, the future of comprehensive embryo testing may go together with developments in preconception carrier screening. From an ethical point of view, the increasing complexity and amount of information yielded by comprehensive testing techniques will lead to challenges to the principle of reproductive autonomy and the right of the child to an open future, and may imply a possible larger responsibility of the clinician towards the welfare of the future child. “Smart combinations” of preconception carrier testing and embryo testing may solve some of these ethical questions but could introduce others. CONCLUSION: As comprehensive testing techniques are entering the IVF clinic, there is a need for a thorough rethinking of traditional ethical paradigms regarding medically assisted reproduction.This article was written by Dr Ainsley Newson during the time of her employment with the University of Bristol, UK (2006-2012). Self-archived in the Sydney eScholarship Repository with permission of Bristol University, Sept 2014

The Belgian PCB and dioxin incident of January-June 1999: exposure data and potential impact on health.

In January 1999, 500 tons of feed contaminated with approximately 50 kg of polychlorinated biphenyls (PCBs) and 1 g of dioxins were distributed to animal farms in Belgium, and to a lesser extent in the Netherlands, France, and Germany. This study was based on 20,491 samples collected in the database of the Belgian federal ministries from animal feed, cattle, pork, poultry, eggs, milk, and various fat-containing food items analyzed for their PCB and/or dioxin content. Dioxin measurements showed a clear predominance of polychlorinated dibenzofuran over polychlorinated dibenzodioxin congeners, a dioxin/PCB ratio of approximately 1:50,000 and a PCB fingerprint resembling that of an Aroclor mixture, thus confirming contamination by transformer oil rather than by other environmental sources. In this case the PCBs contribute significantly more to toxic equivalents (TEQ) than dioxins. The respective means +/- SDs and the maximum concentrations of dioxin (expressed in TEQ) and PCB observed per gram of fat in contaminated food were 170.3 +/- 487.7 pg, 2613.4 pg, 240.7 +/- 2036.9 ng, and 51059.0 ng in chicken; 1.9 +/- 0.8 pg, 4.3 pg, 34.2 +/- 30.5 ng, and 314.0 ng in milk; and 32.0 +/- 104.4 pg, 713.3 pg, 392.7 +/- 2883.5 ng, and 46000.0 ng in eggs. Assuming that as a consequence of this incident between 10 and 15 kg PCBs and from 200 to 300 mg dioxins were ingested by 10 million Belgians, the mean intake per kilogram of body weight is calculated to maximally 25,000 ng PCBs and 500 pg international TEQ dioxins. Estimates of the total number of cancers resulting from this incident range between 40 and 8,000. Neurotoxic and behavioral effects in neonates are also to be expected but cannot be quantified. Because food items differed widely (more than 50-fold) in the ratio of PCBs to dioxins, other significant sources of contamination and a high background contamination are likely to contribute substantially to the exposure of the Belgian population

Sex chromosome positions in human interphase nuclei as studied by in situ hybridization with chromosome specific DNA probes

Two cloned repetitive DNA probes, pXBR and CY1, which bind preferentially to specific regions of the human X and Y chromosome, respectively, were used to study the distribution of the sex chromosomes in human lymphocyte nuclei by in situ hybridization experiments. Our data indicate a large variability of the distances between the sex chromosomes in male and female interphase nuclei. However, the mean distance observed between the X and Y chromosome was significantly smaller than the mean distance observed between the two X-chromosomes. The distribution of distances determined experimentally is compared with three model distributions of distances, and the question of a non-random distribution of sex chromosomes is discussed. Mathematical details of these model distributions are provided in an Appendix to this paper. In the case of a human translocation chromosome (XqterXp22.2::Yq11Y qter) contained in the Chinese hamster x human hybrid cell line 445 x 393, the binding sites of pXBR and CY1 were found close to each other in most interphase nuclei. These data demonstrate the potential use of chromosome-specific repetitive DNA probes to study the problem of interphase chromosome topography

Surprising findings following a Belgian food contamination with polychlorobiphenyls and dioxins.

We found that 12.1% of Belgian export meat samples from chicken or pork, unrelated to the PCB/dioxin crisis from 1999, contained more than 50 ng polychlorinated biphenyls (PCBs)/g fat and that 6.5% of samples contain more than 20 ng/g fat for the sum of 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) and its metabolites. Part of this background contamination stems from imported animal feed ingredients (fish flour and grains), sometimes contaminated by recent use of DDT, as can be deduced from the ratio between DDT and its main metabolite, 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE). However, after comparing PCB concentrations in fish flour and grains with those found in meat, we suggest that the high concentrations stem from recycled fat. This is the first paper describing background concentrations of PCBs in animal meat from Belgium