Structure of droplet-epitaxy-grown InAs/GaAs quantum dots

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98673/1/ApplPhysLett_98_243115.pd

R-Parity Violation and Non-Abelian Discrete Family Symmetry

We investigate the implications of R-parity violating operators in a model with family symmetry. The family symmetry can determine the form of R-parity violating operators as well as the Yukawa matrices responsible for fermion masses and mixings. In this paper we consider a concrete model with non-abelian discrete symmetry Q_6 which contains only three R-parity violating operators. We find that ratios of decay rates of the lepton flavor violating processes are fixed thanks to the family symmetry, predicting BR(tau to 3e)/BR(tau to 3mu) ~ 4 m_{mu}^2/m_{tau}^2.Comment: 20 pages, 3 figure

Cerebral monitoring with transcranial Doppler ultrasonography improves neurologic outcome during repairs of acute type A aortic dissection

ObjectiveNeurologic complications after repair of acute type A aortic dissection remain significant. The use of power M-mode transcranial Doppler monitoring to verify cerebral blood flow during these repairs might decrease cerebral ischemia by correcting malperfusion. The purpose of this study was to analyze the use of power M-mode transcranial Doppler monitoring during repairs of acute type A dissection with regard to neurologic outcome.MethodsWe performed a prospective study of patients undergoing repairs of acute type A aortic dissection. Repairs included profound hypothermic circulatory arrest and retrograde cerebral perfusion. Patients in whom transcranial Doppler monitoring was used to monitor cerebral blood flow and modify operative technique during repair (study group) were compared with those without monitoring and modification (control group).ResultsBetween September 2001 and October 2003, we repaired 56 cases of acute type A dissection. Power M-mode transcranial Doppler monitoring was used in 50% (28/56) of cases. Power M-mode transcranial Doppler monitoring altered operative cannulation and guided retrograde cerebral perfusion flow in 28.5% (8/28) and 78.6% (22/28) of cases, respectively. Two patients presented with preoperative stroke, one in each group. One operative death occurred in each group. In-hospital mortality and the occurrence of new stroke were not significantly different between the 2 groups. Temporary neurologic dysfunction occurred less often in the study group (14.8% [4/27] vs 51.8% [14/27], P = .008).ConclusionsIdentification of cerebral malperfusion requires cerebral monitoring. By ensuring cerebral blood flow by using power M-mode transcranial Doppler monitoring and correcting cerebral malperfusion by modifying operative technique, neurologic outcome was improved during repairs of acute type A aortic dissection

A Novel Translocation Breakpoint within the BPTF Gene Is Associated with a Pre-Malignant Phenotype

Partial gain of chromosome arm 17q is an abundant aberrancy in various cancer types such as lung and prostate cancer with a prominent occurrence and prognostic significance in neuroblastoma – one of the most common embryonic tumors. The specific genetic element/s in 17q responsible for the cancer-promoting effect of these aberrancies is yet to be defined although many genes located in 17q have been proposed to play a role in malignancy. We report here the characterization of a naturally-occurring, non-reciprocal translocation der(X)t(X;17) in human lung embryonal-derived cells following continuous culturing. This aberrancy was strongly correlated with an increased proliferative capacity and with an acquired ability to form colonies in vitro. The breakpoint region was mapped by fluorescence in situ hybridization (FISH) to the 17q24.3 locus. Further characterization by a custom-made comparative genome hybridization array (CGH) localized the breakpoint within the Bromodomain PHD finger Transcription Factor gene (BPTF), a gene involved in transcriptional regulation and chromatin remodeling. Interestingly, this translocation led to elevation in the mRNA levels of the endogenous BPTF. Knock-down of BPTF restricted proliferation suggesting a role for BPTF in promoting cellular growth. Furthermore, the BPTF chromosomal region was found to be amplified in various human tumors, especially in neuroblastomas and lung cancers in which 55% and 27% of the samples showed gain of 17q24.3, respectively. Additionally, 42% percent of the cancer cell lines comprising the NCI-60 had an abnormal BPTF locus copy number. We suggest that deregulation of BPTF resulting from the translocation may confer the cells with the observed cancer-promoting phenotype and that our cellular model can serve to establish causality between 17q aberrations and carcinogenesis

A General Classification of Three-Neutrino Models and U_e3

A classification of models with three light neutrinos is given. This classification includes virtually all of the three-neutrino models proposed in the last few years, of which there are approximately one hundred. The essential ideas, attractive features, and characteristic problems of the different classes of model are discussed. The classification is based principally on how the large \nu_{\mu} - \nu_{\tau} mixing is obtained. A general discussion of the mixing parameter U_{e3} is then given, showing what values are to be expected for it in each type of model.Comment: 37 pages, LaTex. Several serious typos correcte

Surface X-Ray Diffraction Results on the III–V Droplet Heteroepitaxy Growth Process for Quantum Dots: Recent Understanding and Open Questions

In recent years, epitaxial growth of self-assembled quantum dots has offered a way to incorporate new properties into existing solid state devices. Although the droplet heteroepitaxy method is relatively complex, it is quite relaxed with respect to the material combinations that can be used. This offers great flexibility in the systems that can be achieved. In this paper we review the structure and composition of a number of quantum dot systems grown by the droplet heteroepitaxy method, emphasizing the insights that these experiments provide with respect to the growth process. Detailed structural and composition information has been obtained using surface X-ray diffraction analyzed by the COBRA phase retrieval method. A number of interesting phenomena have been observed: penetration of the dots into the substrate (“nano-drilling”) is often encountered; interdiffusion and intermixing already start when the group III droplets are deposited, and structure and composition may be very different from the one initially intended

Introduction: Multimodal Anthropology and the Politics of Invention

This essay and the articles included in this special issue theorize the possibilities – and pitfalls – that emerge as anthropologists utilise a combination of audio, video, text, still images, performance methodologies, and web platforms to iteratively, collaboratively, and sensually generate relations with research participants, interdisciplinary colleagues and beyond. We are not necessarily interested in developing multimedia approaches to representing or disseminating anthropological knowledge – rather, we are concerned with how multimodality may contribute to a politics of invention for the discipline. We argue that multimodality offers a line of flight for an anthropology yet to come: multi-sensorial rather than text-based, performative rather than representational, and inventive rather than descriptive. This reimagined anthropology requires a move away from established forms of authorship, representation and academic publishing towards projects that experiment with unanticipated forms, collaborations, audiences and correspondences – including questioning what the open in Open Access should signify, as Anand Pandian (2018) has compellingly argued. As importantly, a focus on multimodality and invention invites a reconsideration of the pedagogy of anthropology – both in the sense of what gets formally taught within the disciplinary canon, and in relation to the manifold ways of teaching and learning together that emerge during fieldwork, not always made visible, and which exceed the textual and conceptual domain. Indeed, we use multimodality and invention to refer to the multiple ways of doing ethnography - and the resulting multiple anthropologies - that create ways of knowing and learning together differently. In the essay that follows we offer several provocations that multimodality and invention produce with regards to pedagogy, publication, and collaboration – which are picked up in novel ways in each of the articles included as part of this collection. Our essay is not meant as an enclosure, or a boundary, but rather a framing – that is, a point of view or an orientation to the multiple questions that emerge in each of the essays, where the respective anthropologists rethink engagement, form, and purpose in their ethnographic endeavours. We draw from John Jackson Jr. to argue that framing is at once “a gesture toward contextualization (a conceptual framing of the relevant issues) and a singular impression captured in time (as in the presentation of a framed painting or the relative irreducibility of a film or video still)”. Taking Jackson Jr.’s second point to heart, we offer this introductory essay as a still image by which to see with and through the ethnographic engagements of others. In this still image, the concepts of multimodality and invention are unpacked and interrogated in ways we hope offer an alternative way to think about ethnography and anthropological theory in a moment where the discipline is grappling with how to find ways to engage more effectively with the increasingly fractured and precarious worlds we inhabit

Deficient histone H3 propionylation by BRPF1-KAT6 complexes in neurodevelopmental disorders and cancer

Lysine acetyltransferase 6A (KAT6A) and its paralog KAT6B form stoichiometric complexes with bromodomain- and PHD finger-containing protein 1 (BRPF1) for acetylation of histone H3 at lysine 23 (H3K23). We report that these complexes also catalyze H3K23 propionylation in vitro and in vivo. Immunofluorescence microscopy and ATAC-See revealed the association of this modification with active chromatin. Brpf1 deletion obliterates the acylation in mouse embryos and fibroblasts. Moreover, we identify BRPF1 variants in 12 previously unidentified cases of syndromic intellectual disability and demonstrate that these cases and known BRPF1 variants impair H3K23 propionylation. Cardiac anomalies are present in a subset of the cases. H3K23 acylation is also impaired by cancer-derived somatic BRPF1 mutations. Valproate, vorinostat, propionate and butyrate promote H3K23 acylation. These results reveal the dual functionality of BRPF1-KAT6 complexes, shed light on mechanisms underlying related developmental disorders and various cancers, and suggest mutation-based therapy for medical conditions with deficient histone acylation

Deficient histone H3 propionylation by BRPF1-KAT6 complexes in neurodevelopmental disorders and cancer

Lysine acetyltransferase 6A (KAT6A) and its paralog KAT6B form stoichiometric complexes with bromodomain- and PHD finger-containing protein 1 (BRPF1) for acetylation of histone H3 at lysine 23 (H3K23). We report that these complexes also catalyze H3K23 propionylati