A Baker–Venkataraman retro-Claisen cascade delivers a novel alkyl migration process for the synthesis of amides

A simple extension of the carbamoyl Baker-Venkataraman rearrangement has been developed. If residual water in the reaction is not strictly excluded a Baker-Venkataraman retro-Claisen cascade takes place, giving amide products, in which an alkyl group apparently migrates between two functionalities of the substrate

Mechanism and Application of Baker–Venkataraman O→C Acyl Migration Reactions

This literature review focuses on the O→C acyl migration of aryl esters to yield the corresponding 1,3-dicarbonyl products—a reaction known as the Baker–Venkataraman rearrangement—and outlines their subsequent transformations. The purpose of the review is to highlight the utility of the rearrangement which provides a key step in the synthesis of various heterocyclic motifs. The scope of the Baker–Venkataraman rearrangement is illustrated by way of numerous examples of its application, and in doing so, the review contains over 100 references and covers just over 100 years of the literature, from the first report of the rearrangement by Auwers in 1910 up to more recent examples in the past few years. 1 Introduction 2 Historical Perspective 3 Mechanism 4 Applications: General Routes to Heterocycles 4.1 Flavones and Flavanones 4.2 Xanthones 4.3 Chromones 4.4 Coumarins 4.5 Anthrapyran and Anthracyclin Antibiotics 4.6 Benzopyrans 5 The Retro-Baker–Venkataraman Rearrangement 6 Summary and Outloo

Electronic correlations in the Hubbard model on a bi-partite lattice

In this work we study the Hubbard model on a bi-partite lattice using the coupled-cluster method (CCM). We first investigate what, within this approach, allows us to reproduce the zero order parameter in the 1D model, as predicted by the exact solution. We show that we need a critical correlation in some of the coupled-cluster model coefficients to reproduce this result, as can be obtained by applying some very accurate results using the CCM for the Heisenberg model. Using the same approach we then tackle the 2D Hubbard model on a square and a honeycomb lattice, both of which can be thought to represent 2D materials. We also analyse the charge and spin excitations, with reasonable results.Comment: Major update to previous versio

On The Modeling of OpenFlow-based SDNs: The Single Node Case

OpenFlow is one of the most commonly used protocols for communication between the controller and the forwarding element in a software defined network (SDN). A model based on M/M/1 queues is proposed in [1] to capture the communication between the forwarding element and the controller. Albeit the model provides useful insight, it is accurate only for the case when the probability of expecting a new flow is small. Secondly, it is not straight forward to extend the model in [1] to more than one forwarding element in the data plane. In this work we propose a model which addresses both these challenges. The model is based on Jackson assumption but with corrections tailored to the OpenFlow based SDN network. Performance analysis using the proposed model indicates that the model is accurate even for the case when the probability of new flow is quite large. Further we show by a toy example that the model can be extended to more than one node in the data plane.Comment: Published in Proceedings of CS & IT for NeCOM 201

The development of a speech and language screening test for Maltese older persons

Aim: To develop the first screening test for Maltese speaking older adults with acquired language difficulties based on normative data, referred to in the study as Language Screening Test for the Elderly (LeST). Methodology: Normative data were collected from a representative sample of 77 elders living in the community, through cluster sampling from the five regions of Malta. Inclusion criteria: i) functional hearing abilities, ii) no history of neurological disorders, and iii) no cognitive impairment. Eighteen subjects were excluded. Factors taken into account: a) age (60 to 79 years and 80+ years), b) gender, c) educational background, d) literacy and e) bilingualism. A pilot study was carried out on 20 participants. Data collection was carried out at day centres by four speech language pathologists (SLPs). The LeST was also administered on ten subjects with aphasia and results were compared to the normal population. Results: Correlation and comparative statistical analysis of the data revealed that 1) scores were not affected by gender, age or locality, 2) p-values reach significance for factors related to bilingualism and literacy, and 3) the mean scores differ significantly between the control and test group. A cut-off point for receptive skills and one for expressive skills were also obtained. Conclusion: The test is valid for the purpose of language screening and would serve to ensure early identification of language impairment.peer-reviewe

Effects of Black Raspberry Extract on Myeloid Cell Differentiation and T lymphocyte Function

Dietary agents are important factors in regulating the development of diseases such as cancer. Several in vitro and animal studies have provided evidence that dietary intervention can prevent cancer development. In addition, studies show that many cancer patients already use natural products or supplements so it is valuable to explore how these agents might benefit health. Black raspberries are a good example of a dietary super-food. Despite data showing that this whole food or metabolites within it can inhibit cancer cell growth in vitro and in animal models, we do not know the mechanisms by which they act. We studied the effect of lyophilized black raspberry extract (BRB-E) and black raspberry metabolites, cyanadin-3-rutinoside (C3R) and quercetin-3-rutinoside (Q3R), on T lymphocyte function and Myeloid Derived Suppressor Cell (MDSC) expansion in vitro. T lymphocytes are important for the ability to detect and eliminate cancer. In contrast, MDSCs can suppress the immune system and prevent cytotoxic cells from recognizing and eliminating tumor cells. Pro- inflammatory cytokines and proteins such as phosphorylated STAT3 drive MDSC expansion. We hypothesized that lyophilized black raspberries or bioactive compounds derived from them would reduce the inflammatory changes that promote tumor development or metastasis. We observed that BRB-E and its metabolites C3R and Q3R suppressed T cell proliferation. We also determined that BRB-E enhanced T cell migration via CXCR3 receptor upregulation. Furthermore, BRB-E and its metabolites inhibited in vitro MDSC differentiation and STAT3 phosphorylation. These data suggest mechanisms by which black raspberry can be immunomodulatory and can be applied to regulating diseases such as cancer.Pelotonia Undergraduate Research FellowshipA five-year embargo was granted for this item.Academic Major: Biolog