The enhancement of stereoselectivity of a Pd-catalyzed three-component cascade reaction using parallel synthesis and multivariate analysis

Automated parallel synthesis with multivariate analysis was employed in the optimization of a Pd-catalyzed three-component cascade reaction of 7-buta-2,3-dienyl-1,3-dimethyl-3,7-dihydropurine-2,6-dione with iodobenzene and morpholine (see Scheme 1). Initially a range of reaction factors were analyzed using experimental design to optimize for selectivity, conversion, and impurity levels. Solvents and bases were screened separately as the substantial number of discrete variables involved is unsuited to the fractional factorial design used. Instead, a solvent principal component analysis (PCA) model was used in selection of solvents for screening, so gaining maximum variation in solvent properties. Similarly, tertiary amines were chosen by pKa for screening as bases alongside inorganic salts. This investigation yielded two-fold results, not only in enhancement of the reaction selectivity, but since significantly different findings were obtained on changing the solvent, the importance of the sequence of experimentation is also emphasized.     

Complexity, class dynamics, and distance learning

Classroom participants learn early on that each classroom has its own dynamic comprised of personalities, motivation levels, skills, and other variables. This paper explores features of complexity theory—nonlinearity and emergent self-organization—relevant to dynamics in physical or virtual classrooms. These central notions of complexity theory and their importance in composition classrooms help explain why students in virtual classrooms are often less successful than their physical classroom counterparts in negotiating the eddies of virtual interactions. The paper closes with a brief consideration of how teachers can interrogate all the elements of teaching and classroom context (whether physical or virtual) to influence the emergent dynamic of our classrooms.     

Working with Guanxi: An Assessment of the Implications of Globalisation on Business Networking in China

Cross cultural literature has suggested China has a business culture based on family networks or guanxi connections underpinned by strong Confucian ethics. We argue that Chinese business may have distinctly national cultural attributes (that international businesses ignore at their peril) but we reassess the continuing significance of these historical cultural concepts. We query whether a system of networks consolidated during fifty years of state‐owned enterprises can still have application on the considerably larger scale of multinational corporate business of today’s China. Interview data collected from Australian expatriates in China in 2001 is used to assess the relevance of guanxi for effective international operations in China from the perspective of Australian expatriate managers.     

The Chemistry and Biology of 6‐Hydroxyceramide,the Youngest Member of the Human Sphingolipid Family

Sphingolipids are crucial for the life of the cell. In land‐dwelling mammals, they are equally important outside the cell—in the extracellular space of the skin barrier—because they prevent loss of water. Although a large body of research has elucidated many of the functions of sphingolipids, their extensive structural diversity remains intriguing. A new class of sphingolipids based on 6‐hydroxylated sphingosine has recently been identified in human skin. Abnormal levels of these 6‐hydroxylated ceramides have repeatedly been observed in atopic dermatitis; however, neither the biosynthesis nor the roles of these unique ceramide subclasses have been established in the human body. In this Minireview, we summarize the current knowledge of 6‐hydroxyceramides, including their discovery, structure, stereochemistry, occurrence in healthy and diseased human epidermis, and synthetic approaches to 6‐hydroxysphingosine and related ceramides.     

A meta-analysis of the effects of texting on driving

Text messaging while driving is considered dangerous and known to produce injuries and fatalities. However, the effects of text messaging on driving performance have not been synthesized or summarily estimated. All available experimental studies that measured the effects of text messaging on driving were identified through database searches using variants of “driving” and “texting” without restriction on year of publication through March 2014. Of the 1476 abstracts reviewed, 82 met general inclusion criteria. Of these, 28 studies were found to sufficiently compare reading or typing text messages while driving with a control or baseline condition. Independent variables (text-messaging tasks) were coded as typing, reading, or a combination of both. Dependent variables included eye movements, stimulus detection, reaction time, collisions, lane positioning, speed and headway. Statistics were extracted from studies to compute effect sizes (r_c). A total sample of 977 participants from 28 experimental studies yielded 234 effect size estimates of the relationships among independent and dependent variables. Typing and reading text messages while driving adversely affected eye movements, stimulus detection, reaction time, collisions, lane positioning, speed and headway. Typing text messages alone produced similar decrements as typing and reading, whereas reading alone had smaller decrements over fewer dependent variables. Typing and reading text messages affects drivers’ capability to adequately direct attention to the roadway, respond to important traffic events, control a vehicle within a lane and maintain speed and headway. This meta-analysis provides convergent evidence that texting compromises the safety of the driver, passengers and other road users. Combined efforts, including legislation, enforcement, blocking technologies, parent modeling, social media, social norms and education, will be required to prevent continued deaths and injuries from texting and driving.     

TinyLVR: A utility for viewing single predictor multivariate models in terms of a two factor latent vector model

This paper describes an adaptation of Ergon's 2PLS approach (Compression into two-component PLS factorizations. J. Chemom. 2003; 17: 303-312.) to represent a single predictor regression model in terms of a two-factor latent vector model. The purpose of this reduction is to aid model interpretation and diagnostics. Non-orthogonal score vectors are produced from two orthonormal loading vectors: one identical to the first PLS loading vector, and a second built from the regression vector. Using an invertible matrix, the factorization can be alternatively represented by two orthogonal score vectors, one of which is proportional to centred predictions. An auxiliary set of loadings is also calculated, which captures a different model space, but is provided since its associated residuals have useful properties. Identities connecting the two model spaces are provided. The latent vector regression coefficients are not always least-squares estimates but can be represented as the solution to a two-term generalized ridge regression. Consequences of this are addressed. The utility of TinyLVR is demonstrated with example models built using stepwise variate selection and ridge regression.     

Microchemomechanical Systems

The development of microchemomechanical systems (MCMS) as an analogy to microelectromechanical systems (MEMS) is reviewed, with the distinction that the mechanical actuation of microscale structures is effected by chemical cues as opposed to electricity. The intellectual motivation to pursue MCMS, or the creation of integrated chemical‐stimuli‐responsive devices, is that such structures are widely observed in nature. From a practical standpoint, since chemicals can readily diffuse and produce changes over large distances, this approach is especially attractive in enabling wireless and autonomous devices at small size scales.     

Relationship between persistent organic pollutants (POPs) and ranging patterns in common bottlenose dolphins (Tursiops truncatus) from coastal Georgia, USA

Bottlenose dolphins (Tursiops truncatus) are apex predators in coastal southeastern U.S. waters; as such they are indicators of persistent organic pollutants (POPs) in coastal ecosystems. POP concentrations measured in a dolphin's blubber are influenced by a number of factors, including the animal's sex and ranging pattern in relation to POP point sources. This study examined POP concentrations measured in bottlenose dolphin blubber samples (n = 102) from the Georgia, USA coast in relation to individual ranging patterns and specifically, distance of sightings from a polychlorinated biphenyl (PCB) point source near Brunswick, Georgia. Dolphin ranging patterns were determined based upon 5 years of photo-identification data from two field sites approximately 40 km apart: (1) the Brunswick field site, which included the Turtle/Brunswick River Estuary (TBRE), and (2) the Sapelo field site, which included the Sapelo Island National Estuarine Research Reserve (SINERR). Dolphins were categorized into one of three ranging patterns from photo-identification data. Individuals with sighting histories exclusively within one of the defined field sites were considered to have either Brunswick or Sapelo ranging patterns. Individuals sighted in both field sites were classified as having a Mixed ranging pattern. Brunswick males had the highest concentrations of PCBs reported for any marine mammal. The pattern of PCB congeners was consistent with Aroclor 1268, a highly chlorinated PCB mixture associated with a Superfund site in Brunswick. PCB levels in Sapelo males were lower than in Brunswick males, but comparable to the highest levels measured in other dolphin populations along the southeastern U.S. Female dolphins had higher Aroclor 1268 proportions than males, suggesting that the highly chlorinated congeners associated with Aroclor 1268 may not be offloaded through parturition and lactation, as easily as less halogenated POPs. Individuals sighted farther from the Superfund point source had lower Aroclor 1268 proportions.     

A review of salt marsh dynamics

Salt marshes have been the subject of extensive research over many years. As well as gaining the interest of biologists, physical processes within the marsh have been measured in some detail since at least the 1920s. There have been various attempts to develop a fuller understanding of the inter‐relationship between physical and biological processes within salt marshes. Advances often go in step changes. Over the last 10–20 years, there has been such a change with the ability to capture and manipulate spatial data in sufficient detail to be able to resolve not only surface topography but also variations in vegetation and a number of relevant physical properties. This review paper seeks to highlight the advances in the understanding of salt marsh dynamics and our ability to investigate the relationships between physical and biological properties. Some consideration is also given to the areas that would benefit from new or further research.