Encapsulation of yeast cells in colloidosomes

Polymeric colloidosomes encapsulating viable Baker's yeast cells were prepared. To make the capsules, an aqueous suspension of 153 nm poly(methyl methacrylate-co-butyl acrylate) latex particles plus yeast cells is emulsified in a continuous phase of sunflower oil. By adding a small amount of ethanol to the oil phase, the latex particles at the surface of the emulsion droplets aggregate, forming the colloidosome shells. The microcapsules have been examined using optical, confocal, and scanning electron microscopies. The viability of the yeast cells was tested using fluorescent molecular probes. The encapsulated Baker's yeast cells were able to metabolize glucose from solution, although at a slower rate compared to nonencapsulated yeast. This demonstrates diffusion limitation through the colloidosome shell. The diffusive resistance could be increased by manufacturing colloidosomes with a double latex shell.     

Guiding Teachers in the Use of a Standards‐Based Mathematics Curriculum: Teacher Perceptions and Subsequent Instructional Practices After an Intensive Professional Development Program

Reforms in mathematics education call for K‐12 teachers to employ standards‐based pedagogies, which embody the National Council for Teachers of Mathematics' principles and standards. In order to effectively support teachers' implementation of standards‐based curricula, professional development must be provided that meets teachers' needs. The professional development program in this study focused on the implementation of a standards‐based mathematics curriculum entitled Investigations in Number, Data, and Space (Investigations). This study uses Guskey's framework as a guide to examining teachers' perceptions of the impact of the professional development that they received; their perceptions of mathematics teaching and learning; and how elements of the professional development translated into practice. Twenty‐two participants were randomly selected from the 53 professional development participants to be interviewed and observed during their mathematics teaching. Using a constant comparison method, the data sources in this study highlighted themes surrounding teachers' experiences with professional development and the implementation of the curricula. The analysis of the data sources in this study highlighted themes surrounding teachers' experiences with professional development: teachers as learners, teachers as self‐evaluators, shifting paradigms, enactment of professional development content into practice, and the influence of the state standardized mathematics test. The results of this study have several implications for future professional development and also highlight some of the more general issues that teachers face when attempting to enact new knowledge and skills into their practice.     

Theoretical predictions of cofacial bis(actinyl) complexes of a stretched Schiff-base calixpyrrole ligand

Actinyl and actinyl-transition metal complexation by a polypyrrolic macrocycle with anthracenyl linkers between the N(4)-donor compartments was evaluated using relativistic density functional theory which predicts that a highly unusual cofacial bis-actinyl structure complex is stable.     

On the bifurcations and multiple endemic states of a single strain HIV model

The dynamics of a single strain HIV model is studied. The basic reproduction number R0 used as a bifurcation parameter shows that the system undergoes transcritical and saddle-node bifurcations. The usual threshold unit value of R0 does not completely determine the eradication of the disease in an HIV infected person. In particular, a sub-threshold value Rc is established which determines the system＇s number of endemic states： multiple if Rc 〈 Ro 〈 1, only one if Rc=Ro = 1, and none if R0 〈 Rc 〈 1.     

Oxo–Group‐14‐Element Bond Formation in Binuclear Uranium(V) Pacman Complexes

Simple and versatile routes to the functionalization of uranyl‐derived U^V–oxo groups are presented. The oxo‐lithiated, binuclear uranium(V)–oxo complexes [{(py)₃LiOUO}₂(L)] and [{(py)₃LiOUO}(OUOSiMe₃)(L)] were prepared by the direct combination of the uranyl(VI) silylamide “ate” complex [Li(py)₂][(OUO)(N”)₃] (N”=N(SiMe₃)₂) with the polypyrrolic macrocycle H₄L or the mononuclear uranyl (VI) Pacman complex [UO₂(py)(H₂L)], respectively. These oxo‐metalated complexes display distinct U? O single and multiple bonding patterns and an axial/equatorial arrangement of oxo ligands. Their ready availability allows the direct functionalization of the uranyl oxo group leading to the binuclear uranium(V) oxo–stannylated complexes [{(R₃Sn)OUO}₂(L)] (R=nBu, Ph), which represent rare examples of mixed uranium/tin complexes. Also, uranium–oxo‐group exchange occurred in reactions with [TiCl(OiPr)₃] to form U‐O? C bonds [{(py)₃LiOUO}(OUOiPr)(L)] and [(iPrOUO)₂(L)]. Overall, these represent the first family of uranium(V) complexes that are oxo‐functionalised by Group 14 elements.     

Tritium labelling of insect neurotransmitter and TAAR1 agonist (±)-octopamine

The tritiation of (±)-octopamine is described.