Methods for the synthesis of polyhydroxylated piperidines by diastereoselective dihydroxylation: Exploitation in the two-directional synthesis of aza-C-linked disaccharide derivatives

Background: Many polyhydroxylated piperidines are inhibitors of the oligosaccharide processing enzymes, glycosidases and glycosyltransferases. Aza-C-linked disaccharide mimetics are compounds in which saturated polyhydroxylated nitrogen and oxygen heterocycles are linked by an all-carbon tether. The saturated oxygen heterocycle has the potential to mimic the departing sugar in a glycosidase-catalysed reaction and aza-C-linked disaccharide mimetics may, therefore, be more potent inhibitors of these enzymes. Results: The scope, limitations and diastereoselectivity of the dihydroxylation of stereoisomeric 2-butyl-1-(toluene-4-sulfonyl)-1,2,3,6-tetrahydro-pyridin-3-ols is discussed. In the absence of a 6- substituent on the piperidine ring, the Upjohn (cat. OsO4, NMO, acetone-water) and Donohoe (OsO4, TMEDA, CH2Cl2) conditions allow complementary diastereoselective functionalisation of the alkene of the (2R*,3R*) diastereoisomer. However, in the presence of a 6-substituent, the reaction is largely controlled by steric effects with both reagents. The most synthetically useful protocols were exploited in the two-directional synthesis of aza-C-linked disaccharide analogues. A two-directional oxidative ring expansion was used to prepare bis-enones such as (2R,6S,2'S)-6- methoxy-2-(6-methoxy-3-oxo-3,6-dihydro-2H-pyran-2-ylmethyl)-1-(toluene-4-sulfonyl)-1,6- dihydro-2H-pyridin-3-one from the corresponding difuran. Selective substitution of its N,O acetal was possible. The stereochemical outcome of a two-directional Luche reduction step was different in the two heterocyclic rings, and depended on the conformation of the ring. Finally, twodirectional diastereoselective dihydroxylation yielded seven different aza-C-linked disaccharide analogues. Conclusion: A two-directional approach may be exploited in the synthesis of aza-C-linked disaccharide mimetics. Unlike previous approaches to similar molecules, neither of the heterocyclic rings is directly derived from a sugar, allowing mimetics with unusual configurations to be prepared. The work demonstrates that highly unsymmetrical molecules may be prepared using a two directional approach. The deprotected compounds may have potential as inhibitors of oligosaccharide-processing enzymes and as tools in chemical genetic investigations

First record of Eurasian Wryneck Jynx torquilla for Tanzania

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Promoting the Social Competence of Each and Every Child in Inclusive Early Childhood Classrooms

Social competence is part of a complex system that extends beyond the young child, necessitating prevention, assessment, and intervention. In this chapter, social competence in early childhood is examined considering existing research, developmental theory, and best practices and policies, many of which (on their own) address limited facets of a complex set of interactive competencies and outcomes. The potential and pitfalls of inclusive early childhood classroom structures relative to supporting interaction and social skill development are explored. Next, some of the most common social issues related to disabilities are described. These include deficits associated with specific developmental issues, such as emotional and behavioral issues autism, as well as others covered under the federal law (IDEA); universal practices for understanding and addressing student strengths and needs are shared. Finally, structures for addressing social interaction and supporting social competence in inclusive classrooms are presented. A conceptual model integrating professional preparation and the key components of inclusive preschool education for children with social competence needs is shared. These serve to illustrate practices and strategies which are supported by extant literature and acknowledge the dignity of children and their need for effective early childhood educational practices

Maximum Likelihood Detection for Cooperative Molecular Communication

In this paper, symbol-by-symbol maximum likelihood (ML) detection is proposed for a cooperative diffusion-based molecular communication (MC) system. In this system, a fusion center (FC) chooses the transmitter's symbol that is more likely, given the likelihood of the observations from multiple receivers (RXs). We propose three different ML detection variants according to different constraints on the information available to the FC, which enables us to demonstrate trade-offs in their performance versus the information available. The system error probability for one variant is derived in closed form. Numerical and simulation results show that the ML detection variants provide lower bounds on the error performance of the simpler cooperative variants and demonstrate that majority rule detection has performance comparable to ML detection when the reporting is noisy.Comment: 7 pages, 4 figurs. This work has been accepted by the IEEE ICC 201

Outcomes of Community-Based Infant/ Toddler Teacher Preparation: Tiered Supports for Pre-service early Childhood Education Teachers in Early Head Start

This study examined results associated with a field-based undergraduate early childhood teacher education program designed as a response to calls for enhanced field experiences and community-situated teacher education that narrows the preparation-to-practice gap. Specifically, classroom observations were used to assess undergraduates’ progress in developmentally appropriate adult-child interaction during a portion of a semester-long professional preparation sequence focused on infants and toddlers offered in an urban Early Head Start program serving low-income children. During the sequence, a model relying on guided apprenticeship with classroom teachers and continuous direct supervision from university faculty was employed. In addition, a tiered model including universal, targeted, and intensive supports was implemented in order to support candidates in identifying and developing specific areas of need. The participants in this study demonstrated greater responsivity and intentional engagement with infants and toddlers as a result of this intensive preparation sequence. Participants who did not show an initial increase in skills responded to targeted and and/or intensive intervention strategies. This model suggests that by refocusing early childhood teacher preparation through a lens of partnership between EHS teachers, university faculty, and early childhood special education (ECSE) teacher candidates, significant gains in developmentally appropriate practice can be achieved even for candidates early in a preparation program

Isometric tuples are hyperreflexive

An $n$-tuple of operators $(V_1,...,V_n)$ acting on a Hilbert space $H$ is said to be isometric if the row operator $(V_1,...,V_n) : H^n \to H$ is an isometry. We prove that every isometric $n$-tuple is hyperreflexive, in the sense of Arveson. For $n = 1$, the hyperreflexivity constant is at most 95. For $n \geq 2$, the hyperreflexivity constant is at most 6.Comment: 11 page

Re-envisioning the Role of Universities in Early Childhood Teacher Education: Community Partnerships for 21st-Century Learning

Despite contrasting views on the overlap of early childhood education and teacher education, opportunities abound for expanding the role of early childhood educators in broader teacher education discourse. University-based early childhood and Kindergarten-through-grade-12 teacher education share purposes, philosophies, and resources that should be explored to more effectively address the needs of diverse young children and their families. Community partnerships and a shift toward community-based teacher preparation present a context and opportunity for exploring the overlap of these two historically separate fields. In this paper, we present a framework for collaborative, field-based early childhood teacher preparation, situating birth-though-grade-12 teacher education in diverse community contexts and involving school and community personnel to achieve universal 21st century goals for the teaching and learning of young children