Black and Brown Students’ Mathematics Anxiety in Elementary School: The Use of Restorative Justice Circles and Critical Concepts of Care, Hope, and Love

Children navigate their world and are constantly making meaning of their experiences. Through this meaning making, children are also constructing their identities. Black and Brown children have an added layer of identity construction compared to their White peers. Black and Brown students develop their racial identity in conjunction with multiple other identities. This paper focuses specifically on how Black and Brown students construct a mathematics identity that is meaningful to their racial identity in order to help lessen their mathematics anxiety. I argue that the use of Restorative Justice Circles (RJC) in classrooms will allow for students to bring their own identity into the communal space of the classroom while also fostering the construction of a mathematics identity. Through the use of critical concepts of care, educators can create a more reciprocal relationship with their students. RJC allow students to better understand who they are, what they identify with, what that means for them in the world, and how they view themselves in relation to math content learning. Black and brown students need more spaces in school where they are able to talk about their identity, including their identity in relation to mathematics learning. A proposal is offered to use these concepts to improve their relationships and levels of trust with their teacher and peers and to help them feel intrinsically connected with their mathematics work. I believe that RJC, critical concepts of care, and providing students with tools to address their anxiety is the biggest precursor to Black and Brown students feeling success in the mathematics classroom

A transient network of telechelic polymers and microspheres : structure and rheology

We study the structure and dynamics of a transient network composed of droplets of microemulsion connected by telechelic polymers. The polymer induces a bridging attraction between droplets without changing their shape. A viscoelastic behaviour is induced in the initially liquid solution, characterised in the linear regime by a stretched exponential stress relaxation. We analyse this relaxation in the light of classical theories of transient networks. The role of the elastic reorganisations in the deformed network is emphasized. In the non linear regime, a fast relaxation dynamics is followed by a second one having the same rate as in the linear regime. This behaviour, under step strain experiments, should induce a non monotonic behaviour in the elastic component of the stress under constant shear rate. However, we obtain in this case a singularity in the flow curve very different from the one observed in other systems, that we interpret in terms of fracture behaviour.Comment: 9 pages, 4 figure

“Cross” Supermicelles via the Hierarchical Assembly of Amphiphilic Cylindrical Triblock Comicelles

Self-assembled “cross” architectures are well-known in biological systems (as illustrated by chromosomes, for example); however, comparable synthetic structures are extremely rare. Herein we report an in depth study of the hierarchical assembly of the amphiphilic cylindrical P–H–P triblock comicelles with polar (P) coronal ends and a hydrophobic (H) central periphery in a selective solvent for the terminal segments which allows access to “cross” supermicelles under certain conditions. Well-defined P–H–P triblock comicelles M­(PFS-<i>b</i>-PtBA)-<i>b</i>-M­(PFS-<i>b</i>-PDMS)-<i>b</i>-M­(PFS-<i>b</i>-PtBA) (M = micelle segment, PFS = polyferrocenyldimethylsilane, PtBA = poly­(<i>tert</i>-butyl acrylate), and PDMS = polydimethylsiloxane) were created by the living crystallization-driven self-assembly (CDSA) method. By manipulating two factors in the supermicelles, namely the H segment-solvent interfacial energy (through the central H segment length, <i>L</i>₁) and coronal steric effects (via the PtBA corona chain length in the P segment, <i>L</i>₂ related to the degree of polymerization DP₂) the aggregation of the triblock comicelles could be finely tuned. This allowed a phase-diagram to be constructed that can be extended to other triblock comicelles with different coronas on the central or end segment where “cross” supermicelles were exclusively formed under predicted conditions. Laser scanning confocal microscopy (LSCM) analysis of dye-labeled “cross” supermicelles, and block “cross” supermicelles formed by addition of a different unimer to the arm termini, provided complementary characterization to transmission electron microscopy (TEM) and dynamic light scattering (DLS) and confirmed the existence of these “cross” supermicelles as kinetically stable, micron-size colloidally stable structures in solution

Monodisperse Cylindrical Micelles and Block Comicelles of Controlled Length in Aqueous Media

Cylindrical block copolymer micelles have shown considerable promise in various fields of biomedical research. However, unlike spherical micelles and vesicles, control over their dimensions in biologically relevant solvents has posed a key challenge that potentially limits in depth studies and their optimization for applications. Here, we report the preparation of cylindrical micelles of length in the wide range of 70 nm to 1.10 μm in aqueous media with narrow length distributions (length polydispersities <1.10). In our approach, an amphiphilic linear-brush block copolymer, with high potential for functionalization, was synthesized based on poly­(ferrocenyldimethylsilane)-<i>b</i>-poly­(allyl glycidyl ether) (PFS-<i>b</i>-PAGE) decorated with triethylene glycol (TEG), abbreviated as PFS-<i>b</i>-(PEO-<i>g</i>-TEG). PFS-<i>b</i>-(PEO-<i>g</i>-TEG) cylindrical micelles of controlled length with low polydispersities were prepared in <i>N</i>,<i>N</i>-dimethylformamide using small seed initiators via living crystallization-driven self-assembly. Successful dispersion of these micelles into aqueous media was achieved by dialysis against deionized water. Furthermore, B–A–B amphiphilic triblock comicelles with PFS-<i>b</i>-poly­(2-vinylpyridine) (P2VP) as hydrophobic “B” blocks and hydrophilic PFS-<i>b</i>-(PEO-<i>g</i>-TEG) “A” segments were prepared and their hierarchical self-assembly in aqueous media studied. It was found that superstructures formed are dependent on the length of the hydrophobic blocks. Quaternization of P2VP was shown to cause the disassembly of the superstructures, resulting in the first examples of water-soluble cylindrical multiblock comicelles. We also demonstrate the ability of the triblock comicelles with quaternized terminal segments to complex DNA and, thus, to potentially function as gene vectors

Transformation and patterning of supermicelles using dynamic holographic assembly

Although the solution self-assembly of block copolymers has enabled the fabrication of a broad range of complex, functional nanostructures, their precise manipulation and patterning remain a key challenge. Here we demonstrate that spherical and linear supermicelles, supramolecular structures held together by non-covalent solvophobic and coordination interactions and formed by the hierarchical self-assembly of block copolymer micelle and block comicelle precursors, can be manipulated, transformed and patterned with mediation by dynamic holographic assembly (optical tweezers). This allows the creation of new and stable soft-matter superstructures far from equilibrium. For example, individual spherical supermicelles can be optically held in close proximity and photocrosslinked through controlled coronal chemistry to generate linear oligomeric arrays. The use of optical tweezers also enables the directed deposition and immobilization of supermicelles on surfaces, allowing the precise creation of arrays of soft-matter nano-objects with potentially diverse functionality and a range of applications

Microfibres and macroscopic films from the coordination-driven hierarchical self-assembly of cylindrical micelles

Anisotropic nanoparticles prepared from block copolymers are of growing importance as building blocks for the creation of synthetic hierarchical materials. However, the assembly of these structural units is generally limited to the use of amphiphilic interactions. Here we report a simple, reversible coordination-driven hierarchical self-assembly strategy for the preparation of micron-scale fibres and macroscopic films based on monodisperse cylindrical block copolymer micelles. Coordination of Pd(0) metal centres to phosphine ligands immobilized within the soluble coronas of block copolymer micelles is found to induce intermicelle crosslinking, affording stable linear fibres comprised of micelle subunits in a staggered arrangement. The mean length of the fibres can be varied by altering the micelle concentration, reaction stoichiometry or aspect ratio of the micelle building blocks. Furthermore, the fibres aggregate on drying to form robust, self-supporting macroscopic micelle-based thin films with useful mechanical properties that are analogous to crosslinked polymer networks, but on a longer length scale

Bibliometrics of systematic reviews : analysis of citation rates and journal impact factors

Background: Systematic reviews are important for informing clinical practice and health policy. The aim of this study was to examine the bibliometrics of systematic reviews and to determine the amount of variance in citations predicted by the journal impact factor (JIF) alone and combined with several other characteristics. Methods: We conducted a bibliometric analysis of 1,261 systematic reviews published in 2008 and the citations to them in the Scopus database from 2008 to June 2012. Potential predictors of the citation impact of the reviews were examined using descriptive, univariate and multiple regression analysis. Results: The mean number of citations per review over four years was 26.5 (SD +/-29.9) or 6.6 citations per review per year. The mean JIF of the journals in which the reviews were published was 4.3 (SD +/-4.2). We found that 17% of the reviews accounted for 50% of the total citations and 1.6% of the reviews were not cited. The number of authors was correlated with the number of citations (r = 0.215, P =5.16) received citations in the bottom quartile (eight or fewer), whereas 9% of reviews published in the lowest JIF quartile (<=2.06) received citations in the top quartile (34 or more). Six percent of reviews in journals with no JIF were also in the first quartile of citations. Conclusions: The JIF predicted over half of the variation in citations to the systematic reviews. However, the distribution of citations was markedly skewed. Some reviews in journals with low JIFs were well-cited and others in higher JIF journals received relatively few citations; hence the JIF did not accurately represent the number of citations to individual systematic reviews

Fibroblast activation protein is induced by inflammation and degrades type I collagen in thin-cap fibroatheromata

Aims Collagen degradation in atherosclerotic plaques with thin fibrous caps renders them more prone to rupture. Fibroblast activation protein (FAP) plays a role in arthritis and tumour formation through its collagenase activity. However, the significance of FAP in thin-cap human fibroatheromata remains unknown. Methods and results We detected enhanced FAP expression in type IV-V human aortic atheromata (n = 12), compared with type II-III lesions (n = 9; P < 0.01) and healthy aortae (n = 8; P < 0.01) by immunostaining and western blot analyses. Fibroblast activation protein was also increased in thin-cap (<65 µm) vs. thick-cap (≥65 µm) human coronary fibroatheromata (n = 12; P < 0.01). Fibroblast activation protein was expressed by human aortic smooth muscle cells (HASMC) as shown by colocalization on immunofluorescent aortic plaque stainings (n = 10; P < 0.01) and by flow cytometry in cell culture. Although macrophages did not express FAP, macrophage burden in human aortic plaques correlated with FAP expression (n = 12; R2= 0.763; P < 0.05). Enzyme-linked immunosorbent assays showed a time- and dose-dependent up-regulation of FAP in response to human tumour necrosis factor α (TNFα) in HASMC (n = 6; P < 0.01). Moreover, supernatants from peripheral blood-derived macrophages induced FAP expression in cultured HASMC (n = 6; P < 0.01), an effect abolished by blocking TNFα (n = 6; P < 0.01). Fibroblast activation protein associated with collagen-poor regions in human coronary fibrous caps and digested type I collagen and gelatin in vitro (n = 6; P < 0.01). Zymography revealed that FAP-mediated collagenase activity was neutralized by an antibody directed against the FAP catalytic domain both in HASMC (n = 6; P < 0.01) and in fibrous caps of atherosclerotic plaques (n = 10; P < 0.01). Conclusion Fibroblast activation protein expression in HASMC is induced by macrophage-derived TNFα. Fibroblast activation protein associates with thin-cap human coronary fibroatheromata and contributes to type I collagen breakdown in fibrous cap

Fibroblast activation protein is induced by inflammation and degrades type I collagen in thin-cap fibroatheromata

Aims Collagen degradation in atherosclerotic plaques with thin fibrous caps renders them more prone to rupture. Fibroblast activation protein (FAP) plays a role in arthritis and tumour formation through its collagenase activity. However, the significance of FAP in thin-cap human fibroatheromata remains unknown. Methods and results We detected enhanced FAP expression in type IV-V human aortic atheromata (n = 12), compared with type II-III lesions (n = 9; P < 0.01) and healthy aortae (n = 8; P < 0.01) by immunostaining and western blot analyses. Fibroblast activation protein was also increased in thin-cap (<65 µm) vs. thick-cap (≥65 µm) human coronary fibroatheromata (n = 12; P < 0.01). Fibroblast activation protein was expressed by human aortic smooth muscle cells (HASMC) as shown by colocalization on immunofluorescent aortic plaque stainings (n = 10; P < 0.01) and by flow cytometry in cell culture. Although macrophages did not express FAP, macrophage burden in human aortic plaques correlated with FAP expression (n = 12; R(2)= 0.763; P < 0.05). Enzyme-linked immunosorbent assays showed a time- and dose-dependent up-regulation of FAP in response to human tumour necrosis factor α (TNFα) in HASMC (n = 6; P < 0.01). Moreover, supernatants from peripheral blood-derived macrophages induced FAP expression in cultured HASMC (n = 6; P < 0.01), an effect abolished by blocking TNFα (n = 6; P < 0.01). Fibroblast activation protein associated with collagen-poor regions in human coronary fibrous caps and digested type I collagen and gelatin in vitro (n = 6; P < 0.01). Zymography revealed that FAP-mediated collagenase activity was neutralized by an antibody directed against the FAP catalytic domain both in HASMC (n = 6; P < 0.01) and in fibrous caps of atherosclerotic plaques (n = 10; P < 0.01). Conclusion Fibroblast activation protein expression in HASMC is induced by macrophage-derived TNFα. Fibroblast activation protein associates with thin-cap human coronary fibroatheromata and contributes to type I collagen breakdown in fibrous caps

Developmental Exposure to a Commercial PBDE Mixture: Effects on Protein Networks in the Cerebellum and Hippocampus of Rats

Background: Polybrominated diphenyl ethers (PBDEs) are structurally similar to polychlorinated biphenyls (PCBs) and have both central (learning and memory deficits) and peripheral (motor dysfunction) neurotoxic effects at concentrations/doses similar to those of PCBs. The cellular and molecular mechanisms for these neurotoxic effects are not fully understood; however, several studies have shown that PBDEs affect thyroid hormones, cause oxidative stress, and disrupt Ca2+-mediated signal transduction. Changes in these signal transduction pathways can lead to differential gene regulation with subsequent changes in protein expression, which can affect the development and function of the nervous system