913 research outputs found
Tamoxifen Decreases Renal Inflammation and Alleviates Disease Severity in Autoimmune NZB/W F1 Mice
No full textTamoxifen alleviates disease severity and decreases double negative T cells in autoimmune MRL-lpr/lpr mice
No full textDevelopment of a novel science curriculum about neural stem cells for high-school students in Hong Kong
No full textWe are a pioneer high school in Hong Kong to develop a neuroscience curriculum for scientifically gifted students (Suen et al., 2010; Suen et al., 2017). Research-based learning associated with neurodegenerative diseases (Suen et al., 2013), brain cell culture (Suen et al., 2008) and live-cell imaging microscopy (Suen et al., 2015) are highlighted in this curriculum. To further nurture high-school students to become a neuroscientist, we develop a new curriculum about neural stem cells. Public awareness in stem cell-related issues is increasing and more and more ethical concerns are raised as stem cell medicine advances. Yet, there is no well-structured curriculum about stem cell science for junior secondary school students in Hong Kong while the elective part of senior form Biology curriculum in Hong Kong contains a short chapter about stem cell therapy. In the present report, we demonstrate the two dimensions of our Neural Stem Cell Science Curriculum (NSCSC): (i) neural stem cell science lessons for all junior form students and (ii) pull-out gifted programme of neural stem cell research for scientifically gifted students. The neural stem cell science lessons are structured based on Renzulli’s enrichment triad model (Renzulli and Reis 1997) in which students will be exposed to three types of learning activities. Type-1 learning activities target concept-building tasks. Type-2 learning activities involve practical skills of the concepts established in the type-1 learning tasks. Type-3 learning activities help students apply their skills and concepts learnt in type-1 and type-2 lesson activities to solve real problems. For scientifically gifted students, they will carry out scientific research about neural stem cells. This research-based learning mode is integrated with the Purdue Three-Stage Enrichment Model in gifted education (VanTassel-Baska and Brown 2007). Some core concepts that all of our students are expected to acquire include the nature of neural stem cells, development and differentiation of neural stem cells, sources and locations of neural stem cells and potential applications of neural stem cells in medicine
Tamoxifen Alleviates Disease Severity and Decreases Double Negative T Cells in Autoimmune Mrl-Lpr/Lpr Mice
No full textPrevious study suggested that MRL-lpr/lpr mice treated with tamoxifen ( TAM) had less severe proteinuria, reduced serum titre of anti-dsDNA autoantibodies and an increased survival rate. To investigate further the regulatory mechanisms of TAM on MRL-lpr/lpr female mice, a total dose of 200 mu g per mice (5.5 mg/kg) was given every 2 weeks subcutaneously, while the control mice were injected with oil only. After being treated with TAM four times, the mice were killed and cellular functions were evaluated. The TAM-treated groups had smaller sized spleen and lymph nodes . Flow cytometric analysis of splenocytes had a significantly lower percentage of cell number of T cells and double negative T cells (CD4( -) CD8(-) T cells). There was no difference in cytokine production ( interleukin (IL)-2, IL-4, IL-5, IL-10 and interferon-gamma (IFN-gamma)) from splenocytes stimulated with concanavalin A (Con A) or cytokines (IL-6 ) secreted by peritoneal exudate cells when stimulated with lipopolysaccharide (LPS). However, IL-2 from lymph node cells was significantly higher on TAM-treated mice. Finally, splenocytes or purified T cells stimulated with anti-CD3 antibody plus cross-linking immunoglobulin G (IgG) of the TAM-treated group had higher H-3- incorporation of proliferation assay compared with that of control groups. In vitro study further demonstrated that IL-2-activated proliferation of lymph node double negative (DN) T cells can be inhibited by TAM treatment in a dose-dependent manner. Our finding demonstrated that TAM may potentially influence T cells and modulate the immune function, which offers a novel approach to explore the Feasibility of hormone therapy for autoimmune diseases
Temperature response of the ultra-high throughput mutational spectrometer
No full textThesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2005.Includes bibliographical references (p. 43-44).The Ultra-High Throughput Mutational Spectrometer is an instrument designed to separate mutant from wild type DNA through capillary electrophoresis. Since this technique uses the melting point of the molecule to distinguish between sequences of base pairs, temperature control is crucial to the success of the device. The purpose of this analysis is to characterize the temperature response of the instrument, taking into account the heat dissipated by the 10,000 capillaries in the system during electrophoresis. Analytical models, finite element analysis, and physical models were used to predict the steady state response of the system to heat generated by capillary electrophoresis. The analytical models estimated a steady state offset of 0.2 K for water at 3.3x 10Ì⁴ m³/s (20 L/min) and 1.0 K for water at 6.7x 10Ì⁵ m³/s (4.0 L/min) and predicted that the system would reach steady state within several seconds. Finite element analysis determined that the gel inside the capillaries would have a steady state offset of 0.24 K. The physical system, which simulated the Joule heating of the capillaries using an immersion heater, yielded a steady state offset of 0.24 K at 3.3x 10Ì⁴ m³/s and 0.65 K at 6.7x 10Ì⁵ m³/s, but the settling time in both cases was on the order of 500 s.(cont.) This discrepancy is due to the fact that many aspects of the physical system, including the thermal mass of the instrument, heat loss through convection, and the PID temperature controller in the circulator, were not taken into consideration in the theoretical analysis. Pressure drop and vortex shedding were also calculated for the instrument. Finite element analysis determined the pressure drop to be 18.55 Pa. Vortex shedding does not occur, because the operating conditions of this instrument are below the critical Reynolds number.by Timothy W. Suen.S.B
Analysis of global collection of group A Streptococcus genomes reveals that the majority encode a trio of M and M-like proteins
No full textThe core Mga (multiple gene activator) regulon of group A Streptococcus (GAS) contains genes encoding proteins involved in adhesion and immune evasion. While all GAS genomes contain genes for Mga and C5a peptidase, the intervening genes encoding M and M-like proteins vary between strains. The genetic make-up of the Mga regulon of GAS was characterized by utilizing a collection of 1,688 GAS genomes that are representative of the global GAS population. Sequence variations were examined with multiple alignments, and the expression of all core Mga regulon genes was examined by quantitative reverse transcription-PCR in a representative strain collection. In 85.2% of the sampled genomes, the Mga locus contained genes encoding Mga, Mrp, M, Enn, and C5a peptidase proteins. These isolates account for 53% of global infections. Only 9.1% of genomes did not contain either an mrp or an enn gene. The pairwise identity within Enn (68.6%) and Mrp (83.2%) protein sequences was higher than within M proteins (44.7%). Gene expression varied between strains tested, but high expression was recorded for all genes in at least one strain. Previous nomenclature issues were clarified with molecular gene definitions. Our findings support a shift in focus in the GAS research field to further consider the role of Mrp and Enn in virulence and vaccine development.IMPORTANCE While the GAS M protein has been the leading vaccine target for decades, the bacteria encode many other virulence factors of interest for vaccine development. In this work, we show that emm-like genes are encoded in a remarkable majority of GAS genomes and expressed at a level similar to that for the emm gene. In collaboration with the U.S. Centers for Disease Control, we developed molecular definitions of the different emm and emm-like gene families. This clarification should abrogate mistyping of strains, especially in the area of whole-genome typing. We have also updated the emm-typing collection by removing emm-like gene sequences and provided in-depth analysis of Mrp and Enn protein sequence structure and diversity
Numerical evidence for multi-scalar stars
No full textWe present a class of general relativistic soliton-like solutions composed of multiple minimally coupled, massive, real scalar fields which interact only through the gravitational field. We describe a two-parameter family of solutions we call ''''phase-shifted boson stars (parameterized by central density and phase ), which are obtained by solving the ordinary differential equations associated with boson stars and then altering the phase between the real and imaginary parts of the field. These solutions are similar to boson stars as well as the oscillating soliton stars found by Seidel and Suen [E. Seidel and W.~M. Suen, Phys. Rev. Lett. { f 66}, 1659 (1991)]; in particular, long-time numerical evolutions suggest that phase-shifted boson stars are stable. Our results indicate that scalar soliton-like solutions are perhaps more generic than has been previously though
Numerical evidence for multi-scalar stars
No full textWe present a class of general relativistic soliton-like solutions composed of multiple minimally coupled, massive, real scalar fields which interact only through the gravitational field. We describe a two-parameter family of solutions we call ''''phase-shifted boson stars (parameterized by central density and phase ), which are obtained by solving the ordinary differential equations associated with boson stars and then altering the phase between the real and imaginary parts of the field. These solutions are similar to boson stars as well as the oscillating soliton stars found by Seidel and Suen [E. Seidel and W.~M. Suen, Phys. Rev. Lett. { f 66}, 1659 (1991)]; in particular, long-time numerical evolutions suggest that phase-shifted boson stars are stable. Our results indicate that scalar soliton-like solutions are perhaps more generic than has been previously though
Factors influencing the structure of electrochemically prepared alpha-MnO2 and gamma-MnO2 phases
No full text[[abstract]]The alpha- and gamma-phases of MnO2 prepared by electrolysis of MnSO4 and KSO4 (where M = Li+, Na+, K+, Rb+, Cs+ or Mg2+) in aqueous solutions at various pH and voltage E, values under ambient conditions have been systematically studied. The structures of powdery MnO2 produced are found to depend on the radius of the W counter cation in addition to the pH and E-v conditions. In order to achieve the a-phase for MnO2 formation under neutral pH condition, the radius of counter cation must be equal to or greater than 1.41 angstrom, the size of the K+ cation. The relative concentration ratio of [MnO4-](transient)/[Mn (2+)], which is related to the pH-Ev conditions, also affects the structure of MnO2 produced with counter ions smaller than K+. For samples prepared in acidified solution with the counter ions of Li+, Na+ or Mg2+ at 2.2 V, the electrolysis products display the gamma-MnO2 phase while those prepared at 2.8 V electrolysis produce a mixture of gamma-MnO2 and alpha-MnO2 phases. Single phase of alpha-MnO2 is identified in the 5 V electrolysis products. Furthermore, the valence state of manganese was found to decrease as the applied voltage was reduced from 5.0 to 2.2 V. This implies that the lower [MnO4-](transient)[Mn2+] ratio or the less oxidative condition is responsible for the non-stoichiometric MnO2 structure with oxygen deficiency. (c) 2007 Elsevier Ltd. All rights reserved.[[note]]SC
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