Exploratory study of possible resonances in the heavy meson - heavy baryon coupled-channel interactions

We use a unitary coupled-channel model to study the $\bar{D} \Lambda_c - \bar{D} \Sigma_c$ interactions. In our calculation, SU(3) flavor symmetry is applied to determine the coupling constants. Several resonant and bound states with different spin and parity are dynamically generated in the mass range of the recently observed pentaquarks. The approach is also extended to the hidden beauty sector to study the $B \Lambda_b - B \Sigma_b$ interactions. As the $b$-quark mass is heavier than the $c$-quark mass, there are more resonances observed for $B \Lambda_b - B \Sigma_b$ interactions and they are more tightly bound.Comment: 10 pages, 11 figures, updated to the published versio

Lectin affinity binding of pseudononas aeruginosa with polyacrylamide neoglycoconjugates [abstract]

The main clinical feature of cystic fibrosis (CF) is a chronic progressive lung disease caused mainly by Pseudomonas aeruginosa (PA) infection. The mechanism of bacterial invasion is not very clear. It's been shown that PA recognizing specific saccharides through lectins on the airway surface could be the very first step during invasion and infection. This project aims to conduct a comprehensive analysis of saccharides that could bind to different PA isolates from CF patients

Macrophage Uptake and Cytotoxicity of Paclitaxel Nanocrystals

Effective drug delivery remains one of the most challenging tasks in combatting cancer cells. Anti-cancer drugs such as Paclitaxel (PTX) often struggle in having a high drug effect because they are often phagocytized by macrophages in Reticuloendothelial System (RES) before reaching the cancer cells. To combat this problem, PTX was inserted in a nanocrystal, coated with non-ionic surfactant F68; it is speculated that this formulation will minimize the particle aggregation and decrease the cellular uptake in the RES, which will increase the overall efficacy of the drug in the target areas. The aim of this project was to compare the cellular uptake and the toxicity of commercially produced PTX, PTX-loaded nanocrystals and F68-PTX-loaded nanocrystals, specifically in the RES macrophages. Confocal imaging was used to visualize the cellular uptake of the nanocrystals, and SRB assay was used to measure in-vitro cytotoxicity. The imaging and the assay suggest that while both surface coated formulation and pure paclitaxel nanocrystal are uptaken by the RES macrophages, the surface coating formulation in the nanocrystal reduces the cytotoxicity in the RES. Based on the results, the formulations show the potential to improve pharmacokinetics and biodistribution of PTX. This work can be used to seek ways to reduce toxicity in RES cells and increase the drug potency in the targeting cells

Bone matrix components activate the NLRP3 inflammasome and promote osteoclast differentiation

AbstractThe NLRP3 inflammasome senses a variety of signals referred to as danger associated molecular patterns (DAMPs), including those triggered by crystalline particulates or degradation products of extracellular matrix. Since some DAMPs confer tissue-specific activation of the inflammasomes, we tested the hypothesis that bone matrix components function as DAMPs for the NLRP3 inflammasome and regulate osteoclast differentiation. Indeed, bone particles cause exuberant osteoclastogenesis in the presence of RANKL, a response that correlates with NLRP3 abundance and the state of inflammasome activation. To determine the relevance of these findings to bone homeostasis, we studied the impact of Nlrp3 deficiency on bone using pre-clinical mouse models of high bone turnover, including estrogen deficiency and sustained exposure to parathyroid hormone or RANKL. Despite comparable baseline indices of bone mass, bone loss caused by hormonal or RANKL perturbations is significantly reduced in Nlrp3 deficient than in wild type mice. Consistent with the notion that osteolysis releases DAMPs from bone matrix, pharmacologic inhibition of bone resorption by zoledronate attenuates inflammasome activation in mice. Thus, signals originating from bone matrix activate the NLRP3 inflammasome in the osteoclast lineage, and may represent a bone-restricted positive feedback mechanism that amplifies bone resorption in pathologic conditions of accelerated bone turnover.</jats:p

Impacts of China's development strategy through Chinese aid, finance, and firms in Kenya

Thesis (M.C.P.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning, 2009.Includes bibliographical references (p. 94-96).This thesis examines the differences of Chinese and Western aid implementation and its effects in Africa though the case study of Chinese aid and finance for road development in Kenya. Today, Kenya receives tangible benefits from Chinese aid, firms, and finance in road construction. Chinese aid serves as an alternative to Western donor conditionalities in Kenya helping decrease the requirements of Western funding sources. Western aid, however, may not serve as a "substitute" for Chinese aid, therefore making Chinese aid unresponsive to Kenyan interests. The instantaneous and less bureaucratic nature of Chinese aid and China's personal interest in Kenyan infrastructure lead to an increase in road construction but eliminate Kenya's voice in Chinese aid decision. Furthermore, trainings to Kenyans illustrating a "South to South" relationship are really for building China-Kenya relations and are ineffective for Kenya's human capital development. In addition, this is the first study to outline how the combination of tying of Chinese aid to Chinese firms and China's "Go Out" policy create excessive power for Chinese companies in Kenyan road development and debt financing decisions as well as marginalize Kenya's interests. China's tying of aid and the competitive advantages of Chinese firms working in Kenya crowd out domestic industry and forfeit valuable opportunities to develop local neighboring industries. Kenya needs to treat its relationship with China not just as an aid recipient but as a player in a "mutually beneficial" relationship. In order to receive more responsive and effective aid Kenya must begin to leverage its assets desired by China in order to demand a stronger voice in aid decisions.by Deborah Wei Mullin.M.C.P

Perioperative Neurocognitive Disorder: State of the Preclinical Science.

The purpose of this article is to provide a succinct summary of the different experimental approaches that have been used in preclinical postoperative cognitive dysfunction research, and an overview of the knowledge that has accrued. This is not intended to be a comprehensive review, but rather is intended to highlight how the many different approaches have contributed to our understanding of postoperative cognitive dysfunction, and to identify knowledge gaps to be filled by further research. The authors have organized this report by the level of experimental and systems complexity, starting with molecular and cellular approaches, then moving to intact invertebrates and vertebrate animal models. In addition, the authors' goal is to improve the quality and consistency of postoperative cognitive dysfunction and perioperative neurocognitive disorder research by promoting optimal study design, enhanced transparency, and "best practices" in experimental design and reporting to increase the likelihood of corroborating results. Thus, the authors conclude with general guidelines for designing, conducting and reporting perioperative neurocognitive disorder rodent research

2D Gait Skeleton Data Normalization for Quantitative Assessment of Movement Disorders from Freehand Single Camera Video Recordings

Overlapping phenotypic features between Early Onset Ataxia (EOA) and Developmental Coordination Disorder (DCD) can complicate the clinical distinction of these disorders. Clinical rating scales are a common way to quantify movement disorders but in children these scales also rely on the observer's assessment and interpretation. Despite the introduction of inertial measurement units for objective and more precise evaluation, special hardware is still required, restricting their widespread application. Gait video recordings of movement disorder patients are frequently captured in routine clinical settings, but there is presently no suitable quantitative analysis method for these recordings. Owing to advancements in computer vision technology, deep learning pose estimation techniques may soon be ready for convenient and low-cost clinical usage. This study presents a framework based on 2D video recording in the coronal plane and pose estimation for the quantitative assessment of gait in movement disorders. To allow the calculation of distance-based features, seven different methods to normalize 2D skeleton keypoint data derived from pose estimation using deep neural networks applied to freehand video recording of gait were evaluated. In our experiments, 15 children (five EOA, five DCD and five healthy controls) were asked to walk naturally while being videotaped by a single camera in 1280 × 720 resolution at 25 frames per second. The high likelihood of the prediction of keypoint locations (mean = 0.889, standard deviation = 0.02) demonstrates the potential for distance-based features derived from routine video recordings to assist in the clinical evaluation of movement in EOA and DCD. By comparison of mean absolute angle error and mean variance of distance, the normalization methods using the Euclidean (2D) distance of left shoulder and right hip, or the average distance from left shoulder to right hip and from right shoulder to left hip were found to better perform for deriving distance-based features and further quantitative assessment of movement disorders

Highly efficient transfection of human induced pluripotent stem cells using magnetic nanoparticles.

PurposeThe delivery of transgenes into human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes (hiPSC-CMs) represents an important tool in cardiac regeneration with potential for clinical applications. Gene transfection is more difficult, however, for hiPSCs and hiPSC-CMs than for somatic cells. Despite improvements in transfection and transduction, the efficiency, cytotoxicity, safety, and cost of these methods remain unsatisfactory. The objective of this study is to examine gene transfection in hiPSCs and hiPSC-CMs using magnetic nanoparticles (NPs).MethodsMagnetic NPs are unique transfection reagents that form complexes with nucleic acids by ionic interaction. The particles, loaded with nucleic acids, can be guided by a magnetic field to allow their concentration onto the surface of the cell membrane. Subsequent uptake of the loaded particles by the cells allows for high efficiency transfection of the cells with nucleic acids. We developed a new method using magnetic NPs to transfect hiPSCs and hiPSC-CMs. HiPSCs and hiPSC-CMs were cultured and analyzed using confocal microscopy, flow cytometry, and patch clamp recordings to quantify the transfection efficiency and cellular function.ResultsWe compared the transfection efficiency of hiPSCs with that of human embryonic kidney (HEK 293) cells. We observed that the average efficiency in hiPSCs was 43%±2% compared to 62%±4% in HEK 293 cells. Further analysis of the transfected hiPSCs showed that the differentiation of hiPSCs to hiPSC-CMs was not altered by NPs. Finally, robust transfection of hiPSC-CMs with an efficiency of 18%±2% was obtained.ConclusionThe difficult-to-transfect hiPSCs and hiPSC-CMs were efficiently transfected using magnetic NPs. Our study offers a novel approach for transfection of hiPSCs and hiPSC-CMs without the need for viral vector generation