4,650 research outputs found

    Novel components of the Toxoplasma inner membrane complex revealed by BioID.

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    UNLABELLED:The inner membrane complex (IMC) of Toxoplasma gondii is a peripheral membrane system that is composed of flattened alveolar sacs that underlie the plasma membrane, coupled to a supporting cytoskeletal network. The IMC plays important roles in parasite replication, motility, and host cell invasion. Despite these central roles in the biology of the parasite, the proteins that constitute the IMC are largely unknown. In this study, we have adapted a technique named proximity-dependent biotin identification (BioID) for use in T. gondii to identify novel components of the IMC. Using IMC proteins in both the alveoli and the cytoskeletal network as bait, we have uncovered a total of 19 new IMC proteins in both of these suborganellar compartments, two of which we functionally evaluate by gene knockout. Importantly, labeling of IMC proteins using this approach has revealed a group of proteins that localize to the sutures of the alveolar sacs that have been seen in their entirety in Toxoplasma species only by freeze fracture electron microscopy. Collectively, our study greatly expands the repertoire of known proteins in the IMC and experimentally validates BioID as a strategy for discovering novel constituents of specific cellular compartments of T. gondii. IMPORTANCE:The identification of binding partners is critical for determining protein function within cellular compartments. However, discovery of protein-protein interactions within membrane or cytoskeletal compartments is challenging, particularly for transient or unstable interactions that are often disrupted by experimental manipulation of these compartments. To circumvent these problems, we adapted an in vivo biotinylation technique called BioID for Toxoplasma species to identify binding partners and proximal proteins within native cellular environments. We used BioID to identify 19 novel proteins in the parasite IMC, an organelle consisting of fused membrane sacs and an underlying cytoskeleton, whose protein composition is largely unknown. We also demonstrate the power of BioID for targeted discovery of proteins within specific compartments, such as the IMC cytoskeleton. In addition, we uncovered a new group of proteins localizing to the alveolar sutures of the IMC. BioID promises to reveal new insights on protein constituents and interactions within cellular compartments of Toxoplasma

    Elevated glutamatergic compounds in pregenual anterior cingulate in pediatric autism spectrum disorder demonstrated by 1H MRS and 1H MRSI.

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    Recent research in autism spectrum disorder (ASD) has aroused interest in anterior cingulate cortex and in the neurometabolite glutamate. We report two studies of pregenual anterior cingulate cortex (pACC) in pediatric ASD. First, we acquired in vivo single-voxel proton magnetic resonance spectroscopy ((1)H MRS) in 8 children with ASD and 10 typically developing controls who were well matched for age, but with fewer males and higher IQ. In the ASD group in midline pACC, we found mean 17.7% elevation of glutamate + glutamine (Glx) (p<0.05) and 21.2% (p<0.001) decrement in creatine + phosphocreatine (Cr). We then performed a larger (26 subjects with ASD, 16 controls) follow-up study in samples now matched for age, gender, and IQ using proton magnetic resonance spectroscopic imaging ((1)H MRSI). Higher spatial resolution enabled bilateral pACC acquisition. Significant effects were restricted to right pACC where Glx (9.5%, p<0.05), Cr (6.7%, p<0.05), and N-acetyl-aspartate + N-acetyl-aspartyl-glutamate (10.2%, p<0.01) in the ASD sample were elevated above control. These two independent studies suggest hyperglutamatergia and other neurometabolic abnormalities in pACC in ASD, with possible right-lateralization. The hyperglutamatergic state may reflect an imbalance of excitation over inhibition in the brain as proposed in recent neurodevelopmental models of ASD

    RRx-001 in Refractory Small-Cell Lung Carcinoma: A Case Report of a Partial Response after a Third Reintroduction of Platinum Doublets.

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    RRx-001 is a pan-active, systemically nontoxic epigenetic inhibitor under investigation in advanced non-small cell lung cancer, small-cell lung cancer and high-grade neuroendocrine tumors in a Phase II clinical trial entitled TRIPLE THREAT (NCT02489903), which reexposes patients to previously effective but refractory platinum doublets after treatment with RRx-001. The purpose of this case study is first to report a partial response to carboplatin and etoposide in a patient with small-cell lung cancer pretreated with RRx-001, indicating episensitization or resensitization by epigenetic mechanisms, and second to discuss the literature related to small-cell lung cancer and episensitization

    Polariton Nanophotonics using Phase Change Materials

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    Polaritons formed by the coupling of light and material excitations such as plasmons, phonons, or excitons enable light-matter interactions at the nanoscale beyond what is currently possible with conventional optics. Recently, significant interest has been attracted by polaritons in van der Waals materials, which could lead to applications in sensing, integrated photonic circuits and detectors. However, novel techniques are required to control the propagation of polaritons at the nanoscale and to implement the first practical devices. Here we report the experimental realization of polariton refractive and meta-optics in the mid-infrared by exploiting the properties of low-loss phonon polaritons in isotopically pure hexagonal boron nitride (hBN), which allow it to interact with the surrounding dielectric environment comprising the low-loss phase change material, Ge3_3Sb2_2Te6_6 (GST). We demonstrate waveguides which confine polaritons in a 1D geometry, and refractive optical elements such as lenses and prisms for phonon polaritons in hBN, which we characterize using scanning near field optical microscopy. Furthermore, we demonstrate metalenses, which allow for polariton wavefront engineering and sub-wavelength focusing. Our method, due to its sub-diffraction and planar nature, will enable the realization of programmable miniaturized integrated optoelectronic devices, and will lay the foundation for on-demand biosensors.Comment: 15 pages, 4 figures, typos corrected in v

    Lipopolysaccharide-enhanced, Toll-like Receptor 4–dependent T Helper Cell Type 2 Responses to Inhaled Antigen

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    Allergic asthma is an inflammatory lung disease initiated and directed by T helper cells type 2 (Th2). The mechanism involved in generation of Th2 responses to inert inhaled antigens, however, is unknown. Epidemiological evidence suggests that exposure to lipopolysaccharide (LPS) or other microbial products can influence the development and severity of asthma. However, the mechanism by which LPS influences asthma pathogenesis remains undefined. Although it is known that signaling through Toll-like receptors (TLR) is required for adaptive T helper cell type 1 (Th1) responses, it is unclear if TLRs are needed for Th2 priming. Here, we report that low level inhaled LPS signaling through TLR4 is necessary to induce Th2 responses to inhaled antigens in a mouse model of allergic sensitization. The mechanism by which LPS signaling results in Th2 sensitization involves the activation of antigen-containing dendritic cells. In contrast to low levels, inhalation of high levels of LPS with antigen results in Th1 responses. These studies suggest that the level of LPS exposure can determine the type of inflammatory response generated and provide a potential mechanistic explanation of epidemiological data on endotoxin exposure and asthma prevalence

    Strategies for Addressing Chronic Absenteeism in the Post-Pandemic Era

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    Although chronic absenteeism has been an enduring concern in PK-12 schools, it has doubled since the onset of the COVID-19 pandemic. To explore strategies for addressing this issue, this MERC research and policy brief answers five questions: 1) What are trends in chronic absenteeism pre and post-pandemic?, 2) What factors contribute to chronic absenteeism and which student groups are particularly vulnerable? 3) What are the connections between chronic absenteeism and other student outcomes? 4) What strategies are effective in reducing chronic absenteeism?, and 5) What are policies at the state and school board level intended to help address chronic absenteeism? It concludes with key takeaways and recommendations for addressing chronic absenteeism in the post-pandemic era

    Addressing School Bullying Since the Onset of COVID-19: A MERC Research and Policy Brief

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    Among the challenges presented by the COVID-19 pandemic is a shift in the nature and intensity of school bullying, perhaps symptomatic of the rapid changes and stressors that PK-12 students have endured since 2020. In this MERC research and policy brief, we explore how school bullying has changed since the onset of COVID-19 as well as research-based strategies for how educators and division leaders can best respond to it. The brief answers the following questions: 1) What is the nature of school bullying since the onset of COVID-19? 2) Which students have been particularly impacted by bullying since the pandemic? 3) What are recommended strategies for preventing school bullying since the onset of COVID-19? 4) What are current policies in Virginia and MERC school divisions related to addressing bullying? 5) What are the key takeaways and enduring questions about addressing school bullying since the onset of COVID-19

    The role of leadership in implementing lean manufacturing

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    It is widely accepted that for the successful implementation of lean manufacturing, the senior management commitment is of great importance. However, the lean journey is usually a long one, and eventually management commitment creeps. Furthermore, the involvement of employees in daily improvements is also critical for the success of implementation. Lean leadership can be considered as a way of sustaining and improving the employee performance in lean production systems. In the present study, a thorough literature review is presented focusing in reviewing the principles of lean leadership and the practices that can lead in improving the employee performance. Furthermore, the characteristics and qualities of lean leader are discussed Paper originally presented at Manufacturing Systems 4.0 – Proceedings of the 50th CIRP Conference on Manufacturing Systems, held 3 – 5 May, 2017, Taichung City, Taiwan

    Structure and magnetic property of potassium intercalated pentacene: observation of superconducting phase in KxC22H14

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    We report the results from systematic investigations on the structure and magnetic properties of potassium intercalated pentacene as a function of potassium content, K x C22H14 (1  ≤  x  ≤  3). Synchrotron radiation powder x-ray diffraction technique revealed that there are two different stable phases can be obtained via potassium intercalation, namely, K1C22H14 phase and K3C22H14 phase. Structural phase transition was induced when the potassium content was increased to the nominal value x  =  3. This phase transition is accompanied by drastic change in their magnetic property, where those samples with compositions K1C22H14 shows ferromagnetic behavior and those with near K3C22H14 lead to observation of superconductivity with transition temperature, T c, of 4.5 K. It is first time that superconductivity was observed in linear oligoacenes. Both magnetization study and synchrotron radiation powder x-ray diffraction clearly indicates that the superconducting phase belong to K3C22H14 as a result of phase transition from triclinic to monoclinic structure induced by chemical doping

    Micronutrient Deficiency Independently Predicts Time to Event in Patients with Heart Failure

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    Background—Dietary micronutrient deficiencies have been shown to predict event‐free survival in other countries but have not been examined in patients with heart failure living in the United States. The purpose of this study was to determine whether number of dietary micronutrient deficiencies in patients with heart failure was associated with shorter event‐free survival, defined as a combined end point of all‐cause hospitalization and death. Methods and Results—Four‐day food diaries were collected from 246 patients with heart failure (age: 61.5±12 years; 67% male; 73% white; 45% New York Heart Association [NYHA] class III/IV) and analyzed using Nutrition Data Systems for Research. Micronutrient deficiencies were determined according to methods recommended by the Institute of Medicine. Patients were followed for 1 year to collect data on all‐cause hospitalization or death. Patients were divided according to number of dietary micronutrient deficiencies at a cut point of ≥ 7 for the high deficiency category versus \u3c 7 for the no to moderate deficiency category. In the full sample, 29.8% of patients experienced hospitalization or death during the year, including 44.3% in the high‐deficiency group and 25.1% in the no/moderate group. The difference in survival distribution was significant (log rank, P = 0.0065). In a Cox regression, micronutrient deficiency category predicted time to event with depression, NYHA classification, comorbidity burden, body mass index, calorie and sodium intake, and prescribed angiotensin‐converting enzyme inhibitors, diuretics, or β‐blockers included as covariates. Conclusions—This study provides additional convincing evidence that diet quality of patients with heart failure plays an important role in heart failure outcomes
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