57 research outputs found

    Fluorocarbon adsorption in hierarchical porous frameworks

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    Metal-organic frameworks comprise an important class of solid-state materials and have potential for many emerging applications such as energy storage, separation, catalysis and bio-medical. Here we report the adsorption behaviour of a series of fluorocarbon derivatives on a set of microporous and hierarchical mesoporous frameworks. The microporous frameworks show a saturation uptake capacity for dichlorodifluoromethane of >4 mmol g-1 at a very low relative saturation pressure (P/Po) of 0.02. In contrast, the mesoporous framework shows an exceptionally high uptake capacity reaching >14 mmol g-1 at P/Poof 0.4. Adsorption affinity in terms of mass loading and isosteric heats of adsorption is found to generally correlate with the polarizability and boiling point of the refrigerant, with dichlorodifluoromethane > chlorodifluoromethane > chlorotrifluoromethane > tetrafluoromethane > methane. These results suggest the possibility of exploiting these sorbents for separation of azeotropic mixtures of fluorocarbons and use in eco-friendly fluorocarbon-based adsorption cooling

    Unexpected role for IL-17 in protective immunity against hypervirulent Mycobacterium tuberculosis HN878 infection

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    Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB), infects one third of the world's population. Among these infections, clinical isolates belonging to the W-Beijing appear to be emerging, representing about 50% of Mtb isolates in East Asia, and about 13% of all Mtb isolates worldwide. In animal models, infection with W-Beijing strain, Mtb HN878, is considered "hypervirulent" as it results in increased mortality and causes exacerbated immunopathology in infected animals. We had previously shown the Interleukin (IL) -17 pathway is dispensable for primary immunity against infection with the lab adapted Mtb H37Rv strain. However, it is not known whether IL-17 has any role to play in protective immunity against infection with clinical Mtb isolates. We report here that lab adapted Mtb strains, such as H37Rv, or less virulent Mtb clinical isolates, such as Mtb CDC1551, do not require IL-17 for protective immunity against infection while infection with Mtb HN878 requires IL-17 for early protective immunity. Unexpectedly, Mtb HN878 induces robust production of IL-1β through a TLR-2-dependent mechanism, which supports potent IL-17 responses. We also show that the role for IL-17 in mediating protective immunity against Mtb HN878 is through IL-17 Receptor signaling in non-hematopoietic cells, mediating the induction of the chemokine, CXCL-13, which is required for localization of T cells within lung lymphoid follicles. Correct T cell localization within lymphoid follicles in the lung is required for maximal macrophage activation and Mtb control. Since IL-17 has a critical role in vaccine-induced immunity against TB, our results have far reaching implications for the design of vaccines and therapies to prevent and treat emerging Mtb strains. In addition, our data changes the existing paradigm that IL-17 is dispensable for primary immunity against Mtb infection, and instead suggests a differential role for IL-17 in early protective immunity against emerging Mtb strains. © 2014 Gopal et al

    S100A8/A9 Proteins Mediate Neutrophilic Inflammation and Lung Pathology during Tuberculosis

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    Rationale: A hallmark of pulmonary tuberculosis (TB) is the formation of granulomas. However, the immune factors that drive the formation of a protective granuloma during latent TB, and the factors that drive the formation of inflammatory granulomas during active TB, are not well defined. Objectives: The objective of this study was to identify the underlying immune mechanisms involved in formation of inflammatory granulomas seen during active TB. Methods: The immune mediators involved in inflammatory granuloma formation during TB were assessed using human samples and experimental models of Mycobacterium tuberculosis infection, using molecular and immunologic techniques. Measurements and Main Results: We demonstrate that in human patients with active TB and in nonhuman primate models of M. tuberculosis infection, neutrophils producing S100 proteins are dominant within the inflammatory lung granulomas seen during active TB. Using the mouse model of TB, we demonstrate that the exacerbated lung inflammation seen as a result of neutrophilic accumulation is dependent on S100A8/A9 proteins. S100A8/A9 proteins promote neutrophil accumulation by inducing production of proinflammatory chemokines and cytokines, and influencing leukocyte trafficking. Importantly, serum levels of S100A8/A9 proteins along with neutrophil-associated chemokines, such as keratinocyte chemoattractant, can be used as potential surrogate biomarkers to assess lung inflammation and disease severity in human TB. Conclusions: Our results thus show a major pathologic role for S100A8/A9 proteins in mediating neutrophil accumulation and inflammation associated with TB. Thus, targeting specific molecules, such as S100A8/A9 proteins, has the potential to decrease lung tissue damage without impacting protective immunity against TB

    HER2-enriched subtype and novel molecular subgroups drive aromatase inhibitor resistance and an increased risk of relapse in early ER+/HER2+ breast cancer

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    BACKGROUND: Oestrogen receptor positive/ human epidermal growth factor receptor positive (ER+/HER2+) breast cancers (BCs) are less responsive to endocrine therapy than ER+/HER2- tumours. Mechanisms underpinning the differential behaviour of ER+HER2+ tumours are poorly characterised. Our aim was to identify biomarkers of response to 2 weeks’ presurgical AI treatment in ER+/HER2+ BCs. METHODS: All available ER+/HER2+ BC baseline tumours (n=342) in the POETIC trial were gene expression profiled using BC360™ (NanoString) covering intrinsic subtypes and 46 key biological signatures. Early response to AI was assessed by changes in Ki67 expression and residual Ki67 at 2 weeks (Ki672wk). Time-To-Recurrence (TTR) was estimated using Kaplan-Meier methods and Cox models adjusted for standard clinicopathological variables. New molecular subgroups (MS) were identified using consensus clustering. FINDINGS: HER2-enriched (HER2-E) subtype BCs (44.7% of the total) showed poorer Ki67 response and higher Ki672wk (p<0.0001) than non-HER2-E BCs. High expression of ERBB2 expression, homologous recombination deficiency (HRD) and TP53 mutational score were associated with poor response and immune-related signatures with High Ki672wk. Five new MS that were associated with differential response to AI were identified. HER2-E had significantly poorer TTR compared to Luminal BCs (HR 2.55, 95% CI 1.14–5.69; p=0.0222). The new MS were independent predictors of TTR, adding significant value beyond intrinsic subtypes. INTERPRETATION: Our results show HER2-E as a standardised biomarker associated with poor response to AI and worse outcome in ER+/HER2+. HRD, TP53 mutational score and immune-tumour tolerance are predictive biomarkers for poor response to AI. Lastly, novel MS identify additional non-HER2-E tumours not responding to AI with an increased risk of relapse

    Molecular pathology of the p53-MDM2-p14 ARF pathway in soft tissue sarcomas

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    EThOS - Electronic Theses Online ServiceGBUnited Kingdo

    Who Monitors the Monitor? Bank Capital Structure and Borrower Monitoring Who Monitors the Monitor? Bank Capital Structure and Borrower Monitoring

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    Abstract The role that banks play in screening and monitoring their borrowers is well understood. However, these bank activities are costly and unobservable, thus difficult to contract upon. This introduces the possibility of shirking and leads to the question -who monitors the monitor? Financial intermediation theories posit that bank capital structure plays such a role in incentivizing banks to monitor their borrowers. Both bank debt and bank equity have been proposed in various theories as providing the discipline to induce banks to monitor. However, empirical evidence on how bank capital structure influences borrower monitoring is scant. To circumvent identification concerns with regressing (unobservable) bank monitoring on (endogenous) bank capital structure, we use variation in country-level creditor rights to capture banks&apos; need to monitor their borrowers. We develop a theoretical model in which greater ex-post protection offered to lenders (i.e., banks) during borrower bankruptcy/renegotiation reduces the bank&apos;s ex-ante incentives to monitor. This is because the greater salvage value of bank loans reduces the bank&apos;s expected loss from not monitoring. Our model also examines how banks alter their capital structures in response to changes in their country&apos;s creditor rights, and shows that the reduced demand for bank monitoring induced by stronger creditor rights induces the bank to shift its capital structure away from the source of financing that induces it to monitor. We find empirically that increases in creditor rights result in banks tilting their capital structures away from equity and towards deposits. We verify (theoretically and empirically) that these demandbased tilts in bank capital structure are not explained by supply-side effects (i.e., creditor rights make it cheaper to supply bank debt), and conclude that bank equity is a stronger source of discipline on banks than bank debt. JEL classification: G15, G21, G3

    Denosumab for treatment of bone metastases secondary to solid tumours : systematic review and network meta-analysis

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    Abstract Aim: To evaluate the evidence for denosumab for the treatment of bone metastases secondary to solid tumours and, using a network meta-analysis, indirectly compare denosumab with bisphosphonates and best supportive care. Data sources: MEDLINE (1948 to April 2011), EMBASE (1980 to March 2011), Cochrane Library (all sections) (issue 1, 2011) and Web of Science with Conference Proceedings (1970 to May 2011) and additional meeting abstracts (2010 and 2011) were searched. Study eligibility, participants and interventions: Only randomised controlled trials assessing denosumab, bisphosphonates or best supportive care in patients with bone metastases from any solid tumour were included. Synthesis: Direct evidence comparing denosumab and zoledronic acid was assessed for breast cancer, prostate cancer and other solid tumours. Denosumab was compared with pamidronate and best supportive care through a network meta-analysis for each tumour type. The primary outcomes were time to first skeletal related event (SRE) and time to first and subsequent SRE. Secondary outcomes were skeletal morbidity rate, pain, quality of life (QoL) and overall survival. Results: Denosumab was found to be more effective in delaying the time to first SRE and reducing the risk of first and subsequent SRE compared to zoledronic acid, placebo and pamidronate. In breast and prostate cancer, denosumab was effective in reducing skeletal morbidity rate compared with placebo. The lack of published data on pain and QoL meant that firm conclusions could not be made. Denosumab did not appear to have an affect on overall survival

    Dynamic Adsorption of CO<sub>2</sub>/N<sub>2</sub> on Cation-Exchanged Chabazite SSZ-13: A Breakthrough Analysis

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    Alkali-exchanged SSZ-13 adsorbents were investigated for their applicability in separating N<sub>2</sub> from CO<sub>2</sub> in flue gas streams using a dynamic breakthrough method. In contrast to IAST calculations based on equilibrium isotherms, K<sup>+</sup> exchanged SSZ-13 was found to yield the best N<sub>2</sub> productivity, comparable to Ni-MOF-74, under dynamic conditions where diffusion properties play a significant role. This was attributed to the selective, partial blockage of access to the chabazite cavities, enhancing the separation potential in a 15/85 CO<sub>2</sub>/N<sub>2</sub> binary gas mixture

    Lipocalin 2 regulates inflammation during pulmonary mycobacterial infections.

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    Pulmonary tuberculosis (TB), caused by the intracellular bacteria Mycobacterium tuberculosis, is a worldwide disease that continues to kill more than 1.5 million people every year worldwide. The accumulation of lymphocytes mediates the formation of the tubercle granuloma in the lung and is crucial for host protection against M.tuberculosis infection. However, paradoxically the tubercle granuloma is also the basis for the immunopathology associated with the disease and very little is known about the regulatory mechanisms that constrain the inflammation associated with the granulomas. Lipocalin 2 (Lcn2) is a member of the lipocalin family of proteins and binds to bacterial siderophores thereby sequestering iron required for bacterial growth. Thus far, it is not known whether Lcn2 plays a role in the inflammatory response to mycobacterial pulmonary infections. In the present study, using models of acute and chronic mycobacterial pulmonary infections, we reveal a novel role for Lcn2 in constraining T cell lymphocytic accumulation and inflammation by inhibiting inflammatory chemokines, such as CXCL9. In contrast, Lcn2 promotes neutrophil recruitment during mycobacterial pulmonary infection, by inducing G-CSF and KC in alveolar macrophages. Importantly, despite a common role for Lcn2 in regulating chemokines during mycobacterial pulmonary infections, Lcn2 deficient mice are more susceptible to acute M.bovis BCG, but not low dose M.tuberculosis pulmonary infection
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