207 research outputs found

    Production, characterization and testing of antibacterial PVA membranes loaded with HA-Ag3PO4 nanoparticles, produced by SC-CO2 phase inversion

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    BACKGROUND: Silver-loaded hydroxyapatite nanoparticles were incorporated into poly(vinyl alcohol) (PVA) membranes obtained by supercritical CO2 (SC-CO2) assisted phase inversion. Ag3PO4 crystals of 2.2 ± 0.6 nm were dispersed in synthesized needle-like hydroxyapatite nanoparticles (20 × 65 nm) and were uniformly deposited on the internal surfaces of the PVA membranes. Operative conditions to produce membranes by SC-CO2, PVA concentration and the effect on membrane porosity and morphology were studied. RESULTS: Solutions at 20% w/w PVA produced membranes with cellular morphology and nanoporous walls, whereas 30% and 50% w/w solutions produced nanostructured membranes. Silver ions were released from PVA membranes mainly by diffusion according to the Peppas–Sahlin model. Membranes obtained at 20% w/w PVA showed a significant E. coli inhibition at an Ag concentration of 9 ppm, reaching the minimal inhibitory concentration (MIC) and improving the bactericidal activity of the nanoparticles. CONCLUSION: A concentration of Ag3PO4 crystals of about 22 ppm was calculated as being capable of completely destroying these bacteria, reaching the minimum bactericidal concentration (MBC)

    Preparation of Neutral trans - Cis [Ru(O2CR)2P2(NN)], Cationic [Ru(O2CR)P2(NN)](O2CR) and Pincer [Ru(O2CR)(CNN)P2] (P = PPh3, P2= diphosphine) Carboxylate Complexes and their Application in the Catalytic Carbonyl Compounds Reduction

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    The diacetate complexes trans-[Ru(\u3ba1-OAc)2(PPh3)2(NN)] (NN = ethylenediamine (en) (1), 2-(aminomethyl)pyridine (ampy) (2), 2-(aminomethyl)pyrimidine (ampyrim) (3)) have been isolated in 76-88% yield by reaction of [Ru(\u3ba2-OAc)2(PPh3)2] with the corresponding nitrogen ligands. The ampy-type derivatives 2 and 3 undergo isomerization to the thermodynamically most stable cationic complexes [Ru(\u3ba1-OAc)(PPh3)2(NN)]OAc (2a and 3a) and cis-[Ru(\u3ba1-OAc)2(PPh3)2(NN)] (2b and 3b) in methanol at RT. The trans-[Ru(\u3ba1-OAc)2(P2)2] (P2 = dppm (4), dppe (5)) compounds have been synthesized from [Ru(\u3ba2-OAc)2(PPh3)2] by reaction with the suitable diphosphine in toluene at 95 \ub0C. The complex cis-[Ru(\u3ba1-OAc)2(dppm)(ampy)](6) has been obtained from [Ru(\u3ba2-OAc)2(PPh3)2] and dppm in toluene at reflux and reaction with ampy. The derivatives trans-[Ru(\u3ba1-OAc)2P2(NN)] (7-16; NN = en, ampy, ampyrim, 8-aminoquinoline; P2 = dppp, dppb, dppf, (R)-BINAP) can be easily synthesized from [Ru(\u3ba2-OAc)2(PPh3)2] with a diphosphine and treatment with the NN ligands at RT. Alternatively these compounds have been prepared from trans-[Ru(OAc)2(PPh3)2(NN)] by reaction with the diphosphine in MEK at 50 \ub0C. The use of (R)-BINAP affords trans-[Ru(\u3ba1-OAc)2((R)-BINAP)(NN)] (NN = ampy (11), ampyrim (15)) isolated as single stereoisomers. Treatment of the ampy-type complexes 8-15 with methanol at RT leads to isomerization to the cationic derivatives [Ru(\u3ba2-OAc)P2(NN)]OAc (8a-15a; NN = ampy, ampyrim; P2 = dppp, dppb, dppf, (R)-BINAP). Similarly to 2, the dipivalate trans-[Ru(\u3ba1-OPiv)2(PPh3)2(ampy)] (18) is prepared from [Ru(\u3ba2-OPiv)2(PPh3)2] (17) and ampy in CHCl3. The pincer acetate [Ru(\u3ba1-OAc)(CNNOMe)(PPh3)2] (19) has been synthesized from [Ru(\u3ba2-OAc)2(PPh3)2] and HCNNOMe ligand in 2-propanol with NEt3 at reflux. In addition, the dppb pincer complexes [Ru(\u3ba1-OAc)(CNN)(dppb)] (CNN = AMTP (20), AMBQPh (21)) have been obtained from [Ru(\u3ba2-OAc)2(PPh3)2], dppb, and HAMTP or HAMBQPh with NEt3, respectively. The acetate NN and pincer complexes are active in transfer hydrogenation with 2-propanol and hydrogenation with H2 of carbonyl compounds at S/C values of up to 10000 and with TOF values of up to 160000 h-1

    Retinoblastoma Is Characterized by a Cold, CD8+ Cell Poor, PD-L1- Microenvironment, Which Turns Into Hot, CD8+ Cell Rich, PD-L1+ After Chemotherapy

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    PURPOSE. To investigate the impact of chemotherapy (CHT) on human retinoblastoma (RB) tumor microenvironment (TME).CASES AND METHODS. Ninety-four RBs were studied, including 44 primary RBs treated by upfront surgery (Group 1) and 50 primary RBs enucleated after CHT (CHT), either intraarterial (IAC; Group 2, 33 cases) or systemic (S-CHT; Group 3, 17 cases). Conventional and multiplexed immunohistochemistry were performed to make quantitative comparisons among the three groups, for the following parameters: tumor-infiltrating inflammatory cells (TI-ICs); programmed cell death protein 1 (PD-1) positive TI-ICs; Ki67 proliferation index; gliosis; PD-1 ligand (PD-L1) protein expression; vessel number. We also correlated these TME factors with the presence of histological high-risk factors (HHRF+) and RB anaplasia grade (AG).RESULTS. After CHT, a decrease in both RB burden and Ki67 positivity was observed. In parallel, most subsets of TI-ICs, PD-1+ TI-ICs, gliosis, and PD-L1 protein expression significantly increased (P < 0.001, P = 0.02, P < 0.001, respectively). Vessel number did not significantly vary. Age, HHRFs+ and AG were significantly different between primary and chemoreduced RBs (P < 0.001, P = 0.006, P = 0.001, respectively) and were correlated with most TME factors.CONCLUSIONS. CHT modulates host antitumor immunity by reorienting the RB TME from anergic into an active, CD8+, PD-L1+ hot state. Furthermore, some clinicopathological characteristics of RB correlate with several factors of TME. Our study adds data in favor of the possibility of a new therapeutic scenario in human RB

    Prognostic role of KRAS mutations in Sardinian patients with colorectal carcinoma

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    The presence of mutations in the KRAS gene is a predictor of a poor clinical response to EGFR-targeted agents in patients affected by colorectal cancer (CRC), but its significance as a global prognostic factor remains unclear. The aim of the present study was to evaluate the impact of the KRAS mutational status on time to first metastasis (TTM) and overall survival (OS) in a cohort of Sardinian CRC patients. A total of 551 patients with metastatic CRC at the time of enrolment were included. Clinical and pathological features of the disease, including follow-up information, were obtained from medical records and cancer registry data. For mutational analysis formalin-fixed paraffin-embedded tissue samples were processed using a standard protocol. The coding sequence and splice junctions of exons 2 and 3 of the KRAS gene were screened for mutations by direct automated sequencing. Overall, 186 KRAS mutations were detected in 183/551 (33%) patients: 125 (67%) were located in codon 12, 36 (19%) in codon 13, and 18 (10%) in codon 61. The remaining mutations (7; 4%) were detected in uncommonly-affected codons. No significant correlation between KRAS mutations and gender, age, anatomical location and stage of the disease at the time of diagnosis was identified. Furthermore, no prognostic value of KRAS mutations was found considering either TTM or OS. When patients were stratified by KRAS mutational status and gender, males were significantly associated with a longer TTM. The results of the present study indicate that KRAS mutation correlated with a slower metastatic progression in males with CRC from Sardinia, irrespective of the age at diagnosis and the codon of the mutatio

    A review on the latest advances in extraction and analysis of artemisinin

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    Introduction: Artemisinin (1), a well-known natural antimalarial drug, is a sesquiterpene lactone that contains a unique peroxide bridge. Since its discovery, the amount of research into the analysis of artemisinin has increased considerably, and it has been further intensified since the Noble Prize win by Tu Youyou in the year 2015 for the discovery of artemisinin. Objective: To review published literature on the extraction and analysis of artemisinin, published during 2017-present, and to present an appraisal of those methods. Methodology: Extensive literature search was carried out which involved, but not limited to, the use of, various databases, like Web of Knowledge, PubMed and Google Scholar, and relevant published materials including published books. The keywords used, in various combinations, with artemisinin being present in all combinations, in the search were artemisinin, Artemisia annua, analysis, extraction, quantitative, qualitative and quality control. Results: During the period covered in this review, there are several methods of analysis of artemisinin have been reported, the most of which were LC-based methods. However, the use of new methods like near infrared analysis, fluorometirc analysis and molecular imprinting, and a significant increase in the use of computational tools have been observed. Mainly several methods involving supercritical fluid extraction and ultrasound-assisted extraction of artemisinin have dominated the extraction area. Conclusions: Newer analytical tools, as well as improved protocols for the known analytical tools, for qualitative and quantitative determination of artemisinin (1), have been made available by various researchers during the period covered by this review. Supercritical fluid extraction and ultrasound-assisted extraction are still the methods of choice for extraction of artemisinin

    Mathematics, capitalism and biosocial research

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    In my previous work, I criticised studies within the sociopolitical turn for disavowing a comprehension of schools as places of capitalist production. Here, I extend this critique to what is being flagged as a new turn in educational research. I am referring to biosocial research, particularly in the way it is coupled with new materialist and more than human philosophies in the work of Elizabeth de Freitas. I use elements from Marxian theory and Lacanian psychoanalysis to explore the concomitances between mathematics and capitalism, showing how both mathematics and capital need to suture the subject in order to thrive. Biosocial research epitomises this drive towards automation and totality, and, notwithstanding de Freitas’ attempts to rescue it from the logic of control, I will argue that agent-centred intentions dismiss the underlying workings of capital as a real abstraction. I do so by engaging with elements of Deleuze’s philosophy, showing how the more than human frame in which de Freitas’ biosocial research rests contradicts her own perception of how biosocial research can be rescued for inclusive purposes

    At the intersection between the subject and the political: a contribution to an ongoing discussion

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    The issue of subjectivity has recently occasioned a lively discussion in this journal opposing socioculturalism and Lacanian psychoanalysis. By confronting Luis Radford’s cultural theory with Jacques Lacan’s psychoanalysis, Tony Brown sought to show the limitations of socioculturalism. This article takes advantage of that discussion to develop a critique of Radford’s theory of objectification, taken as an exemplary sociocultural theorization of the teaching and learning of mathematics. It does so by extending the criticism made by Brown at the level of the subject, namely by showing what is lost in socioculturalism when it reduces the Hegelian notion of dialectics to a relation between constituted entities; but mostly by exploring the possibility opened by contemporary theory to posit the discussion around subjectivity in the political. While socioculturalism assumes the possibility of a synthesis between person and culture thus making education possible, it will be argued that a theory which assumes the impossibility of education is in a better position to, on the one hand, conceptualize the resistance of many towards the learning of mathematics, and on the other hand, to address the ongoing political failure in achieving the desired goal of “mathematics for all”

    Contextualising the pervasive impact of macroeconomic austerity on prison health in England: A qualitative study among international policymakers

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    Background: Prisons offer the state the opportunity to gain access to a population that is at particularly high risk of ill-health. Despite the supportive legal and policy structures surrounding prison rehabilitation, the oppressive nature of the austerity policy in England threatens its advanced improvement.Methods: Using grounded theory methodology, this is the first interdisciplinary qualitative study to explore the impact of macroeconomic austerity on prison health in England from the perspective of 29 international prison policymakers.Results: The far-reaching impact of austerity in England has established a regressive political system that shapes the societal attitude towards social issues, which has exacerbated the existing poor health of the prisoners. Austerity has undermined the notion of social collectivism, imposed a culture of acceptance among prison bureaucrats and the wider community, and normalised the devastating impacts of prison instability. These developments are evidenced by the increasing levels of suicide, violence, radicalisation and prison gangs among prisoners, as well as the imposition of long working hours and the high levels of absenteeism among prison staff.Conclusions: This study underscores an important and yet unarticulated phenomenon that despite being the fifth largest economy in the world, England’s poorest, marginalised and excluded population continues to bear the brunt of austerity. Reducing the prison population, using international obligations as minimum standards to protect prisoners’ right to health and providing greater resources would create a more positive and inclusive system, in line with England’s international and domestic commitments to the humane treatment of all people
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