78 research outputs found

    Colloidal CuFeS2 Nanocrystals: Intermediate Fe d-Band Leads to High Photothermal Conversion Efficiency

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    We describe the colloidal hot-injection synthesis of phase-pure nanocrystals (NCs) of a highly abundant mineral, chalcopyrite (CuFeS2). Absorption bands centered at around 480 and 950 nm, spanning almost the entire visible and near infrared regions, encompass their optical extinction characteristics. These peaks are ascribable to electronic transitions from the valence band (VB) to the empty intermediate band (IB), located in the fundamental gap and mainly composed of Fe 3d orbitals. Laser-irradiation (at 808 nm) of an aqueous suspension of CuFeS2 NCs exhibited significant heating, with a photothermal conversion efficiency of 49%. Such efficient heating is ascribable to the carrier relaxation within the broad IB band (owing to the indirect VB-IB gap), as corroborated by transient absorption measurements. The intense absorption and high photothermal transduction efficiency (PTE) of these NCs in the so-called biological window (650-900 nm) makes them suitable for photothermal therapy as demonstrated by tumor cell annihilation upon laser irradiation. The otherwise harmless nature of these NCs in dark conditions was confirmed by in vitro toxicity tests on two different cell lines. The presence of the deep Fe levels constituting the IB is the origin of such enhanced PTE, which can be used to design other high performing NC photothermal agents.Comment: 12 pages, Chemistry of Materials, 31-May-201

    Qualification of tumour mutational burden by targeted next-generation sequencing as a biomarker in hepatocellular carcinoma

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    Background & Aims: Tumour mutational burden (TMB) predicts improved response and survival to immunotherapy. In this pilot study, we optimized targeted next-generation sequencing (tNGS) to estimate TMB in hepatocellular carcinoma (HCC). Methods: We sequenced 48 non-paired samples (21 fresh-frozen [FF] and 27 paraffin-embedded [FFPE]), among which 11 FFPE samples were pretreated with uracil-DNA glycosylase (UDG). Thirty samples satisfied post-sequencing quality control. High/low TMB was defined by median number of mutations/Mb (Mut/Mb), across different minimum allele frequency (MAF) thresholds ( 650.05, 650.1 and 650.2). Results: Eligible patients (n\ua0=\ua029) were cirrhotic (84%) with TNM stage I-II HCC (75%). FFPE samples had higher TMB (median 958.39 vs 2.51 Mut/Mb, P\ua0\ua0T transitions at CpG sites (median 60.3% vs 9.1%, P\ua0=.002) compared to FF. UDG-treated samples had lower TMB (median 4019.92 vs 353 Mut/Mb, P\ua0=.041) and deamination counts (median 6393.5 vs 328.5, P\ua0=.041) vs untreated FFPE. At 0.2 MAF threshold with UDG treatment, median TMB was 5.48 (range 1.68-16.07) and did not correlate with salient pathologic features of HCC, including survival. Conclusion: While tNGS on fresh HCC samples appears to be the optimal source of tumour DNA, the low median TMB values observed may limit the role of TMB as a predictor of response to immunotherapy in HCC

    The effect of hot days on occupational heat stress in the manufacturing industry: implications for workers' well-being and productivity

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    Climate change is expected to exacerbate heat stress at the workplace in temperate regions, such as Slovenia. It is therefore of paramount importance to study present and future summer heat conditions and analyze the impact of heat on workers. A set of climate indices based on summer mean (Tmean) and maximum (Tmax) air temperatures, such as the number of hot days (HD: Tmax above 30 °C), and Wet Bulb Globe Temperature (WBGT) were used to account for heat conditions in Slovenia at six locations in the period 1981–2010. Observed trends (1961–2011) of Tmean and Tmax in July were positive, being larger in the eastern part of the country. Climate change projections showed an increase up to 4.5 °C for mean temperature and 35 days for HD by the end of the twenty-first century under the high emission scenario. The increase in WBGT was smaller, although sufficiently high to increase the frequency of days with a high risk of heat stress up to an average of a third of the summer days. A case study performed at a Slovenian automobile parts manufacturing plant revealed non-optimal working conditions during summer 2016 (WBGT mainly between 20 and 25 °C). A survey conducted on 400 workers revealed that 96% perceived the temperature conditions as unsuitable, and 56% experienced headaches and fatigue. Given these conditions and climate change projections, the escalating problem of heat is worrisome. The European Commission initiated a program of research within the Horizon 2020 program to develop a heat warning system for European workers and employers, which will incorporate case-specific solutions to mitigate heat stress.The work was supported by the European Union Horizon 2020 Research and Innovation Action (Project number 668786: HEATSHIELD)

    EMOGLOBINA GLICOSILATA (HbA1c) NEL CONTROLLO A LUNGO TERMINE DEL DIABETE MELLITO DEL CANE.

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    Gli autori riferiscono i risultati di indagini condotte per verificare l'affidabilità, nella specie canina, della valutazione dell'emoglobina glicosilata (HbAlc) come indice di controllo glicometabolico a lungo termine. La determinazione di HbAlc è stata effettuata in cani clinicamente sani e dia¬betici, nei quali le modificazioni di tale indice di controllo glicemico risultano statisticamente significative. IIThe authors report the results of investigations carried out to evaluate the reliability, in canine species, of the hemoglobin glycosylated (HbAlc) as a long-term glicometabolic control parameter. The HbAlc has been determined in healthy and diabetic dogs. The values of HbAlc differ signifi¬cantly in the two groups examined

    Method for controlling solubility of quantum dots

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    The present invention refers to the field of luminescent semiconductor nanocrystals (quantum dots). In particular, the present invention relates to quantum dots (QD) functionalized with ligands bearing a dithiolane group and an acid group salified with countercations, said QDs being able to solubilize in water and other polar solvents. The invention also relates to a method for the manufacturing of said quantum dots and to their possible uses and applications in biological, medical and other technical fields

    Quantum dots functionalized with photo-or redox-active species for luminescence sensing and switching

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    Semiconductor quantum dots are inorganic nanoparticles which, because of their unique size-dependent electronic properties, are of high potential interest for the construction of functional nanodevices. Photoinduced electron and energy-transfer processes between quantum dots and surface-bound molecular species offer versatile strategies to implement functionalities such as luminescence sensing and switching. In this article we discuss the general principles underlying the rational design of this kind of multicomponent species. Successively, we illustrate a few prominent examples, taken from the recent literature, of luminescent chemosensors and switches based on quantum dots derivatized with redox- or photo-active molecular species
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