Suchergebnisse

The hasty progress in smart, portable, flexible, and transparent integrated electronics and optoelectronics is currently one of the driving forces in nanoscience and nanotechnology. A promising approach is the combination of transparent conducting electrode materials (e.g., silver nanowires, AgNWs) and luminescent nanoparticles. Here, tunable electrochromic transparent devices covering a broad range of the chromatic diagram are fabricated by combining the electrical control of the heat dissipation in AgNWs networks with size-dependent thermal properties of upconverting nanoparticles (UCNPs). The electrochromic devices are based on transparent nanocomposite films of poly(methyl methacrylate) and AgNWs covered by UCNPs of different sizes and compositions. As illustrative examples, devices mixing large-sized (>70 nm) β-NaYF4:Yb,Ln and small-sized (<15 nm) NaGdF4:Yb,Ln@NaYF4 core@shell UCNPs (Ln=Tm, Er, Ce/Ho) are presented. The temperature-dependent emission of the particles is monitored by the intensity ratio of the Er3+ 2H11/2 and 4S3/2 ® 4I15/2 emission lines, while externally controlling the current flow in the AgNWs network. Moreover, by defining a new thermometric parameter involving the intensity ratio of transitions from large- and small-sized UCNPs, a relative thermal sensitivity of 5.88 % K−1 (at 339 K) is obtained; a 6-fold improvement over the values reported so far. ; This project has received funding from the European Union's Horizon 2020 FET Open programme under grant agreement No 801305 (NanoTBTech).

Luminescent nanomaterials have shown promise for thermal sensing in bio-applications, yet little is known of the role of organic coatings such as supported lipid bilayers on the thermal conductivity between the nanomaterial and its environment. Additionally, since the supported lipid bilayer mimics the cell membrane, its thermal properties are fundamentally important to understand the spatial variations of temperature and heat transfer across membranes. Herein we describe a new approach that enables direct measurement of these thermal properties using a LiYF4: Er3+ / Yb3+ upconverting nanoparticle encapsulated within a conformal supported lipid bilayer and dispersed in water as a temperature probe yielding the temperature gradient across the bilayer. The thermal conductivity of lipid bilayer was measured as a function of the temperature, being 0.20±0.02 W·m‒1·K‒1 at 300 K. For the uncapped nanoparticles dispersed in water, the temperature dependence of the thermal conductivity was also measured in the 300‒314 K range as [0.63‒0.69]±0.11 W·m‒1·K‒1. Using a lumped elements model, we calculate the directional heat transfer at each of the system interfaces, namely nanoparticle-bilayer and bilayer-nanofluid, opening a new avenue to understand the membrane biophysical properties as well as the thermal properties of organic and polymer coatings. ; This project has received funding from the European Union's Horizon 2020 FET Open programme under grant agreement No 801305 (NanoTBTech).

AbstractIntroductionPeople living with HIV (PLHIV) on antiretroviral therapy (ART) experience high rates of non‐communicable diseases (NCDs). These co‐morbidities often accumulate and older adults may suffer from multimorbidity. Multimorbidity has been associated with loss of quality of life, polypharmacy, and increased risk of frailty and mortality. Little is known of the trends or predictors NCD multimorbidity in PLHIV in low‐ and middle‐income countries.MethodsWe examined NCD multimorbidity in adult PLHIV initiating ART between 2003 and 2014 using a multi‐site, observational cohort in Brazil. NCDs included cardiovascular artery disease, hyperlipidemia (HLD), diabetes, chronic kidney disease, cirrhosis, osteoporosis, osteonecrosis, venous thromboembolism and non‐AIDS‐defining cancers. Multimorbidity was defined as the incident accumulation of two or more unique NCDs. We used Poisson regression to examine trends and Cox proportional hazard models to examine predictors of multimorbidity.ResultsOf the 6206 adults, 332 (5%) developed multimorbidity during the study period. Parallel to the ageing of the cohort, the prevalence of multimorbidity rose from 3% to 11% during the study period. Older age, female sex (adjusted hazard ratio (aHR) = 1.30 (95% confidence interval (CI) 1.03 to 1.65)) and low CD4 nadir (<100 vs. ≥200 cells/mm3 aHR = 1.52 (95% CI: 1.15 to 2.01)) at cohort entry were significantly associated with increased risk of multimorbidity. Among patients with incident multimorbidity, the most common NCDs were HLD and diabetes; however, osteoporosis was also frequent in women (16 vs. 35% of men and women with multimorbidity respectively).ConclusionsAmong adult PLHIV in Brazil, NCD multimorbidity increased from 2003 to 2014. Females and adults with low CD4 nadir were at increased risk in adjusted analyses. Further studies examining prevention, screening and management of NCDs in PLHIV in low‐ and middle‐income countries are needed.

Measurement of thermogenesis in individual cells is a remarkable challenge due to the complexity of the biochemical environment (such as pH and ionic strength) and to the rapid and yet not well-understood heat transfer mechanisms throughout the cell. Here, we present a unique system for intracellular temperature mapping in a fluorescence microscope (uncertainty of 0.2 K) using rationally designed luminescent Ln3+-bearing polymeric micellar probes (Ln = Sm, Eu) incubated in breast cancer MDA-MB468 cells. Two-dimensional (2D) thermal images recorded increasing the temperature of the cells culture medium between 296 and 304 K shows inhomogeneous intracellular temperature progressions up to ∼20 degrees and subcellular gradients of ∼5 degrees between the nucleolus and the rest of the cell, illustrating the thermogenic activity of the different organelles and highlighting the potential of this tool to study intracellular processes. ; This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020 and UIDP/50011/2020, financed by Portuguese funds through the FCT/MEC and when appropriate cofinanced by FEDER under the PT2020 Partnership Agreement. Financial support from the project (NanoHeatControl, POCI-01-0145-FEDER-031469), funded by FEDER, through POCI and by Portuguese funds (OE), through FCT/MCTES, by European Union's Horizon 2020 FET Open program under grant agreement nos. 801305 and 829162, Spanish Ministry of Science Innovation and Universities (grant no: PGC2018_095795_B_I00) and Diputación General de Aragón (E11/17R) are acknowledged. ANCN thanks SusPhotoSolutions project, CENTRO-01-0145-FEDER-000005, Portugal, for his grant. The authors acknowledge the use of Servicio General de Apoyo a la Investigación-SAI, Universidad de Zaragoza. ; Peer reviewed

IntroductionIn Brazil, the use of antiretrovirals is widespread: more than 260,000 individuals are currently undergoing treatment. We conducted a survey targeting antiretroviral‐naïve individuals who were initiating antiretroviral therapy (ART) according to local guidelines. This survey covered five Brazilian regions.MethodsThe HIV Threshold Survey methodology (HIV‐THS) of the World Health Organization was utilized, and subjects were selected from seven highly populated cities representative of all Brazilian macro‐regions. Dried blood spots (DBS) were collected on SS903 collection cards and were transported by regular mail at room temperature to a single central laboratory for genotyping.ResultsWe analysed samples from 329 individuals initiating highly active antiretroviral therapy (HAART), 39 (11.8%) of whom were harbouring transmitted drug resistance (TDR). The mean CD4+ T cell count was 253 cells/µL, and the mean viral load was 142,044 copies/mL. The regional prevalence of resistance was 17.0% in the Northeast, 12.8% in the Southeast, 10.6% in the Central region, 8.5% in the North and 8.5% in the South. The inhibitor‐specific TDR prevalence was 6.9% for nucleoside reverse transcriptase inhibitors, 4.9% for non‐nucleoside reverse transcriptase inhibitors and 3.9% for protease inhibitors; 3.6% of individuals presented resistance to more than one class of inhibitors. Overall, there were trends towards higher prevalences of subtype C towards the South and subtype F towards the North. Of the DBS samples collected, 9.3% failed to provide reliable results.DiscussionWe identified variable TDR prevalence, ranging from intermediate to high levels, among individuals in whom HIV disease progressed, thus implying that resistance testing before initiating ART could be effective in Brazil. Our results also indicate that the use of DBS might be especially valuable for providing access to testing in resource‐limited and remote settings.

AbstractIntroductionKaposi's sarcoma (KS) remains the most frequent malignancy in persons living with HIV (PWH) in Latin America. We examined KS trends and outcomes from Latin American clinical sites in the era of increased access to antiretroviral therapy (ART).MethodsCohorts in Brazil, Peru, Mexico, Honduras, Argentina and Chile contributed clinical data of PWH ≥16 years old from 2000 to 2017, excluding patients with KS diagnosed before clinic enrolment. We compared KS incidence over time using multivariable incidence rate ratios. Predictors of KS before/at or after ART initiation and of mortality after KS were examined using Cox regression.ResultsOf 25 981 PWH, 481 had incident KS, including 200 ART‐naïve and 281 ART‐treated patients. From 2000 to 2017, the incidence of KS decreased from 55.1 to 3.0 per 1000 person‐years. In models adjusting for CD4 and other factors, the relative risk for KS decreased from 2000 to 2008. Since 2010, the adjusted risk of KS increased in the periods before and ≤90 days after ART initiation but decreased >90 days after ART. In addition to low CD4 and male‐to‐male sex, KS risk after ART was associated with age and history of other AIDS‐defining illnesses. Mortality after KS (approximately 25% after five years) was not associated with either year of KS diagnosis nor timing of diagnosis relative to ART initiation.ConclusionsKS incidence in Latin America has remained stable in recent years and risk is highest before and shortly after ART initiation. Early diagnosis of HIV and ART initiation remain critical priorities in the region.

We conducted an external quality assessment of Zika virus molecular diagnostic tests in Brazil using a new Zika virus standard. Of 15 laboratories, 73% showed limited sensitivity and specificity. Viral load estimates varied significantly. Continuous quality assurance is required for adequate estimates of Zika virus-associated disease and determination of patient care. ; German Centre for Infection Research ; European Union's Horizon research and innovation program (ZIKAlliance) ; EVAg ; Charite, German Ctr Infect Res, Berlin, Germany ; Hosp Univ Prof Edgard Santos, LAPI, Salvador, BA, Brazil ; Fdn Prosangue Hemoctr Sao Paulo, Sao Paulo, Brazil ; Inst Oswaldo Cruz, Rio De Janeiro, Brazil ; Fed Univ Para, Belem, Para, Brazil ; Univ Brasilia, Brasilia, DF, Brazil ; Univ Sao Paulo, Sao Paulo, Brazil ; Fundacao Oswaldo Cruz, Pernambuco, Brazil ; Univ Fed Bahia, Salvador, BA, Brazil ; Diagnost Amer DASA, Sao Paulo, Brazil ; Hosp Israelita Albert Einstein, Sao Paulo, Brazil ; Fac Med Sao Jose do Rio Preto, Sao Jose De Rio Preto, Brazil ; Fdn Med Trop Dr Heitor Vieira Dourado, Manaus, Amazonas, Brazil ; Fundacao Oswaldo Cruz, Salvador, BA, Brazil ; Univ Fed Sao Paulo, Sao Paulo, Brazil ; Aix Marseille Univ, Marseille, France ; Assistance Publ Hop Marseille, Marseille, France ; Univ Bonn, Med Ctr, Bonn, Germany ; Robert Koch Inst, Berlin, Germany ; Univ Fed Sao Paulo, Sao Paulo, Brazil ; ZIKAlliance: 734548 ; EVAg: 653316 ; Web of Science

AbstractIntroductionIn Brazil, more than 487,450 individuals are currently undergoing antiretroviral treatment. In order to monitor the transmission of drug‐resistant strains and HIV subtype distribution in the country, this work aimed to estimate its prevalence and to characterize the nationwide pretreatment drug resistance in individuals recently diagnosed with HIV between 2013 and 2015.MethodsThe HIV threshold survey methodology (HIV‐THS, WHO) targeting antiretroviral‐naive individuals with recent HIV diagnosis was utilized, and subjects were selected from 51 highly populated cities in all five Brazilian macroregions. The HIV pol genotypic test was performed by genomic sequencing.ResultsWe analysed samples from 1568 antiretroviral‐naive individuals recently diagnosed with HIV, and the overall transmitted drug resistance (TDR) prevalence was 9.5% (150 sequences). The regional prevalence of resistance according to Brazilian geographical regions was 9.4% in the northeast, 11.2% in the southeast, 6.8% in the central region, 10.2% in the north and 8.8% in the south. The inhibitor‐specific TDR prevalence was 3.6% for nucleoside reverse transcriptase inhibitors (NRTIs), 5.8% for non‐nucleoside reverse transcriptase inhibitors (NNRTIs) and 1.6% for protease inhibitors (PIs); 1.0% of individuals presented resistance to more than one class of inhibitors. Overall, subtype B was more prevalent in every region except for the southern, where subtype C prevails.ConclusionsTo the best of our knowledge, this is the first TDR study conducted in Brazil with nationwide representative sampling. The TDR prevalence revealed a moderate rate in the five Brazilian geographical regions, although some cities presented higher TDR prevalence rates, reaching 14% in São Paulo, for example. These results further illustrate the importance of surveillance studies for designing future strategies in primary antiretroviral therapy, aiming to mitigate TDR, as well as for predicting future trends in other regions of the globe where mass antiretroviral (ARV) treatment was implemented.