Sensitive Monitoring of the Minimum Inhibitor Concentration under Real Inorganic Scaling Scenarios.

Flow assurance is a long-term challenge for oil and gas exploration as it plays a key role in designing safe and efficient operation techniques to ensure the uninterrupted transport of reservoir fluids. In this regard, the sensitive monitoring of the scale formation process is important by providing an accurate assessment of the minimum inhibitor concentration (MIC) of antiscale products. The optimum dosage of antiscale inputs is of pivotal relevance as their application at concentrations both lower and higher than MIC can imply pipeline blockages, critically hindering the entire supply chain of oil-related inputs and products to society. Using a simple and low-cost impedimetric platform, we here address the monitoring of the scale formation on stainless-steel capillaries from its early stages under real topside (ambient pressure and 60 °C) and subsea (1000 psi and 80 °C) sceneries of the oil industry. The method could continuously gauge the scale formation with a sensitivity higher than the conventional approach, i.e., the tube blocking test (TBT), which proved to be mandatory for avoiding misleading inferences on the MIC. In fact, whereas our sensor could entail accurate MICs, as confirmed by scanning electron microscopy, TBT suffered from negative deviations, with the predicted MICs being lower than the real values. Importantly, the impedance measurements were performed through a hand-held, user-friendly workstation. In this way, our method is envisioned to deliver an attractive and readily deployable platform to combat the scale formation issues because it can continuously monitor the salt precipitation from its early stages and yield the accurate determination of MIC.

Evidence of reassortment of avian influenza A (H2) viruses in Brazilian shorebirds.

Influenza A viruses of the H2 subtype represent a zoonotic and pandemic threat to humans due to a lack of widespread specific immunity. Although A(H2) viruses that circulate in wild bird reservoirs are distinct from the 1957 pandemic A(H2N2) viruses, there is concern that they could impact animal and public health. There is limited information on AIVs in Latin America, and next to nothing about H2 subtypes in Brazil. In the present study, we report the occurrence and genomic sequences of two influenza A viruses isolated from wild-caught white-rumped sandpipers (Calidris fuscicollis). One virus, identified as A(H2N1), was isolated from a bird captured in Restinga de Jurubatiba National Park (PNRJ, Rio de Janeiro), while the other, identified as A(H2N2), was isolated from a bird captured in Lagoa do Peixe National Park (PNLP, Rio Grande do Sul). DNA sequencing and phylogenetic analysis of the obtained sequences revealed that each virus belonged to distinct subtypes. Furthermore, the phylogenetic analysis indicated that the genomic sequence of the A(H2N1) virus isolated from PNRJ was most closely related to other A(H2N1) viruses isolated from North American birds. On the other hand, the A(H2N2) virus genome recovered from the PNLP-captured bird exhibited a more diverse origin, with some sequences closely related to viruses from Iceland and North America, and others showing similarity to virus sequences recovered from birds in South America. Viral genes of diverse origins were identified in one of the viruses, indicating local reassortment. This suggests that the extreme South of Brazil may serve as an environment conducive to reassortment between avian influenza virus lineages from North and South America, potentially contributing to an increase in overall viral diversity.

Ultradense Electrochemical Chips with Arrays of Nanostructured Microelectrodes to Enable Sensitive Diffusion-Limited Bioassays.

Nanostructured microelectrodes (NMEs) are an attractive alternative to yield sensitive bioassays in unprocessed samples. However, although valuable for different applications, nanoporous NMEs usually cannot boost the sensitivity of diffusion-limited analyses because of the enlarged Debye length within the nanopores, which reduces their accessibility. To circumvent this limitation, nanopore-free gold NMEs were electrodeposited from 45 µm SU-8 apertures, featuring nanoridged microspikes on a recessed surface of gold thin film while carrying interconnected crown-like and spiky structures along the edge of a SU-8 passivation layer. These structures were grown onto ultradense, vertical array chips that offer a promising strategy for translating reproducible, high-resolution, and cost-effective sensors into real-world applications. The NMEs yielded reproducible analyses, while machine learning allowed us to predict the analytical responses from NME electrodeposition data. By taking advantage of the high surface area and accessible structure of the NMEs, these structures provided a sensitivity for [Fe(CN)6]3-/4- that was 5.5× higher than that of bare WEs while also delivering a moderate antibiofouling property in undiluted human plasma. As a proof of concept, these electrodes were applied toward the fast (22 min) and simple determination of Staphylococcus aureus by monitoring the oxidation of [Fe(CN)6]4-, which acted as a cellular respiration rate redox reporter. The sensors also showed a wide dynamic range, spanning 5 orders of magnitude, and a calculated limit of detection of 0.2 CFU mL-1.

Single-Response Duplexing of Electrochemical Label-Free Biosensor from the Same Tag.

Multiplexing is a valuable strategy to boost throughput and improve clinical accuracy. Exploiting the vertical, meshed design of reproducible and low-cost ultra-dense electrochemical chips, the unprecedented single-response multiplexing of typical label-free biosensors is reported. Using a cheap, handheld one-channel workstation and a single redox probe, that is, ferro/ferricyanide, the recognition events taking place on two spatially resolved locations of the same working electrode can be tracked along a single voltammetry scan by collecting the electrochemical signatures of the probe in relation to different quasi-reference electrodes, Au (0 V) and Ag/AgCl ink (+0.2 V). This spatial isolation prevents crosstalk between the redox tags and interferences over functionalization and binding steps, representing an advantage over the existing non-spatially resolved single-response multiplex strategies. As proof of concept, peptide-tethered immunosensors are demonstrated to provide the duplex detection of COVID-19 antibodies, thereby doubling the throughput while achieving 100% accuracy in serum samples. The approach is envisioned to enable broad applications in high-throughput and multi-analyte platforms, as it can be tailored to other biosensing devices and formats.

In vitro miltefosine and amphotericin B susceptibility of strains and clinical isolates of Leishmania species endemic in Brazil that cause tegumentary leishmaniasis.

Tegumentary leishmaniasis encompasses a spectrum of clinical manifestations caused by the parasitic protozoa of the genus Leishmania. In Brazil, there are at least seven Leishmania species that are endemic and responsible for this set of clinical manifestations of the disease. Current treatment is limited to a restricted number of drugs that in general have several drawbacks including parenteral use, toxicity, and severe side effects. Amphotericin B is considered a second-line drug for tegumentary leishmaniasis in Brazil, while miltefosine was recently approved for clinical use in the treatment of this disease. In this study, we investigated the in vitro susceptibility of Leishmania strains representative of the species endemic to Brazil, as well as a panel of thirteen clinical isolates of tegumentary leishmaniasis, to both amphotericin B and miltefosine. A moderate variation in the susceptibility to both drugs was found, where the EC50 values varied from 11.43 to 52.67 µM for miltefosine and from 12.89 to 62.36 nM for amphotericin B in promastigotes, while for the intracellular amastigotes, values ranged from 1.08 to 9.60 µM and from 1.69 to 22.71 nM for miltefosine and amphotericin B respectively. Furthermore, the clinical isolates and strains of the subgenus Viannia were evaluated for the presence of Leishmania RNA virus 1 (LRV1), as this is an important factor associated with disease severity and treatment outcome. These findings provide a preclinical dataset of the activity of these drugs against the causative species of tegumentary leishmaniasis in Brazil.

Real-Time and In Situ Monitoring of the Synthesis of Silica Nanoparticles.

The real-time and in situ monitoring of the synthesis of nanomaterials (NMs) remains a challenging task, which is of pivotal importance by assisting fundamental studies (e.g., synthesis kinetics and colloidal phenomena) and providing optimized quality control. In fact, the lack of reproducibility in the synthesis of NMs is a bottleneck against the translation of nanotechnologies into the market toward daily practice. Here, we address an impedimetric millifluidic sensor with data processing by machine learning (ML) as a sensing platform to monitor silica nanoparticles (SiO2NPs) over a 24 h synthesis from a single measurement. The SiO2NPs were selected as a model NM because of their extensive applications. Impressively, simple ML-fitted descriptors were capable of overcoming interferences derived from SiO2NP adsorption over the signals of polarizable Au interdigitate electrodes to assure the determination of the size and concentration of nanoparticles over synthesis while meeting the trade-off between accuracy and speed/simplicity of computation. The root-mean-square errors were calculated as ∼2.0 nm (size) and 2.6 × 1010 nanoparticles mL-1 (concentration). Further, the robustness of the ML size descriptor was successfully challenged in data obtained along independent syntheses using different devices, with the global average accuracy being 103.7 ± 1.9%. Our work advances the developments required to transform a closed flow system basically encompassing the reactional flask and an impedimetric sensor into a scalable and user-friendly platform to assess the in situ synthesis of SiO2NPs. Since the sensor presents a universal response principle, the method is expected to enable the monitoring of other NMs. Such a platform may help to pave the way for translating "sense-act" systems into practice use in nanotechnology.

Fast and efficient electrochemical thinning of ultra-large supported and free-standing MoS2 layers on gold surfaces.

Molybdenum disulfide (MoS2) is a very promising layered material for electrical, optical, and electrochemical applications because of its unique and outstanding properties. To unlock its full potential, among different preparation routes, electrochemistry has gain interest due to its simple, fast, scalable and simple instrumentation. However, obtaining large-area monolayer MoS2 that will enable the fabrication of novel electronic and electrochemical devices is still challenging. In this work, we reported a simple and fast electrochemical thinning process that results in ultra-large MoS2 down to monolayer on Au surfaces. The high affinity of MoS2 by Au surfaces enables the removal of bulk layers while preserving the first layer attached to the electrode. With a proper choice of the applied potential, more than 90% of the bulk regions can be removed from large-area MoS2 crystals, as confirmed by atomic force microscopy, photoluminescence, and Raman spectroscopy. We further address a set of contributions that are helpful to elucidate the features of MoS2, namely, the hyphenation of electrochemistry and optical microscopy for real-time observation of the thinning process that was revealed to occur from the edges to the center of the flake, an image treatment to estimate the thinning area and thinning rate, and the preparation of free-standing MoS2 layers by electrochemically thinning bulk flakes on microhole-structured Ni/Au meshes.

Biocompatible Wearable Electrodes on Leaves toward the On-Site Monitoring of Water Loss from Plants.

Impedimetric wearable sensors are a promising strategy for determining the loss of water content (LWC) from leaves because they can afford on-site and nondestructive quantification of cellular water from a single measurement. Because the water content is a key marker of leaf health, monitoring of the LWC can lend key insights into daily practice in precision agriculture, toxicity studies, and the development of agricultural inputs. Ongoing challenges with this monitoring are the on-leaf adhesion, compatibility, scalability, and reproducibility of the electrodes, especially when subjected to long-term measurements. This paper introduces a set of sensing material, technological, and data processing solutions that overwhelm such obstacles. Mass-production-suitable electrodes consisting of stand-alone Ni films obtained by well-established microfabrication methods or ecofriendly pyrolyzed paper enabled reproducible determination of the LWC from soy leaves with optimized sensibilities of 27.0 (Ni) and 17.5 kΩ %-1 (paper). The freestanding design of the Ni electrodes was further key to delivering high on-leaf adhesion and long-term compatibility. Their impedances remained unchanged under the action of wind at velocities of up to 2.00 m s-1, whereas X-ray nanoprobe fluorescence assays allowed us to confirm the Ni sensor compatibility by the monitoring of the soy leaf health in an electrode-exposed area. Both electrodes operated through direct transfer of the conductive materials on hairy soy leaves using an ordinary adhesive tape. We used a hand-held and low-power potentiostat with wireless connection to a smartphone to determine the LWC over 24 h. Impressively, a machine-learning model was able to convert the sensing responses into a simple mathematical equation that gauged the impairments on the water content at two temperatures (30 and 20 °C) with reduced root-mean-square errors (0.1% up to 0.3%). These data suggest broad applicability of the platform by enabling direct determination of the LWC from leaves even at variable temperatures. Overall, our findings may help to pave the way for translating "sense-act" technologies into practice toward the on-site and remote investigation of plant drought stress. These platforms can provide key information for aiding efficient data-driven management and guiding decision-making steps.

Using machine learning and an electronic tongue for discriminating saliva samples from oral cavity cancer patients and healthy individuals.

The diagnosis of cancer and other diseases using data from non-specific sensors - such as the electronic tongues (e-tongues) - is challenging owing to the lack of selectivity, in addition to the variability of biological samples. In this study, we demonstrate that impedance data obtained with an e-tongue in saliva samples can be used to diagnose cancer in the mouth. Data taken with a single-response microfluidic e-tongue applied to the saliva of 27 individuals were treated with multidimensional projection techniques and non-supervised and supervised machine learning algorithms. The distinction between healthy individuals and patients with cancer on the floor of mouth or oral cavity could only be made with supervised learning. Accuracy above 80% was obtained for the binary classification (YES or NO for cancer) using a Support Vector Machine (SVM) with radial basis function kernel and Random Forest. In the classification considering the type of cancer, the accuracy dropped to ca. 70%. The accuracy tended to increase when clinical information such as alcohol consumption was used in conjunction with the e-tongue data. With the random forest algorithm, the rules to explain the diagnosis could be identified using the concept of Multidimensional Calibration Space. Since the training of the machine learning algorithms is believed to be more efficient when the data of a larger number of patients are employed, the approach presented here is promising for computer-assisted diagnosis.

Development of a sticker sealed microfluidic device for in situ analytical measurements using synchrotron radiation.

Shedding synchrotron light on microfluidic systems, exploring several contrasts in situ/operando at the nanoscale, like X-ray fluorescence, diffraction, luminescence, and absorption, has the potential to reveal new properties and functionalities of materials across diverse areas, such as green energy, photonics, and nanomedicine. In this work, we present the micro-fabrication and characterization of a multifunctional polyester/glass sealed microfluidic device well-suited to combine with analytical X-ray techniques. The device consists of smooth microchannels patterned on glass, where three gold electrodes are deposited into the channels to serve in situ electrochemistry analysis or standard electrical measurements. It has been efficiently sealed through an ultraviolet-sensitive sticker-like layer based on a polyester film, and The burst pressure determined by pumping water through the microchannel(up to 0.22 MPa). Overall, the device has demonstrated exquisite chemical resistance to organic solvents, and its efficiency in the presence of biological samples (proteins) is remarkable. The device potentialities, and its high transparency to X-rays, have been demonstrated by taking advantage of the X-ray nanoprobe Carnaúba/Sirius/LNLS, by obtaining 2D X-ray nanofluorescence maps on the microchannel filled with water and after an electrochemical nucleation reaction. To wrap up, the microfluidic device characterized here has the potential to be employed in standard laboratory experiments as well as in in situ and in vivo analytical experiments using a wide electromagnetic window, from infrared to X-rays, which could serve experiments in many branches of science.

Alcohol-Triggered Capillarity through Porous Pyrolyzed Paper-Based Electrodes Enables Ultrasensitive Electrochemical Detection of Phosphate.

The sensing field has shed light on an urgent necessity for field-deployable, user-friendly, sensitive, and scalable platforms that are able to translate solutions into the real world. Here, we attempt to meet these requests by addressing a simple, low-cost, and fast electrochemical approach to provide sensitive assays that consist of dropping a small volume (0.5 µL) of off-the-shelf alcohols on pyrolyzed paper-based electrodes before adding the sample (150 µL). This method was applied in the detection of phosphate after the formation of the phosphomolybdate complex (250-860 nm in size). Prior drops of isopropanol allow for the fast penetration of the sample through pores of this hydrophobic paper, delivering hindrance-free redox reactions across increasing active areas and ultimately improving the detection performance. The sensitivity (-1.9 10-6 mA cm-2 ppb-1) and limit of detection (1.1 ppb) were improved, respectively, by factors of 33 and 99 over the data achieved without the addition of isopropanol, listing among the lowest values when compared with those results reported in the literature for phosphate (expressed in terms of the concentration of phosphorus). The approach enabled the quantification of this analyte in real samples with accuracies ranging from 87 to 103%. Furthermore, preliminary measurements demonstrated the successful performance of the electrodes with prior addition of other widely used alcohols, that is, methanol and ethanol. These results may extend the applicability of the method. In special, the scalability and eco-friendly character of the electrode fabrication combined with the sensitivity and simplicity of the analyses make the developed platform a promising alternative that may help to pave the way for a new generation of disposable sensors toward the daily monitoring of phosphate in water samples, thus contributing to prevent ecological side effects.

Bifunctional Metal Meshes Acting as a Semipermeable Membrane and Electrode for Sensitive Electrochemical Determination of Volatile Compounds.

The monitoring of toxic inorganic gases and volatile organic compounds has brought the development of field-deployable, sensitive, and scalable sensors into focus. Here, we attempted to meet these requirements by using concurrently microhole-structured meshes as (i) a membrane for the gas diffusion extraction of an analyte from a donor sample and (ii) an electrode for the sensitive electrochemical determination of this target with the receptor electrolyte at rest. We used two types of meshes with complementary benefits, i.e., Ni mesh fabricated by robust, scalable, and well-established methods for manufacturing specific designs and stainless steel wire mesh (SSWM), which is commercially available at a low cost. The diffusion of gas (from a donor) was conducted in headspace mode, thus minimizing issues related to mesh fouling. When compared with the conventional polytetrafluoroethylene (PTFE) membrane, both the meshes (40 µm hole diameter) led to a higher amount of vapor collected into the electrolyte for subsequent detection. This inedited fashion produced a kind of reverse diffusion of the analyte dissolved into the electrolyte (receptor), i.e., from the electrode to bulk, which further enabled highly sensitive analyses. Using Ni mesh coated with Ni(OH)2 nanoparticles, the limit of detection reached for ethanol was 24-fold lower than the data attained by a platform with a PTFE membrane and placement of the electrode into electrolyte bulk. This system was applied in the determination of ethanol in complex samples related to the production of ethanol biofuel. It is noteworthy that a simple equation fitted by machine learning was able to provide accurate assays (accuracies from 97 to 102%) by overcoming matrix effect-related interferences on detection performance. Furthermore, preliminary measurements demonstrated the successful coating of the meshes with gold films as an alternative raw electrode material and the monitoring of HCl utilizing Au-coated SSWMs. These strategies extend the applicability of the platform that may help to develop valuable volatile sensing solutions.

Avaliação do desempenho de teste rápido e de dois imunoensaios automatizados para Sars-CoV-2 / Performance evaluation of a Sars-CoV-2 rapid test and two automated immunoassays

Introdução: Em função da urgência e demanda de uma resposta à pandemia do novo coronavírus (Covid-19), vários testes de detecção de anticorpos para a síndrome respiratória aguda grave do coronavírus 2 (Sars-CoV-2) têm sido desenvolvidos. Objetivo: Este estudo teve como objetivo avaliar o desempenho do teste rápido utilizado em um inquérito epidemiológico para Sars-CoV-2 em comparação com outros ensaios sorológicos. Métodos: Foram avaliadas 86 amostras de soro em três ensaios sorológicos: um imunoensaio de fluxo lateral ­ Wondfo Sars-CoV-2 Antibody Test (TRW) ­ e dois imunoensaios de quimioluminescência: Elecsys anti-Sars-CoV-2 (ECLIA) e Sars-CoV-2 IgG (CMIA-IgG). Resultados: As sensibilidades diagnósticas estimadas dos testes sorológicos na avaliação dessas amostras foram: TRW 59% [95% intervalo de confiança (IC) 43,4%-72,9%], ECLIA 66,7% (51%-79,4%) e CMIA-IgG 61,5% (47,1%-73%). Enquanto isso, a especificidade diagnóstica estimada para TRW foi 78,7% (95% CI 65,1%-88%), ECLIA 72,3% (58,2%-83,1%) e CMIA-IgG 76,6% (74%-95,5%). Os valores de sensibilidade e especificidade foram inferiores aos afirmados pelos fabricantes. Embora 16,2% (14/86) dos resultados tenham sido discordantes entre os três ensaios serológicos para Sars-CoV-2, o grau de concordância pelo índice Kappa foi adequado: TRW/CMIA-IgG [0,757 (95% IC 0,615-0,899)], TRW/ECLIA [0,715 (0,565-0,864)] e ECLIA/CMIA-IgG [0,858 (0,748-0,968)]. Conclusão: O teste sorológico pode ser uma ferramenta diagnóstica útil, o que reforça sua avaliação criteriosa, bem como o momento correto de sua utilização. (AU)

Introduction: Due to urgency and demand of a response to the Covid-19 pandemic, numerous Sars-CoV-2 immunoassays have been rapidly developed. Objective: This study aimed at assessing the performance of rapid Sars-CoV-2 antibody test in comparison to high-throughput serological assays. Methods: A total of 86 serum samples were evaluated in the three assays: a lateral flow immunoassay ­ Wondfo Sars-CoV-2 Antibody Test (WRT) ­ and two chemiluminescence immunoassays: Elecsys Anti-Sars-CoV-2 (ECLIA), and Sars-CoV-2 IgG (CMIA-IgG). Results: The estimated diagnostic sensitivities of serological tests in the evaluation of serum samples from the epidemiological survey were: WRT 59.0% [95% confidence interval (CI) 43.4%-72.9%], ECLIA 66.7% (51%-79.4%), and CMIA-IgG 61.5% (47.1%-73%). Meanwhile, the estimated diagnostic specificity was for WRT 78.7% (95% CI 65.1%-88%), ECLIA 72.3% (58.2%-83.1%), and CMIA-IgG 76.6% (74%-95.5%). The sensitivity and specificity values were lower than manufacturers' claimed. Although 16.2% (14/86) of serological results were discordant among the three Sars-CoV-2 serological assays, the degree of agreement by the kappa index was adequate: WRT/CMIA-IgG [0.757 (95% CI 0.615-0.899)], WRT/ECLIA [0.715 (0.565-0.864)], and ECLIA/CMIA-IgG [0.858 (0.748-0.968)]. Conclusion: The serological testing may be a useful diagnostic tool, which reinforces its careful evaluation, and, as well as the correct time to use it. (AU)

3D micromixer for nanoliposome synthesis: a promising advance in high mass productivity.

This paper addresses an important breakthrough in the high mass production of liposomes by microfluidics technology. We investigated the synthesis of liposomes using a high flow rate microfluidic device (HFR-MD) with a 3D-twisted cross-sectional microchannel to favor chaotic advection. A simple construction scaffold technique was used to manufacture the HFR-MD. The synthesis of liposomes combined the effects of high flow and high concentration of lipids, resulting in high mass productivity (2.27 g of lipid per h) which, to our knowledge, has never been registered by only one microdevice. We assessed the effects of the flow rate ratio (FRR), total flow rate (TFR), and lipid concentration on the liposome physicochemical properties. HFR-MD liposomes were monodisperse (0.074) with a size around 100 nm under the condition of an FRR of 1 (50% v/v ethanol) and TFR of 5 ml min-1 (expandable to 10 ml min-1). We demonstrated that the mixing conditions are not the only parameter controlling liposome synthesis using experimental and computational fluid dynamics analysis. A vacuum concentrator was used for ethanol removal, and there is no further modification after processing in accordance with the structural (SAXS) and morphological (cryo-TEM) analysis. Hence, the HFR-MD can be used to prepare nanoliposomes. It emerges as an innovative tool with high mass production.

Susceptibility to paromomycin in clinical isolates and reference strains of Leishmania species responsible for tegumentary leishmaniasis in Brazil.

Treatment of tegumentary leishmaniasis in Brazil is limited to pentavalent antimonial, amphotericin B and pentamidine. These drugs, administered parenterally, cause several side effects and have a varied clinical response, depending on the species of Leishmania. Urgent expansion of the therapeutic arsenal against the disease is therefore necessary. Paromomycin is an aminoglycoside antibiotic that has already been approved for the treatment of visceral leishmaniasis in Southeast Asia. Here, we provide an in vitro evaluation of the activity of paromomycin in fifteen clinical isolates from patients with tegumentary leishmaniasis at a reference center for the treatment of the disease. Furthermore, the in vitro susceptibility to this drug in reference strains of Leishmania species that are endemic in Brazil has also been evaluated. Among the clinical isolates, nine were typed as Leishmania (Viannia) braziliensis, five as L. (Leishmania) amazonensis and one as L. (V.) guyanensis. Although never exposed to paromomycin, we found variable susceptibility among these isolates and reference strains in promastigotes and intracellular amastigotes, with the drug being more active in the amastigote form of the parasite. This study provides a preclinical dataset that is useful for the evaluation of paromomycin in the treatment of tegumentary leishmaniasis caused by species that are endemic in Brazil.

Quantification of myocardial flow reserve using a gamma camera with solid-state cadmium-zinc-telluride detectors: Relation to angiographic coronary artery disease.

BACKGROUND: Previous studies have suggested using gamma cameras with cadmium-zinc-telluride (CZT) detectors to quantify myocardial blood flow (MBF) and flow reserve (MFR). In this study, we aimed to evaluate the feasibility and accuracy of MFR quantification using a CZT camera compared to coronary angiography. METHODS: Forty-one participants referred for coronary angiography underwent a rest/stress one-day myocardial perfusion imaging protocol using a CZT gamma camera. Rest and stress dynamic phases were followed by acquisition of traditional perfusion images and time-activity curves were generated. Angiographic and perfusion results were compared to MFR. RESULTS: Patients with abnormal perfusion presented reduced MFR (2.01 [1.48-2.77] vs. 2.94 [2.38-3.64], P = 0.002), and reduced stress MBF. Patients with high-risk CAD had lower global MFR compared to patients without obstructive disease (1.99 [1.22-2.84] vs. 2.89 [2.22-3.58], P = 0.026). Obstructed vessels showed lower regional MFR when compared to non-obstructed (1.81 [1.19-2.67] vs. 2.75 [2.13-3.42], P < 0.001). A regional MFR of 2.2 provided a sensitivity of 63.2% and specificity of 74.1% to identify an obstructive lesion in the corresponding artery. CONCLUSION: In patients undergoing invasive coronary angiography for the evaluation of CAD, quantifying MBF and MFR in a CZT gamma camera is feasible and reflects underlying disease. In these patients, reduced regional MFR suggests the presence of obstructive lesion(s).

Performance evaluation of a Sars-CoV-2 rapid test and two automated immunoassays / Avaliação do desempenho de teste rápido e de dois imunoensaios automatizados para Sars-CoV-2

ABSTRACT Introduction: Due to urgency and demand of a response to the Covid-19 pandemic, numerous Sars-CoV-2 immunoassays have been rapidly developed. Objective: This study aimed at assessing the performance of rapid Sars-CoV-2 antibody test in comparison to high-throughput serological assays. Methods: A total of 86 serum samples were evaluated in the three assays: a lateral flow immunoassay - Wondfo Sars-CoV-2 Antibody Test (WRT) - and two chemiluminescence immunoassays: Elecsys Anti-Sars-CoV-2 (ECLIA), and Sars-CoV-2 IgG (CMIA-IgG). Results: The estimated diagnostic sensitivities of serological tests in the evaluation of serum samples from the epidemiological survey were: WRT 59% [95% confidence interval (CI) 43.4%-72.9%], ECLIA 66.7% (51%-79.4%), and CMIA-IgG 61.5% (47.1%-73%). Meanwhile, the estimated diagnostic specificity was for WRT 78.7% (95% CI 65.1%-88%), ECLIA 72.3% (58.2%-83.1%), and CMIA-IgG 76.6% (74%-95.5%). The sensitivity and specificity values were lower than manufacturers' claimed. Although 16.2% (14/86) of serological results were discordant among the three Sars-CoV-2 serological assays, the degree of agreement by the kappa index was adequate: WRT/CMIA-IgG [0.757 (95% CI 0.615-0.899)], WRT/ECLIA [0.715 (0.565-0.864)], and ECLIA/CMIA-IgG [0.858 (0.748-0.968)]. Conclusion: The serological testing may be a useful diagnostic tool, which reinforces its careful evaluation, and, as well as the correct time to use it.

RESUMEN Introducción: Debido a la urgencia y la demanda de una respuesta a la pandemia de Covid-19, se han desarrollado rápidamente numerosos inmunoensayos del Sars-CoV-2. Objetivo: Este estudio tuvo como objetivo evaluar el rendimiento de la prueba rápida de anticuerpos contra el Sars-CoV-2 en comparación con los ensayos serológicos de alto rendimiento. Métodos: Se evaluaron un total de 86 muestras de suero en los tres ensayos: un inmunoensayo de flujo lateral - Wondfo Sars-CoV-2 Antibody Test (TRW) - y dos inmunoensayos de quimioluminiscencia: Elecsys Anti-Sars-CoV-2 (ECLIA) y Sars-CoV-2 IgG (CMIA-IgG). Resultados: Las sensibilidades diagnósticas estimadas de las pruebas serológicas en la evaluación de muestras de suero de la encuesta epidemiológica fueron: WRT 59% [intervalo de confianza (IC) del 95%: 43,4%-72,9%], ECLIA 66,7% (51%-79,4%) y CMIA-IgG 61,5% (47,1%-73%). Mientras tanto, la especificidad diagnóstica estimada fue para WRT 78,7% (95% CI 65,1%-88%), ECLIA 72,3% (58,2%-83,1%) y CMIA-IgG 76,6% (74%-95,5%). Los valores de sensibilidad y especificidad fueron más bajos que los declarados por los fabricantes. Aunque el 16,2% (14/86) de los resultados fueron discordantes entre los tres ensayos serológicos del Sars-CoV-2, el grado de concordancia del índice kappa fue adecuado: WRT/CMIA-IgG [0,757 (IC del 95%: 0,615-0,899)], WRT/ECLIA [0,715 (0,565-0,864)] y ECLIA/CMIA-IgG [0,858 (0,748-0,968)]. Conclusión: La prueba serológica puede ser una herramienta diagnóstica útil, lo que refuerza su evaluación cuidadosa, así como el momento adecuado para usarla.

RESUMO Introdução: Em função da urgência e demanda de uma resposta à pandemia do novo coronavírus (Covid-19), vários testes de detecção de anticorpos para a síndrome respiratória aguda grave do coronavírus 2 (Sars-CoV-2) têm sido desenvolvidos. Objetivo: Este estudo teve como objetivo avaliar o desempenho do teste rápido utilizado em um inquérito epidemiológico para Sars-CoV-2 em comparação com outros ensaios sorológicos. Métodos: Foram avaliadas 86 amostras de soro em três ensaios sorológicos: um imunoensaio de fluxo lateral - Wondfo Sars-CoV-2 Antibody Test (TRW) - e dois imunoensaios de quimioluminescência: Elecsys anti-Sars-CoV-2 (ECLIA) e Sars-CoV-2 IgG (CMIA-IgG). Resultados: As sensibilidades diagnósticas estimadas dos testes sorológicos na avaliação dessas amostras foram: TRW 59% [95% intervalo de confiança (IC) 43,4%-72,9%], ECLIA 66,7% (51%-79,4%) e CMIA-IgG 61,5% (47,1%-73%). Enquanto isso, a especificidade diagnóstica estimada para TRW foi 78,7% (95% CI 65,1%-88%), ECLIA 72,3% (58,2%-83,1%) e CMIA-IgG 76,6% (74%-95,5%). Os valores de sensibilidade e especificidade foram inferiores aos afirmados pelos fabricantes. Embora 16,2% (14/86) dos resultados tenham sido discordantes entre os três ensaios serológicos para Sars-CoV-2, o grau de concordância pelo índice Kappa foi adequado: TRW/CMIA-IgG [0,757 (95% IC 0,615-0,899)], TRW/ECLIA [0,715 (0,565-0,864)] e ECLIA/CMIA-IgG [0,858 (0,748-0,968)]. Conclusão: O teste sorológico pode ser uma ferramenta diagnóstica útil, o que reforça sua avaliação criteriosa, bem como o momento correto de sua utilização.

Activity of paromomycin against Leishmania amazonensis: Direct correlation between susceptibility in vitro and the treatment outcome in vivo.

Paromomycin is an aminoglycoside antibiotic approved in 2006 for the treatment of visceral leishmaniasis caused by Leishmania donovani in Southeast Asia. Although this drug is not approved for the treatment of visceral and cutaneous leishmaniasis in Brazil, it is urgent and necessary to evaluate the potential of this drug as alternative for the treatment against species responsible for these clinical forms of the disease. In Brazil, Leishmania amazonensis is responsible for cutaneous and diffuse cutaneous leishmaniasis. The diffuse cutaneous form of the disease is difficult to treat and frequent relapses are reported, mainly when the treatment is interrupted. Here, we evaluated paromomycin susceptibility in vitro of a L. amazonensis clinical isolate from a patient with cutaneous leishmaniasis and the reference strain L. amazonensis M2269, as well as its in vivo efficacy in a murine experimental model. Although never exposed to paromomycin, a significant differential susceptibility between these two lines was found. Paromomycin was highly active in vitro against the clinical isolate in both forms of the parasite, while its activity against the reference strain was less active. In vivo studies in mice infected with each one of these lines demonstrated that paromomycin reduces lesion size and parasite burden and a direct correlation between the susceptibility in vitro and the effectiveness of this drug in vivo was found. Our findings indicate that paromomycin efficacy in vivo is dependent on intrinsic susceptibility of the parasite. Beyond that, this study contributes for the evaluation of the potential use of paromomycin in chemotherapy of cutaneous leishmaniasis in Brazil caused by L. amazonensis.

Tribute to Theodor Kocher: Far Beyond an Anatomical Reference

We know Kocher's name as an anatomical reference in neurosurgery. In fact, Theodor Kocher was a Swiss general surgeon, and his contributions were such that Kocher was honored in 1909 with the Nobel Prize in Medicine and Physiology, and he was the first surgeon to receive this honor. Kocher participated in the initial scientific phase of medicine, livingwith names that are in history, as well as him; Langenbeck and Virchow, Lucke, Billroth, Horsley, Lister, Halstedt, Pasteur, Osler, Lawson Tait, Verneuil, and a long list and other icons of the time. The present account rescues the many important facets and contributions of the Swiss surgeonTheodor Kocher, and his relationship with several of them. Kocher's memory, surgical instruments and literary production are preserved in a small wing of the University of Bern. The present article highlights how intense Kocher's dedication to the medical field was.

Enhanced mobility and controlled transparency in multilayered reduced graphene oxide quantum dots: a charge transport study.

Reduced graphene oxide (rGO) layers are known to be significantly conductive along the basal plane throughout delocalized sp2 domains. Defects present in rGO implies in disordered systems with numerous localized sites, resulting in a charge transport governed mainly by a 2D variable range hopping (VRH) mechanism. These characteristics are observed even in multilayered rGO since the through-plane conduction is expected to be insubstantial. Here, we report on the multilayer assembly of functionalized rGO quantum dots (GQDs) presenting 3D VRH transport that endows elevated charge carrier mobility, ca âˆ¼ 236 cm2 V-1 s-1. Polyelectrolyte-wrapped GQDs were assembled by layer-by-layer technique (LbL), ensuring molecular level thickness control for the formed nanostructures, along with the adjustment of the film transparency (up to 92% in the visible region). The small size and the random distribution of GQDs in the LbL structure are believed to overcome the translational disorder in multilayered films, contributing to a 3D interlayer conduction that enhances the electronic properties. Such high-mobility, transparency-tunable films assembled by a cost-effective method possess interesting features and wide applicability in optoelectronics.