Influence of particle size on the SARS-CoV-2 spike protein detection using IgG-capped gold nanoparticles and dynamic light scattering.

Due to the unprecedented and ongoing nature of the coronavirus outbreak, the development of rapid immunoassays to detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its highly contagious variants is an important and challenging task. Here, we report the development of polyclonal antibody-functionalized spherical gold nanoparticle biosensors as well as the influence of the nanoparticle sizes on the immunoassay response to detect the SARS-CoV-2 spike protein by dynamic light scattering. By monitoring the increment in the hydrodynamic diameter (ΔDH) by dynamic light scattering measurements in the antigen-antibody interaction, SARS-CoV-2 S-protein can be detected in only 5 min. The larger the nanoparticles, the larger ΔDH in the presence of spike protein. From adsorption isotherm, the calculated binding constant (K D ) was 83 nM and the estimated limit of detection was 13 ng/mL (30 pM). The biosensor was stable up to 90 days at 4 °C. Therefore, the biosensor developed in this work could be potentially applied as a fast and sensible immunoassay to detect SARS-CoV-2 infection in patient samples.

Impairment of swimming performance in Tritia reticulata (L.) veligers under projected ocean acidification and warming scenarios.

Tritia reticulata (L.) is a neogastropod ubiquitous in the coastal communities of the NE Atlantic. Its life cycle relies on the swimming performance of planktonic early life stages, whose sensitivity to the climate conditions projected for the near future, namely of ocean acidification (OA) and warming (W), is, to our best knowledge, unknown. To examine the resilience of larval stages to future environmental conditions, this work investigates the effect of OA-W on the swimming performance of T. reticulata veligers under a range of experimental conditions, based on the end-of-century projections of the Intergovernmental Panel on Climate Change. Veligers were exposed to six experimental scenarios for 14 days, employing a full factorial design with three temperatures (T°C: 18, 20 and 22 °C) and two pH levels (pHtarget: 8.1 and 7.8). Mortality was assessed throughout the trial, after which swimming behaviour - characterised by the activity, speed and the distance travelled by veligers - was analysed by automated video recordings in a Zebrabox® device. Mortality increased with OA-W and, although more active, larvae travelled shorter distances revealing reduced swimming speed under acidic and warmer conditions, with the interaction of the tested stressors - pH and T°C - being highly significant. Results motivated the morpho-histological analysis of larvae preserved at the end of the trial, to check for the integrity of the organs involved in veligers' motion: statocysts, velum and foot. Statocyst and velar morpho-structure were conserved but histological damage of metapodial epithelia was evident under acidity, namely an apparent hypertrophy and protrusion of the secretory cells, with dispersed pigmented granules and, at 22 °C, less cilia, with potential functional implications. Negative consequences of the OA-W scenarios tested on veligers' competence are unveiled, pointing towards the eminent threat these phenomena constitute to T. reticulata perpetuation in case no mitigation measures are taken, and projections become effective.

Minimal state tomography of spatial qubits using a spatial light modulator.

We report minimal quantum state tomography with spatial qubits created by a pair of parametric down converted twin-photons passing through a double-slit. A novel experimental setup is used, which includes a Spatial Light Modulator, as a fundamental tool, to reconstruct the state density matrix. The theory needed to perform a minimal quantum tomography is described. The density matrix is experimentally obtained for the two-qubit photonic states in spatial variables.

Staphylococcus epidermidis adhesion on modified urea/urethane elastomers.

Block urea/urethane co-polymer films present elastomeric properties with the possible tuning of their surface properties within a wide range and are therefore considered relevant surfaces for possible medical applications. In particular, thin free standing films of urea/urethane elastomers with two soft segments, polypropylene oxide and more hydrophobic polybutadiene, develop multistable states with surface topography features with remarkable regularity. Moreover, complex surface structures may be obtained by UV radiation treatment followed by suitable mechanical action and also by extraction of the elastomer with a suitable solvent. In the present work, different modified elastomer samples were assayed for Staphylococcus epidermidis adhesion during 2 h and the extent of bacterial adhesion was evaluated by automatic cell enumeration. Bacterial adhesion assays demonstrate that the typical trend relating the increase in the number of adhered bacteria with the increase of the surface roughness does not hold for all materials. Results may be interpreted taking into account both the surface topography and the different types of micro-phase segregation of hydrophobic and hydrophilic parts of the elastomer.

PCR-based diagnosis of a case of herpetic whitlow in an AIDS patient.

Herpetic infections are common complications in AIDS patients. The clinical features could be uncommon and antiviral chemotherapy is imperative. A rapid diagnosis could prevent incorrect approaches and treatment. The polymerase chain reaction is a rapid, specific and sensible method for DNA amplification and diagnosis of infectious diseases, especially viral diseases. This approach has some advantages compared with conventional diagnostic procedures. Recently we have reported a new PCR protocol to rapid diagnosis of herpetic infections with suppression of the DNA extraction step. In this paper we present a case of herpetic whitlow with rapid diagnosis by HSV-1 specific polymerase chain reaction using the referred protocol.

Tratamento intensivo do estado de choque. Determinantes clinicos do prognostico. / Intensive treatment of shock state. Clinical determinants of the prognosis

Neste trabalho sao apresentados os resultados do tratamento, em Centro de Tratamento Intensivo, de 356 pacientes em estado de choque. A correlacao entre os dados clinicos e a evolucao foi feita com base numa analise computadorizada dos dados obtidos de 274 tabulacoes; aquelas consideradas mais importantes sao descritas. A mortalidade foi de 63,5% sendo mais elevada (p < 0,01) na presenca de cardiopatia (72,9%), insuficiencia respiratoria (81,4%), acidose metabolica (75,5%) e quando o choque se instalou apos a admissao no CTI (82,6%). As intervencoes terapeuticas nao destinadas ao tratamento do mecanismo primario desencadeante do choque e a presenca de complicacoes do choque (insuficiencia renal aguda, arritmias cardiacas, parada cardiaca e disturbios da consciencia) estiveram relacionadas com elevada mortalidade (p < 0,01). A mortalidade foi tambem influenciada pela etiologia primaria do estado de choque: hipovolemico (45,7%), septicemico (54,8%), cardiogenico (74,7%), misto (75,0%) e indeterminado (81,6%) - (p < 0,01)