Integrated microring resonator sensor arrays for labs-on-chips

Planar waveguide optical ring resonators have shown great potential as compact and sensitive biochemical sensors. Advances in integrated optics based on Si technologies have allowed researchers to integrate multiple micron-sized ring resonator sensors with other optical and fluidic functions on Si chips using mass production techniques. Recent demonstrations of clinically relevant analyte detection by MRR sensor arrays have moved this technology closer to commercialization. Here, a survey of the development of microring sensor arrays for lab-on-a-chip applications is presented and illustrated with state-of-the-art examples.     

Large eddy simulation of a confined square cavity with natural convection based on compressible flow equations

Large eddy simulation of natural convection in a confined square cavity is described. The use of a complex compressible code with an artificial acoustic stiffness correction method, allows the use of higher time steps for a faster time and statistical convergence. We consider a broadly studied experimental case, consisting of a natural convective flow in a confined square cavity, with vertical walls heated at different rates (active walls), set at Ra = 1.58 × 10⁹. Turbulent boundary layers developing on the active walls and a vertical stable stratification characterize the mean flow. It is shown here that the results of this study match the experimental results reported in literature; for instance, mean velocity results. Although results for rms velocity fluctuations are barely over-predicted, the peak region is properly represented, while the greatest disagreements are found in the turbulent heat flow rate (velocity–temperature correlations). Turbulent structures were identified using different visualization methods and statistical studies. The authors found that the boundary layers on the active walls almost reach the fully turbulent regime, tending toward the laminar regime along the horizontal walls.     

Synthesis of a novel heptacoordinated Fe(III) dinuclear complex: experimental and theoretical study of the magnetic properties

A new functionalized bis-pyrazol-pyridine ligand has been prepared by reaction with hydrazine of the corresponding bis-β-diketone precursor, also unprecedented. The aerobic reaction of this ligand with ferrous thiocyanate in the presence of ascorbic or oxalic acid affords the dinuclear complex of seven-coordinate Fe(III), [Fe?(H?L2)?(ox)(NCS)?] (1), as revealed by single crystal X-ray diffraction. This may represent an entry into a new family of [Fe?] compounds with heptacoordinate metal centres. The capacity of this unusual chromophore to undergo magnetic super-exchange was investigated by means of bulk magnetization and DFT calculations. Both approaches confirmed the presence of antiferromagnetic interactions within the molecule. The theoretical investigation has served to describe the magnetic orbitals of Fe(III) in this unusual coordination geometry, as well as the exchange mechanism. A brief review of the scarce number of iron heptacoordinate complexes reported in the literature is also included and discussed.     

Dialkylaluminum N,O-dimethylhydroxylamine complex as a reagent to mask reactive carbonyl groups in situ from nucleophiles

Aluminum complexes of N,O-dimethylhydroxylamine are effective reagents to mask carbonyl groups in situ from nucleophilic addition by organolithiums, Grignard reagents, and borohydrides. The utility of this process by selectively adding nucleophiles into carbonyl groups on a variety of structures as well as distinguishing between carbonyl groups on a sensitive natural product is demonstrated. (1)H NMR analysis supports the in situ masking of the more reactive carbonyl group.     

Sun Protection Habits and Sun Exposure of Physical Education Teachers in the South of Spain

The high prevalence and increasing incidence of skin cancer (SC) is a significant public health problem. We can address its main risk factor, which is incident and accumulated solar radiation, and its damages by disseminating knowledge and promoting changes in habits and attitudes toward the sun. The influence of teachers in the education of young people is crucial. Physical education teachers (PET) spend the majority of their time outdoors, thereby exposing themselves to solar radiation daily and greatly increasing the risk of SC. We carried out a case–control study matching for age and gender through surveys about photoexposure and photoprotection habits on a sample of 200 teachers (100 PET and 100 non‐PET) on South of Spain. The results confirmed that there is a significant difference in sun exposure during the workday; PET group showed higher exposure (P < 0.01). We ascertained that photoprotection habits are deficient across the population. These data contribute to the understanding of the danger associated with poor sun protection among teachers (primary and secondary school teachers) and its mitigation. It is also worth noting that future prevention campaigns will be necessary for the subsequent correct transmission of the habits to students.     

Real‐Time Chemical Analysis of E‐Cigarette Aerosols By Means Of Secondary Electrospray Ionization Mass Spectrometry

Chemical analysis of aerosols collected from electronic cigarettes (ECs) has shown that these devices produce vapors that contain harmful and potentially harmful compounds. Conventional analytical methods used for the analysis of electronic cigarettes do not reflect the actual composition of the aerosols generated because they usually neglect the changes in the chemical composition that occur during the aerosol generation process and after collection. The aim of this work was to develop and apply a method for the real‐time analysis of electronic cigarette aerosols, based on the secondary electrospray ionization technique coupled to high‐resolution mass spectrometry, by mimicking the “vaping” process. Electronic cigarette aerosols were successfully analyzed and quantitative differences were found between the liquids and aerosols. Thanks to the high sensitivity shown by this method, more than 250 chemical substances were detected in the aerosols, some of them showing a high correlation with the operating power of the electronic cigarettes. The method also allows proper quantification of several chemical components such as alkaloids and flavor compounds.