The functionalization of silver nanoparticles (Ag NPs) by viologen dications (VGDs) is reported in this work as well as their applications in the surface-enhanced Raman scattering (SERS) detection of ...polycyclic aromatic hydrocarbons (PAHs). VGDs are able to form intermolecular cavities at interparticle junctions (SERS hot spots) where the analyte can be allocated. This leads to a giant intensification of the Raman emission of the target molecule. This effect was applied in the detection of PAHs, one of the most widespread and dangerous group of pollutants existing in the atmosphere and waters. A comparison between sensing-systems based on different VGDs (lucigenin, diquat, and paraquat) was done for the detection of two PAHs (pyrene and benzocphenanthrene). The functionalization with lucigenin (LG) provided the most powerful and stable VGD-NPs sensor, which allowed the SERS detection of pyrene (PYR) down to 10−9 M in the macro setup and in the zeptomole range for spectra obtained by single NPs aggregates (micro setup). Besides, SERS spectra afforded important structural information about the interaction mechanism of VGD and PAHs, revealing the formation of a CT complex between the VGD and PYR and changes in the host conformation. The position of the ν(Ag−Cl) band and the plasmon resonance contribution assigned to Ag dimers were also used as spectral markers to monitor the host−guest interaction.
Chirality, a foundational concept throughout science, may arise at ferromagnetic domain walls
and in related objects such as skyrmions
. However, chiral textures should also exist in other types of ...ferroic materials, such as antiferromagnets, for which theory predicts that they should move faster for lower power
, and ferroelectrics, where they should be extremely small and possess unusual topologies
. Here, we report the concomitant observation of antiferromagnetic and electric chiral textures at domain walls in the room-temperature ferroelectric antiferromagnet BiFeO
. Combining reciprocal and real-space characterization techniques, we reveal the presence of periodic chiral antiferromagnetic objects along the domain walls as well as a priori energetically unfavourable chiral ferroelectric domain walls. We discuss the mechanisms underlying their formation and their relevance for electrically controlled topological oxide electronics and spintronics.
The developmental journey of cortical interneurons encounters several activity-dependent milestones. During the early postnatal period in developing mice, GABAergic neurons are transient preferential ...recipients of thalamic inputs and undergo activity-dependent migration arrest, wiring, and programmed cell-death. Despite their importance for the emergence of sensory experience and the role of activity in their integration into cortical networks, the collective dynamics of GABAergic neurons during that neonatal period remain unknown. Here, we study coordinated activity in GABAergic cells of the mouse barrel cortex using in vivo calcium imaging. We uncover a transient structure in GABAergic population dynamics that disappears in a sensory-dependent process. Its building blocks are anatomically clustered GABAergic assemblies mostly composed by prospective parvalbumin-expressing cells. These progressively widen their territories until forming a uniform perisomatic GABAergic network. Such transient patterning of GABAergic activity is a functional scaffold that links the cortex to the external world prior to active exploration.
Display omitted
•In the developing barrel cortex, GABAergic neurons form functional assemblies•Prospective parvalbumin interneurons segregate into spatially clustered assemblies•Somatostatin interneurons display broadly correlated firing•GABA assemblies are regulated by sensory inputs
Using in vivo imaging in the barrel cortex, Modol et al. show that prospective parvalbumin interneurons form patches of correlated activity that merge during postnatal development. These assemblies are regulated by whisker inputs and altered by sensory deprivation.
The interdependence between human occupations, lifestyle diseases and climate change provides an opportunity to address them simultaneously. Occupational therapists' training in lifestyle ...modification and knowledge about the impact of the physical environment on daily occupations puts them in a unique position to contribute to global efforts of combating climate change and lifestyle diseases through the promotion of sustainable occupations.
To illustrate how occupational therapists can contribute to global efforts of combating climate change and lifestyle diseases by framing climate change from a personal and public health perspective.
In this discussion paper we argue that occupational therapists can use education and lifestyle modification to support individuals in the prevention and management of lifestyle diseases and that they can help design and advocate for environments that promote sustainable occupations.
This discussion paper highlights the contributions that occupational therapists can make to how we understand and address climate change and lifestyle diseases.
We argue that by framing the climate change discourse from a health perspective, occupational therapists can contribute to global efforts of combating climate change and lifestyle diseases by supporting individuals to engage in sustainable occupations and communities to facilitate this engagement.
Trace detection of polycyclic aromatic hydrocarbons is reported in this work on dithiocarbamate calix4arene functionalized Ag nanoparticles by using surface-enhanced Raman scattering (SERS). SERS ...spectra informed about the existence of the pollutant by measuring its characteristic fingerprint vibrational features. In addition, SERS revealed important structural information from both the host and the analyte which was crucial to understand and deduce the host−guest interaction mechanism. The effectiveness of this system was checked for a group of PAHs: pyrene, benzocphenanthrene, triphenylene, and coronene. From the analyzed results, the affinity constants and the limit of detection were deduced for each pollutant.
Roots and rhizomes can play an important role in nutrient cycling, however, few studies have investigated how their decomposition pattern is affected by defoliation and time of the year. This 2-year ...study evaluated root-rhizome composition and decomposition of a warm-season rhizomatous perennial legume rhizoma peanut (RP; Arachis glabrata Benth.) under continuous stocking or when defoliated by clipping every 56 days. A 168-days incubation trial was performed to determine disappearance of biomass and N and changes in acid detergent fiber (ADF), acid detergent insoluble N (ADIN), and C:N ratio. Additionally, three 56-days incubations were performed each year to evaluate the disappearance coefficient (B
) and relative decay rate (k). There were no treatment differences in any response for the 168-days incubation. After 168 days, 21 and 60% of initial biomass and initial N remained, respectively. Relative decay rate for OM and N were 0.0088 and 0.0035 g g
day
, respectively. Carbon-to-N ratio decreased from 29 at day 0 to 17 at day 168. Concentration of ADIN increased from 6.9 to 19.3 g kg
, plateauing at day 79. The B
and k for remaining OM and N were greater in late than early season and could be explained by greater N concentration and lesser C:N ratio. Rapid decomposition, difference in C:N ratio from day 0 to 168, and the increase in ADIN concentration during incubation indicate large amounts of root-rhizome-soluble C at initiation of incubation. These data indicate that RP root-rhizome turnover is more responsive to season than defoliation frequency.
Flurpiridaz F-18 (flurpiridaz) is a novel positron emission tomography (PET) myocardial perfusion imaging tracer.
The purpose of this study was to further assess the diagnostic efficacy and safety of ...flurpiridaz for the detection and evaluation of coronary artery disease (CAD) defined as ≥50% stenosis by quantitative invasive coronary angiography (ICA).
In this second phase 3 prospective multicenter clinical study, 730 patients with suspected CAD from 48 clinical sites in the United States, Canada, and Europe were enrolled. Patients underwent 1-day rest/stress flurpiridaz PET and 1- or 2-day rest-stress Tc-99m–labeled single photon emission computed tomography (SPECT) before ICA. PET and SPECT images were read by 3 experts blinded to clinical and ICA data.
A total of 578 patients (age 63.7 ± 9.5 years) were evaluable; 32.5% were women, 52.3% had body mass index ≥30 kg/m2, and 33.6% had diabetes. Flurpiridaz PET met the efficacy endpoints of the study; its sensitivity and specificity were significantly higher than the prespecified threshold value by 2 of the 3 readers. The sensitivity of flurpiridaz PET was higher than SPECT (80.3% vs 68.7%; P = 0.0003) and its specificity was noninferior to SPECT (63.8% vs 61.7%; P = 0.0004). PET area under the receiver-operating characteristic curves were higher than SPECT in the overall population (0.80 vs 0.68; P < 0.001), women, and obese patients (P < 0.001 for both). Flurpiridaz PET was superior to SPECT (P < 0.001) for perfusion defect size/severity evaluation, image quality, diagnostic certainty, and radiation exposure. Flurpiridaz PET was safe and well tolerated.
This second flurpiridaz PET myocardial perfusion imaging trial shows that flurpiridaz has utility as a new tracer for CAD detection, specifically in women and obese patients. (An International Study to Evaluate Diagnostic Efficacy of Flurpiridaz 18F Injection PET MPI in the Detection of Coronary Artery Disease CAD; NCT03354273)
Display omitted
PDF
