Silica Aerogels Doped with Ru(II) Tris 1,l0-Phenanthro1ine)-Electron Acceptor Dyads: Improving the Dynamic Range, Sensitivity and Response Time of Sol-Gel Based Oxygen Sensors

Complexes 1 and 2 were characterized in fluid and frozen solution and as dopants of silica aerogels. The intramolecular quenching efficiency of pendant 4-benzoyl-N-methylpyridinium group (4BzPy) is solvent dependent: emission is quenched completely in acetonitrile but not in alcohols. On the other hand, N-benzyl-N'-methylviologen (BzMeV) quenches the emission in all solvents completely. The differences are traced electrochemically to a stronger solvation effect by the alcohol in the case of 1. In fiozen matrices or absorbed on the surfaces of silica aerogel, both 1 and 2 are photoluminescent. The lack of quenching has been traced to the environmental rigidity. When doped aerogels are cooled to 77K, the emission shifts to the blue and its intensity increases in analogy to what is observed with Ru(II) complexes in media undergoing fluid-to-rigid transition. The photoluminescence of 1 and 2 from the aerogel is quenched by oxygen diffusing through the pores. In the presence of oxygen, aerogels doped with 1 can modulate their emission over a wider dynamic range than aerogels doped with 2, and both are more sensitive than aerogels doped with Ru(II) tris(1,l0- phenanthroline). In contrast to frozen solutions, the luminescent moieties in the bulk of aerogels kept at 77K are still accessible, leading to more sensitive platforms for oxygen sensors than other ambient temperature configurations

Changes in Kelp and Other Seaweeds Following Elwha Dam Removal

Kelps are ecologically important seaweeds that dominated the nearshore vegetation community prior to dam removal on the Elwha River. Dam removal is expected to trigger a shift from kelps to vegetation types that are characteristic of soft-sediment communities through restoring natural sediment supply. This study is investigating how nearshore vegetation responds to restoration of the natural sediment regime, both initially when large amounts of sediment entrained in the reservoirs are released and over longer time periods. We assessed vegetation at multiple spatial scales using three approaches. First, we measured floating kelp canopy area using aerial photography. Second, we assessed the abundance of understory kelp and seagrasses with towed videography along 50 km of shoreline. Third, scuba divers recorded density of kelp species and other seaweeds along 10 km of shoreline bracketing the river mouth. Results show profound changes in vegetation and a strong gradient in magnitude of impact related to distance from the river mouth. Floating kelp canopy area decreased 74% in the Elwha Drift Cell in the first year following project initiation (year 1), with lower magnitude losses throughout the Strait of Juan de Fuca. Area of prostrate kelps decreased by 45% (400 ha) and of stipitate kelps by 30% (130 ha) in the Elwha Drift Cell in year 1. Mean kelp density near the river mouth decreased 77% in year 1 and 95% in year 2. While all 10 kelp species declined, annuals were more impacted than perennials. In contrast to the general decline, juveniles of several kelp species appeared in late August of year 2, a substantial delay compared to typical spring timing of juvenile growth. What caused the large kelp losses and apparent delay of juvenile growth? Likely candidates include light reduction from the river plume and scour, burial or settlement inhibition from deposition. These candidates will be explored using physical data from the multidisciplinary research effort

Inhibition of HIV Env binding to cellular receptors by monoclonal antibody 2G12 as probed by Fc-tagged gp120

During natural HIV infection, an array of host receptors are thought to influence virus attachment and the kinetics of infection. In this study, to probe the interactions of HIV envelope (Env) with various receptors, we assessed the inhibitory properties of various anti-Env monoclonal antibodies (mAbs) in binding assays. To assist in detecting Env in attachment assays, we generated Fc fusions of full-length wild-type gp120 and several variable loop-deleted gp120s. Through investigation of the inhibition of Env binding to cell lines expressing CD4, CCR5, DC-SIGN, syndecans or combinations thereof, we found that the broadly neutralizing mAb, 2G12, directed to a unique carbohydrate epitope of gp120, inhibited Env-CCR5 binding, partially inhibited Env-DC-SIGN binding, but had no effect on Env-syndecan association. Furthermore, 2G12 inhibited Env attachment to primary monocyte-derived dendritic cells, that expressed CD4 and CCR5 primary HIV receptors, as well as DC-SIGN, and suggested that the dual activities of 2G12 could be valuable in vivo for inhibiting initial virus dissemination and propagation

The genetic architecture of breast papillary lesions as a predictor of progression to carcinoma

Intra-ductal papillomas (IDP) are challenging breast findings because of their variable risk of progression to malignancy. The molecular events driving IDP development and genomic features of malignant progression are poorly understood. In this study, genome-wide CNA and/or targeted mutation analysis was performed on 44 cases of IDP, of which 20 cases had co-existing ductal carcinoma in situ (DCIS), papillary DCIS or invasive ductal carcinoma (IDC). CNA were rare in pure IDP, but 69% carried an activating PIK3CA mutation. Among the synchronous IDP cases, 55% (11/20) were clonally related to the synchronous DCIS and/ or IDC, only one of which had papillary histology. In contrast to pure IDP, PIK3CA mutations were absent from clonal cases. CNAs in any of chromosomes 1, 16 or 11 were significantly enriched in clonal IDP lesions compared to pure and non-clonal IDP. The observation that 55% of IDP are clonal to DCIS/IDC indicates that IDP can be a direct precursor for breast carcinoma, not limited to the papillary type. The absence of PIK3CA mutations and presence of CNAs in IDP could be used clinically to identify patients at high risk of progression to carcinoma

Nearshore subtidal community response during and after sediment disturbance associated with dam removal

Dam removal is used increasingly to restore aquatic ecosystems and remove unnecessary or high-risk infrastructure. As the number of removals increases, there is a growing understanding about the hydrologic, geomorphic, and ecological responses to these removals. Most dam removal studies, however, focus on river and watershed responses to dam removal. The removal of two dams on the Elwha River provided a unique opportunity to characterize the response of nearshore (coastal) ecosystems. We conducted SCUBA surveys between 2011 and 2022 to quantify trajectories of change in a nearshore ecosystem during and after dam removal. We focused on the degree to which the abundances of kelp, benthic invertebrates, and fish changed in response to patterns of sediment fluxes during and after dam removal. Our findings point to two pathways of response depending on the disturbance mechanism and species type. Sites with persistent sediment deposition were characterized by wholesale community changes that did not recover to a before dam removal condition. Instead, the sites were colonized by new species that were largely absent prior to dam removal. Sites that experienced high turbidity but lacked persistent seafloor deposition were primarily characterized by a reduction in the abundance of kelp and other algae during dam removal and a rapid recovery after sediment flux to the nearshore declined. Dam removal influences on invertebrates and fish at these sites were more variable, benefiting some species and disadvantaging others. In addition to dam removal, sea star wasting syndrome and a marine heatwave exerted distinct controls on subtidal communities during the same period. The loss of the predatory sea star Pycnopodia helianthoides was associated with gains in some of its prey species, and kelp community changes reflected regional trends in ocean temperature and kelp abundance. The results presented here have important implications for understanding the response of marine ecosystems to future dam removals and similar sediment perturbation events

Effect of cadence on locomotor–respiratory coupling during upper-body exercise

Introduction: Asynchronous arm-cranking performed at high cadences elicits greater cardiorespiratory responses compared to low cadences. This has been attributed to increased postural demand and locomotor–respiratory coupling (LRC), and yet, this has not been empirically tested. This study aimed to assess the effects of cadence on cardiorespiratory responses and LRC during upper-body exercise. Methods: Eight recreationally-active men performed arm-cranking exercise at moderate and severe intensities that were separated by 10 min of rest. At each intensity, participants exercised for 4 min at each of three cadences (50, 70, and 90 rev min−1) in a random order, with 4 min rest-periods applied in-between cadences. Exercise measures included LRC via whole- and half-integer ratios, cardiorespiratory function, perceptions of effort (RPE and dyspnoea), and diaphragm EMG using an oesophageal catheter. Results: The prevalence of LRC during moderate exercise was highest at 70 vs. 50 rev min−1 (27 ± 10 vs. 13 ± 9%, p = 0.000) and during severe exercise at 90 vs. 50 rev min−1 (24 ± 7 vs. 18 ± 5%, p = 0.034), with a shorter inspiratory time and higher mean inspiratory flow (p < 0.05) at higher cadences. During moderate exercise, (Formula presented.) and fC were higher at 90 rev min−1 (p < 0.05) relative to 70 and 50 rev min−1 ((Formula presented.) 1.19 ± 0.25 vs. 1.05 ± 0.21 vs. 0.97 ± 0.24 L min−1; fC 116 ± 11 vs. 101 ± 13 vs. 101 ± 12 b min−1), with concomitantly elevated dyspnoea. There were no discernible cadence-mediated effects on diaphragm EMG. Conclusion: Participants engage in LRC to a greater extent at moderate-high cadences which, in turn, increase respiratory airflow. Cadence rate should be carefully considered when designing aerobic training programmes involving the upper-limbs