Drought effects on invertebrate metapopulation dynamics and quasi-extinction risk in an intermittent river network.

Ecological communities can remain stable in the face of disturbance if their constituent species have different resistance and resilience strategies. In turn, local stability scales up regionally if heterogeneous landscapes maintain spatial asynchrony across discrete populations-but not if large-scale stressors synchronize environmental conditions and biological responses. Here, we hypothesized that droughts could drastically decrease the stability of invertebrate metapopulations both by filtering out poorly adapted species locally, and by synchronizing their dynamics across a river network. We tested this hypothesis via multivariate autoregressive state-space (MARSS) models on spatially replicated, long-term data describing aquatic invertebrate communities and hydrological conditions in a set of temperate, lowland streams subject to seasonal and supraseasonal drying events. This quantitative approach allowed us to assess the influence of local (flow magnitude) and network-scale (hydrological connectivity) drivers on invertebrate long-term trajectories, and to simulate near-future responses to a range of drought scenarios. We found that fluctuations in species abundances were heterogeneous across communities and driven by a combination of hydrological and stochastic drivers. Among metapopulations, increasing extent of dry reaches reduced the abundance of functional groups with low resistance or resilience capacities (i.e. low ability to persist in situ or recolonize from elsewhere, respectively). Our simulations revealed that metapopulation quasi-extinction risk for taxa vulnerable to drought increased exponentially as flowing habitats contracted within the river network, whereas the risk for taxa with resistance and resilience traits remained stable. Our results suggest that drought can be a synchronizing agent in riverscapes, potentially leading to regional quasi-extinction of species with lower resistance and resilience abilities. Better recognition of drought-driven synchronization may increase realism in species extinction forecasts as hydroclimatic extremes continue to intensify worldwide.

A fully battery-powered inexpensive spectrophotometric system for high-sensitivity point-of-care analysis on a microfluidic chip.

A cost-effective b[combining low line]a[combining low line]ttery-powered s[combining low line]pectrophotometric s[combining low line]ystem (BASS) was developed for quantitative point-of-care (POC) analysis on a microfluidic chip. By using methylene blue as a model analyte, we first compared the performance of the BASS with a commercial spectrophotometric system, and further applied the BASS for loop-mediated isothermal amplification (LAMP) detection and subsequent quantitative nucleic acid analysis which exhibited a comparable limit of detection to that of Nanodrop. Compared to the commercial spectrophotometric system, our spectrophotometric system is lower-cost, consumes less reagents, and has higher detection sensitivity. Most importantly, it does not rely on external power supplies. All these features make our spectrophotometric system highly suitable for a variety of POC analyses, such as field detection.

Significant improvement in freshwater invertebrate biodiversity in all types of English rivers over the past 30 years.

There remains a persistent concern that freshwater biodiversity is in decline and being threatened by pollution. As the UK, and particularly England, is a densely populated nation with rivers of modest dilution capacity, this location is very suitable to examine how freshwater biodiversity has responded to human pressures over the past 30 years. A long-term dataset of 223,325 freshwater macroinvertebrate records from 1989 to 2018 for England was retrieved and examined. A sub-set of approximately 200 sites per English Region (1515 sites in total with 62,514 samples), with the longest and most consistent records were matched with predicted wastewater exposure, upstream land cover and terrain characteristics (latitude, altitude, slope gradient and flow discharge). To understand changes in macroinvertebrate diversity and sensitivity with respect to these parameters, the biotic indices of (i) overall family richness, (ii) Ephemeroptera, Plecoptera, Trichoptera (EPT) family richness, and (iii) the Biological Monitoring Working Party (BMWP) scores of NTAXA (number of scoring taxa) and (iv) ASPT (average score per taxon) were selected. A review of how close the BMWP scores come to those expected at minimally impacted reference sites was included. For all latitudes, altitudes, channel slope, river size, wastewater exposure levels, and differing proportions of upstream woodland, seminatural, arable and urban land cover, all diversity or sensitivity indices examined improved over this period, although this improvement has slowed in some cases post 2003. Mean overall family richness has increased from 15 to 25 family groups, a 66 % improvement. The improvement in mean EPT family richness (3 to 10 families, >300 % improvement), which are considered to be particularly sensitive to pollution, implies macroinvertebrate diversity has benefited from a national improvement in critical components of water quality.

Randomized, double-blinded phase II evaluation of docetaxel with or without doxercalciferol in patients with metastatic, androgen-independent prostate cancer.

PURPOSE: Docetaxel is standard of care for androgen-independent prostate cancer (AIPC). Doxercalciferol (1 alpha-hydroxyvitamin D2) had modest activity in phase I/II trials. Preclinical data support combining vitamin D analogues with docetaxel to treat AIPC. EXPERIMENTAL DESIGN: Chemotherapy-naive men with metastatic AIPC were randomized 1:1 to receive, on a 4-week cycle, docetaxel (35 mg/m2 i.v., days 1, 8, and 15) with or without doxercalciferol (10 microg orally, days 1-28). The primary end point was prostate-specific antigen (PSA) response. Secondary end points were progression-free survival, overall survival, objective response, and toxicity. Survival was analyzed as intent to treat. RESULTS: Seventy patients were randomized. Median follow-up was 17.6 months (range, 3.3-45.2). PSA response rate was 46.7% [95% confidence interval (95% CI), 30-64] in the doxercalciferol arm and 39.4% (95% CI, 25-56) with placebo (P = 0.560). Median progression-free survival in the doxercalciferol arm was 6.17 months (95% CI, 4.20-10.7) versus 6.20 months (95% CI, 4.83-9.07) with placebo (P = 0.764). Median overall survival in the doxercalciferol arm was 17.8 months (95% CI, 14.9-23.6) versus 16.4 months (95% CI, 11.9-23.8) with placebo (P = 0.383). Twenty-four patients in the doxercalciferol arm and 23 in the placebo arm were evaluable for objective response. No complete responses were observed. Partial objective response rate was 12.5% with doxercalciferol versus 8.7% with placebo (P = 0.672). Rate of grade > or =3 toxicity was 46% with doxercalciferol versus 42% with placebo (P = 0.785). CONCLUSIONS: Daily doxercalciferol with weekly docetaxel did not enhance PSA response rate or survival. Toxicity was similar between arms. Despite the disappointing results of this study, other vitamin D analogues remain under active investigation.

Simultaneous Detection of Dopamine and Serotonin-A Comparative Experimental and Theoretical Study of Neurotransmitter Interactions.

With the goal of accurately detecting and quantifying the amounts of dopamine (DA) and serotonin (5-HT) in mixtures of these neurotransmitters without using any labelling, we present a detailed, comparative computational and Raman experimental study. Although discrimination between these two analytes is achievable in such mixtures for concentrations in the millimolar range, their accurate quantification remains unattainable. As shown for the first time in this work, the formation of a new composite resulting from their interactions with each other is the main reason for this lack of quantification. While this new hydrogen-bonded complex further complicates potential analyte discrimination and quantification at concentrations characteristic of physiological levels (i.e., nanomolar concentrations), it can also open new avenues for its use in drug delivery and pharmaceutical research. This remark is based not only on chemical interactions analyzed here from both theoretical and experimental approaches, but also on biological relationship, with consideration of both functional and neural proximity perspectives. Thus, this research constitutes an important contribution toward better understanding of neural processes, as well as toward possible future development of label-free biosensors.

Phase II trial of weekly paclitaxel in patients with advanced melanoma.

New therapies are needed to improve the prognosis of patients with metastatic melanoma. This study evaluates the safety and efficacy of weekly paclitaxel in patients with metastatic melanoma. Patients received paclitaxel at 80 mg/m over 1 h, weekly for 3 weeks, followed by a 1-week rest period. Disease status was assessed every other cycle. Treatment was continued until patients experienced either disease progression or unacceptable toxicity. Twenty-seven patients were enrolled in this phase II clinical trial. Of these patients, two were subsequently determined to be ineligible. All patients, however, were considered to be evaluable for toxicity and all patients were included for response assessment in an intention-to-treat analysis. Patients received paclitaxel for a median of two cycles (range, <1-8). None of the 27 patients showed a response to treatment. Eight patients had stable disease. The median progression-free survival was 1.8 months (95% confidence interval, 1.7-2.5 months) and the median survival was 7.6 months (95% confidence interval, 4.7-9.7 months). The most common grade 3 toxicity was neutropenia (four patients) and one patient had grade 4 neutropenia. Other treatment-related grade 3 toxicities included hypersensitivity reaction (one patient) and diarrhoea (one patient). Of note, five patients had peripheral neuropathy; however, in each case, the neuropathy was only grade 1. Weekly paclitaxel is relatively well tolerated and can maintain disease stability for some metastatic melanoma patients. Unfortunately, the anti-tumour activity of this single-agent therapy is low and additional treatment innovations are needed.

An embedded polymer piezoresistive microcantilever sensor.

We have developed a new type of chemical microsensor based on piezoresistive microcantilever technology. In this embedded polymer microsensor, a piezoresistive microcantilever is partially "embedded" into a polymeric material. Swelling of the polymer upon analyte exposure is measured as a simple resistance change in the embedded cantilever. Arrays of these sensors, each employing a different polymeric material, provide for the identification of a wide range of chemical vapor analytes. Advantages of this system over previous "surface" piezoresistive microcantilever chemical sensors include enhanced mechanical simplicity (no mechanical approach necessary), greater resistance to shock or movement, and lower cost.