2. Two fully-factorial mesocosm experiments (one for each crayfish pair) were used to investigate crayfish diet, and their impact on benthic invertebrate community structure, benthic algal standing stock and leaf litter decomposition rates, in allopatric and sympatric populations, compared to a crayfish free control. We used stable isotope analysis to examine crayfish diet in the mesocosms and in allopatric populations of each species in the Thames catchment.3. Isotopic niche width did not vary significantly between allopatric and sympatric populations of crayfish pairs in the mesocosms and isotopic niche partitioning in all the wild populations suggests the invaders can coexist.4. All four species altered benthic invertebrate community structure but with differing functional effects, often mediated via trophic cascades. Red swamp crayfish predation upon snails evidently promoted benthic algal standing stock via reduction in grazing pressure. However, a trophic cascade whereby the crayfish consumed native invertebrate shredders, causing a reduction in net leaf litter decomposition, was decoupled by red swamp and signal crayfish since they consumed leaf litter directly and thus moderated the cascade to a trickle when in sympatry with Turkish or virile crayfish, respectively. 6. Our results suggest that the combined effect of multiple invasions on the ecosystem can reflect either an additive effect of their independent impacts, or an amplified effect, which is greater than the sum of their independent impacts. A lack of general pattern in their effects makes any potential management strategy more complex.

Multiplexed detection and quantification of structurally similar drug molecules, methylxanthine MeX, incl. theobromine TBR, theophylline TPH and caffeine CAF, have been demonstrated via solution-based surface-enhanced Raman spectroscopy (SERS), achieving highly...

A growing body of experimental research suggests that speech supplementation strategies can markedly increase speech intelligibility for individuals with dysarthria (D. Beukelman & K. Yorkston, 1977; E. Crow & P. Enderby, 1989; L. Hunter, T. Pring, & S. Martin, 1991; K. C. Hustad & D. R. Beukelman, 2001). However, studies in which speech supplementation strategies were actually implemented by speakers with dysarthria are limited, leaving their clinical efficacy unknown. The present study compared intelligibility and speech rate differences following speaker implementation of 3 strategies (topic, alphabet, and combined topic and alphabet supplementation) and a habitual (noncued) speech control condition for 5 speakers with severe dysarthria. Results revealed that combined cues and alphabet cues yielded significantly higher intelligibility scores and slower speech rates than topic cues and noncued speech. Overall, topic cues and noncued speech did not differ from one another with regard to intelligibility or speech rate. Combined cues and alphabet cues did not differ from one another with regard to intelligibility; however, speech rate was significantly different between the 2 strategies. Individual differences among speakers were generally consistent with group findings. Results were somewhat different from previous research in which strategies were experimentally superimposed on the habitual speech signal. However, findings provide evidence that alphabet cues and combined cues can have an important effect on intelligibility for speakers with severe dysarthria.

fingerprints in the form of Raman scattering signals are significantly enhanced when target molecules are in close proximity to the surface of plasmonic nanostructures. [1] In particular, SERS detection schemes show promise in point-of-care biosensing and on-site environmental monitoring owing to their key advantages, including high sensitivity, multiplexing capability, minimal sample preparation, water tolerance, and compatibility to portable devices. Nevertheless, their widespread utilization is still hindered by the challenge in developing a facile fabrication scheme for highly precise and reproducible SERS substrates.

This work describes a rapid and highly sensitive method for the quantitative detection of an important biomarker, uric acid (UA), via surface-enhanced Raman spectroscopy (SERS) with a low detection limit of ~0.2 M for multiple characteristic peaks in the fingerprint region, using a modular spectrometer. This biosensing scheme is mediated by the host-guest complexation between a macrocycle, cucurbit[7]uril (CB7), and UA, and the subsequent formation of precise plasmonic nanojunctions within the self-assembled Au NP: CB7 nanoaggregates. A facile Au NP synthesis of desirable sizes for SERS substrates has also been performed based on the classical citrate-reduction approach with an option to be facilitated using a lab-built automated synthesizer. This protocol can be readily extended to multiplexed detection of biomarkers in body fluids for clinical applications. INTRODUCTION:Uric acid, which is the end product of metabolism of purine nucleotides, is an important