Effect of Population Density on Timing of Oviposition and Brood Size Reduction in the Burying Beetle Nicrophorus pustulatus

Burying beetles (Nicrophorus spp.) bury small carcasses to feed their larvae. Carcasses are a limited, high-quality resource and contests over carcasses become more frequent with increasing population density. Successful beetles kill eggs and larvae present on carcass. In response, females should accelerate oviposition, while offspring development should increase to minimize mortality. Both value of a carcass and frequency of contests decrease as larvae develop. If overproduction of offspring is an insurance against high mortality, females should reduce brood size as carcass value declines. Testing our predictions, we reared female burying beetles, Nicrophorus pustulatus, at high and low densities and compared oviposition and brood reduction. High-density females delayed oviposition, suggesting that high population density imposes nutritional and/or physiological stress. Females responded to the physiological constraints and the potentially high mortality rates of eggs and newly hatched larvae by lengthening oviposition period and changing brood reduction rate

Life Science Undergraduate Mentors in NE STEM 4U Significantly Outperform Their Peers in Critical Thinking Skills

The development of critical thinking skills in recent college graduates is keenly requested by employers year after year. Moreover, improving these skills can help students to better question and analyze data. Consequently, we aimed to implement a training program that would add to the critical thinking skills of undergraduate students: Nebraska Science, Technology, Engineering, and Math 4U (NE STEM 4U). In this program, undergraduates provide outreach, mentoring, and science, technology, engineering, and mathematics (STEM) education to K–8 students. To determine the impacts of serving as an undergraduate mentor in this program on critical thinking, we compared undergraduate mentors (intervention group) with nonmentor STEM majors (nonintervention, matched group) using the valid and reliable California Critical Thinking Skills Test (CCTST) as a pre/post measurement. Importantly, before the intervention, both NE STEM 4U mentors and nonmentor undergraduates scored similarly overall on the CCTST. However, the posttest, carried out one academic year later, indicated significant gains in critical thinking by the NE STEM 4U mentors compared with the nonmentors. Specifically, the math-related skills of analysis, inference, and numeracy improved significantly in mentors compared with nonmentors

Morphological traits as indicators of sexual dimorphism in Prairie Rattlesnakes (\u3ci\u3eCrotalus viridis\u3c/i\u3e)

As humans encroach into areas inhabited by predators, the potential of human-predator confrontations increases and the predators become regarded as dangerous pests. Predators exert a measure of population control over pest species such as small rodents, as well as limit the quantity and scope of diseases (e.g. spread of Hantavirus by these prey species). Control of these small rodent pest species can be aided by conserving and managing their predators like rattlesnakes (Crotalus spp). Management of any population requires detailed information on population composition and the ability to determine the key information (especially age and sex) for each individual quickly and with high accuracy. To determine the sex of a snake in the field, traditionally, a probe or forceful expulsion of the hemipenes are used. In the hands of a person unskilled in field herpetology, these methods can potentially be painful to the snake, as well as place the observer in unnecessary danger. The goal of this study was to develop a less invasive field method of determining sex for any life stage in Prairie Rattlesnakes (C. viridis) using morphological characteristics that are commonly collected. Snout-vent length (SVL), and absolute and relative measures of tail length (TL, TL/SVL), rattle length (RL, RL/SVL), number of subcaudal scales (SS, SS/SVL), and number of dorsal saddle patterns (DS, DS/SVL) were examined within and across life stages of a C. viridis populationnear Ulysses, Kansas, USA, collected from 2012-2015 to facilitate a safe working environment for a prairie restoration project. SVL, , RL, and DS as well ass RL/SVL and DS/SVL did not differ between sexes within and across life stages. TL,SS,TL/SVL and SS/SVL did not differ between male and female neonates and juveniles, but were, on average, larger in adult males than females. Regression tree analysis, however, indicated that TL and SS as well as TL/SVL and SS/SVL are not very reliable for sex determination of adult snakes. Yet, if used in conjunction with other reliable methods, such as palpation of the ventral area of a snake to determine gravidity, both absolute and relative measures of tail length and number of subcaudal scales are viable alternatives to the more invasive methods currently in use

Design and Synthesis of CNS-targeted Flavones and Analogues with Neuroprotective Potential Against H2O2- and Aβ1-42-Induced Toxicity in SH-SY5Y Human Neuroblastoma Cells

With the lack of available drugs able to prevent the progression of Alzheimer’s disease (AD), the discovery of new neuroprotective treatments able to rescue neurons from cell injury is presently a matter of extreme importance and urgency. Here, we were inspired by the widely reported potential of natural flavonoids to build a library of novel flavones, chromen-4-ones and their C-glucosyl derivatives, and to explore their ability as neuroprotective agents with suitable pharmacokinetic profiles. All compounds were firstly evaluated in a parallel artificial membrane permeability assay (PAMPA) to assess their effective permeability across biological membranes, namely the blood-brain barrier (BBB). With this test, we aimed not only at assessing if our candidates would be well-distributed, but also at rationalizing the influence of the sugar moiety on the physicochemical properties. To complement our analysis, logD7.4 was determined. From all screened compounds, the p-morpholinyl flavones stood out for their ability to fully rescue SH-SY5Y human neuroblastoma cells against both H2O2- and Aβ1-42-induced cell death. Cholinesterase inhibition was also evaluated, and modest inhibitory activities were found. This work highlights the potential of C-glucosylflavones as neuroprotective agents, and presents the p-morpholinyl C-glucosylflavone 37, which did not show any cytotoxicity towards HepG2 and Caco-2 cells at 100 μM, as a new lead structure for further development against AD.Fundação para a Ciência e a Tecnologia-UID/Multi/0612/2019Unión Europea-D3i4AD), FP7-PEOPLE-2013-IAPP, GA 61234

Mediolateral Damping of an Overhead Body Weight Support System Assists Stability During Treadmill Walking

Background Body weight support systems with three or more degrees of freedom (3-DoF) are permissive and safe environments that provide unloading and allow unrestricted movement in any direction. This enables training of walking and balance control at an early stage in rehabilitation. Transparent systems generate a support force vector that is near vertical at all positions in the workspace to only minimally interfere with natural movement patterns. Patients with impaired balance, however, may benefit from additional mediolateral support that can be adjusted according to their capacity. An elegant solution for providing balance support might be by rendering viscous damping along the mediolateral axis via the software controller. Before use with patients, we evaluated if control-rendered mediolateral damping evokes the desired stability enhancement in able-bodied individuals. Methods A transparent, cable-driven robotic body weight support system (FLOAT) was used to provide transparent body weight support with and without mediolateral damping to 21 able-bodied volunteers while walking at preferred gait velocity on a treadmill. Stability metrics reflecting resistance to small and large perturbations were derived from walking kinematics and compared between conditions and to free walking. Results Compared to free walking, the application of body weight support per-se resulted in gait alterations typically associated with body weight support, namely increased step length and swing phase. Frontal plane dynamic stability, measured by kinematic variability and nonlinear dynamics of the center of mass, was increased under body weight support, indicating reduced balance requirements in both damped and undamped support conditions. Adding damping to the body weight support resulted in a greater increase of frontal plane stability. Conclusion Adding mediolateral damping to 3-DoF body weight support systems is an effective method of increasing frontal plane stability during walking in able-bodied participants. Building on these results, adjustable mediolateral damping could enable therapists to select combinations of unloading and stability specifically for each patient and to adapt this in a task specific manner. This could extend the impact of transparent 3-DoF body weight support systems, enabling training of gait and active balance from an early time point onwards in the rehabilitation process for a wide range of mobility activities of daily life

Unlocking the in vitroanti- inflammatory and antidiabetic potential of Polygonum maritimum

Context: Several Polygonum species (Polygonaceae) are used in traditional medicine in Asia, Europe and Africa to treat inflammation and diabetes. Objective: Evaluate the in vitro antioxidant, anti-inflammatory and antidiabetic potential of methanol and dichloromethane extracts of leaves and roots of the halophyte Polygonum maritimum L. Material and methods: Antioxidant activity was determined (up to 1mg/mL) as radical-scavenging activity (RSA) of 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), copper (CCA) and iron (ICA) chelating activities and iron reducing power (FRAP). NO production was measured in lipopolysaccharide (LPS)-stimulated macrophages for 24 h at concentrations up to 100 mu g/mL and antidiabetic potential was assessed by alpha-amylase and alpha-glucosidase inhibition (up to 10 g/mL) assays. The phytochemical composition of the extracts was determined by gas chromatography-mass spectrometry (GC-MS). Results: The methanol leaf extract had the highest activity against DPPH center dot (IC50 = 26 mu g/mL) and ABTS1(+)center dot (IC50 = 140 mu g FRAP (IC50 = 48 mu g/mL) and CCA (IC50 = 770 mu g/mL). Only the dichloromethane leaf extract (LDCM) showed anti-inflammatory activity (IC50 = 48 mu g/mL). The methanol root (IC50 = 19 mu g/mL) and leaf (IC50 = 29 mu g/mL) extracts strongly inhibited baker's yeast alpha-glucosidase, but LDCM had higher rat's alpha-glucosidase inhibition (IC50 = 2527 mu g/mL) than acarbose (IC50 = 4638 mu g/mL). GC-MS analysis identified beta-sitosterol, stigmasterol, 1-octacosanol and linolenic acid as possible molecules responsible for the observed bioactivities. Conclusions: Our findings suggest P. maritimum as a source of high-value health promoting commodities for alleviating symptoms associated with oxidative and inflammatory diseases, including diabetes.XtremeBio project - Foundation for Science and Technology (FCT) [PTDC/MAR-EST/4346/2012]; Portuguese National Budget; FCT [CCMAR/Multi/04326/ 2013, IF/00049/2012, SFRH/BPD/86071/2012, UID/Multi/00612/2013

Light suppression of nitrate reductase activity in seedling and young plant tissues

Light is often reported to enhance plant nitrate reductase (NR) activity; we have identified a context in which light strongly suppresses NR activity. In vitro NR activity measurements of laboratory-grown seedlings showed strong suppression of nitrate-induced NR activity in cotyledon, hypocotyl, and root tissues of Ipomoea hederacea (L.) Jacquin; robust NR activity accumulated in nitrate-induced tissues in the dark, but was absent or significantly reduced in tissues exposed to light during the incubation. The suppressive mechanism appears to act at a point after nitrate perception; tissues pre-incubated with nitrate in the light were potentiated and developed NR activity more rapidly than nitrate-induced tissues not so pre-exposed. Suppression was affected by moderate to low light levels under full-spectrum light sources and by single-wavelength red, green, and blue sources. The suppression phenomenon persisted in early (first through fourth) leaves of glasshouse plants grown in soil, and in artificially rejuvenated cotyledons. Collectively these observations suggest a link between light perception and NR regulation that remains to be fully characterized

Coupling rheology and segregation in granular flows

During the last fifteen years there has been a paradigm shift in the continuum modelling of granular materials; most notably with the development of rheological models, such as the μ(I) μ(I) -rheology (where μ μ is the friction and I is the inertial number), but also with significant advances in theories for particle segregation. This paper details theoretical and numerical frameworks (based on OpenFOAM) which unify these currently disconnected endeavours. Coupling the segregation with the flow, and vice versa, is not only vital for a complete theory of granular materials, but is also beneficial for developing numerical methods to handle evolving free surfaces. This general approach is based on the partially regularized incompressible μ(I) μ(I) -rheology, which is coupled to the gravity-driven segregation theory of Gray & Ancey (J. Fluid Mech., vol. 678, 2011, pp. 353–588). These advection–diffusion–segregation equations describe the evolving concentrations of the constituents, which then couple back to the variable viscosity in the incompressible Navier–Stokes equations. A novel feature of this approach is that any number of differently sized phases may be included, which may have disparate frictional properties. Further inclusion of an excess air phase, which segregates away from the granular material, then allows the complex evolution of the free surface to be captured simultaneously. Three primary coupling mechanisms are identified: (i) advection of the particle concentrations by the bulk velocity, (ii) feedback of the particle-size and/or frictional properties on the bulk flow field and (iii) influence of the shear rate, pressure, gravity, particle size and particle-size ratio on the locally evolving segregation and diffusion rates. The numerical method is extensively tested in one-way coupled computations, before the fully coupled model is compared with the discrete element method simulations of Tripathi & Khakhar (Phys. Fluids, vol. 23, 2011, 113302) and used to compute the petal-like segregation pattern that spontaneously develops in a square rotating drum

Synthesis of sugars embodying conjugated carbonyl systems and related triazole derivatives from carboxymethyl glycoside lactones. Evaluation of their antimicrobial activity and toxicity.

International audienceThe synthesis of a series of pyranoid derivatives comprising a conjugated carbonyl function and related triazole derivatives, structurally suitable for bioactivity evaluation, was achieved in few steps starting from readily available carboxymethyl glycoside lactones (CMGL). 3-Enopyranosid-2-uloses were generated by oxidation/elimination of tri-O-acylated 2-hydroxy pyranosides. Subsequent Wittig olefination provided stereoselectively 2-C-branched-chain conjugated dienepyranosides with (E)-configuration around the exocyclic double bond. A heterogeneous CuI/Amberlyst-catalyzed 'click' chemistry protocol was used to convert glycosides bearing a propargyl moiety into the corresponding 1,2,3-triazoles. These new molecules were screened for their in vitro antibacterial and antifungal activities and those containing conjugated carbonyl systems demonstrated the best efficacy. (N-Dodecylcarbamoyl)methyl enone glycerosides were the most active ones among the enones tested. The α-anomer displayed very strong activities against Bacillus cereus and Bacillus subtilis and strong activity toward Enterococcus faecalis and the fungal pathogen Penicillium aurantiogriseum. The corresponding β-anomer presented a very strong inhibitory effect against two fungal species (Aspergillus niger and P. aurantiogriseum). (N-Dodecyl-/N-propargyl/or N-benzylcarbamoyl)methyl dienepyranosides exhibited selectively a strong activity toward E. faecalis. Further acute toxicity evaluation indicated low toxic effect of the (N-dodecylcarbamoyl)methyl enone glyceroside α-anomer and of the carbamoylmethyl dienepyranosides N-protected with propargyl or benzyl groups