Star - Planet - Debris Disk Alignment in the HD 82943 system: Is planetary system coplanarity actually the norm?

Recent results suggest that the two planets in the HD 82943 system are inclined to the sky plane by 20 +/- 4deg. Here, we show that the debris disk in this system is inclined by 27 +/- 4deg, thus adding strength to the derived planet inclinations and suggesting that the planets and debris disk are consistent with being aligned at a level similar to the Solar System. Further, the stellar equator is inferred to be inclined by 28 +/- 4deg, suggesting that the entire star - planet - disk system is aligned, the first time such alignment has been tested for radial velocity discovered planets on ~AU wide orbits. We show that the planet-disk alignment is primordial, and not the result of planetary secular perturbations to the disk inclination. In addition, we note three other systems with planets at >10AU discovered by direct imaging that already have good evidence of alignment, and suggest that empirical evidence of system-wide star - planet - disk alignment is therefore emerging, with the exception of systems that host hot Jupiters. While this alignment needs to be tested in a larger number of systems, and is perhaps unsurprising, it is a reminder that the system should be considered as a whole when considering the orientation of planetary orbits.Comment: Accepted to MNRA

A question of time: tissue adaptation to mechanical forces.

While much attention has been focused on the force-generating mechanisms responsible for shaping developing embryos, less is known about the ways in which cells in animal tissues respond to mechanical stimuli. Forces will arise within a tissue as the result of processes such as local cell death, growth and division, but they can also be an indirect consequence of morphogenetic movements in neighbouring tissues or be imposed from the outside, for example, by gravity. If not dealt with, the accumulation of stress and the resulting tissue deformation can pose a threat to tissue integrity and structure. Here we follow the time-course of events by which cells and tissues return to their preferred state following a mechanical perturbation. In doing so, we discuss the spectrum of biological and physical mechanisms known to underlie mechanical homeostasis in animal tissues

Coplanar Circumbinary Debris Disks

We present resolved Herschel images of circumbinary debris disks in the alpha CrB (HD139006) and beta Tri (HD13161) systems. We find that both disks are consistent with being aligned with the binary orbital planes. Though secular perturbations from the binary can align the disk, in both cases the alignment time at the distances at which the disk is resolved is greater than the stellar age, so we conclude that the coplanarity was primordial. Neither disk can be modelled as a narrow ring, requiring extended radial distributions. To satisfy both the Herschel and mid-IR images of the alpha CrB disk, we construct a model that extends from 1-300AU, whose radial profile is broadly consistent with a picture where planetesimal collisions are excited by secular perturbations from the binary. However, this model is also consistent with stirring by other mechanisms, such as the formation of Pluto-sized objects. The beta Tri disk model extends from 50-400AU. A model with depleted (rather than empty) inner regions also reproduces the observations and is consistent with binary and other stirring mechanisms. As part of the modelling process, we find that the Herschel PACS beam varies by as much as 10% at 70um and a few % at 100um. The 70um variation can therefore hinder image interpretation, particularly for poorly resolved objects. The number of systems in which circumbinary debris disk orientations have been compared with the binary plane is now four. More systems are needed, but a picture in which disks around very close binaries (alpha CrB, beta Tri, and HD 98800, with periods of a few weeks to a year) are aligned, and disks around wider binaries (99 Her, with a 50 yr period) are misaligned, may be emerging. This picture is qualitatively consistent with the expectation that the protoplanetary disks from which the debris emerged are more likely to be aligned if their binaries have shorter periods.Comment: accepted to MNRA

Discovery of the Fomalhaut C debris disc

Fomalhaut is one of the most interesting and well studied nearby stars, hosting at least one planet, a spectacular debris ring, and two distant low-mass stellar companions (TW PsA and LP 876-10, a.k.a. Fomalhaut B & C). We observed both companions with Herschel, and while no disc was detected around the secondary, TW PsA, we have discovered the second debris disc in the Fomalhaut system, around LP 876-10. This detection is only the second case of two debris discs seen in a multiple system, both of which are relatively wide ($\gtrsim$3000 AU for HD 223352/40 and 158 kAU [0.77 pc] for Fomalhaut/LP 876-10). The disc is cool (24K) and relatively bright, with a fractional luminosity $L_{\rm disc}/L_\star = 1.2 \times 10^{-4}$, and represents the rare observation of a debris disc around an M dwarf. Further work should attempt to find if the presence of two discs in the Fomalhaut system is coincidental, perhaps simply due to the relatively young system age of 440 Myr, or if the stellar components have dynamically interacted and the system is even more complex than it currently appears.Comment: Published in MNRAS Letters. Merry Xma

Elucidating the role of hyperfine interactions on organic magnetoresistance using deuterated aluminium tris(8-hydroxyquinoline)

Measurements of the effect of a magnetic field on the light output and current through an organic light emitting diode made with deuterated aluminium tris(8-hydroxyquinoline) have shown that hyperfine coupling with protons is not the cause of the intrinsic organic magnetoresistance. We suggest that interactions with unpaired electrons in the device may be responsible.Comment: Submitte

A target repurposing approach identifies N-myristoyltransferase as a new candidate drug target in filarial nematodes

Myristoylation is a lipid modification involving the addition of a 14-carbon unsaturated fatty acid, myristic acid, to the N-terminal glycine of a subset of proteins, a modification that promotes their binding to cell membranes for varied biological functions. The process is catalyzed by myristoyl-CoA:protein N-myristoyltransferase (NMT), an enzyme which has been validated as a drug target in human cancers, and for infectious diseases caused by fungi, viruses and protozoan parasites. We purified Caenorhabditis elegans and Brugia malayi NMTs as active recombinant proteins and carried out kinetic analyses with their essential fatty acid donor, myristoyl-CoA and peptide substrates. Biochemical and structural analyses both revealed that the nematode enzymes are canonical NMTs, sharing a high degree of conservation with protozoan NMT enzymes. Inhibitory compounds that target NMT in protozoan species inhibited the nematode NMTs with IC50 values of 2.5-10 nM, and were active against B. malayi microfilariae and adult worms at 12.5 µM and 50 µM respectively, and C. elegans (25 µM) in culture. RNA interference and gene deletion in C. elegans further showed that NMT is essential for nematode viability. The effects observed are likely due to disruption of the function of several downstream target proteins. Potential substrates of NMT in B. malayi are predicted using bioinformatic analysis. Our genetic and chemical studies highlight the importance of myristoylation in the synthesis of functional proteins in nematodes and have shown for the first time that NMT is required for viability in parasitic nematodes. These results suggest that targeting NMT could be a valid approach for the development of chemotherapeutic agents against nematode diseases including filariasis

Effects of 8-Week Ketogenic Diet on Anthropometrics, Body Composition, Metabolic Parameters, and Psychological Factors in Young Obese Population

Obese have a significantly higher Body Mass Index (BMI), which can be associated with poor nutritional intake and sedentary lifestyles. The ketogenic diet is a form of a dietary intervention which is often implemented for metabolic syndrome individuals such as obese populations. PURPOSE: The purpose of this study was to measure the effects of a ketogenic diet on anthropometrics, body composition, metabolic parameters, and psychological factors in young obese population. METHODS: Seven young obese participants (n=7, height (cm); 174.8 ± 10.9, weight (kg); 105 ± 20.7, BMI (kg∙m-2); 34.6 ± 4.8) completed an 8-week intervention with a 70:20:10 ratio of fats to proteins to carbohydrates. Participants within the study were provided three meals per day, for a total of 8 weeks. Statistical analyses were performed with IBM Statistical Package for Social Science (SPSS 27.0, SPSS Inc., Chicago, USA). All data was reported as mean and standard deviation (SD). Dependent paired t-Test was used to determine ketogenic diet intervention effects. Frequencies were used to measure results from psychological factors. Statistical significance was set a priori p ≤ 0.05. RESULTS: Participants within the study noted significant reductions in anthropometric variables during 8 weeks: body mass (Pre: 105.8 ± 20.5 kg Post: 98.9 ± 18.8 kg, p= 0.000), BMI (Pre: 34.6 ± 4.8 kg·m-2, Post: 32.2 ± 4.2 kg·m-2, p= 0.001), waist circumference (Pre: 101.5 ± 13.9 cm, Post: 96.3 ± 13.3 cm, p= 0.000), and hip circumference (Pre: 112.6 ± 11.5 cm, Post: 107.3 ± 10.8 cm, p= 0.000). Significant reductions were shown in body composition variables: body fat (Pre: 25.6 ± 0.8%, Post: 21.1 ± 1.4%, p=0.000), and lean body mass (Post: 78.9 ± 14.9 kg, Post: 78.2 ± 14.5 kg, p=.0035). Significant reductions were shown in metabolic parameters: systolic blood pressure (Post: 126.6 ± 10.0 mmHg, Post: 120 ± 6.6 mmHg, p=0.029), diastolic blood pressure (Pre: 81.7 ± 4.9 mmHg, Post: 76.3 ± 1.8 mmHg, p= 0.020), and VO2max (Pre: 47.6 ± 8.9 mL·kg-1·min-1, Post: 51.8 ± 9.2 mL·kg-1·min-1, p=0.001. Question 1 within the psychological questionnaire results shown a reduction in the negative aspect in poor health score, with a significant increase shown towards good health. Question 3g results shown that here was a significant increase in frequencies of improvement towards having no limitations regarding walking a one-mile distance. Question 9g had significant increase in individuals selecting improved overall energy levels in comparison to baseline. CONCLUSION: The 8 weeks of ketogenic diet intervention may contribute or change bioenergetics pathways and results in significant adaptations on anthropometrics, body composition, metabolic parameters, and psychological factors in young obese population

Cardiovascular Responses Between Low Cadence/High Force vs. High Cadence/Low Force Cycling

International Journal of Exercise Science 9(4): 419-426, 2016. The purpose of this study was to determine the cardiovascular responses during sustained power output comparing low cadence (LC) high force (HF) vs. high cadence (HC) Low force (LF) cycle ergometry. Nine participants (N = 9) volunteered for this study. Participants signed a Human Participants consent form. A power output of 150 watts (W) for 20 minutes was estimated as the sustainable workload. Participants were instructed to pedal steadily at 50 rpm (LC) or 100 rpm (HC) with resistance adjusted to sustain 150 W. The following measures were obtained each minute during the 20-minute protocol: average heart rate (b*min.-1), blood pressure (mmHg) and Rate Pressure Product (i.e. RPP= (SBP * HR)*100-1). Randomization was used to counterbalance both protocols (HC vs. LC) and demographic controls (N=9). Means and standard deviations (SD) were determined for age (36 ± 13.64 years), resting heart rate (68.83 ± 11.95 b*min-1), resting blood pressure (126.42 ± 13.27 mmHg), body fat percentage (male: 14.7 ± 4.3 %; female 20.6 ± 1.3 %) and height (157.80 ± 10.04 cm). A Repeated Measures Analysis of Variance (RM-ANOVA) was utilized to compare exercising values between test protocols. A Pearson Product Correlation Coefficient was utilized to determine bivariate associations between variables. A Tukey Post Hoc analysis was performed to analyze differences in LC HR and RPP. Statistical significance was set a priori at p \u3c 0.05. There were statistical differences among LC ±HR (130.51 ± 3.36), HC HR (150.83±6.49), LC RPP (204.63± 11.45), and HC RPP (245.57±25.70) Between the HC and LC protocols, the use of HC protocol elicited an increase in HR and RPP

Evolution from protoplanetary to debris discs: The transition disc around HD 166191

HD 166191 has been identified by several studies as hosting a rare and extremely bright warm debris disc with an additional outer cool disc component. However, an alternative interpretation is that the star hosts a disc that is currently in transition between a full gas disc and a largely gas-free debris disc. With the help of new optical to mid-IR spectra and Herschel imaging, we argue that the latter interpretation is supported in several ways: i) we show that HD 166191 is co-moving with the ~4 Myr-old Herbig Ae star HD 163296, suggesting that the two have the same age, ii) the disc spectrum of HD 166191 is well matched by a standard radiative transfer model of a gaseous protoplanetary disc with an inner hole, and iii) the HD 166191 mid-IR silicate feature is more consistent with similarly primordial objects. We note some potential issues with the debris disc interpretation that should be considered for such extreme objects, whose lifetime at the current brightness is mush shorter than the stellar age, or in the case of the outer component requires a mass comparable to the solid component of the Solar nebula. These aspects individually and collectively argue that HD 166191 is a 4-5 Myr old star that hosts a gaseous transition disc. Though it does not argue in favour of either scenario, we find strong evidence for 3-5 um disc variability. We place HD 166191 in context with discs at different evolutionary stages, showing that it is a potentially important object for understanding the protoplanetary to debris disc transition.Comment: accepted to MNRAS, fixed typos in abstract and axis labe