Subcentimeter depth resolution using a single-photon counting time-of-flight laser ranging system at 1550 nm wavelength

We demonstrate subcentimeter depth profiling at a stand off distance of 330m using a time-of-flight approach based on time-correlated single-photon counting. For the first time to our knowledge, the photon-counting time-of-flight technique was demonstrated at a wavelength of 1550nm using a superconducting nanowire single-photon detector. The performance achieved suggests that a system using superconducting detectors has the potential for low-light-level and eye-safe operation. The system’s instrumental response was 70ps full width at half-maximum, which meant that 1cm surface-to-surface resolution could be achieved by locating the centroids of each return signal. A depth resolution of 4mm was achieved by employing an optimized signal-processing algorithm based on a reversible jump Markov chain Monte Carlo method

Inhibition of DDAH1, but not DDAH2, results in apoptosis of a human trophoblast cell line in response to TRAIL.

STUDY QUESTION: Does inhibition of dimethylarginine dimethylaminohydrolase (DDAH) increase the sensitivity of trophoblasts to TRAIL-induced apoptosis? SUMMARY ANSWER: Inhibition of DDAH1, but not DDAH2, increases the sensitivity of trophoblasts to TRAIL-induced apoptosis. WHAT IS KNOWN ALREADY: Successful human pregnancy is dependent on adequate trophoblast invasion and remodelling of the maternal spiral arteries. Increased trophoblast apoptosis is seen in pregnancies complicated by pre-eclampsia. The mechanism underlying this increase is unknown. We have previously shown that nitric oxide (NO) is involved in regulating trophoblast motility and invasion, and have also demonstrated an important role for NO in regulating trophoblast sensitivity to apoptotic stimuli. DDAH is an enzyme that metabolizes asymmetric dimethylarginine (ADMA), an endogenous inhibitor of NO synthesis, previously shown to be elevated in the plasma of pre-eclamptic mothers. STUDY DESIGN, SIZE, DURATION: This study used the human extravillous trophoblast-derived cell line SGHPL-4 cells. All experiments were performed at least three times. PARTICIPANTS/MATERIALS, SETTING, METHODS: The effect of DDAH on trophoblast apoptosis was examined using siRNA and time-lapse microscopy. Changes in the expression of DDAH were followed by PCR and western blot analysis. Receptor expression was followed by flow cytometry. MAIN RESULTS AND THE ROLE OF CHANCE: Inhibiting the expression of DDAH1, but not DDAH2, resulted in a significant increase in the sensitivity of the EVT cell line SGHPL-4 to tumour necrosis factor related apoptosis inducing ligand (TRAIL) induced apoptosis (P < 0.01). This response could be mimicked by the addition of Asymmetric Dimethylarginine (ADMA), an endogenous inhibitor of NO synthesis and the substrate for both isoforms of DDAH. We further showed that this increased sensitivity to apoptosis is accompanied by a significant increase in the expression of TRAIL receptor 2 (TR2; P < 0.05) but not TRAIL receptor 1 (TR1). LIMITATIONS, REASONS FOR CAUTION: This study was performed only in vitro using a well characterized trophoblast cell line, SGHPL-4, derived from first trimester extravillous trophoblasts. WIDER IMPLICATIONS OF THE FINDINGS: This study provides new insight into the role of the DDAH/ADMA pathway in the regulation of trophoblast function. Both dysregulation of DDAH and the accumulation of ADMA have been associated with the development of pre-eclampsia. This is the first study to implicate the DDAH/ADMA pathway as a mechanism that might underlie the poor trophoblast invasion seen in this common pregnancy disorder. STUDY FUNDING/COMPETING INTERESTS: B.A.L. was supported by a grant from Action Medical Research UK (SP4577). A.E.W. was supported by a grant from the Wellcome Trust (091550). There are no competing interests and the authors have no conflict interest to declare

Electron scattering in multi-wall carbon-nanotubes

We analyze two scattering mechanisms that might cause intrinsic electronic resistivity in multi-wall carbon nanotubes: scattering by dopant impurities, and scattering by inter-tube electron-electron interaction. We find that for typically doped multi-wall tubes backward scattering at dopants is by far the dominating effect.Comment: 6 pages, 2 figures, to appear in Phys. Rev.

Macrophage polarisation affects their regulation of trophoblast behaviour

Introduction During the first trimester of human pregnancy, fetally-derived extravillous trophoblast (EVT) cells invade into uterine decidua and remodel the uterine spiral arteries to ensure that sufficient blood reaches the maternal-fetal interface. Decidual macrophages have been implicated in the regulation of decidual remodelling and aberrant activation of these immune cells is associated with pre-eclampsia. Methods The monocytic cell line THP-1 was activated to induce an M1 or M2 phenotype and the conditioned media was used to treat the EVT cell line SGHPL-4 in order to determine the effect of macrophage polarisation on trophoblast behaviour in-vitro. SGHPL-4 cell functions were assessed using time-lapse microscopy, endothelial-like tube formation assays and western blot. Results The polarisation state of the THP-1 cells was found to differentially alter the behaviour of trophoblast cells in-vitro with pro-inflammatory M1 conditioned media significantly inhibiting trophoblast motility, impeding trophoblast tube formation, and inducing trophoblast expression of caspase 3, when compared to anti-inflammatory M2 conditioned media. Discussion Macrophages can regulate trophoblast functions that are critical during decidual remodelling in early pregnancy. Importantly, there is differential regulation of trophoblast function in response to the polarisation state of these cells. Our studies indicate that the balance between a pro- and anti-inflammatory environment is important in regulating the cellular interactions at the maternal-fetal interface and that disturbances in this balance likely contribute to pregnancy disorders associated with poor trophoblast invasion and vessel remodelling

Magnetic Moments of JP=3/2+J^P=3/2^+ Heavy Baryons Using Effective Mass and Screened Charge Scheme

Magnetic moments of heavy charmed baryons with $J^P=3/2^+$ are predicted employing the concept of effective quark mass and screened charge of quark. We also extend our scheme to predict the $3/2^+ --> 1/2^+$ transition magnetic moments. A comparison of our results with the predictions obtained in recent models is presented.Comment: 19 pages, Accepted for publication in EPJ-

Non-stoichiometric silicon nitride for future gravitational wave detectors

Silicon nitride thin films were deposited at room temperature employing a custom ion beam deposition (IBD) system. The stoichiometry of these films was tuned by controlling the nitrogen gas flow through the ion source and a process gas ring. A correlation is established between the process parameters, such as ion beam voltage and ion current, and the optical and mechanical properties of the films based on post-deposition heat treatment. The results show that with increasing heat treatment temperature, the mechanical loss of these materials as well as their optical absorption decreases producing films with an extinction coefficient as low as k = 6.2(±0.5) × 10−7 at 1064 nm for samples annealed at 900°C. This presents the lowest value for IBD SiNx within the context of gravitational wave detector applications. The mechanical loss of the films was measured to be Φ = 2.1(±0.6) × 10−4 once annealed post deposition to 900°C

Non-stoichiometric silicon nitride for future gravitational wave detectors

Silicon nitride thin films were deposited at room temperature employing a custom ion beam deposition (IBD) system. The stoichiometry of these films was tuned by controlling the nitrogen gas flow through the ion source and a process gas ring. A correlation is established between the process parameters, such as ion beam voltage and ion current, and the optical and mechanical properties of the films based on post-deposition heat treatment. The results show that with increasing heat treatment temperature, the mechanical loss of these materials as well as their optical absorption decreases producing films with an extinction coefficient as low as k=6.2(±0.5)×10−7 at 1064 nm for samples annealed at 900 ∘C. This presents the lowest value for IBD SiN x within the context of gravitational wave detector applications. The mechanical loss of the films was measured to be ϕ=2.1(±0.6)×10−4 once annealed post deposition to 900 ∘C

Genetic predisposition influences plasma lipids of participants on habitual diet, but not the response to reductions in dietary intake of saturated fatty acids

Objective: SNPs identified from genome wide association studies associate with lipid risk markers of cardiovascular disease. This study investigated whether these SNPs altered the plasma lipid response to diet in the ‘RISCK’ study cohort. Methods: Participants (n = 490) from a dietary intervention to lower saturated fat by replacement with carbohydrate or monounsaturated fat, were genotyped for 39 lipid-associated SNPs. The association of each individual SNP, and of the SNPs combined (using genetic predisposition scores), with plasma lipid concentrations was assessed at baseline, and on change in response to 24 weeks on diets. Results: The associations between SNPs and lipid concentrations were directionally consistent with previous findings. The genetic predisposition scores were associated with higher baseline concentrations of plasma total(P = 0.02) and LDL (P = 0.002) cholesterol, triglycerides (P = 0.001) and apolipoprotein B (P = 0.004), and with lower baseline concentrations of HDL cholesterol (P < 0.001) and apolipoprotein A-I (P < 0.001). None of the SNPs showed significant association with the reduction of plasma lipids in response to the dietary interventions and there was no evidence of diet-gene interactions. Conclusion: Results from this exploratory study have shown that increased genetic predisposition was associated with an unfavourable plasma lipid profile at baseline, but did not influence the improvement in lipid profiles by the low-saturated-fat diets

Search for continuous gravitational wave emission from the Milky Way center in O3 LIGO-Virgo data

We present a directed search for continuous gravitational wave (CW) signals emitted by spinning neutron stars located in the inner parsecs of the Galactic Center (GC). Compelling evidence for the presence of a numerous population of neutron stars has been reported in the literature, turning this region into a very interesting place to look for CWs. In this search, data from the full O3 LIGO-Virgo run in the detector frequency band [10,2000]  Hz have been used. No significant detection was found and 95% confidence level upper limits on the signal strain amplitude were computed, over the full search band, with the deepest limit of about 7.6×10−26 at ≃142  Hz. These results are significantly more constraining than those reported in previous searches. We use these limits to put constraints on the fiducial neutron star ellipticity and r-mode amplitude. These limits can be also translated into constraints in the black hole mass–boson mass plane for a hypothetical population of boson clouds around spinning black holes located in the GC

Critical behavior of the two-dimensional N-component Landau-Ginzburg Hamiltonian with cubic anisotropy

We study the two-dimensional N-component Landau-Ginzburg Hamiltonian with cubic anisotropy. We compute and analyze the fixed-dimension perturbative expansion of the renormalization-group functions to four loops. The relations of these models with N-color Ashkin-Teller models, discrete cubic models, planar model with fourth order anisotropy, and structural phase transition in adsorbed monolayers are discussed. Our results for N=2 (XY model with cubic anisotropy) are compatible with the existence of a line of fixed points joining the Ising and the O(2) fixed points. Along this line the exponent $\eta$ has the constant value 1/4, while the exponent $\nu$ runs in a continuous and monotonic way from 1 to $\infty$ (from Ising to O(2)). For N\geq 3 we find a cubic fixed point in the region $u, v \geq 0$, which is marginally stable or unstable according to the sign of the perturbation. For the physical relevant case of N=3 we find the exponents $\eta=0.17(8)$ and $\nu=1.3(3)$ at the cubic transition.Comment: 14 pages, 9 figure