Piperazinium Chlorocuprates(I)

The formation from aqueous solution of networks containing piperazinium hydrochlorides with copper(I) chloride is described. Four new X-ray crystal structures are reported: (H2Pip)[Cu2Cl4] (two isomeric phases: 1A and 1B), (H2MePip)[Cu3Cl5] (2), and (H2Me2Pip)[Cu4Cl6] (3) (Pip = piperazine, MePip = N-methylpiperazine, Me2Pip = N,N′-dimethylpiperazine. In 1A (P-1, a = 6.3141(2), b = 6.8248(2), c = 6.9067(2), α = 90.707(2), β = 110.748(2), γ = 110.799(2), V = 256.918(13), Z = 2) corner-sharing Cu2Cl2 rhomboid dimers form infinite chains running parallel to the a-axis. In 1B (Pbcn, a = 9.9442(6), b = 8.0622(5), c = 13.1301(7), V = 1052.67(11), Z = 8) the Cu2Cl2 dimers are linked by μ-Cl into Cu6Cl8 rings which form hexagonally tiled sheets running parallel to the a,b-plane. In 2 (P-1, a = 8.0815(7), b = 9.6584(9), c = 9.7900(8), α = 70.231(4), β = 77.180(4), γ = 70.587(4), V = 673.05(10), Z = 2) alternating Cu3Cl3 and Cu4Cl4 rings are fused to form ribbons that run parallel to the a-axis. Copper-copper interactions are present. In 3 (C2/c, a = 17.4026(6), b = 10.5295(4), c = 11.7501(8), β = 131.5490(10), V = 1611.35(14), Z = 8) relatively long Cu···Cl interactions connect Cu4Cl6 “adamantane” units into chains running parallel to the c-axis. In all cases the piperazinium ions are independent from the chlorocuprate structures, but they do show N–H···Cl interactions

2,2,3,30-Tetraphenyl-7,70-biquinoxaline

In the crystal structure of the title compound, C40H26N4, mol­ecules reside on crystallographic centers of inversion and are linked via C-HN inter­actions about inversion centers into one-dimensional chains: longer C-H(arene) inter­actions complete the inter­molecular inter­actions

Threaded Structure and Blue Luminescence of (CuCN)20(Piperazine)7

The structurally unique and highly luminescent 20 : 7 complex of CuCN with piperazine (Pip) was formed under aqueous conditions; its structure reveals two interpenetrated 2D sub-networks in 6 : 1 ratio: (CuCN)2(Pip) and (CuCN)8(Pip), the latter consisting of Cu18(CN)16(Pip)2 macrocycles

Reversible Luminescent Reaction of Amines with Copper(i) Cyanide

Copper(I) cyanide exposed to various liquid or vapor-phase amines (L) at ambient temperature produces a variety of visible photoluminescence colors via reversible formation of amine adducts. The adducts show phase matches to authentic (CuCN)Ln, n = 0.75–2.0, produced by heating CuCN with liquid amine

Conformational Change in the Chromatin Remodelling Protein MENT

Chromatin condensation to heterochromatin is a mechanism essential for widespread suppression of gene transcription, and the means by which a chromatin-associated protein, MENT, induces a terminally differentiated state in cells. MENT, a protease inhibitor of the serpin superfamily, is able to undergo conformational change in order to effect enzyme inhibition. Here, we sought to investigate whether conformational change in MENT is ‘fine-tuned’ in the presence of a bound ligand in an analogous manner to other serpins, such as antithrombin where such movements are reflected by a change in intrinsic tryptophan fluorescence. Using this technique, MENT was found to undergo structural shifts in the presence of DNA packaged into nucleosomes, but not naked DNA. The contribution of the four Trp residues of MENT to the fluorescence change was mapped using deconvolution analysis of variants containing single Trp to Phe mutations. The analysis indicated that the overall emission spectra is dominated by a helix-H tryptophan, but this residue did not dominate the conformational change in the presence of chromatin, suggesting that other Trp residues contained in the A-sheet and RCL regions contribute to the conformational change. Mutagenesis revealed that the conformational change requires the presence of the DNA-binding ‘M-loop’ and D-helix of MENT, but is independent of the protease specificity determining ‘reactive centre loop’. The D-helix mutant of MENT, which is unable to condense chromatin, does not undergo a conformational change, despite being able to bind chromatin, indicating that the conformational change may contribute to chromatin condensation by the serpin

One, two and three-dimensional ultrasound measurements of carotid atherosclerosis before and after cardiac rehabilitation: preliminary results of a randomized controlled trial.

BACKGROUND: It is still not known how patients who are post-transient ischemic attack (TIA) or post-stroke might benefit from prospectively planned comprehensive cardiac rehabilitation (CCR). In this pilot evaluation of a larger ongoing randomized-controlled-trial, we evaluated ultrasound (US) measurements of carotid atherosclerosis in subjects following TIA or mild non-disabling stroke and their relationship with risk factors before and after 6-months of CCR. METHODS: Carotid ultrasound (US) measurements of one-dimensional intima-media-thickness (IMT), two-dimensional total-plaque-area (TPA), three-dimensional total-plaque-volume (TPV) and vessel-wall-volume (VWV) were acquired before and after 6-months CCR for 39 subjects who had previously experienced a TIA and provided written informed consent to participate in this randomized controlled trial. We maintained blinding for this ongoing study by representing treatment and control groups as A or B, although we did not identify which of A or B was treatment or control. Carotid IMT, TPA, TPV and VWV were measured before and after CCR as were changes in body mass index (BMI), total cholesterol (TC), high-density lipoprotein (HDL), low-density lipoprotein (LDL), triglycerides (TG), systolic blood pressure (SBP) and diastolic blood pressure (DBP). RESULTS: There were no significant differences in US measurements or risk factors between groups A and B. There was no significant change in carotid ultrasound measurements for group A (IMT, p = .728; TPA, p = .629; TPV, p = .674; VWV, p = .507) or B (IMT, p = .054; TPA, p = .567; TPV, p = .773; VWV, p = .431) at the end of CCR. There were significant but weak-to-moderate correlations between IMT and VWV (r = 0.25, p = .01), IMT and TPV (r = 0.21, p = .01), TPV and TPA (r = 0.60, p \u3c .0001) and VWV and TPV (r = 0.22, p = .02). Subjects with improved TC/HDL ratios showed improved carotid VWV although, this was not statistically significant. CONCLUSION: In this preliminary evaluation, there were no significant differences in carotid US measurements in the control or CCR group; a larger sample size and/or longer duration is required to detect significant changes in US or other risk factor measurements

Seismic Coupling of Short-Period Wind Noise Through Mars’ Regolith for NASA’s InSight Lander

NASA’s InSight lander will deploy a tripod-mounted seismometer package onto the surface of Mars in late 2018. Mars is expected to have lower seismic activity than the Earth, so minimisation of environmental seismic noise will be critical for maximising observations of seismicity and scientific return from the mission. Therefore, the seismometers will be protected by a Wind and Thermal Shield (WTS), also mounted on a tripod. Nevertheless, wind impinging on the WTS will cause vibration noise, which will be transmitted to the seismometers through the regolith (soil). Here we use a 1:1-scale model of the seismometer and WTS, combined with field testing at two analogue sites in Iceland, to determine the transfer coefficient between the two tripods and quantify the proportion of WTS vibration noise transmitted through the regolith to the seismometers. The analogue sites had median grain sizes in the range 0.3–1.0 mm, surface densities of 1.3–1.8gcm−3, and an effective regolith Young’s modulus of 2.5−1.4+1.9MPa. At a seismic frequency of 5 Hz the measured transfer coefficients had values of 0.02–0.04 for the vertical component and 0.01–0.02 for the horizontal component. These values are 3–6 times lower than predicted by elastic theory and imply that at short periods the regolith displays significant anelastic behaviour. This will result in reduced short-period wind noise and increased signal-to-noise. We predict the noise induced by turbulent aerodynamic lift on the WTS at 5 Hz to be ∼2×10−10ms−2Hz−1/2 with a factor of 10 uncertainty. This is at least an order of magnitude lower than the InSight short-period seismometer noise floor of 10−8ms−2Hz−1/2

Assembly of the type II secretion system such as found in Vibrio cholerae depends on the novel Pilotin AspS

The Type II Secretion System (T2SS) is a molecular machine that drives the secretion of fully-folded protein substrates across the bacterial outer membrane. A key element in the machinery is the secretin: an integral, multimeric outer membrane protein that forms the secretion pore. We show that three distinct forms of T2SSs can be distinguished based on the sequence characteristics of their secretin pores. Detailed comparative analysis of two of these, the Klebsiella-type and Vibrio-type, showed them to be further distinguished by the pilotin that mediates their transport and assembly into the outer membrane. We have determined the crystal structure of the novel pilotin AspS from Vibrio cholerae, demonstrating convergent evolution wherein AspS is functionally equivalent and yet structurally unrelated to the pilotins found in Klebsiella and other bacteria. AspS binds to a specific targeting sequence in the Vibrio-type secretins, enhances the kinetics of secretin assembly, and homologs of AspS are found in all species of Vibrio as well those few strains of Escherichia and Shigella that have acquired a Vibrio-type T2SS

The Emergence of Network Inefficiencies in Infants With Autism Spectrum Disorder

Autism Spectrum Disorder (ASD) is a developmental disorder defined by behavioural features that emerge during the first years of life. Research indicates that abnormalities in brain connectivity are associated with these behavioural features. However, inclusion of individuals past the age of onset of the defining behaviours complicates interpretation of the observed abnormalities: they may be cascade effects of earlier neuropathology and behavioural abnormalities. Our recent study of network efficiency in a cohort of 24-month-olds at high and low familial risk for ASD reduced this confound; we reported reduced network efficiencies in toddlers classified as ASD. The current study maps the emergence of these inefficiencies in the first year of life