Well-resolved large eddy simulation of shock train in a pipe flow at a moderate Reynolds number is performed using an explicit filtering based LES approach and additional adaptive filtering near the shocks. The inflow to the pipe with shock train is from a fully-developed turbulent pipe flow at centerline Mach number 1.67 and friction Reynolds number 1115. The shock train appearing in the present pipe flow consists of 4 to 5 shocks followed by a shockless mixing region. The adaptive filtering procedure used here is capable of capturing shocks appearing in the current flow. Pronounced instantaneous flow separation occurs near the foot of the first shock while smaller separation bubbles are observed near the second and third shocks. The shock train is studied in detail with a focus on the effects of the shocks on the Reynolds stresses, both on the inner and outer peaks.

Large-eddy simulations of spatially developing round jets are performed with the aim of understanding the effects of compressibility on mean and turbulence characteristics of jets at a high Reynolds number. These jets are perfectly expanded with inflow Mach numbers of 0.45, 0.9 and 1.8 and Reynolds number of 5 x 10(5) based on jet diameter and centerline velocity u(0) at inflow. The results indicate that the length of potential core increases with the Mach number in accordance with previous experimental and numerical investigations. Reduction in the jet spreading rate and velocity decay rate is noted with increasing Mach number. In the fully developed region, the computed Reynolds stresses are lower for the higher Mach number jet.

Large-eddy simulation of subsonic round jet impinging on a flat circular plate is performed at Mach number 0.9 and Reynolds number 25,000, based on the diameter and centerline velocity of the jet for two impingement distances [Formula: see text] of [Formula: see text] and [Formula: see text] using high-order compact finite difference scheme. The complex flow phenomena associated with the impinging jet flowfield are studied. The power spectral density (PSD) of instantaneous pressure reveals a discrete impingement tone. Dynamic mode decomposition (DMD) of the velocity and pressure is also done for both cases to extract the most dominant modes of the flow. The fundamental impingement tone frequency obtained from the PSD of pressure is identical to that of the first dominant pressure mode obtained from DMD. Both axisymmetric and semihelical modes are present for the [Formula: see text] case, but only axisymmetric modes are there in the [Formula: see text] case, and it is noted that the modes corresponding to the fundamental tone have an axisymmetric structure. Also, one dominant mode showing the wall jet structures denoting the liftoff of fluid from the wall after impingement at some radial distance away from the stagnation region is present in both impingement distance cases.

Nitrite (NO2 -) serves as a pool of nitric oxide (NO) in biological systems under hypoxic conditions, and it is transformed to NO by nitrite reductase (NiR) enzyme in the presence of acid (H+ ions). However, NO synthases (NOSs) generate NO via L-arginine oxidation in normoxic conditions. Previously, acid-induced NO2 - reduction chemistry was modeled on mono-metallic 3d-metals, generating metal-nitrosyls or NO(g) with H2O or H2O2 products. Herein, to understand the relative potency of a bimetallic system, we report the acid-induced reductive conversion of η2-bound NO2 - to NO on CuII-CoII centers of a hetero-bimetallic CuII-nitrito-CoII complex, [(LN8H)CuII-NO2 --CoII]3+ (CuII-NO2 --CoII, 2) bearing an octadentate N8-cryptand ligand (LN8H). The CuII-NO2 --CoII generates [CuII(LN8H)CoII]4+ (1) upon reaction with one equiv. acid (HClO4, H+ ions source) with NO(g) via a presumed transient nitrousacid (ONOH) intermediate species. Likewise, this NO2 - reduction was found to form H2O, which is believed to be from the decomposition of H2O2, an intermediate species. In addition, complex 2, in the presence of more than one equiv. H+ ions also showed the formation of NO(g) with H2O. Mechanistic investigations, using 15N-labeled-15NO2 -, 18O-labeled-18O14N16O- and 2H-labeled-DClO4 (D+ source), revealed that the N-atom and O-atom in the 14/15NO and 14N18O gases are derived from NO2 - ligand and H-atom in H2O derived from H+-source, respectively.

High-order accurate Large-eddy simulations (LES) have been carried out for compressible, turbulent flow through two bell-shaped convergent-divergent nozzles- one with a short divergent portion and the other with a longer one. An explicit filtering approach based on approximate deconvolution method is used for the LES. The nozzles have isothermal walls and circular cross-sections. The incoming flow is a turbulent, subsonic fully developed pipe flow at centreline Mach number of around 0.4 and friction Reynolds number 216. An adaptive filter is used to capture the shocks appearing in the divergent portion of the nozzles. The complicated behaviour of the mean flow, Reynolds stresses, production and pressure-strain terms of the axial Reynolds stress budget in the shock train region is shown. The broadband nature of the shock train oscillations having multiple dominant frequencies in these nozzles is observed in the present LES.

Large eddy simulations of a subsonic round jet impinging on a flat plate is performed at two Mach numbers 0.4 and 0.9 and at Reynolds number 25000, calculated using centerline velocity and jet diameter at inlet. Nozzle to plate distance for these cases is taken as eight times the jet radius. In case of Mach 0.4 jet the mean centerline velocity remains nearly constant throughout the free jet region but there are certain jumps in mean velocity profile of Mach 0.9 jet due to presence of weak shocks in the flow. Reynolds stress profiles are also presented and compared for these cases.

Nitrite reductase (NiR) catalyzes nitrite (NO2 -) to nitric oxide (NO) transformation in the presence of an acid (H+ ions/pH) and serves as a critical step in NO biosynthesis. In addition to the NiR enzyme, NO synthases (NOSs) participate in NO production. The chemistry involved in the catalytic reduction of NO2 -, in the presence of H+, generates NO with a H2O molecule utilizing two H+ + one electron from cytochromes and is believed to be affected by the pH. Here, to understand the effect of H+ ions on NO2 - reduction, we report the acid-induced NO2 - reduction chemistry of a nonheme FeII-nitrito complex, [(12TMC)FeII(NO2 -)]+ (FeII-NO2 -, 2), with variable amounts of H+. FeII-NO2 - upon reaction with one-equiv. of acid (H+) generates [(12TMC)Fe(NO)]2+, {FeNO}7 (3) with H2O2 rather than H2O. However, the amount of H2O2 decreases with increasing equivalents of H+ and entirely disappears when H+ reaches ≅ two-equiv. and shows H2O formation. Furthermore, we have spectroscopically characterized and followed the formation of H2O2 (H+ = one-equiv.) and H2O (H+ ≅ two-equiv.) and explained why bio-driven NiR reactions end with NO and H2O. Mechanistic investigations, using 15N-labeled-15NO2 - and 2H-labeled-CF3SO3D (D+ source), revealed that the N atom in the {Fe14/15NO}7 is derived from the NO2 - ligand and the H atom in H2O or H2O2 is derived from the H+ source, respectively.

Large eddy simulation (LES) of supersonic compressible turbulent flow in a circular pipe at moderate friction Reynolds number and supersonic Mach number with isothermal wall is performed. An explicit filtering approach based on approximate deconvolution method is used for LES. The present LES results agree reasonably well with recent DNS results of compressible pipe flow at similar Mach and Reynolds numbers.

Abstract Purpose None of the previous studies established a strong relationship between them. Thus, the aim of the present pilot research was to evaluate the detailed visual functions and qualitative and quantitative OCT parameters and to measure the correlation between them. Methods Patients diagnosed as naïve neovascular AMD were recruited from a public hospital of Malaysia. Best corrected distance visual acuity, near visual acuity, reading speed and contrast sensitivity were assessed. Several quantitative and qualitative morphological parameters were evaluated using the spectral-domain OCT. A semi auto method of image analysis was employed. Results Fifteen newly diagnosed typical neovascular AMD eyes were evaluated in this study. Mean (± SD) distance visual acuity, near visual acuity, contrast sensitivity and reading speed were recorded as 0.92 ± 0.39, 0.80 ± 0.38, 0.75 ± 0.39, 70.02 ± 14 respectively. Average retinal thickness, central thickness and centre maximum thickness showed good correlation (r = > 0.05) with distance visual acuity, near visual acuity and contrast sensitivity. Similarly, centre minimum thickness showed good correlation (r = > 0.50) with distance visual acuity. An intact external limiting membrane and photoreceptors inner and outer segment showed better visual functions. Conclusion The present pilot study reported morphological and visual functions of Malaysian typical neovascular AMD eyes. All the visual functions of the study eyes showed significant impairment. Some of the OCT parameters showed good correlation with visual functions. Thus, regardless of small sample size, the present pilot study generated new knowledge and understanding on this area. Future research with large sample is recommended.

Here, we report the nitric oxide dioxygenation (NOD) reactions of two MnIII-peroxo (MIII-O22-) complexes, [(3PYENMe)MnIII(O22-)]+ (1) and [(N3PY)MnIII(O22-)]+ (2), bearing pentadentate ligands. Complexes 1 and 2 give MnII-nitrate (MnII-NO3-) complexes (3 and 4) when reacted with nitric oxide (NO), respectively. The mechanistic study explored by using 2,4-di-tert-butylphenol (2,4-DTBP) suggested that the NOD reaction of 1 and 2 occurs via a presumed Mn-peroxynitrite ([Mn-PN]+, [Mn-ONOO-]+) intermediate. Tracking the source of N atoms using 15NO revealed that the N-atoms in MnII-NO3- (3 and 4) are derived from the 15NO moiety. Furthermore, we have explored the MIII-O22- regeneration from NOD products (3 and 4), and we have observed the formation of MIII-O22- complexes (1 and 2) upon treatment with KO2 or H2O2/triethylamine (TEA), respectively.

Direct numerical simulation of a compressible round jet is carried out at Mach number of 0.9 and Reynolds number of 3600 and the data are used to perform velocity gradient tensor (VGT) analysis for different regions of the spatially developing jet. For the developed portion of the jet, the classical teardrop shape is observed for the joint probability density function (p.d.f.) of Q and R (second and third invariants of the VGT). In the region just after the potential core, between $X = 10$ and 15 $r_0$ ( $r_0$ is the jet inlet radius), an inclination towards the third quadrant is observed in the Q – R joint p.d.f. which represents the presence of tube-like structures. It is also shown that this inclination in the turbulent/non-turbulent (T/NT) boundary and interface towards the third quadrant is mainly a contribution of points that lie in regions with negative dilatation. Regions with weak expansion also show this third quadrant inclination to some extent. Points that lie in regions with relatively higher positive dilatation show no such inclination towards the third quadrant but are inclined towards the fourth quadrant which indicates the presence of sheet-like structures. Similarly for the domain segment $X = 15$ to 20 $r_0$ , it is observed that points that lie in the regions with positive dilatation have a joint p.d.f. with an inclination towards fourth quadrant, which suggests the presence of sheet-like structures at the T/NT boundary and interface. Points that lie in regions with negative dilatation show the appearance of a third quadrant lobe.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Introduction: Amblyopia is a condition with reduced best corrected visual acuity in absence of any ocular pathology. Different treatment approaches of amblyopia have been researched for decades. Recent studies on binocular dichoptic therapy using different software and video game based training showed drastic improvement in visual functions in amblyopic adults. Aim of this review is to assess the effect of vision therapy with dichoptic training in adults with anisometropic amblyopes. Method: Review was conducted in articles published within last 25 years from databases like PubMed, research gate, google scholar. Results: Dichoptic therapy has promising results in treatment of adults with anisometropic amblyopia. However, several limitations of these said researches were observed. Conclusion: Further studies particularly RCTs with strict methodology and treatment protocol, larger sample size and longer follow ups are recommended before clinicians could impart dichoptic therapy as a management option of adults with amblyopia into their evidence based practice.

Small molecule activation and their transfer reactions in biological or catalytic reactions are greatly influenced by the metal-centers and the ligand frameworks. Here, we report the metal-directed nitric oxide (NO) transfer chemistry in low-spin mononuclear {Co(NO)}8, [(12-TMC)CoIII(NO−)]2+ (1-CoNO, S = 0), and {Cr(NO)}5, ([(BPMEN)Cr(NO)(Cl)]+) (4-CrNO, S = 1/2) complexes. 1-CoNO transfers its bound NO moiety to a high-spin [(BPMEN)CrII(Cl2)] (2-Cr, S = 2) and generates 4-CrNOvia an associative pathway; however, we did not observe the reverse reaction, i.e., NO transfer from 4-CrNO to low-spin [(12-TMC)CoII]2+ (3-Co, S = 1/2). Spectral titration for NO transfer reaction between 1-CoNO and 2-Cr confirmed 1 : 1 reaction stoichiometry. The NO transfer rate was found to be independent of 2-Cr, suggesting the presence of an intermediate species, which was further supported experimentally and theoretically. The experimental and theoretical observations support the formation of μ-NO bridged intermediate species ({Cr–NO–Co}4+). Mechanistic investigations using 15N-labeled-15NO and tracking the 15N-atom established that the NO moiety in 4-CrNO is derived from 1-CoNO. Further, to investigate the factors deciding the NO transfer reactivity, we explored the NO transfer reaction between another high-spin CrII-complex, [(12-TMC)CrII(Cl)]+ (5-Cr, S = 2), and 1-CoNO, showing the generation of the low-spin [(12-TMC)Cr(NO)(Cl)]+ (6-CrNO, S = 1/2); however, again there was no opposite reaction, i.e., from Cr-center to Co-center. The above results advocate clearly that the NO transfer from Co-center generates thermally stable and low-spin and inert {Cr(NO)}5 complexes (4-CrNO & 6-CrNO) from high-spin and labile Cr-complexes (2-Cr & 5-Cr), suggesting a metal-directed NO transfer (cobalt to chromium, not chromium to cobalt). These results explicitly highlight that the NO transfer is strongly influenced by the labile/inert behavior of the metal-centers and/or thermal stability rather than the ligand architecture.

Compressible turbulent flow through canonical convergent-divergent nozzles with circular cross-section, isothermal walls, with and without bell-shaped divergent portion is investigated by means of Direct numerical simulations. The goal of the present study is to demonstrate the effects of flow expansion (and local flow compression) in these nozzles, which have substantial transonic regions, on the mean flow and the turbulence structure. The efficacy of the kinematic or incompressible displacement thickness as a possible lengthscale for computing nondimensional pressure gradient parameters which are indicators of self-similar regions in these flows is shown. Elongation of near-wall flow structures and the dominance of vortex stretching as local flow topology are found in regions of expansion. This is accompanied by a decrease in Reynolds stresses. Regions of local flow compression are found in the divergent portion of the bell-shaped nozzle where vortex compression is the dominant flow topology. A local increase in the streamwise Reynolds stress is found in this region.

The objective of this study was to compare visual parameters and retinal layers' morphology pre-treatment (baseline) and 6 months post-treatment in polypoidal choroidal vasculopathy (PCV) eyes. A single centre, longitudinal, prospective study was conducted at a public tertiary hospital of Malaysia. Visual parameters including distance and near visual acuity (DVA and NVA), contrast sensitivity (CS), reading speed (RS), and different qualitative and quantitative optical coherence tomography (OCT) parameters were evaluated pre- and 6 months post-treatment. Thirty-three naïve PCV eyes of 32 patients (mean age of 67.62 years) were evaluated pre- and post-treatment of intravitreal ranibizumab with and without photodynamic therapy. After treatment, sub retinal fluid decreased from 27 eyes (84.35%) at baseline to 7 eyes (21.88%) at 6 months while pigment epithelium detachment decreased from 32 eyes (100%) at base line to 15 eyes (46.87%) at 6 months. Mean pre-treatment quantitative morphological OCT retinal parameters including thickness and volume of central sub field, center thickness, center minimum, and maximum thickness reduced significantly. Similarly, all visual parameters including DVA, NVA, CS, and RS showed statistically significant improvement. While 89% of the eyes showed improvement in CS, 78%, 71%, and 65% of the eyes showed improvement in NVA, RS, and DVA, respectively. Thus, CS was the most treatment responsive visual parameter.