CO₂/N₂ triggered switchable Pickering emulsions stabilized by alumina nanoparticles in combination with a conventional anionic surfactant

Stable n-decane-in-water Pickering emulsions were prepared using positively charged alumina nanoparticles in combination with a trace amount of the anionic surfactant sodium dodecyl sulfate (SDS) as stabilizer. Particles were hydrophobized in situ by adsorption of surfactant enhancing their surface activity. Emulsions can be readily demulsified by addition of an equal amount of a switchable surfactant, N'-dodecyl-N,N-dimethylacetamidine (DDAA), which can be transformed between a surface-active amidinium/cationic form and a surface-inactive amidine/neutral form by bubbling CO₂ or N₂, respectively. Following addition of cationic DDAA which prefers to form ion pairs with SDS, desorption of SDS from particles surfaces occurs and alumina particles are rendered hydrophilic resulting in demulsification of the emulsion. However, by bubbling N₂ into the demulsified mixture, DDAA molecules are converted to the amidine/neutral form leading to collapse of the ion pairs and re-establishment of the in situ hydrophobization of particles. Stable Pickering emulsions can be prepared again following homogenization. This simple demulsification/re-stabilization cycle can be repeated several times. Experimental evidence including measurement of the adsorption isotherm, zeta potentials, extent of particle adsorption at droplets interfaces in emulsions and microscopy is given to support the postulated mechanisms

Oxygen Ion Escape at Venus Associated With Three-Dimensional Kelvin-Helmholtz Instability

How oxygens escape from Venus has long been a fundamental but controversial topic in the planetary research. Among various key mechanisms, the Kelvin-Helmholtz instability (KHI) has been suggested to play an important role in the oxygen ion escape from Venus. Limited by either scarce in-situ observations or simplified theoretical estimations, the mystery of oxygen ion escape process associated with KHI is still unsettled. Here we present the first three-dimensional configuration of KHI at Venus with a global multifluid magnetohydrodynamics model, showing a significantly fine structure and evolution of the KHI. KHI mainly occurred at the low latitude boundary layer if defining the interplanetary magnetic field-perpendicular plane as the equatorial plane, resulting in escaping oxygen ions through mixing with the solar wind at the Venusian boundary layer, with an escape rate around 4 × 1024 s−1. The results provide new insights into the basic physical process of atmospheric loss at other unmagnetized planet

Phylogenetic analysis of porcine circovirus 3 circulating in Canadian pigs

Introduction: Porcine circovirus 3 (PCV3) has been detected in pigs worldwide and associated with several clinical signs. Methods: To investigate the genetic diversity of PCV3 strains circulating in Canada, 44 PCV3 positive samples from Saskatchewan (2/44), Manitoba (2/44), Quebec (4/44), Alberta (11/44) and Ontario (25/44) submitted to diagnostic laboratories in Canada between 2019 and 2021 were sequenced and analyzed. Results: Phylogenetic analysis of capsid genes showed that all of the 44 Canadian strains classified into PCV3a and segregated into seven lineages with common amino acid changes observed at A24V, R27K, N56D, T77S, Q98R, L150I (F) and R168K positions. Conclusion: Future studies are required to determine whether the polymorphisms in capsid proteins, as revealed in this study, could be associated with differences in the pathogenicity or antigenicity of PCV3 strains. This is the first phylogenetic analysis of PCV3 strains among different provinces in Canada

Nitrogen availability prevents oxidative effects of salinity on wheat growth and photosynthesis by up-regulating the antioxidants and osmolytes metabolism, and secondary metabolite accumulation.

Funder: NorthWest A&F University Yaangling, Shaanxi, China.BACKGROUND: Salinity is one of the damaging abiotic stress factor. Proper management techniques have been proposed to considerably lower the intensity of salinity on crop growth and productivity. Therefore experiments were conducted to assess the role of improved nitrogen (N) supplementation on the growth and salinity stress tolerance in wheat by analyzing the antioxidants, osmolytes and secondary metabolites. RESULTS: Salinity (100 mM NaCl) stress imparted deleterious effects on the chlorophyll and carotenoid synthesis as well as the photosynthetic efficiency. N supplementation resulted in increased photosynthetic rate, stomatal conductance and internal CO2 concentration with effects being much obvious in seedlings treated with higher N dose. Under non-saline conditions at both N levels, protease and lipoxygenase activity reduced significantly reflecting in reduced oxidative damage. Such effects were accompanied by reduced generation of toxic radicals like hydrogen peroxide and superoxide, and lipid peroxidation in N supplemented seedlings. Antioxidant defence system was up-regulated under saline and non-saline growth conditions due to N supplementation leading to protection of major cellular processes like photosynthesis, membrane structure and function, and mineral assimilation. Increased osmolyte and secondary metabolite accumulation, and redox components in N supplemented plants regulated the ROS metabolism and NaCl tolerance by further strengthening the antioxidant mechanisms. CONCLUSIONS: Findings of present study suggest that N availability regulated the salinity tolerance by reducing Na uptake and strengthening the key tolerance mechanisms

Engineered zero-dispersion microcombs using CMOS-ready photonics

Normal group velocity dispersion (GVD) microcombs offer high comb line power and high pumping efficiency compared to bright pulse microcombs. The recent demonstration of normal GVD microcombs using CMOS-foundry-produced microresonators is an important step towards scalable production. However, the chromatic dispersion of CMOS devices is large and impairs generation of broadband microcombs. Here, we report the development of a microresonator in which GVD is reduced due to a couple-ring resonator configuration. Operating in the turnkey self-injection-locking mode, the resonator is hybridly integrated with a semiconductor laser pump to produce high-power-efficiency combs spanning a bandwidth of 9.9 nm (1.22 THz) centered at 1560 nm, corresponding to 62 comb lines. Fast, linear optical sampling of the comb waveform is used to observe the rich set of near-zero GVD comb behaviors, including soliton molecules, switching waves (platicons) and their hybrids. Tuning of the 20 GHz repetition rate by electrical actuation enables servo locking to a microwave reference, which simultaneously stabilizes the comb repetition rate, offset frequency and temporal waveform. This hybridly integrated system could be used in coherent communications or for ultra-stable microwave signal generation by two-point optical frequency division.Comment: 8 pages, 4 figure

In Vivo Delivery of Gremlin siRNA Plasmid Reveals Therapeutic Potential against Diabetic Nephropathy by Recovering Bone Morphogenetic Protein-7

Diabetic nephropathy is a complex and poorly understood disease process, and our current treatment options are limited. It remains critical, then, to identify novel therapeutic targets. Recently, a developmental protein and one of the bone morphogenetic protein antagonists, Gremlin, has emerged as a novel modulator of diabetic nephropathy. The high expression and strong co-localization with transforming growth factor- β1 in diabetic kidneys suggests a role for Gremlin in the pathogenesis of diabetic nephropathy. We have constructed a gremlin siRNA plasmid and have examined the effect of Gremlin inhibition on the progression of diabetic nephropathy in a mouse model. CD-1 mice underwent uninephrectomy and STZ treatment prior to receiving weekly injections of the plasmid. Inhibition of Gremlin alleviated proteinuria and renal collagen IV accumulation 12 weeks after the STZ injection and inhibited renal cell proliferation and apoptosis. In vitro experiments, using mouse mesangial cells, revealed that the transfect ion of gremlin siRNA plasmid reversed high glucose induced abnormalities, such as increased cell proliferation and apoptosis and increased collagen IV production. The decreased matrix metalloprotease level was partially normalized by transfection with gremlin siRNA plasmid. Additionally, we observed recovery of bone morphogenetic protein-7 signaling activity, evidenced by increases in phosphorylated Smad 5 protein levels. We conclude that inhibition of Gremlin exerts beneficial effects on the diabetic kidney mainly through maintenance of BMP-7 activity and that Gremlin may serve as a novel therapeutic target in the management of diabetic nephropathy