Calorimetric, optical and dielectric measurements on two Schiff's based liquid crystalline materials exhibiting multiple phase transitions.

We report high-resolution calorimetric, optical and dielectric studies on two Schiff's based liquid crystalline materials, 4O.5 and 5O.5, which exhibit multiple phase transitions. The study goes beyond the commonly studied isotropic-to-nematic (I-N) and nematic-to-smectic A (N-SmA) phase transitions and explores higher-order smectic phase transitions. The critical exponent, α values, for different phase transitions has been explored. For the I-N, N-SmA, SmA-SmC, SmC-SmF, SmF-CrG and SmB-CrG transitions, α values close to 0.5 and amplitude ratios A-/A+ ~ 1.6 and D-/D+ ~ 1 indicate a first-order nature. Notably, for the SmA-SmB transition, although α (≈ 0.64) is larger than the tricritical value of 0.5, A-/A+ ~ 1.2 and D-/D+ ~ 1, and the study reports an order parameter critical exponent (ß) of 0.26 ± 0.002, which supports a tricritical nature for this transition. Importantly, the ratios of A-/A+ and D-/D+ are found to have similar values across all three-measurement methods, indicating consistency and agreement among these methods.

Genetic Diversity and Anti-Oxidative Potential of Streptomyces spp. Isolated from Unexplored Niches of Meghalaya, India.

Streptomyces is genetically and functionally diverse genus known to produce a wide array of phenolics and flavonoids with significant biotechnological applications. 52 isolates belonging to 26 species of Streptomyces collected from Meghalaya, India were analyzed for their genetic diversity using BOX-PCR. Significant inter- and intra- generic diversity was observed among the Streptomyces isolates especially those belonging to S. cacaoi, S. lavendulae, S. olivochromogenes, S. aureus, S. flavovirens. During bioactivity screening of the isolates, S. rectiviolaceus MJM72 recorded the highest DPPH activity (77.13 ± 0.91%) whereas S. antimycoticus MSCA162 showed excellent ABTS radical scavenging activity (99.65 ± 0.41%). On the other hand, S. novaecaesareae MJM58 had the highest (756.4 ± 7.38 µg GAE g-1 fresh weight) phenolic content while S. rectiviolaceus MJM72 was recorded with the highest flavonoid content (69.3 ± 0.12 µg QE g-1 fresh weight). As compared to total flavonoid content, total phenolic content had a stronger correlation with antioxidant activities. HPLC analysis of five selected isolates showed presence of gallic acid and pyrocatechol as predominant phenolics. In case of flavonoids, three isolates showed presence of rutin with S. rochei MSCA130 having the highest rutin content (0.95 µg g-1 fresh weight). The results of this study showed high genetic diversity and antioxidant potential among the Streptomyces isolates.

Ramifications of Vorticity on Aggregation and Activation of Platelets in Bi-Leaflet Mechanical Heart Valve: Fluid-Structure-Interaction Study.

Bileaflet mechanical heart valves (BMHV) are widely implanted to replace diseased heart valves. Despite many improvements in design, these valves still suffer from various complications, such as valve dysfunction, tissue overgrowth, hemolysis, and thromboembolism. Thrombosis and thromboembolism are believed to be initiated by platelet activation due to contact with foreign surfaces and nonphysiological flow patterns. The implantation of the valve causes nonphysiological patterns of vortex shedding behind the leaflets. This study signifies the importance of vorticity in platelet activation and aggregation in BMHV implants. A two-phase model with the first Eulerian phase for blood and the second discrete phase for platelets is used here. The generalized cross model of viscosity has been used to simulate the non-Newtonian viscosity of blood. A fluid-structure-interaction model has been used to simulate the motion of leaflets. This study has also estimated the platelet activation state (PAS), which is the mathematical estimation of the degree of activation of platelets due to flow-induced shear stresses that cause thrombus formation. The regions in the fluid domain with a higher vorticity field have been found to contain platelets with relatively higher PAS than regions with relatively lower vorticity fields. Also, this study has quantitatively reported the effect of vorticity on platelet aggregation. Platelet densities in fluid areas with higher vorticity are higher than densities in fluid areas with lower vorticity, indicating that highly activated platelets aggregate in areas with stronger vorticity.

Measurement of visco-elastic properties in a binary system of hockey stick-shaped and calamitic mesogens.

Temperature variation of the splay elastic modulus (K11) and rotational viscosity ([Formula: see text]) have been measured throughout the entire nematic (N phase of a binary liquid crystal system comprising of host calamitic compound, 4'-octyloxy-4-cyanobiphenyl (8OCB) and small amount of a hockey stick-shaped mesogen, 4-(3-decyloxyphenyliminomethyl) phenyl 4-decyloxycinnamate (SF7). Two different structural conformations play a significant role in the phase behavior leading to a noticeable shrinkage in the nematic width. During cooling in the nematic phase, both K11 and [Formula: see text] enhance monotonically and divulge an evidence of pretransitional fluctuation near the Smectic-A (Sm-A) transition. With increase in the dopant concentration, the slope of the temperature-dependent K11 and [Formula: see text] becomes uniformly steeper. The observed variations are explained in accordance with the formation of smectic-like clusters in the nematic phase. A representative model of the smectic-like clusters in the nematic phase is presented. However, the obtained values of [Formula: see text] have found to be between that of conventional calamitics and typical bent-core mesogens. Measurement of the temperature-dependent orientational order parameter (〈P2〉 ) and activation energy (Ea) has also been carried out for all the studied mixtures, exhibiting a small augmentation due to the addition of a hockey stick-shaped compound. This indicates an enhancement in intermolecular packing within the mixtures which further influences the molecular motions.

Influence of Co2+ Ions on the Microstructure and Mechanical Properties of Ni-W/Diamond Nano-Composite Coatings.

The Co were incorporated into the Ni-W/diamond nano-composite coatings by introducing CoSO4 in the aforesaid plating bath. The effects of the Co content in the electrodeposit on microstructure and mechanical properties were analyzed. The morphology and the composition of the deposits were investigated by means of SEM and EDS, respectively. The Co content in the coatings increases progressively upon increasing the amount of CoSO4 in the plating bath. The addition of small amount of CoSO4 in the plating bath tends to enhance the hardness and wear performance of the Ni-W/diamond nano-composite coatings. While the amount of CoSO4 beyond 0.2 g/L in the plating bath, the hardness and the wear resistance of the coatings decrease sharply.

Identification, characterization and gene expression analyses of important flowering genes related to photoperiodic pathway in bamboo.

BACKGROUND: Bamboo is an important member of the family Poaceae and has many inflorescence and flowering features rarely observed in other plant groups. It retains an unusual form of perennialism by having a long vegetative phase that can extend up to 120 years, followed by flowering and death of the plants. In contrast to a large number of studies conducted on the annual, reference plants Arabidopsis thaliana and rice, molecular studies to characterize flowering pathways in perennial bamboo are lacking. Since photoperiod plays a crucial role in flower induction in most plants, important genes involved in this pathway have been studied in the field grown Bambusa tulda, which flowers after 40-50 years. RESULTS: We identified several genes from B. tulda, including four related to the circadian clock [LATE ELONGATED HYPOCOTYL (LHY), TIMING OF CAB EXPRESSION1 (TOC1), ZEITLUPE (ZTL) and GIGANTEA (GI)], two circadian clock response integrators [CONSTANS A (COA), CONSTANS B (COB)] and four floral pathway integrators [FLOWERING LOCUS T1, 2, 3, 4 (FT1, 2, 3, 4)]. These genes were amplified from either gDNA and/or cDNA using degenerate as well as gene specific primers based on homologous sequences obtained from related monocot species. The sequence identity and phylogenetic comparisons revealed their close relationships to homologs identified in the temperate bamboo Phyllostachys edulis. While the four BtFT homologs were highly similar to each other, BtCOA possessed a full-length B-box domain that was truncated in BtCOB. Analysis of the spatial expression of these genes in selected flowering and non-flowering tissue stages indicated their possible involvement in flowering. The diurnal expression patterns of the clock genes were comparable to their homologs in rice, except for BtZTL. Among multiple BtCO and BtFT homologs, the diurnal pattern of only BtCOA and BtFT3, 4 were synchronized in the flower inductive tissue, but not in the non-flowering tissues. CONCLUSION: This study elucidates the photoperiodic regulation of bamboo homologs of important flowering genes. The finding also identifies copy number expansion and gene expression divergence of CO and FT in bamboo. Further studies are required to understand their functional role in bamboo flowering.

Stereoselective Synthesis of Pyrroloisoindolone and Pyridoisoindolone via aza-Prins Cyclization of Endocyclic N-Acyliminium Ions.

A simple methodology has been developed for the synthesis of substituted pyrroloisoindolone and pyridoisoindolone via aza-Prins cyclization of endocyclic N-acyliminium ions, which are derived from the triflic acid treatment of regioselectively reduced N-homopropargyl imides in excellent yields. The reaction is highly diastereoselective, and only one diastereoisomer is formed during the reaction. The methodology can be utilized for the synthesis of pyrimidoisoindole.

Surface modified kokum butter lipid nanoparticles for the brain targeted delivery of nevirapine.

AIM: The present work investigates the efficacy of Polysorbate 80(P80) coated Kokum butter (KB) solid lipid nanoparticles (P80NvKLNs) for the brain targeted delivery of Nevirapine (Nv). METHODS: Solid lipid nanoparticles (SLNs) were prepared by nanoprecipitation technique and evaluated for drug excipient compatibility studies, z- average particle size (nm), zeta potential (mv), percentage drug entrapment efficiency (%EE), surface morphology and in-vitro drug release properties. The in-vivo biodistribution and brain targeting efficiency of nanoparticles were studied in healthy male Wistar rat (150-200 g). RESULTS: P80NvKLNs were found to be smooth surfaced, spherical shaped having average particle size of 177.80 ± 0.82 nm, zeta potential of -8.91 ± 4.36 mv and %EE of 31.32 ± 0.42%. P80NvKLNs remained in blood circulation for 48 h maintaining a sustained release in brain for 24 h (p < 0.05). CONCLUSION: The study proves the efficacy of Polysorbate 80 coated Kokum butter nanoparticles for brain-targeted delivery of drugs providing ample opportunities for further study.

Expression Pattern Similarities Support the Prediction of Orthologs Retaining Common Functions after Gene Duplication Events.

The identification of functionally equivalent, orthologous genes (functional orthologs) across genomes is necessary for accurate transfer of experimental knowledge from well-characterized organisms to others. This frequently relies on automated, coding sequence-based approaches such as OrthoMCL, Inparanoid, and KOG, which usually work well for one-to-one homologous states. However, this strategy does not reliably work for plants due to the occurrence of extensive gene/genome duplication. Frequently, for one query gene, multiple orthologous genes are predicted in the other genome, and it is not clear a priori from sequence comparison and similarity which one preserves the ancestral function. We have studied 11 organ-dependent and stress-induced gene expression patterns of 286 Arabidopsis lyrata duplicated gene groups and compared them with the respective Arabidopsis (Arabidopsis thaliana) genes to predict putative expressologs and nonexpressologs based on gene expression similarity. Promoter sequence divergence as an additional tool to substantiate functional orthology only partially overlapped with expressolog classification. By cloning eight A. lyrata homologs and complementing them in the respective four Arabidopsis loss-of-function mutants, we experimentally proved that predicted expressologs are indeed functional orthologs, while nonexpressologs or nonfunctionalized orthologs are not. Our study demonstrates that even a small set of gene expression data in addition to sequence homologies are instrumental in the assignment of functional orthologs in the presence of multiple orthologs.

Effect of Sodium Dodecyl Sulphate and Sodium Bromide Additives on Ni­W Nanocoatings.

Nickel-tungsten (Ni­W) coatings were fabricated by electrodeposition method with varying quantities of sodium dodecyl sulphate and sodium bromide to examine the effects of the aforesaid additives on the coatings. The obtained nanocoatings were studied by X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, and hardness tester. The hardness, tungsten content and grain size attained a maximum value at current density of 0.15 A/cm²,0.1 A/cm² and 0.1 A/cm², respectively. There was a pronounced impact of both the additives on the microstructure and morphology of the coatings. According to results, there are considerable difference in terms of the impact caused by the additives to the tungsten content, hardness and grain size of the coatings. The obtained results suggest that hardness of coatings is mainly contributed by W content in the deposits.

Sustained Anti-inflammatory Effect of Resveratrol-Phospholipid Complex Embedded Polymeric Patch.

Resveratrol-phospholipid complex (Phytosome®) (RSVP) was found better aqueous soluble and permeable than free resveratrol (RSV). RSVPs were incorporated in polymeric patch prepared by solvent casting method using Eudragit RL 100, PVP K30, and PEG 400 for application on dermal sites for sustained treating of inflammation. Prepared patches were evaluated for various physicochemical properties, surface morphology by SEM, TEM, and compatibility of patch components by FT-IR and DSC studies. Optimized formulation (F9) gave 95.79 ± 3.02% drug release and 51.36% (4.28 ± 0.48 mg/cm2) skin permeation after 24 h. Skin extract when examined for drug accumulation showed 38.31 ± 2.42% drug content. FE-SEM images of the patch taken after drug release and skin permeation studies showed that RSVPs in polymeric patch are stable and retain their structure after 24 h long exposure to physiologic environment. Sustained anti-inflammatory effect was established in carrageenan-induced paw edema model in which test formulation gave 84.10% inhibition of inflammation at 24 h as compared to 39.58% for standard diclofenac sodium gel. The CLSM study confirmed the localization of RSVPs for a longer period, thus enabling drug targeting to the dermis for sustained effect. Skin irritation test on rabbit revealed that the patches are safe for skin application. Histological observations suggested that after exposure to the permeants, the SC integrity had not altered and no evidence of presence of inflammatory cells found. RSVP (Phytosome®) containing patches abled to give sustained therapeutic effect that may be useful in treating acute and chronic inflammation.

Comparative transcriptome analyses reveal core parasitism genes and suggest gene duplication and repurposing as sources of structural novelty.

The origin of novel traits is recognized as an important process underlying many major evolutionary radiations. We studied the genetic basis for the evolution of haustoria, the novel feeding organs of parasitic flowering plants, using comparative transcriptome sequencing in three species of Orobanchaceae. Around 180 genes are upregulated during haustorial development following host attachment in at least two species, and these are enriched in proteases, cell wall modifying enzymes, and extracellular secretion proteins. Additionally, about 100 shared genes are upregulated in response to haustorium inducing factors prior to host attachment. Collectively, we refer to these newly identified genes as putative "parasitism genes." Most of these parasitism genes are derived from gene duplications in a common ancestor of Orobanchaceae and Mimulus guttatus, a related nonparasitic plant. Additionally, the signature of relaxed purifying selection and/or adaptive evolution at specific sites was detected in many haustorial genes, and may play an important role in parasite evolution. Comparative analysis of gene expression patterns in parasitic and nonparasitic angiosperms suggests that parasitism genes are derived primarily from root and floral tissues, but with some genes co-opted from other tissues. Gene duplication, often taking place in a nonparasitic ancestor of Orobanchaceae, followed by regulatory neofunctionalization, was an important process in the origin of parasitic haustoria.

Nanoprecipitation with sonication for enhancement of oral bioavailability of furosemide.

Furosemide is a weakly acidic diuretic indicated for treatment of edema and hypertension. It has very poor solubility but high permeability through stomach and upper gastrointestinal tract (GIT). Due to its limited solubility it has poor and variable oral bioavailibility of 10-90%. The aim of this study was to enhance the oral bioavailibilty of furosemide by preparation of nanosuspensions. The nanosuspensions were prepared by nanoprecipitation with sonication using DMSO (dimethyl sulfoxide) as a solvent and water as an antisolvent (NA). The prepared nanosuspensions were sterically stabilized with polyvinyl acetate (PVA). These were characterized for particle size, zeta potential, polydispersity index, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), X-ray diffraction (XRD) pattern and release behavior. The average particle size of furosemide nanoparticles were found to be in the range of 150-300 nm. This was further confirmed by SEM photograph. The particle size varies with an increase in concentration of drug and stabilizer. The preparations showed negative zeta potential and polydispersity index in the range of 0.3 +/- 0.1. DSC and XRD studies indicated that the crystalline furosemide drug was converted to amorphous form upon precipitation into nanoparticles. The saturation solubility of prepared furosemide nanoparticles markedly increased compared to the original drug in simulated gastric fluid. The release profiles of nanosuspension formulation showed up to 81.2% release in 4 h. It may be concluded that the nanoprecipitation with ultrasonication have potential to formulate homogenous nanosuspensions with uniform sized amorphous nanoparticles of furosemide. Polyvinyl acetate can be used as a suitable steric stabilizer to prepare stable furosemide nanosuspensions. The enhanced saturation solubility in simulated gastric fluid may lead to enhanced absorption of furosemide.

Evolution of a horizontally acquired legume gene, albumin 1, in the parasitic plant Phelipanche aegyptiaca and related species.

BACKGROUND: Parasitic plants, represented by several thousand species of angiosperms, use modified structures known as haustoria to tap into photosynthetic host plants and extract nutrients and water. As a result of their direct plant-plant connections with their host plant, parasitic plants have special opportunities for horizontal gene transfer, the nonsexual transmission of genetic material across species boundaries. There is increasing evidence that parasitic plants have served as recipients and donors of horizontal gene transfer (HGT), but the long-term impacts of eukaryotic HGT in parasitic plants are largely unknown. RESULTS: Here we show that a gene encoding albumin 1 KNOTTIN-like protein, closely related to the albumin 1 genes only known from papilionoid legumes, where they serve dual roles as food storage and insect toxin, was found in Phelipanche aegyptiaca and related parasitic species of family Orobanchaceae, and was likely acquired by a Phelipanche ancestor via HGT from a legume host based on phylogenetic analyses. The KNOTTINs are well known for their unique "disulfide through disulfide knot" structure and have been extensively studied in various contexts, including drug design. Genomic sequences from nine related parasite species were obtained, and 3D protein structure simulation tests and evolutionary constraint analyses were performed. The parasite gene we identified here retains the intron structure, six highly conserved cysteine residues necessary to form a KNOTTIN protein, and displays levels of purifying selection like those seen in legumes. The albumin 1 xenogene has evolved through >150 speciation events over ca. 16 million years, forming a small family of differentially expressed genes that may confer novel functions in the parasites. Moreover, further data show that a distantly related parasitic plant, Cuscuta, obtained two copies of albumin 1 KNOTTIN-like genes from legumes through a separate HGT event, suggesting that legume KNOTTIN structures have been repeatedly co-opted by parasitic plants. CONCLUSIONS: The HGT-derived albumins in Phelipanche represent a novel example of how plants can acquire genes from other plants via HGT that then go on to duplicate, evolve, and retain the specialized features required to perform a unique host-derived function.

Static Permittivity and Electro-Optical Properties of Bi-Component Orthoconic Antiferroelectric Liquid Crystalline Mixtures Targeted for Polymer Stabilized Sensing Systems.

The behavior of two newly formulated bi-component orthoconic antiferroelectric liquid crystalline (OAFLC) systems, i.e., the Compound A + Compound B mixture system and Compound C + Compound B mixture system has been discussed in light of temperature and concentration dependencies of helical pitch length, spontaneous polarization, relaxation time, bulk viscosity, and the anchoring energy strength coefficient, together with static dielectric permittivity (ε) and dielectric anisotropy. Compound A + Compound B mixtures possess spontaneous polarization between 190-340 nC.cm-2 and fast relaxation times between 190-320 µs in the smectic antiferroelectric SmCA* phase at room temperature. Compound C + Compound B mixtures also have a spontaneous polarization in the range of 190-280 nC.cm-2 and relaxation times in the range of 190-230 µs at room temperature. Most of the mixtures have a helical pitch below one micrometer in the SmCA* phase. These advanced mixtures show a broad temperature range of the antiferroelectric SmCA* phase, fast switching of molecules under an applied electric field, negative dielectric anisotropy and a short helical pitch, confirming the advantage of designing new polymer-stabilized OAFLC that is targeted for novel application in sensing devices, utilizing the fast responsive electro-optical modulation elements.

Role of metabolites in flower development and discovery of compounds controlling flowering time.

Flowering is one of the most important physiological processes of plants that ensures continuity of genetic flow from one generation to the next and also maintains food security. Therefore, impact of various climate-related abiotic stresses on flowering have been assessed to evaluate the long-term impact of global climate change. In contrast to the enormous volume of research that has been conducted at the genetic, transcriptional, post-transcriptional, and protein level, much less attention has been paid to understand the role of various metabolites in flower induction and floral organ development during normal growth or in stressed environmental condition. This review article aims at summarizing information on various primary (e.g., carbohydrates, lipids, fatty acid derivatives, protein and amino acids) and secondary metabolites (e.g., polyamines, phenolics, neuro-indoles, phenylpropanoid, flavonoids and terpenes) that have so far been identified either during flower induction or in individual floral organs implying their possible role in organ development. Specialized metabolites responsible for flower colour, scent and shape to support plant-pollinator interaction have been extensively reviewed by many research groups and hence are not considered in this article. Many of the metabolites discussed here may be used as metabolomarkers to identify tolerant crop genotypes. Several agrochemicals have been successfully used to release endodormancy in temperate trees. Along the same line, a strategy that combines metabolite profiling, screening of small-molecule libraries, and structural alteration of selected compounds has been proposed in order to identify novel lead compounds that can regulate flowering time when applied exogenously.

Effect of Pulse Electrodeposition Parameters on the Microstructure and Mechanical Properties of Ni-W/B Nanocomposite Coatings.

In this work, Ni−W/B nanocomposite coatings were successfully fabricated on low carbon steel by using pulse current (PC) electrodeposition. The effects of the frequency and duty cycle on the microstructure, wear resistance, and microhardness of the coatings were studied. The results obtained show that the distribution and content of boron particles (>4 wt.%) in the PC electrodeposition coatings are significantly better than those of direct current (DC) electrodeposition coatings (less than 4 wt.%). The hardness results reveal that the highest microhardness of 1122 HV can be obtained at a frequency of 100 Hz and duty cycle of 30%. Furthermore, the relationship between the microstructure and mechanical properties was discussed.

Sorbitan ester niosomes for topical delivery of rofecoxib.

The aim of the present investigation is to encapsulate rofecoxib in niosomes and incorporate the prepared niosomes into dermal gel base for sustained therapeutic action. Niosomes were prepared by lipid film hydration technique and were analyzed for size, entrapment efficiency and drug retention capacity. Niosomal vesicles were then incorporated into blank carbopol gel to form niosomal gel. The in vitro permeation study across pig skin was performed using Keshary-Chien glass diffusion cell. The size and entrapment efficiency of the niosomal vesicles increased with gradual increase in HLB value of nonionic surfactants used. Maximum drug entrapment was observed with Span 20 with HLB value of 8.6 and drug leakage from vesicles was less at refrigerated condition than at the room temperature. Higher proportion of cholesterol made the niosomal formulation more stable with high drug retention properties. The niosomal gel showed a prolong drug release behavior compared to plain drug gel. Differential scanning calorimetric study of drug loaded gel and pig skin after permeation study confirmed inertness of carbopol gel base toward rofecoxib and absence of drug metabolism in the skin during permeation study, respectively. The niosomal formulations were successfully prepared by lipid film hydration technique using cholesterol and Span as nonionic surfactant. Presence of cholesterol made niosomes more stable with high drug entrapment efficiency and retention properties. The lower flux value of niosomal gel as compared to plain drug gel across pig skin assured the prolong drug release behavior with sustained action.

Effect of foam insertion in aneurysm sac on flow structures in parent lumen: relating vortex structures with disturbed shear.

Numerous studies suggest that disturbed shear, causing endothelium dysfunction, can be related to neighboring vortex structures. With this motivation, this study presents a methodology to characterize the vortex structures. Precisely, we use mapping and characterization of vortex structures' changes to relate it with the hemodynamic indicators of disturbed shear. Topological features of vortex core lines (VCLs) are used to quantify the changes in vortex structures. We use the Sujudi-Haimes algorithm to extract the VCLs from the flow simulation results. The idea of relating vortex structures with disturbed shear is demonstrated for cerebral arteries with aneurysms virtually treated by inserting foam in the sac. To get physiologically realistic flow fields, we simulate blood flow in two patient-specific geometries before and after foam insertion, with realistic velocity waveform imposed at the inlet, using the Carreau-Yasuda model to mimic the shear-thinning behavior. With homogenous porous medium assumption, flow through the foam is modeled using the Forchheimer-Brinkman extended Darcy model. Results show that foam insertion increases the number of VCLs in the parent lumen. The average length of VCL increases by 168.9% and 55.6% in both geometries. For both geometries under consideration, results demonstrate that the region with increased disturbed shear lies in the same arterial segment exhibiting an increase in the number of oblique VCLs. Based on the findings, we conjecture that an increase in oblique VCLs is related to increased disturbed shear at the neighboring portion of the arterial wall.

Assessment and visualization of hemodynamic loading in aneurysm sac and neck: Effect of foam insertion.

Shape memory polymer (SMP) foam is often proposed as the future alternative of coils in aneurysm treatment devices. Present work numerically investigates the unsteady, three-dimensional simulation of blood flow in a cerebral aneurysm filled with SMP foam. Simulations are conducted on patient-specific geometries with realistic blood velocity waveform imposed at the inlet while SMP foam is treated as a porous medium. The present study introduces a "loading risk map" that helps to visualize the hemodynamic effect of foam insertion on the aneurysm sac and neck. The loading risk maps suggest that while the SMP foam subdues the flow and wall shear pulsations in the aneurysm sac, the pressure distribution is minimally affected. The maps suggest that while the downstream lip is the most risk-prone site for both geometries, downstream vascular anatomy significantly influences foam efficiency in reducing pressure and wall shear stress loading.