PEGylation of Nanoemulsion Using Spontaneous Emulsification Method.

Nanoemulsion (NE), a lipid-based drug delivery system, plays an important role in delivering drugs and enhancing bioavailability. They are mainly taken up by the reticuloendothelial system, because of which their bioavailability is diminished, leading to poor therapeutic activity. It is important to protect this delivery system using a coating agent. Thus, we have coated o/w type NE using polyethylene glycol (PEG). The novelty in our study is use of dicarboxylic acid-linked PEG. Furthermore, the spontaneous emulsification method was used in preparation and peg coating, not mentioned previously. After the preparation of NE, various characterization and stability studies were carried out. We have also optimized the ratios for NE and PEG NE by using various concentrations of Smix, PEG, and water. Also, the same has also been plotted in a pseudoternary-phase diagram. As a conclusion, the PEGylation of NE was carried out successfully and may also be used for linking with other ligands because of the presence of COOH group.

Surgical Management of Dystocia Due to Unilateral Uterine Torsion in a Domestic Shorthair Cat.

A 2-year-old pluriparous domestic shorthair queen was brought to the Madras Veterinary College Teaching hospital with a history of full-term pregnancy, straining for the past 24 hours and brown vaginal discharge. Radiography of the abdomen showed presence of 3 fetal skeletons, and ultrasonography revealed no fetal heartbeat. An emergency caesarean section was performed, and a 720° torsion of the right uterine horn was revealed. Three dead kittens were delivered, 2 from the right horn and 1 from the left horn. An ovariohysterectomy was also performed.

Study of luminescence and effect of Dy3+ on NaMgSO4 Cl:Ce chlorosulphate phosphor.

Chlorosulphate NaMgSO4 Cl phosphor doped with Ce(3+) and co-doped by Dy(3+) prepared by the wet chemical method was studied for its photoluminescence and thermoluminescence (TL) characteristics. The emission spectrum of Ce(3+) shows dominant peaks at 346 nm (excitation 270 nm) due to 5d → 4f transition. Efficient energy transfer occurs from Ce(3+) → Dy(3+) ions. Dy(3+) emission at 485 nm and 576 nm is due to (4) F9/2 → (6) H15/2 and (4) F9/2 → (6) H13/2 transitions of Dy(3+) ion respectively. The TL glow curves of NaMgSO4 Cl:Ce and Ce,Dy have been recorded for various concentrations at a heating rate of 2 °C/s irradiated by γ-rays at a dose rate of 0.995 kGy/h for 1 Gy, which peaks at about 241 °C and 247-312 °C respectively. Further, in changing the concentration level, the general structure of the intensity is found to increase. The main property of this phosphor is its sensitivity even for low concentrations of rare earth ions and low γ-ray dose. There is still scope for higher doses of γ-radiation. The phosphor presented may be used as a lamp phosphor as well as for TL studies.

Biodegradable polymer based encapsulation of neem oil nanoemulsion for controlled release of Aza-A.

Azadirachtin a biological compound found in neem have medicinal and pesticidal properties. The present work reports on the encapsulation of neem oil nanoemulsion using sodium alginate (Na-Alg) by cross linking with glutaraldehyde. Starch and polyethylene glycol (PEG) were used as coating agents for smooth surface of beads. The SEM images showed beads exhibited nearly spherical shape. Swelling of the polymeric beads reduced with coating which in turn decreased the rate of release of Aza-A. Starch coated encapsulation of neem oil nanoemulsion was found to be effective when compared to PEG coated encapsulation of neem oil nanoemulsion. The release rate of neem Aza-A from the beads into an aqueous environment was analyzed by UV-visible spectrophotometer (214 nm). The encapsulated neem oil nanoemulsion have the potential for controlled release of Aza-A. Neem oil nanoemulsion encapsulated beads coated with PEG was found to be toxic in lymphocyte cells.

ApoE4 and late onset depression in Indian population.

OBJECTIVE: ApoE4 is a 'risk factor' for cognitive disorders like Alzheimer's dementia, and Late Onset Depression (LOD) is a forerunner of dementia. There is thus a need to study the association between ApoE4 allele and LOD. METHOD: The study assessed the frequency of ApoE4 allele in 31 cases of LOD above the age of 50 years and 31 matched controls. The subjects were assessed on various clinical parameters towards diagnosis. RESULTS: There was a significant association between the ApoE4 allele and LOD in comparison to controls (Odd's ratio=4.7, Confidence Interval=1.12 to 19.79, P=0.035). ApoE4 allele had no association with the age of onset of depression, cognitive functions and severity of LOD. CONCLUSION: Individuals with LOD have a significantly higher frequency of the ApoE4 allele. In other words, elderly in India with an ApoE4 allele have 4.7 times more risk of developing depression in old age. Within LOD group there is no difference between those with and without ApoE4 accordingly in age of onset of depression, cognitive functions and severity of LOD.

Which obese children should have a sleep study?

BACKGROUND: The UK government has recommended the development of obesity services for children. As obesity is common, studying every obese child for obstructive sleep apnoea (OSA) would be challenging and full paediatric sleep services are not available in every area in Europe. The purpose of this study was to consider how well clinical features predict significant OSA in obese children in order to help prioritise the need for sleep studies and subsequent treatment. METHODS: Consecutive children referred for obesity management aged 2-16 years with a body mass index (BMI) of >2.5 z scores for age were offered a sleep study using overnight oximetry and audiovisual recordings. Significant OSA was defined as > or = 5 dips/h of >4% oxygen saturation or > or = 5 respiratory-event related arousals/h. RESULTS: Forty-one of 158 (26%) children (mean BMI z score 3.7) had significant OSA and 95% of these had either reported apnoea, restless sleep or tonsillar hypertrophy (TH). Nineteen percent of all children had none of these features. BMI was not related to OSA. CONCLUSION: If only obese children with reported apnoea, restless sleep or TH have a sleep study, 95% of all obese children with significant OSA will be identified using this method.

Dynamics of hairpin vortices and polymer-induced turbulent drag reduction.

It has been known for over six decades that the dissolution of minute amounts of high molecular weight polymers in wall-bounded turbulent flows results in a dramatic reduction in turbulent skin friction by up to 70%. First principles simulations of turbulent flow of model polymer solutions can predict the drag reduction (DR) phenomenon. However, the essential dynamical interactions between the coherent structures present in turbulent flows and polymer conformation field that lead to DR are poorly understood. We examine this connection via dynamical simulations that track the evolution of hairpin vortices, i.e., counter-rotating pairs of quasistreamwise vortices whose nonlinear autogeneration and growth, decay and breakup are centrally important to turbulence stress production. The results show that the autogeneration of new vortices is suppressed by the polymer stresses, thereby decreasing the turbulent drag.

Pattern formation in Taylor-Couette flow of dilute polymer solutions: dynamical simulations and mechanism.

We report spatiotemporal pattern formation in Taylor-Couette flow (i.e., flow between rotating cylinders) of viscoelastic dilute polymer solutions obtained for the first time from first-principles dynamical simulations. Solution structures with varying spatial and temporal symmetries, such as rotating standing waves, flames, disordered oscillations, and solitary vortex solutions which include diwhirls (stationary and axisymmetric) and oscillatory strips (axisymmetric or nonaxisymmetric), are observed, depending on the ratio of fluid relaxation time to the time period of inner cylinder rotation. The flow-microstructure coupling mechanisms underlying the pattern formation process are also discussed.

Hierarchical approach to model multilayer colloidal deposition in porous media.

Particle deposition is important in many environmental systems such as water and wastewater filtration, air pollution control, subsurface transport, biofilm formation and fouling, and thin film synthesis for use in remediation technologies. While continuum-level models have been developed to predict deposition dynamics in these systems, these models fail to explain transient dynamics of multilayer deposition from a mechanistic viewpoint. In this work, a multiscale approach has been developed to predict multiple layer irreversible colloidal deposition in the presence of interparticle electrostatic and van der Waals interactions in porous media. The approach combines the kinetic information obtained from the mesoscopic stochastic simulations of particle deposition with the macroscopic conservation equation describing colloidal transport. Sequential Brownian dynamics simulations are first performed by accounting for particle-particle (P-P) and particle-surface (P-S) interactions, and multilayered particle deposits are obtained. The available surface function quantifying the deposition kinetics is then obtained from the deposit microstructure. Deposition dynamics are studied at different ionic strengths and particle potentials that control the range and magnitude of interparticle interactions. Simulation results showed that the microstructure of the particle deposits formed under the influence of P-P and P-S electrostatic interactions exhibited significant variations with respect to ionic strength and could be qualitatively explained bythe interplay between the repulsive and attractive P-P and P-S interaction forces. The available surface function also varied significantly as a function of ionic strength. This basic understanding of the deposition dynamics at the mesoscale was then combined with the continuum-level transport equations to predict particle breakthrough curves in porous media. The approach is capable of capturing transient features of deposition dynamics, as demonstrated by the good agreement between the model predictions and the experimental observations.

Multiscale simulation of irreversible deposition in presence of double layer interactions.

Sequential lattice Monte Carlo simulations, in which the transition probabilities are derived from the discrete form of the continuum-level mass conservation law, are used to predict the morphology of colloidal deposits. The simulations account for particle-surface (P-S) and particle-particle (P-P) electrostatic and van der Waals interactions. Simulation results for maximum coverage for monolayer deposition are in quantitative agreement with the hard-sphere RSA jamming limit. Moreover, as reported in earlier studies, monolayer simulations in the absence of P-S interactions qualitatively predict the monotonic increases in fractional coverage with increasing ionic strength, characterized by the Debye screening length (kappa a). Monolayer simulations with P-S interactions show that the dependence of fractional coverage on kappa a is strongly influenced by the ratio of particle to surface potentials (Psi(p)/Psi(s)). P-S and P-P forces achieve their respective maximum at different values of kappa a leading to a nonmonotonic trend in surface coverage as a function of kappa a. These results indicate that the incorporation of P-S interactions into colloidal deposition studies allows more accurate interpretation of the experimental data. In multilayer deposition simulations, balance between long-ranged weak interactions and short-ranged strong interactions between P-P and P-S, coupled with physical screening effects, resulted in widely varying coverages with height of the deposit, ionic strength, and Psi(p)/Psi(s). Moreover, fractal dimension of the deposit ranged from approximately 1 (kappa a << 1) to 1.7 (kappa a >> 1). Qualitative kinetic analysis showed widely varying deposition rates in different layers depending on Psi(p)/Psi(s) and ionic strength. The multilayer system approached the monolayer system in the limit kappa a--> infinity and Psi(p)/Psi(s)--> infinity.

Bioactivity and osseointegration study of calcium phosphate ceramic of different chemical composition.

Synthetic hydroxyapatite (HA) and tricalcium phosphate (TCP) are promising bone-substitute materials in the orthopaedic and dental fields, as their chemical composition is similar to that of bone. This study investigated the osseointegration performance of carbonated biphasic calcium phosphate (CBCP) ceramics containing carbonated hydroxyapatite and tricalcium phosphate prepared by microwave irradiation, in femoral defects of dogs. The defects were created as 3-mm holes on the lateral aspect of femur and filled with the implant material. The serum was collected postoperatively and biochemical assays for alkaline phosphatase activity levels were carried out. The animals' defective sites were radiographed at 4, 8, and 12 weeks. The radiographic results showed that the process of ossification started after 4 weeks and the defect was completely filled with new bone after 8 weeks. Histological examination of the tissue showed the osteoblastic activity inducing the osteogenesis in the defect. The complete haversian system with osteoblastic and osteoclastic activity and bone remodelling process were observed after 12 weeks. The alkaline phosphatase activity levels also correlated with the formation of osteoblast cells. This calcium phosphate ceramic has proved to work well as a biocompatible implant and as an osteoconductive and osteoinductive material for the filling of bone defects.