Anti-inflammatory activity of Pseudopterosins by laser doppler blood flow evaluation

IFSCC Magazines , 12 (2009) (1) 25–30
Approximately 40% of the population (all skin categories and phototypes) complain of sensitive skin. Sensitive skin is healthy but overresponsive, meaning it reacts faster and more intensely to several parameters including environmental factors such as temperature changes and the sun, use of cosmetic products, and certain medicines. It experiences discomfort, tingling, burning and intolerance to certain types of products, a condition referred to as neurosensitivity characterized by a lower threshold of tolerance. Currently, all of the causes are not known but an increase in the permeability of the stratum corneum and an exaggeration of the nerve response are considered to be involved in the phenomenon of sensitive skin. Lifestyle factors including tobacco, alcohol, stress, fatigue and emotions also have an effect. A new synthetic tetrapeptide, N -acetyl- L -tyrosyl- L -prolyl- L -phenylalanyl- L -phenylalaninamide (Ac-YPFF-NH2), mimicking a natural opioid peptide was developed with the aim to decrease skin nerve ending stimulation. This tetrapeptide was demonstrated in vitro to reduce cutaneous overreactivity by decreasing release of calcitonin gene-related peptide from sensory neurons via an agonist effect on the μ opioid receptors and in vivo to improve the comfort of sensitive skin by decreasing unpleasant sensations and pain induced by heat and capsaicin. This tetrapeptide targeting an exaggerated nerve response helps to relieve sensitive skin by normalizing the tolerance threshold for environmental factors or certain topically applied uncomfortable products or skincare treatments.
Keywords:  Calcitonin gene-related peptide, μ opioid receptor, nerve endings, peptide, sensitive skin     

Melting heat transfer analysis of electrically conducting nanofluid flow over an exponentially shrinking/stretching porous sheet with radiative heat flux under a magnetic field

Modern magnetic nanomaterial processing operations are progressing rapidly and require increasingly sophisticated mathematical models for their optimization. Stimulated by such developments, in this paper, a theoretical and computational study of a steady magnetohydrodynamic nanofluid over an exponentially stretching/shrinking permeable sheet with melting (phase change) and radiative heat transfer is presented. Besides, wall transpiration, that is, suction and blowing (injection), is included. This study deploys Buongiorno's nanofluid model, which simulates the effects of the Brownian motion and thermophoresis. The transport equations and boundary conditions are normalized via similarity transformations and appropriate variables, and the similarity solutions are shown to depend on the transpiration parameter. The emerging dimensionless nonlinear coupled ordinary differential boundary value problem is solved numerically with the Newton-Fehlberg iteration technique. Validation with special cases from the literature is included. The increase in the magnetic field, that is, the Hartmann number, is observed to elevate nanoparticle concentration and temperature, whereas it dampens the velocity. Higher values of the melting parameter consistently decelerate the boundary layer flow and suppress temperature and nanoparticle concentration. A higher radiative parameter strongly increases temperature (and thermal boundary layer thickness) and weakly accelerates the flow. The increase in the Brownian motion reduces nanoparticle concentrations, whereas a greater thermophoretic body force strongly enhances them. The Nusselt number and Sherwood number are observed to be decreased with an increasing Hartmann number, whereas they are elevated with a stronger wall suction and melting parameter.     

Histopathological and biochemical effects of cyanobacterial cells containing microcystin‐LR on Tilapia fish

Blooms of Microcystis aeruginosa, commonly observed in many lakes of Tamil Nadu, produce the cyanobacterial toxin Microcystin, which has tumor promoting property in fish. Strains of Microcystis aeruginosa species have the same morphology but may vary in their toxicity. In the present study, Microcystin produced by Microcystis aeruginosa from Thenneri lake in Kancheepuram district of Tamil Nadu, was isolated and characterized by high‐performance liquid chromatography and electron spray ionization mass spectroscopy. Based on spectroscopic results the toxin was identified as Microcystin‐LR. Toxicogenicity was evident from the alteration in the activity of antioxidant enzymes [Glutathione S‐transferase and Catalase] and increase of protein and lipid peroxidation contents in Oreochromis niloticus, a fresh water fish species, after controlled exposure to Microcystis aeruginosa cells. Toxicity was further confirmed by histopathological changes in gill, liver and intestine of exposed fish.     

Low sidelobe pattern using Woo filter concepts

This paper presents a new pulse compression technique that can reduce sidelobes significantly. The code used in this is p4, which belongs to the class of polyphase codes. This retains the merit of strong resistance to the Doppler shift effect. This processing technique, which is proposed in this paper, is useful to reduce peak sidelobe level (PSL) and integrated sidelobe level (ISL) but increases the mainlobe width. The results are compared with the Woo filter.     

The interaction of nitrogen molecules with (4, 0) single-walled carbon nanotube: electronic and structural effects

The electronic structure and energetics of (4, 0) single-walled carbon nanotubes (CNTs) interacting with nitrogen have been studied using density-functional calculations. We show that the nanotubes become covered with a stable sheath of N(2) molecules. We have constructed potential energy curves which can be used for the thermodynamic analysis of N(2) adsorption and desorption processes. Our results show that any analysis of the observed properties (for example thermodynamics, stability, and photoluminescence) of air-exposed CNTs needs to consider the N(2) adsorbed on the CNTs.     

Fair Adaptive Cross-Layer Resource Allocation Scheme for IEEE 802.16 Broadband Wireless Networks

In a WiMAX network, the Medium Access Control (MAC) protocol deals with resource allocation to different types of traffic. The key components that ensure Quality of Service (QoS) guarantees in a WiMAX network include Call Admission Control (CAC), Bandwidth and Burst allocation. In this Paper, a Cross-layer framework is designed to efficiently allocate resources to various classes of traffic. CAC and Bandwidth allocation are dealt in the MAC layer, while Burst allocation in the PHYsical layer. The predominant goal of this work is to reduce delay and Information Element (IE) overheads by efficiently utilizing the available frame space. The History based CAC (HCAC) proposed in this paper deals with call acceptance based on the Contention Window (CW) values. The History based Bandwidth Allocation (HBA) scheme deals with allocating bandwidth based on Consumption and Equity measures. The proposed tightly coupled Delay Tolerance based Scheduler (DTS) and Bucket based Burst Allocator (BBA) allocate resources by prioritizing flows with least delay tolerance. It is seen that the proposed schemes offer better performance in contrast to the existing benchmarked schemes in terms of Throughput, Average Delay and Packet Loss Ratio (PLR).

     

Aluminum hydride coated single-walled carbon nanotube as a hydrogen storage medium

We report a first principle study on the hydrogen storage in Aluminum hydride (AlH₃) coated (5, 5) single-walled carbon nanotube (SWCNT). Our study indicates that a SWCNT coated with Aluminum hydride (Alane – AlH₃) can bind up to four hydrogen molecules. At half coverage of AlH₃, the hydrogen storage capacity of the SWCNT is 8.3 wt%. The system with full coverage is also studied and it is found that, even though the hydrogen storage capacity increases, the binding of H₂ is weak. All the H₂ adsorption is molecular with H–H bond length of 0.756 Å. Our result on a full molecular adsorption of hydrogen via light metal hydride is new and it leads to a practically viable storage process.     

Skin moisturization by hydrogenated polyisobutene—Quantitative and visual evaluation

Hydrogenated polyisobutene (HP) is used in topically applied cosmetic/personal care formulations as an emollient that leaves a pleasing skin feel when applied, and rubbed in after application. This effect, although distinguishable to the user, is difficult to define and quantify. Recognizing that some of the physical properties of HP such as film formation and wear resistance may contribute, in certain mechanisms, to skin moisturization, we designed a short-term pilot study to follow changes in skin moisturization. HP's incorporation into an o/w emulsion at 8% yielded increased viscosity and reduced emulsion droplet size as compared to the emollient ester CCT (capric/caprylic triglyceride) or a control formulation. Quantitative data indicate that application of the o/w emulsion formulation containing either HP or CCT significantly elevated skin moisture content and thus reduced transepidermal water loss (TEWL) by a maximal ∼33% against the control formulation within 3 h and maintained this up to 6 h. Visual observation of skin treated with the HP-containing formulation showed fine texture and clear contrast as compared to the control or the CCT formulation, confirming this effect. As a result of increased hydration, skin conductivity, as measured in terms of corneometer values, was also elevated significantly by about tenfold as early as 20 min after HP or CCT application and was maintained throughout the test period. Throughout the test period the HP formulation was 5–10% more effective than the CCT formulation both in reduction of TEWL as well as in increased skin conductivity. Thus, compared to the emollient ester (CCT), HP showed a unique capability for long-lasting effect in retaining moisture and improving skin texture.     

Sunlight/ZnO-mediated photocatalytic degradation of reactive red 22 using thin film flat bed flow photoreactor

Photocatalytic degradation of one of the most widely used cotton dyes, namely reactive red 22 (RR 22), was investigated in the presence of a thin film of ZnO photocatalyst using a thin film flat bed flow photoreactor under solar radiation. The effects of reaction parameters such as pH, amount of ZnO coating, flow rate and concentration of the dye solution on the percentage removal of dye were examined. In a single pass mode at 30 ml/min flow rate, 52.7% decrease in concentration was achieved for 200μM dye solution (pH 10). It has been demonstrated that in continuous circulation mode the time required to decompose half the concentration of the dye in 500 ml of 200 μM was 15.8 min. Complete removal of 200 μM dye solution (pH 10) was achieved at about 100 min.