Tail Model Research Articles

Modeling of Timing Jitter for Single Photon Avalanche Diodes

Timing jitter is an important indication reflecting on the performance of single photon avalanche diodes (SPADs). In this paper, an analytical model is established to predict the temporal response characteristic of SPADs based on the physical progress of photon absorbing and avalanche triggering. The diffusion and drift of carriers in the neutral layer are considered by solving the continuity equation for exponential tail modeling. A Gaussian distribution is used to model the peak response corresponding to photon absorption in avalanche region. The model key physic parameters such as electric field and avalanche triggering probability come from TCAD simulation, which improves the model accuracy. This analytical model is useful to predict the temporal response for given SPAD device structure.

A cross-sectional study of experienced coercion in adolescent mental health inpatients

BackgroundInvoluntary care and coercive measures are frequently present in mental healthcare for adolescents. The purpose of this study was to examine to what extent adolescents perceive or experience coercion during inpatient mental health care, and to examine predictors of experienced coercion.MethodsA cross-sectional sample of 96 adolescent inpatients from 10 Norwegian acute and combined (acute and sub-acute) psychiatric wards reported their experienced coercion on Coercion Ladder and the Experienced Coercion Scale in questionnaires. Staff reported use of formal coercion, diagnoses, and psychosocial functioning. We used two tailed t-tests and mixed effects models to analyze the impact from demographics, alliance with parents, use of formal coercion, diagnostic condition, and global psychosocial functioning.ResultsHigh experienced coercion was reported by a third of all patients. In a mixed effects model, being under formal coercion (involuntary admission and / or coercive measures); a worse relationship between patient and parent; and lower psychosocial functioning, significantly predicted higher experienced coercion. Twenty-eight percent of the total sample of patients reported a lack of confidence and trust both in parents and staff.ConclusionsRoughly one third of patients in the sample reported high experienced coercion. Being under formal coercion was the strongest predictor. The average scores of experienced coercion in subgroups are comparable with adult scores in similar care situations. There was one exception: Adolescents with psychosis reported low experienced coercion and almost all of them were under voluntary care.

Antipsoriatic effect of fatty acid enriched fraction of Vernonia anthelmintica Willd. fruits

Ethnopharmacological relevanceVernonia anthelmintica has been utilized conventionally as an ingredient in Ayurveda and traditional Uighur medicine for management of various skin ailments, and scientific data's have substantiated its use in treating vitiligo, dermatosis and leucoderma. The present investigation was focused to evaluate the antipsoriatic activity of V. anthelmintica fruit extracts and fractions. Materials and methodsOintment containing dichloromethane (DCM) and methanol (MeOH) extracts at topical dose of 2.5% and 5% (w/w) was evaluated using mouse tail model of psoriasis. Bioactivity-guided fractionation (F1-F7) of most active extract was carried out and fractions were again subjected to mouse tail model. Further the activity of bioactive fraction was confirmed in HaCaT (human keratinocyte) cell line using MTT (3-(4,5-dimethylthiazol-2-yl)− 2,5-diphenyltetrazolium bromide) assay and its chemical characterization was done via gas chromatography mass spectrometry (GC-MS). ResultsThe dichloromethane extract (5%, w/w) showed statistically significant (* p < 0.05) antipsoriatic activity (66.97 ± 2.68%) with respect to control (25.45 ± 1.80%) and equivalent to that of the standard drug, retino-A 0.05%, (72.47 ± 2.14%) in terms of degree of orthokeratosis, whereas methanol extract (5%, w/w) showed significant (* p < 0.05) differentiation (45.86 ± 2.02%) in comparison to the control group. Out of all fractions, F6 showed statistically significant (* p < 0.05) antipsoriatic activity (69.27 ± 2.76%) with respect to control and equivalent to that of the standard. F6 (15.6–1000 µg/ml) showed dose-dependent inhibition of HaCaT cell lines proliferation which suggests keratinocyte modulating activity of V. anthelmintica. Chemical characterization of F6 revealed that essential fatty acids (i.e., linoleic acid, palmitic acid, oleic acid and stearic acid) formed the bulk of bioactive fraction. ConclusionAmeliorative effect of V. anthelmintica in psoriasis might be attributed to the presence of essential fatty acids and thus corroborates its traditional use in the treatment of skin ailments.

Vertical tail FEA with a CAD/CAE based multidisciplinary process

PurposeThe purpose of this paper is to make an analytical comparison of two vertical tail models from a structural point of view.Design/methodology/approachThe original vertical tail design of PZL-106BT aircraft was used for Computer aided design (CAD) modeling and for creating the finite element model.FindingsThe nodal displacements, Von-Mises stresses and Buckling factors for two vertical tail models have been found using the finite element method. The idea of a possible Multidisciplinary concept assessment and design (MDCAD) concept was presented.Practical implicationsThe used software analogy introduces an idea of having an automated calculation procedure within the framework of MDCAD.Originality/valueThe aircraft used for calculation had undergone a modification in its vertical tail length, as there was an urgent need to calculate for the plane’s manufacturer, PZL Warszawa – Okecie.

Effect of Static Compression Loads on Intervertebral Disc: An in Vivo Bent Rat Tail Model.

To evaluate how well different magnitudes of compression-induced degenerative changes using a bent rat tail model simulated human lumbar lordosis. It has been shown that compression plays an important role in intervertebral disc degeneration (IDD). Sprague-Dawley rats (n = 25) were instrumented with a special compressive apparatus that was used to bend the intervertebral disc between the 8th and the 10th caudal vertebral bodies using two Kirschner wires inserted percutaneously into the middle of two tail vertebrae. Then, rats were divided into five different static compression loads (control, sham, 1.8 N, 4.5 N, and 7.2 N). The degeneration of the discs was evaluated by magnetic resonance imaging (MRI), histology, gene expression of anabolism and catabolism after 2 weeks. We used the signal characteristics of the disc in T2-weighted MRI to reflect the changes caused by degeneration as this is the most relevant and clinically recognized way to assess IDD. Pfirrmann classification was used to classify disc images. The tail discs from C8-9 and C9-10 with their two adjacent half vertebrae were carefully cut out and decalcified. Then the sections were paraffin-embedded and cut into 5-μm sections by histotome. Finally, they were stained with Safranin O-Fast Green and hematoxylin, and hematoxylin and eosin, respectively. Images were taken using a microscope and staining and compression-induced changes were assessed by a Masuda's grading scale. The relative expression levels of mRNA encoding rat anabolic genes and catabolic genes were evaluated by real-time reverse transcription (RT)-polymerase chain reaction (PCR). The mRNA expression fold change of the target gene was calculated using the 2-ΔΔCt method in the loaded and unloaded disc. As the loading magnitude increased, static compression produced a significantly progressive decrease in nucleus intensity on T2-weighted MRI, a decrease of aggrecan and Type II collagen, an increase in Matrix metallopeptidase-3 (MMP-3) and MMP-13 expressions, and a histomorphological degeneration. The sham group had a score of 1.4 ± 0.3, the 1.8 N group had a score of 2.4 ± 0.3, the 4.5 N group had a score of 3.2 ± 0.3, and the 7.2 N group had a score of 4.4 ± 0.3, which was based on the Pfirrmann classification score, in which the control group had a score of 1. These results demonstrated that the sham group was not significantly different from the control group. Histological analysis showed that in the loaded disc, the size of the nucleus was reduced and that the annular layer was disorganized. Based on the Masuda grading scale, scores were as follows: for the control group, 3.8 ± 0.35; sham, 4.2 ± 0.35; 1.8 N, 5.4 ± 0.35; 4.5 N, 7.6 ± 0.35; and 7.2 N, 10 ± 0.35. The gene expression was divided into the following: anabolic genes (aggrecan, collagen type1-α1, and collagen type2-α1) and catabolic genes (MMP-3 and MMP-13). Aggrecan and collagen type 2 were, respectively, downregulated from 0.42 ± 0.04 to 0.21 ± 0.04 and from 0.93 ± 0.06 to 0.17 ± 0.06 as the magnitude of compression increased, whereas collagen type 1 was significantly upregulated, from 2.49 ± 0.19 to 4.40 ± 0.19, when compared with the control group (from 1.8 to 7.2 N, P < 0.05). Catabolic genes MMP-3 and MMP-13 were significantly upregulated in all experimental groups (P < 0.05, MMP-3: from 1.46 ± 0.18 to 3.44 ± 0.18; MMP-13: from 1.19 ± 0.12 to 2.82 ± 0.13); however, MMP-13 exhibited no significant changes but tended to be upregulated when compared with the 1.8 N group with the 4.5 N group. Different stresses led to different processes of degenerative changes, the concave disc degenerating more severely as stress gradually increased.

Honokiol alleviates the degeneration of intervertebral disc via suppressing the activation of TXNIP-NLRP3 inflammasome signal pathway.

Intervertebral disc degeneration (IVDD) is a multifactorial disease and responsible for many spine related disorders, causes disability in the workforce and heavy social costs all over the world. Honokiol, a low molecular weight natural product, could penetrate into and distribute in IVDs to achieve therapeutic effect in a rat tail model. Therefore, the present study was undertaken to examine the antiinflammatory, antioxidation and IVD-protective effect of honokiol using nucleus pulposus cells and investigate its mechanisms to provide a new basis for future clinical treatment of IVDD. In the current study, we demonstrated that honokiol inhibits the H2O2-induced apoptosis (caspase-9, caspase-3, and bax), levels of oxidative stress mediators (ROS, MDA), expression of inflammatory mediators (Interleukin-6, COX-2, and iNOS), major matrix degrading proteases (MMP-3, MMP-13, ADAMTS5, and ADAMTS4) associated with nucleus pulposus degradation. Furthermore, we found nucleus pulposus protective ability of honokiol by up-regulating extra cellular matrix anabolic factors like type II collagen (Col II) and SOX9 in nucleus pulposus. We also found that honokiol suppressed the phosphorylation of NF-kB and JNK, and activation of TXNIP-NLRP3 inflammasome in H2O2-stimulated nucleus pulposus cells, thereby inhibiting the activation of downstream inflammatory mediators such as Interleukin-1β. Furthermore, honokiol showed a cartilage protective effect in the progression of IVDD in a rat model induced by puncture. Thus, our results demonstrate that honokiol inhibited the H2O2 induced apoptosis, oxidative stress, and inflammatory responses through the depression of TXNIP/NLRP3/caspase-1/ Interleukin - 1β signaling axis and the activation of NF-kB and JNK. Honokiol possess nucleus pulposus protective properties and may be of value in suppressing the pathogenesis of IVDD.

Can People Learn about ‘Black Swans’? Experimental Evidence

How do people cope with tail risk? In a lab experiment that removed informational and incentive confounds, subjects overwhelmingly behaved like Bayesian learners. The results of simulations further revealed that if one is to survive under tail risk, one needs to follow the Bayesian approach, as all boundedly rational alternatives fail. These findings support the Bayesian assumption commonly made in prior studies on tail risk and model uncertainty, and they also demonstrate the importance of optimal learning under tail risk. Received February 15, 2017; editorial decision December 24, 2017 by Editor Andrew Karolyi. Authors have furnished supplementary data and code, which are available on the Oxford University Press Web site next to the link to the final published paper online.

Effect of postharvest UV-C treatment on the microbial quality of ‘Şalak’ apricot

Abstract Inactivation of natural flora found on cv. ‘Salak’ apricot surfaces was investigated using a newly designed UV-C treatment system equipped with four UV lamps and a rotating roller bearing. Multiple Point Source Summation (MPSS) Model was used to estimate UV light intensity field in this processing chamber. Although MPSS model over-predicted the UV intensity data, light intensity profile showed a good agreement with the radiometric measurements. UV-C treatment of apricots resulted in 3-log reduction in the number of total mesophilic aerobic bacteria (TAPC) at 32.3 W m−2 of average UV light intensity for 16 min at 31.01 kJ m−2 of UV dose whereas 2.38-log reduction was achieved for yeast and mould count (YMC) after 4 min of UV exposure at 7.75 kJ m−2 of UV dose. On the other hand, complete inactivation of coliform bacteria was observed after all treatments. Statistical analysis indicated that further extension of the exposure time did not cause any significant effect on the inactivation of natural flora of apricot surfaces. Additionally, the inactivation data obtained for TAPC and YMC were modelled by using log-linear regression, Biphasic model, log-linear + tail, Weibull model, Weibull + tail, double Weibull and biphasic + shoulder models. The inactivation kinetics of TAPC and YMC were best described by log linear + tail model with the smallest root mean squared error (RMSE) and the highest regression coefficient (R2 > 0.90). These results suggest that UV-C treatment can be applied to control the natural flora on cv. ‘Salak’ apricots. Use of a rotating roller bearing is highly appreciated in UV-C systems to provide equal radiation among fruit surfaces.

Pivotal role of Acitretin nanovesicular gel for effective treatment of psoriasis: ex vivo-in vivo evaluation study.

The goal of the current study was to explore the potential benefits of Acitretin (Act) nanovesicular gel as a prospective antipsoriatic topical delivery system counteracting the drug challenges in terms of its extremely low aqueous solubility, instability, skin irritation, and serious systemic adverse effects. Act-loaded niosomes were successfully developed, entirely characterized, and optimized. Further evaluation of the optimized formula was conducted regarding its stability and ex vivo cytotoxicity on different cell lines. The optimized niosomal vesicles were then incorporated in gel base matrix and investigated by sequential ex vivo (skin permeation and deposition) and in vivo (skin irritation and antipsoriatic activity using mouse tail model) experiments. The optimized Act-loaded niosomes (span 60:cholesterol molar ratio 1:1) were spherical in shape and exhibited the highest entrapment efficiency (90.32±3.80%) with appropriate nanosize and zeta potential of 369.73±45.45 nm and −36.33±1.80 mV, respectively. Encapsulation of the drug in the nanovesicles was further emphasized by differential scanning calorimetric and powder X-ray diffraction studies. After 3 months storage at 4±1°C, the optimized formula preserved its stability. Act nano niosomal gel produced a remarkable enhanced ex vivo permeation profile up to 30 h and significant drug deposition in the viable epidermal–dermal layers compared with those of Act gel. The pronounced antipsoriatic activity of the medicated nano niosomes was proved ex vivo in HaCaT cells (a keratinocyte cell line). Topical application of Act nano niosomal gel to mouse tail model further established its distinct in vivo antipsoriatic superiority in terms of significantly higher orthokeratosis, drug activity, and reduction in epidermal thickness compared with the control and other gel formulations. Also, negligible skin irritation and better skin tolerability of Act nanovesicular gel were revealed by primary irritation index and histopathologic examination.

The open long tail model between new culture and digital technology

Purpose of the paper : The aim of this paper is to describe an emerging business model that comes from the digitization of the world of tangible products. Methodology : The creation of niche products, their production and sales in an open business model is analyzed through the literature review of bth models and sustained by the analysis of practice cases. Findings : This new business model, defined by the authors as the open long tail model, includes the features of both the open business model and the long tail model because it sustains the collaborative trend of the web generation and creates a large number of niche, physical things rather that “just pixels on screens”. Research limits : Given its focus on the empirical evidence from the diffusion of new digital and flexible technologies, our analysis has identified a new trend in the manufacturing industry business model that seems to have a positive effect on the organization as well as the customer. Practical implications : The future of this emerging business model looks promising thanks to its democratization of creativity and manufacturing trajectory and its capability to create more revenue for anyone willing to undertake this venture. Originality of the paper : This new stream of creativity, democratization and innovation is possible thanks to the open long tail model based on the new user that wants to make objects, the emergence of digital tools for design and production, the collaboration between actors.

A Multiagent-Based Approach for Vehicle Routing by Considering Both Arriving on Time and Total Travel Time

Arriving on time and total travel time are two important properties for vehicle routing. Existing route guidance approaches always consider them independently, because they may conflict with each other. In this article, we develop a semi-decentralized multiagent-based vehicle routing approach where vehicle agents follow the local route guidance by infrastructure agents at each intersection, and infrastructure agents perform the route guidance by solving a route assignment problem. It integrates the two properties by expressing them as two objective terms of the route assignment problem. Regarding arriving on time, it is formulated based on the probability tail model, which aims to maximize the probability of reaching destination before deadline. Regarding total travel time, it is formulated as a weighted quadratic term, which aims to minimize the expected travel time from the current location to the destination based on the potential route assignment. The weight for total travel time is designed to be comparatively large if the deadline is loose. Additionally, we improve the proposed approach in two aspects, including travel time prediction and computational efficiency. Experimental results on real road networks justify its ability to increase the average probability of arriving on time, reduce total travel time, and enhance the overall routing performance.

Fishnet model for failure probability tail of nacre-like imbricated lamellar materials

Nacre, the iridescent material of the shells of pearl oysters and abalone, consists mostly of aragonite (a form of CaCO3), a brittle constituent of relatively low strength ([Formula: see text]10 MPa). Yet it has astonishing mean tensile strength ([Formula: see text]150 MPa) and fracture energy ([Formula: see text]350 to 1,240 J/m2). The reasons have recently become well understood: (i) the nanoscale thickness ([Formula: see text]300 nm) of nacre's building blocks, the aragonite lamellae (or platelets), and (ii) the imbricated, or staggered, arrangement of these lamellea, bound by biopolymer layers only [Formula: see text]25 nm thick, occupying [Formula: see text] of volume. These properties inspire manmade biomimetic materials. For engineering applications, however, the failure probability of [Formula: see text] is generally required. To guarantee it, the type of probability density function (pdf) of strength, including its tail, must be determined. This objective, not pursued previously, is hardly achievable by experiments alone, since [Formula: see text] tests of specimens would be needed. Here we outline a statistical model of strength that resembles a fishnet pulled diagonally, captures the tail of pdf of strength and, importantly, allows analytical safety assessments of nacreous materials. The analysis shows that, in terms of safety, the imbricated lamellar structure provides a major additional advantage-∼10% strength increase at tail failure probability [Formula: see text] and a 1 to 2 orders of magnitude tail probability decrease at fixed stress. Another advantage is that a high scatter of microstructure properties diminishes the strength difference between the mean and the probability tail, compared with the weakest link model. These advantages of nacre-like materials are here justified analytically and supported by millions of Monte Carlo simulations.

Reliability Estimation Using Markov Chain Monte Carlo–Based Tail Modeling

Tail modeling is an efficient method used in reliability estimation of highly safe structures. Classical tail modeling is based on performing limit-state function evaluations through a sampling scheme, selecting a threshold value to specify the tail part of the cumulative distribution function, fitting a proper model to the tail part, and estimating the reliability. In this approach, limit-state function calculations that do not belong to the tail part are mostly discarded, and so majority of limit-state evaluations are wasted. In this paper, Markov chain Monte Carlo method with Metropolis–Hastings algorithm is used to draw samples from the tail part only so that a more accurate reliability index prediction is achieved. A commonly used proposal distribution formula is modified by using a scale parameter. The optimal value of this scale parameter is obtained for various numerical example problems with a varying number of random variables, and an approximate relationship is obtained between the optimal value of the scale parameter and the number of random variables. The approximate relationship is tested on the reliability prediction of a horizontal axis wind turbine and observed to work well. It is also found that the proposed approach is more accurate than the classical tail modeling when the number of variables is less than or equal to four. For a larger number of random variables, none of the two approaches are found to be superior to another.

MicroRNA-132 upregulation promotes matrix degradation in intervertebral disc degeneration

MicroRNAs (miRNAs) have been shown to be involved in the pathogenesis of intervertebral disc degeneration (IDD). This experiment was designed to study the expression and role of the miRNA, miR-132, in IDD. MiR-132 expression in human nucleus pulposus (NP) tissue was assessed by quantitative real-time PCR. The methylation status of the miR-132 was assessed with methylation-specific PCR and bisulfite sequencing PCR. The regulation of growth differentiation factor5 (GDF5) expression by miR-132 was evaluated by luciferase reporter assay. Moreover, we investigated the function of miR-132 on IDD in vivo using a classic needle-punctured rat tail model. These results showed that miR-132 expression was upregulated during IDD and this upregulation was associated with hypomethylation of its promoter. MiR-132 overexpression led to increased expression of ECM catabolic factors, including MMP13 and ADAMTS4, in NP cells while levels of anabolic proteins, such as type II collagen and aggrecan, were diminished. GDF5 was identified as a direct target of negative regulation by miR-132. MAPK/ERK signaling was also found to be associated with miR-132-induced ECM degradation. In addition, we showed that miR-132 inhibition effectively attenuated NP ECM degradation in IDD in vivo. Our findings demonstrated that miR-132 promotes ECM degradation by human NP cells by direct targeting of GDF5. Hence, miR-132 represents a potential therapeutic target in the treatment of IDD.

English

The mouse tail model was used to measure and compare antipsoriatic activity of Acalypha wilkesiana and Culcasia scandens with that of earlier reported Kigelia africana stem methanol extract by the same authors, with the objective of finding out which of these plant extracts can be a better drug option for the treatment of psoriasis. The results obtained showed that topically administered extracts (50-200 mg/ml) induced a significant and dose-dependent increase in %orthokeratosis in the epidermis of the mice tails. % orthokeratosis values were 35.5-43.4 (A. wikesiana), 29.7-47.4 (K. africana), 31.9-36.5 (C. scandens) for the methanol ointments; 29.3-36.2 (A. wikesiana), 32.3-58.2 (K. africana), 29.40-56.2 (C. scandens) for the hexane extracts. In general, the methanol extracts produced higher % othokeratosis. No deterioration in the general condition of the mice in any group was observed. However, erythema was observed on the tails of the mice on which the K. africana stem methanol extract ointment (200 mg/ml) was applied. No tail erythema was observed in any other group. Application of the ointments resulted in the softening of the tails. In general, the irritation potentials of the ointments were relatively low when compared to that induced by dithranol a drug commonly used in the treatment of psoriasis. Only the A. wilkesiana methanol extract ointment (200 mg/ml) showed greater than 40% drug activity. Thus, A. wilkesiana appears to be the better plant for use in possible drug development for the management and cure of psoriasis because A. wilkesiana ointment showed more prospects of being an antipsoriatic topical agent when compared to C. scandens or K. africana, as the drug activity of the methanol extract of this plant was greater than 40% and quite similar to that of K. africana without the corresponding irritation potential or erythema. Key words: Psoriasis, mouse-tail model, Acalypha wilkesiana, Culcasia scandens, Kigelia africana, dithranol drug activity, irritation potential.

The dust environment of comet 67P/Churyumov–Gerasimenko: results from Monte Carlo dust tail modelling applied to a large ground-based observation data set

We present an extensive data set of ground-based observations and models of the dust environment of comet 67P/Churyumov–Gerasimenko covering a large portion of the orbital arc from about 4.5 au pre-perihelion through 3.0 au post-perihelion, acquired during the current orbit. In addition, we have also applied the model to a dust trail image acquired during this orbit, as well as to dust trail observations obtained during previous orbits, in both the visible and the infrared. The results of the Monte Carlo modelling of the dust tail and trail data are generally consistent with the in situ results reported so far by the Rosetta instruments Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS) and Grain Impact Analyser and Dust Accumulator (GIADA). We found the comet nucleus already active at 4.5 au pre-perihelion, with a dust production rate increasing up to ∼3000 kg s−1 some 20 d after perihelion passage. The dust size distribution at sizes smaller than r = 1 mm is linked to the nucleus seasons, being described by a power law of index −3.0 during the comet nucleus southern hemisphere winter but becoming considerably steeper, with values between −3.6 and −4.3, during the nucleus southern hemisphere summer, which includes perihelion passage (from about 1.7 au inbound to 2.4 au outbound). This agrees with the increase of the steepness of the dust size distribution found from GIADA measurements at perihelion showing a power index of −3.7. The size distribution at sizes larger than 1 mm for the current orbit is set to a power law of index −3.6, which is near the average value of in situ measurements by OSIRIS on large particles. However, in order to fit the trail data acquired during past orbits previous to the 2009 perihelion passage, a steeper power-law index of −4.1 has been set at those dates, in agreement with previous trail modelling. The particle sizes are set at a minimum of r = 10 μm, and a maximum size, which increases with decreasing heliocentric distance, in the 1–40 cm radius domain. The particle terminal velocities are found to be consistent with the in situ measurements as derived from the instrument GIADA on board Rosetta.

Understanding Operational Risk Capital Approximations: First and Second Orders

We set the context for capital approximation within the framework of the Basel II/III regulatory capital accords. This is particularly topical as the Basel III accord is shortly due to take effect. In this regard, we provide a summary of the role of capital adequacy in the new accord, highlighting along the way the significant loss events that have been attributed to the Operational Risk class that was introduced in the Basel II and III accords. Then we provide a semi-tutorial discussion on the modelling aspects of capital estimation under a Loss Distributional Approach (LDA). Our emphasis is to focus on the important loss processes with regard to those that contribute most to capital, the so called high consequence, low loss processes. This leads us to provide a tutorial overview of heavy tailed loss process modelling in OpRisk under Basel III, with discussion on the implications of such tail assumptions for the severity model in an LDA structure. This provides practitioners with a clear understanding of the features that they may wish to consider when developing OpRisk severity models in practice. From this discussion on heavy tailed severity models, we then develop an understanding of the impact such models have on the right tail asymptotic of the compound loss process and we provide detailed presentation of what are known as first and second order tail approximations for the resulting heavy tailed loss process. From this we develop a tutorial on three key families of risk measures and their equivalent second order asymptotic approximations: Value-at-Risk (Basel III industry standard); Expected Shortfall (ES) and the Spectral Risk Measure. These then form the capital approximations. We then provide a few example case studies to illustrate the accuracy of these asymptotic capital approximations, the rate of the convergence of the asymptotic result as a function of the LDA frequency and severity model parameters, the sensitivity of the capital approximation to the model parameters and the sensitivity to model mis-specification.

Quantitative Evaluation of the Antipsoriatic Activity of Flavonoids from Cassia tora Linn. Leaves

The plant Cassia tora L. (Caesalpiniaceae) is traditionally claimed to be useful in the treatment of psoriasis and other skin diseases. In the previous work, three flavonoids viz quercetin-3-O-β-d-glucuronide (I), luteolin-7-O-β-glucopyranoside (II) and formononetin-7-O-β-D-glucoside (III) were isolated from Cassia tora leaves. As an extension of work, the present study aimed to evaluate antipsoriatic activity of these flavonoids using in vitro and in vivo model. In vitro antiproliferant assay of the ethanol extract and isolated flavonoids was done on HaCaT cell lines. Mouse tail test was used for the evaluation of antipsoriatic activity of ethanol extract (100, 200 and 400 mg/kg b.w.) and bioactive flavonoids (50 mg/kg b.w.) in Swiss albino mice. Maximum antiproliferant activity was shown by isolated flavonoids II and III (58.65 and 87.74 μg/ml) in HaCaT cell inhibition assay. In mouse tail model, a significant reduction in epidermal thickness and significant orthokeratosis with respect to control was observed in groups treated with ethanol extract (200 and 400 mg/kg) and isolated flavonoids II, III. From the above data, the flavonoid II (luteolin-7-O-β-glucopyranoside) showed maximum antiproliferant activity and significant orthokeratosis. This study suggests the potential antipsoriatic activity of the flavonoids of Cassia tora and a need for studies to understand the mechanism of action.

Corona Discharge Plasma Jet Inactivates Food-borne Pathogens Adsorbed onto Packaging Material Surfaces

The potentiality of corona discharge plasma jet (CDPJ) for disinfection of food packaging materials, including glass, polyethylene, polypropylene, nylon and paper foil, was evaluated. CDPJ was generated using a high voltage (20 kV) pulsed DC power source, at 1.5 A current and 58 kHz frequency. The separation distance between plasma electrode and sample plate during the treatment was 25 mm. Upon treating food pathogens-loaded packaging materials by the plasma, 4.5–5.0 log/cm2 reductions (99.999%) in viable cell counts of Escherichia coli O157:H7 and Staphylococcus aureus were observed in 120 s. Another tested pathogen Salmonella Typhimurium was inactivated by 3.0 log/cm2 units. The patterns of inactivation of pathogens are fitted well to Weibull tail model. Compared to untreated controls, the CDPJ-treated packaging materials exhibited insignificant (p > 0.05) changes in the optical characteristics, tensile strengths, surface temperatures and strain-induced deformation. Therefore, the most common food packaging materials harboring bacterial pathogens could be disinfected by the CDPJ without compromising physicomechanical properties of materials. Copyright © 2017 John Wiley & Sons, Ltd.

Performance evaluation of non-ionic surfactant based tazarotene encapsulated proniosomal gel for the treatment of psoriasis

The study aims to explore the potential of non-ionic surfactant based proniosomal gel (PNG) in improving the topical delivery of tazarotene by in vitro and in vivo studies. The PNG was prepared using coacervation phase separation method composed of span, stearylamine, cholesterol, and lecithin. The PNG demonstrated favorable vesicle size (3.26±0.22μm) and percent encapsulation efficiency (49.50±2.3%). The PNG was evaluated for viscosity which indicated that the ratio of span:cholesterol:stearylamine (64.5:30.5:5mM) demonstrated no any fluctuations in viscosity. The scanning electron micrographs exhibited spherical vesicles with sharp boundaries. The in vitro drug release through cellulose membrane and rat's skin were found to be in the following order of the formulation code A2>A4>A3>A5 and A4>A2>A3>A5, respectively, which showed the prolonged release of entrapped tazarotene. Further, in vitro drug permeation and retention studies revealed that formulations A2 and A4 showed the higher percent of drug permeation whereas formulations A3 and A5 showed the higher percent of drug retention through rat's skin. Moreover, PNG A2 and A4 formulations demonstrated good stability characteristics at different temperature conditions. The stability in the presence of detergent revealed that no any abrupt change in turbidity. The skin irritation studies performed with formulations A2 and A4 showed no erythema compared with the plain PNG. The male Albino NMRI mice tail model was used to performed in vivo skin histological examination which revealed that an increase in the orthokeratosis strengthened. Thus, all the results concluded that surfactant, Span 60 based PNG formulations have shown a good ability to increase drug accumulation in the various skin layers and more potential carrier for topical delivery of tazarotene for an effective therapy of psoriasis.