Mosquito Repellent and Oviposition deterrent activities of Solanum nigrum seed extract against malaria vector Anopheles stephensi

This study was carried out to evaluate mosquito repellent and oviposition deterrent activities of Solanum nigrum against malaria vector Anopheles stephensi. Hexane extract of the seeds of Solanum nigrum was used for repellent and oviposition deterrent activity against mosquito vector Anopheles stephensi Liston (Diptera: Culicidae) in laboratory bio-assays. Percent protection obtained against An. stephensi was 100% in 0 hours and 81% after 6 hours at the 10% concentration of the extract as compared to 100% after 6 hours at 2.5% DEET solution. The concentrations of the hexane extract of the seeds of Solanum nigrum ranging between 0.03125% and 0.5% showed 27 to 99.5% oviposition deterrence in treated bowls as compared to untreated control. These observations show that the Solanum nigrum seed extract is an effective personal protection measure and oviposition deterrent against mosquito vectors. KEYWORD: Solanum nigrum, Repellency, Oviposition deterrent, Anopheles stephensi Introduction Continued use of the synthetic chemical insecticide based intervention measures for vector control has resulted in lower efficacy of the insecticide in controlling the medically important disease vectors. The operational control failure, namely development of insecticide resistance in disease vectors to commonly used synthetic chemical insecticide in public health sprays has made the disease control more difficult The most effective compound of plant origin for the control of mosquitoes is pyrethrum extract obtained from Chrysanthemum cinneraefolium flowers Abstract Online International Interdisciplinary Research Journal, {Bi-Monthly}, ISSN2249-9598, Volume-III, Issue-VI, Nov-Dec2013 w w w . o i i r j . o r g I S S N 2 2 4 9 -9 5 9 8 Page 327 Solanum nigrum and Solanum xanthocarpum, have shown mosquito larvicidal properties (Singh et. al.2001, Singh and Mosquito repellent and oviposition deterrent properties of plants can be exploited for alternate vector control strategy. Mosquito repellents are commonly used for personal protection against mosquito bites and thus help in prevention of the disease transmission. Similarly oviposition deterrents can be used to prevent mosquitoes from egg laying in container breeding habitats. Personal protection against mosquito bites was reported for the genus Eucalyptus maculate citriodon Material and methods Hexane Extract of seeds of Solanum nigrum Ripe fruits were collected from the wild Solanum nigrum plants from villages in Delhi state. Fruits were dried in shade and ground to fine powder in an electric grinder. Hexane extract of seeds was made essentially following the method of (Mehra and Hiradhar). Twenty five gram seed powdered material was extracted three times in a soxhlet apparatus using 750 ml normal hexane at50 0 C. The extract was made solvent free and the final residue of hexane extract of Solanum nigrum obtained, and then kept at −20 0c until testing for adult repellent activity. Mosquito Strains for Repellency and Oviposition deterrence Mosquito species An. stephensi maintained at National Institute of Malaria Research laboratory was used for these studies. Adult mosquitoes were provided with 10% sucrose solution. The 6 days old females starved for 12 hours before the experiment were used for repellent properties and 6 days old blood fed gravid adults were used for oviposition deterrent properties. Preparation of the Repellent and Control Replicates 500ml of 10% sugar solution was prepared in water. Sufficient quantity of bleached cotton was taken to be stacked into a 500 ml Styrofoam glass. 460 ml of above sugar solution was poured in to the glass and the cotton was socked. The cotton at the top was stretched out side in to circular foam. Remaining 40 ml was used to prepare repellent formulation. To 40 ml of the sugar solution required quantity of hexane extract concentrate was mixed to arrive at the desired concentrations, namely, 2.5%, 5%, and 10% and was poured evenly on the sugar soaked cotton in the above Styrofoam glass. Similarly DEET 2.5% in 10% sugar soaked cotton was prepared for use as positive control and only 10% sugar soaked cotton was used as negative controls. For hexane extract of seed of Solanum nigrum, known quantity of residue extract was re-dissolved in hexane to make a 10% (w/v) stock solution. Various test concentrations viz. 2.5%, 5%, and 10% were prepared in distilled water using freshly made stock solution. Controls were supplemented with the equal amount hexane required for the experiment without extracts. Tween-80 was used as an emulsifier at 0.05% concentration in the final test solution. Repellency test These studies were carried out in a room maintained at 27 0 C and 70% RH following the procedure described in Protocols for Uniform Evaluation of Insecticides for use in Vector Control (NIMR 2005). The prepared cages with the mosquitoes were placed in the room. In these cages, the Styrofoam glasses with cotton soaked with three different concentrations of seed hexane extract of Solanum nigrum namely 2.5%, 5%, and 10% sugar solution, DEET 2.5% (positive control) in 10% sugar solution and 10% sugar solution (negative control) were placed in four different corners and one in the centre of the cage. After five-minute landing counts were made at 0, 1, 2, 4, 5, and 6 hours. The cups were removed from the cage after the five minute observation at each interval of time. For subsequent exposure the position of the cups were inter changed to different corners. Landing rates of the mosquitoes on different concentrations of the formulation of hexane extract of seed of Solanum nigrum (2.5, 5, and 10 %), DEET (2.5%) and sugar (10%) were recorded. Data was reported as mean of the observations for each of the formulation. Percent repellency was calculated by using the following formula (Sharma and Ansari 1994) Where Control is the mean number of mosquitoes landing on negative control (10% sugar solution); and Treated is the mean number of mosquitoes landing on the repellents (DEET and seed extract of Solanum nigrum). Oviposition deterrent Mosquitoes were maintained at National Institute of Malaria Research laboratory. Lab reared mosquito species An. stephensi was used for these studies. The experiments were run at room temperature and humidity following the procedure described in Protocols for Uniform Evaluation of Insecticides for use in Vector Control (NIMR 2005). Twenty gravid female An. stephensi were transferred to each mosquito in to experimental cage. Plastic bowls containing 100 ml of water were treaeted with seed extract to obtain test solution 0.5 %, 0.25%, 0.125, 0.0625 and 0.03125%. In these cages, two bowls holding 100 ml of water were places of each case, one treated and the other with a solvent control that contain 1% hexane. Three replicates for each concentration were run with cages places side by side for each bioassay. The experiments run 24 hours and the number of eggs laid in treated and non-treated bowls was recorded. Oviposition deterrence was calculated as follows: Statistical Analysis: A two way ANOVA was performed to test whether there is a significant difference among the different concentration(viz. 2.5%,5%,10% ) of the extract and 2.5% DEET as also among different durations (viz. 0h,1h,2h,4h and 6h). Student t test was performed to find the difference between the mean no of eggs laid in treated and non-treated bowl. Results Results of laboratory testing of the repellent activity of Solanum nigrum extract are shown in table 1 & 2. Table1 show the mean no. of mosquitoes landing at different concentrations of the extract and 2.5 % DEET in six hours. The % repellency of An stephensi is given in table2. It is evident from the data that the overall repellency rates of the hexane extract of Solanum nigrum varied between 80-100% (Table2). The hexane extract of seed showed strong repellent activity against adult Anopheles stephensi (100% in 0 hours and 81% in 6 hours) at the 10% concentration. Against DEET-2.5%, An. stephensi have shown 100% repellency in 6 hours. It was found that the effect of the various concentrations differ significantly (p<0.001). Similarly, the effect of durations differed significantly (p=0.030). Discussion The extract made from Solanum nigrum seeds possessed significant repellent properties against An. stephensi. 10% concentration produced 100% repellency up to six hour which is similar to that reported for currently used synthetic compound DEET, A13-35765, A13-37220 and CIC-4 (Schreck and Mc 1994, Coleman et. al. 1993). The percent repellency of Solanum nigrum extract at different observation periods (0hr, 1hr, 2hr, 4hr and 6hr) ranged from 66.71-100%. From the observed data on the repellency and oviposition deterrence against the important disease vector it can be concluded that the dose of 10% and 0.25% could be used for the achieving the desired level of protection against bites and reduce oviposition of An. stephensi. However, these results pertain to the effectiveness in cage experiments using only sugar solution as attractant. Further isolation and purification could lead to identify more potent compound. In laboratory oviposition deterrent test, the seed extract of Solanum nigrum greatly reduced the number of eggs deposited by gravid An. stephensi. At the highest concentrations the extracts (0.5%) an egg lying was reduced up to 99%. Present studies data showed the repellency and oviposition deterrence against An. stephensi vector of malaria. It can be concluded that dose of 10% and 0.25% could be used for achieving the desired level of protection against landing and reduce egg laying of this mosquito. However, these results pertain to the effectiveness in cage experiments using only sugar solution as attractant. Thus, further confirmation by testing this repellent in lab. A subject to evaluate the repellency effect is needed. Further research is being continued to develop new repellents from a natural origin that not only offer effective anti-mosquito products but are also bio-rational alternatives to synthetic chemicals

Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine

[This corrects the article DOI: 10.1186/s13054-016-1208-6.]

More than smell - COVID-19 is associated with severe impairment of smell, taste, and chemesthesis

Recent anecdotal and scientific reports have provided evidence of a link between COVID-19 and chemosensory impairments, such as anosmia. However, these reports have downplayed or failed to distinguish potential effects on taste, ignored chemesthesis, and generally lacked quantitative measurements. Here, we report the development, implementation, and initial results of a multilingual, international questionnaire to assess self-reported quantity and quality of perception in 3 distinct chemosensory modalities (smell, taste, and chemesthesis) before and during COVID-19. In the first 11 days after questionnaire launch, 4039 participants (2913 women, 1118 men, and 8 others, aged 19-79) reported a COVID-19 diagnosis either via laboratory tests or clinical assessment. Importantly, smell, taste, and chemesthetic function were each significantly reduced compared to their status before the disease. Difference scores (maximum possible change ±100) revealed a mean reduction of smell (-79.7 ± 28.7, mean ± standard deviation), taste (-69.0 ± 32.6), and chemesthetic (-37.3 ± 36.2) function during COVID-19. Qualitative changes in olfactory ability (parosmia and phantosmia) were relatively rare and correlated with smell loss. Importantly, perceived nasal obstruction did not account for smell loss. Furthermore, chemosensory impairments were similar between participants in the laboratory test and clinical assessment groups. These results show that COVID-19-associated chemosensory impairment is not limited to smell but also affects taste and chemesthesis. The multimodal impact of COVID-19 and the lack of perceived nasal obstruction suggest that severe acute respiratory syndrome coronavirus strain 2 (SARS-CoV-2) infection may disrupt sensory-neural mechanisms. © 2020 The Author(s) 2020. Published by Oxford University Press. All rights reserved

Instituitions and Venture Capital: A cross country analysis on OECD countries

Small and Medium Enterprises (SMEs) form the backbone of any economy. However, access to finance remains a key contraint to SME development and thus economic development. The Venture Capital industry has proved to be a good alternative source of financing in some countries to promote innovation and entrepreneurship. Having originated in the USA (a market based economy), it is catching up in Europe particularly in Scandinavian countries through numerous policy initiatives taken by the national governments. However, most continental European economies are traditionally bank-based and the venture capital industry has not been as successful (atleast in the last two decades) compared to USA. Past research in the field attributes this difference in performance to numerous factors but none that provides a detailed and in-depth institutional basis to it. This thesis attempts to find if the venture capital industry is more successful in a particular institutional environment or more specifically a particular kind of economic system.Engineering and Policy AnalysisEconomics of InnovationTechnology, Policy and Managemen

Development of a Two-Scale Turbulence Model and Its Applications

The use of second order closure turbulence model in predicting turbulent flows is known to be more successful than the classical mixing length model. However, it is found that if the turbulence constants are not altered or modified, the second order closure turbulence model is unable to predict satisfactorily f or some flows such as round jet and wake flows. In order to improve the predictability of the second order closure model, the present work proposes to consider two turbulent scales in the modelling of turbulent flows. One of these scales is based on using the turbulent kinetic energy, k, and its dissipation rate, epsilon, to characterize the large energy containing eddies. The other scale is based on the dissipation rate and the kinematic viscosity, nie, to characterize the small energy dissipating eddies. The second scale is based on the well known Kolmogorov hypothesis that dissipation of turbulent kinetic energy occurs primarily at small eddies. The turbulence model derived based on the concept of two different scales is called the two-scale turbulence model. The existing turbulence model which is modelled based on the one-scale concept of k and epsilon is called the one-scale turbulence model. The two-scale turbulence model is then applied to predict turbulent free shear flows and recirculating flows. The calculations were done in three parts. The first test case was nonbuoyant free shear flows which included round and plane jets in stagnant and moving streams, plane wakes and mixing layer. In the second part, the model was tested for plane and round buoyant jets having different Froude numbers. Finally, some results were obtained for recirculating flows, namely, backward facing step and flow past an obstruction. It is shown in the present study that the two-scale turbulence model performs significantly better than the one-scale turbulence model in all the cases concerned. The prediction capability of the two-scale turbulence model is shown since one does not need to alter or modify the turbulence constants as in the case of the one-scale turbulence model

Effect of Arsenic on Photosynthesis, Growth and its Accumulation in the Tissues of Allium cepa (Onion)

Arsenic is a well known carcinogenic element, that can harm not only human health but, plant and bacteria as well. Replicated experiments confirmed that, Arsenic accumulates in the different tissues in different parts of the plant and, adversely affects the growth and productivity of the plants. It is a threat for millions of population in terms of health and food security both. Therefore, a pot experiment was designed and conducted to investigate the effect of arsenic on photosynthetic pigments, Chlorophyll-a and –b, growth behavior, and its accumulation in the tissues of different parts of onion plants (Allium cepa). Test plants were subjected to pot experiment under natural conditions. Four pots were prepared to grow onion plants, irrigated with equal volume of different Arsenic solution (NaAs3), 0.00 mg/l, 0.200mg/l, 0.600mg/l, and 0.800mg/l concentration with one pot for control respectively, throughout the experiments. Both chlorophyll-a and -b contents in onion leaf increased significantly with the increase of water arsenic concentrations. The highest chlorophyll-a (0.004847/g) and chlorophyll-b (0.006528/g) contents were estimated in the onion leaf irrigated with 0.800mg/l of Arsenic whereas, in control plant it was lowest (chl-a 0.002363/ and chl-b 0.004092/g). A high positive correlation was observed between water arsenic (R2= 0.897 and 0.963) & soil arsenic (R2= 0.926 and 0.919) with chlorophyll-a and chlorophyll-b respectively. High positive correlation was also observed even for onion growth verses soil arsenic and water arsenic (R2=0.994 and 0.968) and water Arsenic with leaf biomass (R2=0.973) respectively. However, no Arsenic accumulation was detected in the tissues of different parts of the onion plants suggesting that, arsenic (NaAs3) influenced the 40 K. Singh Sushant and A.K. Ghosh biochemistry of photosynthesis which ultimately resulted in the increase of onion growth and yield. Onion plants can be cultivated in the area where Arsenic containing water is being utilized for irrigating crops but, a chain of in-vitro studies are required to understand the biochemistry and mechanism that influenced growth and productivity of the onion plants.Technology, Policy and Managemen

Robust evidence for the stabilization of the premartensite phase in Ni-Mn-In magnetic shape memory alloys by chemical pressure

The thermodynamic stability of the premartensite (PM) phase has been a topic of extensive investigation in shape memory alloys as it affects the main martensite phase transition and the related physical properties. In general, the PM phase is stable over a rather narrow temperature-composition range. We present here evidence for chemical pressure induced suppression of the main martensite transition and stabilization of the PM phase over a very wide temperature range from 300 to ∼5K in a magnetic shape memory alloy (MSMA), Ni50Mn34In16, using magnetic susceptibility, synchrotron x-ray powder diffraction (SXRPD) studies, and first-principles calculations. The ac-susceptibility studies show a highly skewed and smeared peak around 300 K without any further transition up to the lowest temperature of our measurement (5 K) for ∼5% Al substitution. The temperature evolution of the SXRPD patterns confirms the appearance of the PM phase related satellite peaks at T≤300K without any splitting of the main austenite (220) peak showing preserved cubic symmetry. This is in marked contrast to the temperature evolution of the SXRPD patterns of the martensite phase of the Al free as well as ∼3% Al substituted compositions where the austenite (220) peak shows a clear splitting due to Bain distortion signalling symmetry breaking transition. Our theoretical calculations support the experimental findings and reveal that the substitution at the In site by a smaller size atom, like Al, can stabilize the PM phase with preserved cubic symmetry. Our results demonstrate that Al-substituted Ni-Mn-In MSMAs provide an ideal platform for investigating the physics of various phenomena related to the PM state.Team Marcel Sluite

Modular Quadrotor MAVs

Historically, helicopters with four rotors (quad-rotors) have been very uncommon, mainly due to the fact that most of the common payloads could be lifted using one or two rotors. However, the quad-rotor possesses some special characteristics that make it attractive. One would be the superior payload capacity. Two, is the simplicity of the control system: the absence of complex rotor mechanisms and just by independently adjusting the speed of each rotor it is possible to control both the attitude and the horizontal/vertical motion. This system is particularly suitable for small unmanned aerial vehicles (UAV), because it reduces the complex mechanism of the rotors (saving volume and weight) and simplifies the control algorithms required for stable, untethered flight. Although much progress has been made in the field of quad-rotor UAVs, it is still a great challenge to build a quad-rotor capable of fully autonomous flight. Before the decision of appropriate control algorithms, it is essential to have complete understanding of quad-rotor dynamics and equation of motion. This technical paper presents a detailed quad rotor model design as well as the detailed algorithm for the control system. An ANSYS flow simulation was carried out on the modular structure of the quad rotor. Different sensors were integrated with the control system to improve the stability and to reduce the pilot\u92s workload. Its capabilities will be enhanced with semi-autonomous and autonomous functions that were implemented with the usage of GPS

scTopoGAN: unsupervised manifold alignment of single-cell data

Motivation: Single-cell technologies allow deep characterization of different molecular aspects of cells. Integrating these modalities provides a comprehensive view of cellular identity. Current integration methods rely on overlapping features or cells to link datasets measuring different modalities, limiting their application to experiments where different molecular layers are profiled in different subsets of cells. Results: We present scTopoGAN, a method for unsupervised manifold alignment of single-cell datasets with non-overlapping cells or features. We use topological autoencoders (topoAE) to obtain latent representations of each modality separately. A topology-guided Generative Adversarial Network then aligns these latent representations into a common space. We show that scTopoGAN outperforms state-of-the-art manifold alignment methods in complete unsupervised settings. Interestingly, the topoAE for individual modalities also showed better performance in preserving the original structure of the data in the low-dimensional representations when compared to other manifold projection methods. Taken together, we show that the concept of topology preservation might be a powerful tool to align multiple single modality datasets, unleashing the potential of multi-omic interpretations of cells.Pattern Recognition and Bioinformatic

Unlocking the Potential of Smart Technologies: Addressing Adoption Challenges

Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Engineering, Systems and Service