Mixture Of Medium Research Articles

Interactions between promethazine hydrochloride drug and sodium benzoate hydrotrope mixtures in various solvent media at different temperatures

The current study investigated the mixed micellization of a phenothiazine drug, promethazine hydrochloride (PMT), with the anionic hydrotrope sodium benzoate (NaB) using a conductometric method in three different solvent media: water, 50 mmol.kg−1 sodium chloride (NaCl), and 300 mmol.kg−1 urea (U). Five different temperatures, ranging from 293.15 to 313.15 K, were chosen for the current study of both pure and mixed systems. PMT belongs to a class of drugs known as antihistamines, which are used to treat allergy symptoms. Various physicochemical parameters of both pure and mixed systems (PMT+NaB) were evaluated at different compositions and temperatures, using numerous theoretical models associated with mixed micellization. The attained critical micelle concentration (cmc) and ideal cmc (cmcid) values indicated the formation of mixed micelles due to interactions between the components. The evaluated cmc value for PMT, the minimum hydrotropic concentration (mhc) of NaB, and the cmc value for the PMT+NaB mixture decreased in the NaCl system and increased in the U system compared with these values in the aqueous solution. The cmc values of the studied mixed systems decrease due to an upsurge in the mole fraction (α1) of NaB, indicating the non-ideality of the evaluated solution mixtures. The interaction parameter (β) was negative, revealing that the interaction between the constituents increased with the increasing α1 of NaB in aqueous solution. In the NaCl solution, the β value increased, whereas, in the U solution, the value decreased. The degree of dissociation (g) values decreased by increasing the α1 of NaB in the solution mixture. Various thermodynamic parameters were also evaluated in detail. The activity coefficient values in all cases were below unity, which further indicated the non-ideality of the system. The assessed excess free energy (∆GexRb) of the system was found to be negative in all cases, displaying the stability of the formed mixed micelles. Across the different solvents, their magnitudes were observed in the following order: ∆GexRb in NaCl > ∆GexRb in water >∆GexRb in U. An ultraviolet (UV)-visible study showed a clear interaction between NaB and PMT in the aqueous system. A Fourier-transform-infrared (FT-IR) spectroscopy investigation revealed a shift in the frequency bands of the components due to the interactions between them.

Hydroponic Growth Media (Substrate): A Review

From the reviewed literature, it is observed that scientist’s worked on the various substrate medias used for hydroponic system. They also studied about different combinations of the media and their effect on crop growth. The reviewed literature shows that scientists have studied different organic and inorganic media viz. cocopit, saw dust, rice husk vermiculite, perlite, hydroton, pumice, sand etc. It was also found that these media are not easily, cheaply and locally available for users. Beside this, few scientists studied about physical and chemical properties of media such as particle size, porosity, bulk density, wettability, water holding capacity (WHC), Air filled porosity (AFP), Electrical conductivity, pH of these media. The crop specific suitability of combinations of the different media mixtures were also tested and reported by many scientists. It was revealed from reviewed literature that salinity of media caused linear reduction in the water consumption. The size and shape of particle size distribution are useful for estimating the hydraulic properties of the media The substrate under long cultivation period causes increase of organic matter content and microorganism activity which leads to an increased competition for oxygen in the root environment. The optimal EC levels range from 1.5 to 4.0 dSm-1 according to crop and its sensitivity to different salinity levels. It was also observed that level of growing medium temperature close to that of the surrounding air seems more suitable. The ideal substrate should have a total porosity of over 85 percent. Particles of smaller-sized individual grains have a larger specific surface area.

Increased Flower Production of Calibrachoa x hybrida by the Soil Fungus Mortierella elongata1

Abstract Calibrachoa (Calibrachoa x hybrida) is a highly valued solanaceous flowering ornamental plant, characterized by its drought-hardiness, abundant flowering, and diverse flower colors. Recently, the saprobic soil fungus Mortierella elongata was isolated as a root endophyte from eastern cottonwood (Populus deltoides) and identified as a potential biological amendment for bioenergy and food crops. Two greenhouse experiments were conducted by transplanting rooted cuttings of Calibrachoa cv. ‘Kabloom Deep Blue' into a potting media mixture amended with 1 or 2% volume mix ratio of millet seed colonized with one of four isolates of M. elongata. Plants were assessed weekly for flower production and 86 days post inoculation for leaf/stem, root, and total dry weight. M. elongata strain 624- significantly increased flower production compared to the non-inoculated millet seed controls at 6 and 7 wk post amendment in both experiments. Above and below ground vegetative dry weight for plants grown in potting media mixture amended with M. elongata isolates varied across isolates, fungal amendment concentrations, and experiments. Our results suggest that potting media mixture amended with M. elongata strain 624- can increase flower production of Calibrachoa during peak marketable periods. Index words: Calibrachoa, plant growth promotion, plant reproduction, biological amendment. Species used in this study: Calibrachoa (Calibrachoa x hybrida); Mortierella elongata Linnem.

Growth and yield response of Swiss chard (Beta vulgaris (L.) to media mixture ratios of sand, acacia soil, and goat manure

Northern Namibian soils are predominantly sandy. A mixture of Acacia soils, sandy and goat manure is frequently used for growing various plants. However, the extent to which variations in proportions of these substrates affect growth and yield is not known. The study was conducted at the University of Namibia, Ogongo campus during the period April to August 2020 to determine optimum mixing ratios for sandy, Acacia erioloba soil and goat manure on the growth and yield of Swiss chard. Treatments were Sandy, Acacia soil and goat manure mixed in 5 different ratios of respectively; 1:2:1; 2:3:2; 1:1:1, 2:1:2, 1:1:2 and Acacia soil (control). Samples from each mixture used for pot filling were taken to the soil laboratory for textural analysis. A complete randomized experiment with 8 replications was laid under the University’s shade house. Measured parameters were plant height, leaf area, fresh and dry matter weight and chlorophyll content. Results showed that media was significantly different across all the measured parameters at 1 % probability level. The medium mixture 2:3:2 outperformed the rest of the mixtures in almost all the parameters. The results of the study indicated that acacia soil alone is not optimum for pot filling but must be supplemented with substrate that is rich in mineral content like goat manure. However, the mixing ratio is a key consideration for optimal vegetable production. We recommend the use of media mixture 2:3:2 to improve yield of Swiss chard.

Influence of interpersonal competence on behavioral intention in social commerce through customer-perceived value

Social commerce is a mixture of e-commerce and social media. The purpose of this study is to examine the effect of interpersonal competency on social commerce behavior through customer-perceived value. We adopt the aspects of interpersonal competence questionnaire (ICQ) to investigate its effect on customer-perceived value including utilitarian value, hedonic value, social value, and privacy risk of social commerce. We then analyze primary data collected from 255 active young consumers of college students of full time and part time at a university who have used social media. Our findings show the effect of interpersonal competence on customer-perceived value. Moreover, they also demonstrate the effect of the utilitarian value and social value on behavioral intention toward social commerce, recognizing the importance of functional utility of commerce activities and social utility of social media use in social commerce.

Modification of Tomato Planting Media to Improve the Quality of Farming Urban Vegetables

The Women's Farmer Group, the PKK RT 03, RW 08 Rewwin, Waru, Sidoarjo group has carried out urban farming during the Covid 19 pandemic, but only some residents understand urban farming. The objectives of the activity are: 1) to increase the knowledge and skills of residents in farming turbans, (2) modification of media and irrigation arrangements, 3). Diversification of plant species cultivated to meet the needs of urban communities. Modification of planting media from various material sources as alternative planting. The method of implementation is through socialization and assistance in planting practices to harvest various kinds of vegetables and plant arrangements. The results of the activity show that the residents have been educated and the lifestyle in the agricultural turban has changed. Planting media from a mixture of soil and non-soil (compost, husk, cocopit, manure). The composition of the media mix that will support planting. The composition of the media for young and mature plants is different. The provision of water through drip irrigation is designed 2 times per day, namely in the morning and evening so that it is maintained and efficient. NPK fertilizer is given as basic fertilizer and a follow-up of 20 g / plant is given 4 times. The results of the demonstration plot for growing tomatoes at a pot capacity of 5 kg showed that the mixture of soil media + compost + husk + manure gave the highest and best yield of tomato fruit compared to the media mixture that was not as complete as the material.

Mixed versus layered multi-media filter for simultaneous removal of nutrients and heavy metals from urban stormwater runoff.

Beach closings are a growing concern in coastal regions because of serious public health and economic ramifications due to the presence of pollutants in stormwater runoff. An underground permeable filter system is proposed to treat such stormwater pollution. Selection of filter media that can treat multiple contaminants in stormwater runoff has been a challenging task. This paper investigates the effectiveness of mixed or layered filter media for the removal of mixed contaminants (nutrient and heavy metal) from synthetic stormwater. Sorption experiments were used to assess the ability of the combination of various materials (calcite, zeolite, sand, and iron filings) to remove nutrients and heavy metals. Based on the results of individual removal efficiency, four sets of combinations of media mixtures were prepared: three mixed media conditions and one layered media condition. Mixed media-1, containing higher ratio of calcite, zeolite, and iron filings, was found to achieve the highest removal efficiency of nitrate (96%), Cr (~ 99%), and Cu (~ 99%). Mixed media-2 removed Zn significantly with a removal efficiency higher than 99% due to the sorption capacity of iron filings and both mixed media-2 and 3 showed efficient removal of Ni (~ 94%) in effluent. Layered media was found to be most efficient in Cd removal (~ 99%). All mixture of materials showed more than 99% removal of total phosphorus and Pb. The sorption efficiency of the different mixtures showed that a combination of traditional (sand) and alternative materials (calcite, zeolite, and iron filings) can be used as an effective medium for the treatment of nutrient and heavy metal contaminants commonly found in stormwater.

Evaluation of Some Growth Media Mixtures for Tomato Transplants Production

The seedlings growth media plays a very important role in factory seedling cultivation. High quality growth media could provide healthy and high-quality seedlings for high yield of vegetable crops. This study has attempted to use some agricultural organic wastes and mineral substrates, with differ rent ratios, as growth media mixtures. to select the best growth media, which are suitable for the growth of tomato seedlings (Solanum lycopersicum). Eighteen different (growth media) mixtures were prepared from mineral fraction (sand and vermiculite) and agricultural organic wastes Palme seeds, rice straw and coffee grounds) then compared. Seven growth media mixtures were selected based on the best growth performance of tomato seedlings. The experiment was arranged in a completely randomized design with 7 treatments and 3 replications with 5 observations per treatment. After the seedlings growth period, seedlings were harvested to determine the effect of the growth media mixtures on the different growth parameters (plant dry matter and leaf area) and (percentage of seedlings, fresh weight and chlorophyll content). The Highest seed emergency rate was achieved with T 13, T14 and T 15 mixtures and the next ones were obtained with T2 mixture. The emergency rates of all treatments were higher than control, and the lowest one was control., The results showed that SPAD value (leaf chlorophyll content) of T2 and 15 mixture was biggest for 47.18 and 46.2 followed insignificantly by T 5, T13 and T4, Which were 45.2, 43.55 and 41.96 and value for control was smallest which was 38.33 without significant difference than T 13, T14 and T4. It could be generally noticed that for fresh weight and leaf area characters, mixture of T15 (the commercial media with an addition 15% of date palm seed ground) had the highest values of plant growth and exceed the rest of the formulas followed by a mixture of T13 with a significant difference. Concerning, dry matter content the results indicated that T4, T5 and T2 of growth media mixtures achieved the highest values 11.78, 11.53 and 11.32 % for dry matter without significant difference. On the other hand, the control media mixture gave the lowest value of dry matter of the tomato transplants.

BAGASSE SEBAGAI SALAH SATU ALTERNATIF CAMPURAN MEDIA TANAM PADA LAHAN PEKARANGAN MENUJU KEMANDIRIAN PANGAN KELUARGA DI KABUPATEN BATANGHARI

Teratai is one of the villages located in Muara Bulian District, Batang Hari Regency and is in themiddle of the city, with diverse residents' livelihoods. Almost all housewives and young womenhave a hobby of farming around the plot of the house. The resulting plants can be used as asupport in meeting the needs of daily life, so as to realize food independence in the family. Onealternative is a mixture of planting media is sugarcane bagasse. Sugarcane bagasse contains52.67% water, 55.89% C-organic, N-total 0.25%, 0.16% P2O5, and 0.38% K2O. The method ofactivity is in the form of counseling with the aim of introducing bagasse / bagasse which can beused as an alternative mixture of planting media in the plots and the contents contained therein.The results of the activity do not yet know that bagasse / bagasse can be an alternative mixtureof media and only know if bagasse contains sugar, and is very good as a compost mixture.

Supplement of biochar and vermicompost amendments in coir and peat growing media improves N management and yields of leafy vegetables

A greenhouse trial assessed the effects of biochar and vermicompost as partial substitutes of conventional growing media on leafy vegetables’ yields and changes of NH4+-N and NO3−-N in growing medium and leachates. Six growing media mixtures [(a) coir, (b) coir + biochar, (c) coir + vermicompost, (d) peat, (e) peat +vermicompost, (f) peat + biochar] combined with three nitrogen (N) rates [0% (0 g N·pot−1), 50% (0.5 g N·pot−1), and 100% (1.0 g N·pot−1) commercial recommendation] were arranged in a split-plot design with three replicates. On average, the yield gap between 100% N and 50% N was improved when biochar and vermicompost were used as substitutes of coir (32% and 28% vs. 49%) and peat (14% and 18% vs. 27%). The concentrations of NH4+-N in the leachates for peat + biochar varied between 17.20 and 1.00 mg·L−1. The concentrations of NO3−-N in the leachates varied between 130.0 and 1.0 mg·L−1for coir + vermicompost, and 60 and 1.0 mg·L−1for peat + vermicompost. The residual NO3−-N in peat + biochar growing media and the leachates did not match the changes observed for NH4+-N, and the much lower residual NH4+-N indicates possible NH4+-N retention by biochar and loss through volatilization in the early growth stages. Our results show that partial substitution of peat with biochar and coir with vermicompost maintained acceptable crop yield at 50% N due probably to N supply by vermicompost and decreased residual mineral N and loss by biochar in the leachates which could be beneficial for the environment.

Innovative Communication Learning: Combining TED Talks and Reflective Writing for Nursing Students.

As educational programs compete with online and open courseware, TED (Technology, Entertainment, and Design) Talks provide meaningful complementary content that can be easily integrated into curricula. Evaluate an innovative approach to the standard lecture by combining media mixture with reflective writing. Undergraduate nursing students were asked to view a TED Talk and write a brief narrative reflection as part of their preparation for a communication class. The video and reflective writing assignment were completed by 23/25 (92%) of students. Qualitative analysis of the reflective writing identified three primary themes: Communication as a Foundational Competency, Importance of Empathy, and Professional Role Development. This illustrative talk and narrative exercise provided an interactive learning experience for novice nurses that served as a compelling means to critically reflect on effective health-care communication skills, prior to entry into practice.

Activated carbon column adsorption of compounds that mimic urban stormwater dissolved organic nitrogen.

Nutrients mobilized by stormwater can exacerbate eutrophication in receiving waters. While bioretention systems are increasingly employed to improve stormwater quality, they do not normally incorporate design attributes for removal of dissolved organic nitrogen (DON). Thus, the current study concentrated on continuous column adsorption of stormwater DON using a media mixture of coal activated carbon and quartz sand. Adsorption of eight model organic nitrogenous compounds was studied and only pyrrole showed an appreciable adsorption performance; other organic nitrogen compounds were weakly adsorbed. The breakthrough depth for pyrrole was 88m (equivalent to 4.4m simulated rainfall depth), at a superficial velocity of 61cm/hr and influent DON concentration of 1mgN/L. Subsequent experiments revealed that adsorption of pyrrole was minimally affected by superficial velocity, such that its DON removal efficiency was greater than 91% for all tested superficial velocities (7-489cm/hr). Accordingly, adsorption processes may be employed for removing stormwater DON fractions behaving similarly to pyrrole; data suggest DON removal initially at greater than 95%, gradually falling to 30% through 25years of service. PRACTITIONER POINTS: Adsorption of eight different organic nitrogenous compounds onto coal-based activated carbon was investigated. Amino acids and an amino sugar were weakly adsorbed onto the activated carbon. Pyrrole, a moderately hydrophobic heterocyclic organic nitrogen compound was effectively adsorbed. A 30-cm depth was considered as adequate for removal of pyrrole and compounds that would similarly adsorb. Evidence of biological ammonification was present in all studies except for pyrrole.

Effect of types of control materials in a modified sedimentation equipment batch laboratory scale

The purpose of this research is to be able to recognize laboratory scale sedimentation devices in the process of deposition through batch system experiments in a cylindrical tub, to explain how the relationship between time, height of deposition and concentration of various solids with sedimentation rates, can compare the precipitating materials used in the sedimentation process both manually and automatically, and can determine the performance of tools and sedimentation rates by using a variety of sedimentation and flocculant materials used in the sedimentation process both without the addition of flocculants or with the addition of flocculants. In supporting this research, the method used is experimentation and analysis. The sample is a mixture of media that is water - depositional material (solids) where the depositional material has previously been sieved and cleaned of impurities and the variables analyzed were deposition time, deposition height, suspension concentration and concentration of flocculant addition. the settling material used varies, among others: 50 grams, 100 grams, 150 grams, 200 grams, and 250 grams, then put into a settling tube. While the results can be obtained from visualization data that is based on more accurate observations and data processing conditions (measurements) obtained in the form of the influence of time on settling rate, the influence of sedimentation column height on settling rate and the effect of solid concentration on settling rate. From the results obtained from various settling materials, the settling speed for CaCO3 precipitates without flocculants and with flocculants is 4.43 cm / minute and 3.86 cm / minute. For the settling speed for tapioca flour depositor without flocculant and with flocculant is 23.64 cm / minute and 23.47 cm / minute. And for settling speed for dry soil sedimentation material without flocculant and with flocculant is 18.60 cm / minute and 15.10 cm / minute and for settling speed of active carbon precipitation material without flocculant and with flocculant is 7.76 cm / minute and 7 .05 cm / minute.

Selection of Peanut Skin as a Growing Medium for Moon Orchid (Phalaenopsis amabilis)

Ferns are a planting medium that is commonly used in Phalaenopsis cultivation, but the growing demand for fern will increase the selling price and the availability of fern is limited. So a solution is needed to reduce the maintenance and maintenance costs by utilizing peanut shells as a growth medium. The purpose of this study is: 1. To determine the effect of peanut skin media on the growth of Phalaenopsis amabilis month orchid 2. To find out better which influence between fern media, fern media plus peanut skins, or peanut skin media on orchid growth month of Phalaenopsis amabilis. When the research began in May 2019 until October 2019. The research object was in the form of a 4-5 month-old orchid, the research location in the Biology Laboratory of the Faculty of Veterinary Science, Bangun Nusantara University, Sukoharjo. Simple randomized study design with three treatments. Treatment A by giving fern media, treatment B by giving fern media mixed with peanut skin, and treatment C by giving peanut skin media. The research variables are the number of leaves, leaf length, leaf area, number of roots and root length measured once a week for 8 weeks. Data analysis with 2. Variance Test (Anova or Kruskal Wallis test) 3. Duncan Multiple Range Test (DMRT) or Moods Median Test. From the results of the study it was found that all observed growth variables (number of leaves, leaf width, leaf length, leaf area, number of roots, average root length, and wet weight) were treated with fern, mixed (Fern and peanut shell) media, and media of peanut skin, there was no significant difference in the effect on the growth of the month orchid. Which means that the three types of media both have an influence on the growth of Phalaenopsis amabilis month orchids. media ferns and peanut shells have their advantages and disadvantages of each. So it can be concluded that, 1. The use of peanut skin media can affect the growth of Phalaenopsis amabilis month orchids. 2. Media fern, a mixture of fern media and peanut skins, and peanut skin media can provide the same effect on the growth of Phalaenopsis amabilis month orchids. From the results of the study it can be recommended that peanut skins can be used as a medium or a mixture of growing media of Phalaenopsis amabilis orchids.

Enhanced proliferative capacity of human preadipocytes achieved by an optimized cultivating method that induces transient activity of hTERT

Human mesenchymal stromal cells (MSC) are an important tool for basic and translational research. Large amounts of MSC are required for in vitro and in vivo studies, however, the limited life-span and differentiation ability in vitro hamper their optimal use. Here we report that 1:1 mixture of L15 and mTeSR1 culture media increased the life-span of IPI-SA3-C4, a normal non-immortalized human subcutaneous preadipocyte strain by 20% while retaining their adipogenic capacity and stable karyotype. The increased proliferative capacity was accompanied by increased expression of the stem markers POU5F1, SOX2, MYC and hTERT, and inhibition of hTERT activity abolished the growth advantage of L15-mTeSR1. Consequently, the described MSC culture would considerably enhance the utility of MSC for in vitro studies.

Response of different media and IBA on shoot sprouting and growth of hardwood cutting in pomegranate (Punica granatum L.) cv. Bhagwa

The field experiment entitled “Response of different media and IBA on rooting and survival of hardwood cutting in pomegranate (Punica granatum L.) cv. Bhagwa” was carried out at Fruit Research Station, Madhadi Baug Farm, Department of Horticulture, College of Agriculture, Junagadh Agricultural University, Junagadh during 2015-16. The experiment was laid out in a Completely Randomized Design with Factorial concept by three repetitions. The treatment consist of five level of different media M1 (soil), M2 [soil + FYM (1:1)], M3 [soil + perlite (1:1)], M4 [soil + sand + FYM (1:1:1)] and M5 [soil + FYM + perlite (1:1:1)] and three level of IBA concentration I1 (IBA 2000 ppm), I2 (IBA 2500 ppm) and I3 (IBA 3000 ppm). The mixture of media influenced on minimum days to shoot sprouting (8.78 days), maximum sprouting percentage (88.90%) at 30 DAP, number of leaves per main shoot (25.84, 57.68 and 90.40), number of shoots per cutting (6.32, 6.87 and 7.17), length of main shoot per cutting (23.71 cm, 33.47 cm and 51.56 cm), thickness of main shoot per cutting (1.18 mm, 2.35 mm and 3.38 mm). Among the factor IBA, I3 (IBA 3000 ppm) recorded significantly the minimum days to shoot sprouting (7.82 days), maximum sprouting percentage (89.77%) at 30 DAP, number of leaves per main shoot (33.34, 63.73 and 101.05), number of shoots per cutting (5.68, 6.60 and 6.83), length of main shoot per cutting (20.94 cm, 29.08 cm and 45.82 cm), thickness of main shoot per cutting (1.12 mm, 2.24 mm and 3.42 mm) at 30, 60 and 90 DAP, respectively. The interaction effect between the media and IBA were found significant in parameters like; maximum sprouting percentage (95.96%) at 30 DAP, maximum number of leaves per main shoot (39.53, 70.29 and 108.20), length of main shoot per cutting (26.73 cm, 37.40 cm and 56.11 cm) at 30, 60 and 90 DAP, respectively. The interaction effect between the different media and IBA were found non significant in parameters like; days to shoot sprouting, thickness of main shoots per cutting and number of shoots per cutting.

Heat and mass transfer effect on an unsteady MHD radiative chemically reactive Casson fluid over a stretching sheet in porous medium

AbstractThe objective of the present study is to investigate the effects of the variable magnetic field, chemical reaction, thermal radiation, Soret effect, and variable heat absorption on the fluid flow and heat and mass transfer of an unsteady Casson fluid past a stretching surface in a saturated porous medium. Velocity slip near the plate and conjugate heating boundary conditions in heat and mass transfer have been considered in this study. Due to the complexities in boundary conditions, the analytic solution of the governing equations of the present model is not possible. Thus, to overcome these issues, the coupled partial differential equations of the model are converted into a set of ordinary differential equations using similarity transformation. These equations have then been solved numerically using the fourth‐order Runge‐Kutta technique via the shooting method. The effects of various pertinent flow parameters on the velocity, concentration, and temperature field have been studied graphically. For the field of engineering, to get an insight into the physical quantities, especially Nusselt number, Sherwood number, and skin friction, their numerical values have been estimated against various parameters and presented in tables. From the tabulated values, it has been perceived that the shear stress increases with an increase in magnetic parameter, unsteadiness parameter, Casson parameter, and heat source parameter, whereas the Biot number shows the reverse trend. The mixture of porous media has justified that the heat transport process over a stretching sheet results in averting heat loss and accelerating the process of cooling, which is a significant outcome of the study. Furthermore, it has also been revealed that with the increase in the Soret effect and magnetic field, there is a reduction in the fluid velocity and temperature near the plate, whereas there is an increase in the species concentration. It has also been mentioned that the effects of the variable magnetic field have been widely applied in various engineering applications like magnetohydrodynamic (MHD) propulsion forces, rate of cooling, MHD power generation, and so on.

Protecting children from iatrogenic harm during COVID19 pandemic.

Critical care management of patients with COVID‐19 has been influenced by a mixture of public, media and societal pressure, as well as clinical and anecdotal observations from many prominent researchers and key opinion leaders. These factors may have affected the principles of evidence‐based medicine and encouraged the widespread use of non‐tested pharmacological and aggressive respiratory support therapies, even in intensive care units (ICUs). The COVID‐19 pandemic has predominantly affected adult populations, while children appear to be relatively spared of severe disease. Notwithstanding, paediatric intensive care (PICU) clinicians may already have been influenced by changes in practices of adult ICUs, and these changes may pose unintended consequences to the vulnerable population in the PICU. In this article, we analyse several potential iatrogenic causes of the detrimental effects of the current pandemic to children and highlight the risks underlying a sudden change of clinical practice.

BNNmix: A new approach for predicting the mixture toxicity of multiple components based on the back-propagation neural network

The chemical mixtures in various environmental media not only have concentration diversity but also mixture-ratio diversity. It is impossible to experimentally determine the toxicities of all mixtures; therefore, it is necessary to develop effective methods based on models to predict mixture toxicity. In this study, a new approach (BNNmix) based on the back-propagation neural network (BPNN) was developed and used to predict the toxicities of seven-component mixtures (consisting of two substituted phenols, two pesticides, two ionic liquids, and one heavy metal) on Caenorhabditis elegans. We found that the combined toxicities of various mixtures used in the experiments were neither global concentration-additive nor global response-additive, which implied that it was impossible to accurately predict the toxicities of such mixtures by using common models such as concentration addition (CA) and response addition (independent action, IA). Using the BNNmix approach to estimate or predict the toxicities of the mixtures under test, it was found that the predictive toxicities of various mixtures with different mixture ratios and concentrations were almost in accordance with those observed experimentally. Unlike the CA and IA models, the BNNmix approach can predict not only the toxicities of mixtures having toxicological interactions but also those with global concentration or response additivities.

Abstract B32: Impact of cancer-associated fibroblasts on head and neck cancer stem cells

Abstract Background: The tumor microenvironment (TME) is made up of epithelial cancer cells and mesenchymal stromal cells including tumor-infiltrating lymphocytes, cancer-associated fibroblasts (CAFs) and endothelial cells. Within the cancer cell population are cancer stem cells (CSC), a subpopulation of cells defined as having the capacity for self-renewal, tumorigenesis, and the ability to recapitulate a heterogeneous tumor. The interaction of the TME with cancer cells remains of interest. The focus of this study is to investigate the effect of patient-derived CAFs on head and neck CSC and tumor activity. Methods: Patient-derived head and neck cancer cell lines and patient-derived fibroblasts lines have previously been established by our group. Tumor cells were grown alone or in combination with patient-matched fibroblasts in a coculture chamber system, allowing for mixture of media but not cells. Scratch tests were performed and closure rates were compared between the two conditions (tumor cells alone and coculture). Tumor cells were then grown alone or in direct contact with matched fibroblasts for one week. Cancer cells were selected for based on epithelial cell adhesion molecule (EpCAM) status and in vitro tumor growth and stem cells percentages (defined as proportion of CD44-high and ALDH-positive cells) were calculated. Results: Patient-derived cancer cells cocultured with matched fibroblasts showed a significant increase in closure rates compared with tumor cells alone at three defined time points (p=0.03-0.002). Coculture conditions resulted in greater in vitro tumor growth after one week (6.4-fold vs. 3.7-fold increase) and an increased proportion of CD44-high tumor cells (9% vs. 5%). The effect of coculture on ALDH-positive percentages was variable. Conclusion: CAFs have previously been shown to potentiate tumorigenesis and metastases. We validated these findings with matched patient derived tumor cells and CAFs. We were then able to demonstrate that CAFs increase the proportion of head and neck CSC, suggesting the mechanism for CAF-associated increased tumor activity may be mediated through CSC. Further studies investigating the relationship between CAFs and CSC are warranted. Citation Format: Molly E. Heft Neal, John Henry J. Owen, Matthew E. Spector, Thomas E. Carey, Mark E.P. Prince, Steven B. Chinn. Impact of cancer-associated fibroblasts on head and neck cancer stem cells [abstract]. In: Proceedings of the AACR-AHNS Head and Neck Cancer Conference: Optimizing Survival and Quality of Life through Basic, Clinical, and Translational Research; 2019 Apr 29-30; Austin, TX. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(12_Suppl_2):Abstract nr B32.