Cheap Medium Research Articles

Energetic and exergetic analysis of a domestic water tank with phase change material

Although water is a cheap and effective medium for thermal energy storage, other options are currently being studied, to increase the storage density or to reduce the cost of the storage. The authors have been developing a system which combines the advantages of stratified sensible heat storage and latent, phase change heat storage; i.e. a hot water storage tank with stratification where a phase change material (PCM) is included into a spiral tube installed in the top of the tank. The PCM used was a granular PCM–graphite compound of about 90 vol:% of sodium acetate trihydrate and 10 vol:% graphite. This paper presents the results of an experimental investigation of the performance of the new storage concept, and of a conventional hot water storage tank for comparison. The data are further analysed with respect to the energetic and exergetic performance of the two systems.

Production of cellulases and hemicellulases by Penicillium echinulatum grown on pretreated sugar cane bagasse and wheat bran in solid-state fermentation

To evaluate the solid-state fermentation (SSF) production of cellulase and hemicellulases (xylanases), by Penicillium echinulatum 9A02S1, in experiments carried out with different concentrations of the pretreated sugar cane bagasse (PSCB) and wheat bran (WB). This study reports the production of xylanolytic and cellulolytic enzymes by P. echinulatum 9A02S1 using a cheap medium containing PSCB and WB under SSF. The highest amounts of filter paper activity (FPA) could be measured on mixtures of PSCB and WB (32.89 +/- 1.90 U gdm(-1)). The highest beta-glucosidase activity was 58.95 +/- 2.58 U gdm(-1) on the fourth day. The highest activity for endoglucanases was 282.36 +/- 1.23 U gdm(-1) on the fourth day, and for xylanases the activity was around 10 U gdm(-1) from the second to the fourth day. The present work has established the potential of P. echinulatum for FPA, endoglucanase, beta-glucosidase and xylanase productions in SSF, indicating that WB may be partially substituted by PSCB. The incorporation of cheap sources, such as sugar cane bagasse, into media for the production of lignocellulose enzymes should help decrease the production costs of enzymatic complexes that can hydrolyse lignocellulose residues for the formation of fermented syrups, thus contributing to the economic production of bioethanol.

Integral utilisation of barley husk for the production of food additives

AbstractA new and effective chemical–biotechnological process for the global utilisation of barley husk (obtained from the spent grains in the brewing process) is reported. With the proposed process the three main components of the lignocellulosic residue (cellulose, hemicellulose and lignin) are utilised. A first treatment with sulfuric acid (pre‐hydrolysis) allowed the solubilisation of hemicelluloses to give xylose and glucose‐containing liquors (suitable to make fermentation media for the continuous lactic acid (LA) production with L. pentosus) and a solid phase containing cellulose and lignin. In this set of experiments, a maximum volumetric productivity (QP) = 2.077 g L−1 h−1 and product yield (YP/S) = 0.62 g g−1 were obtained for a dilution rate of 0.01 h−1. The solid residues from pre‐hydrolysis were treated with NaOH in order to increase their cellulase digestibility, and dissolve the lignin content. The cellulose residue was used as substrates for lactic acid production by simultaneous saccharification and fermentation (SSF) in media containing Trichoderma reesei cellulases and Lactobacillus rhamnosus cells using the complete MRS broth or a cheaper medium. In both cases similar LA concentrations and volumetric productivities were achieved (P = 73.4–71.0 g L−1 and QP = 1.28–1.25 g L−1 h−1, respectively), where P is LA concentration. The lignin solution obtained after the alkaline treatment was extracted with ethyl acetate in order to obtain the phenolic components. The extract obtained at pH 3 showed three times more antioxidant activity than the one extracted at pH 12.8, with an EC50 of 1.396 g L−1 for pH 3 and 4.604 g L−1 for pH 12.8. The best extracts showed twice antioxidant activity than BHT. Copyright © 2007 Society of Chemical Industry

A cluster randomized controlled trial to assess the effectiveness of an intervention to educate students about depression

Depression is an important cause of disability worldwide, with many people experiencing their first depressive episode before the age of 18. University students are particularly vulnerable to depression. Depression can be treated successfully in most patients. However, for treatment to be successful, depressed people need to recognize their symptoms as illness, present to medical care, and be aware that effective treatment is available. A thoughtful health campaign might therefore increase the likelihood of successful treatment. A cluster randomized controlled trial was conducted to determine the effectiveness of an educational intervention. A total of 3313 undergraduate students participated in the study. The intervention consisted of postcards and posters on depression and its treatment. The primary outcome was student awareness that depression can be treated effectively. Secondary outcomes included the proportion of students reading the postcards, recognition of symptoms and knowledge of treatments. The postcards were read by 69% of students. Less than half of participants reported that depression could be treated effectively, and there was no evidence of a difference between the intervention and control groups [341 (49.1%) v. 379 (49.7%), difference -0.7, p=0.8, 95% confidence interval (CI) -5.1 to 3.7]. However, intervention group participants were more likely than control group participants to recognize depressive symptoms and to report that antidepressants are not addictive. Many university students lack knowledge about depression and its treatment. Simple and cheap media, such as postcards and posters, might help to improve awareness in areas where current knowledge is low.

Use of sea water as salts source in starch- and soya bean-based media, for the production of Bacillus thuringiensis bioinsecticides

In order to reduce the cost of Bacillus thuringiensis bioinsecticide-process production , a new medium only composed of starch, soya bean and diluted sea water, providing particularly 7.5 g/l NaCl, was optimized. The results obtained with cultures carried out into 1000 ml shake flasks showed 7% improvement of delta-endotoxin production in such cheap medium compared to that containing a mixture of pure minerals instead of sea water. Interestingly, this new formulated medium was shown to be efficient for delta-endotoxin production by several B. thuringiensis strains exhibiting various larvicidal activities towards either Diptera or Lepidoptera. Moreover, the use of such medium for large scale production of bioinsecticides was also evidenced in an automated full controlled 3 l fermenter. So that it was shown that sea water did not affect such requirements and have positive effect on growth, sporulation and delta-endotoxin synthesis. This should contribute to a significant reduction of the cost of B. thuringiensis bioinsecticide production and utilisation.

Stille Reactions with Tetraalkylstannanes and Phenyltrialkylstannanes in Low Melting Sugar‐Urea‐Salt Mixtures

AbstractThe transfer of simple alkyl groups in Stille reactions usually requires special solvents (HMPA) or certain organotin reagents (stannatranes, monoorganotin halides) to be efficient. Using low‐melting mixtures of sugar, urea and inorganic salt as solvent, a fast and efficient palladium‐catalyzed alkyl transfer with tetraalkyltin reagents was observed. The high polarity and nucleophilic character of the solvent melt promotes the reaction. Stille biaryl synthesis using electron‐poor and electron‐rich aryl bromides proceeds with quantitative yields in the sugar‐urea‐salt melt. Catalyst loading may be reduced to 0.001 mol % and the catalyst melt mixture remains active in several reaction cycles. Showing the same or improved performance for Stille reactions than organic solvents and allowing a very simple work up, sugar‐urea‐salt melts are a non‐toxic and cheap alternative reaction medium available in bulk quantities for the catalytic process.

Select what you need: A comparative evaluation of the advantages and limitations of frequently used expression systems for foreign genes

The expression of heterologous proteins in microorganisms using genetic recombination is still the high point in the development and exploitation of modern biotechnology. People can produce bioactive proteins from relatively cheap culture medium instead of expensive extraction. Host cell systems for the expression of heterologous genes are generally prokaryotic or eukaryotic systems, both of which have inherent advantages and drawbacks. An optimal expression system can be selected only if the productivity, bioactivity, purpose, and physicochemical characteristics of the interest protein are taken into consideration, together with the cost, convenience and safety of the system itself. Here, we concisely review the most frequently used prokaryotic, yeast, insect and mammalian expression systems, as well as expression in eukaryote individuals. The merits and demerits of these systems are discussed.

Production of multiple xylanolytic and cellulolytic enzymes by thermophilic fungus Myceliophthora sp. IMI 387099

This study reports the production of xylanolytic and cellulolytic enzymes by a thermophilic fungal isolate Myceliophthora sp. using a cheap medium containing rice straw and chemically defined basal medium under solid-state culture. A combination of one factor at a time approach followed by response surface methodology using Box–Behnken design of experiments resulted in 2.5, 1.25, 1.28 and 4.23 fold increase in xylanase, endoglucanase, β-glucosidase and FPase activity, respectively. The zymograms developed against IEF gels showed that multiple isoforms of xylanase (5), endoglucanase (4) and β-glucosidase (2) were produced under optimized culture conditions. Moreover, thiol containing serine proteases produced during the growth of the culture had no role in the post-translational modification of these xylanases.

Penggunaan Media Alternatif pada Kultur In Vitro Jahe (Zingiber officinale Rosc.) Varietas Gajah

The problem faced in cultivation of ginger is the availability of uniform plant propagation materials. Ginger is propagated through underground rhizomes. Growth of the rhizome is not uniform, since the shoots do not sprout at the same time. Most of the rhizomes were attacked by several diseases such as bacterial wilt, soft rot, and nematodes. Propagation of plant material through in-vitro culture is also an obstacle since the price of pure agar and chemicals is very expensive. Therefore, production of cheap, uniform and disease-free plant materials with rapid multiplication rate is necessary for the successful ginger cultivation. The use of alternative media on in-vitro culture of ginger ( Zingiber officinale Rosc.) cv. Gajah was conducted in order to substitute cheaper alternative media for in-vitro culture of ginger. An experiment using two basic composition of media (MS and liquid fertilizer) and three different types of agar (seaweed, Swallow and Oxoid agar) was done at the Tissue Culture Laboratory of Center for Research and Development of Isotope and Radiation Technology, Jakarta. The result showed that the highest shoot height, number of shoot and leaf was obtained from medium composition of sea weed and MS. Whilst the medium of Oxoid agar and MS produced the longest and the highest number of root. The cheapest medium was found from seaweed and liquid fertilizer composition, whereas the most expensive medium was from Oxoid agar and MS composition. Seaweed and Swallow agar in MS media showed similar growth performance as well as Oxoid agar in development of ginger plantlets. Key words : Media, In-Vitro, Ginger

Palladium-Catalyzed Oxidation of Octyl Alcohols in “Supercritical” Carbon Dioxide

Noble metal catalyzed aerobic oxidation of alcohols to carbonyl compounds or carboxylic acids is an efficient method, but the frequently observed catalyst deactivation and flammability of organic solvents in the case of water-insoluble alcohols limit the application range. We applied “supercritical” (dense) carbon dioxide as the solvent, a cheap and nonflammable medium with fair and tunable solubility in particular for weakly polar water-insoluble alcohols. The experiments were carried out in a continuous fixed bed reactor, over 0.5 wt% Pd/alumina, at 80–140°C and 75–125 bar. A comparative study of oxidation of 1- and 2-octanols to carbonyl compounds, chosen as model reactions, demonstrated that the method is well suited for the partial oxidation of secondary alcohols with molecular oxygen, whereas for primary alcohols the selectivity is low. In the oxidation of 2-octanol the selectivity was excellent (>99.5%) and independent of conversion. No significant catalyst deactivation was observed and the rate in CO2 was higher by a factor of up to 2–4 compared to the rate of oxidation in nitrogen. The complex effects of pressure and oxygen concentration on the reaction rate have been interpreted by studying the phase behavior in a high-pressure view cell under reaction conditions.

Euphorbia hirta leaves and Musa sapientum fruits in culture media for fungi.

Two plant products, Euphorbia hirta leaves and fruits of Musa sapientum, were evaluated as principal ingredients for selective cultivation of fungi. Sapientum glucose agar supported the growth of both dermatophytic, yeast-like, and saprophytic fungi; growth on this medium compared favourably with growth on Sabouraud glucose agar, a standard mycological medium. Sporulation and pigment formation were stronger on sapientum glucose agar than on Sabouraud glucose agar, although fungal growth on the latter was more luxuriant. Addition of Euphorbia extract to mycological media remarkably enhanced fungal growth on the media, and concomitantly suppressed bacterial growth to a similar extent as did antibiotics. The results of this study suggest that Euphorbia sapientum glucose agar can safely be recommended as a cheap and efficient medium for routine isolation of fungi in both clinical and general mycological studies.

Yield and Disease Resistance of Six Tomato Cultivars Grown in Two Media and Three Calcium Concentrations

Calcium has been linked to disease resistance in fruits and vegetables. The effects of calcium nutrition on six hydroponically grown tomato cultivars (`Switch', `Match', `Blitz', `Caruso', `Trust', and `Celebrity') were evaluated in the fall of 1996. Disease resistance and yield were measured for plants grown in either perlite or pine bark mulch. Plants were fertilized with a 5N–11P–26K water-soluble fertilizer solution containing micronutrients and either 60, 120, or 185 mg·L–1 calcium. Disease resistance was determined by measuring disease lesion diameters on mature green harvested fruit 3 to 5 days after inoculating with Botrytis cinerea Pers.: Fr. There was no significant difference in disease when evaluated by medium, cultivar, or calcium treatment. Foliar analysis by Inductively Coupled Argon Plasma Atomic Emission Spectrophotometer (ICAP) indicated that leaf calcium content ranged from 27,000 to 54,000 μg·g–1 dry weight (leaf above fifth flower cluster), but was not significantly different when analyzed by medium, cultivar, or calcium treatment. There was no significant difference in marketable yield due to medium or calcium treatment. Among cultivars, `Trust' had the highest marketable yield at 2.7 kg per plant, which was significantly different from `Celebrity' at 1.6 kg per plant. This experiment suggests that a cheaper medium (pine bark) and lower calcium levels can be utilized in fall tomato production.

Effectiveness of bridging in multiprotocol LANS

The article summarizes experience with a low-performance transparent multiport bridge in a multiprotocol LAN. Bridging improves performance of complex networks. Reliability of the network can be improved as well, in particular when we use the cheaper medium. On the other hand, transparent bridges can cause some problems in multiprotocol networks. Additional filtering based on the analysis of the protocol type and packet type can resolve them.

Mass cultivation of Tetrahymena thermophila yielding high cell densities and short generation times

A cheap medium, composed of skimmed milk powder, yeast extract, and glucose, for mass cultivation of the protozoon Tetrahymena thermophila has been developed. Cell concentrations of 5 x 106 cells/ml and unprecedented short generation times of only 1.4 h were determined in batch cultures. During the exponential phase of growth, daughter cells initiated a new cell division even before the previous division had been completed, resulting in the formation of cell chains. Addition of glucose extended the stationary phase. Using a bench-top fermentor supplied with a digital control unit the utilization of nutrient components in batch culture was monitored. Milk protein and glucose were consumed completely, but lactose only partly.

The Comix Alternative

Comic books, especially if printed in black and white, are a relatively cheap communication and entertainment medium. This means that poor people (including kids) can afford them, and also that small publishers (including kids) can afford to produce them. It thus seems natural that there have always been “alternatives” to the comics published by the big companies with their color printing and Madison Avenue artwork.

Interconnection Costs of Various Substrates-The Myth of Cheap Wire

Silicon has always been considered a dense and cheap medium for making wires, especially when compared with traditional interconnection media on a per interconnection basis. However interconnection costs in all technologies are essentially invariant on a per unit length basis. The advancing scale of integration has allowed active devices to be smaller and closer together, so wiring, both on chip and in systems, has been cheaper because there has been less of it. It is shown that substrate interconnection capability (in inches of wire per square inch of substrate) is the critical factor in achieving compact low-cost systems characterized by high interconnection density. A relationship between the active silicon area of devices on a substrate and the interconnection capability of the substrate is presented.

A new medium for growth and delta-endotoxin production by Bacillus thuringiensis var. kurstaki

The influence of composition of media used for growth and delta-endotoxin production by B. thuringiensis var. kurstaki was studied with the idea of finding a cheap medium for attaining high yields of spore-crystal preparations. A new medium, based on malt sprouts is proposed. Data on growth and bioinsecticidal activity are given. A concentration of 2.1 × 109 spores.ml-1 was attained in a 48 h process. The spore-crystal preparations obtained present a LC50 of 2.18 × 108 spores.g-1 against larvae of Galleria mellonella.

Microfiche-based exercise in clinical microbiology--a valuable assessment technique for teachers and students.

The use of microfiche in a problem-solving exercise in clinical microbiology is described. Microfiche is a very cheap and convenient medium for use with such exercises. Its use in combination with an assessment sheet for staff and students has proved valuable.

A simple and cheap medium for BHK cells in suspended cultures

The growth of BHK cells in suspended cultures in 6 m medium and the amino acid content of this medium were investigated. Results indicated that lactalbumin hydrolyzate (LH) and tryptose phosphate broth (TPB) are the main sources of amino acids and that in the preparation of the medium the defined quantities of amino acids can be omitted. Thus for the propagation of BHK cells a simpler and cheaper medium is proposed. In this simplified medium the same growth rate was obtained as in the complete 6 m medium. Following storage of the simplified medium at 37 °C for 1 month, significant changes in its amino acids content were found and subsequently poor growth was observed. For optimal growth the simplified medium should be stored at 4 °C, or lower.

Medium Suitable for the Cultivation of Meredith's Actinomycete

IN our study of the antibiotic properties of certain Actinomycetes1, it has been one of our endeavours to devise a cheap medium for the growth of these organisms which would contain a minimum of organic and inorganic substances likely to interfere with the extraction of the antibiotic. Of the many varieties of liquid and solid media tested, we have finally adopted the following : Autolysed yeast extract 0.25 percent Glucose 0.5 percent Distilled water to 100 ml. The reaction adjusted to a pH of 6.0 to 7.0. Increasing the yeast extract content of the media beyond 0.25 percent leads to a reduction in antibiotic production.