A novel hanging spherical drop system for the generation of cellular spheroids and high throughput combinatorial drug screening

We propose a novel hanging spherical drop system for anchoring arrays of droplets of cell suspension based on the use of biomimetic superhydrophobic flat substrates, with controlled positional adhesion and minimum contact with a solid substrate. By facing down the platform, it was possible to generate independent spheroid bodies in a high throughput manner, in order to mimic in vivo tumour models on the lab-on-chip scale. To validate this system for drug screening purposes, the toxicity of the anti-cancer drug doxorubicin in cell spheroids was tested and compared to cells in 2D culture. The advantages presented by this platform, such as feasibility of the system and the ability to control the size uniformity of the spheroid, emphasize its potential to be used as a new low cost toolbox for high-throughput drug screening and in cell or tissue engineering.

Dissipative contact force models

"Series: Solid mechanics and its applications, vol. 226"

Obstruction of the left ventricular outflow tract after mitral valvuloplasty with implantation of Gregori's ring

Mitral valvuloplasty is efficient for repairing mitral valve disease with few complications. In some cases, obstruction of the left ventricular outflow tract may occur due to systolic anterior motion of the mitral valve. We report the case of a patient with this complication and a pressure gradient between the left ventricle and the aorta of 130 mm Hg after mitral valvuloplasty with implantation of a Gregori's ring. The management was clinical with suspension of the vasoactive drugs and introduction of a beta-blocker. Two years after the surgery, the patient is asymptomatic and has a normal life.

The appraisal of mesophilic anaerobic digestion and thermophilic aerobic digestion in the treatment of municipal sludge in Ireland

It has been well documented that the optimum feedstock for anaerobic digesters consists of readily biodegradable compounds, as found in primary sludge or even a mixed substrate of primary and excess activated sludge. Due to the requirements of the Urban Wastewater Treatment Plant Directive of 1991, the quantities of secondary sludge generated is set to increase substantially. A pilot scale study was undertaken to evaluate the performance of both Mesophilic Anaerobic Digestion and Thermophilic Aerobic digestion in the treatment of secondary sludge. The results indicated that the anaerobic pilot scale digester achieved a greater solids destruction than the aerobic pilot plant averaging at 28% T.S. removal verses 20% for the aerobic digester, despite the fact that secondary sludge is the optimum feedstock for aerobic digestion. This can, however, be attributed to the greater biomass yield experienced with aerobic systems, and to the absence of Autothermal conditions. At present, the traditional technique of Mesophilic Anaerobic Digestion is in widespread application throughout Ireland, for the stabilisation of sewage sludge. There is only one Autothermal Thermophilic Aerobic Digester at present situated in Killarney, Co. Kerry. A further objectives of the study was to compare full-scale applications of Mesophilic Anaerobic Digestion to ATAD. Two Sludge Treatment plants, situated in Co. Kerry, were used for this purpose, and were assessed mainly under the following headings; process stability, solids reduction on average, the ATAD plant in Killarney has the advantage of producing a “Class A” Biosolid in terms of pathogen reduction, and can effectively treat double the quantity of sludge. In addition, economically the ATAD plant is cheaper to run, costing €190 / t.d.s verses €211 / t.d.s. for the anaerobic digester in Tralee. An overview of additional operational Anaerobic Digestion Plants throughout Ireland is also presented.

The appraisal of anaerobic digestion in Ireland to develop improved designs and operational practice

Mesophilic Anaerobic Digestion treating sewage sludge was investigated at five full-scale sewage treatment plants in Ireland. The anaerobic digestion plants are compared and evaluated in terms of design, equipment, operation, monitoring and management. All digesters are cylindrical, gas mixed and heated Continuously Stirred Tank Reactors (CSTR), varying in size from 130m3 to 800m3. Heat exchanger systems heat all digesters. Three plants reported difficulties with the heating systems ranging from blockages to insufficient insulation and design. Exchangers were modified and replaced within one year of operation at two plants. All but one plant had Combined Heat and Power (CHP) systems installed. Parameter monitoring is a problem at all plants mainly due to a lack of staff and knowledge. The plant operators consider pH and temperature the most important parameters to be measured in terms of successful monitoring of an anaerobic digester. The short time taken and the ease at which pH and temperature can be measured may favour these parameters. Three laboratory scale pilot anaerobic digesters were operated using a variety of feeds over at 144-day period. Two of the pilots were unmixed and the third was mechanically mixed. As expected the unmixed reactors removed more COD by retention of solids in the digesters but also produced greater quantities of biogas than the mixed digester, especially when low solids feed such as whey was used. The mixed digester broke down more solids due to the superior contact between the substrate and the biomass. All three reactors showed good performance results for whey and sewage solids. Scum formation occurred giving operational problems for mixed and unmixed reactors when cattle slurry was used as the main feed source. The pilot test was also used to investigate which parameters were the best indicators of process instability. These trials clearly indicated that total Volatile Fatty Acid (VFA) concentrations was the best parameter to show signs of early process imbalance, while methane composition in the biogas was good to indicate possible nutrient deficiencies in the feed and oxygen shocks. pH was found to be a good process parameter only if the wastewater being treated produced low bicarbonate alkalinities during treatment.

Heterogene Prozesse am Beispiel der Verbrennung fester Stoffe und der Kristallisation aus Lösungen

Heterogeneous processes, solids, combustion, crystallization, kinetics, online-monitoring, gaspotentiometric oxygen sensors, chiral separation, solid/liquid equilibria

Influência de diferentes cavalos e da época de colheita no teor de vitamina C na laranja natal

This paper deals with the variation of the ascorbic acid content in Natal orange as related to the type of rootstock and to the picking time. The determinations were carried out in the juice of fruits which had practically the same ratio total solids/acidity being selected only the highest values of such quotient. The results can be summaryzed as follows: 1. The rootstock has a significant influence on the vitamin C content of the scion; this influence shows two interesting aspects: first, the ascorbic acid contet itself varies as a function of the rootstock; among the three rootstocks studied the highest values were obtained on scion growing on Serra d'água orange; the lowest values were found in "limão rugoso" and "limão francês" was intermediate; the second point to be emphasyzed is the manner of variation of the ascorbic acid content in the different rootstocks: in the case of Serra d'água. the content decreases slowly whereas in "limão francês" the level remains nearly constant and suddenly falls down; finally in the case of "limão rugoso" the amount of ascorbic acid increases significantly to return to the primitive level. 2. The amount of ascorbic acid, not considering the rootstock influence, varies strongly as a function of harvesting time; for this reason the present factor must be borne in mind when sampling for the determination of ascorbic acid in orange is concerned.

O brix na determinação da riqueza em açúcares do mamão como auxiliar no melhoramento do mamoeiro (Carica papaya L.)

There is in the literature a noteworthy lack of sampling methods to be employed in the selection of papaya fruits for genetical improvement purposes. In the present experiment methods applied to melon and watermelon were extended to papaya with good results. The authors tried to correlate the solids content-as determined by a hand refractometer-with total sugars in the fruit. The correlation does exist being significant and positive. A regression equation was worked out; it permits to calculate the total sugar content provided the Brix value determined by the hand refractometer is known. The equation is as follows: a = 0.57 s where a = total amount of sugar as glucose, and s = total solids.

Nitrificação e aproveitamento de alguns adubos nitrogenados

The rate of nitrification of several nitrogenous fertilizers (ammonium sulfate, nitre-chalk, ureia, and cottonseed meal) was studied in three soils, namely, "terra roxa legítima", a red soil derived from basalt, "terra roxa misturada", a soil also derived from basalt but with a higher proportion of sand, and "areito Corumbataí", a sandy soil. The effects of the following treatments on nitrification were considered: addition of limestone of micronutrients (Fe, Cu, Zn, Mn, and Mo), and inoculation with a suspension of spores of Aspergillus wentii, a heterotrophic nitrifier. The results showed that: in "terra roxa legítima" limestone had no influence on the nitrification rate, whereas the micronutrients estimulated the oxidation of nitre-chalk, cottonseed meal and urea; inoculation with A. wentii helped only the nitrification of ammonium sulfate and of the cottonseed meal; the latter, in all the treatments employed gave use to a smaller amount of nitrates; in "terra roxa misturada", all the fertilizers depending upon the treatments they were subjected to, presented maximum values for nitrification; limestone estimulated the oxidation of ammonium sulfate as well as the mineralization of the cottonseed meal; the addition of micronutrients helped the nitrification of all the fertilizers, except that of urea; inoculation showed a benefical influence on the nitrification of ammonium sulfate and cottonseed meal; in "arenito de Corumbatai", the amounts of nitrates produced was roughly the same for all the fertilizers investigated; limestone estimulated the nitrification of nitro-chalk, ammonium sulfate and cottonseed meal whilst the addition of micronutrients benefited only the latter two; the inoculation with A. wentii helped the oxidation of all the fertilizers. In order to study the availability of the various fertilizers above discussed, two plant growing experiments were carried cut, one in pots, using the three soil types and another one in the field, with "terra roxa misturada". In "arenito de Corumbatai" there was no significant difference in the yield both of straw and rice grains for none of the fertilizers: Chilean nitrate of soda was used as a control; ho marked agreement could be detected between the data concerning nitrification and the yield results. In "terra roxa legítima", ammonium sulfate won the competition and there was a good parallelism between nitrification and yield. In "terra roxa misturada", there was no statistical difference among the various fertilizers; the agreement between nitrification and yields was reasonable. In the field (corn), Chilean nitrate, ammonium sulfate and nitro-chalk were clearly beter than urea and cottonseed meal which did not differ from the minus nitrogen plots.

A maturação do abacaxi

In the present work it was sougth to correlate the coloration of the fruit of Ananas comosus variety Perola with the pulp quality, aiming at the orientation of the fruit grower to the correct time of harvest. Pineapple fruit was chosen in 5 stages of maturation recognized by its external characteristics, principally its color. The fruits of each stage of maturation were analysed, determining the. weight, the percentage of soluble solids, and relation of acid to soluble solids. At the same time a test was made classifying the fruits as acid, regular, good, excellent, and spoiled. A correlation was found between the external coloration of the fruit and the degree of maturation. Concluding from this that the best time to harvest the variety Perola is in the third stage in the regions closest to the market and in the second stage in the regions which are farther away. For the cannery industry the fruit should be harvest in the first stage.

Etablierung von Kallus- und Suspensionskulturen bei Tagetes erecta L.

Diese Arbeit soll im Rahmen eines kooperationsforschungsvorhabens des Julius Kühn-Institutes in Quedlinburg und der Technischen Universität Wien einen Beitrag zur Aufklärung des Syntheseweges von gelben Flavonolen in der Pflanzengattung Tagetes leisten. Angesiedelt ist dieses Forschungsvorhaben im Institut für Züchtungsforschung an gartenbaulichen Kulturen (JKI) und im Institut für Verfahrenstechnik, Umwelttechnik und Technische Biowissenschaften (TU Wien). Im Mittelpunkt steht dabei die Aufklärung des Syntheseweges von gelben Flavonolen (Halbwirth et al., 2004). Innerhalb dieses Synthesewegs ist die Hydroxylierung von Quercetin zu Quercetagetin durch das Enzym Flavonol-6-hydroxylase (F6H) von besonderem Interesse. Die für die F6H kodierenden Gene könnten zum Beispiel anhand einer Pflanze lokalisiert werden, die aufgrund einer Mutation keine F6H-Aktivität aufweist. Bisher wurden keine derartigen Mutanten bei Tagetes gefunden. Für Mutationsversuche zur Klärung von Fragen der Biosynthese oder des Abbaus von sekundären Pflanzenstoffen sind Gewebekulturen besonders geeignet (Heß, 1992). Für die weitere Forschung sollen im Rahmen dieser Arbeit Kalluskulturen von den Tagetes erecta-Sorten „Antigua“ und „Bianca“ etabliert werden. Sieben Kulturmedien und vier Explantattypen wurden von der Autorin ausgewählt und sollen hinsichtlich der Kallusinduktion getestet werden. Der Einfluss von drei Belichtungsvarianten auf die Kallusinduktion wird untersucht. Der etablierte Kallus soll in Suspension überführt werden. Die Suspensionskulturen können für molekularbiologische Arbeiten, Mutationsversuche sowie Versuche zur Flavonolsynthese verwendet werden. (...)

Effects of 2-chloroetylphosphonic acid on ripening of mango

Mature fruits of mango 'Paheri' were treated immediately after harvest with ethefon at 0 - 250 - 500 - 1.000 and 2.000 ppm. Fruit ripening was accelerated by all treatments , the time to maturity being reduced from 48 to 72 hours, when compared with controls. Maturation was evaluated, by external colour of fruits, soluble solids and acid contents.

Diversity and structure of microcrustacean assemblages (Cladocera and Copepoda) and limnological variability in perennial and intermittent pools in a semi-arid region, Bahia, Brazil

Temporary wetlands undergo recurrent drought due to the scarcity of water, which disrupts the hydrological connectivity with adjacent aquatic systems. However, some environments retain water for longer periods, allowing greater persistence of the community. The current study evaluated differences in the microcrustacean assemblages and limnological variability between perennial and intermittent pools in a semi-arid region of Brazil. The abiotic features (water temperature, pH, total alkalinity, electrical conductivity and depth) of intermittent pools were affected more than perennial pools due to loss of water volume. This may have contributed to a higher average richness and diversity index in some intermittent pools and differences in the structure of the assemblages. The lowest species richness and diversity were recorded where physical factors, such as a large quantity of suspended solids and variability in the electrical conductivity of the water and pH, make the environment unsuitable for these organisms. These results suggest that community development in intermittent pools is interrupted by the dry season; when the water returns, due to rainfall or rising groundwater, each pond undergoes a different process of colonization. In these circumstances, the biological importance of temporary aquatic environments is clear, since such pools provide shelters and have an important role in the maintenance of the regional diversity of aquatic environments.

Life history, biomass and production of Coronatella rectangula (Branchiopoda, Anomopoda, Chydoridae) from Minas Gerais

Species of Chydoridae provide the main diversity of the Cladocera. These organisms have been the subject of many studies; some dealing with their role in energy flow in aquatic ecosystems, since they inhabit the littoral region of water bodies which undergo the first impacts from anthropic activities. The aim of this study is to increase knowledge about the life cycle of Coronatella rectangula (Sars, 1861), a species found in several water bodies in the state of Minas Gerais, Brazil. The life cycle was determined by the culture of parthenogenetic females under controlled conditions in the laboratory. Experimental cultures were maintained in growth chambers at a constant temperature of 23.6(±0.5)ºC, through a 12 h light/12 h dark photoperiod. The organisms were fed on a suspension of Pseudokirchneriella subcapitata (Chlorophyceae) (10(5) cells.mL-1), and 0.02 mL of a mixed suspension of yeast and fish ration added per organism in equal proportions (1:1). Fifty parthenogenetic females with eggs were isolated and maintained until they produced neonates. Thirty of these neonates that had less than 24 hours were put in polypropylene bottles of 50 mL and kept in a germination chamber. These organisms were observed daily to obtain the parameters of the life cycle. Biomass and secondary production were also calculated. The embryonic development time of the specimens of C. rectangula was 1.68(±0.13) days and the time to reach primipara, was 2.48(±0.45) days. The mean fecundity of C. rectangula was two eggs/female/brood and the total number of eggs produced by the female during its life cycle was 27.8 eggs. During the whole life cycle, specimens of C. rectangula had a maximum of 14 seedlings, with two instars in the juvenile stage. Total biomass for C. rectangula was 36.66 µgDW.m-3(9.83 for the juvenile stage and 26.82 µgDW.m-3 for adults), and secondary production was 12.10 µgDW.m-3.day-1(8.34 µgDW.m-3.day-1 for egg production and 3.76 µgDW.m-3.day-1 for the juvenile stage).

Occurrence of Hirudinea species in a post urban reach of a Patagonian mountain stream

Temporal (May 2005 to February 2006) and habitat distribution (pools and riffles) of Hirudinea species was analyzed at a post urban reach from Esquel stream (Chubut province, Patagonia, Argentina). Site was located 5.7 km downstream a Waste Treatment Plant. Mean values of nutrients: ammonia, nitrates and soluble reactive phosphate, as well water conductivity, turbidity and total suspended solids indicated physical and organic pollution. Leeches assemblage was composed by the glossiphonids: Helobdella scutifera Blanchard, 1900, H. michaelseni (Blanchard, 1900), H. simplex (Moore, 1911), Helobdella sp., H. hyalina Ringuelet, 1942, H. obscura Ringuelet, 1942 and the semiscolecid Patagoniobdella variabilis (Blanchard, 1900). From these H. hyalina and H. obscura are new records for Chubut province. Helobdella hyalina (810 ind.m-2) and H. simplex (465 ind. m-2) clearly dominated the assemblage at the reach. Only H. simplex displayed a spatial preference being significantly more abundant in pools than in riffle habitats (p<0.001). Species recruitment occurred mostly at September, December and March when juveniles were very abundant. Although several species of Helobdella were able to live in the disturbed section of the stream, only H. simplex and H. hyalina sustained large populations at the site and can be considered as tolerant to organic enrichment. This information is valuable to future studies on stream condition assessment in mountainous areas in Patagonia, and in other areas in which these species are present.