Prediction of culture performance of juvenile Litopenaeus vannamei by in vitro (pH-stat) degree of feed protein hydrolysis with species-specific enzymes

Rapid in vitro methods for measuring digestibility may be useful in analysing aqua feeds if the extent and limits of their application are clearly defined. The pH-stat protein digestibility routine with shrimp hepatopancreas enzymes was previously related to apparent protein digestibility with juvenile Litopenaeus vannamei fed diets containing different protein ingredients. The potential of the method to predict culture performance of shrimp fed six commercial feeds (T3, T4, T5, T6, T7 and T8) with 350 g kg(-1) declared crude-protein content was assessed. The consistency of results obtained using hepatopancreas enzyme extracts from either pond or clear water-raised shrimp was further verified in terms of reproducibility and possible diet history effects upon in vitro outputs. Shrimps were previously acclimated and then maintained over 56 days (initial mean weight 3.28 g) on each diet in 500-L tanks at 114 ind m(-2), clear water closed system with continuous renewal and mechanical filtering (50 mu m), with four replicates per treatment. Feeds were offered four times daily (six days a week) delivered in trays at feeding rates ranging from 4.0% to 7.0% of stocked shrimp biomass. Feed was accessible to shrimp 4 h daily for 1-h feeding period after which uneaten feed was recovered. Growth and survival were determined every 14 days from a sample of 16 individuals per tank. Water quality was monitored daily (pH, temperature and salinity) and managed by water back flushing filter cleaning every 7-10 days. Feeds were analysed for crude protein, gross energy, amino acids and pepsin digestibility. In vitro pH-stat degree of protein hydrolysis (DH%) was determined for each feed using hepatopancreas enzyme extracts from experimental (clear water) or pond-raised shrimp. Feeds resulted in significant differences in shrimp performance (P < 0.05) as seen by the differences in growth rates (0.56-0.98 g week(-1)), final weight and feed conversion ratio (FCR). Shrimp performance and in vitro DH% with pond-raised shrimp enzymes showed significant correlation (P < 0.05) for yield (R-2 = 0.72), growth rates (R-2 = 0.72-0.80) and FCR (R-2 = -0.67). Other feed attributes (protein : energy ratio, amino acids, true protein, non-protein nitrogen contents and in vitro pepsin digestibility) showed none or limited correlation with shrimp culture performance. Additional correlations were found between growth rates and methionine (R-2 = 0.73), FCR and histidine (R-2 = -0.60), and DH% and methionine or methionine+cystine feed contents (R-2 = 0.67-0.92). pH-stat assays with shrimp enzymes generated reproducible DH% results with either pond (CV <= 6.5%) or clear water (CV <= 8.5%) hepatopancreas enzyme sources. Moreover, correlations between shrimp growth rates and feed DH% were significant regardless of the enzyme origin (pond or clear water-raised shrimp) and showed consistent R-2 values. Results suggest the feasibility of using standardized hepatopancreas enzyme extracts for in vitro protein digestibility.

An algorithm for the strip packing problem using collision free region and exact fitting placement

The irregular shape packing problem is approached. The container has a fixed width and an open dimension to be minimized. The proposed algorithm constructively creates the solution using an ordered list of items and a placement heuristic. Simulated annealing is the adopted metaheuristic to solve the optimization problem. A two-level algorithm is used to minimize the open dimension of the container. To ensure feasible layouts, the concept of collision free region is used. A collision free region represents all possible translations for an item to be placed and may be degenerated. For a moving item, the proposed placement heuristic detects the presence of exact fits (when the item is fully constrained by its surroundings) and exact slides (when the item position is constrained in all but one direction). The relevance of these positions is analyzed and a new placement heuristic is proposed. Computational comparisons on benchmark problems show that the proposed algorithm generated highly competitive solutions. Moreover, our algorithm updated some best known results. (C) 2012 Elsevier Ltd. All rights reserved.

Leakage of Saliva Through the Implant-Abutment Interface: In Vitro Evaluation of Three Different Implant Connections Under Unloaded and Loaded Conditions

Purpose: Bacterial leakage along the implant-abutment interface, with consequent species harboring the inner parts of two-part dental implant systems, has been reported in the literature. The aim of this in vitro study was to evaluate bacterial leakage from human saliva to the internal part of the implants along the implant-abutment interface under loaded and unloaded conditions using DNA Checkerboard. Materials and Methods: Sixty denial implants-20 each of external-hexagon, internal-hexagon, and Morse cone-connection designs-and their conical abutments were used in this study. Each group was subdivided into two groups of 10 loaded and 10 unloaded implants. The assemblies were immersed in human saliva and either (1) loaded with 500,000 cycles at 120 N (experimental group) or (2) incubated in static conditions for 7 days at 35 degrees C (unloaded control group). Results: Microorganisms were found in the internal surfaces of all types of connections. The Morse cone connection presented the lowest count of microorganisms in both the unloaded and loaded groups. Loaded implants presented with higher counts of microorganisms than unloaded implants for external- and internal-hex connections. Conclusion: Bacterial species from human saliva may penetrate along the implant-abutment interface under both unloaded and loaded conditions for all connections evaluated. Morse cone-connection implants showed the lowest counts of microorganisms for both conditions. External- and internal-hex implants showed a higher incidence of bacteria and higher bacterial counts after simulated loading. INT J ORAL MAXILLOFAC IMPLANTS 2012;27:551-560.

Development of albendazole sulfoxide-loaded Eudragit microparticles: A potential strategy to improve the drug bioavailability

Albendazole sulfoxide (ABZSO), a broad spectrum anthelmintic drug extensively used in veterinary medicine, exhibits a low and erratic bioavailability due to its poor solubility in biological fluids. The aims of this study were the development, physicochemical characterization, and in vitro release profile evaluation of ABZSO-loaded Eudragit RS PO (R) microparticles (MPs) in order to improve the rate of dissolution and the dissolved percentage of the drug in pH 7.4. MPs were successfully obtained by the emulsification/solvent evaporation method, achieving entrapment efficiency and process yield of about 60% and mean size of 254 nm. The in vitro release profile study showed that dissolution of ABZSO followed a pseudo-second order kinetics and MPs were able to increase significantly (p < 0.05) the rate of dissolution of ABZSO compared to the micronized and non-micronized free drug, what could lead to an improvement in bioavailability and, consequently, in the antiparasitic activity. (C) 2011 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.

Phenol degradation in an anaerobic fluidized bed reactor packed with low density support materials

The objective of this research was to study phenol degradation in anaerobic fluidized bed reactors (AFBR) packed with polymeric particulate supports (polystyrene - PS, polyethylene terephthalate - PET, and polyvinyl chloride - PVC). The reactors were operated with a hydraulic retention time (HRT) of 24 h. The influent phenol concentration in the AFBR varied from 100 to 400 mg L-1, resulting in phenol removal efficiencies of similar to 100%. The formation of extracellular polymeric substances yielded better results with the PVC particles; however, deformations in these particles proved detrimental to reactor operation. PS was found to be the best support for biomass attachment in an AFBR for phenol removal. The AFBR loaded with PS was operated to analyze the performance and stability for phenol removal at feed concentrations ranging from 50 to 500 mg L-1. The phenol removal efficiency ranged from 90-100%.

Effect of Feed Strategy on Methane Production and Performance of an AnSBBR Treating Effluent from Biodiesel Production

The aim of this work was to investigate the effect of different feeding times (2, 4 and 6 h) and applied volumetric organic loads (4.5, 6.0 and 7.5 gCOD L-1 day(-1)) on the performance of an anaerobic sequencing batch biofilm reactor (AnSBBR) treating effluent from biodiesel production. Polyurethane foam cubes were used as inert support in the reactor, and mixing was accomplished by recirculating the liquid phase. The effect of feeding time on reactor performance showed to be more pronounced at higher values of applied volumetric organic loads (AVOLs). Highest organic material removal efficiencies achieved at AVOL of 4.5 gCOD L-1 day(-1) were 87 % at 4-h feeding against 84 % at 2-h and 6-h feeding. At AVOL of 6.0 gCOD L-1 day(-1), highest organic material removal efficiencies achieved with 4-h and 6-h feeding were 84 %, against 71 % at 2-h feeding. At AVOL of 7.5 gCOD L-1 day(-1), organic material removal efficiency achieved with 4-h feeding was 77 %. Hence, longer feeding times favored minimization of total volatile acids concentration during the cycle as well as in the effluent, guaranteeing process stability and safety.

Ractopamine as a Metabolic Modifier Feed Additive for Finishing Pigs: A Review

The beta-adrenergic agonist ractopamine is increasingly used in the swine industry due to higher consumer demand for leaner pork products. Redirecting nutrients to favor leanness rather than fat deposition, ractopamine improves growth and carcass traits of finishing pigs. However, the impact of this agonist on pork quality is not clearly defined. Understanding the biological effects of dietary ractopamine dose, treatment period, lysine levels, and the lysine to metabolizable energy ratio will help pork producers achieve improvements in animal performance, carcass leanness, and economic efficiency in swine production systems.

Study of quercetin-loaded liposomes as potential drug carriers: in vitro evaluation of human complement activation

Liposomes have been employed as potential drug carriers. However, after their in vivo administration, they can be destabilized by proteins of complement system, contributing to the clearance of vesicles from blood circulation. Antioxidant flavonoids such as quercetin have been reported to be beneficial to human health, but their low water solubility and bioavailability limit their enteric administration. Therefore, the development of appropriate flavonoid-carriers could be of great importance to drug therapy. The aim of the present study was to evaluate the activation of human complement system proteins by liposomes composed of soya phosphatidylcholine (SPC) and cholesterol (CHOL) or cholesteryl ethyl ether (CHOL-OET) loaded with quercetin or not. The consumption of complement, via classical (CP) and alternative (AP) pathways, by different vesicles was evaluated using a hemolytic assay and quantitative determination of iC3b and natural antibodies deposited on empty liposomal surfaces by ELISA. The main results showed that empty liposomes composed of large amounts of CHOL consumed more complement components than the others for both CP and AP. Furthermore, replacement of CHOL with CHOL-OET reduced complement consumption via both CP and AP. Incorporation of quercetin did not change CP and AP consumption. Deposition of iC3b, IgG and IgM in vesicles composed of SPC: CHOL-OET at a molar ratio of 1.5:1 was lower compared to the others. Taken together, these observations suggest that liposomes composed of SPC: CHOL-OET at a molar ratio of 1.5:1 are the most appropriate among the vesicles studied herein to be used as a drug carrier system in further investigations.

In vitro cytotoxicity of Selol-loaded magnetic nanocapsules against neoplastic cell lines under AC magnetic field activation

The goals of this study are to evaluate in vitro compatibility of magnetic nanomaterials and their therapeutic potential against cancer cells. Highly stable ionic magnetic fluid sample (maghemite, gamma-Fe2O3) and Selol were incorporated into polymeric nanocapsules by nanoprecipitation method. The cytotoxic effect of Selol-loaded magnetic nanocapsules was assessed on murine melanoma (B16-F10) and oral squamous cell carcinoma (OSCC) cell lines following AC magnetic field application. The influence of different nanocapsules on cell viability was investigated by colorimetric MTT 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay. In the absence of AC magnetic field Selol-loaded magnetic nanocapsules, containing 100 mu g/mL Selol plus 5 x 10(12) particle/mL, showed antitumoral activity of about 50% on B16-F10 melanoma cells while OSCC carcinoma cells demonstrated drug resistance at all concentrations of Selol and magnetic fluid (range of 100-500 mu g/mL Selol and 5 x 10(12) -2.5 x 10(13) particle/mL). On the other hand, under AC applied fields (1 MHz and 40 Oe amplitude) B16-F10 cell viability was reduced down to 40.5% (+/- 3.33) at the highest concentration of nanoencapsulated Selol. The major effect, however, was observed on OSCC cells since the cell viability drops down to about 33.3% (+/- 0.38) under application of AC magnetic field. These findings clearly indicate that the Selol-loaded magnetic nanocapsules present different toxic effects on neoplastic cell lines. Further, the cytotoxic effect was maximized under AC magnetic field application on OSCC, which emphasizes the effectiveness of the magnetohyperthermia approach. (C) 2012 American Institute of Physics. [doi: 10.1063/1.3680541]

Exogenous Administration of 15d-PGJ(2)-Loaded Nanocapsules Inhibits Bone Resorption in a Mouse Periodontitis Model

The 15-deoxy-(Delta 12,14)-PG J(2) (15d-PGJ(2)) has demonstrated excellent anti-inflammatory results in different experimental models. It can be used with a polymeric nanostructure system for modified drug release, which can change the therapeutic properties of the active principle, leading to increased stability and slower/prolonged release. The aim of the current study was to test a nano-technological formulation as a carrier for 15d-PGJ(2), and to investigate the immunomodulatory effects of this formulation in a mouse periodontitis model. Poly (D, L-lactide-coglycolide) nanocapsules (NC) were used to encapsulate 15d-PGJ(2). BALB/c mice were infected on days 0, 2, and 4 with Aggregatibacter actinomycetemcomitans and divided into groups (n = 5) that were treated daily during 15 d with 1, 3, or 10 mu g/kg 15d-PGJ(2)-NC. The animals were sacrificed, the submandibular lymph nodes were removed for FACS analysis, and the jaws were analyzed for bone resorption by morphometry. Immunoinflammatory markers in the gingival tissue were analyzed by reverse transcriptase-quantitative PCR, Western blotting, or ELISA. Infected animals treated with the 15d-PGJ(2)-NC presented lower bone resorption than infected animals without treatment (p < 0.05). Furthermore, infected animals treated with 10 mu g/kg 15d-PGJ(2)-NC had a reduction of CD4(+)CD25(+)FOXP3(+) cells and CD4/CD8 ratio in the submandibular lymph node (p < 0.05). Moreover, CD55 was upregulated, whereas RANKL was downregulated in the gingival tissue of the 10 mu g/kg treated group (p < 0.05). Several proinflammatory cytokines were decreased in the group treated with 10 mu g/kg 15d-PGJ(2)-NC, and high amounts of 15d-PGJ(2) were observed in the gingiva. In conclusion, the 15d-PGJ(2)-NC formulation presented immunomodulatory effects, decreasing bone resorption and inflammatory responses in a periodontitis mouse model. The Journal of Immunology, 2012, 189: 1043-1052.

Preparation and characterization of chloroaluminum phthalocyanine-loaded solid lipid nanoparticles by thermal analysis and powder X-ray diffraction techniques

Solid lipid nanoparticles (SLN) without drug and SLN loaded with chloroaluminum phthalocyanine (AlClPc) were prepared by solvent diffusion method in aqueous system and characterized by thermal analyses and X-ray diffraction (XRD) in this study. Determination of particle size, zeta potential (ZP), and encapsulation efficiency were also evaluated. SLN containing AlClPc of nanometer size with high encapsulation efficiency and ZP were obtained. The results indicated that the size of SLN loaded with AlClPc is larger than that of the inert particle, but ZP is not changed significantly with incorporation of the drug. In differential scanning calorimetry (DSC) curves, it was observed that the melting point of stearic acid (SA) isolated and in SLN occurred at 55 and 64 degrees C, respectively, suggesting the presence of different polymorphs. DSC also shows that the crystallinity state of SLN was much less than that of SA isolated. The incorporation of drug in SLN may have been favored by this lower crystallinity degree of the samples. XRD techniques corroborated with the thermal analytic techniques, suggesting the polymorphic modifications of stearic acid.

In vitro evaluation of combined hyperthermia and photodynamic effects using magnetoliposomes loaded with cucurbit[7]uril zinc phthalocyanine complex on melanoma

The aims of this study were two fold; to develop magnetoliposomes (MLs) loaded with zinc phthalocyanine (ZnPc) complexed with cucurbituril (CB) (CB:ZnPc-MLs) and to evaluate their in vitro photodynamic (PD) and/or hyperthermia (HT) effects while using melanoma cells (B16-F10) as model. The liposomal formulations were characterized by both average diameter and zeta potential. The vesicle average size ranged from 150 to 200 nm and the polydispersity index (PdI) from 0.093 to 0.230. The zeta potential was significantly positive with values between 48 and 57 mV. The cell viability (CV) after PD and HT treatments was assessed by colorimetric MTI method. Melanoma cells were initially treated with the liposome formulation without light and magnetic field application, revealing cell viability not different from the control cells (p > 0.05). Photodynamic and hyperthermia assays were also applied separately, demonstrating that PD is more effective than HT in reducing the CV of the neoplastic cells. Combined application of both PD and HT treatments was even more effective in reducing the CV of B16-F10 cells. At the highest light dose (2 J/cm(2)) and under magnetic field activation the CV was about half than PD applied alone. Therefore, the use of the photosensitizer-loaded magnetoliposome for combined photodynamic therapy (PDT) and magnetohyperthermia (MHT) application can be considered as a potential tool to treat malignant melanoma. (C) 2012 Elsevier B.V. All rights reserved.

Silicon(IV) phthalocyanine-loaded-nanoparticles for application in photodynamic process

The aim of this study was to evaluate the potential application of biodegradable nanoparticles containing a photosensitizer in photodynamic therapy. The poly (D,L lactic-co-glycolic acid) nanoparticles were studied by steady-state techniques, time-resolved fluorescence, and laser flash photolysis. The external morphology of the nanoparticles was established by scanning electron microscopy, and the biological activity was evaluated by in vitro cell culture by 3-(4,5 dimethylthiazol-2,5 biphenyl) tetrazolium bromide assay. The particles were spherical in shape exhibiting a 435 nm diameter with a low tendency to aggregate. The loading efficiency was 77%. The phthalocyanine-loaded-nanoparticles maintained their photophysical behavior after encapsulation. The cellular viability was determined, obtaining 70% of cellular death. All the performed physical-chemical, photophysical, and photobiological measurements indicated that the phthalocyanine-loaded-nanoparticles are a promising drug delivery system for photodynamic therapy and photoprocesses. (C) 2012 Laser Institute of America.

Study of CuO/CeO2 catalyst with for preferential CO oxidation reaction in hydrogen-rich feed (PROX-CO)

The CuO/CeO2 system was investigated as a catalyst for preferential CO oxidation reaction in hydrogen-rich feed (PROX-CO). The catalysts were prepared by deposition-precipitation (DEP) and co-precipitation (COP) methods and the catalytic performance reveals that the preparation method influences the properties of solids prepared, where a direct consequence is the difference in behavior of the catalysts in the PROX-CO reaction. A high specific area and a better dispersion of the metallic phase were obtained in the catalyst prepared by co-precipitation. The redox properties during the reaction were reported by measures of temperature programmed reduction (TPR), OSC measurements and X-ray absorption near edge structure (XANES-TPR) in situ showed the relationship between the preparation method, the physicochemical characteristics and redox properties in the PROX-CO reaction. By this means, the good dispersion of CuO and the best oxygen capacity are the response of the high performance of CuO/CeO2-COP catalysts for the PROX-CO reaction. Crown Copyright (c) 2012 Published by Elsevier B.V. All rights reserved.

Curcumin-loaded into PLGA nanoparticles

The incorporation of the curcumin into poly(lactic-co-glycolic)acid (PLGA) nanospheres by the nanoprecipitation technique, the characterization of the nanoparticles and the schistosomicidal activity of the curcumin-loaded into PLGA nanospheres were reported. The incorporation process occurred with high efficiency and the images of field-emission scanning electron microscopy (FESEM) revealed the production of spherically shaped particles. According to the dynamic light scattering measurements, the particles are nanometric and monodisperse. The curcumin-loaded PLGA nanoparticles (50 and 100 mu M) caused the death of all worms and a separation between 50% and 100% of Schistosoma mansoni couples at concentrations from 30 mu M. Moreover, the curcumin-loaded PLGA nanoparticles also decreased the motor activity and caused partial alterations in the tegument of adult worms. This study marks the first time that schistosomicidal activity has been reported for curcumin-loaded PLGA nanoparticles.