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PubMed2004

An archaeal histone-like protein as an efficient DNA carrier in gene transfer.

HPhA, a recombinant histone-like protein from Pyrococcus horikoshii OT3 strain, has compacting activity with DNA as previously reported. The extreme stability and DNA packaging activity of the HPhA make it a candidate as a DNA carrier. Here, the plasmid DNA-HPhA complexes were fully characterized by gel retardation assay and DNase resistance assay. It was further proved that HPhA has in vitro DNA transfection activity. HPhA-mediated transfection efficiency was dependent on the mass ratio of HPhA to DNA, the incubation time and the presence of calcium. A protocol for HPhA-mediated transfection in vitro was established to improve transfection efficiency. The optimal mass ratio of HPhA to DNA was 6:1, and the incubation time required for the DNA-HPhA complex to be in contact with the cell was 4 h. In addition, the presence of 2 mM CaCl2 in the cell culture medium was required for efficient transfection. Serum did not show inhibition of HPhA-mediated transfection. Most importantly, the cytotoxicity of HPhA is lower than that of commonly used cationic liposome-based gene delivery systems, and HPhA-mediated transfection in NIH 3T3, HEK 293, HL-7702, HepG2 and Cos 7 cell lines in vitro has a higher efficiency and reproducibility. These results demonstrate that the HPhA is a new, potentially widely applicable and highly efficient gene carrier.

Animals↗

PubMed2005

Factors affecting SFHR gene correction efficiency with single-stranded DNA fragment.

A 606-nt single-stranded (ss) DNA fragment, prepared by restriction enzyme digestion of ss phagemid DNA, improves the gene correction efficiency by 12-fold as compared with a PCR fragment, which is the conventional type of fragment used in the small fragment homologous replacement method [H. Tsuchiya, H. Harashima, H. Kamiya, Increased SFHR gene correction efficiency with sense single-stranded DNA, J. Gene Med. 7 (2005) 486-493]. To reveal the characteristic features of this gene correction with the ss DNA fragment, the effects on the gene correction in CHO-K1 cells of the chain length, 5'-phosphate, adenine methylation, and transcription were studied. Moreover, the possibility that the ss DNA fragment is integrated into the target DNA was examined with a radioactively labeled ss DNA fragment. The presence of methylated adenine, but not the 5'-phosphate, enhanced the gene correction efficiency, and the optimal length of the ss DNA fragment (approximately 600 nt) was determined. Transcription of the target gene did not affect the gene correction efficiency. In addition, the target DNA recovered from the transfected CHO-K1 cells was radioactive. The results obtained in this study indicate that length and adenine methylation were important factors affecting the gene correction efficiency, and that the ss DNA fragment was integrated into the double-stranded target DNA.

Adenine↗

PubMed2005

Application of a polyelectrolyte complex coacervation method to improve seeding efficiency of bone marrow stromal cells in a 3D culture system.

High seeding efficiency with homogenous distribution of limited cell sources such as bone marrow stromal cells (BMSCs) are of clinical relevance in scaffold-based tissue engineering. Therefore, considerable research efforts have been invested to ameliorate the seeding efficiency in 3D scaffolds. Preliminary data demonstrated that indeed BMSCs were viable and were able to proliferate in a model 3D scaffold, i.e. Cytomatrix scaffold. However, the eventual practical application of BMSCs in such 3D scaffolds is limited by the low seeding efficiency of the cells within the scaffold. Here, we demonstrated that the cell seeding efficiency of BMSCs in the Cytomatrix scaffold can be improved significantly (t-test, p<0.05) by means of macroencapsulating the scaffold via the complex coacervation of a methylated collagen and terpolymer. The thickness and density of the polyeletrolyte complex can be modulated by the contact time between the methylated collagen and terpolymer to balance between cell entrapment efficacy and mass transfer impedance imparted by the complex. Porcine BMSCs were macroencapsulated in Cytomatrix scaffolds using various polyelectrolyte contact time and cultured under both static and dynamic conditions. Throughout the range of contact time investigated, macroencapsulation did not affect the viability of the porcine BMSCs in dynamic culture. However, the viability of the cells under static cultures was compromised with longer polyelectrolyte contact time. Therefore, this proposed method of macroencapsulation enables customization to achieve enhanced seeding efficiency without mass transfer impedance for different culture configurations.

Adipocytes↗

PubMed2006

Improving the efficiency of evolutionary de novo peptide design: strategies for probing configuration and parameter settings.

Evolutionary molecular design based on genetic algorithms (GAs) has been demonstrated to be a flexible and efficient optimization approach with potential for locating global optima. Its efficacy and efficiency are largely dependent on the operations and control parameters of the GAs. Accordingly, we have explored new operations and probed good parameter setting through simulations. The findings have been evaluated in a helical peptide design according to "Parameter setting by analogy" strategy; highly helical peptides have been successfully obtained with a population of only 16 peptides and 5 iterative cycles. The results indicate that new operations such as multi-step crossover-mutation are able to improve the explorative efficiency and to reduce the sensitivity to crossover and mutation rates (CR-MR). The efficiency of the peptide design has been furthermore improved by setting the GAs at the good CR-MR setting determined through simulation. These results suggest that probing the operations and parameter settings through simulation in combination with "Parameter setting by analogy" strategy provides an effective framework for improving the efficiency of the approach. Consequently, we conclude that this framework will be useful for contributing to practical peptide design, and gaining a better understanding of evolutionary molecular design.

Algorithms↗

PubMed2006

High-efficient lentiviral vector-mediated gene transfer into primary human NK cells.

OBJECTIVE: The long-term transfection of genes into primary natural killer (NK) cells without disrupting normal cellular functions has been proven to be difficult with currently available gene-transfer methods. In this study, we establish a lentiviral vector-based technique for improved gene transfer into human NK cells in vitro and we report on high-efficient transduction of freshly isolated as well as cultured primary NK cells. METHODS: Freshly isolated or primary cultured human NK cells, as well as the human NK cell line YTS, were transduced with replication-incompetent human immunodeficiency virus (HIV)-based lentiviral vector bearing a GFP reporter gene or a gene of interest under the control of the elongation factor 1alpha (EF1alpha) promoter. Transduction efficiencies were monitored by flow cytometry. RESULTS: A long-term transgene expression was detected in up to 98% of YTS NK cells, whereas in freshly isolated or primary cultured NK cells exposed to interleukin (IL)-2 plus IL-12 upon infection, efficiency was in the range of 50% to 90%. Moreover, in freshly isolated quiescent NK cells a transfection efficiency of 18% to 20% was achieved without stimulation. Notably, no major phenotypic and functional modifications were observed in transduced cells with respect to control cells: the expression levels of activating receptors, CD69-antigen induction as well as cytotoxic function were unaffected. CONCLUSION: Results of our study demonstrate that NK cells can be efficiently transduced by lentiviral vectors.

Antigens, CD↗

PubMed2003

The auditory basis of language impairments: temporal processing versus processing efficiency hypotheses.

Claims have been made that language-impaired children have deficits processing rapidly presented or brief sensory information. These claims, known as the 'temporal processing hypothesis', are supported by demonstrations that language-impaired children have excess backward masking (BM). One explanation for these results is that BM is developmentally delayed in these children. However, little was known about how BM normally develops. Recently, we assessed BM in normally developing 6- and 8-year-old children and adults. Results showed that BM thresholds continue to improve over a comparatively protracted period (>10 years old). We also analysed reported deficits in BM in language-impaired and younger children, in terms of a model of temporal resolution. This analysis suggests that poor processing efficiency, rather than deficits in temporal resolution, can account for these results. This 'processing efficiency hypothesis' was recently tested in our laboratory. This experiment measured BM as a function of delays between the tone and the noise in children and adults. Results supported the processing efficiency hypothesis, and suggested that reduced processing efficiency alone could account for differences between adults and children. These findings provide a new perspective on the mechanisms underlying communication disorders, and imply that remediation strategies should be directed towards improving processing efficiency, not temporal resolution.

Auditory Threshold↗

PubMed2003

OQAFMA Querying agent for the Foundational Model of Anatomy: a prototype for providing flexible and efficient access to large semantic networks.

The development of large semantic networks, such as the UMLS, which are intended to support a variety of applications, requires a flexible and efficient query interface for the extraction of information. Using one of the source vocabularies of UMLS as a test bed, we have developed such a prototype query interface. We first identify common classes of queries needed by applications that access these semantic networks. Next, we survey StruQL, an existing query language that we adopted, which supports all of these classes of queries. We then describe the OQAFMA Querying Agent for the Foundational Model of Anatomy (OQAFMA), which provides an efficient implementation of a subset of StruQL by pre-computing a variety of indices. We describe how OQAFMA leverages database optimization by converting StruQL queries to SQL. We evaluate the flexibility and efficiency of our implementation using English queries written by anatomists. This evaluation verifies that OQAFMA provides flexible, efficient access to one such large semantic network, the Foundational Model of Anatomy, and suggests that OQAFMA could be an efficient query interface to other large biomedical knowledge bases, such as the Unified Medical Language System.

Abstracting and Indexing↗

PubMed2006

Dynamics of in vivo power output and efficiency of Nasonia asynchronous flight muscle.

By simultaneously measuring aerodynamic performance, wing kinematics, and metabolic activity, we have estimated the in vivo limits of mechanical power production and efficiency of the asynchronous flight muscle (IFM) in three species of ectoparasitoid wasps genus Nasonia (N. giraulti, N. longicornis, and N. vitripennis). The 0.6 mg animals were flown under tethered flight conditions in a flight simulator that allowed modulation of power production by employing an open-loop visual stimulation technique. At maximum locomotor capacity, flight muscles of Nasonia are capable to sustain 72.2 +/- 18.3 W kg(-1) muscle mechanical power at a chemo-mechanical conversion efficiency of approximately 9.8 +/- 0.9%. Within the working range of the locomotor system, profile power requirement for flight dominates induced power requirement suggesting that the cost to overcome wing drag places the primary limit on overall flight performance. Since inertial power is only approximately 25% of the sum of induced and profile power requirements, Nasonia spp. may not benefit from elastic energy storage during wing deceleration phases. A comparison between wing size-polymorphic males revealed that wing size reduction is accompanied by a decrease in total flight muscle volume, muscle mass-specific mechanical power production, and total flight efficiency. In animals with small wings maximum total flight efficiency is below 0.5%. The aerodynamic and power estimates reported here for Nasonia are comparable to values reported previously for the fruit fly Drosophila flying under similar experimental conditions, while muscle efficiency of the tiny wasp is more at the lower end of values published for various other insects.

Animals↗

PubMed2006

Regulation of transduction efficiency by pegylation of baculovirus vector in vitro and in vivo.

In this study, poly(ethylene glycol) (PEG) was coupled to baculovirus to regulate transduction efficiency of baculovirus in vitro and in vivo. The degree of pegylation in virions was measured by the loss of free amines via a fluorescamine-based assay. The efficiency of green fluorescent protein (GFP) expression was used to monitor transduction efficiency. As the results, the transduction efficiency in pegylated baculovirus was decreased with an increase of pegylation in baculovirus in vitro and in vivo. Interestingly, the transduction efficiency of the pegylated baculovirus for the lung and brain was increased compared with baculovirus itself possibly owing to increased stability of baculovirus by pegylation.

Animals↗

PubMed2006

PEI-alginate nanocomposites as efficient in vitro gene transfection agents.

The positive charge on PEI was partially shielded by forming ionic nanocomposites with a polysaccharide, alginic acid, in aqueous solution, bypassing tedious chemical synthesis. The content of alginic acid was varied systematically to obtain a series of nanocomposites. The nanocomposites were first characterized by assessing the surface charge (zeta potential), size (DLS) and morphology (AFM) followed by evaluation for their DNA interaction ability, cytotoxicity and transfection efficiency on various cell lines. The transfection efficiency of PEI-alginate (6.26%) nanocomposites improved dramatically (2-16-fold over native PEI) in all the cell lines studied. However, a decrease in transfection efficiency was observed on deviating from this optimal concentration of alginic acid in nanocomposites. Cytotoxicity of PEI-alginate/DNA complexes was nearly abolished on increasing the concentration of alginic acid in nanocomposites. PEI-alginate (6.26%) nanocomposites also delivered SiRNAs efficiently into mammalian cells, resulting in 80% suppression of GFP expression. The cellular uptake and endosomal escape of PEI-alginate nanocomposites and PEI were found to follow a similar route when transfection was carried out in presence of chloroquine, bafilomycin A1, cytochalasin B and methyl-beta-cyclodextrin. The results demonstrate a versatile vector that can be used for efficient cytoplasmic delivery of a broad range of nucleic acids.

Alginates↗

PubMed2005

Molar extinction coefficients and the photon absorption efficiency of dental photoinitiators and light curing units.

OBJECTIVES: The light absorption of dental photoinitiators should correlate with the spectral emission profiles of dental light curing units compared on an equivalent basis. Spectral data of dental photoinitiators and light curing units can be used to define the photon absorption efficiency (PAE) obtained by integrating the product of the absorption and emission spectra in terms of photons. This parameter can be used to identify the best performance for photochemical process with specific photoinitiators. METHODS: The efficiency of two LED and one QTH lamps were tested comparing their performances with the photoinitiators camphorquinone (CQ); phenylpropanedione (PPD); monoacylphosphine oxide (Lucirin TPO); and bisacylphosphine oxide (Irgacure 819). Absorption and emission spectra of the photoinitiators and the LED (Ultrablue I and Ultrablue IS) and QTH (Optilux 401) LCUs were determined in the 360-550nm range. RESULTS: CQ exhibited an absorption centered in the blue region and, although the maxima of PPD, MAPO, and BAPO were in the UV-A region, their absorption extended to the visible region. Power output maxima of the LCUs were at 467 (Ultrablue I), 454 (Ultrablue IS) and 493nm (Optilux 401), and the total power densities were 170+/-1, 470+/-4 and 444+/-4mW/cm(2), respectively. SIGNIFICANCE: The use of the PAE allows a prediction of the most efficient photoinitiator/LCU systems. For similar photoinitiator concentrations, Lucirin and CQ are most efficiently photoinitiated by the QTH unit, whereas the high-power LED device is more efficient for Irgacure. PPD is photoactivated similarly by both LCUs.

Acrylic Resins↗

PubMed2005

Eco-efficiency in extended supply chains: a case study of furniture production.

This paper presents a methodology about how eco-efficiency in extended supply chains (ESCs) can be understood and measured. The extended supply chain includes all processes in the life cycle of a product and the eco-efficiency is measured as the relative environmental and value performance in one ESC compared to other ESCs. The paper is based on a case study of furniture production in Norway. Nine different environmental performance indicators are identified. These are based on suggestions from the World Business Council for Sustainable Development and additional indicators that are shown to have significant impacts in the life cycle of the products. Value performance is measured as inverse life cycle costs. The eco-efficiency for six different chair models is calculated and the relative values are shown graphically in XY-diagrams. This provides information about the relative performance of the products, which is valuable in green procurement processes. The same method is also used for analysing changes in eco-efficiency when possible alterations in the ESC are introduced. Here, it is shown that a small and realistic change of end-of-life treatment significantly changes the eco-efficiency of a product.

Ecology↗

PubMed2026

Integrated photoelectrocatalytic reduction and oxidation processes to achieve efficient degradation of fluoxetine in pharmaceutical wastewater.

Fluorinated organic compounds have been frequently detected in aquatic environments, with the widespread use of fluorinated drugs. The existing processes of urban sewage treatment plants are difficult to completely remove these pollutants containing the persistent C-F bonds. In this work, an integrated system of UV-activated sulfite and UV-assisted electrochemical oxidation was innovatively constructed for efficient degradation of fluoxetine. For the UV-activated sulfite unit system, when the sulfite dosage was 0.5 mmol/L and the initial pH was about 10, the defluorination efficiency of 5 mg/L fluoxetine wastewater under nitrogen atmosphere was about 98 %. Subsequently, the UV-assisted electrochemical oxidation unit system was employed to treat the reduced wastewater mentioned above. When the sodium chloride dosage was 25 mmol/L, the initial pH was about 5, and the current density was 30 mA/cm2, the total organic carbon (TOC) removal of the wastewater arrived at 65 %. Active species capture experiments and ESR tests confirmed that hydrated electrons, hydroxyl, and chlorine radicals were the main components for the efficient degradation of fluoxetine. According to the analysis of Fukui function and HPLC-MS, the degradation pathway of pollutants was proposed including defluorination and mineralization. Meanwhile, the toxicity of intermediates was predicted using the ECOSAR program. In addition, the verification test of actual wastewater treatment indicated that the defluorination and TOC removal efficiency of fluorouracil by the integrated system were similar to those for fluoxetine. This work provided a new approach for the efficient degradation of fluorinated organic pollutants in pharmaceutical wastewater.

Fluoxetine↗

PubMed2005

The effect of ash and filter media characteristics on particle filtration efficiency in fluidized bed.

The phenomenon of filtering particles by a fluidized bed is complex and the parameters that affect the control efficiency of filtration have not yet been clarified. The major objective of the study focuses on the effect of characteristics of ash and filter media on filtration efficiency in a fluidized bed. The performance of the fluidized bed for removal of particles in flue gas at various fluidized operating conditions, and then the mechanisms of collecting particles were studied. The evaluated parameters included (1) various ashes (coal ash and incinerator ash); (2) bed material size; (3) operating gas velocity; and (4) bed temperature. The results indicate that the removal efficiency of coal ash increases initially with gas velocity, then decreases gradually as velocity exceeds some specific value. Furthermore, the removal of coal ash enhance with silica sand size decreasing. When the fluidized bed is operated at high temperature, diffusion is a more important mechanism than at room temperature especially for small particles. Although the inertial impaction is the main collection mechanism, the "bounce off" effect when the particles collide with the bed material could reduce the removal efficiency significantly. Because of layer inversion in fluidized bed, the removal efficiency of incinerator ash is decreased with increasing of gas velocity.

Carbon↗

PubMed2006

Development of a double-layered ceramic filter for aerosol filtration at high-temperatures: the filter collection efficiency.

The performance of double-layered ceramic filters for aerosol filtration at high temperatures was evaluated in this work. The filtering structure was composed of two layers: a thin granular membrane deposited on a reticulate ceramic support of high porosity. The goal was to minimize the high pressure drop inherent of granular structures, without decreasing their high collection efficiency for small particles. The reticulate support was developed using the technique of ceramic replication of polyurethane foam substrates of 45 and 75 pores per inch (ppi). The filtering membrane was prepared by depositing a thin layer of granular alumina-clay paste on one face of the support. Filters had their permeability and fractional collection efficiency analyzed for filtration of an airborne suspension of phosphatic rock in temperatures ranging from ambient to 700 degrees C. Results revealed that collection efficiency decreased with gas temperature and was enhanced with filtration time. Also, the support layer influenced the collection efficiency: the 75 ppi support was more effective than the 45 ppi. Particle collection efficiency dropped considerably for particles below 2 microm in diameter. The maximum collection occurred for particle diameters of approximately 3 microm, and decreased again for diameters between 4 and 8 microm. Such trend was successfully represented by the proposed correlation, which is based on the classical mechanisms acting on particle collection. Inertial impaction seems to be the predominant collection mechanism, with particle bouncing/re-entrainment acting as detachment mechanisms.

Aerosols↗

PubMed2005

Efficient gene transfer into normal human B lymphocytes with the chimeric adenoviral vector Ad5/F35.

The failure to efficiently introduce genes into normal cells such as human B lymphocytes limits the characterization of their function on cellular growth, differentiation and survival. Recent studies have shown that a new adenoviral vector Ad5/F35 can efficiently transduce human haematopoietic CD34+ progenitor cells. In this study, we compared the gene transfer efficiencies of the Ad5/F35 vector to that of the parental vector Ad5 in human B lymphocytes. Peripheral blood B cells obtained from healthy individuals were cultured in vitro using CD40-CD154 system. Normal B lymphocytes were infected with replication-defectives Ad5 and Ad5/F35, both containing the GFP reporter gene, and transduction efficiencies were monitored by flow cytometry. Ad5 was highly ineffective, infecting only about 5% of human B lymphocytes. In contrast, Ad5/F35 transduced up to 60% of human B lymphocytes and GFP expression could be detected for up to 5 days post infection. Importantly, physiology of B lymphocytes such as proliferation, viability and antibodies secretion were unaffected following Ad5/F35 transduction. Finally, we observed that memory B lymphocytes were more susceptible to Ad5/F35 infection than naïve B lymphocytes. Thus, our results demonstrate that the adenoviral vector Ad5/F35 is an efficient tool for the functional characterization of genes in B lymphopoiesis.

Adenoviruses, Human↗

PubMed2006

Subcellular localization pattern of protoporphyrin IX is an important determinant for its photodynamic efficiency of human carcinoma and normal cell lines.

Photodynamic therapy (PDT) is a combination of light with a lesion-localizing photosensitizer or its precursor to destroy the lesion tissue. PDT has recently become an established modality for several malignant and non-malignant conditions, but it can be further improved through a better understanding of the determinants affecting its therapeutic efficiency. In the present investigation, protoporphyrin IX (PpIX), an efficient photosensitizer either endogenously induced by 5-aminolevulinic acid (ALA) or exogenously administered, was used to correlate its subcellular localization pattern with photodynamic efficiency of human oesophageal carcinoma (KYSE-450, KYSE-70) and normal (Het-1A) cell lines. By means of fluorescence microscopy ALA-induced PpIX was initially localized in the mitochondria, whereas exogenous PpIX was mainly distributed in cell membranes. At a similar amount of cellular PpIX PDT with ALA was significantly more efficient than photodynamic treatment with exogenous PpIX at killing all the 3 cell lines. Measurements of mitochondrial membrane potential and intracellular ATP content, and electron microscopy showed that the mitochondria were initially targeted by ALA-PDT, consistent with intracellular localization pattern of ALA-induced endogenous PpIX. This indicates that subcellular localization pattern of PpIX is an important determinant for its PDT efficiency in the 3 cell lines. Our finding suggests that future new photosensitizers with mitochondrially localizing properties may be designed for effective PDT.

Adenosine Triphosphate↗

PubMed2005

Acute decrease of left ventricular mechanical dyssynchrony and improvement of contractile state and energy efficiency after left ventricular restoration.

OBJECTIVE: Surgical left ventricular restoration by means of endoventricular patch aneurysmectomy in patients with postinfarction aneurysm should result in acute improved left ventricular performance by decreasing mechanical dyssynchrony and increasing energy efficiency. METHODS: Nine patients with left ventricular postinfarction aneurysm were studied intraoperatively before and after ventricular restoration with a conductance volume catheter to analyze pressure-volume relationships, energy efficiency, and mechanical dyssynchrony. The end-systolic elastance was used as a load-independent index of contractile state. Left ventricular energy efficiency was calculated from stroke work and total pressure-volume area. Segmental volume changes perpendicular to the long axis were used to calculate mechanical dyssynchrony. Statistical analysis was performed with the paired t test and least-squares linear regression. RESULTS: Endoventricular patch aneurysmectomy reduced end-diastolic volume by 37% (P < .001), with unchanged stroke volume. Systolic function improved, as derived from increased +dP/dt(max), by 42% (P < .03), peak ejection rate by 28% (P < .02), and ejection fraction by 16% (P < .0002). Early diastolic function improved, as shown by reduction of -dP/dt(max) by 34% (P < .006) and shortened tau by 30% (P < .001). Left ventricular end-systolic elastance increased from 1.2 +/- 0.6 to 2.2 +/- 1 mm Hg/mL (P < .001). Left ventricular energy efficiency increased by 36% (P < .002). Left ventricular mechanical dyssynchrony decreased during systole by 33% (P < .001) and during diastole by 20% (P < .005). CONCLUSIONS: Left ventricular restoration induced acute improvements in contractile state, energy efficiency, and relaxation, together with a decrease in left ventricular mechanical dyssynchrony.

Aged↗