Span Values Research Articles

Fit accuracy of metal partial removable dental prosthesis frameworks fabricated by traditional or light curing modeling material technique: An in vitro study

ObjectiveThe aim of this study was to compare the fit accuracies of metal partial removable dental prosthesis (PRDP) frameworks fabricated by the traditional technique (TT) or the light-curing modeling material technique (LCMT).Materials and methodsA metal model of a Kennedy class III modification 1 mandibular dental arch with two edentulous spaces of different spans, short and long, was used for the study. Thirty identical working casts were used to produce 15 PRDP frameworks each by TT and by LCMT. Every framework was transferred to a metal master cast to measure the gap between the metal base of the framework and the crest of the alveolar ridge of the cast. Gaps were measured at three points on each side by a USB digital intraoral camera at ×16.5 magnification. Images were transferred to a graphics editing program. A single examiner performed all measurements. The two-tailed t-test was performed at the 5% significance level.ResultsThe mean gap value was significantly smaller in the LCMT group compared to the TT group. The mean value of the short edentulous span was significantly smaller than that of the long edentulous span in the LCMT group, whereas the opposite result was obtained in the TT group.ConclusionWithin the limitations of this study, it can be concluded that the fit of the LCMT-fabricated frameworks was better than the fit of the TT-fabricated frameworks. The framework fit can differ according to the span of the edentate ridge and the fabrication technique for the metal framework.

Formulation of nanoliposomal vitamin d3 for potential application in beverage fortification.

Vitamin D, a liposoluble vitamin has many benefits on health. Encapsulation of bioactives in lipid-based carrier systems like nanoliposomes preserves their native properties against oxidation over time along with providing its stable aqueous dispersion. In the current study, vitamin D3 nanoliposomes were prepared using thin-film hydration-sonication method and fully characterized by different instrumental techniques. According to FTIR and DSC results, no interaction was observed between encapsulated nutraceutical and liposome constituents. The particle size and size distribution (Span value) were calculated 82-90 nm and 0.70-0.85, respectively. TEM analysis showed nano sized globular and bilayer vesicles. In all formations, the encapsulation efficiency of vitamin D3 was calculated more than 93%. Addition of cholesterol to lecithin bilayer increased the negative zeta potential from -29 to -43mV. The results of this study concluded that the liposomal nanoparticles may be introduced as a suitable carrier for fortification of beverages with vitamin D3.

Formulation of gammaoryzanol-loaded nanoparticles for potential application in fortifying food products.

The field of nanoparticle delivery systems for nutrients and nutraceuticals with poor water solubility has attracted a great attention during the last decades. Ethyl cellulose (EC) based GO-loaded nanoparticles were prepared by solvent evaporation method. The effects of formulation parameters on nanoparticle size, encapsulation efficiency (EE%) and loading efficiency (LE%) were investigated. X-ray diffraction (XRD) and differential scanning calorimetry (DSC) techniques were used to investigate the crystalline behavior of GO and EC after the preparation of nanoparticles. Stability of the prepared nanoparticle was investigated during five weeks of storage. Particle sizes of all formulation were in the range of 70-100 nm with narrow size distribution. Increase in the time of sonication from 1 to 5 minutes decreased the particle size. However, the mean particle size was increased when the sonication time increased from 5 to 7 minutes. The results showed that in the same concentration of PVA, increasing the ratio of EC:GO led to an increase in the GO encapsulation efficiency and decrease in loading efficiency. During five weeks, the mean diameter and size distribution indexes (SPAN values) of nanoparticles did not show significant changes. DSC and XRD studies indicated that crystallinity of GO was decreased in nanoparticles. EC based nanoparticles are promising carriers for addition of GO as a water insoluble antioxidant to fortify liquid food products without any change in quality of products.

Manual tool grip span and grip force during flower cutting

To analyze the association between grip span of a manual flower cutting tool and maximum peak force exerted by each finger in the operating hand during apprehension. An experiment was conducted in which 11 women performed the stem cut of a flower. These women did not suffer from carpal tunnel syndrome. Grip span was calculated when they exerted the maximum peak force with each finger. The main finding of the study reveals that fingers exert the maximum peak force when the grip span values are the same for everyone. However, due to the shape of the tool commonly used in the Colombian flower industry (first order level), each finger reaches its maximum peak force at different times, bypassing the full capacity of each finger's grip force. These findings could be used to improve the mechanical advantage of manual cutting tools to reduce risk factors for carpal tunnel syndrome due to overexertion.

Centennial impacts of fragmentation on the canopy structure of tropical montane forest.

Fragmentation poses one of the greatest threats to tropical forests with short-term changes to the structure of forest canopies affecting microclimate, tree mortality, and growth. Yet the long-term effects of fragmentation are poorly understood because (1) most effects require many decades to materialize, but long-term studies are very rare, (2) the effects of edges on forest canopy structure as a function of fragment size are unknown, and (3) edge effects are often confounded by fragment shape. We quantified the long-term (centennial) effects of fragmentation on forest canopy structure using airborne light detection and ranging (LiDAR) of 1060 Hawaiian rain forest fragments ranging in size from 0.02 to 1000 ha, created more than 130 years ago by flowing lava. Along with distance from edge, we developed a metric, minimum span, to gain additional insight into edge effects on three measures of canopy structure: canopy height, height variation, and gap fraction. Fragment size was a strong determinant of the three structural variables. Larger fragments had greater average height, larger variation in height, and smaller gap fraction. Minimum span had a large effect on the depth and magnitude of edge effects for the three structural variables. Locations associated with high span values (those surrounded by more forest habitat) showed little effect of distance to fragment edge. In contrast, locations with low span values (those more exposed to edges) were severely limited in canopy height, showed lower height variation, and were associated with greater gap fraction values. The minimum span attribute allows for a more accurate characterization of edge as well as fragment-level effects, and when combined with high resolution imagery, can improve planning of protected areas for long-term ecological sustainability and biodiversity protection.

Study of dynamic graph ajustment operation in the optimization projects of hierarchical organizational structures

The research results of value adjustment influence on changes in the hierarchical graph structure are disclosed. The aim of the research is to establish regularities of the adjustment functions influence to the change in the hierarchical graph structure which characterizes changes in the span of control of the organizational structure. The structure of the hierarchical graph and organizational structures of span of control are experimentally studied. The original graph-fan is characterized by the maximal span of control. Using additive dynamic graph operation of the local subordination graph-fan is converted to different variations of the hierarchical graphs structures. The effect of the reduction of span of control of hierarchical organizational structure and the transition of the initial graph-fans to hierarchies of the higher level is considered. This is a result of specifying of arbitrary forms of the adjustment functions by assigning of ones and zeroes combinations to its values. The research results can be applied to the simulation modeling of organizational structures. The obtained regularities enable controlling the adjusting processes and values of spans of control of hierarchical organizational structures.

Redispersible liposomal-N-acetylcysteine powder for pulmonary administration: Development, in vitro characterization and antioxidant activity

Liposomal dry powders of N-acetylcysteine (SD-NAC-Lip) were developed for pulmonary administration. Liposomes were prepared by reverse phase evaporation and spray dried using lactose (10%, w/w) as drying adjuvant. The powders were characterized according to process yield, drug content, residual water content, particle size distribution, morphology and redispersion behavior. In vitro aerosol performance was evaluated using an eight-stage Andersen Cascade Impactor. Moreover, in vitro antioxidant activity was determined by measuring thiobarbituric acid reactive species (TBARS) present in the lungs of healthy Wistar rats after induction of oxidation by iron/EDTA. The spray-drying process had a high yield (71%±2), drug content (mg/g) according to the expected value, moisture content below 9%, geometric mean diameter under 3μm with span value lower than 1. Spherical particles were observed by scanning electron microscopy. Liposomal dry-powders were able to recover the nanometric size of the original dispersion after their redispersion in aqueous medium, as shown by laser diffraction and transmission electron microscopy. Furthermore, the powders presented aerodynamic diameter of about 7μm and respirable fraction above 30%, indicating suitable properties for pulmonary use. The encapsulation of N-acetylcysteine in liposomes was essential to maintain its in vitro antioxidant activity after the drying process. In addition, the powder containing the encapsulated drug had better in vitro antioxidant activity than the liquid and solid formulations containing the non-encapsulated drug, which makes it a good candidate for the treatment of pulmonary diseases associated with oxidative stress.

Survival and life span of Drosophila melanogaster in response to terahertz radiation

Life span control is realized by an interaction of many genetic factors with environment. Due to development of new modern technologies based on non-ionized terahertz radiation (0,1-10 THz) the investigation of this radiation influence on living organisms becomes actual. In our study terahertz radiation effects on survival and life span of Oregon R line of Drosophila meanogaster were multidirectional depending on the age of the insects. Terahertz effect on survival was negative or neutral in the early life and positive in the later life. In Drosophila response to terahertz radiation sex differences were manifested. Males were not very sensitive to terahertz radiation. Irradiated female survival was increased significantly in the second half of imago life. Irradiation of Drosophila not influenced significantly on average and maximal values of life span, but the gap between the values of average life span of males and females in this group of insects was increased. Mechanisms of terahertz radiation effects on survival and life span maybe associated with changes in cellular membrane, gene expression and signaling pathways, controlling these properties.

The Effects of CCRC on Cognition and Brain Activity in aMCI Patients: A Pilot Placebo Controlled BOLD fMRI Study

To investigate effects and functional mechanism of compound Congrongyizhi Capsule (CCRC), a Chinese medicine, on cognitive functions against amnestic mild cognitive impairment (aMCI) patients with functional magnetic resonance imaging (fMRI) based on n-back task. Forty-one aMCI participants from hospital and local communities in Beijing and randomly divided into treatment (16 patients with CCRC capsule treatment), placebo (12 patients with placebo capsules) and control group (13 patients with no treatment). The duration of intervention lasted for 3 months. Neuropsychological tests and fMRI were applied to assess cognitive ability and brain activation changes after three months treatment. Drug group (n=16) presented increased significance in the MMSE (P=0.008) and digit span (P<0.001) tests, while other scores of neuropsychological tests showed no statistical significance. fMRI results showed an increased brain negative activation in drug group during performing the n-back working-memory task in posterior cingulate (PCC), inferior frontal gyrus and lingual gyrus regions after 3 months; placebo and control group did not show the same effect. Meanwhile, there were negative correlations between left PCC activation levels and changed values of MMSE and digit span separately since increased negative activation was associated with better performance on the scores of MMSE and Digit Span tests. CCRC can increase negative activation degree of PCC under performing working memory tasks while this modulation are associated with better performance on the MMSE and Digit Span.

Preparation of uniform poly-caprolactone Microparticles by membrane emulsification/solvent diffusion process

Over the last decade, the use of polycaprolactone has attracted much interest in drug delivery compared to biodegradable polyesters derived from lactic and glycolic acids. The methodologies commonly used for the preparation of polycaprolactone microparticles are associated with many problems regarding the control of particle size and size distribution and particles morphology. Membrane emulsification/solvent diffusion processes offer great potentials in manufacturing particles. In this work, polycaprolactone microparticles with mean diameter of 20μm, spherical shape and smooth surface have been successfully produced using the emulsification/solvent diffusion method. The fluid-dynamic and chemical parameters have been optimized to produce uniform particles with a span value of 0.5. The effect of process parameters controlling the solvent diffusion on the shape and surface morphology has also been investigated. The use of microporous membranes allowed the simultaneous particle size and size distribution control during the emulsification step. Also, the solvent diffusion permitted easy control of the size and morphology of particles during the solidification of polymer within the droplets.

Emulsification using tubular metallic membranes

Tubular metallic membranes with pore diameters of 5 and 10 μm have been used in a cross-flow unit to prepare monodisperse oil-in-water emulsions (O/W) with span values as low as 0.67, significantly lower than for emulsions prepared with a rotor–stator homogenizer. The influence of typical operating parameters (continuous phase flow rate and transmembrane pressure) on droplet size distribution was studied. The smallest droplets were obtained at low transmembrane pressures and high continuous phase flow rates. The droplet production with tubular metallic membranes was higher than with other types of tubular membranes, such as SPG or ceramic. Experimental results were compared with those obtained in a stirred tank unit operating under similar conditions and using flat metallic membranes with the same pore diameter. Droplet size prediction models based on simple force balances were applied to compare theoretical and experimental droplet diameters. The droplet formation regime (dripping, jetting) was also studied for both types of membranes.

Computer modeling assisted design of monodisperse PLGA microspheres with controlled porosity affords zero order release of an encapsulated macromolecule for 3 months.

The aim of this study was the development of poly(D,L-lactide-co-glycolide) (PLGA) microspheres with controlled porosity, to obtain microspheres that afford continuous release of a macromolecular model compound (blue dextran). PLGA microspheres with a size of around 40μm and narrow size distribution (span value of 0.3) were prepared with a double emulsion membrane emulsification method. Gene expression programming (GEP) analysis was applied to design and formulate a batch of microspheres with controlled porosity that shows continuous release of blue dextran. Low porous microspheres with a high loading efficiency were formed at high polymer concentrations (30% w/w in the oil phase) and were characterized with a burst release <10% and a three-phasic release profile of blue dextran. Increasing porosity (10% w/w polymer concentrations), a sustained release of blue dextran was obtained albeit with up to 40% of burst release. The desired formulation, calculated by GEP, resulted in microspheres with 72% loading efficiency and intermediate porosity. Blue dextran was indeed released continuously in almost a zero order manner over a period of 3months after an initial small burst release of 9%. By fine-tuning the porosity, the release profile of PLGA microspheres for macromolecules can be predicted and changed from a three-phasic to a continuous release.

Premix membrane emulsification to produce oil-in-water emulsions stabilized with various interfacial structures of whey protein and carboxymethyl cellulose

Premix Membrane Emulsification (ME) with Shirasu Porous Glass membranes of 10 μm pore size enabled to produce oil-in-water (O/W) emulsions with different interfacial structures made of whey protein isolate (WPI) and carboxymethyl cellulose (CMC). Emulsions were stabilized by one interfacial layer, made of WPI (mono-layer emulsion) or 0.5 %wt WPI–0.25 %wt CMC complex (complex emulsion), or by two interfacial layers: one layer made of WPI and the second made of CMC (bi-layer emulsion) or WPI–CMC complex (sequential emulsion). Although the adsorption between the several layers was confirmed by Surface Plasmon Resonance (SPR), only O/W emulsions stabilized by one interfacial layer did not coalescence after homogenization. Mono-layer and complex emulsions were stable after emulsification with a 8.7 μm and 14.4 μm mean droplet size, respectively, although a significant amount of much smaller droplets contributed to increase droplet dispersion giving span values of 1.8 and 3.2 for mono-layer and complex emulsions, respectively.Regarding oxidation rate, TBARS in complex emulsions increased much faster than in mono-layer emulsions. Adsorption data at a hydrophobic interface and the electrical charge of the WPI–CMC complex suggested that it formed a thick (2.2 nm) but less dense (1.40 g cm−3) interface than WPI (2.59 g cm−3) with a negative charge able to attract any transition metal ion and promote lipid oxidation. Premix ME should be further optimized to obtain multi-layered interfaces with an external positive layer, e.g. made of WPI.

Emulsification Properties and Molecular Weight Distribution of Combretum Glutinosum Gum

The determination of weight average molecular weight (Mw) and radius of gyration (Rg) of Habeil gum was performed on a gel permeation chromatography-multi angle laser light scattering (GPC-MALLS) system. The results showed three main components of Combretum glutinosum gum designated arabinogalactan protein (AGP), arabinogalactan (AG) and glycoprotein (GP). The Mw of the freeze dried soluble part, freeze dried deacetylated gum, and freeze dried calcium-free gum were 2.06×106, 8.03×105, and 1.40×106 g /mol, respectively. The Mw of hydrophilic and hydrophobic components collected from soluble part gum are 3.16×106 and 6.08×105 g /mol, respectively, while the Mw of hydrophilic and hydrophobic components collected from deacetylated gum are 1.39×106 and 8.36×105 g /mol, respectively. Emulsification studies of the gum fractions showed lowest degree of span value than the starting material indicating good uniformity and increasing in adsorption of protein on oil droplet surface. The results of emulsion studies indicated that a blend of 50% w/w deacetylated Combretum glutinosum gum and 50% w/w Acacia Senegal produced better emulsification properties than the pure mother gum.

Nonlocal mass nanosensors based on vibrating monolayer graphene sheets

Single layer graphene sheets (SLGS) as a nanoscale label-free mass sensor are proposed. A mathematical framework according to nonlocal elasticity is considered. The nonlocal elasticity incorporates the small-scale effects or nonlocality in the analysis. Rectangular graphene resonators are assumed to be in cantilevered configuration. Closed-form nonlocal equations are derived for the frequency shift due to the added mass based on four types of different mass loadings. From the potential and kinetic energy of the mass loaded graphene sheets, generalised nondimensional calibration constants are proposed for an explicit relationship among the added mass, nonlocal parameter and the frequency shift. These equations based on nonlocal elasticity in turn are used for sensing the added mass (e.g. adenosine bio-fragment). Molecular mechanics simulation is used to validate the new nonlocal sensor equations. The optimal values of span of nonlocal parameter are used and compared with the molecular mechanics simulation results. The nonlocal approach generally predicts the frequency shift accurately compared to the local approach in most cases. Numerical results show the importance of considering the distributed nature of the added mass while using the nonlocal theory. The performance of the sensor is governed on the spatial distribution of the attached mass on the graphene sheet. Discussion on the numerical results illustrate that the sensitivity of graphene sensors is in the order of Gigahertz/zeptogram.

스트레스 리본 보도교의 설계절차

스트레스 리본 보도교는 특정한 새그을 갖는 지지 케이블에 교량 길이에 비하여 단면 두께가 아주 작은 Deck을 설치하고 프리스트레스를 도입함으로써 발생되는 긴장된 바닥판의 축력으로 외력의 대부분을 저항하는 구조물이다. 일반 구조물 설계와 달리 스트레스 리본 보도교의 설계는 Deck 단면의 가정 이외에도 지지 및 ...

Emulsification with microfiltration ceramic membranes: A different approach to droplet formation mechanism

Oil-in-water (O/W) emulsions were prepared by membrane emulsification (ME) in a large scale stirred tank with a submerged cell using flat membranes, and in a cross-flow tubular unit. Results obtained with flat and tubular membranes devices were compared. Common ceramic microfiltration (MF) membranes (ZrO2 supported on TiO2) were used in both cases. The main advantage of these membranes is their low cost compared to others frequently used in ME (SPG membranes), which implies a reduction up to 60%. The effect of operation parameters on droplet size distributions was studied to understand the droplet formation mechanism that takes place in both devices.Monodisperse O/W emulsions were obtained using flat membranes with a droplet-to-pore diameter ratio (Dd/Dp) in the range 2.1–2.9. Span values of 0.58, 0.66 and 0.81 corresponded to membrane pore diameters of 0.45, 0.80, and 1.4μm, respectively, being the active pores fraction in the range of 27–36%. The cross-flow tubular unit allowed for production of monodisperse O/W emulsions but with larger droplet sizes, having droplet-to-pore diameter ratios (Dd/Dp) in the range 3.9–4.7. It was observed a major influence of pore activation by dispersed phase pressure on droplet size distribution.Shear stress had little influence on the droplet size, with both flat and tubular membranes. This suggested that droplet formation mechanism was not shear stress-based. A spontaneous emulsification mechanism was proposed.

A practical optimization on salt/high-methoxyl pectin interaction to design a stable formulation for Doogh

Doogh is a traditional Iranian fermented drink. Response surface methodology-central composite design (RSM-CCD) was used to determine optimum formulation for the production of Doogh stabilized by high methoxyl pectin (HMP). The effects of HMP (0.28–0.42% wt) and salt (0.4–1.1% wt) concentrations on the stability, viscosity, volume-weighted (D43) and surface-weighted (D32) mean diameters and Span were investigated. Graphical response surface plots were applied to locate the optimum point. The optimum composition for stable Doogh production was found to contain (% wt) HMP 0.4 and salt 0.62. These optimum conditions yielded the stability of 96.34%, viscosity of 2.05mPas, D43 of 11.922μm, D32 of 0.966μm and Span value of 2.140. There was no significant difference between the physical, rheological and sensory attributes of Dooghs produced under optimum conditions and commercial samples.

Development and characterization of glutathione-conjugated albumin nanoparticles for improved brain delivery of hydrophilic fluorescent marker

The glutathione-conjugated bovine serum albumin (BSA) nanoparticles were constructed in the present exploration as a novel biodegradable carrier for brain-specific drug delivery with evaluation of its in vitro and in vivo delivery properties. BSA nanocarriers were activated and conjugated to the distal amine functions of the glutathione via carbodiimide chemistry using EDAC as a mediator. These nanoparticles were characterized for particle shape, average size, SPAN value, drug entrapment and in vitro drug release. Further, presence of glutathione on the surface of BSA nanoparticles was confirmed by Ellman’s assay, which has suggested that approximately 750 units of glutathione were conjugated per BSA nanoparticle. To evaluate the brain delivery properties of the glutathione-conjugated BSA nanoparticles fluorescein sodium was used as a model hydrophilic compound. Permeability and neuronal uptake properties of developed formulations were evaluated against the MDCK-MDR1 endothelial and neuro-glial cells, respectively. The permeability of glutathione-conjugated BSA nanoparticles across the monolayer of MDCK-MDR1 endothelial tight junction was shown significantly higher than that of unconjugated nanoparticles and fluorescein sodium solution. Similarly, glutathione-conjugated nanoparticles exhibited considerably higher uptake by neuro-glial cells which was inferred by high fluorescence intensity under microscope in comparison to unconjugated nanoparticles and fluorescein sodium solution. Following an intravenous administration, nearly three folds higher fluorescein sodium was carried to the rat brain by glutathione-conjugated nanoparticles as compared to unconjugated nanoparticles. The significant in vitro and in vivo results suggest that glutathione-conjugated BSA nanoparticles is a promising brain drug delivery system with low toxicity.

Efficient Parallel Search Algorithm for Determining Optimal R=1/2 Systematic Convolutional Self-Doubly Orthogonal Codes

A novel parallel and implicitly-exhaustive search algorithm for finding, in systematic form, rate R=1/2 optimal-span Convolutional Self-Doubly Orthogonal (CDO) codes and Simplified Convolutional Self-Doubly Orthogonal (S-CDO) codes is presented. In order to obtain high-performance low-latency codecs with these codes, it is important to minimize their constraint length (or "span") for a given J number of generator connections. The proposed exhaustive algorithm uses algorithmic enhancements over the best previously published searching techniques, yielding new and improved codes: we were able to obtain new optimal-span CDO/S-CDO codes (having order J∈{9} and J∈{10,11} respectively), as well as new codes having the shortest spans published to date for higher values of J (J∈{10,12,...,17} and J∈{12,...,20} for CDO and S-CDO codes respectively). The new codes and their error performance are provided. An analysis of the evolution of the CDO/S-CDO code error performance as J increases is presented, and the shortest CDO/S-CDO code span values for each given J are compared.