Large Volumes Of Liquid Research Articles

Administration of olive oil followed by a low volume of polyethylene glycol-electrolyte lavage solution improves patient satisfaction with right-side colonic cleansing over administration of the conventional volume of polyethylene glycol-electrolyte lavage solution for colonoscopy preparation

Proper bowel cleansing before colonoscopy is essential for satisfactory evaluation of the colon. The required consumption of a large volume of salty-tasting liquid, 4 L of polyethylene glycol-electrolyte lavage solution (PEG-ELS), is the primary limitation to achieving this goal. To achieve better patient satisfaction with efficient bowel cleansing, we compared the effects of the conventional volume (4 L) of PEG-ELS with those of a low volume (2 L) in combination with pretreatment using different laxatives, such as magnesium hydroxide (milk of magnesia) and olive oil. Randomized, controlled study. A single research hospital. Patients undergoing elective colonoscopy. A total of 120 patients were randomized to 1 of 3 different preparation regimens: 39 patients were prepared with a conventional volume (4 L) of PEG-ELS (Preparation [Prep] 1), and the remaining patients were prepared with a lower volume (2 L) of PEG-ELS and pretreatment with a laxative, either 15 g of magnesium hydroxide (40 patients, Prep 2) or 60 mL of olive oil (41 patients, Prep 3) 3 hours before PEG-ELS administration. The primary outcome was the efficacy of colonic cleansing on the left and right sides. Secondary outcomes were patient satisfaction and side effects. The olive oil regimen (Prep 3) resulted in significantly more adequate bowel cleansing of the right colon than administration of the conventional volume of PEG-ELS (Prep 1) and the magnesium hydroxide (Prep 2) regimen (97.6% vs 74.5% and 72.5%, respectively, P = .007). However, this difference was not observed in the left colon (91.5%, 85.5%, and 91.8% for Preps 1, 2, and 3, respectively, P = .776). When asked, 38 patients (95%) taking Prep 2, 35 patients (85.3%) taking Prep 3, and only 11 patients (28.2%) taking Prep 1 preferred the same preparation regimen if they required a future colonoscopy (P =.006), based on ease of use and taste. The side effects were comparable in each group. The limitations of this study include the relatively small sample size, the single-center study design, and the use of a nonvalidated symptom scoring system. Pretreatment with olive oil before administration of a low volume of PEG-ELS enhances both patient satisfaction and the quality of right-side colonic cleansing over the administration of the conventional volume of PEG-ELS for colonoscopy preparation. Although the magnesium hydroxide regimen (Prep 2) was the preferred regimen in this study, its colonic cleansing effectiveness was not as great as those of the other regimens. Based on our results, the olive oil regimen is recommended, especially for patients who are not able to consume large volumes of liquids, such as the elderly, and those who are suspected of having subtle right-side colonic lesions.

10 POSTCERVICAL INSEMINATION OF SOWS WITH REDUCED SPERM NUMBERS IN FIELD CONDITIONS

In the current procedures for AI in pigs, billions of spermatozoa are used (2.5–4.0 × 109 spermatozoa per insemination) in a large volume of liquid (70–100 mL), which is deposited in the cervix at the moment of AI. Approximately 90% of the spermatozoa inseminated cannot be recovered from the uterus at 2 h after AI (Viring S et al. 1980 Acta Vet. Scand. 21, 145–149). Several technical methods are used in the pig production industry for semen application using AI. To reduce the number of spermatozoa, several methods have been developed. The present study was performed to evaluate the reproductive effects under field conditions of postcervical AI (post-CAI) in southeast Spain with multiparous sows. In total, 509 sows were inseminated and divided in 3 groups: sows in the first group were inseminated using cervical AI (CAI, control group) with 3 × 109 spermatozoa in 80 mL of extender (group 1, n = 168); sows in the second group were inseminated by post-CAI using 1.5 × 109 spermatozoa in 40 mL of extender (group 2, n = 175); and sows in the third group were inseminated by post-CAI but using 1 × 109 spermatozoa in 26 mL of extender (group 3, n = 166). The catheter used for post-CAI consisted of a conventional AI catheter with an additional inner catheter that could extend past the catheter tip (Soft & Quick®, Import-Vet, Barcelona, Spain). Day 28 of pregnancy rates, farrowing rates, total pigs born, total live piglets, and stillborns were evaluated. Data were analyzed by ANOVA. Pregnancy and farrowing rates after post-CAI with 1.5 × 109 or 1 × 109 spermatozoa did not differ from those of the control group (group 1: 87.50%; group 2: 88.57%; group 3: 86.14%; P = 0.367). The number of spermatozoa inseminated did not significantly affect the number of live (12.27 ± 4.99; 12.18 ± 5.20; 12.64 ± 5.31; P = 0.946) or stillborn pigs (1.60 ± 1.79; 1.80 ± 2.27; 1.78 ± 1.84; P = 0.386) or the total number of piglets born (13.87 ± 5.39; 14.02 ± 5.75; 14.42 ± 5.65; P = 0.865). The present study shows that post-CAI with a low number of sperm cells does not negatively influence the reproductive parameters of multiparous sows compared with conventional AI. In conclusion, post-CAI in sows is simple, effective, and safe, and allows the sperm dose to be reduced to one billion spermatozoa.

Complications of permanent dual‑chamber pacing such as late purulent pacemaker pocket infection with broken and looped atrial lead, complicated by pulmonary embolism after transvenous lead removal: a case report

We present a complication of the infected pacing system extraction by lobular pneumonia in a 73-year-old female patient. The pacing system involved DDD pacemaker, atrial and ventricular endocardial leads implanted 12 year beforehand. The defect of the atrial lead emerged during the pacemaker replacement 4 years ago. The diagnosis of the injury cause and its reparation were not undertaken at that time. An interruption of the atrial lead which resulted in the formation of a loop inside the cardiac chamber was found when purulant pacemaker pocket infection had been diagnosed. The patient was referred for the pacing system extraction after preoperative specific antibiotic treatment. After a long-lasting, difficult, two-step leads extraction procedure, pneumonia developed. An echocardiogram revealed enlargement of the right atrium and ventricle, with elevated pulmonary artery pressure up to 40 mmHg. An atypical chest X-ray with the presence of a large pleural liquid volume led to the work-up of hemorrhagic complications and postponed the antithrombotic therapy. With the delay of 1.5 month the pulmonary scintigraphy showed features of pulmonary embolism. The embolism was most likely caused by a vegetation mobilized from the endocardial lead and/or endocardium during the extraction maneuvers. Before the surgery, the vegetations attached to the leads or to the endocardium had not been visualized. Anticoagulant therapy with antivitamins K was successful, which resulted in the pulmonary pressure normalization. The patient has remained in a good condition for the next 3 months of follow-up.

Sequencing

Sequencing

A model of flocculation

The phenomenon of flocculation in liquid suspensions has a variety of applications, including mineral processing, treatment of industrial effluents, and municipal sewage sludge purification. Obtaining metals from ores would not be possible without the slurry processing route. Flocculants play here a double role: limiting environmental contamination and also slowing down depletion of raw materials — including potable, industrial and agricultural water. Development of better flocculants requires improved understanding of the mechanism of their action. We propose a model of flocculation based on the assumption that effective flocculants pervade large volumes of liquids in the suspensions. Since many flocculants are polymers, good flocculants according to the model should have large radii of gyration R G. We therefore assume a connection between R G and settling velocities y of particles out of suspension. Four different types of aqueous suspensions are studied, containing in turn silica, coal, Mn ore and Fe ore. A unique relationship is demonstrated between R G and y for several polymeric flocculants in each type of slurry. For each suspension type the corresponding equation has the form y = aR G b , where the two parameters characterize the suspended particles and the liquid medium. While polysaccharides from natural sources are used as flocculants, we show how their cationization enhances the flocculation efficiency in all media we have studied. Large effects are achieved for the flocculating agent concentrations in the range of 6–9 ppm.

Thermal Explosion in a Flammable Gas Containing Fuel Droplets: Asymptotic Analysis

The problem of thermal explosion in a flammable gas mixture with addition of volatile fuel droplets is studied based on the asymptotic method of integral manifolds. The model for the radiative heating of droplets takes into account the semitransparency of droplets. A simplified model for droplet heat-up is used. The results of the analysis are applied to the modelling of thermal explosion in diesel engines. Two distinct dynamical situations have been considered, depending on the initial droplet concentration. These are ‘far zone’ (small initial liquid volume fraction and small droplet radii) and ‘near zone’ (large initial liquid volume fraction and large droplet radii). The conditions of the first zone are typical for the areas in the combustion chamber which are far from the fuel injectors, while the conditions of the second zone are typical for the areas in the combustion chamber which are relatively close to the fuel injectors. It has been pointed out that small droplets’ heating and evaporation time in the far zone is smaller than the chemical ignition delay of the fuel vapor/air mixture. The total ignition delay decreases with increasing initial gas temperature. In the near zone for large droplets, the process starts with the initial gas cooling and slight heating of droplets. This is followed by a relatively slow heating of gas due to the chemical reaction, and further droplet heating. The total ignition delay in the near zone is larger than in the far zone. It is expected that before thermal explosion in the near zone takes place, the droplets break up and are removed from this zone. In optically thick gas effects of thermal radiation are negligible for small droplets but are noticeable for large droplets.

Effect of particle size ratio and particle clustering on sintering and stiffness of aluminium matrix composite

A metal matrix composite with a matrix composition of Al–3·8Cu–1Mg–0·75Si–0·5Sn was fabricated by sintering a particulate ceramic reinforcement with elemental metal powders. The sintering characteristics were examined as a function of reinforcement volume fraction, particle size and particle size ratio. At high volume fractions of reinforcement, densification ceased completely and the compacts expanded during sintering. Coarse reinforcement particles, not large particle size ratios, maximised the sintering response. Clustering of the ceramic was studied using Dirichelet tessellations of sintered microstructures. While clustering is evident in the sintered microstructures, it does not correlate to sintered density through the particle size ratio because the ceramic particles appear to rearrange in the presence of a large volume of sintering liquid. The effect of particle size is not due to clustering but maybe due to ceramic particle surface area.

Influence of Fan Nozzle Tip Orifice Wear on Spray Pattern

Vezetéknév

Competitive Destabilization/Stabilization of β‐Lactoglobulin Foam by PEO‐PPO‐PEO Polymeric Surfactants

The effect on β‐lactoglobulin foamability and foam stability of the poly(ethylene oxide)‐poly(propylene oxide) block copolymers F127 (PEO99‐PPO65‐PEO99), molecular weight 12500 g/mol, and P85 (PEO26‐PPO39‐PEO26), molecular weight 4600 g/mol, has been investigated at constant protein concentration, 10 µM (0.2 mg/L), and varying block copolymer concentrations, ranging from 0.02 to 1600 µM. Foam was generated by means of air sparging and the foam volume and liquid volume of the foam were measured for one hour. It was found that foam stabilized by F127 or P85 in the concentration range 20–1600 µM contained a larger liquid volume initially than pure β‐lactoglobulin foam. Furthermore, β‐lactoglobulin foamability was only marginally affected by the presence of F127, while it was reduced in an interval of low P85 concentrations. The protein foam stability was retained in the presence of the larger polymer F127, whereas P85 largely reduced the stability, indicating that the size of the polymeric surfactant is important. The results are discussed in relation to surface rheological properties and forces acting across foam films. Steric repulsion generated between the surfaces of foam films is suggested to be the main stabilizing factor in dry foam containing F127. The instability of the mixed β‐lactoglobulin/P85 system is suggested to be caused by two effects. First, there are incompatible stabilization mechanisms of block copolymer and protein, as supported by previous surface rheological data. Second, there is a reduced importance of long‐range steric repulsion when P85 is added, compared to the case where F127 and β‐lactoglobulin are mixed.

Online headspace chromatographic method for measuring VFA in biogas reactor

A headspace chromatographic method has been applied to measure volatile fatty acids in anaerobic digesters using gas phase extraction at pH less than 2 and temperature higher than 65 degrees C. The concentration of volatile fatty acids in liquid and gas phase can be correlated in the form of Henry's coefficient. Analysis of different factors in the batch indicated that pH, temperature, and salt addition had a strong impact on apparent solubility, while liquid/gas volume ratio and organic acid concentration had little impact. Larger liquid volume had a positive impact on extraction efficiency, while increased gas headspace had a negative impact, indicating that the system was total mass-limited. The best conditions were at pH < 2.0, and temperatures above 75 degrees C. The advantage of an automated gas-extraction system for organic acid analysis, compared to an automated liquid system is that it contains no filter element, which is 4 susceptible to fouling in manure samples or samples with high solid content. An automated system which included a valerate pulse to the parent reactor was implemented, and operated for a short period.

Reduced gravity evaluation of potential spaceflight‐compatible flow cytometer technology

The presence of a spaceflight-compatible flow cytometer onboard the International Space Station would be extremely beneficial for in-flight medicine and reduced gravity research. In the past, commercially available flow cytometers were not suitable for use during spaceflight due to their size, weight, power, and sheath fluid requirements. Recent advances in cytometer technology have enabled features that now make a spaceflight-compatible cytometer possible. We evaluated a small, robust novel cytometer with design features that minimize or eliminate many incompatibilities with spaceflight. This cytometer is highly miniaturized and lightweight, does not require sheath fluid, and uses a low-energy diode laser. The ability to achieve laminar particle flow without sheath fluid is important because an instrument using large liquid volumes and producing an equivalent amount of hazardous liquid waste would not meet spaceflight constraints. For this study the cytometer was modified so that stained liquid cell samples could be delivered during reduced gravity. The cytometer was then evaluated onboard the NASA KC-135 reduced gravity research aircraft. The KC-135 uses a parabolic flight path to generate essentially zero gravity conditions for 30-s increments. Typically 40 parabolas are flown per mission, resulting in approximately 20 min of reduced gravity during which research may be performed. During this evaluation, bead-based cytometer precision, photomultiplier tube linearity, and leukocyte immunophenotype analysis were performed during reduced gravity. The flight data were then compared with ground-based control data and data generated using a reference cytometer (Beckman-Coulter XL). This novel cytometer functioned well during reduced gravity and produced data comparable to those of ground-based controls with only minor caveats. The reduced gravity cell immunophenotype data were indistinguishable from ground control data and reference cytometric data. Bead-based instrument precision (coefficient of variation) was slightly increased during reduced gravity operation, but not to a degree that would affect most common flow cytometric applications. The ability of the instrument to collect absolute cell counts was validated. This study represents the first generation of real-time flow cytometry data during zero gravity. With modifications, the evaluated cytometer technology could be the basis from which an operational spaceflight-compatible flow cytometer is developed.

Organogels in drug delivery

In the last decade, interest in physical organogels has grown rapidly with the discovery and synthesis of a very large number of diverse molecules, which can gel organic solvents at low concentrations. The gelator molecules immobilise large volumes of liquid following their self-assembly into a variety of aggregates such as rods, tubules, fibres and platelets. The many interesting properties of these gels, such as their thermoreversibility, have led to much excitement over their industrial applications. However, only a few organogels are currently being studied as drug/vaccine delivery vehicles as most of the existing organogels are composed of pharmaceutically unacceptable organic liquids and/or unacceptable/untested gelators. In this paper a brief overview of organogels is presented, followed by a more in-depth review of the gels that have been investigated for drug and/or vaccine delivery. These include microemulsion-based gels and lecithin gels (studied for transdermal delivery), sorbitan monostearate organogels and amphiphilogels (studied as vaccine adjuvants and for oral and transdermal drug delivery, respectively), gels composed of alanine derivatives (investigated as in situ forming gels) and Eudragit organogels (studied as a matrix for suppositories). Finally, pluronic lecithin organogels, descendents of lecithin gels but which are not really organogels, are briefly discussed for their interesting history, their root and the wide interest in these systems.

Electric Field Induced Instability and Pattern Formation in Thin Liquid Films

Electrostatic field induced instability, morphology, and patterning of a thin liquid film confined between two electrodes with an air gap are studied on the basis of nonlinear 3D simulations, both for spatially homogeneous and heterogeneous fields. In addition to the spinodal flow resulting from the variation of field because of local thickness changes, a heterogeneous imposed field also moves the liquid from the regions of low field to high field, thus allowing a more precise control of pattern. Hexagonal packing of liquid columns is observed for a spatially homogeneous electric field, which is in accord with the e-field experiments on thin polymer films (Schaffer et al. Nature 2000, 403, 874). For a large liquid volume fraction in the gap, varphi > or = 0.75, the coalescence of columns causes a phase inversion, leading to the formation of air columns or cylindrical holes trapped in the liquid matrix (air-in-liquid dispersion). Locally ordered aligned patterns are formed by imposing a spatial variation of the electrostatic field by using a topographically patterned electrode. For example, multiple rows/lines of liquid columns are formed near the edge of a step-like heterogeneity of the electrode and annular rings of ordered columns or concentric ripples are formed around a heterogeneous circular patch. Simulations predict that the electrode pattern is replicated in the film only when the pattern periodicity, L(p), exceeds the instability length scale on the basis of the minimum interelectrode separation distance, L(p) > or = lambda(m)-d(min). Thus, the formation of secondary structures can be suppressed by employing an electrode with deep grooves and stronger field gradients, which produces almost ideal templating. The number density of the electric field induced patterns can be altered by tuning the mean film thickness (or the volume fraction of liquid in the gap), periodicity and depth (amplitude) of the grooves on the top electrode, and the applied voltage. The implications are in electrostatic lithography, pattern replication in soft materials, and the design and interpretation of thin film experiments involving electric fields.

Deep intrauterine insemination in sow: results of a field trial

RiassuntoTraditional insemination techniques in pigs depose a high number of spermatozoa (2 to 3x109 spermatozoa) in a large volume of liquid (80-100 ml) into the cervix channel. The dose can be reduced markedly deposing it directly into the uterine horn. Previous studies showed that fertility rate and litter size were not significantly different with 5 or 15x107 spermatozoa in 10 ml into the uterus. The goal of this study was to determine the on-farm application and the reproductive performance of the deep intrauterine insemination (Firflex® probe, MAGAPOR, Spain) in sows. Experiments were conducted under field conditions in 4 commercial pig farms in the North of Italy (September 2003 and March 2004). A total of 166 crossbred multiparous sows were randomly selected after weaning and assigned to one of the following groups: Group 1 – traditional insemination with 3x109 sperm./dose, two insemination per oestrus (n=94) and Group 2 – deep intrauterine insemination with 15x107 sperm./dose, one insemination per oestrus (n=72). Different technicians in each farm performed the inseminations. Fertility rate was verified by transcutaneous ultrasonography; the total number of born and the number of alive born were counted at farrowing. Analysis of variance using the GLM procedure of SAS (SAS/STAT, 2000) was used to determine the effect of insemination technique, parity, period, farm and their interaction on the main effects of fertility rate and litters size. Fertility rate of Group 2 (50.5%) was significantly lower (P≤0.01) than those achieved after a traditional insemination (77.8%). The interaction between the insemination group and the period of trial was significant (P≤0.01), pointing out increasing results during the second period for deep intrauterine insemination. Prolificacy was significant lower (total born, P≤0.05, and born alive, P≤0.01) for Group 2. In conclusion, the results indicate that deep intrauterine insemination might realize suitable results with respect of fertility, even if the adverse effects on prolificacy will need to be further tested. The potential advantage for the pig industry occurs if technicians acquire the specific practice.

Delayed thermal explosion in flammable gas containing fuel droplets: Asymptotic analysis

The problem of thermal explosion in a flammable gas mixture with addition of volatile fuel droplets is studied based on the asymptotic method of integral manifolds. The model for the radiative heating of droplets takes into account the semitransparency of droplets. A simplified model for droplet heat-up is used. The results of the analysis are applied to the modelling of thermal explosion in diesel engines. Two distinct dynamical situations have been considered, depending on the initial droplet concentration. These are ‘far zone’ (small initial liquid volume fraction and small droplet radii) and ‘near zone’ (large initial liquid volume fraction and large droplet radii). The conditions of the first zone are typical for the areas in the combustion chamber which are far from the fuel injectors, while the conditions of the second zone are typical for the areas in the combustion chamber which are relatively close to the fuel injectors. It has been pointed out that small droplets’ heating and evaporation time in the far zone is smaller than the chemical ignition delay of the fuel vapor/air mixture. The total ignition delay decreases with increasing initial gas temperature. In the near zone for large droplets, the process starts with the initial gas cooling and slight heating of droplets. This is followed by a relatively slow heating of gas due to the chemical reaction, and further droplet heating. The total ignition delay in the near zone is larger than in the far zone. It is expected that before thermal explosion in the near zone takes place, the droplets break up and are removed from this zone. In optically thick gas effects of thermal radiation are negligible for small droplets but are noticeable for large droplets.

Removal of Chromium from Tannery Effluents by Adsorption

Tannery effluent is characterized not only by heavy loads but also with toxic heavy metals especially chromium ions. Chromium is considered an important source of contamination due to large volume of exhaust liquid discharged and solid sludge produced. Details on adsorption studies were carried out using synthetic chromium salts (chromium chloride) as adsorbate, and cement kiln dust (a waste from white cement industry) as adsorbent. Equilibrium isotherms have been determined for the adsorption of chromium ions on cement kiln dust. Kinetic study provided that the adsorption process is diffusion controlled. The experimental results have been fitted using Freundlich, Langmuir, and Redlich Peterson isotherms. The maximum adsorption capacity of cement kiln dust was found to be 33 mg/g. Industrial tannery effluent (22-mg/L chromium and COD 952 mg/L) was also treated by cement dust. The treated effluent (using 20 g cement dust per 1 L) contains only 0.6 mg/L chromium and COD 200 mg/L.

Physical research on the effect of microgravity on physical phenomena in cryogenic liquids; a general purpose onboard cryogenic facility for implementing this research on the International Space Station

A combined research plan, called “Boiling,” is created on the basis of several cryogenic research projects developed by experts in Russia and Ukraine for the International Space Station. The “Boiling” plan includes eight initial experiments aimed at investigating the influence of microgravity on boiling, heat transfer, and hydrodynamics in liquid helium under normal or superfluid conditions. The experiments are supposed to be performed with individual cells all placed inside a single onboard cryogenic experimental facility. The experiments to be performed as part of the international research program have the following special features: several artificially simulated microgravity levels produced by rotating the experimental helium cryostat; visualization of the processes occurring in liquid helium; research on boiling and hydrodynamics in a large volume of stationary liquid and in a liquid flow through a channel. When the “Boiling” research plan is completed the onboard cryogenic facility created for the International Space Station should find applications in further scientific and experimental research with helium.

Fumed silica: Rheological additive for adhesives, resins, and paints

Fumed silica, a synthetic silicon dioxide, is a powerful rheological additive for resins and paints to introduce thixotropy or even a yield point. The rheological effectiveness of fumed silica is based on its ability to form percolating networks which immobilize large volumes of liquid. By a combination of advanced rheological experiments, spectroscopical investigations, and quantum chemical calculations it could be demonstrated that the formation and stability of the silica network is strongly influenced by particle-resin interactions. The results can be used to develop comprehensive models, which explain the rheological performance of different grades of fumed silica in different resins.

Pulsed high voltage electric discharge disinfection of microbially contaminated liquids

To examine the use of a novel multielectrode slipping surface discharge (SSD) treatment system, capable of pulsed plasma discharge directly in water, in killing micro-organisms. Potable water containing Escherichia coli and somatic coliphages was treated with pulsed electric discharges generated by the SSD. The SSD system was highly efficient in the microbial disinfection of water with a low energy utilization (eta approximately 10-4 kW h l-1). The SSD treatment was effective in the destruction of E. coli and its coliphages through the generation of u.v. radiation, ozone and free radicals. The non-thermal treatment method can be used for the eradication of micro-organisms in a range of contaminated liquids, including milk, negating the use of pasteurization. The method utilizes multipoint electric discharges capable of treating large volumes of liquid under static and flowing regimes.

Initial crystallization kinetics in undercooled droplets

In large liquid volumes a variety of residual catalysts can limit the attainable undercooling. With a liquid droplet dispersion an effective nucleant isolation has yielded the largest undercooling for solidification and conditions where the nucleation process is the rate limiting step. Calorimetric measurements provide an effective means to determine the nucleation frequency in droplet samples. Since droplet samples are polydisperse in size, a full kinetics evaluation requires also a consideration of the size distribution which often obeys a log–normal relationship. With this information, the isothermal solidification rate constants may be determined to distinguish between a volume dependent process and a heterogeneous surface area dependent mechanism. An additional study of heterogeneous nucleation kinetics is possible in droplets containing well-defined solid catalyst surfaces in contact with the liquid which undercool to a clear nucleation onset. Suitable two-phase liquid+solid droplet samples may be generated in eutectic and peritectic alloys following thermal cycling and allow for a further analysis of the rate controlling kinetics.