Degree Of Dilution Research Articles

Analysis of body fluid mixtures by mtDNA sequencing: An inter-laboratory study of the GEP-ISFG working group

The mitochondrial DNA (mtDNA) working group of the GEP-ISFG (Spanish and Portuguese Group of the International Society for Forensic Genetics) carried out an inter-laboratory exercise consisting of the analysis of mtDNA sequencing patterns in mixed stains (saliva/semen and blood/semen). Mixtures were prepared with saliva or blood from a female donor and three different semen dilutions (pure, 1:10 and 1:20) in order to simulate forensic casework. All labs extracted the DNA by preferential lysis and amplified and sequenced the first mtDNA hypervariable region (HVS-I). Autosomal and Y-STR markers were also analysed in order to compare nuclear and mitochondrial results from the same DNA extracts. A mixed stain prepared using semen from a vasectomized individual was also analysed. The results were reasonably consistent among labs for the first fractions but not for the second ones, for which some laboratories reported contamination problems. In the first fractions, both the female and male haplotypes were generally detected in those samples prepared with undiluted semen. In contrast, most of the mixtures prepared with diluted semen only yielded the female haplotype, suggesting that the mtDNA copy number per cell is smaller in semen than in saliva or blood. Although the detection level of the male component decreased in accordance with the degree of semen dilution, it was found that the loss of signal was not consistently uniform throughout each electropherogram. Moreover, differences between mixtures prepared from different donors and different body fluids were also observed. We conclude that the particular characteristics of each mixed stain can deeply influence the interpretation of the mtDNA evidence in forensic mixtures (leading in some cases to false exclusions). In this sense, the implementation of preliminary tests with the aim of identifying the fluids involved in the mixture is an essential tool. In addition, in order to prevent incorrect conclusions in the interpretation of electropherograms we strongly recommend: (i) the use of additional sequencing primers to confirm the sequencing results and (ii) interpreting the results to the light of the phylogenetic perspective.

CONCENTRATION AND DAILY EXCRETION OF URANIUM IN URINE OF JAPANESE

A study was undertaken to investigate uranium concentrations in urine samples for unexposed Japanese individuals and to evaluate uranium daily excretion. Uranium concentrations were measured with inductively coupled plasma mass spectrometry after microwave-assisted digestion and online separation using the UTEVA extraction chromatographic resin. The concentrations ranged from 0.8 to 35.6 ng of uranium per liter of urine (median 4.5 ng L(-1)). Urinary uranium was normalized relative to the creatinine concentration in order to compensate for the degree of urine dilution. Creatinine-normalized values ranged from 1.2 to 17.8 ng of uranium per gram of creatinine (median 7.4 ng g(-1) creatinine). These results corresponded to the lower end of urinary uranium reported for unexposed populations. The level of daily excreted uranium was calculated as 6.45 ng d(-1) (median value) using ICRP recommended values for 24-h creatinine excretion. These data along with literature data on uranium dietary intake for Japanese populations were used to estimate the uranium gastrointestinal absorption fraction (f(1)). The median f(1) value was calculated to be 0.007. Statistical analysis was done to investigate statistical differences and relationships between the studied variables.

Chemical oxygen-iodine laser with CO2 buffer gas

The efficient power operation in a chemical oxygen-iodine laser for subsonic and supersonic modes has been demonstrated. It is shown that the substitution of the buffer gas N2 by CO2 does not cause any significant variation in the dependence of the output power on the degree of dilution of the active medium. The maximum power was 581W for the flow rate of molecular chlorine 22mMol∕s that corresponds to a chemical efficiency of ηchem=29%.

The haemodilution enhanced onset of coagulation as measured by the thrombelastogram is transient

Crystalloid haemodilution has been widely found to enhance coagulation onset, but the duration of this effect has never been documented. Twelve healthy, consenting volunteers had a rapid infusion of 14 mL kg-1 of normal (0.9%) saline. Blood samples were taken, prior to (control), and immediately after (30 min) the rapid saline infusion was completed (30 min). They were then repeated at regular intervals up to 120 min. Haematocrit/platelet counts were taken to determine the degree of dilution and thrombelastograms, with and without platelet antagonists (ReoPro, Abciximab), were measured in all samples. Antithrombin levels were selectively measured. The haematocrit and platelet count showed a rapid dilutional decrease at 30 min (mean of -12.2% and -14.4%, respectively), with values returning towards baseline within 15 min after finishing the infusion. There was a significantly faster onset of coagulation (decrease in r-time) in the post-infusion sample (30 min) compared to control (P<0.05), again returning towards normal as the dilution effect was reversed. Similar thrombelastograms findings were evident in the plasma factor only group (platelets inhibited by ReoPro). Antithrombin levels changed in keeping with the haemodilution effect (P<0.0001). There was a linear relationship between antithrombin and thrombelastograms r-time (P=0.012). The faster onset of coagulation brought on by haemodilution return towards normal as the dilutional effect is reversed. This effect is mediated through plasma clotting factors. Of interest is the significant inverse correlation of the onset of coagulation increasing as the antithrombin levels decreased with dilution.

Magnetic stirring during laser welding of aluminum

The use of magnetic fields to influence melt flow is a well-established method, e.g., in foundry technology. For arc welding processes (especially tungsten inert gas welding), a process called magnetic stirring was first proposed, patented, and investigated in the 1970s. The central aim was to improve (by the help of an alternating magnetic field coaxial with the arc axis) weld quality especially in aluminum by the combined effects of arc current and magnetic field. It was established that such fields are indeed capable of influencing weld bead appearance, of increasing the degree of dilution, of decreasing pore formation and of producing a finer grain structure. However, the process never gained wide industrial acceptance. In the late 1990s, some efforts have been taken to apply constant magnetic fields to laser welding processes, aiming at influencing weld geometry, reducing porosity, and potentially increasing welding speed. However, neither have any detailed statements been made on possibilities to influence melt flow and, consequently, filler metal distribution, nor on the application of alternating magnetic fields on laser welding. To help this situation, basic studies on magnetically influencing melt flow during laser welding of aluminum have been conducted. To that end, alternating fields have been coaxially applied with magnetic flux densities up to 60 mT and frequencies in the range of 0–20 Hz. It was demonstrated by the help of a specially developed method that, depending on the parameters chosen, such fields are indeed capable of influencing melt flow and weld pool dilution, thus “stirring” the weld metal. The results have been so promising that further investigations will be conducted, also focusing on laser hybrid welding especially of hot-cracking sensitive aluminum alloys.

Pretreatment and biotreatment of saline industrial wastewaters

Wastewater from an Akzo Nobel production site contains more than 50 g/l total dissolved salts, mainly chlorides and sulphates, and is currently being treated after 10-20 x dilution. Biological treatment of undiluted or less diluted wastewater is very desirable for environmental and economic reasons. Possibilities were investigated in laboratory scale reactors to treat this highly saline and high strength wastewater aerobically, either after long adaptation or after removing part of the salts by a pretreatment. Adaptation and selection from mixed activated sludge populations took approximately 40 days to finally achieve a COD removal in aerobic treatment of 55-65% at two times dilution (11-16 g/l chloride and 5-7 g/l sulphate). Undiluted wastewater was not treatable. A higher removal percentage (> 80%) was possible at the original high salt concentration only when the sludge load was limited to approximately 0.4-0.5 kg COD/kg sludge/day. A longer adaptation time was required. Nanofiltration (NF) and crystallization could be used as a pretreatment to remove and recover up to 80% of the sulphate in the form of crystallized Glauber salt. Recovery strongly depended on the sulphate and chloride concentration in the NF concentrate and on crystallization temperature. The salt (sulphate) reduction through the NF improved the removal efficiency of a consecutive biotreatment only at a relatively low chloride level, demonstrating that the combination of nanofiltration-crystallization-aerobic biodegradation is less feasible for very saline wastewaters. Anaerobic pretreatment of saline waters turned out to be rather sensitive to high salinities. Only wastewater diluted to 10 g/l chloride could be treated well: sulphate concentration decreased by 80% and COD by 40%. Removal efficiencies of the combined anaerobic-aerobic treatment were approximately 80-85%, proving that this was a feasible route for 2-3 x diluted wastewater. The study has shown that several alternatives are available for treatment of the very saline wastewaters at a much lower degree of dilution than currently practiced.

Human risk assessment of organic contaminants in reclaimed wastewater used for irrigation

Current water quality guidelines for reclaimed wastewater have predominantly addressed risks associated with the presence of microbial organisms. Comparatively, chemical parameters have been largely overlooked or inadequately considered. Acceptable levels of chemical parameters will be dependant on the proposed reuse applications for the water and, in many cases, site-specific factors such as the degree of dilution with water from other sources. However, some general principals for the determination of acceptable levels of chemical contaminants in reclaimed water may be applied universally. This study describes a general risk-assessment approach to the determination of acceptable contaminant concentrations. It provides some analysis of the principal functions of hazard identification, exposure assessment, dose-response relationship characterisation and risk characterisation as they relate to chemical contaminants in reclaimed water. Examples of some key modelling calculations for this process are provided for three selected contaminants (chloroform, 1,1,2-trichloroethane and pyrene) during hypothetical irrigation of agricultural areas. Predicted environmental concentrations were calculated and compared with predicted no effect concentrations. The results of the hypothetical modelling exercise indicate that the contaminants considered in this theoretical analysis pose an acceptable risk to human health via the single exposure path considered (uptake through food grown in the irrigated soil).

Particle Size Effects on the Burning Velocity and the Range of Flammability in the SHS Process for Mo-Si System

Relevant to Self-propagating High-temperatuzre Synthesis (SHS) process for Mo-Si system, burning velocity and range of flammability are examined not only experimentally but also theoretically, by varying Mo particle size in a relatively wide range, as well as mixture ratio of Mo-to-Si, degree of dilution by MoSi2, and initial temperature. Although effects of the mixture ratio, degree of dilution, and initial temperature on the burning velocity are the same as those for other representative systems, the particle size effect has turned out to be quite different from those for these systems. It is found that with decreasing Mo particle size, the burning velocity first increases gradually, reaches a plateau, and then decreases steeply. The promoting effect of this burning behavior can be attributed to an increase in the heat generation rate, caused by an increase in the total particle surface that participates in the reaction; while the suppressing effect can be attributed to dilution by oxides, the portion of which in the particle increases with decreasing particle size. By the same token, it is found that the range of flammability for steady combustion is restricted, due to the heat loss from the flame. In order to further elucidate effects of dominant parameters on the burning velocities, range of flammability, and/or limit of steady combustion, theoretical study has also been conducted, based on the heterogeneous theory for the SHS flame propagation, with oxide-layer thickness over Mo particles taken into account in the formulation. It has turned out that the theoretical result for the burning velocity fairly represents the experimental result. Furthermore, range of steady combustion is found to be bounded by limits, upper one of which is due to suppression of the heat generation rate by increasing particle size, and lower one of which is due to dilution by the oxide-layer over Mo particles. It is also demonstrated that fair degree of agreement exists between the experimental and theoretical results, as far as the trend and approximate magnitude are concemed.

Effects of Dominant Parameters on Burning Velocity and Range of Flammability in SHS Process for Ti-Al System

Relevant to the self-propagating high-temperature synthesis (SHS) process for the Ti-Al system, burning velocity and the range of flammability are examined theoretically. The heterogeneous theory for SHS flame propagation, presented in the literature is used. It is found that the effects of particle size, mixture ratio, degree of dilution, and initial temperature on the burning velocity and/or the range of flammability are the same as those for other representative systems. It has been confirmed that even for the Ti-Al system, a parameter defined as a product of the burning velocity and the particle size can be useful in correlating experimental results for flame propagation. It has also been confirmed that a parameter defined as the square of particle size divided by the compact diameter can be useful in correlating experimental results for flame extinction. In addition, it has been demonstrated that a fair degree of agreement exists between theoretical results and experimental data in the literature, as far as the trend and approximate magnitude are concerned.

Effects of Layer Thickness on the Burning Velocity and the Range of Flammability in the SHS Process with Multi-Layer foils

Relevant to Self-propagating High-temperature Synthesis (SHS) process, burning velocity and range of flammability are examined theoretically. Use has been made of the heterogeneous theory for the SHS flame propagation in multi-layer foils, consisting of alternating layers of constituents, has been extended to multicomponent systems, by describing a premixed mode of bulk flame propagation supported by a non-premixed reaction that proceeds at the layer surface of a constituent with higher melting-point. The formulation allows for finite rate Arrhenius reaction at the layer surface, temperature-sensitive Arrhenius mass diffusion in the liquid phase, and existence of intermixed region between constituent layers. It is confirmed that thickness ratio of the constituent layers is related to mixture ratio and that thickness ratio of the intermixed region and the constituent layer is related to degree of dilution. Results show that the burning velocity first increases, reaches the maximum, and then decreases rapidly, with decreasing alloy layer thickness, and that the decrease in the burning velocity can be attributed to the increase in the substance in the intermixed region between constituent layers, playing a role of diluent. The range of flammability is also obtained by the general restriction that the combustion temperature should be higher than the melting point of a constituent with lower melting-point. In experimental comparisons, it has been demonstrated that the analytical results agree with available experimental data in the literature, indicating that the present formulation has captured the essential features of the adiabatic, heterogeneous SHS process.

Analysis of swelling behavior of poly(methacrylamide-co-methacrylic acid) hydrogels and effect of synthesis conditions on water uptake

An investigation of water uptake behavior of a novel pH-sensitive poly(methacrylamide-co-methacrylic acid) hydrogel system was carried out with two major objectives. First was to study the effect of various synthesis conditions like reaction temperature, initiator content and degree of dilution of feed mixture on the water absorbency of resulting hydrogels and the second was to interpret the water uptake data by various kinetic models. The 2.25 times dilution of the reaction mixture resulted in the formation of hydrogels with highest water uptake of 1423 ± 21% in the simulating intestinal fluid of pH 7.4 at 37 °C. Likewise, the optimum synthesis temperature and initiator concentration were found to be 80 °C and 11.04 × 10 −2 mM, respectively. The kinetic models proposed by Peppas and Hopfenberg were applied on the water uptake data to obtain the best fit. The enthalpy of mixing Δ H mix was also evaluated for hydrogels with varying concentrations of monomer acid in the feed mixture. Finally, the gels demonstrated sharp change in their water absorbency and mesh size of networks with pH of the swelling media, thus suggesting their strong candidature for being used as oral drug-delivery systems along the gastrointestinal tract.

Effect of magnetic dilution in Zn1−xMnxGa2Se4 (0&amp;lt;x&amp;lt;0.5)

The profound effect of magnetic dilution in Zn1−xMnxGa2Se4 with 0&amp;lt;x&amp;lt;0. 5 is demonstrated by the analysis of neutron powder diffraction and magnetic susceptibility data. All the members of the series show a defective stannite crystal structure and a random distribution of the Mn ions. The magnetic archetype system of Zn1−xMnxGa2Se4 with 0&amp;lt;x&amp;lt;0. 5 is not found to be MnGa2Se4 (the magnetic end member of the series with I4¯ symmetry) but, instead, a hypothetical compound with I4¯2m symmetry. The distance between the Mn ions along the various magnetic superexchange pathways is not seriously affected by the degree of dilution. However, the global magnetic interaction between manganese ions is found to be significantly higher than that expected for the classical magnetic dilution of the parent MnGa2Se4. A generally applicable method for the calculation of the correct Weiss temperature θ in diluted magnetic semiconductors is provided.

LATE TO MIDDLE JURASSIC SOURCE FACIES AND QUALITY VARIATIONS, SOUTH VIKING GRABEN, NORTH SEA

Source facies and quality of the Late to Middle Jurassic source rock system in the South Viking Graben between 58°N and 60°15'N are highly variable both regionally and stratigraphically. In order to assess the degree of variability and to create a model of source rock quality and potential, isochore maps of the syn‐ and post‐rift sections of the Upper Jurassic Draupne Formation and underlying Heather Formation were generated from seismic and well data, and maturity‐corrected Rock‐Eval data were used to generate quantitative maps of oil and gas potential. The thin post‐rift section at the top of the Draupne Formation is a rich oil‐prone source, while the up to 1,600 m thick syn‐rift section contains a mixture of Type III and Type II material with substantial amounts of gas‐prone and inert organic matter. The Heather Formation, which reaches modelled thicknesses of up to 930 m, is a lean source and is generally gas‐prone.Detailed analyses and interpretations of biomarker and isotopic characteristics support this upward increase in oil‐prone Type II material. The analytical parameters include increasing relative amounts of C27 regular steranes; decreasing ratios of C30 moretane relative to C30 hopane; and an increasing predominance of short chain n‐alkanes and progressively lighter isotopic values for saturate and aromatic fractions of source rock extracts. In addition, increasing amounts of 17α(H),21β(H)‐28,30‐bisnorhopane and decreasing amounts of C34 homohopanes relative to C35 homohopanes, as well as decreasing Pr/Ph ratios, suggest a general decrease in oxygenation upwards. Maps of average Pr/Ph ratios for the syn‐ and post‐rift Draupne Formation and for the Heather Formation are consistent with permanent water column stratification and gradual ascent of the O2:H2S interface from the Callovian to the Ryazanian.Interpretation of oil and gas potential maps, molecular parameters and estimates of sediment accumulation rates in combination suggest that the source facies of the upper, post‐rift Draupne Formation is controlled by widespread anoxia, reduced siliciclastic dilution and reduced input of gas‐prone organic and inert material; by contrast, the potential of the lower, syn‐rift Draupne Formation is strongly controlled by dilution by gas‐prone and inert organic matter resulting from mass flows and also by varying degrees of oxygenation. The oil and gas potential of the Heather Formation is mainly controlled by the degree of oxygenation and siliciclastic dilution.

05/01723 Molecular transport effects on turbulent flamepropagation and structure

Linear bifurcation and numerical techniques are employed to determine critical conditions for ignition in steady, counterflow, nonpremixed hydrogen-air systems, with varying degrees of nitrogen dilution of the fuel, at temperatures larger than the crossover temperature associated with the second explosion limit for hydrogen. Analysis of profiles of the radical pool at ignition reveals that, irrespective of the degree of dilution of the fuel or oxidizer streams, the O-atom steady state fails on the oxidizer side of the mixing layer. Therefore, at least three overall steps, with O and H atoms as the chain-branching species, are necessary to describe the ignition process. A simplified model with variable density, specific heat and transport properties, and with Stefan-Maxwell approximations for the diffusion velocities, is proposed to describe the structure of the H2O2N2 weakly reactive mixing layer. Results of bifurcation analysis with this flow-field model and a three-step reduced chemical-kinetic scheme show excellent agreement with results of numerical integration of the full conservation equations with detailed chemistry for all degrees of dilution of the fuel feed.

The use of percutaneous autologous bone marrow transplantation in nonunion and avascular necrosis of bone

During the development of normal bone in the young child, osteoblasts and then haematopoietic stem cells progressively colonise the cartilaginous matrix, resulting in its ossification to bone matrix.[1][1] It is at this time that red bone marrow appears in the skeleton, starting distally in the foot

Use of native or platelet count adjusted platelet rich plasma for platelet aggregation measurements

Background: It is still not clear whether native or platelet count adjusted platelet rich plasma (PRP) should be used for platelet aggregation measurements. Aim: To evaluate the necessity of using...

Thème de la séance académique du 1 er décembre 2004 : Situation technico-réglementaire en France des médicaments homéopathiques préparés par l’industrie

Many homeopathic medications are marketed in France on the basis of old national regulations: homeopathic medications with a common denomination (unit or complex products) whose former approval was transformed into a marketing authorization in 1984; "normal formulations" with a special denomination, often dating from before 1941 (date when drug approval was instituted) including certain produces whose marketing approval was obtained under different mechanisms but still sold today. After the EEC excluded homeopathic drugs from the "medication" directives, in 1975 the 92/72/EEC directive stated that beyond the normal requirements for quality and safety, the same obligations could not be required for homeopathic and allopathic medications. A "registration" system was thus instituted for "traditional" medications en lieu of marketing approval. This included a dual obligation: 1) abstention from claiming therapeutic indications, 2) avoiding any formulation which could carry a risk for the patients (i.e. oral and topical formulations exclusive and degree of dilution guaranteeing safety). Beyond this restrictive framework, these medications have marketing approval, but, for the specific features of homeopathic medications, the directive leaves it up to the member States with a "homeopathic tradition" to apply special rules for evaluating the results of clinical trials designed to establish safety and efficacy. For the efficacy feature, traditional use can be used as an argument for marketing approval (article R5143 CSP). In order to create a more rational technicoregulatory environment, older products marketed before 1994 are being "validated" by group according to a calendar established in 2003 and which should run from 2004 to 2012. At the end of this validation procedure, all manufactured homeopathic products will either receive marketing approval or be recorder in compliance with general or specific European regulations. In conclusion, we make a few personal comments which should be helpful for the reader to distinguish between therapeutic efficacy and therapeutic interest.

Influence of Magnetic Fields on Dilution during Laser Welding of Aluminium

In order to minimize the occurrence of hot-cracking phenomena in laser welding of hotcracking sensitive aluminum alloy sheets, it is a common technique to introduce silicon-containing filler wire into the weld metal. However, to achieve an optimum result, a homogenous distribution of not less than 2 % of silicon throughout the weld metal is strongly recommendable. Under certain circumstances, this may be a difficult task. One potential solution to achieve sufficient dilution and, consequently, a very homogenous silicon distribution might be the application of alternating magnetic fields. In foundry technology, the use of magnetic fields to influence melt flow is a wellestablished method. For TIG welding, a process called magnetic stirring was first investigated in the 1970s. It was sufficiently demonstrated by the help of an alternating magnetic field coaxial with the arc axis, that, among other effects, the degree of dilution can be increased and a refined grain structure is achieved. Since the late 1990s, some efforts have been taken to apply constant magnetic fields to laser welding processes. However, neither alternating fields nor potential effects on dilution have been in the focus of these investigations. To help this situation, basic studies on magnetically influencing melt flow during laser welding of aluminum have been conducted. To that end, alternating fields have been coaxially applied with magnetic flux densities up to 60 mT and frequencies in the range of 0 to 20 Hz. It was demonstrated by the help of a specially developed method that, depending on the parameters chosen, such fields are indeed capable of influencing melt flow and weld pool dilution, thus “stirring” the weld metal.

05/01195 Performance analysis and optimum criteria of an irreversible Braysson heat engine

Nonadiabatic heterogeneous flame propagation and extinction in self-propagating high-temperature synthesis (SHS) are analyzed based on a premixed mode of propagation for the bulk flame supported by the nonpremixed reaction of dispersed nonmetals in the liquid metal. The formulation allows for volumetric heat loss throughout the bulk flame, finite-rate Arrhenius reaction at the particle surface, and temperaturesensitive Arrhenius mass diffusion in the liquid. Results show that, subsequent to melting of the metal, the flame structure consists of a relatively thin diffusion-consumption/convection zone followed by a relatively thick convection-loss zone, that the flame propagation rate decreases with increasing heat loss, that at a critical heat-loss rate the flame extinguishes as indicated by the characteristic turning-point behavior, that the surface reaction is diffusion limited such that the nonlinear, temperature-sensitive nature of the system is actually a consequence of the Arrhenius mass diffusion, and that extinction is sensitively affected by the mixture ratio, the degree of dilution, the initial temperature of the compact, and the size of the nonmetal particles. An explicit expression is derived for the normalized mass burning rate, which exhibits the characteristic turning point and shows that extinction occurs when this value is reduced to e−1/2, which is the same as that for the nonadiabatic gaseous premixed flame. It is further shown that the theoretical results agree well with available experimental data, indicating that the present formulation captures the essential features of the nonadiabatic heterogeneous SHS processes and its potential for extension to describe other SHS phenomena.

Role of C2F4, CF2, and ions in C4F8∕Ar plasma discharges under active oxide etch conditions in an inductively coupled GEC cell reactor

Utilizing infrared diode-laser absorption spectroscopy (IRDLAS) and UV-Visible absorption spectroscopy (UV-Vis), we show that it is possible to make a near complete mass balance of etch reactants and products in a GEC inductively coupled fluorocarbon discharge while actively etching SiO2 substrates. Langmuir probe measurements were performed to measure the total ion current density. C2F4 and CF2 are shown to be the main dissociation products in a C4F8 plasma discharge. The C2F4 concentration decreases as the SiO2 etching rate increases, along with CF2 and CF radicals, suggesting a role in the SiO2 etching process. The addition of Ar to the C4F8 discharge increased the ion flux at the wafer surface, and the consumption rate of C2F4 relative to CF2. The increased ion flux enhanced the SiO2 etching rate, until at a very high degree of Ar dilution of C4F8∕Ar the etching rate became neutral limited. We also monitored SiF2 using UV-Vis absorption and CO by IRDLAS. In our work we found SiF2 and CO to be the prevalent Si and C gas phase etch products for the SiO2 etching process.