Multiple Chambers Research Articles

Pressures of Crystallization of Icelandic Magmas

Iceland lies astride the Mid-Atlantic Ridge and was created by seafloor spreading that began about 55 Ma. The crust is anomalously thick (� 20^40 km), indicating higher melt productivity in the underlying mantle compared with normal ridge segments as a result of the presence of a mantle plume or upwelling centered beneath the northwestern edge of the Vatnajo« kull ice sheet. Seismic and volcanic activity is concentrated in � 50 km wide neovolcanic or rift zones, which mark the subaerial Mid-Atlantic Ridge, and in three flank zones. Geodetic and geophysical studies provide evidence for magma chambers located over a range of depths (1� 5^21km) in the crust, with shallow magma chambers beneath some volcanic centers (Katla, Grimsvo« tn, Eyjafjallajo« kull), and both shallow and deep chambers beneath others (e.g. Krafla and Askja). We have compiled analyses of basalt glass with geochemical characteristics indicating crystallization of ol^plag^cpx from 28 volcanic centers in the Western, Northern and Eastern rift zones as well as from the Southern Flank Zone. Pressures of crystallization were calculated for these glasses, and confirm that Icelandic magmas crystallize over a wide range of pressures (0� 001 to � 1 GPa), equivalent to depths of 0^35 km. This range partly reflects crystallization of melts en route to the surface, probably in dikes and conduits, after they leave intracrustal chambers. We find no evidence for a shallow chamber beneath Katla, which probably indicates that the shallow chamber identified in other studies contains silica-rich magma rather than basalt. There is reasonably good correlation between the depths of deep chambers (417 km) and geophysical estimates of Moho depth, indicating that magma ponds at the crust^mantle boundary. Shallow chambers (57� 1km) are located in the upper crust, and probably form at a level of neutral buoyancy. There are also discrete chambers at intermediate depths (� 11km beneath the rift zones), and there is strong evidence for cooling and crystallizing magma bodies or pockets throughout the middle and lower crust that might resemble a crystal mush. The results suggest that the middle and lower crust is relatively hot and porous. It is suggested that crustal accretion occurs over a range of depths similar to those in recent models for accretionary processes at mid-ocean ridges. The presence of multiple stacked chambers and hot, porous crust suggests that magma evolution is complex and involves polybaric crystallization, magma mixing, and assimilation.

Physicochemical characterization of a modified cellulose acetate membrane for the design of oil-in-water emulsion disruption devices

In this paper, a new membrane separation process is presented. This process is based on a multiple chamber cell that allows the separation of oil from water by placing two membranes of different hydrophobicity in contact with the emulsion. Further chemical modifications of the membranes have been performed in order to vary their hydrophobicity in the perspective of optimizing the fractionation process via specific interactions between membrane and emulsion components. For this purpose, methylcellulose was modified with 1,2-epoxydodecane and incorporated in the membrane elaboration process. The modification of membrane surface chemical structure was demonstrated by ATR-FTIR and XPS experiments. Preliminary filtration tests are presented as well as future perspectives to optimize the membrane modification procedure.

Magma chamber evolution prior to the Campanian Ignimbrite and Neapolitan Yellow Tuff eruptions (Campi Flegrei, Italy)

The Campi Flegrei (Campanian Region, Italy) experienced two cataclysmic caldera-forming eruptions which produced the Campanian Ignimbrite (39 ka, CI) and the Neapolitan Yellow Tuff (15 ka, NYT). We studied the minor eruptions before both these large events to understand magma chamber evolution leading towards such catastrophic eruptions. Major, trace element, and Sr and Nd isotope compositions of pre-Campanian Ignimbrite and pre-Neapolitan Yellow Tuff products define distinct geochemical groups, which are here interpreted as distinct magma batches. These batches do not show any transitional trend towards the CI and NYT eruptions. The CI and NYT systems are decoupled geochemically and isotopically. At least one of the pre-CI and one of the pre-NYT erupted magma batches qualifies as mixing endmembers for the large CI and NYT eruptions, and thus, must have been stored in reservoirs for some time to remain available for the CI and NYT eruptions. The least evolved, isotopically distinct magma compositions that are typical of the last phases of the NYT and CI eruptions did not occur before caldera-forming events. Based on the new data, we propose the following scenario: Multiple magma chambers with distinct compositions existed below the Campi Flegrei before the CI and NYT eruptions and remained generally separated for some time unless new magma was recharged. In each case, one of the residing magma reservoirs was recharged by a new large-volume magma input of intermediate composition from a deeper differentiating magma reservoir. This may have triggered the coalescence of the previously separated reservoirs into one large chamber which fed the cataclysmic caldera-forming eruption. Large magma chambers in the Campi Flegrei may therefore be ephemeral features, interrupted by periods of evolution in individual, separated magma reservoirs.

Systems Modeling for Z-IFE Power Plants

A systems model has been developed for Z-IFE power plants. The model includes cost and performance scaling for the target physics, z-pinch driver, chamber, power conversion system and target/RTL manufacturing plant. As the base case we consider the dynamic hohlraum target and a thick liquid wall chamber with flibe as the working fluid. Driver cost and efficiency are evaluated parametrically since various options are still being considered. The model allows for power plants made up of multiple chambers and power conversion units supplied by a central target/RTL manufacturing plant. Initial results indicate that plants with few chambers operating at high yield are economically more attractive than the 10-unit plant previously proposed. Various parametric and sensitivity studies have been completed and are discussed.

On‐line quality assurance of rotational radiotherapy treatment delivery by means of a 2D ion chamber array and the Octavius phantom

For routine pretreatment verification of innovative treatment techniques such as (intensity modulated) dynamic arc therapy and helical TomoTherapy, an on-line and reliable method would be highly desirable. The present solution proposed by TomoTherapy, Inc. (Madison, WI) relies on film dosimetry in combination with up to two simultaneous ion chamber point dose measurements. A new method is proposed using a 2D ion chamber array (Seven29, PTW, Freiburg, Germany) inserted in a dedicated octagonal phantom, called Octavius. The octagonal shape allows easy positioning for measurements in multiple planes. The directional dependence of the response of the detector was primarily investigated on a dual energy (6 and 18 MV) Clinac 21EX (Varian Medical Systems, Palo Alto, CA) as no fixed angle incidences can be calculated in the Hi-Art TPS of TomoTherapy. The array was irradiated from different gantry angles and with different arc deliveries, and the dose distributions at the level of the detector were calculated with the AAA (Analytical Anisotropic Algorithm) photon dose calculation algorithm implemented in Eclipse (Varian). For validation on the 6 MV TomoTherapy unit, rotational treatments were generated, and dose distributions were calculated with the Hi-Art TPS. Multiple cylindrical ion chamber measurements were used to cross-check the dose calculation and dose delivery in Octavius in the absence of the 2D array. To compensate for the directional dependence of the 2D array, additional prototypes of Octavius were manufactured with built-in cylindrically symmetric compensation cavities. When using the Octavius phantom with a 2 cm compensation cavity, measurements with an accuracy comparable to that of single ion chambers can be achieved. The complete Octavius solution for quality assurance of rotational treatments consists of: The 2D array, two octagonal phantoms (with and without compensation layer), an insert for nine cylindrical ion chambers, and a set of inserts of various tissue equivalent materials of different densities. The combination of the 2D array with the Octavius phantom proved to be a fast and reliable method for pretreatment verification of rotational treatments. Quality control of TomoTherapy patients was reduced to a total of approximately 25 min per patient.

Incubation of Environmental Samples in a Diffusion Chamber Increases the Diversity of Recovered Isolates

The majority of microorganisms from natural environments cannot be grown in the laboratory. The diffusion-chamber-based approach is an alternative method that allows microorganisms to grow in their natural environment. An inoculum is sandwiched between semipermeable (0.03-mum-pore-size) membranes of the chamber, which is then returned to the source environment. The chamber allows for a free exchange of chemicals with the external milieu by diffusion while restricting the movement of cells. We used freshwater pond sediment to inoculate diffusion chambers and petri dishes. The diffusion chambers were incubated on top of the sediment for 4 weeks. Both chamber and petri dish cultivation resulted in the isolation of numerous representatives of Alpha-, Beta-, and Gammaproteobacteria; Actinobacteria; Firmicutes; and Bacteroidetes. However, the diffusion-chamber-based approach also led to the isolation of species from rarely cultivated groups, such as Deltaproteobacteria, Verrucomicrobia, Spirochaetes, and Acidobacteria. Material from the chambers was also transferred to new chambers in order to learn whether this will increase the recovery of isolates. Several isolates could be obtained only from material transferred through multiple diffusion chambers. This suggests that continuous cultivation in diffusion chambers adapts some microorganisms for growth under otherwise prohibitive in vitro conditions.

SU-FF-T-343: Peripheral Dose Variations with Different IMRT Delivery Systems

Purpose: To obtain an accurate assessment of the relationship between peripheral dose and beam modulation among three commercially available IMRT delivery systems. These systems differ as a consequence of collimator jaw behaviour during IMRT field delivery, with the Varian system using static jaw settings encompassing the fluence from all segments, the Elekta Synergy jaws conforming to individual segment and the Elekta Synergy-S maintaining a maximum collimated opening for all fields independent of MLC segment shape. Method and Materials: Fields with various degrees of modulation were created using Pinnacle 7.6C to deliver a uniform dose in phantom. Rotated rectangular apertures were used to engage both MLC leafs and jaws in aperture definition. Fields were characterized by an intensity modulation factor (IMF), defined as the ratio of the IMRT MU to that of an open field delivering the same dose. Multiple ionization chamber measurements were made for each delivery system outside the delivered field in solid water at 10cm depth. Results: The Elekta Synergy accelerator delivered the lowest peripheral doses. The Varian produced intermediate peripheral doses and the Elekta Synergy S produced the largest peripheral doses. For an IMF of 8, the peripheral doses 6cm from the field edge were 1.8%, 3.1% and 8.2% for the Elekta Synergy, Varian and Elekta Synergy S, respectively. Conclusion: Differences in peripheral dose levels were measured and compared among a number of available delivery systems for IMRT type treatments. As with all radiation treatments, efforts should be made to minimized the dose to normal tissues. The results of this study extend the information available for balancing treatment benefits against the risk of late side effects and secondary cancer induction, particularly when a choice of delivery platforms is available to a center.

Making MUSIC: A multiple sampling ionization chamber

A multiple sampling ionization chamber (MUSIC) was developed for use in conjunction with the Atlas scattering chamber (ATSCAT). This chamber was developed to study the (α,p) reaction in stable and radioactive beams. The gas filled ionization chamber is used as a target and detector for both particles in the outgoing channel (p+ beam particles for elastic scattering or p+residual nucleus for (α,p) reactions). The MUSIC detector is followed by a Si array to provide a trigger for anode events. The anode events are gated by a gating grid so that only (α,p) reactions where the proton reaches the Si detector result in an anode event.The MUSIC detector is a segmented ionization chamber. The active length of the chamber is 11.95in. and is divided into 16 equal anode segments (3.5in.×0.70in. with 0.3in. spacing between pads). The dead area of the chamber was reduced by the addition of a Delrin snout that extends 0.875in. into the chamber from the front face, to which a mylar window is affixed. 0.5in. above the anode is a Frisch grid that is held at ground potential. 0.5in. above the Frisch grid is a gating grid. The gating grid functions as a drift electron barrier, effectively halting the gathering of signals. Setting two sets of alternating wires at differing potentials creates a lateral electric field which traps the drift electrons, stopping the collection of anode signals. The chamber also has a reinforced mylar exit window separating the Si array from the target gas. This allows protons from the (α,p) reaction to be detected. The detection of these protons opens the gating grid to allow the drift electrons released from the ionizing gas during the (α,p) reaction to reach the anode segment below the reaction.

On-chip microfluidic biosensor for bacterial detection and identification

In this paper, we have developed a simple and rapid method for the detection and identification of bacteria using a microfluidic lab-chip. The microfluidic chip utilizes impedance-based measurement to (1) detect cells and (2) identify them when used in conjunction with immobilized monoclonal antibodies. Bacteria in suspension passing through the microfluidic chamber are recognized by antibodies and selectively immobilized on the functionalized glass surface, thereby increasing the measured impedance within the chamber. Continuous perfusion of bacteria suspension through the derivatized chamber not only identifies specific bacteria but also enhances the chamber's detection sensitivity by accumulating bacteria on the chamber wall over time; this approach would be useful for detecting low concentrations of bacteria. To demonstrate this approach, we showed that the prototype sensor could detect 9 × 10 5 CFU mL −1 E. coli (BL21( DE3)) in the solution by consecutive perfusions. The chip sensitivity with immobilized bacteria is governed by height of sensing chamber, and ∼10 4 CFU mL −1 of E. coli could easily be detected when a shallower chamber (2 μm high) was used. The selectivity of the sensor was tested using a suspension of two bacterial strains, E. coli and M. catarrhalis. The sensor chip is simple to use, requires minuscule samples, and eliminates extensive cell culture processes. Development of more advanced lab-chips with multiple chambers containing different antibodies that allow simultaneous detection of different bacteria strains will be a natural extension of this work.

Cell-based high content screening using an integrated microfluidic device

High content screening (HCS) has quickly established itself as a core technique in the early stage of drug discovery for secondary compound screening. It allows several independent cellular parameters to be measured in a single cell or populations of cells in a single assay. In this work, we describe high content screening for the multiparametric measurement of cellular responses in human liver carcinoma (HepG2) cells using an integrated microfluidic device. This device consists of multiple drug gradient generators and parallel cell culture chambers, in which the processes of liquid dilution and diffusion, micro-scale cell culture, cell stimulation and cell labeling can be integrated into a single device. The simple assay provides multiparametric measurements of plasma membrane permeability, nuclear size, mitochondrial transmembrane potential and intracellular redox states in anti-cancer drug-induced apoptosis of HepG2 cells. The established platform is able to rapidly extract the maximum of information from tumor cells in response to several drugs varying in concentration, with minimal sample and less time, which is very useful for basic biomedical research and cancer treatment.

Behavioural responses in wild cod ( Gadus morhua L.) exposed to fish holding water

Local fishermen in several areas of Norway assert that salmon farms have caused the wild migrating cod to change their migratory behaviour, so that they no longer enter their natural spawning grounds in the fjords. If the asserted changes in behaviour of wild cod populations can be linked to establishment of salmon farms, water-soluble odorants are then possible candidates to explain such a connection. Chemical stimulants are important to the individual fish's conception of the surrounding environment. High density stocks of fish in a farm are expected to release large amounts of waterborne information. The present laboratory experiments were conducted to test behavioural responses in Atlantic cod exposed to water containing metabolites and waste from farmed salmon. The trials were conducted on single fish in a multiple chamber preference system. The results show that migrating wild Atlantic cod chose to spend more time in chambers without addition of water from the salmon tank, regardless of their maturation status, and even at very low concentrations (0.2%). The avoidance is probably due to presence of chemical compounds with olfactory properties from salmon, since anosmic cod did not elicit such response. Farmed cod, on the other hand, does not avoid water from the salmon tank, and stationary wild cod caught nearby a fish farm had a less pronounced response as compared to wild migrating cod. The response seen is not species specific, as wild migrating cod responded similar to water from a tank holding farmed cod as to water from salmon. These results do not preclude fishermen's observations that cod change their behaviour in areas with fish farming activity. Such a change in behaviour could be a response to water-soluble odorants, but needs to be validated and detailed in further laboratory experiments as well as in nature before any conclusions can be made.

新しい形態のキット製品: マルチチャンバーバッグ型粉末注射剤/溶解液キット

新しい形態のキット製品: マルチチャンバーバッグ型粉末注射剤/溶解液キット

Stability-indicating HPTLC assay for leuprolide acetate

A new stability-indicating HPTLC assay has been established for leuprolide acetate. Silica gel 60F 254 was used as stationary phase. Samples and reference standards were applied to the same precleaned and activated HPTLC plates and chromatography was performed in an automated multiple development chamber (AMD2) with five-step isocratic incremental multiple development with 1 min drying time between each step and layer conditioning with the mobile phase before each development. The mobile phase, ethyl acetate-methanol-25% aqueous ammonia, 60 + 30 + 10, resulted in dense, compact zones for the analyte and related substances. Leuprolide acetate was subjected to acidic, basic, and oxidative degradation. The peaks of the degradation products were well resolved from the main peak with significantly different migration distances. Densitometric evaluation was performed at λ = 280 nm. The calibration function of the analyte was linear in the range 107–422 ng and the correlation coefficient was 0.9914. The limits o...

Rapid sympathetic cooling to Fermi degeneracy on a chip

Neutral fermions present new opportunities for testing models of many-body quantum systems, realizing precision atom interferometry, producing ultra-cold molecules, and investigating fundamental forces. However, since they were first observed1, quantum degenerate Fermi gases (DFGs) have continued to be challenging to produce, and have been realized in only a handful of laboratories2,3,4,5,6,7,8,9,10. In this letter, we report the production of a DFG using a simple apparatus based on a microfabricated magnetic trap. Similar approaches applied to Bose–Einstein condensation of 87Rb (refs 11,12) have accelerated evaporative cooling and eliminated the need for multiple vacuum chambers. We demonstrate sympathetic cooling for the first time in a microtrap, and cool 40K to Fermi degeneracy in just six seconds—faster than has been possible in conventional magnetic traps. To understand our sympathetic cooling trajectory, we measure the temperature dependence of the 40 K–87Rb cross-section and observe its Ramsauer–Townsend reduction.

Particle Control in Dielectric Etch Chamber

A methodology for evaluating and controlling particle performance in a dielectric etch system is developed and presented. Analysis of particle samples, collected from premature chamber failures for out-of-control particle levels, suggests sputtering of the upper electrode during etching is a key modulator to this problem. To eliminate such sputtering, we designed a series of experiments with the objective of identifying a between-lot conditioning (BLC) process capable of creating a uniform and solid layer of polymer coating that covers the entire upper electrode of a parallel plate, RF, magnetically enhanced reactive ion etch system. An approach comprising a series of short wafer processing marathon runs, with polymer coverage and particle performance as the two main responses, was then used to identify a candidate process for BLC recipe and usage frequency. Adequate non flaking polymer coverage of the upper electrode was achieved by utilizing a BLC process based on octafluoro-cyclobutane/oxygen/argon/carbonmonoxide [C/sub 4/F/sub 8//O/sub 2//Ar/CO] chemistry at high RF power and short transit time settings. The candidate process was then optimized and tested in a manufacturing pilot involving multiple production etch chambers and was subjected to extensive process performance metrics. Based on this methodology, the optimized BLC was successful in controlling defects and in attaining the mean wafer between wet clean goal for the etch system under investigation.

Flutes with multiple chambers that share compound bisected toneholes

One exemplary embodiment of a flute comprises first and second chambers in which sound is resonated and a tonehole disposed at and shared by the first and second chambers. The tonehole is coverable by a single finger of an operator's hand and is configured to facilitate airflow communication from the first chamber through the tonehole and airflow communication from the second chamber through the tonehole. An exemplary embodiment of an ocarina comprises an instrument body having a first chamber having a first airway through which air is received and a second chamber having a second airway through which air is received, a top cover disposed on the instrument body, an upper tonehole disposed through the top cover to facilitate airflow through the first chamber and airflow through the second chamber, and a bottom cover disposed on the instrument body. Another embodiment of a flute comprises first and second chambers in which sound is resonated, a blowing aperture through which air is provided into the first and second chambers, and a tonehole disposed at and shared by the first and second chambers.

Evaluation of the Performance of a New Continuous Spheronizer

ABSTRACTThis study aims to evaluate the performance of a new continuous spheronizer with multiple concentric chambers. The characteristics of the pellets produced in the different chambers (moisture content, mechanical strength, density, sphericity, size, release of a drug) were compared by multivariate analysis of variance (MANOVA), when different times of spheronization and chambers were considered. The statistical analysis has shown that both the diameter of the chambers and the time of spheronization affected the properties of the pellets, and, thus, they must be considered when the spheronizer is used. To minimize these effects all the forming pellets should be processed in all chambers for a defined period of time.

Vessel motion measurement in real-time using movement detection at multiple regions of interest

A vessel motion detection algorithm has been implemented for the measurement of multiple lymphatic chamber diameters via pre-recorded VHS tape (PAL, 25 Hz). The method differs significantly from previous attempts based on edge-detection, in that it employs center of mass of pixel brightness in the vessel wall based on a Kalman filtered image subtracted from a Kalman filtered background. The operation of the algorithm confirms that it is able to detect accurately the full constriction–relaxation cycle of the vessel and produce data that meets high standards of tolerance. The procedure is well suited for real-time measurement of lymphatic and blood vessel constrictions in vitro or in vivo at multiple sites so long as the object under measurement is sufficiently differentiated from its background.

Intracardiac Thrombosis in Multiple Chambers and Descending Aorta Manifested as Systemic and Pulmonary Thromboembolism

We report a case with multiple thrombosis that underwent sudden circulatory collapse due to acute pulmonary embolism and ischemic stroke. Further confirmed by transesophageal echocardiography, the thrombus in both atria was detected by transthoracic echocardiography. In addition, patent foramen ovale and another thrombus in the descending aorta were readily identified by transesophageal echocardiography. Aspirin was prescribed and thrombi disappeared 1 month later. Our case report suggests that patients undergoing sudden collapse with unexplained hypoxemia and new neurological deficit secondary to coexistence of pulmonary and systemic embolism should be promptly evaluated by echocardiography, especially transesophageal one, with high suspicion for paradoxical embolism.

Why Do Some Democratic Countries Join More Intergovernmental Organizations Than Others?*

Objective. This study investigates whether variations in democratic institutions influence foreign policy outcomes. Specifically, it examines whether democracies differ systematically in their inclination to join international organizations.Methods. The study performs negative binomial estimation analysis of the relationship between IGO membership and variations in democratic structure.Results. It finds that a more competitive party system and multiple legislative chambers, especially for wealthy and stable Western democracies, contribute to more IGO memberships.Conclusions. From our findings we infer that consensus democracies adopt a kinder, gentler foreign policy that includes more willingness to participate in multilateral, cooperative international institutions, relying on negotiation and compromise to reach mutually acceptable arrangements for dealing with common problems. This assertion fits with a fundamental Kantian thesis: that the more representative and accountable a society's political institutions are, the more peaceful that society is likely to be.