Capillary Chamber Research Articles

Study on in situ mass spectrometry leak detection technique of working fluid in spacecraft electric propulsion system

Helium mass spectrometry leak detection technology requires that the leak detection medium of spacecraft test object is helium, but the general working medium of spacecraft electric propulsion system is xenon. The existing helium mass spectrometry leak detection technology can not realize the in-situ leak detection of all kinds of working media. The in situ mass spectrometry leak detection technology of spacecraft working medium based on mass spectrometry has been widely concerned for its advantages of direct leak detection of working medium and obtaining real leak rate, but the sampling and leak detection of mass spectrometry under atmospheric environment is one of its difficulties. In this paper, a leak detection model and test system of spacecraft working medium in situ mass spectrometry are established, and theoretical and experimental studies are carried out. The research results show that, The leak detection sensitivity of in situ working mass spectrometry is better than 1.0 × 10−8 Pa m3/s by shunt current limiting sampling method in atmospheric environment. The appropriate shunt pumping speed and shunt chamber pressure have important influence on in situ leak detection of working medium. When the pressure of capillary shunt chamber is higher than 550Pa, the test system has better stability and repeatability. Not only the background noise of the leak detection by mass spectrometry is reduced, the detection accuracy is improved, and the response time of the system is shortened.

AI Driven Lab-on-Chip Cartridge for Automated Urinalysis

After haematology, urinalysis is the most common biological test performed in clinical settings. Hence, simplified workflow and automated analysis of urine elements are of absolute necessities. In the present work, a novel lab-on-chip cartridge (Gravity Sedimentation Cartridge) for the auto analysis of urine elements is developed. The GSC consists of a capillary chamber that uptakes a raw urine sample by capillary force and performs particles and cells enrichment within 5 min through a gravity sedimentation process for the microscopic examination. Centrifugation, which is necessary for enrichment in the conventional method, was circumvented in this approach. The AI100 device (Image based autoanalyzer) captures microscopic images from the cartridge at 40x magnification and uploads them into the cloud. Further, these images were auto-analyzed using an AI-based object detection model, which delivers the reports. These reports were available for expert review on a web-based platform that enables evidence-based tele reporting. A comparative analysis was carried out for various analytical parameters of the data generated through GSC (manual microscopy, tele reporting, and AI model) with the gold standard method. The presented approach makes it a viable product for automated urinalysis in point-of-care and large-scale settings.

Low-Potential Operation of Direct Electron Transfer Biosensor Strip With Single-Walled Carbon Nanotubes and Flavin Adenine Dinucleotide Glucose Dehydrogenase

In this study, the low-potential operation (+0.05 V vs. Ag/AgCl) of a direct electron transfer (DET) glucose biosensor strip with a small-volume (2 μL) electrochemical capillary chamber is demonstrated. We constructed a DET formation in which de-bundled single-walled carbon nanotubes (SWCNTs) were placed near the reaction center pocket of flavin adenine dinucleotide glucose dehydrogenase (FAD-GDH). The DET biosensor has the advantage of long-term stability, unlike an electron transfer mediator, which is naturally reduced to cause sensing malfunction in a mediated electron transfer biosensor, adopted in commercial devices. However, DET biosensors still have a high working potential owing to their overpotential. In this article, we have resolved this issue via a very short interval (1 ms) voltage application (+0.4 V) that reduced the onset potential, in other words, enhanced the current owing to an enzymatic reaction. The DET biosensors had a sensitivity of 0.055 μA (mg/dl) <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> , a linear dynamic range of 0-750 mg/dL, and a detection limit of 0.9 mg/dL.

Amperometric Biosensor Strip With Carbon Nanotube and Ketone Body 3-Hydroxybutyrate Dehydrogenase

We propose an amperometric biosensor strip for the detection of ketone body 3-hydroxybutyrate (3HB) in serum. The biosensor strip has a small volume ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\approx 2 ~\mu \text{L}$ </tex-math></inline-formula> ) capillary chamber. The working electrode consists of carbon nanotubes (CNTs) and 3HB dehydrogenase (3HBDH). The CNTs are dispersed in aqueous media with sodium cholate (SC) surfactant and mixed with HBDH solution. Ultraviolet–visible, electrochemical impedance spectroscopy (EIS), and atomic force microscopy (AFM) demonstrated that the CNTs were well dispersed in aqueous solution. Any type of CNT enhances the current owing to an enzymatic reaction without an electron transfer mediator. A small amount of HBDH/CNT solution is dipped into a small-area (1.5 mm2) electrode and sealed with a coversheet to make the reaction chamber. The sensor can detect 3HB in human serum within the range of 0.05–4.4 mM, which can cover physiological use. The response time is 15 s.

Modeling and Experimental Verification of Plasma Jet Electromagnetic Signals

Herein, we discuss the modeling and verification of RF sensed signals in a simple plasma channel (plasma jet) at the generator frequency of f = 13.56 MHz, assuming plasma discharge at atmospheric pressure. The actual experiment was preceded by a basic numerical analysis and evaluation of several variants of the geometric/numerical model of a simple plasma channel formed in a glass capillary chamber; this step was performed with different electrode configurations. The analyses also included the impact of the location of the sensing element (i.e., the antenna) on the resulting evaluated electromagnetic signal. Furthermore, a numerical model with concentrated parameters facilitated a comparative analysis centered on the impact of plasma concentration and composition in the monitored electromagnetic RF spectrum of the channel. The theoretical outputs were verified via experiments and compared. This methodology finds use in the radio-frequency evaluation of plasma parameters in both simple capillary nozzles and more complex, slit-designed plasma chambers.

Geometric factors affecting capillary discharge jet length in atmospheric pressure air.

The capillary discharge triggered by a pulse source can produce a certain length of plasma jet. In this paper, the physical process of the capillary discharge jet is analyzed, and it is pointed out that the capillary plasma-jet length is significantly affected by the expansion pressure caused by the arc discharge in the capillary chamber. The greater the pressure in the capillary chamber is, the longer the jet length. The experimental setup of the capillary discharge is established in atmospheric pressure air. The influence of the surface distance along the capillary wall, the diameter of the capillary cathode, and the length of the cathode tip on the plasma-jet length is studied under a specific trigger pulse. The experimental results show that the greater the deposited energy density in the capillary chamber is, the longer the plasma jet length. As the surface distance increases, the energy deposited in the arc channel increases first and then tends to be saturated. There is an optimum surface distance to maximize the energy density in the capillary chamber, while the plasma jet length is the longest.

GPVI Interaction with Polymerized Fibrin Boosts Thrombin Generation and Thrombus Growth

Background: Fibrin, the end product of the coagulation cascade, consolidates the platelet plug at site of thrombosis: polymerized fibrin supports platelet adhesion under low and high shear rate conditions (Hantgan RR et al., Thromb Haemost 1992) and triggers platelet procoagulant activity (Beguin S et al., Blood 1999). These responses are largely independent of the integrin αIIβ3 and are carried by a yet ill-defined receptor. Platelet glycoprotein VI (GPVI) has a well-established key role in the initiation of thrombosis since it supports collagen-mediated platelet activation but it has recently been recognized to interact with other macromolecules such as fibronectin, vitronectin and laminins. We hypothesized GPVI could be the “missing” platelet receptor of fibrin.Aim of the study: to challenge the hypothesis that glycoprotein VI (GPVI) could be a functional fibrin receptorMethods: Thrombin generation was measured using calibrated automated thrombogram (CAT) in PRP from healthy volunteers, four GPVI-deficient patients and one patient with a fibrinogen deficiency. CAT was also performed on washed platelets mixed with prothrombin complex (FII, FVII, FIX, FX), antithrombin and fibrinogen. GPVI was blocked using the Fab of the monoclonal antibody 9O12. Fibrin polymerization was blocked using the GPRP peptide. GPVI binding to fibrin was measured in vitro using recombinant soluble GPVI (GPVI-Fc). Flow based adhesion assays were performed in capillary chambers coated with polymerized fibrin at variable shear rates and platelet morphological changes analyzed by scanning electron microscopy. The formation of fibrin-platelet thrombi was visualized by perfusing recalcified blood containing A647 fibrinogen in flow chambers (Vena8 Fluoro+ Cellix) coated with collagen and tissue factor. In a second step, the perfusion of hirudinated blood in which platelets were stained by A488-RAM1 allowed to visualize platelet recruitment by fibrin rich clots.Results: Thrombin generation triggered by tissue factor was impaired in the PRP of patients with a GPVI deficiency or in the presence of the Fab 9O12 as indicated by a respective decrease in the peak height of 45 and 25% as compared to controls. This effect was observed regardless the trigger of thrombin generation and required platelet activation. Measuring thrombin generation in a purified system showed that fibrinogen dose-dependently increased the thrombin peak by up to 150% at 3 mg/mL but the Fab 9O12 blunted this effect. Moreover, the Fab 9O12 had no effect on thrombin generation in the PRP of a fibrinogen-deficient patient confirming a GPVI/fibrin(ogen)interplay. Blocking fibrin polymerization by GPRP reduced the thrombin peak in normal PRP, in fibrinogen-supplemented PRP of the fibrinogen-deficient patient and in purified conditions. In contrast GPRP had no effect on the thrombin peak in normal PRP containing the Fab 9O12 and in the PRP of GPVI-deficient patients. The proof that GPVI specifically interacts with fibrin was obtained in a binding assay showing a dose-dependent binding of GPVI-Fc to fibrin polymers that was reversed by the Fab 9O12. Platelets adhered to polymerized fibrin resulting in platelet shape change and exposure of phosphatidylserine. Platelet adhesion on a fibrin network was observed at low (300 s-1) and high (1500 s-1) shear rates with the formation of small contractile thrombi. Adhesion was decreased by 62% for 9O12-treated platelets and by 43% with the blood of GPVI-deficient mice as compared to controls. Importantly, lack of GPVI or its blockade decreased stationary adhesion indicating that GPVI is required to stabilize the interactions between platelets and fibrin. Finally when hirudinated blood was perfused at a shear rate of 1500 s-1 onto preformed fibrin-rich clots, the Fab 9O12 decreased the recruitment of platelets by up to 93%.Conclusions: Here we show for the first time that GPVI acts as a receptor for polymerized fibrin with two major functions: GPVI interaction with polymerized fibrin triggers (i) a new loop amplifying thrombin generation and (ii) platelet recruitment at the clot surface. These, so far, unrecognized properties of GPVI confer it a key role in the maturation of the thrombus by facilitating its growth and stabilization in addition to its well-known effect in the initiation of thrombus formation. DisclosuresJandrot-Perrus:Acticor Biotech: Other. Gachet:Acticor Biotech: Other.

The small airways accordion: concurrent or alternating fluid absorption and secretion?

The small airways accordion: concurrent or alternating fluid absorption and secretion?

Generation of intense soft X-rays from capillary discharge plasmas

X-ray lasing through high voltage, high current discharges in gas filled capillaries has been demonstrated in several laboratories. This method gives highest number of X-ray photons per pulse. The fast varying current and the jxB magnetic force compress the plasma towards the axis forming a hot, dense, line plasma, wherein under appropriate discharge conditions lasing occurs. At Laser Plasma Division, RRCAT, a program on high voltage capillary discharge had been started. The system consists of a 400 kV Marx bank, water line capacitor, spark gap and capillary chamber. The initial results of the emission of intense short soft X-ray pulses (5–10ns) from the capillary discharge are reported.

Trimeric Autotransporter Adhesin-Dependent Adherence of Bartonella henselae, Bartonella quintana, and Yersinia enterocolitica to Matrix Components and Endothelial Cells under Static and Dynamic Flow Conditions

Trimeric autotransporter adhesins (TAAs) are important virulence factors of Gram-negative bacteria responsible for adherence to extracellular matrix (ECM) and host cells. Here, we analyzed three different TAAs (Bartonella adhesin A [BadA] of Bartonella henselae, variably expressed outer membrane proteins [Vomps] of Bartonella quintana, and Yersinia adhesin A [YadA] of Yersinia enterocolitica) for mediating bacterial adherence to ECM and endothelial cells. Using static (cell culture vials) and dynamic (capillary flow chambers) experimental settings, adherence of wild-type bacteria and of the respective TAA-negative strains was analyzed. Under static conditions, ECM adherence of B. henselae, B. quintana, and Y. enterocolitica was strongly dependent on the expression of their particular TAAs. YadA of Y. enterocolitica did not mediate bacterial binding to plasma or cellular fibronectin under either static or dynamic conditions. TAA-dependent host cell adherence appeared more significant under dynamic conditions although the total number of bound bacteria was diminished compared to the number under static conditions. Dynamic models expand the methodology to perform bacterial adherence experiments under more realistic, bloodstream-like conditions and allow dissection of the biological role of TAAs in ECM and host cell adherence under static and dynamic conditions.

Specific collection of adherent cells using laser release in a droplet-driven capillary cell

Laser pressure catapulting of adherent cells directly or cells grown on micropallets are two common methods of dislodgement. We describe a method where laser catapulting is performed as a flow is introduced orthogonally in a simple capillary chamber that is inexpensive and obviates flow-generating devices. The moving cells terminate near the contact line within the liquid medium, ensuring that they remain continuously hydrated and where the surface-tension forces hold them in place to permit a later collection process with a receptacle. By dislodging the cells close to the free edge of the liquid chamber, the amount of cell travel and, thus, contamination is minimized. The metrics of cell death and movement show that firing of the laser beam center a distance away from the cell to create a bubble that cavitates over time is more viable with the technique than directly on the cell.

The role of DNA diffusion in solid phase polymerase chain reaction with gel-immobilized primers in planar and capillary microarray format.

The solid phase polymerase chain reaction (PCR) on a gel-based microarray system was studied under various durations of individual stages of the PCR cycle and spatial restriction of the reaction volume. Combining the experimental study with numerical modeling, we demonstrated that the diffusion of the PCR product in and out of a microarray element during the annealing and melting stages, respectively, is the main factor responsible for distinctive features of the studied type of PCR. The restriction of reaction volume leads to faster PCR signal growth. Particularly, the capillary array, whereby gel-based microarray elements are located on a glass bar inserted into capillary chamber, was found to be a suitable format for the development of the platform.

Simple quantification of bacterial envelope-associated extracellular materials

We have developed a simple method for distinguishing between bacterial cultures that produce different amount of exopolysaccharide. It is based upon small differences in pellet volume formed by those cultures upon centrifugation. For that we have constructed a special centrifugation tube consisting of two connected chambers: an upper 12 ml chamber connected to a lower capillary chamber. Cells are applied to the upper chamber and following centrifugation, sink to its bottom and are forced into the capillary so that the height they fill can be measured. This procedure has been developed in order to demonstrate differences in volume of centrifugation pellet formed by similar number of Escherichia coli K12 wild type, rpoS mutant and yjbG rpoS double mutant cells. These differences are further shown to be a result of overproduction of colanic acid exopolysaccharide in the mutant strains. We suggest that this simple method can be employed to detect differences in other cell surface structures and to estimate biomass when optical density measurement or microscopic count is not applicable.

Delivery of apoptotic signal to rolling cancer cells: A novel biomimetic technique using immobilized TRAIL and E‐selectin

The survival rate for patients with metastases versus localized cancer is dramatically reduced, with most deaths being associated with the formation of secondary tumors. Circulating cancer cells interact with the endothelial lining of the vasculature via a series of adhesive interactions that facilitate tethering and firm adhesion of cancer cells in the initial steps of metastasis. TNF-related apoptosis-inducing ligand (TRAIL) holds promise as a tumor-specific cancer therapeutic, by inducing a death signal by apoptosis via the caspase pathway. In this study, we exploit this phenomenon to deliver a receptor-mediated apoptosis signal to leukemic cells adhesively rolling along a TRAIL and selectin-bearing surface. Results show that cancer cells exhibit selectin-mediated rolling in capillary flow chambers, and that the rolling velocities can be controlled by varying the selectin and selectin surface density and the applied shear stress. It was determined that a 1 h rolling exposure to a functionalized TRAIL and E-selectin surface was sufficient to kill 30% of captured cells compared to static conditions in which 4 h exposure was necessary to kill 30% of the cells. Thus, we conclude that rolling delivery is more effective than static exposure to a TRAIL immobilized surface. We have also verified that there is no significant effect of TRAIL on hematopoietic stem cells and other normal blood cells. This represents the first demonstration of a novel biomimetic method to capture metastatic cells from circulation and deliver an apoptotic signal.

An application of spatial deconvolution to a capillary‐based high‐pressure chamber for fluorescence microscopy imaging

Capillary-based high-pressure chambers for which the wall serves as both the optical window and mechanical support have been reported for fluorescence microscopy imaging. Although capillary chambers are straightforward and economical to construct, the curved capillary wall introduces image aberrations. The significance of these aberrations in imaging sub-cellular-dimension objects has yet to be assessed. Using a capillary chamber that is routinely pressurized to between 20 and 30 MPa, a pressure range suitable for studying a wide variety of cellular processes, we demonstrate sub-cellular-dimension spatial resolution in the imaging of fluorescent micro-spheres. Objectives with a range of numerical apertures (0.5-1.3) and working distances (0.1-7.4 mm) are considered. We show that spatial (or point-spread function, PSF) deconvolution improves image contrast in capillary-based images by comparing deconvolution results with those obtained from slide-mounted controls. Furthermore, similar deconvolution results between a measured PSF and a calculated, flat-geometry PSF indicate that the capillary wall is optically flat on cellular length scales. Results here facilitate the application of contemporary techniques in fluorescence microscopy to high-pressure imaging fields.

Fatal thrombosis in complex cardiac surgery without deep hypothermic circulatory arrest in the setting of standard-of-care heparinization: Status quo and directions for further research

Fatal thrombosis in complex cardiac surgery without deep hypothermic circulatory arrest was highlighted in a case report of biventricular assist device placement complicated by aortic cannula thrombosis and subsequent fatal cerebral infarction. The risk factors identified in this case were aprotinin exposure and stasis of blood in the aortic cannula after protamine administration. Despite standard-of-care heparinization, this syndrome has persisted, as evidenced by a series of case reports (n 4: 1996-2006). The purpose of this brief communication is to review this cumulative case series to guide further investigation. The literature search was conducted with PubMed (last entry May 31, 2007) with the following search terms: thrombosis and cardiac surgery; aprotinin and thrombosis in cardiac surgery; aminocaproic acid and thrombosis in cardiac surgery; tranexamic acid and thrombosis in cardiac surgery; and factor VIII and thrombosis in cardiac surgery. One case report was excluded inasmuch as it was later included as part of a larger case series. As a group, the published case reports of fatal thrombosis in complex cardiac surgery without deep hypothermic circulatory arrest can be summarized as follows: 1. The cohort total is 12 patients (7 men; 5 women). 2. The age range is 19 to 69 years. 3. All patients had antifibrinolytic therapy (11 aprotinin; 1 aminocaproic acid). 4. Anticoagulation was with bolus heparin titrated to maintain the activated clotting time (ACT) greater than 500 seconds (10 kaolin-based ACT; 1 celite-based ACT; 1 unspecified activator). 5. The type of complex cardiac surgery was as follows: valve replacement for infective endocarditis in 2 patients; ventricular assist device implantation in 6 patients; heart transplantation in 2 patients; and left ventricular reconstruction with a mitral valve procedure in 2 patients. 6. In 11 of 12 patients, circulatory collapse resulting from intravascular thrombosis began within 60 minutes of separation from cardiopulmonary bypass and protamine administration. In the remaining patient, gross thrombus was seen in the aortic cannula and ascending aorta within 60 minutes of protamine administration. 7. The circulatory collapse was in all cases severe, requiring reheparinization and return to cardiopulmonary bypass. The predominant hemodynamic pattern was right ventricular failure with acute pulmonary hypertension (10/11 cases). 8. The degree of thrombosis in all cases was clinically significant and all cardiovascular compartments were at risk: venous, arterial, capillary, and cardiac chambers. In 3 of 12 patients, the thrombus formation was evident on visual inspection. In 9 of 12, autopsy demonstrated diffuse microthrombi. 9. Fibrinolysis with tissue plasminogen activator was used as emergency rescue therapy in 2 patients. In 1 patient, this resulted in clinical improvement that allowed transfer to the intensive care unit. Unfortunately, this patient died subsequently of massive bleeding. 10. The syndrome has a 100% mortality. 11. In 1 patient, antibodies were detected that activated platelets via Fc-receptor IIa. In 11 of 12 patients, investigation for coagulation abnormalities was not reported. This case series is limited by the small sample size and suggests more questions than answers. Despite these limitations, the following observations may serve to direct future study of this fatal syndrome: 1. A global case registry would boost sample size and thus facilitate further analysis. 2. Preoperative hypercoagulable states may participate in the pathophysiology of the syndrome. 3. In the presence of an antifibrinolytic, standard-of-care heparinization for complex cardiac surgery in adults does not protect all patients from serious intraoperative thrombotic complications. 4. To date, this syndrome has not been reported in association with tranexamic acid or recombinant factor VIII. 5. When a case occurs, the index patient and family should be investigated for concomitant hypercoagulable states. Despite the advances in complex cardiac surgery without deep hypothermic circulatory arrest, there are still patients at risk for lethal vascular thrombosis. Further investigation is a priority to delineate the pathogenesis and effective therapy for this rare but important syndrome.

Studying dispersoid systems

Measurements of energy transformation in mitochondria are done on a capillary differential titration calorimeter CTD2156. It is important to mention that a sediment is quickly formed by the mitochondria suspension without mixing by means of a vibrating needle. During the measurements, the vibrating needle is located inside the working volume of the chamber. The design of the calorimeter is substantiated theoretically. It provides a new mode of a reagent input in the measuring volume of the calorimetric chambers. It expands the spectrum of tasks that can be solved using this instrument. In the capillary calorimeter the calorimetric chambers unit is simple and small in size. These advantages of capillary chambers provide an opportunity to unite 20 capillary calorimetric chambers in one calorimetric block. It allows designing a multi-channel titration calorimeter. There are obvious advantages of such a calorimeter over other instruments in screening researches and in researches of objects maintaining stability only for a short time.

Rapid Microvolume PCR of DNA Confirmed by Microchip Electrophoresis

PCR is an indispensable technique used in DNA analysis. However, with the traditional methods, the time spent on amplification and the subsequent analysis of PCR products is generally long. Therefore, it is essential to improve these two steps so that the whole procedure can be made faster. In the present work, with lambda-DNA as the control template, the amplification of 300-bp fragment could be completed within 37 s with capillary reaction chambers of LightCycler, and the following analysis of PCR products could be completed within 120 s with microchip electrophoresis as the detector. Since the high detection sensitivity of microchip electrophoresis, PCR products with template concentration as low as 5 fg/microL could be detected only after 435 s of amplification. In addition, based on additional optimized conditions simulated by CoventorWare, PCR microchips with distinct structure of the reaction chambers have been designed and successfully applied to the amplification of 300-bp fragment. By comparison, those chambers with ellipse and racket shapes were found to offer very high amplification efficiency. All of these results demonstrate the promise of integrating PCR and electrophoresis on microchip for developing easy-carrying instruments for the fast in situ detection of DNA.

12PREDICTION OF BULL FERTILITY BY COMPUTER ASSISTED SEMEN ANALYSIS

Sperm motility is clearly essential for fertilization both in vivo and in vitro. Motility is necessary for successful sperm transport, a step that is bypassed with in vitro fertilization. Recently, increasing attention has been paid to the objective evaluation and characterization of sperm motility more than simply determining the total proportion of motile spermatozoa. The purpose of computerassisted semen analysis (CASA) is to provide values for sperm concentration and sperm motility more rapidly and accurately than those obtained with traditional semen analyses methods. The objective of our experiment was to investigate the effect of specific aspects of sperm movement, such as the velocity of progression and the actual pattern of movement, to the fertilizing capability of sperm. Frozen semen samples of 10 HF breeding bulls were used in the study. For the motility analyses, Medealab CASA system (Medealab, Germany, Ver. 4.1) was used, and the velocity parameter of VCL (curvalinear velocity, μms−1), VSL (straight line velocity, μms−1), and VAP (average path velocity, μms−1) were evaluated and compared with the Day 30 and 75 non−return rates (NR30 and NR75). For every sample, a total of 10 fields were examined for 8s using a disposable 20 micron capillary chamber (CellVision, USA) giving a total of 1165 to 2831 cells evaluated. Chi square analysis, analyses of variance and linear correlation coefficient was applied to the statistical evaluation and comparison of the results. Data are based on weighted values. From the same batch of the analyzed frozen semen, a total of 8099 females were inseminated in more than 100 farms with a total of 6590 animals being positive for pregnancy at Day 30 and 4525 animals at Day 75. Within the bulls, differences were found in the values of NR30 and NR75 (P&amp;lt;0.05). Our data indicate very strong differences between the males’ NR30 and NR75 values (NR30: 65.6%±13.04 to 79.6%±11.17; P&amp;lt;0.001 and NR75: 37.8%±10.38 to 58.3%±15.53; P&amp;lt;0.001) reflecting the individual differences in the fertilizing capability of the males. All velocity parameters show very high correlation with strong significance both non−return rates but the best values belong to VAP (NR30 and NR75; P&amp;lt;0.02). Our data indicate that the bulls with lower VCL (25.51±33.04 to 79.54±58.03), VSL (11.35±19.45 to 36.36±35.71), and VAP (12.67±19.06 to 41.75±34.45) values showed lower fertilization rates both at NR30 and NR75. Computer and video technologies have advanced rapidly in recent years; thus the capability and accuracy of the latest versions of CASA systems are considerably better and they give more information about the different motion characteristics of spermatozoa. Because of the vital role of sperm motility in the reproductive process, such systems will enable us to move into a new era of diagnostic andrology and predict the fertilizing capability of semen. Supported by NKFP-Grants 4/040/2001 and 4/031/2001.

Secondary ionization of chemical warfare agent simulants: atmospheric pressure ion mobility time-of-flight mass spectrometry.

For the first time, the use of a traditional ionization source for ion mobility spectrometry (radioactive nickel ((63)Ni) beta emission ionization) and three alternative ionization sources (electrospray ionization (ESI), secondary electrospray ionization (SESI), and electrical discharge (corona) ionization (CI)) were employed with an atmospheric pressure ion mobility orthogonal reflector time-of-flight mass spectrometer (IM(tof)MS) to detect chemical warfare agent (CWA) simulants from both aqueous- and gas-phase samples. For liquid-phase samples, ESI was used as the sample introduction and ionization method. For the secondary ionization (SESI, CI, and traditional (63)Ni ionization) of vapor-phase samples, two modes of sample volatilization (heated capillary and thermal desorption chamber) were investigated. Simulant reference materials, which closely mimic the characteristic chemical structures of CWA as defined and described by Schedule 1, 2, or 3 of the Chemical Warfare Convention treaty verification, were used in this study. A mixture of four G/V-type nerve simulants (dimethyl methylphosphonate, pinacolyl methylphosphonate, diethyl phosphoramidate, and 2-(butylamino)ethanethiol) and one S-type vesicant simulant (2-chloroethyl ethyl sulfide) were found in each case (sample ionization and introduction methods) to be clearly resolved using the IM(tof)MS method. In many cases, reduced mobility constants (K(o)) were determined for the first time. Ion mobility drift times, flight times, relative signal intensities, and fragmentation product signatures for each of the CWA simulants are reported for each of the methods investigated.