Vacuum Source Research Articles

Electronic noise in optical homodyne tomography

The effect of the detector electronic noise in an optical homodyne tomography experiment is shown to be equivalent to an optical loss if the detector is calibrated by measuring the quadrature noise of the vacuum state. An explicit relation between the electronic noise level and the equivalent optical efficiency is obtained and confirmed in an experiment with a narrowband squeezed vacuum source operating at an atomic rubidium wavelength.

Characterization of Lipid A Acylation Patterns in Francisella tularensis, Francisella novicida, and Francisella philomiragia Using Multiple-Stage Mass Spectrometry and Matrix-Assisted Laser Desorption/Ionization on an Intermediate Vacuum Source Linear Ion Trap

Lipopolysaccharide (LPS) is a major component of the outer membrane of Gram-negative bacteria. The lipid A region of LPS stimulates the immune system in a structure-dependent manner. We have previously identified the two major lipid A species from Francisella tularensis as asymmetric tetraacylated structures containing four long acyl chains (16 and 18 carbons) and a single phosphate group that is partially modified by galactosamine (Phillips, N. J.; Schilling B.; McLendon, M. K.; Apicella, M. A.; Gibson, B. W. Infect. Immun. 2004, 72, 5340-5348). In the current study, we used matrix-assisted laser desorption/ionization on an intermediate vacuum source (vMALDI) coupled to a linear ion trap (LIT) mass spectrometer in multiple-stage mass fragmentation mode (MSn) to determine the structures of several minor and low abundant lipid A species present in F. tularensis, Francisella novicida, and Francisella philomiragia LPS that have not been previously characterized. Comprehensive vMALDI-MSn fragmentation studies allowed us to deduce the composition and the position of the fatty acid substituents within the lipid A moieties. Unexpectedly, most of these minor lipid A species consisted of multiple isobaric species with acyl chains of various lengths. Moreover, we found that a small portion of these lipid A species may be modified by the addition of a hexose or hexosamine sugar, in addition to the galactosamine that was previously identified. Overall, we found that MSn analysis on the vMALDI-LIT-MS platform was highly efficient and sensitive, allowing for thorough analysis of very minor lipid A species.

Theoretical and experimental study on the pressure and vacuum continuous control system based on hybrid pump

A novel pressure and vacuum continuous control system,which adopts a hybrid pump as pressure and vacuum source,is presented.The mathematical model of the system is developed.The theoretical simulation and analysis on the system are implemented in order to study the relationships among the characteristics,parameters and working points of the system.The experimental investigations on the system characteristics are presented with the adoption of a fuzzy-PID controller. The simulation and experimental results indicate that the pressure and vacuum continuous control system based on hybrid pump has good dynamic and static performance,strong robustness and satisfactory adaptability to various system parameters.According to the results,system can successfully gain high accuracy and fast response signal.Also,the mathematical model of system is also testified by the experimental results.

The Motogenic Effects of Cyclic Mechanical Strain on Intestinal Epithelial Monolayer Wound Closure Are Matrix Dependent

Complex deformation during normal digestion due to peristalsis or villous motility may be trophic for the intestinal mucosa. Because tissue fibronectin is increased in inflammatory states that may accompany mucosal injury, we evaluated the effects of cyclic mechanical strain and fibronectin on intestinal epithelial monolayer wound closure in Caco-2 and IEC-6 intestinal epithelial cells. Wounds created in intestinal epithelial monolayers were subjected to cyclic deformation. Wound closure was assessed by morphometry using microscopic imaging. Cell signals were assessed by Western blot and confocal microscopy. Mechanical strain stimulated wound closure on fibronectin but inhibited closure on collagen in Caco-2 and IEC-6 cells. The effect was independent of proliferation or cell spreading. Myosin light chain (MLC) and extracellular signal-regulated kinase (ERK) were phosphorylated in response to strain in confluent monolayers on both collagen and fibronectin. Blocking MLC or ERK phosphorylation inhibited the motogenic effect of strain on fibronectin. Although phosphorylated MLC was redistributed to the leading edge of migrating cells following 6 hours of strain on collagen and fibronectin, phosphorylated ERK was redistributed to the lamellipodial edge only on fibronectin. Strain promotes intestinal epithelial wound closure by a pathway requiring ERK and MLC kinase. Fibronectin-dependent ERK redistribution in response to strain in confluent migrating cells may explain the matrix dependence of the motogenic effect. Repetitive deformation stimulates intestinal epithelial proliferation on a collagen substrate, but not fibronectin. Deformation may exert matrix-dependent effects on intestinal epithelial cells, promoting epithelial restitution in fibronectin-rich tissue and proliferation in fibronectin-poor mucosa.

The Mucus Slurper: a novel tracheal tube that requires no tracheal tube suctioning. A preliminary report

The buildup of mucus within the endotracheal tube (ETT) progressively reduces its internal volume. We devised the Mucus Slurper as an integral part of the tracheal tube to aspirate all mucus automatically at its distal tip. In vitro, and in vivo studies in sheep at the National Institutes of Health, NHLBI, PCCMB. Six sheep, sedated, paralyzed, and mechanically ventilated We evaluated the Mucus Slurper in vitro, and we evaluated its efficacy and safety in three healthy sheep during 24 h on volume-controlled mechanical ventilation in comparison to three sheep managed with open tracheal tube suctioning. In vitro: with the Mucus Slurper connected to a source of vacuum of 450-500 mmHg the total volume of a single suction lasting 0.1, 0.2, and 0.3 s was, respectively, 75.4 +/- 7.9, 114.5 +/- 4.6, and 143.4 +/- 8.7 ml; with the measured vacuum within the lumen of the Mucus Slurper ring of 37 cmH2O. In vivo: during mechanical ventilation we aspirated through the Mucus Slurper 13.4 +/- 3.3 cc mucus/24 h. During the course of single aspiration the Mucus Slurper never affected the level of applied PEEP. The tracheal tube was free of tracheal secretions in the Mucus Slurper group while thin secretions were found within the ETT in the control group. The Mucus Slurper is a novel device designed to keep the tracheal tube and proximal trachea free of mucus. In studies in sheep lasting 24 h the Mucus Slurper was safe and prevented all mucus accumulation within the ETT.

Pigtail Catheters Used for Percutaneous Fluid Drainage: Comparison of Performance Characteristics

To compare the performance characteristics of various single-lumen all-purpose pigtail drainage catheters. The following parameters were compared: flow rates between catheters of the same size, whether changing the fluid viscosity has any effect on catheter comparisons, the effect on flow of leaving an open three-way stopcock in the drainage pathway, the tendency of the catheters to kink, and catheter patency after kinking, as measured according to flow. All-purpose 8.0-, 8.3-, and 8.5-F (collectively referred to as 8-F); 10.0-, 10.2-, and 10.3-F (collectively referred to as 10-F); and 12.0-F pigtail drainage catheters from three manufacturers were evaluated. Data were compared by using two-tailed t tests after normal distributions were confirmed. P < .05 was considered to represent a significant difference. At comparison of the 8-F catheters, the C.R. Bard catheters demonstrated better flow rates than the Cook and Boston Scientific devices. Among the 10-F catheters, there were no significant differences in the flow rates of fluid with viscosity equivalent to that of water between the C.R. Bard and Boston Scientific catheters; however, both these catheter types demonstrated significantly (P < .05) better flow rates than the Cook devices. Among the 12-F catheters, the C.R. Bard catheters demonstrated significantly (P < .05) better flow rates than the other two catheter types. Changing the fluid viscosity caused no changes in comparison results. In all catheter groups, the presence of a stopcock significantly (P < .05) impaired flow. None of the evaluated catheters demonstrated a clear advantage in terms of patency or susceptibility to kinking. At comparison of the in vitro performances of catheters from different manufacturers, the C.R. Bard 8.0-F and Cook 10.2-F catheters had comparable flow rates, and flow rates through the C.R. Bard and Boston Scientific 10.0-F catheters were comparable to flow rates through the Cook and Boston Scientific 12.0-F catheters. Varying viscosity had no effect on comparisons of catheter flow rates; however, a stopcock between the vacuum source and the catheter was noted to impair flow rates in all brands and sizes of evaluated catheters.

Surgical Wound Case Studies With the Versatile 1 Wound Vacuum System for Negative Pressure Wound Therapy

Negative pressure wound therapy consists of a wound dressing, a drainage tube inserted into the dressing, an occlusive transparent film, and a connection to a vacuum source that supplies the negative pressure. A new product called the Versatile 1 Wound Vacuum System (BlueSky Medical, La Costa, Calif) is available for negative pressure wound therapy. This article describes the application, management, and effectiveness of the Versatile 1 in 3 cases where the patients have all undergone surgical debridement.

Mixing with bubbles: a practical technology for use with portable microfluidic devices

This paper demonstrates a methodology for micromixing that is sufficiently simple that it can be used in portable microfluidic devices. It illustrates the use of the micromixer by incorporating it into an elementary, portable microfluidic system that includes sample introduction, sample filtration, and valving. This system has the following characteristics: (i) it is powered with a single hand-operated source of vacuum, (ii) it allows samples to be loaded easily by depositing them into prefabricated wells, (iii) the samples are filtered in situ to prevent clogging of the microchannels, (iv) the structure of the channels ensure mixing of the laminar streams by interaction with bubbles of gas introduced into the channels, (v) the device is prepared in a single-step soft-lithographic process, and (vi) the device can be prepared to be resistant to the adsorption of proteins, and can be used with or without surface-active agents.

Bench-Top Evaluation of Air Flow through a Valved Peelable Introducer Sheath

Air embolism is a rare but potentially fatal complication that may occur during the insertion of a central venous catheter. A valved peelable introducer sheath was developed to reduce the likelihood of an air embolus. This study was performed to determine the rate of air flow through this valved introducer sheath under different conditions that may be encountered in a clinical setting. A 16-F-diameter valved peelable introducer sheath was used for all experiments. A bench-top testing system was constructed that consisted of a vacuum source, a mass flow meter, and a digital vacuum gauge. A coupling device with a pneumatic O-ring was used to seal and connect the distal end of the introducer sheath to the testing system. A vacuum of -5 mm Hg was applied to the sealed distal end of the sheath to simulate physiologic conditions. The rate of air flow through the valved sheath was measured under three different conditions; (i) valve open, (ii) valve closed, and (iii) valve open but with the sheath manually pinched. Thirty air flow measurements were performed for each of the three test conditions. When the valve was in the open position, the mean rate of air flow through the introducer sheath was 417.2 mL/sec (range, 415.5-419.7 mL/sec). When the valve was in the closed position, the mean rate of air flow was 0.004 mL/sec (range, 0.000-0.067 mL/sec). When the valve was open but the sheath was manually pinched, the mean rate of air flow through the sheath was 31.7 mL/sec (range, 23.0-38.8 mL/sec). During the 90 testing procedures, the mean vacuum was -5.10 mm Hg (range, -5.00 to -5.45 mm Hg). This bench-top study revealed that a massive amount of air flowed through the open 16-F introducer sheath when it was subjected to a vacuum of -5 mm Hg, a situation that may occur under normal physiologic conditions. The rate of air flow could be decreased by aggressively pinching the sheath but the rate of air flow was still substantial. This study demonstrated that the addition of a sophisticated valve mechanism can essentially eliminate air flow through a peelable introducer sheath.

Subjective predictors of pain in women undergoing electrical vacuum aspiration versus those undergoing manual vacuum aspiration for first-trimester abortion

Introduction: There are limited prospective data exploring patients' pain and predictors of procedure-related pain in women undergoing electrical vacuum aspiration (EVA) or manual vacuum aspiration (MVA). This study explores patients' experience with pain during either EVA or MVA. Materials and Methods: In this randomized clinical trial, women presenting for surgical abortion were recruited from three sites. Eligibility criteria included an intrauterine pregnancy of less than 11 weeks, age of 18 years or older and good health. Subjects were randomly assigned to undergo either EVA or MVA. The procedural technique was standardized across centers. Participants completed questionnaires including visual analogue scales for pain. Logistic regression was used to analyze the data. Results: There were no sociodemographic or reproductive health differences between groups (EVA=63; MVA=64). The mean age of the patients was 25 years. Non-White women were more likely to report pain (OR, 3.1; 95% CI, 1.0���9.7). There was no significant difference in pain scores between groups (OR, 0.62; 95% CI, 0.27���1.44). Predictors of pain included patients' preoperative anticipation of pain (OR, 2.84; 95% CI, 1.1���7.6) and fear of bleeding (OR, 4.8; 95% CI, 1.46���15.6). Compared with women who were neutral about pelvic examinations, those who reported no fear of pelvic examinations were less likely to report pain during the procedure (OR, 0.31; 95% CI, 0.11���0.92). Patients reporting increased intraoperative anxiety were more likely to report increased intraoperative pain (OR, 6.1; 95% CI, 2.4���15.4). In multivariate analysis, both fear of bleeding (OR, 4.5; 95% CI, 1.0���20.2) and anxiety during the procedure (OR, 4.4; 95% CI, 1.7���11.7) strongly predicted procedure-associated pain. Discussion: The source of vacuum does not appear to predict pain during first-trimester abortion. Conclusion: Counseling and a supportive environment perioperatively may help alleviate anxiety about a procedure, thus decreasing pain perception.

Intrathoracic Pressure Regulator During Continuous-Chest-Compression Advanced Cardiac Resuscitation Improves Vital Organ Perfusion Pressures in a Porcine Model of Cardiac Arrest

A novel device, the intrathoracic pressure regulator (ITPR), combines an inspiratory impedance threshold device (ITD) with a vacuum source for the generation of controlled -10 mm Hg vacuum in the trachea during cardiopulmonary resuscitation (CPR) while allowing positive pressure ventilation. Compared with standard (STD) CPR, ITPR-CPR will enhance venous return, systemic arterial pressure, and vital organ perfusion in both porcine models of ventricular fibrillation and hypovolemic cardiac arrest. In protocol 1, 20 pigs (weight, 30+/-0.5 kg) were randomized to STD-CPR or ITPR-CPR. After 8 minutes of untreated ventricular fibrillation, CPR was performed for 6 minutes at 100 compressions per minute and positive pressure ventilation (100% O2) with a compression-to-ventilation ratio of 15:2. In protocol 2, 6 animals were bled 50% of their blood volume. After 4 minutes of untreated ventricular fibrillation, interventions were performed for 2 minutes with STD-CPR and 2 minutes of ITPR-CPR. This sequence was repeated. In protocol 3, 6 animals after 8 minutes of untreated VF were treated with ITPR-CPR for 15 minutes, and arterial and venous blood gases were collected at baseline and minutes 5, 10, and 15 of CPR. A newer, leak-proof ITPR device was used. Aortic, right atrial, endotracheal pressure, intracranial pressure, and end-tidal CO2 values were measured (mm Hg); common carotid arterial flow also was measured (mL/min). Coronary perfusion pressure (diastolic; aortic minus right atrial pressure) and cerebral perfusion pressure (mean arterial minus mean intracranial pressure) were calculated. Unpaired Student t test and Friedman's repeated-measures ANOVA of ranks were used in protocols 1 and 3. A 2-tailed Wilcoxon signed-rank test was used for analysis in protocol 2. Fischer's exact test was used for survival. Significance was set at P<0.05. Vital organ perfusion pressures and end-tidal CO2 were significantly improved with ITPR-CPR in both protocols. In protocol 1, 1-hour survival was 100% with ITPR-CPR and 10% with STD-CPR (P=0.001). Arterial blood pH was significantly lower and Paco2 was significantly higher with ITPR-CPR in protocol 1. Arterial oxygen saturation was 100% throughout the study in both protocols. Paco2 and Pao2 remained stable, but metabolic acidosis progressed, as expected, throughout the 15 minutes of CPR in protocol 3. Compared with STD-CPR, use of ITPR-CPR improved hemodynamics and short-term survival rates after cardiac arrest.

Letter To The Editor: New Digital Video Intubation Device

Digital video intubation is leading the way into a refreshing trend to change traditional endotracheal intubation and bring 21 century low cost, hand held digital technology to the medical emergency field. The RES-Q-SCOPE(R) is one of the first products to address well known issues plaguing endotracheal intubation for many years and drastically simplify the procedure. The RES-Q-SCOPE ® (http://www.res-q-tech-na.com for full details and video) may be considered essential in combat and mass casualties, for paramedics, first responders teams and in the emergency rooms. The state of the art hand held FIELD VIDEO LARYNGOSCOPE is self contained and uses a rechargeable power source. It features a pre-loaded standard 6-8.5mm Endotracheal Tube with disposability advantages enabling rapid serial intubations in the field and rapid establishment of an airway. The RES-Q-SCOPE ® is a patented and FDA registered, multifunction field video laryngoscope, which uses cutting edge digital image technology featuring a 2.75”color LCD screen to externally visualize the intubation process in the field. The RES-Q-SCOPE ® requires modest training to slide the device into position to visualize the epiglottis with little effort. There should be minimal need, if any, to reposition the C-spine in case of suspected neck injury. Furthermore, the RES-Q-SCOPE ® itself features a channel where a standard endotracheal tube can be easily pre-loaded into the device. A light source for external visualization of the intubation process, as the endotracheal tube passes into the trachea. The process can be seen through a small color LCD screen, which has the ability to adopt multiple positions, so that the practitioner can be located at the side of the patient or at multiple other positions around the patient. A vacuum source can be attached to an external adapter provided, to assist clearing fluids that may be present in the throat. The same channel can be reversibly, used to provide oxygen if needed. A disposable unit can be easily detached and discarded. Multiple clean intubations may be performed in the field by simply attaching a new disposable unit, thus allowing for serial intubation of multiple patients in a disaster theater or emergency scene. The RES-Q-SCOPE ® is powered with a rechargeable long duration battery, also allowing for serial intubations when needed. An additional and emergency dry cell pack is also available using 4 AA's to use under extreme conditions such as the battlefield. The RES-Q-SCOPE ® is a product designed to improve the chances of saving a life in a respiratory emergency where it occurs. It is considered essential in disaster preparation and emergency response of all kinds including combat emergencies. Complete information and description and video, can be obtained by visiting http://www.res-q-tech-na.com and watch a video of a conscious intubation under LCD screen visualization. This technology is readily available at an extremely low cost (whole kit for around $400-$500).

Liquid supports for ultraviolet atmospheric pressure matrix-assisted laser desorption/ionization.

Atmospheric pressure (AP) liquid matrices for ultraviolet (UV) matrix-assisted laser desorption/ionization (MALDI) are presented. Doping a known organic chromophore, alpha-cyano-4-hydroxycinnamic acid (CHCA), into liquid media yielded a homogenous sample system with simplified sample preparation, increased sample lifetime, and added utility for APMALDI ion sources. Compared with vacuum situations, AP matrices are not as limited by vapor pressure, so liquid matrix formulations can focus on desorption and ionization versus vacuum stability and source contamination. The parameters studied include chromophore concentration, liquid support variations, and quantitation capability. Chromophore concentration adjustments provided insight into the necessary absorbance for UV-APMALDI and demonstrated the importance of laser penetration depth. Liquid support variations allowed adjustments of sample lifetime and analyte solvents. Extended sample lifetime is beneficial for instrument tuning and source optimization; however, increased liquid viscosity lowers signal intensity. The shot-to-shot reproducibility, as examined with individual ion packets, suggests that the liquid matrix can alleviate some inconsistencies seen with solid MALDI, suggesting a possibility for better quantitation. The measurements for laser penetration depth, solution viscosity, and solvent additives could add to the information on MALDI mechanisms. The liquid matrix offers advantages that complement current MALDI methods.

Automobile maintenace: Meters and gauges to PCs

A utomobiles, at the beginning of the 20th century, had little more than a radiator mounted, alco- hol-filled thermometer and a crude speed- ometer. Magneto ignition was usually the extent of the electrical system. Regularly scheduled vehicle maintenance of- ten required disassem- bly and reassembly in an owner's barn or at re- tually a rheostat-driven fuel gauge, an electric temperature gauge, a zero-cen- tered ammeter, and an oil pressure gauge rounded out the gauge cluster. Vacuum-powered windshield wip- ers replaced hand-operated ones dur- ing this time. The intake manifold provided the vacuum source. Engine speed and throttle position governed manifold pressure, which was affected by engine internal wear. The wiper speed varied with engine speed and throttle position; wipers slowed during idle and aggressive acceleration. Many people relied on the operation of the wipers as an indicator of the internal engine condition. Mechanics used dipsticks to monitor engine condition, watching the oil's color, temperature, and odor for particles from metal wear and carbon from engine oil coking. Some mechanics even used taste to guess internal engine condition. During this period, performance, re- liability, and simplicity in operation greatly improved when distributor ig- nition replaced magneto ignition. The 6-V flooded cell storage battery and dc generator enabled the dc starter motor, which ended the hand-crank era. Elec- tric lamps replaced acetylene and kero- sene exterior lamps. Tube radios, with their unreliable vibrators producing quasi ac, became common. Zero-cen- tered ammeters were limited to indicat- ing current flow to or from a battery. Electro-mechanical current and voltage regulators often caused surprise dead batteries and electrolysis, contrib- uting to low electrolyte level and buildup of insulating lead sulfate on battery terminals. Modern Automobile Emerges

A DISPOSABLE SELF-PRIMING AND BUBBLE TOLERANCE PNEUMATIC ACTUATION MICRO-PUMP

International Journal of Computational Engineering ScienceVol. 04, No. 02, pp. 253-256 (2003) BioMEMS and MicrofluidsNo AccessA DISPOSABLE SELF-PRIMING AND BUBBLE TOLERANCE PNEUMATIC ACTUATION MICRO-PUMPGUOLIN XU, DOR NGI TING, VINCENT LUAR, and LIN KIAT SAWGUOLIN XUInstitute of Bioengineering and Nanotechnology, 51 Science Park Road, The Aries, Singapore 117586, Singapore Search for more papers by this author , DOR NGI TINGInstitute of Bioengineering and Nanotechnology, 51 Science Park Road, The Aries, Singapore 117586, Singapore Search for more papers by this author , VINCENT LUARInstitute of Bioengineering and Nanotechnology, 51 Science Park Road, The Aries, Singapore 117586, SingaporeNational University of Singapore, Singapore Search for more papers by this author , and LIN KIAT SAWInstitute of Bioengineering and Nanotechnology, 51 Science Park Road, The Aries, Singapore 117586, Singapore Search for more papers by this author https://doi.org/10.1142/S1465876303001010Cited by:2 PreviousNext AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsRecommend to Library ShareShare onFacebookTwitterLinked InRedditEmail AbstractA low cost, robust, self-priming and bubble tolerance pneumatically actuated planar micro-pump was demonstrated and characterized. This micro-pump has a simple three-layered structure. The two micro-pump housings were fabricated with polycarbonate, while the actuation membrane which, also acted as the inlet and outlet valves was made form polydimethylsiloxane(PDMS). PDMS displayed desirable mechanical properties including very low Young's modulus, high elongation, biocompatibility and good sealing for the design of this micropump. The use of PDMS as actuation memberanes solved problems of sealing and poor compression ratio associated with most silicon based micro-pumps. Furthermore, polycarbonate material is much easier and cheaper to fabricate than silicon wafer. Using external compressed air and vacuum source for atuation, flow rate near to 1000ul/min of air or liquid has been achieved. The maximum pump head of more than 2m is obtained with water as pumping media. The pump exhibited a linear output flow rate, insensitive to output pressure.Keywords:micro-fluidicmicro-pumpmicro-valvePDMS References Disier Maillefer, Stephan Gamper, Beatrice Frehner, Patrick Balmer. "A High performane Silicon micro-pump for an implantable drug delivery system" MEMS 1999, Orlando, Florida . Google Scholar R. Linnemann, P. Woias, C. D. Senfft, and J. A. Ditterich, " A self-priming and bubble tolerant piezoelectric silicon micro-pump for liquids and gases". The 11th annual international workshop on MEMS. 1998, Heidelberg German, pp. 532-5371 . Google Scholar Hou-Pu Chou, Marc A. Unger, Axel Scherer and Stephen R. Quake "Integrated elastomer fluidic lab-on-a-chip surface patterning and DNA diagnostic" . Google ScholarM. Richter, R. Linnemann and P. Woias, Sensors and Actuators A68, 480 (1998). Google Scholar FiguresReferencesRelatedDetailsCited By 2A pneumatic PDMS micropump with in-plane check valves for disposable microfluidic systemsJunhui Ni, Beizhi Li and Jianguo Yang1 Nov 2012 | Microelectronic Engineering, Vol. 99A planar PDMS micropump using in-contact minimized-leakage check valvesJunhui Ni, Fengliang Huang, Bin Wang, Beizhi Li and Qiao Lin27 August 2010 | Journal of Micromechanics and Microengineering, Vol. 20, No. 9 Recommended Vol. 04, No. 02 Metrics History Keywordsmicro-fluidicmicro-pumpmicro-valvePDMSPDF download

Rh-prophylaxis in early abortion

Rh-prophylaxis in early abortion

The Use of a Uniquely Designed Anesthetic Scavenging Hood to Reduce Operating Room Anesthetic Gas Contamination During General Anesthesia

Numerous studies have suggested that chronic exposure to trace levels of anesthetic gas is harmful to operating room (OR) personnel. In the delivery of pediatric general anesthesia, an uncuffed endotracheal tube (ETT) is normally used which can result in considerable volatile anesthetic and nitrous oxide contamination of the OR. In this report, we present a method to reduce exposure to these anesthetic gases by means of an anesthetic scavenging hood (ASH). The ASH was used on six pediatric patients undergoing general endotracheal anesthesia via an uncuffed ETT. Measurements of all ambient gas levels were made 6 in. horizontally from the patient’s ear and 6 in. from the table surface. The application of the vacuum source to the ASH resulted in a very significant (P < 0.01, paired t-test) decrease in levels of ambient anesthetic gas, with no measurable change in ventilatory variables or changes in body temperature (P > 0.05, paired t-test). Discontinuation of the vacuum force to the ASH resulted in a marked increase in ambient levels of anesthetic gas. We conclude that the ASH is extremely effective in reducing waste anesthetic gas associated with anesthesia administered via an uncuffed ETT. The ASH may be a valuable and cost-effective addition in the OR for both reducing ambient anesthetic waste gas levels and conserving patient heat.

A simple and rapid technique for assaying toxicants in aphids

A simple bioassay technique has been developed in order to study the effect of toxic compounds on aphids. The technique involves dipping of leaves of a particular aphid host in a solution of the desired toxic compound contained in a vacuum flask. The flask is then connected to a vacuum source in order to remove the air from the intercellular spaces of the palisade and the spongy parenchymas of the leaves. Breakage of the vacuum and return to atmospheric pressure forces the test solution into the now empty intercellular spaces which are thus filled with the solution. The treated leaves exhibited a typical water‐soaked appearance. The infiltrated leaves were then offered to the aphids. The above treatment did not affect either the structure of the leaves or the development of the aphid colony on them. Aphids grown on leaves infiltrated with water lived longer in comparison with controls. In addition, insects grown on leaves infiltrated with 27.5, 13.7 and 6.9 p.p.m. of the systemic insecticide heptenophos died after 1.5, 3.0 and 5.0 h, respectively. The bioassay technique described in this report has certain advantages: it is simple, fast and inexpensive and is especially suitable for short‐term studies involving the effects of such chemicals as toxins, insecticides and other toxicants on aphids. It may also be used to study the effects of growth factors, hormones and special nutrients on aphid growth and possibly on other sucking insects.

Assessing Passive Capillary‐Wick Samplers for monitoring resident nitrate concentration in real field

Abstract. We evaluated the effectiveness of capillary‐wick samplers (PCAPS) for continuous monitoring of resident nitrate concentration in three ‘soil‐crop‐climate’ systems differing in soil type, land use and climate. These systems involved: (i) acid silty soils under a beech‐oak forest affected by heavy N‐NH4+ deposition in Belgium; (ii) silty soils under wheat cropping and a short rotation willow coppice plantation (SRC) in Belgium; and (iii) volcanic ash soils under plantain cultivation with and without urea fertilization in Colombia. The PCAPS continuously applied a suction of 0 to 5.4 kPa to the soil water below the effective rooting zone without the need for an auxiliary vacuum source. The nitrate concentrations showed large variations over time and ranged between 6–192 mg l–1 under forest, 19–143 mg l–1 under wheat, 11–47 mg l–1 under SRC and 3–138 mg l–1 under fertilized plantain. The analysis of the soil leachates collected with PCAPS confirms previous results dealing with leaching of nitrate and alkaline and alkaline‐earth cations in similar ‘soil‐crop‐climate’ systems. It was concluded that PCAPS was a suitable tool to collect soil solutions and that it could help to assess nitrate leaching losses in various ecological or cropping conditions.

First trimester surgical abortion practices: a survey of National Abortion Federation members

The objective of this study was to survey first trimester surgical abortion practices of North American providers. A survey was mailed to the 310 active member clinics of the National Abortion Federation, the professional organization of abortion providers in North America. The 236 respondents (76%) comprising the study group provided approximately 30% and 33% of all first trimester abortions in the US and Canada, respectively. Of the 529 practitioners who perform most abortions at the clinics, 68% are obstetrician-gynecologists, and 18% are family physicians; 51% are at least 50 years old. The majority of respondents (156 of 236, 66%) confirm gestational age with ultrasonography. Of the 202 clinics that favor one method of anesthesia, 58% use local cervical block with or without oral pre-medication, 32% combine local anesthesia with intravenous sedation, and 10% use general anesthesia. Most clinics open the cervix with tapered dilators (207 of 233, 89%), evacuate the uterus by using curved rigid plastic cannulas (157 of 229, 69%) and an electric vacuum source (191 of 233, 82%), and explore the uterus with a metal curette following aspiration (133 of 232, 57%). A large majority of respondents examine the uterine aspirate on-site (91%), prescribe antibiotics (91%), and offer oral contraceptives (95%) when requested. Although variations exist, surgical techniques and postoperative practices are quite uniform among clinics. Local anesthesia is presently the most frequent method of pain control. Ultrasonographic dating before abortion is common practice. The “graying” of skilled practitioners raises concerns about the future availability of abortion.