Venturi Pump Research Articles

Exploration of micro-miniature venturi pump for continuous glucose monitoring through interstitial fluid (ISF) extraction

Interstitial Fluid (ISF) is a naturally occurring body fluid that surrounds cells and tissues and contains certain markers useful for continuously monitoring glucose levels in the blood without constantly extracting it. Miniaturizing can reduce its cost and timescale. In this study, for continuous glucose monitoring the numerical analysis of a Polymethyl methacrylate (PMMA) based Micro-miniature venturi pump was carried out to extract Interstitial Fluid (ISF). The numerical study was carried out using COMSOL Multiphysics software by employing the k-ε turbulence model to obtain output as a vacuum at the throat of the pump. The micro-miniature venturi pump was numerically analyzed for several key parameters, including the dimensions of the throat, the convergent angle, and the divergent angle. This study obtained a minimum pressure of 49.41 kPa numerically and 70 kPa experimentally when an input pressure of 252 kPa of compressed air was given to the system. Further influence of turbulence kinetic energy and turbulence dissipation rate on throat pressure output have been notified. Notably, the pressure output reaches its minimum value of 49.41 kPa when the turbulent kinetic energy and the turbulent dissipation rate reach maximum values of 5.0 × 109 m2/s3 and 7000 m2/s2 respectively. As per the previous research findings, for continuous glucose monitoring through ISF extraction, a pressure level of 95 kPa is deemed adequate hence the designed micro-miniature venturi pump is suitable for this application.

A comparison of venturi and peristaltic based phacoemulsification efficiency in routine femtosecond laser cataract surgery

OBJECTIVETo compare the efficiency of venturi and peristaltic pump phacoemulsification systems in patients undergoing routine laser cataract surgery. DESIGNSingle center, non-randomized clinical study. PARTICIPANTSThe study compared consecutive eyes with moderate nuclear sclerosis undergoing routine laser cataract surgery at the Outpatient Eye Center, Mercy Health System, Springfield, MO, USA. METHODSEach surgery utilized the same femtosecond laser settings. Surgeries were performed with either a venturi or peristaltic vacuum system by a single surgeon (WJS). The EFX, percent power, ultrasound time (UST), the total time that the phaco tip was in the eye (phaco tip in/out time, PIOT) and the surgery time (speculum in/out time) were recorded. Exclusions and intraoperative complications were also analyzed. RESULTS995 eyes were included in the study. The EFX in the venturi eyes (1.7±1.3; n=521) compared to peristaltic eyes (2.1±1.4; n=474) was lower (p <0.0001). Similarly, the UST in the eyes performed with the venturi system versus the peristaltic system was reduced (32.4±22.3 sec vs. 40.7± 25.7 sec; p <0.0001). The PIOT in the venturi group compared to the peristaltic group was less (71.1±31.1 sec vs. 79.1±36.1 sec; p = 0.0002). The case time (speculum in/out time) was lower for the venturi eyes (307.2±68.8 sec vs. 311.6±53.6 sec; p=0.268). CONCLUSIONIn eyes undergoing routine laser cataract surgery, use of the venturi pump system was more efficient compared to peristaltic pump system based on energy use and time, and there was no significant difference in complications.

Efficient use of ultrasound in cataract surgery.

Modern phacoemulsification machines apply ultrasound through a variety of settings and parameters to remove a cataract. Using these new technologies efficiently is critical for both reducing surgical times and improving postoperative outcomes. The present article reviews recent findings in phacodynamics to explore the optimum use of ultrasound in cataract surgery. In studies seeking to determine the optimum parameters in both fluidics and power, increased power and aspiration does not necessarily equate to more efficiency. New developments, such as torsional ultrasound, micropulse, and burst mode have shown increased efficiency in randomized control trials and in-vitro compared with conventional ultrasound. Regarding vacuums, the venturi pump has demonstrated greater efficiency compared with the peristaltic pump. We also explore other parameters, such as chamber pressure and tip selection. Meta-analyses on femtosecond-laser assisted cataract surgery (FLACS) have shown similar long-term visual outcomes compared to conventional cataract surgery. Though conventional cataract surgery remains highly effective, surgeons have increasing options for customizing their ultrasound settings and phacoemulsification techniques.

Utility of low-cost, miniaturized peristaltic and Venturi pumps in droplet microfluidics

Many laboratory applications utilizing droplet microfluidics rely on precision syringe pumps for flow generation. In this study, the use of an open-source peristaltic pump primarily composed of 3D printed parts and a low-cost commercial Venturi pump are explored for their use as an alternative to syringe pumps for droplet microfluidics. Both devices provided stable flow (<2% RSD) over a range of 1–7 μL/min and high reproducibility in signal intensity at a droplet generation rate around 0.25 Hz (<3% RSD), which are comparable in performance to similar measurements on standard syringe pumps. As a novel flow generation source for microfluidic applications, the use of the miniaturized Venturi pump was also applied to droplet signal monitoring studies used to measure changes in concentration over time, with average signal reproducibility <4% RSD for both single-stream fluorometric and reagent addition colorimetric applications. These low-cost flow methods provide stable flow sufficient for common droplet microfluidic approaches and can be implemented in a wide variety of simple, and potentially portable, analytical measurement devices.

Adult sea lamprey respond to induced turbulence in a low current system

Manipulation of water velocities and turbulence using pumps, propellers, or jets is a promising alternative to physical water control structures to guide fish towards traps or fishways. Sea lamprey (Petromyzon marinus) are a species of concern in much of their native and invasive ranges, and their improved guidance could benefit management actions for both conservation and control. The flow velocity enhancement system (FVES), an emergent technology that uses a Venturi pump to generate a plume of turbulence, has shown promise guiding downstream migrating fish in slow-moving or static water conditions formed by large reservoirs, but is untested for guidance of upstream swimming fish in low current environments. The FVES had minimal impact on depth averaged velocity profiles, but produced elevated levels of turbulence. Changes in spatial distribution and number of turns suggest sea lamprey detect and are mildly attracted to turbulence induced by the FVES. These results demonstrate the potential of induced turbulence as a guidance mechanism for upstream migrating sea lamprey, but more extensive testing is needed to show the full utility of this approach.

Testing a Novel Device for Accurate Ultrasound Delivery During Crystalline Lens Phacoemulsification Surgery.

PurposeTo assess whether the use of a patented, novel feedback device intended to accurately control phacoemulsification tip elongation is effective under varying machine settings and material resistance.MethodsSculpt mode phaco (550-mm Hg Venturi pump; elongations, 35 and 70 µm) and quadrant settings (550-mm Hg Venturi pump; elongations, 15, 30, and 60 µm) were used in agar gel of incremental density (1%, 2%, 3%, and 6% in demineralized water). Dispersed lens fragments were also simulated with 6% agar gel spherules (2–5 mm in diameter; 550-mm Hg vacuum, and 60-µm elongation). Actual phaco tip elongation was measured on voltage readings from the piezoelectric crystals and compared to nominal elongation with feedback control off and on.ResultsMismatch between nominal and actual elongation when feedback control was off in sculpt mode varied between –13.51 µm and –23.07 µm of nominal elongation; in quadrant mode, mismatch varied between –2.79 µm and –20.41 µm. When the feedback control system was switched on, mismatch varied between –0.02 µm and +0.43 µm (P < 0.001 for all matchings). When the feedback system was off, the elongation mismatch among the 1%, 3%, and 6% agar was also statistically significant (P < 0.001). Elongation was 44.72 ± 4.16 µm with feedback control off and 60.02 ± 1.63 µm with it on (nominal elongation 60 µm; P < 0.001) when emulsifying agar 6% gel fragments. Dispersion of elongation data was also significantly wider when feedback control was turned off.ConclusionsA novel feedback control system effectively controls elongation accuracy regardless of the resistance offered by incremental agar gel concentrations.Translational RelevanceImplementing feedback control in phaco handpieces dramatically improves surgical accuracy. The translational value of this research relies on its immediate applicability to routine cataract surgery, resulting in a more appropriate use of ultrasound energy.

Ảnh hưởng của tần suất xử lý ozone lên chất lượng trứng cua biển (Scylla paramamosain)

This study aimed to determine the appropriate application frequency of ozone for disinfection of incubated eggs of mud crab. The experiment was designed with four treatments and triplicated including (i) control (iodine disinfection), (ii) ozone daily disinfection, (iii) ozone disinfection every 2 days, and (iv) ozone disinfection every 3 days disinfection. Ozone was applied to the rearing tanks through a venturi pump for 60 seconds at a concentration of 0.1 ppm. The results showed the hatching rate and number of larvae in the treatment with daily ozone disinfection were 57.4% and 4.52 x 103 ind. which were not significantly lower than those from the control (62.3% and 5.51 x 103 ind., respectively). Fungus and parasite infection ratios were statistically lower in the treatment exposed to daily ozone disinfection. Total bacteria and Vibrio counts on the incubated eggs in treatments with ozone disinfection were significantly lower than those of the control. The results suggested that ozone disinfection could be applied daily in the mud crab hatchery practices.

In situ rapid evaporative ionization mass spectrometry method for real-time discrimination of Pelodiscus sinensis in different culturing modes without sample preparation

Rapid evaporative ionization mass spectrometry (REIMS) is a recently developed technology for real-time lipidomics profiling of biological tissues without time-consuming sample preparation. In this study, a REIMS method was established for the differentiation of Pelodiscus sinensis cultured in two distinct modes, the organic ones cultured ecologically in an outdoor pond, and the greenhouse ones cultured in the greenhouse. The tissue samples were analyzed directly using an electrosurgical monopolar cutting handpiece, and the aerosol generated was simultaneously transferred into the mass spectrometer by a Venturi pump. Finally, two turtle groups were successfully differentiated with the REIMS method, and the markers for identification were detected. The results of method validation and the successful application of this method indicated that the well-established real-time REIMS technique is rapid, high-throughput, efficient, and reliable in detecting the food fraud of P. sinensis.

Teaching venturi electrospray mass spectrometry with amino acid analysis

There is an urgent need to update the ways in which undergraduates learn science technology. In this laboratory experiment, students improved their knowledge of the chemistry used in the analysis of amino acids by mass spectrometry with electrospray ionization using venturi pump (VESI-MS) sample introduction. Amino acid analysis using mass spectrometry is connected to a variety of chemical issues, from macroscopic concepts of solution preparation and the use of average molecular mass (g mol−1) to microscopic concepts of chemistry, such as exact molecular mass (Da), organic functional groups, single mass spectrometry (MS) to identify ions from molecules in solution, and tandem mass spectrometry (MS2) to access structural features of the ions formed. The experiment dealt with solution preparation, physical chemistry concepts involved in VESI, and organic chemistry concepts in ion analysis by MS and MS2 experiments in a triple quadrupole mass spectrometer.

Prospective randomized comparative study between venturi and peristaltic pumps in WhiteStar Signature® phacoemulsification machine.

PurposeTo compare intraoperative parameters between venturi and peristaltic pump in WhiteStar Signature® phacoemulsification machine using the bevel-down technique.SettingHospital Oftalmológico de Brasília, Brasília, Federal District, Brazil.DesignProspective, comparative, patient-masked study.MethodsThree hundred eyes were randomly assigned to have a phacoemulsification procedure with WhiteStar Signature® using either peristaltic (n=150 eyes) or venturi (n=150 eyes) pumps by a single surgeon (WTH). Elliptical ultrasound setting and prefracture (prechop or preslice) techniques were used in all cases. Cataract nucleus density was graded using lens opacities classification system III and Pentacam Nucleus Staging classification. Clinical measurements included preoperative- and postoperative- corrected visual acuity, preoperative and 2-month postoperative endothelial cell counts, and preoperative and 1-day postoperative central corneal thickness. Intraoperative measurements at the end of the case were phaco time, fluid used, total case time, and Efx energy.ResultsThere were no statistically significant differences between groups regarding age, cataract density, and phaco time (P>0.05). Intraoperatively, we observed significantly less ultrasound energy (P=0.011), case time (P=0.0001), and balanced saline solution (P=0.001) usage in the venturi group. Clinically, both fluidic settings can provide similar clinical outcomes and visual recovery, regarding corrected distance visual acuity, endothelial cell count, and central corneal thickness.ConclusionOur data show that to minimize fluid use, case time, and energy with the prefracture technique, the venturi pump was the most efficient system and was statistically superior to peristaltic pump.

Direct analysis of volatile organic compounds in foods by headspace extraction atmospheric pressure chemical ionisation mass spectrometry.

RationaleThe rapid screening of volatile organic compounds (VOCs) by direct analysis has potential applications in the areas of food and flavour science. Currently, the technique of choice for VOC analysis is gas chromatography/mass spectrometry (GC/MS). However, the long chromatographic run times and elaborate sample preparation associated with this technique have led a movement towards direct analysis techniques, such as selected ion flow tube mass spectrometry (SIFT‐MS), proton transfer reaction mass spectrometry (PTR‐MS) and electronic noses. The work presented here describes the design and construction of a Venturi jet‐pump‐based modification for a compact mass spectrometer which enables the direct introduction of volatiles for qualitative and quantitative analysis.MethodsVolatile organic compounds were extracted from the headspace of heated vials into the atmospheric pressure chemical ionization source of a quadrupole mass spectrometer using a Venturi pump. Samples were analysed directly with no prior sample preparation. Principal component analysis (PCA) was used to differentiate between different classes of samples.ResultsThe interface is shown to be able to routinely detect problem analytes such as fatty acids and biogenic amines without the requirement of a derivatisation step, and is shown to be able to discriminate between four different varieties of cheese with good intra and inter‐day reproducibility using an unsupervised PCA model. Quantitative analysis is demonstrated using indole standards with limits of detection and quantification of 0.395 μg/mL and 1.316 μg/mL, respectively.ConclusionsThe described methodology can routinely detect highly reactive analytes such as volatile fatty acids and diamines without the need for a derivatisation step or lengthy chromatographic separations. The capability of the system was demonstrated by discriminating between different varieties of cheese and monitoring the spoilage of meats.

Investigation and control of the - to -transition in a novel sub-atmospheric pressure dielectric barrier discharge

A novel flow-driven dielectric barrier discharge concept is presented, which uses a Venturi pump to transfer plasma-generated reactive oxygen and nitrogen species from a sub-atmospheric pressure () discharge region to ambient pressure and can be operated with air. By adjusting the working pressure of the device, the plasma chemistry can be tuned continuously from an ozone ()-dominated mode to a nitrogen oxides ()-only mode. The plasma source is characterized focusing on the mechanisms effecting this mode change. The composition of the device’s output gas was determined using Fourier-transform infrared spectroscopy. The results are correlated to measurements of discharge chamber pressure and temperature as well as of input power. It is found that the mode-change temperature can be controlled by the discharge chamber pressure. The source concept is capable of generating an -dominated plasma chemistry at gas temperatures distinctly below . Through mixing of the processed gas stream with a second flow of pressurized air required for the operation of the Venturi pump, the resulting product gas stream remains close to room temperature. A reduced zero-dimensional reaction kinetics model with only seven reactions is capable of describing the observed pressure- and temperature-dependence of the to mode-change.

Automated on-line liquid–liquid extraction system for temporal mass spectrometric analysis of dynamic samples

Most real samples cannot directly be infused to mass spectrometers because they could contaminate delicate parts of ion source and guides, or cause ion suppression. Conventional sample preparation procedures limit temporal resolution of analysis. We have developed an automated liquid–liquid extraction system that enables unsupervised repetitive treatment of dynamic samples and instantaneous analysis by mass spectrometry (MS). It incorporates inexpensive open-source microcontroller boards (Arduino and Netduino) to guide the extraction and analysis process. Duration of every extraction cycle is 17 min. The system enables monitoring of dynamic processes over many hours. The extracts are automatically transferred to the ion source incorporating a Venturi pump. Operation of the device has been characterized (repeatability, RSD = 15%, n = 20; concentration range for ibuprofen, 0.053–2.000 mM; LOD for ibuprofen, ∼0.005 mM; including extraction and detection). To exemplify its usefulness in real-world applications, we implemented this device in chemical profiling of pharmaceutical formulation dissolution process. Temporal dissolution profiles of commercial ibuprofen and acetaminophen tablets were recorded during 10 h. The extraction-MS datasets were fitted with exponential functions to characterize the rates of release of the main and auxiliary ingredients (e.g. ibuprofen, k = 0.43 ± 0.01 h−1). The electronic control unit of this system interacts with the operator via touch screen, internet, voice, and short text messages sent to the mobile phone, which is helpful when launching long-term (e.g. overnight) measurements. Due to these interactive features, the platform brings the concept of the Internet-of-Things (IoT) to the chemistry laboratory environment.

Safety Profile of Venturi Versus Peristaltic Phacoemulsification Pumps in Cataract Surgery Using a Capsular Surrogate for the Human Lens

To compare the risk of capsular rupture of the human lens during cataract surgery from contact by phacoemulsification needles using different vacuum pumps, ultrasound modalities, and contact angles. Experimental laboratory investigation. The John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, was the setting for this study. A Signature (Abbott Medical Optics, Inc) phacoemulsification machine was used in peristaltic and Venturi vacuum modes with transversal and micropulsed ultrasound. Contact was made with a capsular surrogate to achieve tip occlusion or tip contact only. Breakage rates were calculated by analyzing the capsular surrogate under a surgical microscope. Venturi and peristaltic pump modes had similar risk of capsular rupture, regardless of whether the data were analyzed with tip occlusion data included (44.2% peristaltic vs 40.2% Venturi, P = .047) or excluded from the analysis (66.3% peristaltic vs 60.3% Venturi, P = .013). Transversal ultrasound was significantly more likely to cause capsular rupture than micropulsed ultrasound (69.8% vs 56.8%, P < .0001). Tip contact was significantly more likely than tip occlusion to cause capsular rupture (63.3% vs 0%, P < .0001). There is no significant difference in risk of capsular rupture using Venturi rather than peristaltic vacuum pumps, while transversal seemed to increase the risk when compared to micropulsed ultrasound. Tip occlusion is not a risk factor for capsular rupture, as all breaks in the capsular surrogate occurred with tip contact.

A compact 3D-printed interface for coupling open digital microchips with Venturi easy ambient sonic-spray ionization mass spectrometry.

Digital microfluidics (DMF) based on the electrowetting-on-dielectric phenomenon is a convenient way of handling microlitre-volume aliquots of solutions prior to analysis. Although it was shown to be compatible with on-line mass spectrometric detection, due to numerous technical obstacles, the implementation of DMF in conjunction with MS is still beyond the reach of many analytical laboratories. Here we present a facile method for coupling open DMF microchips to mass spectrometers using Venturi easy ambient sonic-spray ionization operated at atmospheric pressure. The proposed interface comprises a 3D-printed body that can easily be "clipped" at the inlet of a standard mass spectrometer. The accessory features all the necessary connections for an open-architecture DMF microchip with T-shaped electrode arrangement, thermostatting of the microchip, purification of air (to prevent accidental contamination of the microchip), a Venturi pump, and two microfluidic pumps to facilitate transfer of samples and reagents onto the microchip. The system also incorporates a touch-screen panel and remote control for user-friendly operation. It is based on the use of popular open-source electronic modules, and can readily be assembled at low expense.

Instantaneous flow rate of vitreous cutter probes.

We report on instantaneous volumetric flow rate of vitreous cutters measured by means of particle image velocimetry (PIV). In an in vitro experimental study, vitreous cutters mounting a regular blade (RB) or modified Twedge blade (TB) engineered for higher flow were connected to a console machine equipped with a double peristaltic and Venturi pump, and immersed in balanced salt solution (BSS). Instantaneous flow was measured on aspiration tubing sections proximal to the cutter hand piece. Measures settings were as follows: (1) regular functioning at 3000 and 6000 cuts per minute (cpm) with 300 mm Hg aspiration with both pumps, (2) aspiration tubing clamped proximal to pump cassette, and (3) aspiration tubing clamped proximal to hand piece, and (4) flow fluctuation as a function of cut rate also was calculated. For main outcome measures, instantaneous volumetric flow rate in mL/min and flow fluctuation measured as the standard deviation of flow rate were measured. Regular functioning shows sinusoidal flow oscillating at cut rate frequency, with amplitude between ±50 mL/min at 3000 cpm and ±35 mL/min at 6000 cpm. The TB always determined a bimodal wave and neither blade nor pump type influenced the sinusoidal pattern of flow. Clamping aspiration tubing zeroes flow, but does not influence fluctuation frequency or amplitude. Clamping at the hand piece determined a significantly higher oscillation. Oscillation amplitude retain a typical resonance pattern with significant changes in function of cut rate and resonance occurs at approximately 4000 cpm. Cutter blade action determines instantaneous flow rate fluctuation that interferes significantly with cutter suction and hampers a steady suction through cutter port. In a surgical scenario, this translates into a higher risk of inadvertent retinal entrapment and lower predictability of cutter behavior, especially at frequency approaching resonance.

Introducing new vitreous cutter blade shapes: a fluid dynamics study.

To assess the efficacy of novel vitreous cutter blades compared with the regular guillotine by means of particle image velocimetry. Tested blades included a regular blade (RB) and newer designs where a circular (hole blade [HB]) or a slit aperture (slit blade [SB]) had been opened proximal to the cutting edge. Twenty-three-gauge probes were immersed in BSS or egg albumen, and high-speed video (1,000 frames per second) was recorded. Duty cycle, flow rate, and acceleration generated by Venturi and peristaltic pumps were measured under cutter settings simulating "low-speed" vitrectomy (1600 cuts per minute, 200 mmHg vacuum) and "high speed" vitrectomy (3000 cuts per minute, 300 mmHg vacuum). The SB and HB had a significantly more favorable duty cycle than that of the RB (P < 0.01) and higher BSS flow rate regardless of the aspiration. The SB flow rate in albumen was significantly higher than that of the HB and RB only over 1,000 cuts per minute using a peristaltic pump and at any cut rate with Venturi pump (P < 0.001). The SB also yielded the lowest fluid acceleration than both the HB and SB (P < 0.001 in all cases). The HB and SB proved to be significantly more efficient than the RB, with better duty cycle and higher flow rate. The SB generated significantly less fluid acceleration than any other tested blade, regardless of the fluid viscosity and pump technology. The SB design is significantly more efficient and possibly safer than both HB and RB.

FLUID DYNAMICS OF VITRECTOMY PROBES

To characterize the fluidics of vitreous cutter port in response to aspiration and blade motion using particle image velocimetry techniques. Diverse surgical scenarios and fluid characteristics were replicated. The 23-gauge vitreous cutters were immersed in seeded Balanced Salt Solution (BSS) (Alcon, Forth Worth, TX) or egg albumen, and high-speed video was recorded. Fluid velocity, kinetic energy (KE), and acceleration generated by Venturi and peristaltic pumps were measured in aspiration only (200 and 300 mmHg), low-speed vitrectomy (1,600 cuts per minute; 200 mmHg vacuum), and high-speed vitrectomy (3,000 cuts per minute; 300 mmHg vacuum) modes. The Venturi pump generated significantly higher KE than peristaltic pump in BSS (P < 0.0001 for each pair), and aspiration only yielded significantly higher KE. Cutting activation generated significant acceleration (P < 0.001), and the peristaltic pump produced higher positive and negative acceleration peaks (P < 0.001) than the Venturi pump. In egg albumen, the peristaltic pump generated significantly more KE than the Venturi pump (P < 0.001) and perturbed a much wider area. Acceleration was higher for the peristaltic pump in low-speed mode (P < 0.001), whereas in high-speed modality, the Venturi pump produced the highest acceleration peaks (P < 0.001). Pump type and blade motion largely influence velocity, KE, and acceleration. In BSS, the Venturi pump induces higher KE and acceleration, although perturbing fluid less diffusely. In egg albumen, the peristaltic pump perturbed a much wider area and induced a higher KE and acceleration than the Venturi pump, even more so at lower cut rates. As a conclusion, particle image velocimetry allowed precise characterization of fluid velocity in response to cutter activation, suggesting a pragmatic approach to surgical scenarios.

Automated system for extraction and instantaneous analysis of millimeter-sized samples

Adequate sample treatment is critical when employing mass spectrometry (MS) in the analyses of complex biological matrices. Despite various improvements, it is generally difficult to automate the process of preparing solid biological samples for MS analysis. Here we demonstrate a facile approach for automation of the whole analysis (from an untreated sample to the final result). The proposed platform enables disruption and extraction of relatively small samples (individual fruit flies, fragments of tea leaves, powdered drug sampled with a cotton bud), and almost simultaneous analysis of the obtained extract within less than 10 min, and with very little intervention of the analyst. The operation is straightforward: once a sample is placed in the sample chamber, the analyst only needs to press a button on the touch screen of the user interface. The programmed open-source electronic device triggers addition of a small amount of solvent, and subsequent mechanical disruption/extraction of the specimen under controlled conditions (thermostated chamber). A small volume of the extract is directed to the ion source of the mass spectrometer incorporating a Venturi pump. During the operation of the instrument, fluorescence intensities (excitation wavelength windows: 320–380 and 460–500 nm) as well as MS extracted ion currents are recorded simultaneously. In the case of fruit fly samples, ∼70 signals were recorded in both modes while the analysis of green tea leaves yielded ∼30 signals. The resulting data reveal time-resolved extraction profiles characterizing every sample.

Correlation between Cataract Grading by Scheimpflug Imaging and Phaco Time in Phacoemulsification using Peristaltic and Venturi Pumps

To study the correlation among cataract grading system by Scheimpflug imaging (Oculus Pentacam® Nucleus Grading System [PNS]), effective phaco time (EPT), and surgical time (ST) using peristaltic and venturi pumps on the Whitestar Signature Phaco System (Abbott Medical Optics, Inc., Santa Ana, California, USA). Patients scheduled to have bimanual microincision phacoemulsification by the same surgeon (T.F.) had Pentacam® Scheimpflug assessment using PNS and were randomly distributed into 2 groups. In group 1, surgery was performed using peristaltic pump, and in group 2, using venturi pump. Parameters assessed in both groups included EPT and ST. Sixty eyes that had uneventful clear cornea phacoemulsification with implantation of foldable intraocular lens (IOL) were evaluated, 30 in each group. The EPT was statistically superior with higher nuclear density grades for both groups 1 and 2 (group 1 Spearman R = 0.739, p<0.001; group 2 Spearman R = 0.924, p<0.001). The ST statistically increased with nucleus density for both groups 1 and 2 (group 1 Spearman R = 0.620, p<0.001; group 2 Spearman R = 0.643, p<0.001). Group 2 presented statistically significant reduction on median ST compared with group 1 for nucleus grading 2, 3, 4, and 5. The PNS is an objective and reproducible method of grading nuclear cataract density and had a correlation with EPT. Peristaltic and venturi pumps in Signature Phaco System were similar in EPT but venturi pump reduced the median ST in nucleus with higher PNS, without repercussion on complications or anterior chamber stability.