Drop Volume Research Articles

Enhancement Drip Dose Infusion Accuracy Based on Optocoupler and Microcontroller Sensor

Setting the speed of infusion drops in a manual manner is by adjusting the clamp on the infusion set, where the nurse must count the number of infusion drops in the chamber at the same time as looking at the time on the watch. This makes the setting is subjective and cannot be shown with numbers. In addition, nurses cannot monitor the infusion rate continuously. Therefore, it is necessary to enhancement the accuracy of giving infusion drops so that they can be objective and can be shown with numbers and monitor continuously. This enhancement in accuracy is done by making a instrument with an optocoupler to detect infusion drops. For processing uses an arduino microcontroller to be the speed and the volume of infusion and detects changes in the rate of infusion drops significantly. And for the display uses a OLED display and a buzzer as an indicator. The results of this instrument, it can be seen that the optocoupler can detect infusion drops in the infusion set properly. This good sensor reading has implications for accurate readings of the infusion drop rate and infusion drop volume. This enhancement in accuracy is not only for the macro drip (20 drops/cc) but also for the micro drip (60 drops/cc). The accuracy of volume readings ranges from 95-99% for the macro drip and 94.5-97% with the micro drip. And for speed accuracy ranges from 92.37-98.46%. Based from the results of this test, enhancement the accuracy of the infusion drip dose administration can be done by making a patient infusion drip dose calculator. This equipment uses an optocoupler sensor, arduino microcontroller, OLED display and buzzer. With the use of this instrument, nurses can be more accurate in regulating the rate of infusion drops given to patients and can monitor it continuously if there is a significant change in infusion rate.

Stability Bounds for Micron Scale Ag Conductor Lines Produced by Electrohydrodynamic Inkjet Printing.

Continuous conducting lines of width 5–20 μm have been printed with a Ag nanoparticle ink using drop-on-demand (DOD) electrohydrodynamic (EHD) inkjet printing on Si and PDMS substrates, with advancing contact angles of 11° and 35°, respectively, and a zero receding contact angle. It is only possible to achieve stable parallel sided lines within a limited range of drop spacings, and this limiting range for stable line printing decreases as the contact angle of the ink on the substrate increases. The upper bound drop spacing for stable line formation is determined by a minimum drop overlap required to prevent contact line retraction, and the lower bound is governed by competing flows for drop spreading onto an unwetted substrate and a return flow driven by a Laplace pressure difference between the newly deposited drops and the fluid some distance from the growing tip. The upper and lower bounds are shown to be consistent with those predicted using existing models for the stability of inkjet printed lines produced using piezoelectric droplet generators. A comparison with literature data for EHD printed lines finds that these limiting bounds apply with printed line widths as small as 200 nm using subfemtoliter drop volumes. When a fine grid pattern is printed, local differences in Laplace pressure lead to the line width retracting to the minimum stable width and excess ink being transported to the nodes of the grid. After printing and sintering, the printed tracks have a conductivity of about 15%–20% of bulk Ag on the Si substrate, which correlates with a porosity of about 60%.

Use of a Geometric Parameter for Characterizing Rigid Films at Oil-Water Interfaces.

Interfacial tension and dilatational rheology are often used to characterize the mechanical response of a liquid interface using axisymmetric drop shape analysis (ADSA). It is important to note that for systems dominated by adsorption/desorption of surfactants, the contributions of extra mechanical stresses are negligible; thus, the Young-Laplace equation remains valid. However, for interfaces dominated by extra stresses, as in the case of particle monolayers or asphaltenes that clearly exhibit a skin (a rigid film), the nature of the elastic response is fundamentally different and the validity of the equation is questionable. Calculation of the interfacial tension and dilatational elasticity using drop shape analysis depends critically on the drop shape following the Young-Laplace equation. If the interface becomes more like a solid, the drop shape will deviate from being purely Laplacian. Indeed, the drop will exhibit a wrinkled surface as collapse continues. The geometric parameter RV/A, defined as the ratio (dV/V)/(dA/A) with V is the volume of the drop and A is the area of the interface), allows one to measure the deviation of the drop shape from purely Laplacian. For a simple interface (pure liquids or surfactant solutions), RV/A is quite close to the theoretical value of 1.5 of a perfect sphere. Nevertheless, if the molecules adsorbed at the interface begin to interact strongly, the ratio can vary. In the limit of long-time-scale experiments, RV/A of some drops approaches 2. We studied the evolution of the parameter RV/A for different systems, from simple to complex, as a function of oscillation frequencies and amplitudes of drop volume. The results obtained were compared to the values of the interfacial moduli and drop shape behavior to better characterize the regime change.

Vapor Lubrication for Reducing Water and Ice Adhesion on Poly(dimethylsiloxane) Brushes

Fast removal of small water drops from surfaces is a challenging issue in heat transfer, water collection, or anti-icing. Poly(dimethylsiloxane) (PDMS) brushes show good prospects to reach this goal because of their low adhesion to liquids. To further reduce adhesion of water drops, here, the surface to the vapor of organic solvents such as toluene or n-hexane is exposed. In the presence of such vapors, water drops slide at lower tilt angle and move faster. This is mainly caused by the physisorption of vapor and swelling of the PDMS brushes, which serves as a lubricating layer. Enhanced by the toluene vapor lubrication, the limit departure volume of water drop on PDMS brushes decreases by one order of magnitude compared to that in air. As a result, the water harvesting efficiency in toluene vapor increases by 65%. Benefits of vapor lubrication are further demonstrated for de-icing: driven by gravity, frozen water drops slide down the vertical PDMS brush surface in the presence of vapor.

Three-Dimensional Printed Microdevice to Enhance Headspace Microextraction for Enrichment of Histamine in Milk.

In this work, a three-dimensional (3D) printed microdevice was designed to fix a drop of extractant that was applied to the enrichment of the most toxic biogenic amine, histamine, by headspace single-drop microextraction (HS-SDME). Concomitantly, based on the hybridization chain reaction of the histamine aptamer isothermal nucleic acid amplification strategy, a new fluorescence sensing method was developed to realize the highly sensitive detection of histamine. This is the first application of a 3D-printed microdevice to realize the HS-SDME process, which, among other advantages, effectively solves the problem of unstable and variable drop volumes that can plague traditional SDME and ensures the accuracy and repeatability of the extraction process. The calibration linear range of this SDME-fluorescence method was from 10 pM to 5 μM (R2 > 0.98), and the limit of detection was as low as 3 pM. In addition, the method was successfully demonstrated to determine histamine spiked in milk, with recoveries of between 93% and 104%, and relative standard deviations of less than 5%. The method established in this study has important practical significance for food safety monitoring and human health and provides new ideas and solutions for the design and application of biosensors.

Factors affecting the choice and usage of glucometers in children and adolescents with type 1 diabetes mellitus

Introduction. Glucometers are the most available devices for glycemic control in children with type 1 diabetes mellitus (DM1). Changing social conditions and development of modern technologies can influence patients' preferences.Aim. To study the factors affecting the choice and usage of glucometers in children and adolescents with DM1 in real clinical practiceMaterials and methods. In 06.2020-05.2021, 107 patients 12.0 (8.8; 15.0) years with DM1 for 4.4 (2.0; 7.6) years filled in a questionnaire about the usage of glucometers.Results and discussion. While questioning patients used glucometers Contour (34 patients, 31.7%), OneTouch (33, 30.8%), Accu-Check (33, 30.8%), Satellit (3, 2.8%), AiChek (1, 0.9%), Easy Touch (1, 0.9%). Children start to use glucometer together with parents at 4.5 (4.0; 5.3) years, by themselves - at 6.0 (5.0; 7.0) years. Do not clean hands before finger puncture 55 (51.4%) patients, use wet wipes - 24 (22.4%), use antiseptics - 26 (24.3%), wash hands with soap - 2 (1.9%). Episodes of inflammation at the sites of punctures were reported by 21 patients (19.6%); patients using antiseptics faced with inflammation significantly rarer than others - OR = 2.7 (95% CI 0.6-12.6). Errors of glucometers were reported by 48 (44.9%) patients independently to method how they clean hands. Choosing glucometers patients pay attention to accuracy (76, 71.0%), blood drop volume (48, 44.9%), memory amount (22, 20.6%), size of device (22, 20.6%), mobile application (17, 15.9%), invisibility (10, 9.3%), design (7, 6.5%); and lightening, comfortable blood pin, battery indicator, possibility to add blood sample (1 per each, 0.9%).Conclusion. Children and adolescents with DM1 use glucometers Contour, OneTouch, and Accu-Check more often. Self-dependent usage of glucometers starts at preschool age. The majority of patients do not clean hands before puncture of a finger; antiseptics usage decreases the probability of inflammation. Choosing glucometers patients pay attention to technical characteristics and comfort.

Multi-scale and multi-physics analysis, design optimization, and experimental validation of heat exchangers utilizing high performance, non-round tubes

Air-to-refrigerant heat exchangers (HXs) are fundamental components in HVAC&R systems, and considerable research has been dedicated designing continually smaller, lighter, and more efficient HX designs. In recent years, researchers have leveraged advancements in Computational Fluid Dynamics (CFD), Finite Element Analysis (FEA), and optimization algorithms to consider primary tube shape and topology optimization to design highly compact, high performance HXs for a multitude of applications.In this research, we present a computationally efficient, comprehensive, multi-scale, and multi-physics analysis and optimization method for air-to-refrigerant HXs featuring automated CFD and FEA simulations and approximation-assisted optimization. This methodology was utilized to design HXs with shape-optimized, non-round tubes which outperform current state-of-the-art tube-fin HXs without compromising structural integrity. The optimal HXs were shown to deliver similar thermal performance to the baseline HXs while also achieving more than 20% reductions in airside pressure drop and core envelope volume and more than 30% reduction in internal volume.Comprehensive experimental validation of the optimization methodology was conducted through the testing of two prototypes in a standardized wind tunnel facility under multiple operating conditions. For prototype #1 under dry evaporator conditions, the predicted heat load agreed within ± 10% of measured values and the predicted airside pressure drop agreed within ± 30%, while for dehumidifying conditions, the predicted sensible and latent heat loads agreed within ± 10% and ± 20% of the measured values, respectively. For prototype #2, the predicted condenser heat load agreed within ± 3.0% of measured values, and the predicted airside pressure drop agreed within ± 27%. The acceptable agreement between simulation and experimental results for the present application highlights the flexibility of the novel optimization methodology to design next generation HXs with improved performance and reduced volume, weight, and environmental impact.

Throughfall drop sizes suggest canopy flowpaths vary by phenophase

Water flowpaths caused by incident rainfall onto forest canopy surfaces have a notable effect on the water budgets and chemistry of wooded ecosystems. This study revealed varying canopy flowpaths and residence times at the intra-event scale and across the phenological transition from leafed to leafless states for a set of three American beech (Fagus grandifolia Ehrh.) trees in a multilayered canopy. Simultaneous measurements of raindrops and throughfall drops by fifteen laser disdrometers over five rain events were analyzed during the transition from leafed to leafless phenophases. Throughfall was partitioned into free throughfall, splash throughfall, and canopy drip with four drop size classes. Throughfall drop size distributions and volume of each throughfall type varied at both intra-event and inter-event scales. Smaller canopy drips, <5.5 mm in diameter, were initiated earlier in rain events, whereas more rainfall accumulation was necessary to generate larger canopy drips, >5.5 mm in diameter. Smaller canopy drips were more dominant in the leafed phenophase when some structurally-mediated woody surface drip points were more muted. These results suggested throughfall from foliar surfaces generated smaller-sized canopy drip with shorter residence time, whereas throughfall from structurally-mediated woody surface drip points generated larger-sized canopy drip with longer residence time. There was also an increase in both free throughfall and splash droplets from leafed to leafless states, consistent with increased canopy gaps and direct interaction with woody surfaces in the leafless state. Based on the results, a conceptualization of the genesis and development of leaf and branch flowpaths in canopies is proposed.

Numerical estimation of droplet motion on linear wettability gradient surface in microgravity environment

Self-propelled motion of liquid droplets on wettability gradient surface (WGS) is an emerging field due to its various applications. Simulations are performed to investigate droplet motion on WGS under gravity and microgravity conditions. Herein, transient, laminar, 3-dimensional Continuity and Navier-Stokes equation are solved for the computational domain consisting of liquid water droplet on WGS in presence of air, applying no-slip, constant contact angle boundary conditions at surface using ANSYS FLUENT® for the computational domain. Simulation results are validated with the available experimental and simulation results and are found to be in good agreement. Further, a parametric study is performed to exemplify the effect of gravity, initial contact angle, drop volume and surface gradient on droplet velocity, spreading, position and surface shear stress. Present study demonstrates, shape evolution of droplet moving on WGS is attributed to caterpillar alike inching motion in both gravity and microgravity conditions. Droplet is almost stagnant on surface with initial superhydrophobic angle (θhigh > 150°) with low gradient (Δθe = 0.2° and 1°). However, despite of higher spreading droplet accelerates on hydrophobic surfaces (θhigh = 100°) with higher gradient (Δθe = 10°). The effect of gravity is negligible for small droplets. However, substantially affects large droplet due to increased value of Bond number. Present results are helpful for designing and optimizing wettability graded surfaces which endures droplet splitting and coalescence in various microgravity engineering systems. In addition, the WGS are also advantageous for heat transfer augmentation.

P-773 Assessment of the putative impact of culture strategies, oocyte/embryo manipulations, and operators: a retrospective analysis of 3705 blastocyst culture cycles and 2604 single blastocyst transfers

Abstract Study question Do the culture strategies, oocyte/embryo manipulations, and operators impact blastulation-rates per cohort of metaphase-II oocytes (BR per MII-oocytes) and/or live-birth-rates per single-embryo-transfer (LBR per SET)? Summary answer Undisturbed culture improved the BR per MII-oocytes, while culture drop volumes ≥80ml in the well-of-the-well system were associated with increased LBR per untested/euploid blastocyst SET. What is known already IVF lab performance is critical to achieve success in IVF. Yet, while a consensus exists on the main key-performance-indicators (KPIs), namely BR and LBR, and their inherent benchmark values, the strategies to fulfil them are still poorly standardized. The plasticity of human embryos along with the disparities in the patient populations might mask even largely different outcomes across clinics. Therefore, clear guidelines shall outline which procedures to standardize and carefully monitor in IVF laboratories. Here we investigated different embryo culture strategies, manipulations, and operators for their effect on BR and LBR per SET, adjusting the results for all main confounders. Study design, size, duration Retrospective analysis of 3705 cycles with ≥1 MII-oocyte and 2604 SETs (January2019-March2021). BR per MII-oocytes and LBR per SET were the main outcomes. Embryo-twinning was also assessed. The putative impact of culture strategies, manipulations, and operators’ expertise (0-5yr,6-11yr or &amp;gt; 12yr) was determined via regression analyses adjusted for possible confounders (autologous/donated oocytes, age, primary/secondary infertility and duration, sperm factor; for SET: also endometrial preparation, age at transfer, number of consecutive transfer, untested/euploid blastocyst, quality, and day). Participants/materials, setting, methods In donation cycles, only vitrified oocytes were used. In Preimplantation-Genetic-Testing (PGT) cycles, no assisted-hatching was performed and only euploid non-mosaic vitrified-warmed blastocysts were transferred. The culture strategies assessed were undisturbed (Embryoscope, Geri and Embryoscope-plus)/disturbed (KSystems), volume and approach (drops ≤30ml with single-culture or ≥ 80ml with well-of-the-well approaches), humidified/non-humidified atmosphere and media refreshed/not-refreshed. The manipulations assessed were oocyte/blastocyst vitrification (performed/not-performed), oocyte retrieval and denudation performed with oil overlay (yes/not), laser-assisted artificial-shrinkage (performed/not-performed), trophectoderm biopsy (performed/not-performed). Main results and the role of chance The only confounders on BR per MII-oocytes (overall:39.1±26.6%) were sperm factor and oocyte age. The linear regressions showed benefits for humidified atmosphere (unstandardized B-coefficient:+2.9%, p = 0.01), manipulations with oil overlay (+3.9%, p = 0.03) and drops≥80ml with a well-of-the-well approach (+4.3%, p &amp;lt; 0.01). However, only the positive effect of undisturbed incubators was significant when adjusting for confounders [41.7±27.8% (N = 1440 cycles) versus 37.5±25.7% in a disturbed incubator (N = 2265 cycles); unstandardized B-coefficient:+5.6%, 95%CI +3.9% to + 7.3%, standardized beta-coefficient:-0.103,p&amp;lt;0.01]. The main confounders on LBR per SET (overall: N = 1044/2604, 40.1%) were oocyte age, number of consecutive transfer, blastocyst chromosomal status (untested/euploid), quality and day. The univariate logistic regressions showed a benefit for undisturbed incubators (OR:1.3, 95%CI 1.1-1.5, p &amp;lt; 0.01), humidified atmosphere (OR:1.4, 95%CI 1.1-1.7, p &amp;lt; 0.01) and media refresh (OR:1.3, 95% 1.01-1.8, p = 0.05). However, only the use of drops ≥80ml with a well-of-the-well approach rather than drops ≤30ml with a single-culture approach involved an improvement when adjusting for confounders (untested SETs: N = 71/171, 41.5% versus N = 434/1284, 33.8%; euploid SETs: N = 170/316, 53.8% versus N = 369/833, 44.3%; multivariate-OR:1.33, 95%CI 1.12-1.58, adjusted p-value&amp;lt;0.01). This result was confirmed in a sub-analysis across only first patients’ SETs. Lastly, no feature under investigation was associated with embryo-twinning (overall: N = 23/1243, 1.9% and N = 14/1044, 1.3% per pregnancy and delivery, respectively). Limitations, reasons for caution Retrospective single center study. Only ICSI cycles and continuous culture media were assessed. Cleavage stage SETs were excluded. All operators had at least 3yr of experience. Perinatal and gestational outcomes were not evaluated. Wider implications of the findings Real-life data adjusted for confounders may unveil fluctuations in critical KPIs mainly imputable to culture strategies. An impact seldom derives from oocyte/embryo manipulations if experienced operators adopt validated protocols. An accurate interpretation of these evidence shall lead to properly designed studies with problem-solving/progress-building purposes, and guidelines to standardize culture practices. Trial registration number Not applicable

Novel genetic algorithms for femtoliter jetting using multi-nozzle MEMS printheads (femtoliter jetting using MEMS printheads)

Piezoelectric inkjets have enabled highly precise, customized material deposition for the micro and nanofabrication industries. Inkjet performance relies on a delicate balance between hardware manufacturing precision and tolerancing, material rheology, and the associated actuation-waveform for drop ejection. For a multi-nozzle inkjet system, the important performance metrics include drop volume resolution, inter-nozzle drop volume variation, overall drop-placement accuracy, jetting frequency (related to throughput), and long-term reliability. Cutting-edge applications typically require minimizing drop volume to 1 pL or less; drop placement accuracy of <10 mm, 3-σ; maintaining high jetting frequency of >10 kHz; and achieving reliable long-term operation, e.g., >1 month of continuous operation without any faults. Here, we strive towards a global optimum in drop resolution while adhering to constraints related to placement accuracy and reliability, at a fixed jetting frequency of 14.2 kHz. Our approach is to explore novel genetic algorithms that generate highly complicated waveforms (>100 parameter waveforms) to achieve our global optimum goals. Our automated genetic algorithm (a) starts from rudimentary waveforms that are easily constructed based on empirical knowledge and manual tuning, and (b) systematically increases complexity to generate highly sophisticated waveforms with increasingly greater number of parameters, an approach that is unattainable through manual tuning processes. This approach was developed and implemented using a commercial MEMS-based Fujifilm Samba G3L piezo-inkjet system with 2048 sub-20μm nozzles, with an aqueous diethylene glycol-based ink supplied by Fujifilm. The genetic algorithm operated based on a variable-length chromosome which started with 10 parameter waveforms and evolved into waveforms defined by > 100 parameters, resulting in drop-volume resolution of <600 fL, and maintaining drop placement accuracy to within 10 μm, 3-σ with reliable jetting over at least 30 print fields with the same waveform, each field nominally composed of 340 drops. The best result presented yielded drops with an average volume of 568 fL, which exceeded the manufacturer's specification for drop volume of 2.4 pL by 4.23 times. In summary, we have developed a novel framework for machine-in-the-loop waveform optimization in multi-nozzle inkjet systems to achieve previously unattained drop resolution with high reliability and accuracy.

Ultrasimple and Ultrafast Method of Optical Modulation by Perovskite Quantum Dot Attachment to a Graphene Surface

Optical modulation is the process of modifying the structure and elemental composition of materials so that the main optical parameters, including amplitude, frequency, and phase, are changed. Currently, much research attention has been directed toward ultrafast dynamics, but the process of modulation is often complex. To simplify the optical modulation process and improve the optical properties of perovskites for semiconductor quantum dot (QD) lasers, the process and physical mechanism underlying graphene QD ultrafast modulation of the optical properties of perovskite CsPbBr3 QDs were investigated. The typical cubic structure and square shape of CsPbBr3 QDs were characterized by transmission electron microscopy and X-ray diffraction, respectively. A luminescent peak centered near 540 nm and Stokes shift of 21.34 nm of CsPbBr3 QDs without graphene QDs were measured by absorption and photoluminescence spectroscopy. A maximum modulation shift of 133 nm and a modulation depth of 900% were achieved in CsPbBr3 with graphene. The results indicated that graphene QDs had the best modulation effect on perovskites when the drop volume was 0.05 mL. The process of ultrafast optical modulation via graphene QDs occurring within 1 ps was confirmed by the transient absorption spectrum. The modulation mechanism of graphene to perovskites is presented for guidance. This paper can be used as a reference for the optical modulation of perovskite materials.

33‐3: Invited Paper: Research and Applications of Inkjet Printing for OLED Mass Production

OLEDs (organic light‐emitting diode) are one of the prevalent display technologies and their penetration in the consumer electronic market is fast growing. As a reliable and cost‐effective deposition technique for polymeric planarization layers, inkjet printing has been successfully applied to the mass production of flexible OLED displays. In this paper, we present the concept that for today's common ranges of process layer thickness, the quality and consistency of the deposited polymeric film can be agnostic to the selection of drop volumes. However, printer flexibility in terms of drop size and printhead support is critical to meeting the full range of current and future processes adopting the proven inkjet printing process. Applications utilizing the state‐of‐the‐art Kateeva inkjet printing systems are presented to demonstrate our study and for the reader to be able to assess if inkjet technology could be advantageous for a particular OLED application.

Combined effect of silica nanofluid and wettability on enhanced oil recovery process

The objectives of this study are to characterize the properties of water-SiO2 nanofluid and quantify its flooding efficiency in an initially oil-filled micro-porous medium of two different surface wettability conditions, i.e. water-wet and neutral-wet. The average nanoparticle size (as a result of aggregation) in water-SiO2 nanofluid is characterized using dynamic light scattering method. Viscosity and surface tension of water-SiO2 nanofluid are measured respectively by vibration string and drop volume methods. For the flooding experiments, a transparent PDMS microchannel with internal square obstacles mimicking a porous medium is designed and fabricated. The wettability of PDMS over time, as a result of aging, is investigated. The effect of SiO2 nanoparticles on 3-phases contact angle (nanofluid, crude oil and PDMS) is reported. The flooding efficiency of water-SiO2 nanofluid is then quantified. The results reveal that the best oil recovery process occur when the water-SiO2 nanofluid flooding is used in a neutral-wet surface condition. As the injection rate increases, the oil displacement efficiency decreases. This oil recovery behavior implies the dominant nature of viscous forces at low flow rate. At high flow rate, the effect of viscous force is not obvious.

Application of gas flow headspace liquid phase micro extraction coupled with gas chromatography-mass spectrometry for determination of 4-methylimidazole in food samples employing experimental design optimization.

Background4-Methylimidazole (4-MeI) or 4-methyl-1H-imidazole, a slightly yellowish solid with molecular formula C4H6N2, is a heterocyclic compound which supposedly does not exist as a natural product and is formed when carbohydrates are heating with ammonium compounds. This compound is used in pharmaceuticals, agriculture and photography chemicals, dyes and pigments, and rubber manufacturing. In the present study, a simple and efficient sample preparation method designated gas flow headspace liquid phase microextraction (GF-HS-SDME) was employed for the extraction and preconcentration of 4-methylimidazole (4-MeI) from food and beverage samples, before its determination by gas chromatography-mass spectrometry.ResultTo investigate the optimal conditions for the extraction process in GF-HS-SDME method, factors affecting extraction, including selection of extraction solvent, vial volume, extraction solvent ratio, position of extracting solvent, drop volume, sample volume, stirring speed, temperature, extraction time, sample pH, ionic strength of the sample solution and gas flow rate were optimized by utilizing both one-variable-at-a-time method and Plackett–Burman design. The investigation of protocol was carried out by using a standard solution containing 100.0 μg L−1 of 4-MeI in deionized water.ConclusionIn this study, a simple and green analytical method based on GF-HS-SDME was proposed for the extraction and preconcentration of 4-MeI from foodstuffs, followed by GC–MS determination. The main advantage of this method is its high preconcentration factor and fastness due to the application of an inert gas stream during microextraction.Supplementary InformationThe online version contains supplementary material available at 10.1186/s13065-022-00823-z.

Efficacy and safety of Mydriatic Microdrops for Retinopathy Of Prematurity Screening (MyMiROPS): study protocol for a non-inferiority crossover randomized controlled trial

BackgroundRetinopathy of prematurity (ROP) eye examination screening presupposes adequate mydriasis for an informative fundoscopy of preterm infants at risk, on a weekly basis. Systemic absorption of the instilled mydriatic regimens has been associated with various adverse events in this fragile population. This report aims to present the fully developed protocol of a full-scale trial for testing the hypothesis that the reduced mydriatic drop volume achieves adequate mydriasis while minimizing systemic adverse events.MethodsA non-inferiority crossover randomized controlled trial will be performed to study the efficacy and safety of combined phenylephrine 1.67% and tropicamide 0.33% microdrops compared with standard drops in a total of 93 preterm infants requiring ROP screening. Primary outcome will be the pupil diameter at 45 (T45) min after instillation. Pupil diameter at T90 and T120 will constitute secondary efficacy endpoints. Mixed-effects linear regression models will be developed, and the 95% confidence interval approach will be used for assessing non-inferiority. Whole blood samples will be analyzed using hydrophilic liquid chromatography–tandem mass spectrometry method (HILIC–MS/MS), for gathering pharmacokinetic (PK) data on the instilled phenylephrine, at nine specific time points within 3 h from mydriasis. Pooled PK data will be used due to ethical restrictions on having a full PK profile per infant. Heart rate, oxygen saturation, blood pressure measurements, and 48-h adverse events will also be recorded.DiscussionThis protocol is designed for a study powered to assess non-inferiority of microdrops compared with standard dilating drops. If our hypothesis is confirmed, microdrops may become a useful tool in ROP screening.Trial registrationClinicalTrials.govNCT05043077. Registered on 2 September 2021

The Effect of Ink Supply Pressure on Piezoelectric Inkjet.

Experimental and numerical analysis of the drop-on-demand inkjet was conducted to determine the jetting characteristics and meniscus motion under the control of the ink supply pressure. A single transparent nozzle inkjet head driven by a piezoelectric actuator was used to eject droplets. To control ink supply pressure, the pressure of the air in the reservoir was regulated by a dual valve pressure controller. The inkjet performance and the motion of the meniscus were evaluated by visualization and numerical simulation. A two-dimensional axisymmetric numerical simulation with the dynamic mesh method was performed to simulate the inkjet dynamics, including the actual deformation of the piezoelectric actuator. Numerical simulation showed good agreement with the experimental results of droplet velocity and volume with an accuracy of 87.1%. Both the experimental and simulation results showed that the drop volume and velocity were linearly proportional to the voltage change. For the specific voltages, an analysis of the effect of the ink supply pressure control was conducted. At the maximum negative pressure, −3 kPa, the average velocity reductions were 0.558 and 0.392 m/s in the experiment and simulation, respectively, which were 18.7 and 11.6% less than those of the uncontrolled case of 0 kPa. Therefore, the simulation environment capable of simulating the entire inkjet dynamics, including meniscus movement regarded to be successfully established. The average volume reductions were 18.7 and 6.97 pL for the experiment and simulation, respectively, which were 21.7 and 9.17% less than those of the uncontrolled case. In the results of the meniscus motion simulation, the damping of the residual vibration agreed well with the experimental results according to the ink supply pressure change. Reducing the ink supply pressure reduced the speed and volume, improved the damping of residual vibrations, and suppressed satellite drops. Decreasing ink supply pressure can be expected to improve the stability and productivity of inkjet printing.

Oscillatory motion of viscoelastic drops on slippery lubricated surfaces

The introduction of slippery lubricated surfaces allows for the investigation of the flow of highly viscous fluids, which otherwise will hardly move on standard solid surfaces. Here we present the study of the gravity induced motion of small drops of polymeric fluids deposited on inclined lubricated surfaces. The viscosity of these fluids decreases with increasing shear rate (shear thinning) and, more importantly, they exert normal forces on planes perpendicular to shear directions (elasticity). Despite the homogeneity of the surface and of the fluids, drops of sufficiently elastic fluids move downward with an oscillating instantaneous speed whose frequency is found to be directly proportional to the average speed and inversely to the drop volume. The oscillatory motion is caused by the formation of a bulge at the rear of the drop, which will be dragged along the drop free contour by the rolling motion undergone by the drop. This finding can be considered as a kind of new Weissenberg effect applied to moving drops that combines dynamic wetting and polymer rheology.

The use of tranexamic acid reduces blood loss in osteotomy at knee level: a systematic review

Aim of this systematic review was to evaluate the literature regarding the effect of tranexamic acid (TXA) on the outcome after knee osteotomy. A systematic literature search was carried out in various databases on studies on the use of tranexamic acid in osteotomies around the knee. Primary outcome criterion was the hemoglobin (drop). Secondary outcome criteria were total blood loss, drainage volume, adverse effects such as thromboembolic events, blood transfusions, wound complications and clinical scores. A meta-analysis was performed for quantitative measures. The present study was registered prospectively ( www.crd.york.ac.uk/PROSPERO ; no.: CRD42021229624). Seven studies with 584 patients (TXA group: 282 patients, non TXA group: 302 patients) Hemoglobin decrease (1.54g/dl vs. 2.28g/dl), blood loss (394.49ml vs. 595.54ml) and drainage volume (266.5ml vs. 359.05ml) were significantly less in the TXA group compared to the non TXA group. No thromboembolic event was noted in any study. In the non TXA group four blood transfusions were given. Eleven wound complications occurred in the non TXA group in comparison to two wound complications in the TXA group. The results of the present study show that the application of TXA reduces hemoglobin drop, blood loss and drainage volume. These effects could be responsible for the lesser rate of side effects after administration of TXA during knee osteotomy.

Influence of transient heat flux on boiling flow pattern in a straight microchannel applied in concentrator photovoltaic systems

Concentrated photovoltaic (CPV) overheating due to the high radiation intensity became the critical challenge to preventing its benefits in advancing the photoelectric efficiency. To promote the application of CPV, efficient heat dissipation becomes the key technology. Meanwhile, microchannel flow boiling, as one of the most promising solution to advance cooling of high-flux equipment, has attracted increasing attentions in recent years. However, the fluctuating and non-uniform heat fluxes of CPVs may lead to challenges to microchannel boiling for cooling CPV. Therefore, the transient flow and phase change phenomenon in a microchannel with deionized (DI) water was studied through a numerical modeling on flow boiling. The effects of different sudden heat flux increases on flow boiling two-phase flow pattern were analyzed. It was found that different heat flux increase resulted to different flow pattern evolutions, a much higher sudden increase in heat flux leaded to serious variation of flow pattern, especially the fluctuation of elongated restricted bubbles, which may evolve to annular flow or even dry-out. The vapor phase volume fraction showed a much higher growth rate. When the heat flux increase was raised from 97.96 kW/m2 to 580 kW/m2, the maximum vapor phase volume fraction was increased from 0.104 to 0.8064, and the bubble length increased from smaller than 0.3 mm to 1.5 mm in the dry zone, indicating rapid phase change. Based on analysis on pressure drop and vapor volume fraction variation, the period after receiving sudden heat flux was divided into three stages: initial period, rapid development period, and quasi-stable period. With the rising of heat flux increase from 97.96 to 580 kW/m2, the duration of rapid development period was increased from 0.03 s to 0.066 s, the pressure drop increase was obviously enlarged, from 2.43 kPa to 14.51 kPa, and the vapor phase volume fraction increase in the microchannel was raised by 3.3 times to 25.6 times, indicating more intensive boiling, and deeper effect of higher heat flux increase on the phase change. In addition, the fluctuation intensity of pressure drop in the quasi-stable period was obviously increased from 0.025 to 0.193, demonstrating the advancement in flow boiling instability under higher heat flux increase, which should be controlled.