In-line Pressure Research Articles

Development of a Real-time Force-based Algorithm for Infusion Failure Detection.

Continuous subcutaneous insulin infusion (CSII) is a common treatment option for people with diabetes (PWD), but insulin infusion failures pose a significant challenge, leading to hyperglycemia, diabetes burnout, and increased hospitalizations. Current CSII pumps' occlusion alarm systems are limited in detecting infusion failures; therefore, a more effective detection method is needed. We conducted five preclinical animal studies to collect data on infusion failures, utilizing both insulin and non-insulin boluses. Data were captured using in-line pressure and flow rate sensors, with additional force data from CSII pumps' onboard sensors in one study. A novel classifier model was developed using this dataset, aimed at detecting different types of infusion failures through direct utilization of force sensor data. Performance was compared against various occlusion alarm thresholds from commercially available CSII pumps. The testing dataset included 251 boluses. The Bagging classifier model showed the highest performance metrics among the models tested, exhibiting high accuracy (96%), sensitivity (94%), and specificity (98%), with lower false-positive and false-negative rate compared with traditional occlusion alarm pressure thresholds. Our study developed a novel non-threshold classifier that outperforms current occlusion alarm systems in CSII pumps in detecting infusion failures. This advancement has the potential to reduce the risk of hyperglycemia and hospitalizations due to undetected infusion failures, offering a more reliable and effective CSII therapy for PWD. Further studies involving human participants are recommended to validate these findings and assess the classifier's performance in a real-world setting.

Simultaneous measurements of volume, pressure, optical images, and crystal structure with a dynamic diamond anvil cell: A real-time event monitoring system.

The dynamic diamond anvil cell (dDAC) technique has attracted great interest because it possibly provides a bridge between static and dynamic compression studies with fast, repeatable, and controllable compression rates. The dDAC can be a particularly useful tool to study the pathways and kinetics of phase transitions under dynamic pressurization if simultaneous measurements of physical quantities are possible as a function of time. We here report the development of a real-time event monitoring (RTEM) system with dDAC, which can simultaneously record the volume, pressure, optical image, and structure of materials during dynamic compression runs. In particular, the volume measurement using both Fabry-Pérot interferogram and optical images facilitates the construction of an equation of state (EoS) using the dDAC in a home-laboratory. We also developed an in-line ruby pressure measurement (IRPM) system to be deployed at a synchrotron x-ray facility. This system provides simultaneous measurements of pressure and x-ray diffraction in low and narrow pressure ranges. The EoSs of ice VI obtained from the RTEM and the x-ray diffraction data with the IRPM are consistent with each other. The complementarity of both RTEM and IRPM systems will provide a great opportunity to scrutinize the detailed kinetic pathways of phase transitions using dDAC.

High-Precision Single-Leak Detection and Localization in Single-Phase Liquid Pipelines Using the Negative Pressure Wave Technique: An Application in a Real-Field Case Study

Summary This paper presents a novel workflow for high-precision leak detection in pipeline networks using the negative pressure wave (NPW) technique. The proposed workflow addresses challenges associated with noisy and convoluted pressure transducer data, rapid pressure decay, and the need for robustness in leak event detection. To overcome these challenges, the workflow incorporates data preprocessing techniques for cleansing, normalization, and denoising, as well as dynamic pressure control limit lines to differentiate between pump and leak events. Multiple transducer analysis techniques are used to minimize false positives. Synthetic leak scenarios are generated using the Water Network Tool for Resilience (WNTR) package, enabling a comprehensive assessment of the workflow’s performance. The generated scenarios are validated through pressure history matching against field inline pressure recordings. A dashboard is developed for real-time visualization and verification of leak events. The effectiveness of the workflow is demonstrated through testing on a real network, resulting in the successful detection and precise localization of a confirmed leak event. The workflow proves its capability to achieve high accuracy, with a 100-m resolution in a complex network configuration with 29 pipe sections and 1-Hz pressure signal recordings. For synthetic leak events, a 10-Hz pressure signal is utilized, achieving a remarkable 10-m accuracy. Moreover, the integration of the workflow with supervisory control and data acquisition (SCADA) systems is showcased, highlighting its potential for near real-time leak detection in practical applications. Overall, this paper presents a comprehensive and effective workflow for high-precision leak detection and localization in pipeline networks, offering valuable insights into improving the efficiency and reliability of leak detection systems.

Characterization of large volume subcutaneous injections using computed tomography imaging and simultaneous pressure measurements

Many commercially available biologics, previously delivered only intravenously, are being re-formulated for subcutaneous delivery to improve patient access and compliance. However, due to inherent solubility limitations, large volume injections (more than 2 mL) are typically required. Different strategies are being explored to improve the tolerability of such injections, including the co-formulation with hyaluronidase and/or implementing different needle designs. While there have been separate reports of measuring injection forces and using imaging to track injection delivery and tissue response, there is no current set of methods to simultaneously characterize the injection delivery (bleb) and measure injection pressures. In this study we describe the development of Computed Tomography imaging methods in minipigs to characterize the morphology of the bleb following injection, along with inline pressure measurements to assess subcutaneous pressure during injection using two different injection volumes, 4.5 mL and 9 mL. We show that these parameters change with injection volume, and that inclusion of hyaluronidase in the injection increases bleb dispersion and reduces skin distention while also lowering the injection pressure. This method will likely be a valuable tool for assessing and comparing different injection delivery methods and formulations.

Development of a simple in-die method for determination of capping tendency in rotary tableting machines.

A rotary tableting machine is used for the continuous tableting process. Tableting conditions often result in capping, leading to serious problems during production. Several studies have been conducted to predict the tablet capping tendency. However, as most previous studies were conducted using a compaction simulator, there is a lack of technology that can be readily applied during actual production. Therefore, the present study aimed to develop a novel method for predicting tablet capping in a rotary tableting machine. We hypothesized that capping occurs when residual stress of the tablet inside a die exceeds the critical stress immediately before ejection. Residual stress was evaluated by measuring the in-line die-wall pressure in a rotary tableting machine. Additionally, critical stress was estimated from the tablet strength inside the die using the Rumpf's equation. The critical and residual stresses were compared to determine the capping tendency to some extent. The findings of this study will substantially contribute to the rapid detection of tablet capping during tablet production.

Effect of operating conditions and micro-porous layer on the water transport and accumulation in proton exchange membrane fuel cells

Accurate measurement of water transport in an operating proton exchange membrane fuel cell (PEMFC) and water accumulation in the electrodes is crucial for understanding the impact of operating conditions and transport layer configurations on cell performance. A water balance setup, based on in-line gas flowmeter, pressure, relative humidity and temperature sensors, was developed and demonstrated to track the real-time water transport and accumulation within operating PEMFCs. Current results indicate that changing operating conditions have a dramatic effect on the water transport across the membrane, while the ratio of water transported to produced remains relatively constant with current density. Under dry conditions, water moves from anode to cathode while increasing humidity and decreasing temperature enhance cathode to anode water movement. Adding a micro-porous layer (MPL) to the cathode gas diffusion layer (GDL) increases the water back-diffusion from the cathode to the anode at all operating conditions, but the increase is not very significant and only results in a prominent performance increase at 60 °C and 70% RH. The improved performance at 60 °C and 70% RH is likely due to: (a) increased water vaporization, since less water accumulation was measured in the electrode; and (b) creation of in-plane oxygen pathways in the MPL around localized liquid water blockages in the GDL. Based on these results, the use of different operating conditions might have been the key contributing factor for the different behavior observed when an MPL was introduced in previous literature.

10 clinical tips for advancing patient safety when using syringe pump systems for microinfusion intravenous drug therapy.

10 clinical tips for advancing patient safety when using syringe pump systems for microinfusion intravenous drug therapy.

In-line warming reduces in-line pressure of subcutaneous infusion of concentrated immunoglobulins

Immunoglobulin replacement therapy is a life-saving treatment in patients with immunodeficiency and effective in the management of autoimmune disorders. Immunoglobulins are administered intravenously or subcutaneously, with the latter route reducing systemic reactions and providing an option for self-infusion, increasing patient convenience, while decreasing patient burden, healthcare utilization, and costs. A major limitation with subcutaneous administrations is the frequency of infusion due to limited volumes administrable into subcutaneous space, necessitating increased drug concentration, absorption, and dispersion. Increasing the concentration of immunoglobulins from 10 to 20% halves the required volume, but leads to higher dynamic viscosity, limiting infusion rate. Recombinant human hyaluronidase increases dispersion and absorption of immunoglobulins allowing administration of ≤ 600 mL per site, but does not change viscosity. Since the viscosity of fluids depends on temperature, we tested the feasibility of in-line warming of immunoglobulin formulations to physiological temperatures. In vitro analysis showed no negative impact of in-line warming to 38 °C on product quality. Subcutaneous infusion studies in pigs confirmed the feasibility of infusion rates of up to 7.5 mL/min with in-line warmed TAK-881, an immunoglobulin 20% facilitated with recombinant human hyaluronidase. In-line pressures were reduced compared with conventional immunoglobulin 20%, and local tolerance was not altered. Reduction of in-line pressures was more pronounced with thinner needle sets, indicating a potential benefit for patients. In summary, an in in-line warming device can circumvent the limitation of high viscosity, while product quality and local tolerance are maintained. The results of the presented studies warrant further testing in a phase 1 clinical study.Graphical

Studies on Incorporating Infrared Reflecting Minerals into Viscose Fibres

A mixture of minerals consisting of calcite, dolomite, talc and quartz, known to have infrared (IR) reflecting properties, was mechanically treated and dispersed in aqueous medium and incorporated in viscose solution to be physically entrapped into the fibre structure. The process of incorporation of the mineral mixture in viscose dope involved steps of slurry making by suspending and grinding the particles in aqueous medium followed by mixing the slurry with the viscose dope, ready for spinning. The slurry preparation and grinding were carried out under different mechanical conditions, such as ball milling and ultrasonication. The evaluation of particle size of slurry was carried out under two pH conditions, first at the inherent pH (neutral pH 7) and at high pH (alkaline pH 13) equivalent to the pH of viscose dope. Furthermore, for stable slurry making, different surfactants were used. The phosphate ether-based anionic surfactant was found to effectively stabilize the dispersion better under the pH conditions used. The effect of stable slurry on good spinning was validated through an inline pressure gauge during viscose fibre spinning. To assess the IR reflecting property of viscose fibre, a direct visual evaluation was done through an IR camera, which indicated a significant increase of ~2°C surface temperature of the IR-Viscose Staple Fibre (VSF) in comparison with control VSF.

(Invited) Plasma Technology in Surface Engineering: From Super-Hydrophilic to Super-Hydrophobic Materials

Materials surface wettability is a fundamental property of a solid. Wettability plays a paramount role in the everyday applications of solid materials in many fields of science and technology. Numerous examples include advanced membranes (from water purification to biopharmaceuticals), energy storage devices, windows, raincoats, roofs, disposable diapers, microfluidics, bandages, tissue scaffolds, and bio-implants. With the continuous development of modern society, the demand for advanced functional materials with the desirable surface wettability is increasing faster than ever before. This is why precise control over surface wettability is expected to provide materials with superior properties for unprecedented applications in diverse fields.Over the past decade, conventional wet chemistry approaches have been among the most frequently used methods for surface wettability control. However, they are often energy-inefficient, pollute the environment, and rely on harsh synthesis conditions. Recently, low-temperature plasma processing has attracted major attention in surface wettability control. The reason for this particular interest is because plasma processing is highly-selective, environmentally friendly, and low-cost. Plasma processing can uniquely modify both the surface chemistry and surface topography for a wide range of materials. Moreover, it can be operated at very mild conditions such as room temperature, atmospheric pressure, and open-air environments.Plasma can be used as a controlled reactive physicochemical environment for surface activation, coating deposition, and nanostructuring of diverse materials. The unique plasma-specific conditions and effects allow precise control over microscopic surface chemical composition and surface nanostructures by adjusting the macroscopical energy input. Accordingly, effective control over surface wettability can be achieved for a broad range of hard and soft materials. An environmentally friendly, large scale and low-cost wetting control method that does not result in bulk damage, would result in improvement of industrial applications. A possible solution to this wetting control problem is atmospheric-pressure plasma (APP), especially the plasma generated in open-air due to the benefits of solvent-free treatment, requiring no vacuum systems and suitable for in-line processes. In the current work, we will give a comprehensive overview of different atmospheric pressure plasma processes capable to change the surface properties of the polymers with little or no change of the bulk. Two main approaches: (i) plasma activation introducing oxygen-containing groups into the material surface; (ii) plasma polymerization directed to the change of the surface composition will be highlighted and background will be explained.Recently our team developed a new approach based on the use of a combination of plasma activation and plasma polymerization, two different plasma techniques in a single process to achieve different surface wetting properties from hydrophilic to hydrophobic, with the high long-term stability of the coatings in water. Such a type of research approach realized in one plasma source was not yet applied for wettability control and has very promising application potential in the industrial processing of polymers. For surface engineering, and easy to scale-up the radio frequency (RF) plasma system was adopted to perform both plasma activation and plasma polymerization on PET substrate in the atmospheric pressure in the open air. Different characterization methods including WCA measurements, Fourier-transform infrared spectroscopy (FT-IR), XPS, and atomic force microscopy (AFM) were applied to get an insight into surface chemistry and morphology and the effect of the combination of the plasma activation with plasma polymerization.The developed approach has shown the capability of stable coatings deposition with the use of acrylic acid, HMDSO or fluorine-containing precursors PFDA. We demonstrate a single-step, fast, green, cheap, and universal plasma-based approach with potential for large-scale production of oil/water separation membranes, namely aerosol-assisted plasma deposition (AAPD). A hydrophobic polyester membrane is exposed to an in-line atmospheric pressure plasma coupled with an aerosol of a 2-hydroxyethyl methacrylate (HEMA) monomer. A plasma polymerized HEMA thin film is thus successfully coated on the membrane, resulting in an superhydrophilic/underwater superoleophobic surface. With created coating, the water pre-wetted plasma-functionalized polyester membrane shows an ultrahigh separation efficiency above 97.8% towards various oil/water mixtures and a superb water flux above 35.6 L m-2 s-1. Importantly, it also exhibits excellent performance in anti-oil-fouling, recyclability, and durability, indicating its high potential in real-life usage. To further examine the universality of the proposed approach, another hydrophilic monomer (acrylic acid) is also used to functionalize the polyester membranes. The obtained functionalized membranes can also efficiently separate diversified oil/water mixtures. Therefore, this study demonstrates the capability of plasma-based surface engineering methods to manipulate surface properties of materials in a very wide range from superhydrophobic to hydrophilic and even super-hydrophilic which opens new areas of applications.

87 A Low-Cost Simulator for Ultrasound-Guided Retrograde Endovascular Balloon Occlusion of the Aorta

Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) is a technique used for obtaining emergent control of life-threatening, non-compressible thoracic, abdominal, or pelvic hemorrhage (1). This abstract will detail a low-cost, ultrasound-realistic simulator for performance of the REBOA procedure. A major hurdle to widespread implementation of the REBOA technique has been the difficulty in obtaining adequate training analogues for development of competency among physicians (2). Currently, there is a paucity of literature and few commercially available simulators for REBOA training. Commercial simulation models for REBOA include high-fidelity simulators developed by Keller et al. (2), Prytime Medical (3), and Medalus (4). A low-cost, low-fidelity simulator has been proposed by Walsh et al. (5), however it lacks ultrasound compatibility. Performance of the REBOA procedure involves several steps. First, the provider must prepare a sterile field and cannulate the femoral artery with an introducer sheath under ultrasound guidance. The REBOA device is then passed through the introducer sheath to one of three target zones. Once positioned, the REBOA balloon is inflated until occlusion is achieved (1). Our simulator is constructed from a gelatin thigh analog with silicon tubing vessels connected to a clear plastic reusable simulated aorta. To create the gelatin thigh analog, two 30-cm sections of 0.5-in diameter silicon tubing are secured within an aluminum mold and embedded into a gelatin mixture. To create the gelatin, 50g of commercially available psyllium husk powder and 120g of gelatin powder (Commercial Knox Gelatin Powder(R)) are mixed in 1L of water and refrigerated for 12 hours prior to use. One of the two 0.5-in silicon tubing segments is connected to a 40-cm length of 1-in diameter rigid clear plastic tubing, which constitutes the aortic segment of the model. The aortic segment is then connected to a length of latex tubing with an in-line unidirectional manual pressure bulb to simulate pulsatile arterial flow. The other 0.5-in tubing segment is connected to an unpressurized reservoir to simulate non-pulsatile venous flow. To test the simulator, a 30-minute simulation session was conducted among 24 current emergency medicine resident physicians. Participants were asked to describe their knowledge of and confidence performing the REBOA procedure on a 1-to-5 Likert Scale before and after the simulation session. Confidence improved after the training, with a median confidence score of 1.0 before the session and 4.0 after the session. The results were evaluated using a Mann-Whitney U test which yielded a p-value <0.0001. Regarding cost, our model can be constructed for a total cost of $24. It is ultrasound compatible, provides life-like aortic pulsatility, and maintains anatomic functional accuracy. This project details the construction of a low-cost, ultrasound-compatible simulator for training physicians in the REBOA procedure. Our simulation session and subsequent review of participant data demonstrate that such a simulation exercise yielded measurable benefits in procedural skills and medical knowledge for the participants.

Plasma-aerosol-assisted surface engineering for scalable oil/water membrane separation

Oily wastewater raises worldwide concerns. Conventional remediation strategies suffer from complex and environmentally unfriendly processes. Herein, we demonstrate an efficient oil/water separation membrane prepared by a green process, namely aerosol-assisted plasma deposition. A hydrophobic polyester membrane is exposed to an in-line atmospheric pressure plasma coupled with an aerosol of a 2-hydroxyethyl methacrylate (HEMA) monomer. A plasma polymerized HEMA thin film is thus coated on the membrane, resulting in superhydrophilic/underwater superoleophobic properties. The water pre-wetted plasma-functionalized polyester membrane shows an ultrahigh separation efficiency above 97.8% towards various oil/water mixtures and a superb water flux above 35.6 L ∙ m−2∙ s−1. It also exhibits excellent performance in anti-oil-fouling, recyclability, and durability. To further examine the universality of the proposed approach, acrylic acid is also used as aerosol to functionalize the polyester membranes. The obtained functionalized membranes can also efficiently separate diversified oil/water mixtures. Furthermore, the fabrication efficiency and energy efficiency of this plasma-based surface engineering method are evaluated, which are approximately 799 cm2/h and 0.81 kW·h/m2, respectively. Therefore, this study offers a highly promising route for engineering of oil/water separation membranes helping to pave the path towards efficient oily wastewater remediation.

A pressure-resistant peripherally inserted central catheter is as useful as a central venous catheter for rapid fluid infusion: an in vitro study

BackgroundAlthough peripherally inserted central catheters (PICCs) have been widely used, they have not been frequently used in anesthesia practice. The central venous pressure measured via PICCs are reportedly as accurate as that measured via central venous catheters (CVCs), but the findings concerning rapid infusion are unclear. This study examined whether or not pressure-resistant PICCs could be used for rapid fluid infusion. MethodsThe in-line pressure was measured in similar-sized double-lumen catheters—4-Fr PICC (55, 45 and 35 cm) and 17-G CVC (20 and 13 cm)—at flow rates of saline decided using a roller pump system. We also examined the flow rate at an in-line pressure of 300 mmHg, which is the critical pressure at which hemolysis is considered to occur during blood transfusion.ResultsThe pressure-resistant PICCs obtained a high flow rate similar to that of CVCs, but the in-line pressures increased in proportion to the flow rate and catheter length. Flow rates at an intra-circuit pressure of 300 mmHg were not significantly different between the 45-cm PICC and 20-cm CVC.ConclusionPressure-resistant PICCs can be used for rapid fluid infusion.

Productivity and profitability of tomato (Solanum lycopersicum) under drip fertigation and emitter types

A field experiment was conducted during winter 2014 and 2015 in Jagatsinghpur district of Odisha to study the effect of different fertigation levels and emitter types on productivity, input use efficiency and profitability of tomato (Solanum lycopersicum L.). The three levels fertigation, i.e. recommended dose (125-75-100 kg N-P2O5-K2O/ha) of fertiliser (RDF), 80% RDF and 60% RDF and four types of emitters, viz. online pressure compensating, online nonpressure compensating, inline pressure compensating and inline non-pressure compensating drippers were tested in split-plot design with three replications. Water soluble fertilisers, viz. urea, urea phosphate with sulphate of potash and sulphate of potash were used for fertigation. The maximum fruit yield of 59.8 t/ha, water-use efficiency of 21.17 kg/m3 water, benefit:cost ratio of 3.75 and internal rate of return of 62.16% and the minimum payback period of 2.26 years were recorded in fertigation with 100% RDF through online pressure compensating emitters. Fertiliseruse efficiency increased with decrease in fertigation level and the maximum value of 270.1 kg fruit/kg of NPK was recorded with 60% RDF through online pc emitters.

Abstract 9359: Intrarenal Release of Superoxide Act Synergistically With Interstitial Angiotensin II to Promote Hypertension During Chronic Acidotic Conditions

The capacity of chronic metabolic acidosis (CMA) to evoke hypertension has been previously evaluated. The superoxide mediated oxidative stress and the activation of intrarenal angiotensin II (Ang II), demonstrated a potential role in the pathogenesis of hypertension during CMA involving renal tubular sodium retention leading to volume expansion and strain to blood vessels. The primary focus of the present study was to determine whether the superoxide and the renal angiotensin II acts either synergistically or independently of each other to promote hypertension and the underlying mechanism of superoxide generation. Male Sprague Dawley Rats (100-150gms) were divided into four groups. Chronic acidosis was induced in all 4 groups by providing free access to ammonium chloride solution (0.28M) for 8 weeks in the drinking water. The second, third, and fourth groups were injected daily with captopril (12 mg/kg/day), tempol (100μmol/kg/day) and captopril+tempol respectively. After 8 weeks, blood and urine samples were collected for pH measurements and analyzed for sodium and potassium levels. Rats were anesthetized and in-line mean arterial pressure were determined. The renal cortical tissue homogenates from all four groups were analyzed for superoxide dismutase (SOD) and NADPH oxidase (NOX2) expression. Mean arterial pressure is significantly decreased in fourth group compared to the second and third groups. The serum sodium levels in fourth group were significantly reduced compared to the separately treated second and third groups, which suggested the declined reabsorption of sodium as the cause of decreased blood pressure in the fourth group. On the other hand, there was an increased SOD activity in the fourth group compared to the second and third groups, which implied intrarenal Ang II reduces the release of superoxide by increasing its dismutation. Moreover, our results demonstrated that there were no significant alterations in phagocytic NOX2 protein levels in all four treatment groups, which indicated that the superoxide release could be due to mitochondrial oxidative stress. Overall, blocking the release of intrarenal Ang II along with promoting the superoxide dismutation, showed a potential combined effect to control the observed hypertension.

Clinical evaluation of large volume subcutaneous injection tissue effects, pain, and acceptability in healthy adults.

Determining feasibility and tolerability of large volume viscous subcutaneous injection may enable optimized, intuitive delivery system design. A translational early feasibility clinical study examined large volume subcutaneous injection viability, tolerability, acceptability, tissue effects and depot location for ~1, 8, and 20 cP injections at volumes up to 10 ml in the abdomen and 5 ml in the thigh in 32 healthy adult subjects. A commercial syringe pump system delivered 192 randomized, constant rate (20 µl/s) injections (6/subject) with in‐line injection pressure captured versus time. Deposition location was qualified via ultrasound. Tissue effects and pain tolerability were monitored through 2 hours post‐injection with corresponding Likert acceptability questionnaires administered through 72 hours. All injection conditions were feasible and well‐tolerated with ≥79.3% favorable subject responses for injection site appearance and sensation immediately post‐injection, increasing to ≥96.8% at 24 hours. Mean subject pain measured via 100 mm visual analog scale increased at needle insertion (6.9 mm, SD 10.8), peaked during injection (26.9 mm, SD 21.7) and diminished within 10 minutes post‐removal (1.9 mm, SD 4.2). Immediate injection site wheal (90.9%) and erythema (92.6%) formation was observed with progressive although incomplete resolution through 2 hours (44.6% and 11.4% remaining, respectively). Wheal resolution occurred more rapidly at lower viscosities. Most subjects (64.5%) had no preference between abdomen and thigh. Correlations between tissue effects, injection pressure and pain were weak (Pearson’s rho ± 0–0.4). The large volume injections tested, 1–20 cP viscosities up to 10 ml in the abdomen and 5 ml in the thigh, are feasible with good subject acceptability and rapid resolution of tissue effects and pain.

Distribution of in-line fluid injection pressure measurements during 40 MHz microultrasound targeted nerve injection in anaesthetised pigs

Opening pressure >138 kPa (20 psi) during intraneural injection is associated with nerve damage in dogs. The sensitivity of pressure for epineural contact lies between 90% and 97%. Our previous studies showed: (1) in Thiel embalmed soft cadavers, that opening pressure at perineural tissue, epineurium, and subepineurium had a log-normal distribution; and (2) in pigs, the fine detail of needles and nerve anatomy were visible using microultrasound.1 2 Our primary objective was to use 40 MHz microultrasound in pigs to precisely identify the tip of the needle relative to perineural tissue, epineurium, and subepineurium, and measure corresponding opening injection pressures.

Fiscal measurement and the effects of atmospheric pressure variation: Small deviations and large risks

The production and transport of liquid and gaseous hydrocarbons have always been the object of studies to improve technologies and procedures, as they involve large volumes and high-value goods. There are several procedures, rules and regulations applied to the measurement of fluid flow, but its applicability may involve significant operating costs. The balance between requirements and costs led to the use of gauge pressure transmitters instead of absolute pressure gauges and assuming a constant atmospheric pressure value for parameterization of compensation algorithms. This solution simplifies the calibration process but can potentially impact measurement uncertainties because atmospheric pressure is not constant. This work quantifies these impacts and concludes that, for gas systems operating below 2000 kPa, the use of absolute pressure transmitters or the incorporation of in-line atmospheric pressure gauges is recommended. Above this value, the effects of atmospheric pressure variation do not have as much impact, but even in these cases the final uncertainty estimate of the measured gas volume must consider this source of additional uncertainties.

Phosphorus-doped polysilicon passivating contacts deposited by atmospheric pressure chemical vapor deposition

In this work, we present a high quality tunnel oxide passivating, electron-selective contact that is formed using an in-situ phosphorus-doped polycrystalline silicon (poly-Si) layer deposited using an in-line atmospheric pressure chemical vapor deposition (APCVD) process. In-line APCVD is a single-sided deposition process that does not require vacuum systems and is well suited for high volume manufacturing. To fabricate this tunnel oxide passivating contact (TOPCon), we deposit an amorphous silicon (a-Si) layer on silicon oxide (SiO) passivated n-type crystalline silicon (c-Si) followed by an annealing step at around 910 ∘C, which provides solid phase crystallization. The contact shows an excellent surface passivation quality with an effective minority carrier lifetime of ≈4.2 ms and an implied open circuit voltage (iV ) of ≈717 mV after annealing without any additional hydrogenation process. Saturation current density (J ) of ≈18 fA cm−2 is recorded for this contact. Contact resistivity () of ≈50 mΩ·cm−2 and junction resistivity of ≈0.24 Ω·cm−2 are realized with e-beam evaporated aluminium (Al) metal contact.

Combination of real-time needle-tip pressure sensing and minimal intensity stimulation limits unintentional intraneural injection during an ultrasound-guided peripheral nerve block procedure: A randomized, parallel group, controlled trial

Study objectiveUltrasound guidance does not eliminate the risk of intraneural injection, which must be avoided during PNB. Combining ultrasound guidance (USG), nerve stimulation (NS), and injection pressure monitoring is advocated to prevent nerve injury during PNB. We hypothesized that combining patient-tailored dynamic NS and real-time pressure sensing (RTPS) could reduce the incidence of intraneural injection and nerve puncture during USG PNB compared with a traditional fixed thresholds (Control) procedure. DesignRandomized, prospective study. SettingOperating room. PatientsOne hundred ASA physical status I to III patients undergoing orthopedic surgery. InterventionsPatient anesthetized using axillary, sciatic or femoral USG PNB were randomized to the PresStim group (Dynamic RTPS and NS set at 1.5 mA then decreased; n = 50) or Control group (fixed thresholds for in-line pressure mechanical manometer and NS at 0.2 mA; n = 50). MeasurementsProcedural ultrasound images and videos were recorded, stored and reviewed in random order by two experts in ultrasound-guided PNB blinded to the group. They noted the needle-to-nerve relationship and intraneural injection for all blocked nerves. Main resultsOne hundred and twenty-three USG PNBs were performed (56 axillary brachial plexus blocks, 40 femoral nerve blocks and 27 sciatic popliteal nerve blocks); 235 blocked nerves and videos were recorded and analyzed (PresStim, 118; Control, 117). Less paresthesia was noted in the PresStim group (12.7%) compared with the Control group (18.8%). The risk of intraneural injection was significantly higher in the Control group (odds ratio [OR], 17.1; 95% confidence interval [CI], 2.2–135, P = 0.007). The risk of nerve puncture (OR, 22.7; 95% CI, 2.9–175, p = 0.003) and needle-nerve contact (OR, 4.7; 95% CI, 2.4–9.5, p < 0.001) was significantly higher in the Control group than the PresStim group. ConclusionsUnder the conditions of the study, dynamic triple monitoring combining RTPS, NS and USG decreases intraneural injection and unintentional needle-nerve contact and puncture during a PNB procedure.