In-line Filter Research Articles

Circular Split Ring Resonator (C-SRR) Array Integrated Frequency-Notched Horn-Filtenna With Wide and Strong Rejection Band

Linear-array of circular split ring resonators (C-SRR) integrated wideband notched filtering horn antenna with very strong rejection-band is proposed in this article. The linear C-SRR array, consisting of 3-sub arrays each having 4 identical C-SRR-elements, is printed on a dielectric substrate and is integrated into the throat or waveguide-section of the standard X-band horn (Narada 641). Staggered arrangement of the multiple C-SRRs based in-line filter contributes to the wideband notch filtering response with measured rejection band (S11 < 3-dB) of 315 MHz in proposed horn-filtenna. The realized horn-filtenna yields co- and cross- polar peak gain suppression of 35.42 dB and 24.6 dB at and around the centre of notch-band (9.8 GHz) while at the pass band of the C-SRR filter, the proposed antenna inherits the impedance and radiation characteristics of the standalone horn antenna. The proposed technique is simple, easy to integrate and can be used to eliminate adjacent band noise/interference for faithful reception of data without using any additional filter section.

Abstract 16698: Cardiopulmonary Exercise Testing With an In-Line Filter During the COVID-19 Pandemic

Introduction: During maximum incremental exercise expiratory flow rates increase &gt; 10-fold and minute ventilation can exceed 100L/min, raising concern for possible spread of COVID-19 in asymptomatic patients undergoing exercise testing. Moreover, use of surgical or N95 masks that limit airflow are recognized to limit the ability to perform maximum exercise. Hypothesis: Use of an in-line filter during cardiopulmonary exercise testing is feasible and will not adversely impact measurements of exercise capacity. Methods: We conducted a proof-of-principle study in which a commercially available electrostat filter (Figure 1A), which has &gt;99.9% viral efficiency without affecting spirometry measurements during pulmonary function testing, was placed in-line, upstream of the flow meter and gas analyzer sample line for use during cardiopulmonary exercise testing. A single healthy subject completed incremental exercise with a 3 min period of unloaded exercise followed by 4-min stages of exercise at 50, 100, 150, and 200W with and without the filter in place on the same day. Mechanical dead space was 53 ml with the filter and 45 ml without. Results: In comparison to no internal filter, use of an in-line filter resulted in VO 2 measurements of 99%, 97%, 98%, and 97% during 50W, 100W, 150W, and 200W, respectively (Figure 1A). VO 2 /work slope measurements and measurements of minute ventilation were also highly consistent throughout exercise with and without use of an in-line filter (Figure 1B). Conclusions: Exercise testing is an integral part of cardiovascular care delivery. Our findings require further validation but suggest that an in-line filtration system can be utilized in an effort to reduce droplet and viral dissemination without impacting measures of cardiopulmonary performance.

Association between in-line filtration and Type I hypersensitivity reactions in pediatric oncology patients receiving intravenous etoposide

The objective of this study was to describe hypersensitivity reactions with and without the use of in-line filters during intravenous etoposide therapy in pediatric oncology patients. This was a retrospective review of all patients treated in the Division of Oncology/Hematology/Bone Marrow Transplant at British Columbia Children’s Hospital with intravenous etoposide between December 1, 2013 and February 1, 2018. Hypersensitivity reactions and anaphylaxis associated with etoposide infusions were compared over time, including 12 months prior to, 27 months during the use of, and for 12 months after the discontinuation of in-line filtration. There were 192 patients (median age 6.0 (IQR 2.8-13.0) years treated with etoposide and 486 etoposide infusions including 137 (28%) before, 261 (54%) during and 88 (18%) after use of in-line filters at our center. Twenty-six of 486 (5%) and 13/486 (3%) of infusions resulted in a type I hypersensitivity reaction and anaphylaxis, respectively. There were 2/137 (1%), 36/261 (14%) and 1/88 (1%) infusion reactions prior to, during and after in-line filter use, respectively. Infusion reactions during the in-line filter period were higher than during the pre-filter (Z = 3.978; p < 0.001) and post-filter (Z = 3.335; p < 0.001) periods of the study. These data suggest that the use of in-line filtration may be associated with increased frequency of hypersensitivity reactions to etoposide in pediatric cancer patients.

Update on the Use of Filters for Parenteral Nutrition: An ASPEN Position Paper

Intravenous in-line filters play a critical role in promoting patient safety during parenteral nutrition (PN) administration. Guidelines for using filters for PN have been issued by a number of professional organizations and manufacturers of PN components. Yet despite this guidance, filter use remains controversial. Recent changes in recommendations for filtering lipid injectable emulsions have added to confusion and created considerable variation in practice. This Position Paper aims to review past guidance regarding the filtration of PN, examine the clinical consequences of infusing particulate matter, discuss the challenges and issues related to filtration, and clarify the American Society for Parenteral and Enteral Nutrition (ASPEN) recommendations for the use of filters for PN administration. This paper was approved by the ASPEN Board of Directors.

Feasibility and Consistency of Results with Deployment of an In-Line Filter for Exercise-Based Evaluations of Patients With Heart Failure During the Novel Coronavirus Disease-2019 Pandemic

BackgroundExercise testing plays an important role in evaluating heart failure prognosis and selecting patients for advanced therapeutic interventions. However, concern for severe acute respiratory syndrome novel coronavirus-2 transmission during exercise testing has markedly curtailed performance of exercise testing during the novel coronavirus disease-2019 pandemic. Methods and ResultsTo examine the feasibility to conducting exercise testing with an in-line filter, 2 healthy volunteer subjects each completed 2 incremental exercise tests, one with discrete stages of increasing resistance and one with a continuous ramp. Each subject performed 1 test with an electrostatic filter in-line with the system measuring gas exchange and air flow, and 1 test without the filter in place. Oxygen uptake and minute ventilation were highly consistent when evaluated with and without use of an electrostatic filter with a >99.9% viral efficiency. ConclusionsDeployment of a commercially available in-line electrostatic viral filter during cardiopulmonary exercise testing is feasible and provides consistent data compared with testing without a filter.

Comparison of two non-specific flow-through sequential extraction approaches to identify the physico-chemical partitioning of potentially harmful elements in a certified reference material

Two non-specific sequential extraction methods utilising chemometric data processing (chemometric identification of substrates and element distribution, CISED) have been developed and used to determine the physico-chemical partitioning of potentially harmful elements (PHE) in certified reference material BCR CRM 701 (lake sediment). A miniaturized centrifugation method in which the sample was extracted on a filter insert in a polypropylene centrifuging tube, and a quasi-flow through method in which the sample was supported on a TX40 filter in a 47 mm in-line polycarbonate filter holder, gave similar results. The CISED data processing identified nine components. Seven of these were of geochemical origin – two carbonate components, an Al/Fe oxide/hydroxide component, three Fe-dominated components and one Si-dominated component – while the others represented the TX40 filter blank. The overall extraction capabilities of the methods were similar to that of the well-established BCR sequential extraction (Σsteps 1–3). However, whilst the BCR extraction is operationally defined, the CISED provides information on associations between PHE and the geochemical components identified. The flow through CISED procedure has potential applications in investigating the chemical speciation of PHE associated with urban airborne particular matter.

Tunable Optical Bandpass Filter via a Microtip-Touched Tapered Optical Fiber*Supported by the National Basic Research Program of China (Grant No. 2017YFA0304502), the National Natural Science Foundation of China (Grant Nos. 11974225, 11634008, and 11974223), the Fund for Shanxi “1331 Project” Key Subjects, the Program of State Key Laboratory of Quantum Optics and Quantum Optics Devices (Grant No. KF201809), and the

We demonstrate a tunable bandpass optical filter based on a tapered optical fiber (TOF) touched by a hemispherical microfiber tip (MFT). Other than the interference and selective material absorption effects, the filter relies on the controllable and wavelength-dependent mode–mode interactions in TOF. Experimentally, a large range of tunability is realized by controlling the position of the MFT in contact with the TOF for various TOF radii, and two distinct bandpass filter mechanisms are demonstrated. The center wavelength of the bandpass filter can be tuned from 890 nm to 1000 nm, while the FWHM bandwidth can be tuned from 110 nm to 240 nm when the MFT touches the TOF in the radius range from 160 nm to 390 nm. The distinction ratio can reach 28 ± 3 dB experimentally. The combined TOF-MFT is an in-line tunable bandpass optical filter that has great application potential in optical networks and spectroscopy, and the principle could also be generalized to other integrated photonic devices.

Liquid chromatography-tandem mass spectrometric assay for TPN171 in human plasma

A simple, rapid and accurate method for quantitative analysis of a highly selective phosphodiesterase-5 inhibitor (PDE5), TPN171 by high performance liquid chromatography and tandem mass spectrometry in human plasma was proposed and validated successfully using D3-TPN171 as internal standards (ISTD). An aliquot of 100 μL of plasma was mixed with internal standard and was precipitated with acetonitrile. Gradient elution was performed on a ACQUITY HSS T3 column (50 × 2.1 mm, 1.8 μm) coupled with a ACQUITY column in-line filter at 40℃, by 5 mM ammonium acetate in water containing 0.1 % formic acid and 0.1 % formic acid in acetonitrile as the mobile phase. The total analytical run time was 3.5 min. The analyte was monitored using multiple reaction monitoring (MRM) scan in positive polarity mode. The ion transition was m/z 442.2→113.2 and 445.2→116.2 for TPN171 and D3-TPN171 respectively. The method was validated for specificity, sensitivity, precision, accuracy, and other analytical parameters. The results found were satisfactory over the linear calibration range of 1−500 ng/mL. Within-day precisions ranged from 1.8 to 7.3 %, and between-day precisions from 2.3 to 4.9 %, accuracies were 95.5–99.8 %.The validated method was successfully applied to determine the plasma concentration after oral administration of 10 mg TPN171 in six healthy volunteers.

Detection of Antimicrobial Resistance Genes in the Milk Production Environment: Impact of Host DNA and Sequencing Depth.

Over the past decades, antimicrobial resistance (AMR) has been recognized as one of the most serious threats to public health. Although originally considered a problem to human health, the emerging crisis of AMR requires a “One Health” approach, considering human, animal, and environmental reservoirs. In this regard, the extensive use of antibiotics in the livestock production systems to treat mastitis and other bacterial diseases can lead to the presence of AMR genes in bacteria that contaminate or naturally occur in milk and dairy products, thereby introducing them into the food chain. The recent development of high-throughput next-generation sequencing (NGS) technologies is improving the fast characterization of microbial communities and their functional capabilities. In this context, whole metagenome sequencing (WMS), also called shotgun metagenomic sequencing, allows the generation of a vast amount of data which can be interrogated to generate the desired evidence, including the resistome. However, the amount of host DNA poses a major challenge to metagenome analysis. Given the current absence of literature concerning the application of WMS on milk to detect the presence of AMR genes, in the present study, we evaluated the effect of different sequencing depths, host DNA depletion methods and matrices to characterize the resistome of a milk production environment. WMS was conducted on three aliquots of bulk tank milk and three aliquots of the in-line milk filter collected from a single dairy farm; a fourth aliquot of milk and milk filter was bioinformatically subsampled. Two commercially available host DNA depletion methods were applied, and metagenomic DNA was sequenced to two different sequencing depth. Milk filters proved to be the most suitable matrices to evaluate the presence of AMR genes; besides, the pre-extraction host DNA depletion method was the most efficient approach to remove host reads. To our knowledge, this is the first study to evaluate the limitations posed by the host DNA in investigating the milk resistome with a WMS approach, confirming the circulation of AMR genes in the milk production environment.

In-line evanescent-field-coupled THz bandpass mux/demux fabricated by additive layer manufacturing technology

In this research, we present the design, fabrication, and experimental validation of 3D printed bandpass filters and mux/demux elements for terahertz frequencies. The filters consist of a set of in-line polystyrene (PS) rectangular waveguides, separated by 100 µm, 200 µm, and 400 µm air gaps. The principle of operation for the proposed filters resides in coupled-mode theory. Q-factors of up to 3.4 are observed, and additionally, the experimental evidence demonstrates that the Q-factor of the filters can be improved by adding fiber elements to the design. Finally, using two independent THz broadband channels, we demonstrate the first mux/demux device based on 3D printed in-line filters for the THz range. This approach represents a fast, robust, and low-cost solution for the next generation of THz devices for communications.

Invasive mechanical ventilation using a bilevel PAP ST device in a healthy swine model.

PurposeThe Coronavirus Disease 2019 (COVID-19) pandemic may cause an acute shortage of ventilators. Standard noninvasive bilevel positive airway pressure devices with spontaneous and timed respirations (bilevel PAP ST) could provide invasive ventilation but evidence on their effectiveness in this capacity is limited. We sought to evaluate the ability of bilevel PAP ST to effect gas exchange via invasive ventilation in a healthy swine model.MethodsTwo single limb respiratory circuits with passive filtered exhalation were constructed and evaluated. Next, two bilevel PAP ST devices, designed for sleep laboratory and home use, were tested on an intubated healthy swine model using these circuits. These devices were compared to an anesthesia ventilator.ResultsWe evaluated respiratory mechanics, minute ventilation, oxygenation, and presence of rebreathing for all of these devices. Both bilevel PAP ST devices were able to control the measured parameters. There were noted differences in performance between the two devices. Despite these differences, both devices provided effective invasive ventilation by controlling minute ventilation and providing adequate oxygenation in the animal model.ConclusionsCommercially available bilevel PAP ST can provide invasive ventilation with a single limb respiratory circuit and in-line filters to control oxygenation and ventilation without significant rebreathing in a swine model. Further study is needed to evaluate safety and efficacy in clinical disease models. In the setting of a ventilator shortage during the COVID-19 pandemic, and in other resource-constrained situations, these devices may be considered as an effective alternative means for invasive ventilation.

Home PAP devices in patients infected with COVID-19.

Citation:Kryger MH, Thomas R. Home PAP devices in patients infected with COVID-19. J Clin Sleep Med. 2020;16(7):1217–1219.

985-P: Insulin Excipient Removal Is Counterbalanced by Insulin Fibril Formation

Objective: Insulin infusion pump sets are only FDA approved for 3 days as device failure often ensues from an inflammatory response driven by insulin excipients. However, removal of excipients can result in insulin fibril formation, which is more toxic than excipients alone. Our objective was to determine excipient and fibril toxicity and optimize the parameters of insulin excipient removal. Methods: A modified murine air pouch model with an inline filter removed excipients prior to insulin infusion/injection. Protein analysis by circular dichroism (CD) measured protein stability upon excipient removal. A separate analysis determined cytotoxicity for insulin fibrils in cell and tissue. These studies were also extended into a porcine model. Results: Excipient removal significantly reduced the inflammatory response in vivo. However, this resulted in a loss of insulin oligomeric state. In vitro and in vivo studies demonstrated toxicity of excipients (in vitro and in vivo) and fibrils (in vivo) (Figures 1A-D). Conclusions: These studies demonstrate that insulin excipients result in cell and tissue toxicity. Complete removal of these excipients alters protein stability. Since inflammation is minimized with removal of excipients, current studies are directed at optimizing the infusion parameters and excipient concentrations. Disclosure B. Lewis: None. A. Mulka: None. C. Kesserwan: None. D. Kreutzer: Other Relationship; Self; Abbott Laboratories, cell and molecualar tissue enginnering (cmte). U. Klueh: Research Support; Self; Abbott. Other Relationship; Self; Cell and Molecular Tissue Engineering, LLC. Funding The Leona M. and Harry B. Helmsley Charitable Trust

Rethinking respiratory function laboratories in the era of coronavirus disease 2019: Considerations for today and the day after

Rethinking respiratory function laboratories in the era of coronavirus disease 2019: Considerations for today and the day after

Experimental and Molecular Insights on Mitigation of Hydrocarbon Sieving in Niobrara Shale by CO2 Huff ‘n’ Puff

Summary In nanoporous rocks, potential size/mobility exclusion and fluid–rock interactions in nanosized pores and pore throats can turn the rock into a semipermeable membrane, blocking or hindering the passage of certain molecules while allowing other molecules to pass freely. In this work, we conducted several experiments to investigate whether CO2 can mitigate the sieving effect on the hydrocarbon molecules flowing through Niobrara samples. Molecular dynamics (MD) simulations of adsorption equilibrium with and without CO2 were performed to help understand the trends observed in the experiments. The experimental procedure includes pumping liquid binary hydrocarbon mixtures (C10 and C17) of known compositions into Niobrara samples, collecting the effluents from the samples, and analyzing the compositions of the effluents. A specialized experimental setup that uses an in-line filter as a minicore holder was built for this investigation. Niobrara samples were cored and machined into 0.5-in. diameter and 0.7-in. length minicores. Hydrocarbon mixtures were injected into the minicores, and effluents were collected periodically and analyzed using gas chromatography (GC). After observing the sieving effect of the minicores, CO2 huff ‘n’ puff was performed at 600 psi, a pressure much lower than the miscibility pressure. CO2 was injected from the production side to soak the sample for a period, then the flow of the mixture was resumed, and effluents were analyzed using GC. Experimental results show that CO2 huff ‘n’ puff in several experiments noticeably mitigated the sieving of heavier components (C17). The observed increase in the fraction of C17 in the produced fluid can be either temporary or lasting. In most experiments, temporary increases in flow rates were also observed. MD simulation results suggest that for a calcite surface in equilibrium with a binary mixture of C10 and C17, more C17 molecules adsorb on the carbonate surface than the C10 molecules. Once CO2 molecules are added to the system, CO2 displaces C10 and C17 from calcite. Thus, the experimentally observed increase in the fraction of C17 can be attributed to the release of adsorbed C17. This study suggests that surface effects play a significant role in affecting flows and compositions of fluids in tight formations. In unconventional oil reservoirs, observed enhanced recovery from CO2 huff ‘n’ puff could be partly attributed to surface effects in addition to the recognized thermodynamic interaction mechanisms.

Surgical Infection Society Guidance for Operative and Peri-Operative Care of Adult Patients Infected by the Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2).

Background: Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2)-associated viral infection (coronavirus disease 2019, COVID-19) is a virulent, contagious viral pandemic that is affecting populations worldwide. As with any airborne viral respiratory infection, surgical and non-surgical patients may be affected. Methods: Review and synthesis of pertinent English-language literature pertaining to COVID-19 infection among adult patients. Results: COVID-19 disease that requires hospitalization results in critical illness approximately 25% of the time and requires mechanical ventilation with positive airway pressure. Acute kidney injury, a marked hypercoagulable state, and sometimes myocarditis can be features of COVID-19 in addition to the characteristic severe acute lung injury. Even if not among the most seriously afflicted, older patients with medical comorbidities are both predisposed to infection and risk increased morbidity and mortality, however, all persons presenting for surgical intervention should be suspected of infection (and thus transmissibility) even if asymptomatic. Although most elective surgery has been curtailed by administrative or governmental fiat, patients will still need urgent or emergency operative intervention for time-sensitive disease processes such as malignant neoplasia or for true emergencies such as perforated viscus or traumatic injury. It is possible to provide safe surgical care for SARS-CoV-2-positive patients and minimize nosocomial transmission to healthcare workers. Conclusions: This guidance will facilitate appropriate protection of patients and staff, and maintenance of infection control measures to assist surgical personnel and facilities to prepare for COVID-19-infected adult patients requiring urgent or emergent operative intervention and to provide optimal patient care.

Pragmatic recommendations for intubating critically ill patients with suspected COVID-19.

Pragmatic recommendations for intubating critically ill patients with suspected COVID-19.

Providing Continuous Renal Replacement Therapy in Patients on Extracorporeal Membrane Oxygenation.

A 34-year-old male was admitted for respiratory failure due to H1N1 influenza. His hypoxia worsened despite maximal ventilator support and thus initiated on venovenous extracorporeal membrane oxygenation (VV-ECMO). Whereas this stabilized his respiratory and hemodynamic status, his creatinine

Active Reconfigurable Ultra-Wideband Antenna With Complementary Frequency Notched and Narrowband Response

An active reconfigurable ultra-wideband antenna exhibiting complementary frequency notched and narrowband responses is proposed in this paper. The frequency responses are achieved on a CPW fed single element printed monopole antenna loaded with a pair of split ring resonators (SRR) and PIN Diodes. The SRRs and PIN Diodes embedded on the Coplanar Waveguide (CPW) feed works as an inline filter, when activated, exhibits frequency reconfigurability by transforming a frequency notched wideband antenna into a narrowband antenna. Different biasing conditions (reverse and forward) on the loaded PIN diodes toggle between frequency-notched and narrow band response of the antenna. Prototypes are fabricated and the measured impedance and radiation characteristics are presented. This concept offers multi-antenna functionality using a single radiator without any modification or addition to the radiator geometry.

Quasi-Elliptic Waveguide Dual-Band Bandpass Filters

This article presents a novel folded configuration of dual-band filter employing TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11m</sub> dual-mode elliptical cavity resonators. The proposed side-coupled configuration leads to a significant reduction of filter footprint compared with previously reported in-line dual-band filter structures. Such configuration also facilitates cross couplings to realize advanced quasi-elliptic filter functions. The structure employs irises for both sequential and cross couplings. The limitations of bandwidth realization and spurious-free window are analyzed in detail, and new coupling structures are proposed to improve the overall in-band and out-of-band responses. All the proposed dual-band designs have low insertion loss and allow for independent control of each frequency and coupling parameter. To demonstrate the concept, two 8-pole C-band elliptical cavity dual-band filters are designed, manufactured, measured, and compared. To the best of the authors' knowledge, this is the first reported folded dual-band filter configuration based on metallic waveguide cavities.