Acoustic Separation Research Articles

Perfusion Process Intensification for Lentivirus Production Using a Novel Scale-Down Model.

Process intensification has become an important strategy to lower production costs and increase manufacturing capacities for biopharmaceutical products. In particular for the production of viral vectors like lentiviruses (LVs), the transition from (fed-)batch to perfusion processes is a key strategy to meet the increasing demands for cell and gene therapy applications. However, perfusion processes are associated with higher medium consumption. Therefore, it is necessary to develop appropriate small-scale models to reduce development costs. In this work, we present the use of the acoustic wave separation technology in combination with the Ambr 250 high throughput bioreactor system for intensified perfusion process development using stable LV producer cells. The intensified perfusion process developed in the Ambr 250 model, performed at a harvest rate of 3 vessel volumes per day (VVD) and high cell densities, resulted in a 1.4-fold higher cell-specific functional virus yield and 2.8-fold higher volumetric virus yield compared to the control process at a harvest rate of 1 VVD. The findings were verified at bench scale after optimizing the bioreactor set-up, resulting in a 1.4-fold higher cell-specific functional virus yield and 3.1-fold higher volumetric virus yield.

End-to-end underwater acoustic source separation model based on EDBG-GALR

In practical work scenarios, it is common for multiple vessels to be present in close proximity within the same water area. In such cases, the acoustic signals emitted by these vessels often overlap, causing interference and reducing the accuracy of vessel identification. This paper proposes an improved GALR end-to-end underwater acoustic source separation algorithm, with ECA-DE (Efficient Channel Attention-Deep Encoder) and Bi-GRU (Bidirectional Gated Recurrent Unit), which consists of an encoder, separation blocks, and a decoder (EDBG-GALR). Addressing the issue of GALR encoder’s limited expressiveness due to its single-layer one-dimensional convolutional layer, we introduce a new deep encoder, ECA-DE, to enhance the encoder’s capability to process temporal signals and improve the efficiency of the separator’s input. Additionally, we integrate Bi-GRU into the GALR separation block’s local modeling module to enhance the local modeling ability of sequence features, thereby reducing the model’s computational and parameter requirements. Experimental results demonstrate that the proposed EDBG-GALR method can effectively separate mixed multi-target signals into multiple single-target signals, achieving a maximum scale-invariant signal-to-noise ratio (SI-SNR) improvement of 3.32 dB and a signal distortion ratio (SDR) improvement of 3.38 dB over baseline methods. These results highlight the practical applicability of EDBG-GALR in complex underwater environments.

Improved platelet separation performance from whole blood using an acoustic fluidics system.

This study investigated the effectiveness of acoustic separation for platelet analysis in patients with non-small-cell lung cancer (NSCLC), comparing it with traditional centrifugation methods. In total, 10 patients with NSCLC and 10 healthy volunteers provided peripheral blood samples, which were processed using either acoustic separation or centrifugation to isolate platelets. The study included whole transcriptome analysis of platelets, peripheral blood mononuclear cells, and tumor tissue samples, employing hierarchical clustering and Gene Ontology analysis to explore gene expression differences. Acoustic separation proved more efficient than centrifugation in terms of platelet yield, recovery rate, and RNA yield. Gene expression profiles of platelets from patients with NSCLC showed distinct patterns compared with healthy volunteers, indicating tumor-influenced alterations. Gene Ontology analysis revealed enrichment in pathways associated with platelet activation and the tumor microenvironment. This finding indicates the potential of acoustic isolation in platelet separation and its relevance in understanding the unique gene expression profile of platelets in patients with NSCLC. The findings of this study suggested that platelets from cancer patients separated by acoustic techniques exhibited tumor-specific alterations and provided new insights into the diagnosis of cancer in platelet analysis systems in clinical practice.

Spatiotemporal evolution of molar fraction in acoustic-resonance tube filled with He-Ar mixture.

This study proposes a time-evolution method to simulate acoustic gas-mixture separation. The proposed method can calculate the separation process without any arbitrary parameters except for space and time resolutions. The molar-fraction distribution within the system during the separation can be calculated, and the results show that a large molar-fraction gradient occurs in the separation tube, while a distribution also occurs in the resonance tube. Although the simulation results for the case with a high-pressure amplitude diverge from that of the experiment during the process of the separation, the simulation results for the case with a low-pressure amplitude agree well with those of the experiment.

Ship-Radiated Noise Separation in Underwater Acoustic Environments Using a Deep Time-Domain Network

Ship-radiated noise separation is critical in both military and economic domains. However, due to the complex underwater environments with multiple noise sources and reverberation, separating ship-radiated noise poses a significant challenge. Traditionally, underwater acoustic signal separation has employed blind source separation methods based on independent component analysis. Recently, the separation of underwater acoustic signals has been approached as a deep learning problem. This involves learning the features of ship-radiated noise from training data. This paper introduces a deep time-domain network for ship-radiated noise separation by leveraging the power of parallel dilated convolution and group convolution. The separation layer employs parallel dilated convolution operations with varying expansion factors to better extract low-frequency features from the signal envelope while preserving detailed information. Additionally, we use group convolution to reduce the expansion of network size caused by parallel convolution operations, enabling the network to maintain a smaller size and computational complexity while achieving good separation performance. The proposed approach is demonstrated to be superior to the other common networks in the DeepShip dataset through comprehensive comparisons.

Abstract 7498: Acoustophoresis enriches tumor cell clusters from patients with metastatic prostate cancer

Abstract Purpose: A subset of aggressive prostate cancers (PCa) progress to invade surrounding tissue to form distant metastases by shed of circulating tumor cells (CTCs). However, due to the scarcity of CTCs among the millions of nucleated blood cells, there is an unmet need to improve CTC isolation assays. Our technique Acoustophoresis uses standing ultrasound waves in a flow-through microfluidic chamber to discriminate cells based on their size, density, and compressibility. Method: We analyzed the effectiveness of acoustophoretic circulating tumor cell (CTC) isolation from 6 mL PFA fixed red blood cell lysed blood from 12 metastatic prostate cancer patients and 20 healthy control subjects and compared it to the golden standard CellSearch. For acoustic cell separation, cells were diluted in 12 mL PBS based buffer and separated by acoustophoresis and analyzed by imaging flow cytometry using a standardized antibody panel (EpCAM, cytokeratin, CD45, CD66b, DAPI). Generally, CTCs, and clusters migrate faster than white blood cells (WBCs) when exposed to ultrasound in the microchannel during acoustophoresis and can therefore be separated from nucleated blood cells. Major findings: Our pilot study shows that acoustophoresis finds both singlets and clusters of CTCs in patients as well as aggregates of CTCs and WBCs. In total, 67 cancer cell containing cell clusters were identified. Most identified cell clusters were small, containing less than 4 cells. In addition, acoustophoresis is a label-free separation technique, and could therefore identify additional subclasses of CTCs among the detected CTCs with e.g., EpCAM low/- expression. Further, we provide extensive data for the effect of storage time on acoustophoretic separation performance for fixed prostate cancer cell line cells and WBCs. Demonstrating that sample processing can be done up to 72 hours after blood sampling. We believe this is to date the most comprehensive study of acoustic separation of CTCs in patients and control subjects. Conclusion: Label-free acoustophoresis is a potential method for future non-invasive molecular interrogation of metastatic cancers. We believe Acoustophoresis is a promising technology for CTC enrichment with the possibility to detect new subclasses of CTCs as well as cell clusters not detectable with CellSearch. CTC-clusters has previously been proposed as a promising and potent predictor to monitor progressive disease and is associated with earlier onset of metastatic disease and poor prognosis, which makes acoustophoresis ability to identify clusters of high interest. Citation Format: Cecilia Magnusson, Per Augustsson, Andreas Lenshof, Andreas Josefsson, Anders Bjartell, Yvonne Ceder, Hans Lilja, Thomas Laurell. Acoustophoresis enriches tumor cell clusters from patients with metastatic prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7498.

Acoustic separation and concentration of exosomes for nucleotide detection: ASCENDx.

Efficient isolation and analysis of exosomal biomarkers hold transformative potential in biomedical applications. However, current methods are prone to contamination and require costly consumables, expensive equipment, and skilled personnel. Here, we introduce an innovative spaceship-like disc that allows Acoustic Separation and Concentration of Exosomes and Nucleotide Detection: ASCENDx. We created ASCENDx to use acoustically driven disc rotation on a spinning droplet to generate swift separation and concentration of exosomes from patient plasma samples. Integrated plasmonic nanostars on the ASCENDx disc enable label-free detection of enriched exosomes via surface-enhanced Raman scattering. Direct detection of circulating exosomal microRNA biomarkers from patient plasma samples by the ASCENDx platform facilitated a diagnostic assay for colorectal cancer with 95.8% sensitivity and 100% specificity. ASCENDx overcomes existing limitations in exosome-based molecular diagnostics and holds a powerful position for future biomedical research, precision medicine, and point-of-care medical diagnostics.

Multi-objective optimization of continuous CHO cell clarification using acoustic wave separation

Acoustic cell clarification is an upcoming novel primary harvest technology for biopharmaceutical manufacturing. It utilizes a 3D standing acoustic wave to separate cells in the form of clusters from the cell culture fluid in a continuous fashion. In this study, multi-objective optimization was performed on the acoustic clarification of CHO cells using a CadenceTM acoustic separator (CAS). Three objectives, namely cell separation efficiency (CSE), protein recovery (PR), and residence time (RT) of harvest, were evaluated using a hybrid model approach. Next, the non-dominated sorting genetic algorithm (NSGA-II) was successfully employed for tri-objective optimization using critical process parameters, namely feed flowrate (FF), concentrate flowrate (CF), and load cell density (LCD) as the decision variables. The optimization study was performed for three different configurations of the acoustic chambers: series, series–parallel, and parallel to obtain the optimal design and set of solutions. The results of the NSGA-II algorithm revealed the relationships between CSE, PR, and RT and evaluated a tradeoff and an optimal balance between them was achieved. The series–parallel configuration was evaluated as the most optimal design, giving CSE: 80.20 %, PR: 82.61 % and RT: 10.42 mins at an LCD of 30 × 106 cells mL−1. An application study was conducted to obtain the optimal solution set at different LCDs in a single run. Further, controller studies were also performed to apply corrective actions in case of feed turbidity disturbances in order to maintain a steady state. Overall, this is the first attempt to develop a multi-objective optimization study for CHO cell clarification, and this may be utilized as a tool for simulation, design, optimization, and control of any cell harvest unit operation.

Developing cyber-physical system and digital twin for smart manufacturing: Methodology and case study of continuous clarification

Biopharmaceutical production has recently begun transitioning toward the construction of highly advanced, digitalised production facilities, as per Industry Revolution 4.0 or smart manufacturing. Clarification is the bridging step in biotherapeutics continuous production, and this study proposes a Digital twin (DT) and a cyber-physical system (CPS) for the Cadence™ Acoustic Wave Separator (CAS), that uses the novel acoustic wave separation (AWS) technology for clarification of Chinese hamster ovary (CHO) cells. While the CPS - DT serves as the core, a real-time model based on the empirical and mechanistic relationship has been implemented in tandem to present a highly reliable hybrid model so as to improve the adaptability of the model. The framework employs a distributed control system (DCS), the heart of the CPS architecture, that updates the parameters of the physical system in real-time, thereby simplifying process control. To evaluate the hybrid-model predictive control strategy in real time, three case studies were conducted, which involved introducing abrupt turbidity pulses of high, low, and multi values. The sudden deviation in the turbidity of the feed sample was controlled by adjusting the acoustic power of the chamber (the control variable). The use of the proposed controller resulted in a 5 % mean deviation from the setpoint in the first chamber, while a > 33 % mean deviation resulted in the absence of the controller. The study's outcome demonstrates the high effectiveness of hybrid model-based CPS - DT control in consistently achieving high cell separation efficiency (> 90 %) and integrating the unit operation in a continuous processing train to establish a smart manufacturing prototype for the biopharmaceutical industry.

Horizontal stiffness of masonry walls infilled frame

Walls used to fill a frame structure may serve non-load bearing (visual, acoustic or fire separation) or load bearing and stiffening functions which provide geometrical stability of a structure. They are shear walls without any vertical load from higher floors. This paper proposes an algorithm for determining stiffness of a singular frame area, taking into account standards CSA S304.1-04, FEMA 306 and FEMA 274. An attempt was made to cover all valid standards (EN 1996-1-1:2010 and prEN 1996-1-1:2017) applied for designs.

Acoustic separation and fractionation of property-distributed particles from the gas phase

Established particle fractionation techniques in gas driven processes typically are limited when facing small particles (dp < 10 µm). If the particles are also distributed in multiple of their property dimensions, fractionation becomes particularly difficult. Due to the low inertia of small particles, tailor-made fractionation and separation processes are required. The particle fractionation approach presented here utilizes a resonant acoustic field for multivariate fractionation of particles from the gas phase. The fractionation process exploits the differences in acoustic mobility of particles in a gaseous environment, which has been shown to be effective even for smaller particles. Particles with multi-dimensional distributed properties (as for instance size, shape, material, apparent density, …) can be selectively addressed and fractionated in this way. Numerical and experimental studies have been carried out for analysis of particle fractionation in a resonant ultrasonic field. The particle behaviour in acoustic waves is numerically derived and analysed. Computational fluid dynamics is used to simulate the acoustically driven gas phase behaviour and its impact on particles. In the intense resonant acoustic field secondary flow structures impact the fractionation process that will be analysed. Shadowgraphy and Schlieren experiments of the gas density variations in the acoustic field are used to validate the simulations.

Low-noise fluorescent detection of cardiac troponin I in human serum based on surface acoustic wave separation

Acute myocardial infarction (AMI) is a life-threatening disease when sudden blockage of coronary artery occurs. As the most specific biomarker, cardiac troponin I (cTnI) is usually checked separately to diagnose or eliminate AMI, and achieving the accurate detection of cTnI is of great significance to patients’ life and health. Compared with other methods, fluorescent detection has the advantages of simple operation, high sensitivity and wide applicability. However, due to the strong fluorescence interference of biological molecules in body fluids, it is often difficult to obtain high sensitivity. In order to solve this problem, in this study, surface acoustic wave separation is designed to purify the target to achieve more sensitive detection performance of fluorescent detection. Specifically, the interference of background noise is almost completely removed on a microfluidic chip by isolating microbeads through acoustic radiation force, on which the biomarkers are captured by the immobilized detection probe. And then, the concentration of cTnI in human serum is detected by the fluorescence intensity change of the isolated functionalized beads. By this way, the detection limit of our biosensor calculated by 3σ/K method is 44 pg/mL and 0.34 ng/mL in PBS buffer and human serum respectively. Finally, the reliability of this method has been validated by comparison with clinical tests from the nephelometric analyzer in hospital.

Simultaneous reconstruction of 3D non-uniform temperature and velocity fields in a furnace using a bidirectional acoustic path separation tracking method

Acoustic measurement techniques applied to furnace measurements are based on the coupling of multiple fields, such as sound, temperature, and flow. To better measure high-temperature fluids within furnaces using acoustic technology, this study establishes a physical model that separates the bidirectional propagation path of sound. Additionally, a novel nonlinear acoustic ray-tracing method is proposed that allows the simultaneous measurement of temperature and flow. The combustion process of high-temperature swirling flow in a furnace is simulated, the effective path of sound propagation is tracked, and the existence of a sound shadow zone in the low-temperature jet region of the burner is discovered. After reasonably arranging sensor positions, three-dimensional nonuniform temperature and complex flow fields are simultaneously reconstructed by combining ray tracing and nonlinear acoustic tomography. The feasibility of the method is analyzed via the error analysis of the computational fluid dynamics simulation data and the reconstructed data. The proposed method provides a solution for improving the existing acoustic measurement techniques in furnaces.

Effect of background noise on speech privacy

There is a need for speech privacy in many building environments, which is often affected by various factors such as human perception, acoustic separation of partitions, and background noise levels. Previous studies have classified speech privacy rating between spaces based on partition separation and internal noise in receiving spaces. However, the typical design process often overlooks a holistic approach to speech privacy. Green buildings, focused on sustainability, have recently gained global attention. They aim to reduce environmental impact while ensuring comfort and health for occupants through energy-efficient HVAC systems, sustainable insulation, and low emissivity glazing. Despite their benefits, energy-efficient HVAC systems can emit minimal noise levels. The low internal noise levels in green buildings can often adversely affect the speech privacy rating between spaces. The Green Building Council of Australia have recently addressed the requirement of speech privacy by introducing the need for minimum internal noise levels in the Green Star Buildings, in addition to the acoustic separation requirements between spaces. This paper aims to investigate the need for minimum internal noise levels to address the requirement of speech privacy holistically rather than addressing acoustic separation and internal noise levels as individual components of acoustic design.

Method of acoustic separation on the surface of cylindrical baffle

This paper suggests a statistically optimal near-field acoustic holography method based on the combination of plane waves and cylindrical waves, which is used for underwater cylindrical baffles. The method addresses the issue that the extraction of scattered acoustic waves from the surface of underwater cylindrical baffles requires too many measurement points in practical applications: separation of incident and dispersed sound fields and near-field measurements of sound fields at baffle surfaces.The underwater detection sound source is situated in the scatterer's far-field region, so in the actual application scenario for the surface acoustic scattering separation of the cylindrical baffle, the plane wave expansion is used to represent the surface incident acoustic wave and the cylindrical wave expansion is used to describe the scattered acoustic wave on the baffle surface. As a result, fewer expansion orders are required to describe the entire sound field on the baffle's surface. It is verified by simulation that the method is valid and efficient for near-field total sound field measurement and dispersed sound field separation of roughly cylindrical targets under underwater far-field incidence situations because the measurement holographic surface of the surface permits unlimited geometries.

Acoustic design considerations for vertical education buildings

In recent years, the design and construction of vertical (multi-story) education buildings are gaining preference over traditional single storied multi buildings precincts. This change is driven by the need to incorporate modern architectural design features, optimize spatial use, and construct sustainable, energy efficient buildings for education precincts. Vertical education precincts pose multiple acoustic design challenges, including consideration for adequate acoustic separation between noise sensitive adjacencies, noise emissions from rooftop mechanical plant to outdoor learning areas, and the provision of adequate reverberation treatment while aligning with the interior design intent. Also, with the use of cross laminated timber (CLT) gaining in popularity, this presents challenges of its own. This paper discusses typical acoustic design challenges faced while designing vertical education precincts and provides recommendations adopted to resolve each design challenge.

Pretightening stress measurement method of aero-engine fastening components based on acoustic time difference separation of the coupling layers

Accurate measurement of the pretightening stress of the fastening components in the rotor system is crucial for ensuring assembly accuracy and operational safety in aero-engines. The acoustic time difference (ATD, ultrasonic propagation time difference) of the coupling layer reduces the pretightening stress measurement accuracy of the fastening components. This paper proposes a method for measuring the pretightening stress of the fastening components of the aero-engine based on the separation of the ATD of the coupling layer. Firstly, the echo signal characteristics of the bottom surface of the fastening components are analyzed by simulation, and the influence of the coupling layer ATD on the stress measurement error isstudied. Then, based on the ultrasonic multi-layer medium propagation model, a scheme of adding a transition layer to construct the first echo is proposed. The ATD of the coupling layer is fed back by the first echo propagation time difference, and the ATD caused by the coupling layer and the stress is solved by the second echo. On this basis, the ATD separation method of the coupling layer is proposed and the pretightening stress measurement model of the fastening components based on the ATD separation of the coupling layer is established. The experimental results show that after the ATD of the coupling layer is separated, the maximum measurement error of the pretightening stress of the fastening component is reduced from 13.016 MPa to 4.738 MPa, which effectively improves the measurement accuracy.

Experimental Investigation of Sheathed Cold‐Formed Steel Sigma Studs Under Compression Loading

AbstractCold‐formed steel sections are used to form various components of low‐and medium‐rise buildings. Such sections are commonly constructed with sheathing board, providing thermal and acoustic separation between interior partitions. In contemporary projects, these sheathing boards have been used to provide bracing and increasing lateral stiffness. The strength and stiffness of sheathing‐braced structural assemblies is governed by connections between framing elements and sheathing components. This paper describes an experimental investigation of stability and strength of sheathed cold‐formed steel lipped sigma wall studs under compression loading. A total of 35 experimental tests conducted covering various parameters including, sheathing plasterboard thickness, stud and track thickness, plasterboard configuration and density. Sheathing density and thickness are found to be significant in impacting the compression strength of the sheathed cold‐formed steel lipped sigma studs. A clear pattern was noted between plasterboard material and thickness on the stability and strength of the sheathed stud. It is found that higher density boards provided the greatest restraint against buckling, as did increased thicknesses. Isolating direct loading of the sheathing, and Composite action between the stud and sheathing are shown to be significant in determining the strength and controlling limit state of the stud.

Development of a new vowel feature from coarticulation: Biomechanical modeling of rhotic vowels in Kalasha

Coarticulation is an important source of new phonological contrasts. When speakers interpret effects such as nasalization, glottalization, and rhoticization as an inherent property of a vowel, a new phonological contrast is born. Studying this process directly is challenging because most vowel systems are stable and phonological change likely follows along transitional period in which coarticulation is conventionalized beyond its mechanical basis. We examine the development of a new vowel feature by focusing on the emergence of rhotic vowels in Kalasha, an endangered Dardic (Indo-Aryan) language, using biomechanical and acoustic modeling to provide a baseline of pure rhotic coarticulation.Several features of the Kalasha rhotic vowel system are not predicted from combining muscle activation for non-rhotic vowels and bunched and retroflex approximants, including that rhotic back vowels are produced with tongue body fronting (shifting the backness contrast to principally a rounding contrast). We find that synthesized vowels that are about 30% plain vowel and 70% rhotic are optimal (i.e., they best approximate observed rhotic vowels and also balance the acoustic separation among rhotic vowels with the separation from their non-rhotic counterparts). Otherwise, dispersion is not generally observed, but the vowel that is most vulnerable to merger differs most from what would be expected from coarticulation alone.

High-throughput acoustic separation device with impedance-matched channel

High-throughput acoustic separation device with impedance-matched channel