A community health worker led approach to cardiovascular disease prevention in the UK-SPICES-Sussex (scaling-up packages of interventions for cardiovascular disease prevention in selected sites in Europe and Sub-saharan Africa): an implementation research project.

Background: This paper describes a UK-based study, SPICES-Sussex, which aimed to co-produce and implement a community-based cardiovascular disease (CVD) risk assessment and reduction intervention to support under-served populations at moderate risk of CVD. The objectives were to enhance stakeholder engagement; to implement the intervention in four research sites and to evaluate the use of Voluntary and Community and Social Enterprises (VCSE) and Community Health Worker (CHW) partnerships in health interventions. Methods: A type three hybrid implementation study design was used with mixed methods data. This paper represents the process evaluation of the implementation of the SPICES-Sussex Project. The evaluation was conducted using the RE-AIM framework. Results: Reach: 381 individuals took part in the risk profiling questionnaire and forty-one women, and five men participated in the coaching intervention. Effectiveness: quantitative results from intervention participants showed significant improvements in CVD behavioural risk factors across several measures. Qualitative data indicated high acceptability, with the holistic, personalised, and person-centred approach being valued by participants. Adoption: 50% of VCSEs approached took part in the SPICES programme, The CHWs felt empowered to deliver high-quality and mutually beneficial coaching within a strong project infrastructure that made use of VCSE partnerships. Implementation: Co-design meetings resulted in local adaptations being made to the intervention. 29 (63%) of participants completed the intervention. Practical issues concerned how to embed CHWs in a health service context, how to keep engaging participants, and tensions between research integrity and the needs and expectations of those in the voluntary sector. Maintenance: Several VCSEs expressed an interest in continuing the intervention after the end of the SPICES programme. Conclusion: Community-engagement approaches have the potential to have positively impact the health and wellbeing of certain groups. Furthermore, VCSEs and CHWs represent a significant untapped resource in the UK. However, more work needs to be done to understand how links between the sectors can be bridged to deliver evidence-based effective alternative preventative healthcare. Reaching vulnerable populations remains a challenge despite partnerships with VCSEs which are embedded in the community. By showing what went well and what did not, this project can guide future work in community engagement for health.

An Ultrasound Array of Emitter-Receiver Stacks for Microbubble-Based Therapy.

Most therapeutic ultrasound devices place emitters and receivers in separate locations, so that the long therapeutic pulses (>1 ms) can be emitted while receivers monitor the procedure. However, with such placement, emitters and receivers are competing for the same space, producing a trade-off between emission efficiency and reception sensitivity. Taking advantage of recent studies demonstrating that short-pulse ultrasound can be used therapeutically, we aimed to develop a device that overcomes such trade-offs. The array was composed of emitter-receiver stacks, which enabled both emission and reception from the same location. Each element was made of a lead zirconate titanate (PZT)-polyvinylidene fluoride (PVDF) stack. The PZT (frequency: 500 kHz, diameter: 16 mm) was used for emission and the PVDF (thickness: 28 µm, diameter: 16 mm) for broadband reception. 32 elements were assembled in a 3D-printed dome-shaped frame (focal length: 150 mm; [Formula: see text]-number: 1) and was tested in free-field and through an ex-vivo human skull. In free-field, the array had a 4.5 × 4.5 × 32 mm focus and produced a peak-negative pressure (PNP) of 2.12 MPa at its geometric center. The electronic steering range was ±15 mm laterally and larger than ±15 mm axially. Through the skull, the array produced a PNP of 0.63 MPa. The PVDF elements were able to localize broadband microbubble emissions across the skull. We built the first multi-element array for short-pulse and microbubble-based therapeutic applications. Stacked arrays overcome traditional trade-offs between the transmission and reception quality and have the potential to create a step change in treatment safety and efficacy.

The CombE-IDMS Alternate Potency Method for H5N1 and H5N8 Cell-Based Vaccines.

Assaying the potency of inactivated viral influenza vaccines is performed using single radial immunodiffusion, which is the globally accepted release method for potency. Under conditions of a rapidly emerging pandemic, such as the 2009 H1N1 influenza pandemic, a recognized obstacle in the delivery of vaccines to the public is the time needed for the distribution of calibrated SRID reagents (antisera and antigen standards) to vaccine manufacturers. Previously, we first described a novel streamlined MS-based assay, CombE-IDMS, which does not rely on antisera/antibodies or reference antigens, as a potential rapidly deployable alternate potency method through a comparison with SRID on adjuvanted seasonal quadrivalent vaccine cell-based (aQIVc) materials. In this report, we further demonstrate that the CombE-IDMS method can also be applied to measure the potency of pre-pandemic H5N1 and H5N8 monovalent vaccine materials, each subtype both unadjuvanted and adjuvanted, through a forced degradation study. Overall, CombE-IDMS results align with those of the gold standard SRID method on both H5N1 and H5N8 materials under conditions of thermal, pH, oxidative and freeze/thaw stress, lending further evidence for the CombE-IDMS method's suitability as an alternate assay for potency of both seasonal and pandemic influenza vaccines.

Repetitive, but Not Single, Mild Blast TBI Causes Persistent Neurological Impairments and Selective Cortical Neuronal Loss in Rats.

Exposure to repeated mild blast traumatic brain injury (mbTBI) is common in combat soldiers and the training of Special Forces. Evidence suggests that repeated exposure to a mild or subthreshold blast can cause serious and long-lasting impairments, but the mechanisms causing these symptoms are unclear. In this study, we characterise the effects of single and tightly coupled repeated mbTBI in Sprague-Dawley rats exposed to shockwaves generated using a shock tube. The primary outcomes are functional neurologic function (unconsciousness, neuroscore, weight loss, and RotaRod performance) and neuronal density in brain regions associated with sensorimotor function. Exposure to a single shockwave does not result in functional impairments or histologic injury, which is consistent with a mild or subthreshold injury. In contrast, exposure to three tightly coupled shockwaves results in unconsciousness, along with persistent neurologic impairments. Significant neuronal loss following repeated blast was observed in the motor cortex, somatosensory cortex, auditory cortex, and amygdala. Neuronal loss was not accompanied by changes in astrocyte reactivity. Our study identifies specific brain regions particularly sensitive to repeated mbTBI. The reasons for this sensitivity may include exposure to less attenuated shockwaves or proximity to tissue density transitions, and this merits further investigation. Our novel model will be useful in elucidating the mechanisms of sensitisation to injury, the temporal window of sensitivity and the evaluation of new treatments.

Electric-Field-Based Guidance for Percutaneous Catheter Vessel Crossing.

Percutaneous procedures to divert blood flow from one blood vessel to another can be performed with intravascular catheters but demand a method to align a crossing needle from one vessel to another. Fluoroscopic imaging alone is not adequate, and it is preferable to have a sensor on one catheter that detects the correct alignment of an incoming needle. This can be implemented by generating dipole electric fields from the crossing catheter which are detected by a receiving catheter in the target vessel and, thus, can calculate and display the degree of alignment, permitting the operator to rotate the crossing catheter to guarantee alignment when deploying a crossing needle. Catheters were built using this concept and evaluated in vitro. The results show that accurate alignment is achieved, and a successful crossing can be made. The concept is being further developed for further clinical evaluation.

Neuroprotection by the noble gases argon and xenon as treatments for acquired brain injury: a preclinical systematic review and meta-analysis.

BACKGROUND: The noble gases argon and xenon are potential novel neuroprotective treatments for acquired brain injuries. Xenon has already undergone early-stage clinical trials in the treatment of ischaemic brain injuries, with mixed results. Argon has yet to progress to clinical trials as a treatment for brain injury. Here, we aim to synthesise the results of preclinical studies evaluating argon and xenon as neuroprotective therapies for brain injuries. METHODS: After a systematic review of the MEDLINE and Embase databases, we carried out a pairwise and stratified meta-analysis. Heterogeneity was examined by subgroup analysis, funnel plot asymmetry, and Egger's regression. RESULTS: A total of 32 studies were identified, 14 for argon and 18 for xenon, involving measurements from 1384 animals, including murine, rat, and porcine models. Brain injury models included ischaemic brain injury after cardiac arrest (CA), neurological injury after cardiopulmonary bypass (CPB), traumatic brain injury (TBI), and ischaemic stroke. Both argon and xenon had significant (P<0.001), positive neuroprotective effect sizes. The overall effect size for argon (CA, TBI, stroke) was 18.1% (95% confidence interval [CI], 8.1-28.1%), and for xenon (CA, TBI, stroke) was 34.1% (95% CI, 24.7-43.6%). Including the CPB model, only present for xenon, the xenon effect size (CPB, CA, TBI, stroke) was 27.4% (95% CI, 11.5-43.3%). Xenon, both with and without the CPB model, was significantly (P<0.001) more protective than argon. CONCLUSIONS: These findings provide evidence to support the use of xenon and argon as neuroprotective treatments for acquired brain injuries. Current evidence suggests that xenon is more efficacious than argon overall.

Passive Cavitation Detection With a Needle Hydrophone Array.

Therapeutic ultrasound and microbubble technologies seek to drive systemically administered microbubbles into oscillations that safely manipulate tissue or release drugs. Such procedures often detect the unique acoustic emissions from microbubbles with the intention of using this feedback to control the microbubble activity. However, most sensor systems reported introduce distortions to the acoustic signal. Acoustic shockwaves, a key emission from microbubbles, are largely absent in reported recording, possibly due to the sensors being too large or too narrowband, or having strong phase distortions. Here, we built a sensor array that countered such limitations with small, broadband sensors and a low-phase distorting material. We built eight needle hydrophones with polyvinylidene fluoride (PVDF, diameter: 2 mm) then fit them into a 3-D-printed scaffold in a two-layered, staggered arrangement. Using this array, we monitored microbubbles exposed to therapeutically relevant ultrasound pulses (center frequency: 0.5 MHz, peak-rarefactional pressure: 130-597 kPa, pulselength: four cycles). Our tests revealed that the hydrophones were broadband with the best having a sensitivity of -224.8 dB ± 3.2 dB re 1 V/ µ Pa from 1 to 15 MHz. The array was able to capture shockwaves generated by microbubbles. The signal-to-noise ratio (SNR) of the array was approximately two times higher than individual hydrophones. Also, the array could localize microbubbles (-3 dB lateral resolution: 2.37 mm) and determine the cavitation threshold (between 161 and 254 kPa). Thus, the array accurately monitored and localized microbubble activities, and may be an important technological step toward better feedback control methods and safer and more effective treatments.

Quantifying contributions of natural variability and anthropogenic forcings on increased fire weather risk over the western United States.

Previous studies have identified a recent increase in wildfire activity in the western United States (WUS). However, the extent to which this trend is due to weather pattern changes dominated by natural variability versus anthropogenic warming has been unclear. Using an ensemble constructed flow analogue approach, we have employed observations to estimate vapor pressure deficit (VPD), the leading meteorological variable that controls wildfires, associated with different atmospheric circulation patterns. Our results show that for the period 1979 to 2020, variation in the atmospheric circulation explains, on average, only 32% of the observed VPD trend of 0.48 ± 0.25 hPa/decade (95% CI) over the WUS during the warm season (May to September). The remaining 68% of the upward VPD trend is likely due to anthropogenic warming. The ensemble simulations of climate models participating in the sixth phase of the Coupled Model Intercomparison Project suggest that anthropogenic forcing explains an even larger fraction of the observed VPD trend (88%) for the same period and region. These models and observational estimates likely provide a lower and an upper bound on the true impact of anthropogenic warming on the VPD trend over the WUS. During August 2020, when the August Complex "Gigafire" occurred in the WUS, anthropogenic warming likely explains 50% of the unprecedented high VPD anomalies.

Distal Re-Entry to Treat Lower Limb Chronic Total Occlusions Using a Novel Electrically Guided Re-Entry Catheter.

INTRODUCTION: Endovascular treatment of challenging infra-inguinal peripheral vascular disease is increasingly common because of new techniques and improved tools. The use of a novel electrically guided 5 F re-entry catheter is presented. By emitting a minute electrical field, detected by a target wire inserted from an opposing access, the catheter's orientation is accurately displayed to the operator, allowing precise re-entry without the need for fluoroscopic alignment. REPORT: An 84 year old man with tissue loss was treated for a long occlusion of the superficial femoral artery and tibial vessels. Successful subintimal recanalisation was achieved with the help of the ePATH re-entry catheter, restoring inline flow to the foot. CONCLUSION: This re-entry catheter benefits from an intuitive alignment method, smaller profile, and operator adjustable needle travel, making it a versatile tool for endovascular cases.

Calculating the Effect of Ribs on the Focus Quality of a Therapeutic Spherical Random Phased Array.

The overlaying rib cage is a major hindrance in treating liver tumors with high intensity focused ultrasound (HIFU). The problems caused are overheating of the ribs due to its high ultrasonic absorption capability and degradation of the ultrasound intensity distribution in the target plane. In this work, a correction method based on binarized apodization and geometric ray tracing approach was employed to avoid heating the ribs. A detailed calculation of the intensity distribution in the focus plane was undertaken to quantify and avoid the effect on HIFU beam generated by a 1-MHz 256-element random phased array after the ultrasonic beam passes through the rib cage. Focusing through the ribs was simulated for 18 different idealized ribs-array configurations and 10 anatomically correct ribs-array configurations, to show the effect of width of the ribs, intercostal spacing and the relative position of ribs and array on the quality of focus, and to identify the positions that are more effective for HIFU applications in the presence of ribs. Acoustic simulations showed that for a single focus without beam steering and for the same total acoustic power, the peak intensity at the target varies from a minimum of 211 W/cm2 to a maximum of 293 W/cm2 for a nominal acoustic input power of 15 W, whereas the side lobe level varies from 0.07 Ipeak to 0.28 Ipeak and the separation between the main lobe and side lobes varies from 2.5 mm to 6.3 mm, depending on the relative positioning of the array and ribs and the beam alignment. An increase in the side lobe level was observed by increasing the distance between the array and the ribs. The parameters of focus splitting and the deterioration of focus quality caused by the ultrasonic propagation through the ribs were quantified in various possible different clinical scenarios. In addition to idealized rib topology, anatomical realistic ribs were used to determine the focus quality of the HIFU beam when the beam is steered both in axial and transverse directions and when the transducer is positioned at different depths from the rib cage.

A PZT-PVDF Stacked Transducer for Short-Pulse Ultrasound Therapy and Monitoring.

Therapeutic ultrasound technologies using microbubbles require a feedback control system to perform the treatment in a safe and effective manner. Current feedback control technologies utilize the microbubble's acoustic emissions to adjust the treatment acoustic parameters. Typical systems use two separated transducers: one for transmission and the other for reception. However, separating the transmitter and receiver leads to foci misalignment. This limitation could be resolved by arranging the transmitter and receiver in a stacked configuration. Taking advantage of an increasing number of short-pulse-based therapeutic methods, we have constructed a lead zirconate titanate-polyvinylidene fluoride (PZT-PVDF) stacked transducer design that allows the transmission and reception of short-pulse ultrasound from the same location. Our design had a piston transmitter composed of a PZT disk (1 MHz, 12.7 mm in diameter), a backing layer, and two matching layers. A layer of PVDF ( [Formula: see text] in thickness, 12.7 mm in diameter) was placed at the front surface of the transmitter for reception. Transmission and reception from the same location were demonstrated in pulse-echo experiments where PZT transmitted a pulse and both PZT and PVDF received the echo. The echo signal received by the PVDF was [Formula: see text] shorter than the signal received by the PZT. Reception of broadband acoustic emissions using the PVDF was also demonstrated in experiments where microbubbles were exposed to ultrasound pulses. Thus, we have shown that our PZT-PVDF stack design has unique transmission and reception features that could be incorporated into a multielement array design that improves focal superimposing, transmission efficiency, and reception sensitivity.

3D synthetic aperture imaging with a therapeutic spherical random phased array for transcostal applications.

Experimental validation of a synthetic aperture imaging technique using a therapeutic random phased array is described, demonstrating the dual nature of imaging and therapy of such an array. The transducer is capable of generating both continuous wave high intensity beams for ablating the tumor and low intensity ultrasound pulses to image the target area. Pulse-echo data is collected from the elements of the phased array to obtain B-mode images of the targets. Since therapeutic arrays are optimized for therapy only with concave apertures having low f-number and large directive elements often coarsely sampled, imaging can not be performed using conventional beamforming. We show that synthetic aperture imaging is capable of processing the acquired RF data to obtain images of the field of interest. Simulations were performed to compare different synthetic aperture imaging techniques to identify the best algorithm in terms of spatial resolution. Experimental validation was performed using a 1 MHz, 256-elements, spherical random phased array with 130 mm radius of curvature. The array was integrated with a research ultrasound scanner via custom connectors to acquire raw RF data for variety of targets. Imaging was implemented using synthetic aperture beamforming to produce images of a rib phantom and ex vivo ribs. The array was shown to resolve spherical targets within ±15 mm of either side of the axis in the focal plane and obtain 3D images of the rib phantom up to ±40 mm of either side of the central axis and at a depth of 3-9 cm from the array surface. The lateral and axial full width half maximum was 1.15 mm and 2.75 mm, respectively. This study was undertaken to emphasize that both therapy and image guidance with a therapeutic random phased array is possible and such a system has the potential to address some major limitations in the existing high intensity focused ultrasound (HIFU) systems. The 3D images obtained with a therapeutic array can be used to identify and locate strong scattering objects aiding to image guidance and treatment planning of the HIFU procedure.

Xenon treatment after severe traumatic brain injury improves locomotor outcome, reduces acute neuronal loss and enhances early beneficial neuroinflammation: a randomized, blinded, controlled animal study.

BACKGROUND: Traumatic brain injury (TBI) is a major cause of morbidity and mortality, but there are no clinically proven treatments that specifically target neuronal loss and secondary injury development following TBI. In this study, we evaluate the effect of xenon treatment on functional outcome, lesion volume, neuronal loss and neuroinflammation after severe TBI in rats. METHODS: Young adult male Sprague Dawley rats were subjected to controlled cortical impact (CCI) brain trauma or sham surgery followed by treatment with either 50% xenon:25% oxygen balance nitrogen, or control gas 75% nitrogen:25% oxygen. Locomotor function was assessed using Catwalk-XT automated gait analysis at baseline and 24 h after injury. Histological outcomes were assessed following perfusion fixation at 15 min or 24 h after injury or sham procedure. RESULTS: Xenon treatment reduced lesion volume, reduced early locomotor deficits, and attenuated neuronal loss in clinically relevant cortical and subcortical areas. Xenon treatment resulted in significant increases in Iba1-positive microglia and GFAP-positive reactive astrocytes that was associated with neuronal preservation. CONCLUSIONS: Our findings demonstrate that xenon improves functional outcome and reduces neuronal loss after brain trauma in rats. Neuronal preservation was associated with a xenon-induced enhancement of microglial cell numbers and astrocyte activation, consistent with a role for early beneficial neuroinflammation in xenon's neuroprotective effect. These findings suggest that xenon may be a first-line clinical treatment for brain trauma.

Noble gas neuroprotection: xenon and argon protect against hypoxic-ischaemic injury in rat hippocampus in vitro via distinct mechanisms.

BACKGROUND: Noble gases may provide novel treatments for neurological injuries such as ischaemic and traumatic brain injury. Few studies have evaluated the complete series of noble gases under identical conditions in the same model. METHODS: We used an in vitro model of hypoxia-ischaemia to evaluate the neuroprotective properties of the series of noble gases, helium, neon, argon, krypton, and xenon. Organotypic hippocampal brain slices from mice were subjected to oxygen-glucose deprivation, and injury was quantified using propidium iodide fluorescence. RESULTS: Both xenon and argon were equally effective neuroprotectants, with 0.5 atm of xenon or argon reducing injury by 96% (P<0.0001), whereas helium, neon, and krypton were devoid of any protective effect. Neuroprotection by xenon, but not argon, was reversed by elevated glycine. CONCLUSIONS: Xenon and argon are equally effective as neuroprotectants against hypoxia-ischaemia in vitro, with both gases preventing injury development. Although xenon's neuroprotective effect may be mediated by inhibition of the N-methyl-d-aspartate receptor at the glycine site, argon acts via a different mechanism. These findings may have important implications for their clinical use as neuroprotectants.

Xenon improves long-term cognitive function, reduces neuronal loss and chronic neuroinflammation, and improves survival after traumatic brain injury in mice.

BACKGROUND: Xenon is a noble gas with neuroprotective properties that can improve short and long-term outcomes in young adult mice after controlled cortical impact. This follow-up study investigates the effects of xenon on very long-term outcomes and survival. METHODS: C57BL/6N young adult male mice (n=72) received single controlled cortical impact or sham surgery and were treated with either xenon (75% Xe:25% O2) or control gas (75% N2:25% O2). Outcomes measured were: (i) 24 h lesion volume and neurological outcome score; (ii) contextual fear conditioning at 2 weeks and 20 months; (iii) corpus callosum white matter quantification; (iv) immunohistological assessment of neuroinflammation and neuronal loss; and (v) long-term survival. RESULTS: Xenon treatment significantly reduced secondary injury (P<0.05), improved short-term vestibulomotor function (P<0.01), and prevented development of very late-onset traumatic brain injury (TBI)-related memory deficits. Xenon treatment reduced white matter loss in the contralateral corpus callosum and neuronal loss in the contralateral hippocampal CA1 and dentate gyrus areas at 20 months. Xenon's long-term neuroprotective effects were associated with a significant (P<0.05) reduction in neuroinflammation in multiple brain areas involved in associative memory, including reduction in reactive astrogliosis and microglial cell proliferation. Survival was improved significantly (P<0.05) in xenon-treated animals compared with untreated animals up to 12 months after injury. CONCLUSIONS: Xenon treatment after TBI results in very long-term improvements in clinically relevant outcomes and survival. Our findings support the idea that xenon treatment shortly after TBI may have long-term benefits in the treatment of brain trauma patients.

A Novel In Vitro Model of Blast Traumatic Brain Injury.

Traumatic brain injury is a leading cause of death and disability in military and civilian populations. Blast traumatic brain injury results from the detonation of explosive devices, however, the mechanisms that underlie the brain damage resulting from blast overpressure exposure are not entirely understood and are believed to be unique to this type of brain injury. Preclinical models are crucial tools that contribute to better understand blast-induced brain injury. A novel in vitro blast TBI model was developed using an open-ended shock tube to simulate real-life open-field blast waves modelled by the Friedlander waveform. C57BL/6N mouse organotypic hippocampal slice cultures were exposed to single shock waves and the development of injury was characterized up to 72 h using propidium iodide, a well-established fluorescent marker of cell damage that only penetrates cells with compromised cellular membranes. Propidium iodide fluorescence was significantly higher in the slices exposed to a blast wave when compared with sham slices throughout the duration of the protocol. The brain tissue injury is very reproducible and proportional to the peak overpressure of the shock wave applied.

Xenon Protects against Blast-Induced Traumatic Brain Injury in an In Vitro Model.

The aim of this study was to evaluate the neuroprotective efficacy of the inert gas xenon as a treatment for patients with blast-induced traumatic brain injury in an in vitro laboratory model. We developed a novel blast traumatic brain injury model using C57BL/6N mouse organotypic hippocampal brain-slice cultures exposed to a single shockwave, with the resulting injury quantified using propidium iodide fluorescence. A shock tube blast generator was used to simulate open field explosive blast shockwaves, modeled by the Friedlander waveform. Exposure to blast shockwave resulted in significant (p < 0.01) injury that increased with peak-overpressure and impulse of the shockwave, and which exhibited a secondary injury development up to 72 h after trauma. Blast-induced propidium iodide fluorescence overlapped with cleaved caspase-3 immunofluorescence, indicating that shock-wave-induced cell death involves apoptosis. Xenon (50% atm) applied 1 h after blast exposure reduced injury 24 h (p < 0.01), 48 h (p < 0.05), and 72 h (p < 0.001) later, compared with untreated control injury. Xenon-treated injured slices were not significantly different from uninjured sham slices at 24 h and 72 h. We demonstrate for the first time that xenon treatment after blast traumatic brain injury reduces initial injury and prevents subsequent injury development in vitro. Our findings support the idea that xenon may be a potential first-line treatment for those with blast-induced traumatic brain injury.

Simultaneous Ultrasound Therapy and Monitoring of Microbubble-Seeded Acoustic Cavitation Using a Single-Element Transducer.

Ultrasound-driven microbubble (MB) activity is used in therapeutic applications such as blood clot dissolution and targeted drug delivery. The safety and performance of these technologies are linked to the type and distribution of MB activities produced within the targeted area, but controlling and monitoring these activities in vivo and in real time has proven to be difficult. As therapeutic pulses are often milliseconds long, MB monitoring currently requires a separate transducer used in a passive reception mode. Here, we present a simple, inexpensive, integrated setup, in which a focused single-element transducer can perform ultrasound therapy and monitoring simultaneously. MBs were made to flow through a vessel-mimicking tube, placed within the transducer's focus, and were sonicated with therapeutic pulses (peak rarefactional pressure: 75-827 kPa, pulse lengths: [Formula: see text] and 20 ms). The MB-seeded acoustic emissions were captured using the same transducer. The received signals were separated from the therapeutic signal with a hybrid coupler and a high-pass filter. We discriminated the MB-generated cavitation signal from the primary acoustic field and characterized MB behavior in real time. The simplicity and versatility of our circuit could make existing single-element therapeutic transducers also act as cavitation detectors, allowing the production of compact therapeutic systems with real time monitoring capabilities.

Development of a high yielding E. coli periplasmic expression system for the production of humanized Fab' fragments.

Humanized Fab' fragments may be produced in the periplasm of Escherichia coli but can be subject to degradation by host cell proteases. In order to increase Fab' yield and reduce proteolysis we developed periplasmic protease deficient strains of E. coli. These strains lacked the protease activity of Tsp, protease III and DegP. High cell density fermentations indicated Tsp deficient strains increased productivity two fold but this increase was accompanied by premature cell lysis soon after the induction of Fab' expression. To overcome the reduction in cell viability we introduced suppressor mutations into the spr gene. The mutations partially restored the wild type phenotype of the cells. Furthermore, we coexpressed a range of periplasmic chaperone proteins with the Fab', DsbC had the most significant impact, increasing humanized Fab' production during high cell density fermentation. When DsbC coexpression was combined with a Tsp deficient spr strain we observed an increase in yield and essentially restored "wild type" cell viability. We achieved a final periplasmic yield of over 2.4g/L (final cell density OD600 105), 40 h post Fab' induction with minimal cell lysis.The data suggests that proteolysis, periplasm integrity, protein folding and disulphide bond formation are all potential limiting steps in the production of Fab' fragments in the periplasm of E. coli. In this body of work, we have addressed these limiting steps by utilizing stabilized protease deficient strains and chaperone coexpression. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 33:212-220, 2017.