Can Mn:PIN-PMN-PT piezocrystal replace hard piezoceramic in power ultrasonic devices?

Mn:PIN-PMN-PT piezocrystal is investigated to determine whether its enhanced energy density makes it a candidate transducer material for power ultrasonics applications. To this end, the electromechanical and vibrational characteristics of a simple configuration of a bolted Langevin transducer (BLT) and then an ultrasonic surgical device, both incorporating Mn:PIN-PMN-PT piezocrystal, are compared with the same transducer configurations incorporating a conventional hard PZT piezoceramic commonly used in high-power ultrasonic transducers. The material properties of Mn:PIN-PMN-PT are determined using a single sample characterisation technique and these are used in finite element analysis (FEA) to design and then fabricate the BLT and ultrasonic surgical device, tuned to the first and second longitudinal modes at 20 kHz respectively. FEA is similarly used for the hard PZT versions. It is found that the superior elastic compliance of Mn:PIN-PMN-PT results in a higher radial piezo-stack deformation than the hard PZT under ultrasonic excitation of the BLT. However, the resulting longitudinal displacement amplitude of the two BLTs and two ultrasonic surgical devices is found to be equal, despite the higher figure of merit (Qkeff2) of those incorporating Mn:PIN-PMN-PT. The electrical impedance is measured at increasing excitation levels to evaluate the quality factor, Q. It is found that damping in the BLT with hard PZT is negligibly affected in the excitation range considered; however, the BLT incorporating Mn:PIN-PMN-PT exhibits a large reduction in Q. These findings indicate that, for measurements in air, the advantages of the high figure of merit of the piezocrystal material are not realised in a high-power transducer due to significantly increased damping at high excitation levels. To compare the vibrational response of the two ultrasonic surgical devices, L-C electrical impedance matching was implemented to maximise the efficiency of energy transfer from the source to the transducer under load. Results suggest that similar responses occurred for the two surgical devices in cutting tests using a low strength bone mimic material. However, the Mn:PIN-PMN-PT device exhibited better performance in cutting through higher strength ex-vivo chicken femur.

Rapid Emergence and Evolution of SARS-CoV-2 Variants in Advanced HIV Infection

Previous studies have linked the evolution of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) genetic variants to persistent infections in people with immunocompromising conditions1-4, but the evolutionary processes underlying these observations are incompletely understood. Here we used high-throughput, single-genome amplification and sequencing (HT-SGS) to obtain up to ~103 SARS-CoV-2 spike gene sequences in each of 184 respiratory samples from 22 people with HIV (PWH) and 25 people without HIV (PWOH). Twelve of 22 PWH had advanced HIV infection, defined by peripheral blood CD4 T cell counts (i.e., CD4 counts) <200 cells/μL. In PWOH and PWH with CD4 counts ≥200 cells/μL, most single-genome spike sequences in each person matched one haplotype that predominated throughout the infection. By contrast, people with advanced HIV showed elevated intra-host spike diversity with a median of 46 haplotypes per person (IQR 14-114). Higher intra-host spike diversity immediately after COVID-19 symptom onset predicted longer SARS-CoV-2 RNA shedding among PWH, and intra-host spike diversity at this timepoint was significantly higher in people with advanced HIV than in PWOH. Composition of spike sequence populations in people with advanced HIV fluctuated rapidly over time, with founder sequences often replaced by groups of new haplotypes. These population-level changes were associated with a high total burden of intra-host mutations and positive selection at functionally important residues. In several cases, delayed emergence of detectable serum binding to spike was associated with positive selection for presumptive antibody-escape mutations. Taken together, our findings show remarkable intra-host genetic diversity of SARS-CoV-2 in advanced HIV infection and suggest that adaptive intra-host SARS-CoV-2 evolution in this setting may contribute to the emergence of new variants of concern (VOCs).

Effect of longitudinal-bending elliptical ultrasonic vibration assistance on electrosurgical cutting and hemostasis

Electrosurgical devices are widely used for tissue cutting and hemostasis in minimally invasive surgery (MIS) for their high precision and low trauma. However, tissue adhesion and the resulting thermal injury can cause infection and impede the wound-healing process. This paper proposes a longitudinal-bending elliptical ultrasonic vibration-assisted (EUV-A) electrosurgical cutting system that incorporates an ultrasonic vibration in the direction of the cut by introducing an elliptical motion of the surgical tip. Compared with a solely longitudinal ultrasonic vibration-assisted (UV-A) electrosurgical device, the EUV-A electrode contacts the tissue intermittently, thus allowing for a cooler cut and preventing tissue accumulation. The experimental results reveal that the EUV-A electrode demonstrates better performance than the UV-A electrode for both anti-adhesion and thermal injury through in vitro experiments in porcine samples. The tissue removal mechanism of EUV-A electrosurgical cutting is modeled to investigate its anti-adhesion effect. In addition, lower adhesion, lower temperature, and faster cutting are demonstrated through in vivo experiments in rabbit samples. Results show that the EUV-A electrode causes lower thermal injury, indicative of faster postoperative healing. Finally, efficacy of the hemostatic effect of the EUV-A electrode is demonstrated in vivo for vessels up to 3.5 mm (equivalent to that of electrocautery). The study reveals that the EUV-A electrosurgical cutting system can achieve safe tissue incision and hemostasis.

Quantum bath suppression in a superconducting circuit by immersion cooling

Quantum circuits interact with the environment via several temperature-dependent degrees of freedom. Multiple experiments to-date have shown that most properties of superconducting devices appear to plateau out at T ≈ 50 mK - far above the refrigerator base temperature. This is for example reflected in the thermal state population of qubits, in excess numbers of quasiparticles, and polarisation of surface spins - factors contributing to reduced coherence. We demonstrate how to remove this thermal constraint by operating a circuit immersed in liquid ³He. This allows to efficiently cool the decohering environment of a superconducting resonator, and we see a continuous change in measured physical quantities down to previously unexplored sub-mK temperatures. The ³He acts as a heat sink which increases the energy relaxation rate of the quantum bath coupled to the circuit a thousand times, yet the suppressed bath does not introduce additional circuit losses or noise. Such quantum bath suppression can reduce decoherence in quantum circuits and opens a route for both thermal and coherence management in quantum processors.

Post-acute phase and sequelae management of epidermal necrolysis: an international, multidisciplinary DELPHI-based consensus

BACKGROUND

Long-term sequelae are frequent and often disabling after epidermal necrolysis (Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN)). However, consensus on the modalities of management of these sequelae is lacking.

OBJECTIVES

We conducted an international multicentric DELPHI exercise to establish a multidisciplinary expert consensus to standardize recommendations regarding management of SJS/TEN sequelae.

METHODS

Participants were sent a survey via the online tool "Survey Monkey" consisting of 54 statements organized into 8 topics: general recommendations, professionals involved, skin, oral mucosa and teeth, eyes, genital area, mental health, and allergy workup. Participants evaluated the level of appropriateness of each statement on a scale of 1 (extremely inappropriate) to 9 (extremely appropriate). Results were analyzed according to the RAND/UCLA Appropriateness Method.

RESULTS

Fifty-two healthcare professionals participated. After the first round, a consensus was obtained for 100% of 54 initially proposed statements (disagreement index < 1). Among them, 50 statements were agreed upon as 'appropriate'; four statements were considered 'uncertain', and ultimately finally discarded.

CONCLUSIONS

Our DELPHI-based expert consensus should help guide physicians in conducting a prolonged multidisciplinary follow-up of sequelae in SJS-TEN.

Traditional Multiwell Plates and Petri Dishes Limit the Evaluation of the Effects of Ultrasound on Cells In Vitro

Ultrasound accelerates healing in fractured bone; however, the mechanisms responsible are poorly understood. Experimental setups and ultrasound exposures vary or are not adequately characterized across studies, resulting in inter-study variation and difficulty in concluding biological effects. This study investigated experimental variability introduced through the cell culture platform used. Continuous wave ultrasound (45 kHz; 10, 25 or 75 mW/cm², 5 min/d) was applied, using a Duoson device, to Saos-2 cells seeded in multiwell plates or Petri dishes. Pressure field and vibration quantification and finite-element modelling suggested formation of complex interference patterns, resulting in localized displacement and velocity gradients, more pronounced in multiwell plates. Cell experiments revealed lower metabolic activities in both culture platforms at higher ultrasound intensities and absence of mineralization in certain regions of multiwell plates but not in Petri dishes. Thus, the same transducer produced variable results in different cell culture platforms. Analysis on Petri dishes further revealed that higher intensities reduced vinculin expression and distorted cell morphology, while causing mitochondrial and endoplasmic reticulum damage and accumulation of cells in sub-G1 phase, leading to cell death. More defined experimental setups and reproducible ultrasound exposure systems are required to study the real effect of ultrasound on cells for development of effective ultrasound-based therapies not just limited to bone repair and regeneration.

A longitudinal-torsional mode ultrasonic needle for deep penetration into bone

This work presents a longitudinal-torsional (L-T) composite mode ultrasonic needle device for deep bone penetration. The L-T needle is a geometrically modified version of an L-mode needle whose efficacy as a prototype ultrasonic bone biopsy device has been previously demonstrated by the authors. Finite element analysis (FEA) aided in the design of the L-T needle, with the aim of maximising the achievable torsional displacement while matching the longitudinal displacement achieved by the L-mode needle. Experimental modal analysis (EMA) of the fabricated ultrasonic device was used to identify the modal parameters and validate the FEA model. Harmonic analysis then provided an insight into how the inherent nonlinearities of the high-power transducer are affected by incorporating the geometrical features that degenerate the L mode into an L-T mode. High power characterisation shows that the longitudinal displacement amplitude of the L-T mode needle is larger than that of the L-mode needle. Comparative penetration tests in fresh Wistar rat skull were evaluated by investigating cell death and cell survival. The region of statistically significant cell death was small for both devices, with the combined axial and shear motion of the L-T device causing increased osteocyte necrosis within this region. Nevertheless, the results suggest a promising environment for post-operative healing. It is shown how this technology offers a potential technique for a surgical approach to the petrous apex, an application that requires a deep penetration into bone.

Four-year follow-up from a phase 2 study of obinutuzumab, ibrutinib, and venetoclax in CLL

7540

Background: Targeted agent combinations for chronic lymphocytic leukemia (CLL) have resulted in safe regimens with improved progression-free survival (PFS) compared to chemoimmunotherapy. The optimal regimen and long-term outcomes remain unknown. We conducted a phase 2 study of obinutuzumab (OBIN), ibrutinib (IBR), and venetoclax (VEN) in relapsed/refractory (RR) and treatment-naïve (TN) CLL patients (pts) and report extended follow up on two previously reported cohorts (RR, TN 1) and a new cohort of identically treated TN pts (TN 2). Methods: Pts with TN or RR (≥1 prior treatment) CLL requiring treatment were eligible. Treatment was given for 14 28-day cycles (C). OBIN was started C1, IBR C2, and VEN C3 with standard dose escalation. Response was assessed 2 months (mos) after C14 (EOT) by iwCLL 2008 criteria. Minimal residual disease (MRD) was measured by 10-color flow cytometry with a cutoff of < 1x10-4. The primary endpoint was complete remission (CR) with undetectable MRD (uMRD) in blood and bone marrow at EOT. A sample size of 25 pts per cohort achieves 90% power to test the null hypothesis of 10% against 30% with 1-sided α of 10%. The Kaplan-Meier method was used to estimate PFS and overall survival (OS). Results: 75 pts were treated in 3 cohorts (Table). Data are as of 1/3/2022. In the TN 2 cohort, the overall response rate (ORR) at EOT was 96% (95% CI: 80-100) and CR with uMRD was 20% (95% CI: 7-41). The ORR for TN 1 and TN 2 combined was 90% (95% CI: 78-97) and CR with uMRD was 24% (95% CI: 13-38). Median follow up was 56 (0-65), 57 (7-63), and 30 (24-35) mos, respectively, for RR, TN 1, and TN 2. There were 3 deaths (RR = 1, TN 1 = 1, TN 2 = 1) and 6 disease progressions (RR = 4, TN 1 = 2, TN 2 = 0). Estimated 48-month PFS for TN 1 and RR cohorts were both 96% (95% CI: 72-99) and OS was 85% (95% CI: 60-95) and 100%, respectively. The estimated 24-month PFS and OS for TN 2 were both 96% (95% CI: 75-99). The most frequent adverse events were neutropenia (95%, 73% grade ≥3), leukopenia (95%, 45% grade ≥3), lymphopenia (93%, 40% grade ≥3), and thrombocytopenia (91%, 28% grade ≥3). The only grade ≥3 non-hematologic toxicity occurring at ≥20% was hypertension (85%, 39% grade ≥3). Atrial fibrillation occurred in 11% of pts. Conclusions: At extended follow-up, remissions remain durable after fixed duration OBIN, IBR, and VEN. The efficacy and acceptable safety justify further study and are being compared to IBR and OBIN in 2 phase 3 US cooperative group trials. Clinical trial information: NCT02427451. [Table: see text]

Stabilization of cyclic processes by slowly varying forcing

We introduce a new mathematical framework for the qualitative analysis of dynamical stability, designed particularly for finite-time processes subject to slow-timescale external influences. In particular, our approach is to treat finite-time dynamical systems in terms of a slow-fast formalism in which the slow time only exists in a bounded interval, and consider stability in the singular limit. Applying this to one-dimensional phase dynamics, we provide stability definitions somewhat analogous to the classical infinite-time definitions associated with Aleksandr Lyapunov. With this, we mathematically formalize and generalize a phase-stabilization phenomenon previously described in the physics literature for which the classical stability definitions are inapplicable and instead our new framework is required.

Incorporating direct metal laser sintered complex shaped Ti-6Al-4V components in ultrasonic surgical devices

Additive manufacturing (AM) offers opportunities to design more complex shapes of the Ti-6Al-4V parts commonly used in high-power ultrasonic surgical devices. Moreover, AM metal printing will be essential to the realization of miniature ultrasonic devices incorporating internal structures for minimally invasive surgical procedures. However, it is necessary first to verify the ultrasonic vibrational behavior of devices with three-dimensional (3D) printed metal parts. Therefore, two different prototype devices are fabricated, with CNC machined mill annealed and 3D printed Ti-6Al-4V parts. Both devices, an ultrasonic bone needle and a miniature ultrasonic scalpel, incorporate complex geometries but can be manufactured using subtractive processes so that the comparative effects of 3D printing on the vibrational performance of the devices can be elucidated. The metal microstructure is investigated through measurements of longitudinal and shear acoustic velocities and scanning electron microscopy. Comparisons of electrical impedance, frequency and modal responses, and the vibrational response at increasing levels of excitation enable evaluation of the efficacy of incorporating 3D printed Ti-6Al-4V parts. Results show that whereas the bone needle exhibited comparable vibrational responses for the measurement techniques used, the 3D printed bone cutting device exhibited a more dense modal response and developed cracks at high excitation levels.

Limits and Opportunities for Miniaturizing Ultrasonic Surgical Devices Based on a Langevin Transducer

Minimally invasive surgery offers opportunities for reduced morbidities, faster postoperative recovery, and reduced costs, and is a major focus of surgical device innovation. For ultrasonic surgical devices, which offer benefits of high precision, low force, and tissue selectivity in surgical procedures, there exist laparoscopic ultrasonic shears for minimally invasive surgeries that combine tissue cutting with vessel hemostasis and sealing functions. Another approach to laparoscopy that could enable new procedures, and increase the sites of surgeries that could be reached by an ultrasonic device, involves integrating a miniature ultrasonic tool with a flexible surgical robot. However, miniaturization presents challenges in delivering the ultrasonic vibrational energy required to cut hard and soft tissues, partly due to the concomitant small volume of piezoelectric material. This article aims to provide insights into the trade-offs between transducer size, volume of piezoceramic material, resonance frequency, and the achievable displacement amplitude of devices that, consistent with current ultrasonic surgical tools, are based on a bolted Langevin transducer (BLT) and tip. Different configurations of BLTs are studied, including a cascaded version, simple bar versions, and BLTs with different front mass geometries. Results show that a BLT with a larger number of piezoceramic rings exhibits a higher coupling coefficient [Formula: see text] but with the compromise of a lower mechanical Q and stronger nonlinear response at increasing excitation levels. Displacement amplitude is reduced considerably when a BLT is excited at a higher harmonic, where the PZT rings are maintained at a nodal plane, and the resonance frequency shift at increasing excitation levels increases significantly. The electromechanical and dynamic characteristics of a cascaded transducer excited in its third longitudinal mode (L3) are almost equivalent to a much shorter version of a BLT driven at the same frequency but in its first longitudinal mode (L1), showing that a cascaded BLT can be a realistic proxy for studying the dynamics of small BLT devices. A new figure of merit is proposed that is the product of Q , [Formula: see text], and gain, which [Formula: see text] accounts for the gain of cylindrical BLTs which is shown not to be unity. It also proves effective as it incorporates the key factors affecting the achievable displacement amplitude of a BLT, including for BLTs with gain profiles in the front mass. The order of highest to lowest amplitude of a series of six gain-profile BLTs matches the order estimated by the figure of merit. It is shown that a BLT with a stepped profile front mass can achieve displacement that has the potential to cut hard or soft tissue and exhibits the smallest shifts in resonance frequency at increasing excitation levels.

Incidence, causes and predictors of unplanned hospital readmission after percutaneous coronary intervention

Background

Unplanned hospital readmissions post-percutaneous coronary intervention (PCI) result in a significant burden to the healthcare system and adverse patient outcomes. Understanding factors associated with 30-day readmission rates may help to reduce this burden. Data linkage of clinical quality registry data with routinely collected administrative datasets may assist in overcoming resource constraints that limit collection of follow-up data but is currently under-utilised worldwide.

Objective

To determine the incidence of, and factors associated with unplanned hospital readmissions in the first 30 days following PCI.

Methods

We prospectively collected data on 28,488 patients undergoing PCI between January 2013 and December 2018, who were enrolled in a multi-centre PCI registry. Data linkage to government administrative datasets was used to determine whether patients had an unplanned readmission within 30 days of PCI, the number of admissions prior to PCI and primary reason for readmission (as recorded by the International Classification of Diseases, 10th revision, Australian modification (ICD-10-AM) diagnosis codes). Patients were then divided into 3 groups: those who had 1 or more unplanned readmissions for primarily cardiac issues, those who those who had 1 or more unplanned readmissions for primarily non-cardiac issues, and those who were not readmitted, and compared for baseline, procedural and in-hospital care characteristics.

Results

In total, 3,059 patients (10.7%) had an unplanned hospital readmission within 30 days of PCI, of which, 1,848 patients (60.4%) were readmitted for primarily cardiac diagnoses. Independent predictors of both 30-day cardiac and non-cardiac readmissions were female sex, having &gt;1 admission in the 12 months prior to PCI, acute coronary syndrome presentation, having any in-hospital complication and being discharged on an oral anticoagulant (all p&lt;0.05). A stepwise increase in readmission risk was observed with increasing number of admissions from 1 to &gt;4 admissions in the 12 months prior to PCI. Presentation with cardiogenic shock (p=0.04), having an unsuccessful PCI (p=0.02) and left ventricular systolic dysfunction (p=0.02) were independent predictors of cardiac readmissions but not non-cardiac readmissions. Conversely, age &gt;60 years (p&lt;0.001) and history of diabetes mellitus (p=0.02) were found to be independent predictors of non-cardiac readmissions only.

Conclusion

Thirty-day unplanned hospital readmissions after PCI pose a significant burden to the health system. Most readmissions are primarily due to cardiac diagnoses. The most important predictive factor for both cardiac and non-cardiac readmissions appears to be the number of hospital admissions in the 12 months prior to PCI. This is valuable information for health administrators as treatment and discharge policies, and outpatient follow-up timetables may need to be tailored to patients at high risk for readmission following PCI.

Causes of readmission post-PCI

Funding Acknowledgement

Type of funding source: None

Phase II Study of Combination Obinutuzumab, Ibrutinib, and Venetoclax in Treatment-Naïve and Relapsed or Refractory Chronic Lymphocytic Leukemia

PURPOSE

The development of highly effective targeted agents for chronic lymphocytic leukemia offers the potential for fixed-duration combinations that achieve deep remissions without cytotoxic chemotherapy.

PATIENTS AND METHODS

This phase II study tested a combination regimen of obinutuzumab, ibrutinib, and venetoclax for a total of 14 cycles in both patients with treatment-naïve (n = 25) and relapsed or refractory (n = 25) chronic lymphocytic leukemia to determine the response to therapy and safety.

RESULTS

The primary end point was the rate of complete remission with undetectable minimal residual disease by flow cytometry in both the blood and bone marrow 2 months after completion of treatment, which was 28% in both groups. The overall response rate at that time was 84% in treatment-naïve patients and 88% in relapsed or refractory patients. At that time, 67% of treatment-naïve patients and 50% of relapsed or refractory patients had undetectable minimal residual disease in both the blood and marrow. At a median follow-up of 24.2 months in treatment-naïve patients and 21.5 months in relapsed or refractory patients, the median progression-free and overall survival times were not yet reached, with only 1 patient experiencing progression and 1 death. Neutropenia and thrombocytopenia were the most frequent adverse events, followed by hypertension. Grade 3 or 4 neutropenia was experienced by 66% of patients, with more events in the relapsed or refractory cohort. There was only 1 episode of neutropenic fever. A favorable impact on both perceived and objective cognitive performance during treatment was observed.

CONCLUSION

The combination regimen of obinutuzumab, ibrutinib, and venetoclax offers time-limited treatment that results in deep remissions and is now being studied in phase III cooperative group trials.

Association between exposure to persistent organic pollutants and mercury, and glucose metabolism in two Canadian Indigenous populations

BACKGROUND

The body burden of metals and persistent organic pollutants (POPs) is particularly high in populations that rely on fish and other marine species for sustenance. This exposure has been associated with an increased risk of type 2 diabetes, but results remain contrasted.

OBJECTIVE

We studied this association in two Indigenous populations of northern Québec (Canada) with markedly different prevalences of diabetes and levels of exposure to POPs and mercury.

METHODS

As part of health surveys conducted in 2004-2009, diabetes prevalence and glucose metabolism (glucose, insulin, HOMA-IR, HOMA-B) in non-diabetic fasting adults were assessed using similar protocols in two populations: Inuit from Nunavik (n = 877) and Cree from Eeyou Istchee territory (n = 780). Blood mercury, plasma polychlorinated biphenyls (PCBs), organochlorine (OC) pesticides/metabolites and polybrominated diphenylethers (PBDEs) levels were measured in samples collected at the time of examination. Logistic and linear regressions and restricted cubic splines analyses were conducted adjusting for sex, age, waist circumference, smoking and omega-3 fatty acid content in plasma phospholipids.

RESULTS

Diabetes prevalence was higher in Cree (20%) than in Inuit (7%), whereas environmental exposure was 2 to 3-fold greater in Inuit than in Cree participants. In the range of exposure common to the two populations, we observed similar linear increases in the risk of diabetes with increasing contaminant exposure. Among Cree participants, fasting glucose was positively associated with plasma PBDE level, and HOMA-B negatively associated with concentrations of ∑PCBs, dichlorodiphenyldichloroethylene, PBDEs and ∑OC pesticides. Among Inuit participants, a trend towards reduced insulin secretion was observed in association with most contaminants, but the relation was nonlinear (greater reduction at intermediate levels of exposure). A significant increase in fasting glucose levels was observed at elevated blood mercury levels (>16 μg/L).

CONCLUSION

The observed association between POPs exposure and diabetes risk in the two populations studied should be confirmed using prospective design. Our results suggest the need for additional research on the physiopathological process through which POPs exposure may induce type 2 diabetes in these Indigenous populations.

Ultrasmall Moment Incommensurate Spin Density Wave Order Masking a Ferromagnetic Quantum Critical Point in NbFe_{2}

In the metallic magnet Nb_{1-y}Fe_{2+y}, the low temperature threshold of ferromagnetism can be investigated by varying the Fe excess y within a narrow homogeneity range. We use elastic neutron scattering to track the evolution of magnetic order from Fe-rich, ferromagnetic Nb_{0.981}Fe_{2.019} to approximately stoichiometric NbFe_{2}, in which we can, for the first time, characterize a long-wavelength spin density wave state burying a ferromagnetic quantum critical point. The associated ordering wave vector q_{SDW}=(0,0,l_{SDW}) is found to depend significantly on y and T, staying finite but decreasing as the ferromagnetic state is approached. The phase diagram follows a two-order-parameter Landau theory, for which all of the coefficients can now be determined. Our findings suggest that the emergence of spin density wave order cannot be attributed to band structure effects alone. They indicate a common microscopic origin of both types of magnetic order and provide strong constraints on related theoretical scenarios based on, e.g., quantum order by disorder.

Phase-space matching between bent Laue and flat Bragg crystals

Through phase-space analysis of Dumond diagrams for a flat Bragg crystal, a single bent Laue crystal and a monochromator consisting of double-bent Laue crystals, this work shows that it is possible to match the flat Bragg crystal to both the single-crystal and double-crystal Laue monochromators. The matched system has the advantage that the phase space of the bent crystal's output beam is much larger than that of the flat crystal, making the combined system stable. Here it is suggested that such a matched system can be used at synchrotron facilities to realize X-ray dark-field imaging, analyzer-based imaging and diffraction-enhanced imaging at beamlines using double-Laue monochromators.

P2654Impact of cultural and linguistic diversity on ischaemic time and clinical outcomes in patients undergoing percutaneous coronary intervention (PCI) for ST-elevation myocardial infarction (STEMI)

Background

Healthcare providers worldwide increasingly must face the challenge of providing care to culturally and linguistically diverse patients who may have limited proficiency in the primary working language of the country they are in. This language discordance may lead to delayed treatment and worse outcomes. The impact of limited English proficiency (LEP), in a predominantly English-speaking country like Australia, on time to reperfusion and outcomes following PCI for STEMI has not been previously studied.

Objective

Among patients undergoing PCI for STEMI, to compare baseline and procedural characteristics, time to reperfusion, and 30-day clinical outcomes in patients with LEP, compared to their English-proficient counterparts.

Method

We prospectively collected data on 7,721 patients undergoing PCI for STEMI between January 2013 and December 2017 who were enrolled in the state-wide multi-centre Victorian Cardiac Outcomes Registry. Data linkage to Department of Health administrative datasets was used to identify patients' primary spoken language. Patients who identified a language other than English as their primary spoken language were classified as having LEP. Patients' postcodes were used to identify socioeconomic status through Australian Government census data. The primary endpoint was 30-day major adverse cardiovascular events (MACE)

Results

Of the 7,721 patients included, 568 (7.4%) had LEP. Patients with LEP were more likely to be older, female, diabetic, have lower socioeconomic status and have severe renal impairment (all p<0.02). They were also more likely to present to a non-PCI capable hospital (p<0.001). Among primary PCI patients (n=5,385), symptom-to-balloon time was longer in the LEP group (237 [IQR 158–429] vs. 195 [IQR 141–326] minutes, p<0.001), driven mostly by longer symptom-to-door times (STDT) (150 [IQR 90–276] vs. 114 [IQR 75–215] minutes, p<0.001). LEP patients were also less likely to have a STDT≥120 minutes (48.8% vs. 41.7%, p-0.004). Patients with LEP had higher 30-day mortality (8.8% vs. 6.5%, p=0.04) and MACE (11.8 vs. 9.1%, p=0.04). They were also more likely to have severe left ventricular (LV) dysfunction post-STEMI (11.2% vs. 8.4%, p=0.003) and heart failure readmissions within 30 days of PCI (5.2% vs. 2.0%, p<0.001). On multivariate analysis, LEP was not an independent predictor of 30-day MACE (OR 1.27, 95% CI 0.82–1.95), but was an independent predictor of STDT≥120 minutes (OR 1.24, 95% CI 1.02–1.52).

Comparison of reperfusion times

Conclusion

Limited English-proficient patients with STEMI undergoing PCI tend to present later than their English-proficient counterparts and are more likely to have severe LV dysfunction and heart failure readmissions. LEP is an independent predictor of prolonged STDT but not 30-day MACE. This suggests that more effort needs to be placed in providing education in different languages to culturally and linguistically diverse patients, to encourage early presentation in the setting of STEMI.

Propofol use in children with allergies to egg, peanut, soybean or other legumes

Propofol is the most commonly administered intravenous agent for anaesthesia in children. However, there are concerns that the emulsified preparation may not be safe in children with an allergy to egg, peanut, soybean or other legumes. We conducted a retrospective study of children with immunologically confirmed egg, peanut, soybean or legume allergy and who underwent general anaesthesia at Princess Margaret Hospital for Children between 2005 and 2015. We extracted details regarding allergy diagnosis, each anaesthetic administered and any adverse events or signs of an allergic reaction in the peri-operative period. A convenience sample of patients without any known food allergies was identified from our prospective anaesthesia research database and acted as a control group. We identified 304 food-allergic children and 649 procedures where propofol was administered. Of these, 201 (66%) had an egg allergy, 226 (74%) had a peanut allergy, 28 (9%) had a soybean allergy and 12 (4%) had a legume allergy. These were compared with 892 allergy-free patients who were exposed to propofol. In 10 (3%) allergy patients and 124 (14%) allergy-free patients, criteria for a possible allergic reaction were met. In nine of the food-allergic children and in all the controls valid non-allergic explanations for the clinical symptoms were found. One likely mild allergic reaction was experienced by a child with a previous history of intralipid allergy. We conclude that genuine serious allergic reaction to propofol is rare and is not reliably predicted by a history of food allergy.

Interstitial lung disease in patients with common variable immunodeficiency disorders: several different pathologies?

Various reports of disease-related lung pathologies in common variable immunodeficiency disorder (CVID) patients have been published, with differing histological and high-resolution computed tomography (HRCT) findings. Data were extracted from the validated Oxford Primary Immune Deficiencies  Database (PID) database (1986-2016) on adult, sporadic CVID patients with suspected interstitial lung disease (ILD). Histology of lung biopsies was studied in relation to length of follow-up, clinical outcomes, HRCT findings and chest symptoms, to look for evidence for different pathological processes. Twenty-nine CVID patients with lung histology and/or radiological evidence of ILD were followed. After exclusions, lung biopsies from 16 patients were reanalysed for ILD. There were no well-formed granulomata, even though 10 patients had systemic, biopsy-proven granulomata in other organs. Lymphocytic infiltration without recognizable histological pattern was the most common finding, usually with another feature. On immunochemistry (n = 5), lymphocytic infiltration was due to T cells (CD4 or CD8). Only one patient showed B cell follicles with germinal centres. Interstitial inflammation was common; only four of 11 such biopsies also showed interstitial fibrosis. Outcomes were variable and not related to histology, suggesting possible different pathologies. The frequent nodules on HRCT were not correlated with histology, as there were no well-formed granulomata. Five patients were asymptomatic, so it is essential for all patients to undergo HRCT, and to biopsy if abnormal HRCT findings are seen. Internationally standardized pathology and immunochemical data are needed for longitudinal studies to determine the precise pathologies and prognoses in this severe complication of CVIDs, so that appropriate therapies may be found.

Full and Half-Wavelength Ultrasonic Percussive Drills

Ultrasonic percussive drills are a leading technology for small rock drilling applications where power and weight-on-bit are at a premium. The concept uses ultrasonic vibrations to excite an oscillatory motion in a free-mass, which then delivers impulsive blows to a drilling-bit. This is a relatively complex dynamic problem involving the transducer, the free-mass, the drilling-bit and, to a certain extent, the rock surface itself. This paper examines the performance of a full-wavelength transducer compared to a half-wavelength system, which may be more attractive due to mass and dimensional drivers. To compare the two approaches, 3-D finite-element models of the ultrasonic percussive stacks using full and half-wavelength ultrasonic transducers are created to assess delivered impulse at similar power settings. In addition, impact-induced stress levels are evaluated to optimize the design of drill tools at a range of internal spring rates before, finally, experimental drilling is conducted. The results suggest that full-wavelength systems will yield much more effective impulse but, interestingly, their actual drilling performance was only marginally better than half-wavelength equivalents.

Strategies for managing multi-patient 3D mass spectrometry imaging data

Mass spectrometry imaging (MSI) has emerged as a powerful tool in biomedical research to reveal the localization of a broad scale of compounds ranging from metabolites to proteins in diseased tissues, such as malignant tumors. MSI is most commonly used for the two-dimensional imaging of tissues from multiple patients or for the three-dimensional (3D) imaging of tissue from a single patient. These applications are potentially introducing a sampling bias on a sample or patient level, respectively. The aim of this study is therefore to investigate the consequences of sampling bias on sample representativeness and on the precision of biomarker discovery for histological grading of human bladder cancers by MSI. We therefore submitted formalin-fixed paraffin-embedded tissues from 14 bladder cancer patients with varying histological grades to 3D analysis by matrix-assisted laser desorption/ionization (MALDI) MSI. We found that, after removing 20% of the data based on novel outlier detection routines for 3D-MSI data based on the evaluation of digestion efficacy and z-directed regression, on average 33% of a sample has to be measured in order to obtain sufficient coverage of the existing biological variance within a tissue sample. SIGNIFICANCE: In this study, 3D MALDI-MSI is applied for the first time on a cohort of bladder cancer patients using formalin-fixed paraffin-embedded (FFPE) tissue of bladder cancer resections. This work portrays the reproducibility that can be achieved when employing an optimized sample preparation and subsequent data evaluation approach. Our data shows the influence of sampling bias on the variability of the results, especially for a small patient cohort. Furthermore, the presented data analysis workflow can be used by others as a 3D FFPE data-analysis pipeline working on multi-patient 3D-MSI studies.

Phase 1b study of obinutuzumab, ibrutinib, and venetoclax in relapsed and refractory chronic lymphocytic leukemia

Targeted therapies including the engineered afucosylated anti-CD20 monoclonal antibody obinutuzumab, Bruton's tyrosine kinase inhibitor ibrutinib, and B-cell lymphoma protein 2 inhibitor venetoclax have demonstrated significant clinical activity in chronic lymphocytic leukemia (CLL) and, based on their complementary mechanisms, are ideal for combination. However, combining venetoclax with other active agents raises safety concerns, as it may increase the risk for tumor lysis syndrome. To minimize this risk, we designed and implemented a fixed-duration regimen using sequentially administered obinutuzumab followed by ibrutinib (cycle 2) and venetoclax (cycle 3), for a total of fourteen 28-day cycles. This phase 1b study included 12 patients with relapsed or refractory CLL. We tested 3 dose levels of venetoclax and identified the doses of all 3 agents approved by the US Food and Drug Administration for use in the combination. Adverse events were consistent with known toxicities of the individual agents, with hematologic adverse events being most frequent. No clinically significant tumor lysis syndrome occurred. The overall response rate was 92% (95% confidence interval, 62%-100%), with 42% (5/12) achieving a complete remission or complete remission with incomplete marrow recovery. There were 6 patients with no detectable CLL in both the blood and bone marrow at the end of treatment. We found this regimen to be safe and tolerable in CLL, and capable of inducing deep responses, justifying future study in our ongoing phase 2 cohorts of relapsed or refractory and treatment-naive patients, as well as larger phase 3 trials currently in planning. This trial was registered at www.clinicaltrials.gov as #NCT02427451.

A Comparison of Two Configurations for a Dual-Resonance Cymbal Transducer

The ability to design tuned ultrasonic devices that can be operated in the same mode at two different frequencies has the potential to benefit a range of applications, such as surgical cutting procedures where the penetration through soft then hard tissues could be enhanced by switching the operating frequency. The cymbal transducer has recently been adapted to form a prototype ultrasonic surgical cutting device that operates at a single frequency. In this paper, two different methods of configuring a dual-resonance cymbal transducer are detailed. The first approach relies on transducer fabrication using different metals for the two endcaps, thereby forming a dual-resonance transducer. The second employs transducer endcaps composed from a shape memory alloy, superelastic Nitinol. The resonance frequency of the Nitinol transducer depends on the phase microstructure of the material, switchable through the temperature or stress dependence of the Nitinol endcaps. The vibration response of each transducer is measured through electrical impedance measurements and laser Doppler vibrometry, and finite-element analysis is used to show the sensitivity of transducer modal response to the fabrication processes. Through this paper, two viable dual-resonance cymbal transducers are designed and characterized and compared to illustrate the advantages and disadvantages of the two different approaches.

Modal analysis and nonlinear characterization of an airborne power ultrasonic transducer with rectangular plate radiator

Some industrial processes like particle agglomeration or food dehydration among others can be enhanced by the use of power ultrasonic technologies. These technologies are based on an airborne power ultrasonic transducer (APUT) constituted by a pre-stressed Langevin-type transducer, a mechanical amplifier and an extensive plate radiator. In order to produce the desired effects in industrial processing, the transducer has to vibrate in an extensional mode driving an extensive radiator in the desired flexural mode with high amplitude displacements. Due to the generation of these high amplitude displacements in the radiator surfaces, non-linear effects like frequency shifts, hysteresis or modal interactions, among others, may be produced in the transducer behavior. When any nonlinear effect appears, when applying power, the stability and efficiency of this ultrasonic technology decreases, and the transducer may be damaged depending on the excitation power level and the nature of the nonlinearity. In this paper, an APUT with flat rectangular radiator is presented, as the active part of an innovative system with stepped reflectors. The nonlinear behavior of the APUT has been characterized numerically and experimentally in case of the modal analysis and experimentally in the case of dynamic analysis. According to the results obtained after the experiments, no modal interactions are expected, nor do other nonlinear effects.

Experimental determination of drift and PM10 cooling tower emissions: Influence of components and operating conditions

Cooling tower emissions have become an increasingly common hazard to the environment (air polluting, ice formation and salts deposition) and to the health (Legionella disease) in the last decades. Several environmental policies have emerged in recent years limiting cooling tower emissions but they have not prevented an increasing intensity of outbreaks. Since the level of emissions depends mainly on cooling tower component design and the operating conditions, this paper deals with an experimental investigation of the amount of emissions, drift and PM₁₀, emitted by a cooling tower with different configurations (drift eliminators and distribution systems) and working under several operating conditions. This objective is met by the measurement of cooling tower source emission parameters by means of the sensitive paper technique. Secondary objectives were to contextualize the observed emission rates according to international regulations. Our measurements showed that the drift rates included in the relevant international standards are significantly higher than the obtained results (an average of 100 times higher) and hence, the environmental problems may occur. Therefore, a revision of the standards is recommended with the aim of reducing the environmental and human health impact. By changing the operating conditions and the distribution system, emissions can be reduced by 52.03% and 82% on average. In the case of drift eliminators, the difference ranges from 18.18% to 98.43% on average. As the emissions level is clearly influenced by operating conditions and components, regulation tests should be referred to default conditions. Finally, guidelines to perform emission tests and a selection criterion of components and conditions for the tested cooling tower are proposed.

The revolving door: antibiotic allergy labelling in a tertiary care centre

BACKGROUND

Patients frequently report antibiotic allergies; however, only 10% of labelled patients have a true allergy.

AIM

We investigated the documentation of antibiotic 'allergy' labels (AAL) and the effect of labelling on clinical outcomes, in a West Australian adult tertiary hospital.

METHODS

Retrospective cross-sectional analysis of patients captured in the 2013 and 2014 National Antimicrobial Prescribing Surveys was carried out. Data were collected on documented antibiotic adverse drug reactions, antibiotic cost, prescribing appropriateness, prevalence of multi-drug resistant organisms, length of stay, intensive care admission and readmissions.

RESULTS

Of the 687 patients surveyed, 278 (40%) were aged 70 or above, 365 (53%) were male and 279 (41%) were prescribed antibiotics. AAL were recorded in 122 (18%) patients and the majority were penicillin labels (n = 87; 71%). Details of AAL were documented for 80 of 141 (57%) individual allergy labels, with 61 describing allergic symptoms. Patients with beta-lactam allergy labels received fewer penicillins (P = 0.0002) and more aminoglycosides (P = 0.043) and metronidazole (P = 0.021) than patients without beta-lactam labels. Five patients received an antibiotic that was contraindicated according to their allergy status. Patients with AAL had significantly more hospital readmissions within 4 weeks (P = 0.001) and 6 months (P = 0.025) of discharge, compared with unlabelled patients. The majority (81%) of readmitted labelled patients had major infections.

CONCLUSIONS

AAL are common, but poorly documented in hospital records. Patients with AAL are significantly more likely to require alternative antibiotics and hospital readmissions. There may be a role for antibiotic allergy delabelling to mitigate the clinical and economic burdens for patients with invalid allergy labels.