Optimisation of the transmit beam parameters for generation of subharmonic signals in native and altered populations of a commercial microbubble contrast agent SonoVue®

The aim of this work was to establish the optimum acoustic characterisation approach and insonation transmit beam parameters for subharmonic signal generation with ‘native’ and ‘altered’ populations of a commonly-used microbubble contrast agent. Dynamic contrast-enhanced (DCE) ultrasound is a non-invasive method of imaging the microvasculature, typically implemented using harmonic imaging. Subharmonic imaging, in which echoes at half the fundamental frequency are detected, detects signals which are generated by the ultrasound contrast agents (UCAs) but not by tissue. However, optimal transmission parameters and furthermore, the optimum acoustic characterisation method have not been established. The subharmonic response of ‘native’ and ‘altered’ UCA, altered through decantation, was investigated at transmit centre frequencies 1.8–5 MHz and pulse lengths 1–8 cycles. The ‘altered’ UCA had reduced polydispersity (1–4 µm: 82% bubble volume), compared to ‘native’ (4–10 µm: 57% bubble volume). A custom-built narrow-band acoustic characterisation system was found to be more appropriate for acoustic characterisation compared to the commonly used broadband pulse-echo approach. Both UCA generated the highest subharmonic signal at pulse length of 3-cycles. The maximum ‘native’ subharmonic signal was generated at a transmit centre frequency of 1.9 MHz, corresponding to a subharmonic at 0.95 MHz. This optimal frequency increased in the ‘altered’ population to 2.3–2.5 MHz, bringing the subharmonic above 1 MHz and hence into a range amenable to clinical abdominal imaging transducers. The use of subharmonic signal detection coupled with a modified UCA size distribution has potential to significantly improve the quantification sensitivity and accuracy of DCE ultrasound imaging. Keywords: Ultrasound contrast agent; Acoustic characterisation; Subharmonic imagin

Climate, Vegetation, and Weathering across Space and Time in Lake Tanganyika (Tropical Eastern Africa)

Climate and vegetation influence weathering rates and processes; however, evaluating the effects of each and feedbacks between systems, has yet to be accomplished for many types of landscapes. A detailed understanding of how these processes interact to shape landscapes is particularly crucial for reconciling future scenarios of changing climate, where profound alterations to both the biosphere and geosphere are anticipated. In the tropics, ecosystem services, such as soil and water quality, are linked to both vegetation and weathering processes that form a strong control on natural resources that are the foundation of many communities’ daily subsistence. This understanding is further complicated by intensifying land-use within tropical watersheds, which decouples vegetation change from climate; it is yet unclear what the direct effects of vegetation change may be on erosion and weathering when operating independent of climate. Long term observational records tracking changes to the critical zone do not exist in tropical Africa, however, sedimentary paleo-records from lakes are often of sufficient length and resolution to record the impact of bioclimatic variability on surface processes. Here, we use a novel approach combining long (60ka) and intermediate-length (400yrs) lake sediment records along with historical repeat photography from Lake Tanganyika (Tanzania) to document changes and relationships among climate, vegetation, and weathering at multiple scales. These records illustrate that glacial-interglacial climate change did not significantly alter weathering intensity. Instead, we observe chemical and physical weathering responses only when the vegetation becomes more open beginning at the transition to the Holocene. Also, the largest change in chemical weathering intensity occurs only within the last ∼3ka. This is consistent with a major reorganization of vegetation and is directly attributable to Iron Age human activity, rather than climate. Furthermore, anthropogenic landscape alteration as early as ∼2.5ka, in addition to well-documented comparisons of historical land-use, suggest widespread responses of both chemical weathering intensity and enhanced soil erosion to human activity. This shows that changes in vegetation structure induced by anthropogenic activity, decoupled from climate change, generate a disproportionately large weathering response

A scoping review of mathematical models of Plasmodium vivax

Plasmodium vivax is one of the most geographically widespread malaria parasites in the world due to its ability to remain dormant in the human liver as hypnozoites and subsequently reactivate after the initial infection (i.e. relapse infections). More than 80% of P. vivax infections are due to hypnozoite reactivation. Mathematical modelling approaches have been widely applied to understand P. vivax dynamics and predict the impact of intervention outcomes. In this article, we provide a scoping review of mathematical models that capture P. vivax transmission dynamics published between January 1988 and May 2023 to provide a comprehensive summary of the mathematical models and techniques used to model P. vivax dynamics. We aim to assist researchers working on P. vivax transmission and other aspects of P. vivax malaria by highlighting best practices in currently published models and highlighting where future model development is required. We provide an overview of the different strategies used to incorporate the parasite's biology, use of multiple scales (within-host and population-level), superinfection, immunity, and treatment interventions. In most of the published literature, the rationale for different modelling approaches was driven by the research question at hand. Some models focus on the parasites' complicated biology, while others incorporate simplified assumptions to avoid model complexity. Overall, the existing literature on mathematical models for P. vivax encompasses various aspects of the parasite's dynamics. We recommend that future research should focus on refining how key aspects of P. vivax dynamics are modelled, including the accumulation of hypnozoite variation, the interaction between P. falciparum and P. vivax, acquisition of immunity, and recovery under superinfection

In situ cryogenic electro-optical and radiation hardness characterization of a T2SL MWIR sensor for space imaging

A Medium Wave Infrared (MWIR) image sensor developed by Teledyne e2v UK is studied for potential use in the International Mars Ice Mapper mission (I-MIM). Featuring a 640×512 array with a 15μm pixel pitch and a cutoff wavelength of 5μm, the sensor employs Ga-free InAsSb/InAs Type 2 Super Lattice (T2SL) and bariode (XBn) technologies. The study focuses on characterizing the sensor’s quantum efficiency (QE), dark current (DC), and radiation hardness under cryogenic conditions down to 130K. A system allowing in situ measurements pre- and post-irradiation was developed. The first QE measurements were conducted before and after irradiation with a 10MeV proton (p+) equivalent end-of-life fluence of 5×109 p+cm−2 and a double end-of-life fluence of 1×1010 p+cm−2 into the absorber layer, while the device was kept cryogenically cooled

Verbatim Theater: Prompting Reflection and Discussion about Healthcare Culture as a Means of Promoting Culture Change

Problem: The mistreatment of medical and nursing students and junior health professionals has been reported internationally in research and the media. Mistreatment can be embedded and normalized in hierarchical healthcare workplaces, limiting the effectiveness of policies and reporting tools to generate change; as a result, some of those who experience mistreatment later perpetuate it. We used a novel, creative approach, verbatim theater, to highlight the complexity of healthcare workplaces, encourage critical reflection, and support long-term culture change. Intervention: Verbatim theater is a theater-for-change documentary genre in which a playscript is devised using only the words spoken by informants. In 2017, 30 healthcare students and health professionals were recruited and interviewed about their experience of work and training by the multidisciplinary Sydney Arts and Health Collective using semi-structured interviews. Interview transcripts became the primary material from which the script for the verbatim theater play ‘Grace Under Pressure’ was developed. The performing arts have previously been used to develop the communication skills of health professional students; this esthetic expression of the real-life effects of healthcare workplace culture on trainees and students was implemented to stimulate consciousness of, and dialogue about, workplace mistreatment in healthcare work and training. Context: The play premiered at a major Sydney theater in October 2017, attended by the lay public and student and practicing health professionals. In November 2017, three focus groups were held with a sample of audience members comprising healthcare professionals and students. These focus groups explored the impact of the play on reflection and discussion of healthcare culture and/or promoting culture change in the health workplace. We analyzed the focus group data using theoretical thematic analysis, informed by Turner’s theory of the relation between ‘social’ and ‘esthetic’ drama to understand the impact of the play on its audience. Impact: Focus group members recognized aspects of their personal experience of professionalism, training, and workplace culture in the play, Grace Under Pressure. They reported that the play’s use of real-life stories and authentic language facilitated their critical reflection. Participants constructed some learning as ‘revelation,’ in which the play enabled them to gain significant new insight into the culture of health care and opened up discussions with colleagues. As a result, participants suggested possible remedies for unhealthy aspects of the culture, including systemic issues of bullying and harassment. A small number of participants critiqued aspects of the play they believed did not adequately reflect their experience, with some believing that the play over-emphasized workplace mistreatment. Lessons Learned: Verbatim theater is a potent method for making personal experiences of healthcare workplace and training culture more visible to lay and health professional audiences. In line with Turner’s theory, the play’s use of real-life stories and authentic language enabled recognition of systemic challenges in healthcare workplaces by training and practicing health professionals in the audience. Verbatim theater provides a means to promote awareness and discussion of difficult social issues and potential means of addressing them

ICDP Workshop on the Lake Tanganyika Scientific Drilling Project: A Late Miocene–Present Record of Climate, Rifting, and Ecosystem Evolution from the World\u27s Oldest Tropical Lake

The Neogene and Quaternary are characterized by enormous changes in global climate and environments, including global cooling and the establishment of northern high-latitude glaciers. These changes reshaped global ecosystems, including the emergence of tropical dry forests and savannahs that are found in Africa today, which in turn may have influenced the evolution of humans and their ancestors. However, despite decades of research we lack long, continuous, well-resolved records of tropical climate, ecosystem changes, and surface processes necessary to understand their interactions and influences on evolutionary processes. Lake Tanganyika, Africa, contains the most continuous, long continental climate record from the mid-Miocene (∼10 Ma) to the present anywhere in the tropics and has long been recognized as a top-priority site for scientific drilling. The lake is surrounded by the Miombo woodlands, part of the largest dry tropical biome on Earth. Lake Tanganyika also harbors incredibly diverse endemic biota and an entirely unexplored deep microbial biosphere, and it provides textbook examples of rift segmentation, fault behavior, and associated surface processes. To evaluate the interdisciplinary scientific opportunities that an ICDP drilling program at Lake Tanganyika could offer, more than 70 scientists representing 12 countries and a variety of scientific disciplines met in Dar es Salaam, Tanzania, in June 2019. The team developed key research objectives in basin evolution, source-to-sink sedimentology, organismal evolution, geomicrobiology, paleoclimatology, paleolimnology, terrestrial paleoecology, paleoanthropology, and geochronology to be addressed through scientific drilling on Lake Tanganyika. They also identified drilling targets and strategies, logistical challenges, and education and capacity building programs to be carried out through the project. Participants concluded that a drilling program at Lake Tanganyika would produce the first continuous Miocene–present record from the tropics, transforming our understanding of global environmental change, the environmental context of human origins in Africa, and providing a detailed window into the dynamics, tempo and mode of biological diversification and adaptive radiations

The Towuti Drilling Project:paleoenvironments, biological evolution, and geomicrobiology of a tropical Pacific lake

The Towuti Drilling Project (TDP) is an international research program, whose goal is to understand long-term environmental and climatic change in the tropical western Pacific, the impacts of geological and environmental changes on the biological evolution of aquatic taxa, and the geomicrobiology and biogeochemistry of metal-rich, ultramafic-hosted lake sediments through the scientific drilling of Lake Towuti, southern Sulawesi, Indonesia. Lake Towuti is a large tectonic lake at the downstream end of the Malili lake system, a chain of five highly biodiverse lakes that are among the oldest lakes in Southeast Asia. In 2015 we carried out a scientific drilling program on Lake Towuti using the International Continental Scientific Drilling Program (ICDP) Deep Lakes Drilling System (DLDS). We recovered a total of  ∼ 1018 m of core from 11 drilling sites with water depths ranging from 156 to 200 m. Recovery averaged 91.7 %, and the maximum drilling depth was 175 m below the lake floor, penetrating the entire sedimentary infill of the basin. Initial data from core and borehole logging indicate that these cores record the evolution of a highly dynamic tectonic and limnological system, with clear indications of orbital-scale climate variability during the mid- to late Pleistocene

An Agenda for Open Science in Communication

In the last 10 years, many canonical findings in the social sciences appear unreliable. This so-called “replication crisis” has spurred calls for open science practices, which aim to increase the reproducibility, replicability, and generalizability of findings. Communication research is subject to many of the same challenges that have caused low replicability in other fields. As a result, we propose an agenda for adopting open science practices in Communication, which includes the following seven suggestions: (1) publish materials, data, and code; (2) preregister studies and submit registered reports; (3) conduct replications; (4) collaborate; (5) foster open science skills; (6) implement Transparency and Openness Promotion Guidelines; and (7) incentivize open science practices. Although in our agenda we focus mostly on quantitative research, we also reflect on open science practices relevant to qualitative research. We conclude by discussing potential objections and concerns associated with open science practices

A review of a strategic roadmapping exercise to advance clinical translation of photoacoustic imaging: From current barriers to future adoption

Photoacoustic imaging (PAI), also referred to as optoacoustic imaging, has shown promise in early-stage clinical trials in a range of applications from inflammatory diseases to cancer. While the first PAI systems have recently received regulatory approvals, successful adoption of PAI technology into healthcare systems for clinical decision making must still overcome a range of barriers, from education and training to data acquisition and interpretation. The International Photoacoustic Standardisation Consortium (IPASC) undertook an community exercise in 2022 to identify and understand these barriers, then develop a roadmap of strategic plans to address them. Here, we outline the nature and scope of the barriers that were identified, along with short-, medium- and long-term community efforts required to overcome them, both within and beyond the IPASC group.This article is published as Assi, Hisham, Rui Cao, Madhura Castelino, Ben Cox, Fiona J. Gilbert, Janek Gröhl, Kurinchi Gurusamy et al. "A review of a strategic roadmapping exercise to advance clinical translation of photoacoustic imaging: from current barriers to future adoption." Photoacoustics (2023): 100539. doi: https://doi.org/10.1016/j.pacs.2023.100539. © 2023 The Authors. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)