Climate change is increasingly affecting Antarctica and the rest of the world. Urgent policy responses are needed to mitigate its associated impacts. Engagement of the Antarctic Treaty Consultative ...Meeting (ATCM), Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) and Committee for Environmental Protection (CEP) with the issue of climate change has culminated in several important meetings planned for 2023/2024. Researchers play a crucial role in the provision of the best available science to inform action by Antarctic policymakers, and the Scientific Committee on Antarctic Research (SCAR) clearly will play an important role in representing the Antarctic science community and delivering the latest science into the upcoming meetings. However, recognizing the ATCM's call for Parties and other stakeholders to bring experts to its meeting to support the work and with acknowledgement by CCAMLR and CEP of the value of including a range of scientific experts, we highlight the opportunity for and importance of researchers engaging proactively to offer further bespoke scientific support. Given the urgency of addressing climate change in Antarctica and beyond, every effort is needed from researchers and policymakers to work together to facilitate the necessary policy responses at both the national and international level.
The intravenous delivery of disease-relevant antigens (Ag) by polymeric nanoparticles (NP-Ags) has demonstrated Ag-specific immune tolerance in autoimmune and allergic disorders as well as allogeneic ...transplant rejection. NP-Ags are observed to distribute to the spleen, which has an established role in the induction of immune tolerance. However, studies have shown that the spleen is dispensable for NP-Ag-induced tolerance, suggesting significant contributions from other immunological sites. Here, we investigated the tolerogenic contributions of Kupffer cells (KCs) and liver sinusoidal endothelial cells (LSECs) to NP-Ag-induced tolerance in a mouse model of multiple sclerosis, experimental autoimmune encephalomyelitis (EAE). Intravenously delivered Ag-conjugated poly(lactide-co-glycolide) NPs (PLG-Ag) distributed largely to the liver, where they associated with both KCs and LSECs. This distribution was accompanied by CD4 T cell accumulation, clonal deletion, and PD-L1 expression by KCs and LSECs. Ex vivo co-cultures of PLG-Ag-treated KCs or LSECs with Ag-specific CD4 T cells resulted in PGE2 and IL-10 or PGE2 secretion, respectively. KC depletion and adoptive transfer experiments demonstrated that KCs were sufficient, but not necessary, to mediate PLG-Ag-induced tolerance in EAE. The durability of PLG-Ag-induced tolerance in the absence of KCs may be attributed to the distribution of PLG-Ags to LSECs, which demonstrated similar levels of PD-L1, PGE2, and T cell stimulatory ability. Collectively, these studies provide mechanistic support for the role of liver KCs and LSECs in Ag-specific tolerance for a biomaterial platform that is currently being evaluated in clinical trials.
Invasive alien species are among the primary causes of biodiversity change globally, with the risks thereof broadly understood for most regions of the world. They are similarly thought to be among ...the most significant conservation threats to Antarctica, especially as climate change proceeds in the region. However, no comprehensive, continent-wide evaluation of the risks to Antarctica posed by such species has been undertaken. Here we do so by sampling, identifying, and mapping the vascular plant propagules carried by all categories of visitors to Antarctica during the International Polar Year's first season (2007–2008) and assessing propagule establishment likelihood based on their identity and origins and on spatial variation in Antarctica's climate. For an evaluation of the situation in 2100, we use modeled climates based on the Intergovernmental Panel on Climate Change's Special Report on Emissions Scenarios Scenario A1B Nakićenović N, Swart R, eds (2000) Special Report on Emissions Scenarios: A Special Report of Working Group III of the Intergovernmental Panel on Climate Change (Cambridge University Press, Cambridge, UK). Visitors carrying seeds average 9.5 seeds per person, although as vectors, scientists carry greater propagule loads than tourists. Annual tourist numbers (∼33,054) are higher than those of scientists (∼7,085), thus tempering these differences in propagule load. Alien species establishment is currently most likely for the Western Antarctic Peninsula. Recent founder populations of several alien species in this area corroborate these findings. With climate change, risks will grow in the Antarctic Peninsula, Ross Sea, and East Antarctic coastal regions. Our evidence-based assessment demonstrates which parts of Antarctica are at growing risk from alien species that may become invasive and provides the means to mitigate this threat now and into the future as the continent's climate changes.
Background
Currently, racial disparities exist in access to genetic testing. Recent developments have helped narrow the gap in accessibility. The purpose of this study was to determine whether racial ...disparities in genetic consultation attendance and completion of genetic testing persist, and, if so, factors that contribute to under-utilization of these resources.
Methods
A single-institution retrospective review of breast patients referred for genetic counseling between 2017 and 2019 was performed. Univariate and multivariate logistic regression evaluated factors associated with genetic counseling attendance and genetic testing.
Results
A total of 596 patients were referred for genetic counseling: 433 (72.7%) white; 138 (23.2%) black; and 25 (4.2%) other or unknown. In multivariate analysis, black patients, patients without breast cancer family history, and patients without a current cancer diagnosis, classified as high risk, were significantly less likely to attend their genetics appointment (
p
= 0.010,
p
= 0.007,
p
= 0.005, respectively). Age, insurance type, distance from facility, and need for chemotherapy did not significantly impact consult completion rate. Of the patients who completed a genetic consult, 84.4% (
n
= 248) had genetic testing and 17.7% (
n
= 44) had a pathogenic variant. For patients who attended counseling, there were no significant factors that were predictive with receipt of genetic testing.
Conclusions
In this study, there was a significant association between race and attending genetic counseling. Once counseled, most patients went on to receive genetic testing, and racial disparities in testing disappeared, emphasizing the value of providing additional education about the importance and purpose of genetic testing.
•An expansive thermal model was developed for Stirling engine simulation.•Predicted model results were validated against experimental data and other models.•The new model predicted accurate and ...consistent experimental data.•Contributions of key parameters on engine performance was investigated.•Plausible approaches to engine improvements were revealed.
In this paper, comprehensive governing differential equations of Stirling engines have been developed by coupling the effect of gas leakage through the displacer gap, gas leakage into the crank case and the shuttle heat loss into the traditional model. Instantaneous pressures and temperatures of the working fluid in the engine were evaluated at same time step. The present model was deployed for the thermal simulation of the GPU-3 Stirling engine and the obtained results were robustly compared to experimental data as well as results from previous numerical models. Then, parametric studies were conducted to assess the impact of geometrical and operating parameters on the performance of Stirling engines working with helium or hydrogen. Results suggest that the modifications made in this model led to better accuracy and consistency in predicting the experimental data of the prototype engine at all speeds, compared with most previous models. It was found that there exists a minimum dimensionless gap number, for every engine pressure below which mass leakage into the compression volume may not impact the brake power and energetic efficiency of the engine. In addition, an optimum mean effective pressure was found for maximum energetic efficiency of the engine. This optimum value is higher for helium gas than for hydrogen gas. Further results indicated that the brake power and energetic efficiency of the prototype Stirling engine can be significantly improved by 30% and 18%, respectively, provided that the heater temperature is raised to 850 °C while the cooler temperature is reduced to 0 °C.
The distribution of terrestrial biodiversity within Antarctica is complex, with 16 distinct biogeographic regions (Antarctic Conservation Biogeographic Regions) currently recognised within the ...Antarctic continent, Peninsula and Scotia Arc archipelagos of the Antarctic Treaty area. Much of this diversity is endemic not only to Antarctica as a whole, but to specific regions within it. Further complexity is added by inclusion of the biodiversity found on the islands located in the Southern Ocean north of the Treaty area. Within Antarctica, scientific, logistic and tourism activities may inadvertently move organisms over potentially long distances, far beyond natural dispersal ranges. Such translocation can disrupt natural species distribution patterns and biogeography through: (1) movement of spatially restricted indigenous species to other areas of Antarctica; (2) movement of distinct populations of more generally distributed species from one area of Antarctica to another, leading to genetic homogenisation and loss of assumed local patterns of adaptation; and (3) further dispersal of introduced non-native species from one area of Antarctica to another. Species can be moved between regions in association with people and cargo, by ship, aircraft and overland travel. Movement of cargo and personnel by ship between stations located in different biogeographic regions is likely to present one of the greatest risks, particularly as coastal stations may experience similar climatic conditions, making establishment more likely. Recognising that reducing the risk of inter-regional transfer of species is a priority issue for the Antarctic Treaty Consultative Meeting, we make practical recommendations aimed at reducing this risk, including the implementation of appropriate biosecurity procedures.
•Distinct biogeographic regions have been identified across ice-free Antarctica.•Anthropogenic mixing of species may alter existing community structure and function.•Ships operating between stations in different regions present the greatest risk.•Similar climatic conditions at coastal stations may increase establishment risk.•Risks can be reduced by implementing biosecurity measures when moving between regions.
Background
Targeted axillary dissection (TAD) involves sentinel lymph node biopsy (SLNB) and excision of a biopsy-proven node marked by a clip. This study evaluates the feasibility of non-radioactive ...wireless localizers for targeted excision of clipped axillary lymph nodes.
Methods
We identified biopsy-proven, node-positive breast cancer patients treated with neoadjuvant therapy (NAT) and TAD from 2016 to 2020, and included those with a clipped node localized using SAVI SCOUT, Magseed, or RFID Tag. Primary outcome measures were (1) successful localization (ultrasound or mammographic-guided placement < 10 mm from target), and (2) retrieval of the clipped node during TAD, documented by specimen radiography or gross visualization. Secondary outcomes included rates of completion axillary lymph node dissection (cALND) and complications.
Results
Overall, 57 patients were included; 1 (1.8%) patient had no clip visible at the time of localization, and no radiographic confirmation of clip placement at the time of biopsy, and was therefore excluded. In the remaining 56 patients, localization was successful in 53 (94.6%) patients and the clipped node was retrieved during TAD in 51 (91.1%) patients. Twenty-three of 27 (85.2%) ypN0 patients were spared cALND; 3 (11.1%) patients had cALND for failed clipped node retrieval during TAD, and 1 (3.7%) for false-positive frozen section. In patients with TAD alone, the rates of axillary seroma and infection were 20.0% and 8.6%, respectively.
Conclusions
Wireless non-radioactive localizers are feasible for axillary localization after NAT, with high success rates of retrieving clipped nodes. The lack of signal decay is an advantage of these devices, allowing flexibility in timing of placement.
The assembly of colloidal nanocrystals (NCs) into superstructures with long-range translational and orientational order is sensitive to the molecular interactions between ligands bound to the NC ...surface. We illustrate how ligand coverage on colloidal PbS NCs can be exploited as a tunable parameter to direct the self-assembly of superlattices with predefined symmetry. We show that PbS NCs with dense ligand coverage assemble into face-centered cubic (fcc) superlattices whereas NCs with sparse ligand coverage assemble into body-centered cubic (bcc) superlattices which also exhibit orientational ordering of NCs in their lattice sites. Surface chemistry characterization combined with density functional theory calculations suggest that the loss of ligands occurs preferentially on {100} than on reconstructed {111} NC facets. The resulting anisotropic ligand distribution amplifies the role of NC shape in the assembly and leads to the formation of superlattices with translational and orientational order.
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