Search

The role of metals in forming the primary cross-links in slug glue was investigated. Several metal-binding proteins were identified in the defensive glue produced by the slug

Over the past 60 years, scientists have strived to understand the past, present and future of the Antarctic Ice Sheet. One of the key components of this research has been the mapping of Antarctic bed topography and ice thickness parameters that are crucial for modelling ice flow and hence for predicting future ice loss and ensuing sea level rise. Supported by the Scientific Committee on Antarctic Research (SCAR), the Bedmap3 Action Group aims not only to produce new gridded maps of ice thickness and bed topography for the international scientific community, but also to standardize and make available all the geophysical survey data points used in producing the Bedmap gridded products. Here, we document the survey data used in the latest iteration, Bedmap3, incorporating and adding to all of the datasets previously used for Bedmap1 and Bedmap2, including ice-bed, surface and thickness point data from all Antarctic geophysical campaigns since the 1950s. More specifically, we describe the processes used to standardize and make these and future survey and gridded datasets accessible under the ‘Findable, Accessible, Interoperable and Reusable’ (FAIR) data principles. With the goals to make the gridding process reproducible and to allow scientists to re-use the data freely for their own analysis, we introduce the new SCAR Bedmap Data Portal (bedmap.scar.org, last access: 18 October 2022) created to provide unprecedented open access to these important datasets, through a user-friendly webmap interface. We believe that this data release will be a valuable asset to Antarctic research and will greatly extend the life cycle of the data held within it. Data are available from the UK Polar Data Centre: https://data.bas.ac.uk.

Current flood risk mapping, relying on historical observations, fails to account for increasing threat under climate change. Incorporating recent developments in inundation modelling, here we show a 26.4% (24.1–29.1%) increase in US flood risk by 2050 due to climate change alone under RCP4.5. Our national depiction of comprehensive and high-resolution flood risk estimates in the United States indicates current average annual losses of US$32.1 billion (US$30.5–33.8 billion) in 2020’s climate, which are borne disproportionately by poorer communities with a proportionally larger White population. The future increase in risk will disproportionately impact Black communities, while remaining concentrated on the Atlantic and Gulf coasts. Furthermore, projected population change (SSP2) could cause flood risk increases that outweigh the impact of climate change fourfold. These results make clear the need for adaptation to flood and emergent climate risks in the United States, with mitigation required to prevent the acceleration of these risks.

A recent surge of interest in microRNA has been driven by its discovery as a circulating biomarker of disease, with many diagnostic test platforms currently under development. Alternatives to widely used microRNA quantification methods such as quantitative reverse transcriptase PCR (qRT-PCR) are needed for use in portable and point-of-care devices which are incompatible with complex sample processing workflows and thermal cycling. Rolling circle amplification (RCA) is a one-pot assay technique which directly amplifies nucleic acids using sequence-specific microRNA priming to initiate a single-step isothermal reaction that is compatible with simple devices. Sensitivity remains a limitation of RCA methods, however, and detection limits do not typically reach the femtomolar level in which microRNA targets are present in blood. RCA assays have previously been improved by digestion of the amplification products using a nicking endonuclease to exponentially generate new reaction primers. Here we describe how a ligation-free version of this technique performed in a single tube can be used to improve the limit of detection for microRNA-375, an important blood biomarker for prostate cancer. Endonuclease addition changes a linear process into an exponential amplification reaction which results in a 61-fold improvement of the limit of detection (5.9 fM), a dynamic range wider than 5-log(10), and a shorter reaction time. By eliminating the need for microRNA reverse transcription and thermal cycling, this single-step one-pot method provides a more rapid and simplified alternative to qRT-PCR for ultrasensitive microRNA quantification in blood extracts.

Psychological scientists have long taken two approaches to combatting mistaken identifications: the system-variable approach and the estimator-variable approach. The system-variable approach involves developing lineups that prevent mistaken identifications. The estimator-variable approach involves estimating the reliability of an identification given all factors that may have affected memory in that case. The system-variable approach has had a tremendous impact on reducing mistaken identifications, but the estimator-variable approach has not. This chapter explains why, despite their import, estimator variables have failed to distinguish reliable from unreliable identifications in real cases, and then introduces a new class of variables that fill the void—reflector variables. Reflectors reveal how strongly the suspect matches the witness’s memory for the culprit. Because guilty suspects tend to provide a stronger match-to-memory than do innocent suspects, reflector variables reflect whether the suspect in a lineup is guilty. This chapter argues that the reflector-variable approach requires videorecording lineups in their entirety.

The role of metals in forming the primary cross-links in slug glue was investigated. Several metal-binding proteins were identified in the defensive glue produced by the slug Arion subfuscus . Notably, the C-lectins that are unique to the glue are iron-binding proteins. This is unusual for C-lectins. Dissociating these proteins from iron does not affect the glue's stiffness. Similarly, several proteins that can bind to zinc were identified, but dissociating the proteins from zinc did not weaken the glue. These results suggest that metal coordination is not involved in the primary cross-links of this hydrogel glue. The stable cross-links that provide stiffness are more likely to be created by a catalytic event involving protein oxidation. Cross-linking was unexpectedly difficult to prevent. Collecting the glue into a large volume of ice-cold buffer with reagents aimed at inhibiting oxidative cross-linking caused a slight loss of cross-linking, as demonstrated by the appearance of uncross-linked proteins in native gel electrophoresis. Notable among these was a protein that is normally heavily oxidized (asmp165). Nevertheless, this effect was not large, suggesting that the primary cross-links form before secretion.

Background Endoscopic ultrasound guided gastrojejunostomy (EUS-GJ) with lumen apposing metal stents has recently emerged as a viable option, as an alternative to surgical gastrojejunostomy and endoscopic enteral stenting, for managing gastric outlet obstruction (GOO). We aim to perform a retrospective analysis of the efficacy, safety and outcomes of EUS-GJ performed at three tertiary institutions in the United Kingdom. Methods Consecutive patients who underwent EUS-GJ between August 2018 and March 2021 were identified from a prospectively maintained database. Data were obtained from interrogation of electronic health records. Results Twenty five patients (15 males) with a median age of 63 years old (range 29–80) were included for analysis. 88% (22/25) of patients had GOO due to underlying malignant disease. All patients were deemed surgically inoperable or at high surgical risk. Both technical and clinical success were achieved in 92% (23/25) of patients. There was an improvement in the mean Gastric Outlet Obstruction Scoring System scores following a technically successful EUS-GJ (2.52 vs 0.68, p Conclusion EUS-GJ in carefully selected patients is an effective and safe procedure when performed by experienced endoscopists.

Antibody conjugates of quantum dots (QDs) are expected to transform immunofluorescence staining by expanding multiplexed analysis and improving target quantification. Recently, a new generation of small QDs coated with multidentate polymers has improved QD labeling density in diverse biospecimens, but new challenges prevent their routine use. In particular, these QDs exhibit nonspecific binding to fixed cell nuclei and their antibody conjugates have random attachment orientations. This report describes four high-efficiency chemical approaches to conjugate antibodies to compact QDs. Methods include click chemistry and self-assembly through polyhistidine coordination, both with and without adaptor proteins that directionally orient antibodies. Specific and nonspecific labeling are independently analyzed after application of diverse blocking agent classes, and a new assay is developed to quantitatively measure intracellular labeling density based on microtubule stain connectivity. Results show that protein conjugation to the QD surface is required to simultaneously eliminate nonspecific binding and maintain antigen specificity. Of the four conjugation schemes, polyhistidine-based coordination of adaptor proteins with antibody self-assembly yields the highest intracellular staining density and the simplest conjugation procedure. Therefore, antibody and adaptor protein orientation, in addition to blocking optimization, are important determinants of labeling outcomes, insights that can inform translational development of these more compact nanomaterials.

Background: The COVID-19 pandemic presents one of the greatest threats to pediatric pain care seen in generations. Due to public health restrictions, many pediatric pain clinics halted in-person appointments, delaying and disrupting access to care. There is no existing research on the impacts of COVID-19 on pediatric chronic pain care in Canada or the challenges experienced by health care professionals and pain clinics. Aims: The aim of this study was to evaluate the impact of COVID-19 on Canadian pediatric chronic pain care by documenting how health care professionals provided care during the first six months of the pandemic. Methods: Two Canadian online cross-sectional surveys were conducted: one among Canadian pediatric pain clinic directors (Study 1) and another among multidisciplinary pediatric pain health care professionals (Study 2). Results: Responses from 13/13 Canadian pediatric pain clinics/rehabilitation programs indicated that all clinics provided virtual care during the pandemic. No significant changes were reported on the frequency of appointment requests. Most clinics reported no perceived change in patient pain levels (n = 9/13, 69%) or occurrence of pain flares (n = 10/13, 77%). Results from 151 individual health care professionals indicated that the majority (90%) of non–emergency department respondents were providing virtual care. The main challenges of virtual care included technological barriers, financial concerns, infrastructure and logistics, privacy, and clinical challenges. Conclusions: This study documented the impact of the COVID-19 pandemic on pediatric chronic pain care in Canada and highlighted the rapid shift to using virtual solutions. Simultaneously, respondents outlined current challenges and potential solutions to consider in the development of virtual care guidelines and policy in Canada.

Objective: Past research with one-person showup identification procedures suggests that providing witnesses with an explicit option to opt-out reduces innocent-suspect identifications without reducing culprit identifications (Weber & Perfect, 2012). This finding suggests that improving performance from identification procedures might be as simple as providing witnesses with the option to opt-out from deciding. We examined whether providing witnesses with an option to say "not sure" improved performance from showup procedures. Hypotheses: We predicted that participants would opt-out more when given a poor view. We also predicted that classification performance would be better for those who had option to opt-out, and this improvement would be more pronounced for those who had a poor view. Finally, we predicted that the opt-out option would reduce more low-confidence than high-confidence decisions. Method: We randomly assigned Amazon Mechanical Turk Workers (Experiment 1A: N = 2,003, average age = 36.90 [SD = 11.67], 57.86% female) and university students (Experiment 1B: N = 721, average age = 19.91 (SD = 3.99), 69.72% female) to a 2 (culprit: present, absent) × 2 (memory strength: strong, weak) × 2 (not sure option: yes, no) between-participants design. We manipulated memory strength by giving witnesses either a clear or degraded view of the encoding video. After watching the encoding video, participants completed a 10-min filler task and were then presented with a showup procedure. Results: Participants who were given a poor view were more likely to opt-out than were participants who were given a clear view. Participants who were given the option to respond not sure reported higher confidence in their decisions. However, the not sure option did not improve classification performance. Conclusion: Contrary to our prediction, we found no evidence that an opt-out option improves performance from a showup procedure, which is consistent with past research examining opt-out options with lineup procedures. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

open access article Hydrogels are versatile materials that have emerged in the last few decades as promising candidates for a range of applications in the biomedical field, from tissue engineering and regenerative medicine to controlled drug delivery. In the drug delivery field, in particular, they have been the subject of significant interest for the spatially and temporally controlled delivery of anticancer drugs and therapeutics. Self-assembling peptide-based hydrogels, in particular, have recently come to the fore as potential candidate vehicles for the delivery of a range of drugs. In order to explore how drug–peptide interactions influence doxorubicin (Dox) release, five β-sheet-forming self-assembling peptides with different physicochemical properties were used for the purpose of this study, namely: FEFKFEFK (F8), FKFEFKFK (FK), FEFEFKFE (FE), FEFKFEFKK (F8K), and KFEFKFEFKK (KF8K) (F: phenylalanine; E: glutamic acid; K: lysine). First, Dox-loaded hydrogels were characterized to ensure that the incorporation of the drug did not significantly affect the hydrogel properties. Subsequently, Dox diffusion out of the hydrogels was investigated using UV absorbance. The amount of drug retained in F8/FE composite hydrogels was found to be directly proportional to the amount of charge carried by the peptide fibers. When cation−π interactions were used, the position and number of end-lysine were found to play a key role in the retention of Dox. In this case, the amount of Dox retained in F8/KF8K composite hydrogels was linked to the amount of end-lysine introduced, and an end-lysine/Dox interaction stoichiometry of 3/1 was obtained. For pure FE and KF8K hydrogels, the maximum amount of Dox retained was also found to be related to the overall concentration of the hydrogels and, therefore, to the overall fiber surface area available for interaction with the drug. For 14 mM hydrogel, ∼170–200 μM Dox could be retained after 24 h. This set of peptides also showed a broad range of susceptibilities to enzymatic degradation opening the prospect of being able to control also the rate of degradation of these hydrogels. Finally, the Dox released from the hydrogel was shown to be active and affect 3T3 mouse fibroblasts viability in vitro. Our study clearly shows the potential of this peptide design as a platform for the formulation of injectable or sprayable hydrogels for controlled drug delivery.

Quantum dots (QDs) are a class of semiconductor nanocrystal used broadly as fluorescent emitters for analytical studies in the life sciences. These nanomaterials are particularly valuable for single-particle imaging and tracking applications in cells and tissues. An ongoing technological goal is to reduce the hydrodynamic size of QDs to enhance access to sterically hindered biological targets. Multidentate polymer coatings are a focus of these efforts and have resulted in compact and stable QDs with hydrodynamic diameters near 10 nm. New developments are needed to reach smaller sizes to further enhance transport through pores in cells and tissues. Here, we describe how structural characteristics of linear multidentate copolymers determine hydrodynamic size, colloidal stability, and biomolecular interactions of coated QDs. We tune copolymer composition, degree of polymerization, and hydrophilic group length, and coat polymers on CdSe and (core)shell (HgCdSe)CdZnS QDs. We find that a broad range of polymer structures and compositions yield stable colloidal dispersions; however, hydrodynamic size minimization and nonspecific binding resistance can only be simultaneously achieved within a narrow range of properties, requiring short polymers, balanced compositions, and small nanocrystals. In quantitative single-molecule imaging assays in synapses of live neurons, size reduction progressively increases labeling specificity of neurotransmitter receptors. Our findings provide a design roadmap to next-generation QDs with sizes approaching fluorescent protein labels that are the standard of many live-cell biomolecular studies.

A 44-year-old gentleman with stage III (T4N1M0) unresectable pancreatic adenocarcinoma at the uncinate process underwent percutaneous image guided Irreversible Electroporation (IRE). At day-1 post IRE the patient developed severe abdominal pain and had computed tomography for assessment of his symptoms. Computed tomography showed severe duodenal wall thickening with local inflammatory changes and was reported as duodenal infarction based on imaging features. Following conservative management with better pain management, both the clinical symptoms and imaging features resolved uneventfully. This case has highlighted severe duodenal swelling seen in patients post IRE for locally advanced pancreatic cancer may mimic duodenal infarction and is an important differential diagnosis to ensure appropriate clinical management.

A disintegrin and metalloprotease like decysin (ADAMDEC1) is a highly conserved secreted metalloprotease that belongs to a family of A disintegrin and metalloprotease (ADAMs). It is expressed exclusively in the gastrointestinal tract of animals and is known to possess a very rare zinc-binding motif (HEXXHXXGXXD) within the metalloprotease domain. The biological function of ADAMDEC1 as well as its true biological substrates remains unknown although its characteristic features reported to date suggest it plays a fundamental role in the physiology of mammals. Historically its expression, in healthy state, was believed to be limited to the monocyte-derived macrophages (MDMs) and dendritic cells within the gastrointestinal tract; however, the recent development of single-cell sequencing has provided evidence supporting its expression in a wider range of cell types. There is an increasing body of evidence linking the alterations in ADAMDEC1 expression and various inflammatory diseases and cancers. Although a detailed mechanistic role of ADAMDEC1 in these conditions remains elusive. In this review, we aim to summarise the characteristic features of this unique metalloprotease, discuss the associations with various human diseases and define the potential mechanistic role of ADAMDEC1 in mammalian physiology.

Hydrogels' hydrated fibrillar nature makes them the material of choice for the design and engineering of 3D scaffolds for cell culture, tissue engineering, and drug-delivery applications. One particular class of hydrogels which has been the focus of significant research is self-assembling peptide hydrogels. In the present work, we were interested in exploring how fiber-fiber edge interactions affect the self-assembly and gelation properties of amphipathic peptides. For this purpose, we investigated two β-sheet-forming peptides, FEFKFEFK (F8) and KFEFKFEFKK (KF8K), the latter one having the fiber edges covered by lysine residues. Our results showed that the addition of the two lysine residues did not affect the ability of the peptides to form β-sheet-rich fibers, provided that the overall charge carried by the two peptides was kept constant. However, it did significantly reduce edge-driven hydrophobic fiber-fiber associative interactions, resulting in reduced tendency for KF8K fibers to associate/aggregate laterally and form large fiber bundles and consequently network cross-links. This effect resulted in the formation of hydrogels with lower moduli but faster dynamics. As a result, KF8K fibers could be aligned only under high shear and at high concentration while F8 hydrogel fibers were found to align readily at low shear and low concentration. In addition, F8 hydrogels were found to fragment at high concentration because of the high aggregation state stabilizing the fiber bundles, resulting in fiber breakage rather than disentanglement and alignment.

When presenting a suspect to a witness for an identification attempt, fair lineups are superior to one-person showups. Relative to showups, fair lineups decrease innocent-suspect identifications to a greater extent than culprit identifications ( Steblay et al., 2003 ). We examined whether the lineup advantage extends from facial identification to forensic-object identification. Participants (N = 1906) watched a short video of a car theft and then completed two culprit-present or culprit-absent showups or lineups. Participants first attempted to identify the culprit from the video and then attempted to identify the vehicle from the video. Forensic-object lineups were superior to forensic-object showups to the extent that the cost of an innocent-suspect identification exceeded the cost of a missed culprit identification or to the extent that the base rate of culprit presence was low. Importantly, we are referring to actual costs and base rates in the real world rather than to methods of manipulating witness decision criteria (see Clark, 2012 for a similar approach). Finally, confidence discriminated between accurate and inaccurate suspect identifications for forensic-object lineups, but not for forensic-object showups.

Microfluidic techniques are widely used for high-throughput quantification and discrete analysis of micron-scale objects but are difficult to apply to molecular-scale targets. Instead, single-molecule methods primarily rely on low-throughput microscopic imaging of immobilized molecules. Here we report that commercial-grade flow cytometers can detect single nucleic acid targets following enzymatic extension and dense labeling with multiple distinct fluorophores. We focus on microRNAs, short nucleic acids that can be extended by rolling circle amplification (RCA). We labeled RCA-extended microRNAs with multicolor fluorophores to generate repetitive nucleic acid products with submicron sizes and tunable multispectral profiles. By cross-correlating the multiparametric optical features, signal-to-background ratios were amplified 1600-fold to allow single-molecule detection across 4 orders of magnitude of concentration. The limit of detection was measured to be 47 fM, which is 100-fold better than gold-standard methods based on polymerase chain reaction. Furthermore, multiparametric analysis allowed discrimination of different microRNA sequences in the same solution using distinguishable optical barcodes. Barcodes can apply both ratiometric and colorimetric signatures, which could facilitate high-dimensional multiplexing. Because of the wide availability of flow cytometers, we anticipate that this technology can provide immediate access to high-throughput multiparametric single-molecule measurements and can further be adapted to the diverse range of molecular amplification methods that are continually emerging.

Materials with short-wave infrared (SWIR) emission are promising contrast agents for in vivo animal imaging, providing high-contrast and high-resolution images of blood vessels in deep tissues. However, SWIR emitters have not been developed as molecular labels for microscopy applications in the life sciences, which require optimized probes that are bright, stable, and small. Here, we design and synthesize semiconductor quantum dots (QDs) with SWIR emission based on Hg(x)Cd(1−x)Se alloy cores red shifted to the SWIR by epitaxial deposition of thin Hg(x)Cd(1−x)S shells with a small band gap. By tuning alloy composition alone, the emission can be shifted across the visible-to-SWIR (VIR) spectra while maintaining a small and equal size, allowing direct comparisons of molecular labeling performance across a broad range of wavelength. After coating with click-functional multidentate polymers, the VIR-QD spectral series has high quantum yield in the SWIR (14–33%), compact size (13 nm hydrodynamic diameter), and long-term stability in aqueous media during continuous excitation. We show that these properties enable diverse applications of SWIR molecular probes for fluorescence microscopy using conjugates of antibodies, growth factors, and nucleic acids. A broadly useful outcome is a 10–55-fold enhancement of the signal-to-background ratio at both the single-molecule level and the ensemble level in the SWIR relative to visible wavelengths, primarily due to drastically reduced autofluorescence. We anticipate that VIR-QDs with SWIR emission will enable ultrasensitive molecular imaging of low-copy number analytes in biospecimens with high autofluorescence.