Association of radio polar cap brightening with bright patches and coronal holes

Radio-bright regions near the solar poles are frequently observed in Nobeyama Radioheliograph (NoRH) maps at 17 GHz, and often in association with coronal holes. However, the origin of these polar brightening has not been established yet. We propose that small magnetic loops are the source of these bright patches, and present modeling results that reproduce the main observational characteristics of the polar brightening within coronal holes at 17 GHz. The simulations were carried out by calculating the radio emission of the small loops, with several temperature and density profiles, within a 2D coronal hole atmospheric model. If located at high latitudes, the size of the simulated bright patches are much smaller than the beam size and they present the instrument beam size when observed. The larger bright patches can be generated by a great number of small magnetic loops unresolved by the NoRH beam. Loop models that reproduce bright patches contain denser and hotter plasma near the upper chromosphere and lower corona. On the other hand, loops with increased plasma density and temperature only in the corona do not contribute to the emission at 17 GHz. This could explain the absence of a one-to-one association between the 17 GHz bright patches and those observed in extreme ultraviolet. Moreover, the emission arising from small magnetic loops located close to the limb may merge with the usual limb brightening profile, increasing its brightness temperature and width.Comment: 8 pages, 6 figures, 1 table. Accepted for publication in The Astrophysical Journa

Modular Nucleic Acid Assembled p/MHC Microarrays for Multiplexed Sorting of Antigen-Specific T Cells

The human immune system consists of a large number of T cells capable of recognizing and responding to antigens derived from various sources. The development of peptide-major histocompatibility (p/MHC) tetrameric complexes has enabled the direct detection of these antigen-specific T cells. With the goal of increasing throughput and multiplexing of T cell detection, protein microarrays spotted with defined p/MHC complexes have been reported, but studies have been limited due to the inherent instability and reproducibility of arrays produced via conventional spotted methods. Herein, we report on a platform for the detection of antigen-specific T cells on glass substrates that offers significant advantages over existing surface-bound schemes. In this approach, called “Nucleic Acid Cell Sorting (NACS)”, single-stranded DNA oligomers conjugated site-specifically to p/MHC tetramers are employed to immobilize p/MHC tetramers via hybridization to a complementary-printed substrate. Fully assembled p/MHC arrays are used to detect and enumerate T cells captured from cellular suspensions, including primary human T cells collected from cancer patients. NACS arrays outperform conventional spotted arrays assessed in key criteria such as repeatability and homogeneity. The versatility of employing DNA sequences for cell sorting is exploited to enable the programmed, selective release of target populations of immobilized T cells with restriction endonucleases for downstream analysis. Because of the performance, facile and modular assembly of p/MHC tetramer arrays, NACS holds promise as a versatile platform for multiplexed T cell detection

DNA-Encoded Antibody Libraries: A Unified Platform for Multiplexed Cell Sorting and Detection of Genes and Proteins

Whether for pathological examination or for fundamental biology studies, different classes of biomaterials and biomolecules are each measured from a different region of a typically heterogeneous tissue sample, thus introducing unavoidable sources of noise that are hard to quantitate. We describe the method of DNA-encoded antibody libraries (DEAL) for spatially multiplexed detection of ssDNAs and proteins as well as for cell sorting, all on the same diagnostic platform. DEAL is based upon the coupling of ssDNA oligomers onto antibodies which are then combined with the biological sample of interest. Spotted DNA arrays, which are found to inhibit biofouling, are utilized to spatially stratify the biomolecules or cells of interest. We demonstrate the DEAL technique for (1) the rapid detection of multiple proteins within a single microfluidic channel, and, with the additional step of electroless amplification of gold-nanoparticle labeled secondary antibodies, we establish a detection limit of 10 fM for the protein IL-2, 150 times more sensitive than the analogue ELISA; (2) the multiplexed, on-chip sorting of both immortalized cell lines and primary immune cells with an efficiency that exceeds surface-confined panning approaches; and (3) the co-detection of ssDNAs, proteins, and cell populations on the same platform

Estimating the Coronal Supra-Arcade Downflow Radio Emission: From Centimeter Through Submillimeter Wavelengths

Supra-arcade downflows (SADs) are infrequent, wiggly, and low-emission structures observed to descend through the solar corona, mostly in EUV and soft X-ray frequencies. Based on their physical characteristics, SADs have been interpreted as low-density bubbles and are related to magnetic reconnection processes during long-term erupting flares. In this work, we use numerical MHD simulations to compute flux density maps, which are convolved with telescope beams to synthesize images with the aim to assess the expected SAD emission in radio wavelengths. We assume that the emission is thermal bremsstrahlung from a fully ionized plasma and without any appreciable gyroresonance contribution since magnetic fields are of the order of 10 G. We find that SAD emission should be optically thin in the frequency range of [10–1,000] GHz, and the spatially integrated flux should be larger than 1 Jy. We conclude, therefore, that SADs consistently are less bright than the surrounding fan and that observing SADs in radio frequencies between [0.5–1,000] GHz is feasible with present instrumentation. The observing strategies are proposed, including the instruments that can be used. Moreover, since the emission is, for the most part, optically thin, the flux density is proportional to temperature, density, and line-of-sight depth and when combined with EUV and soft X-ray images may allow a better density and temperature determination of SADs.Fil: Zurbriggen, Ernesto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentina. Universidade Presbiteriana Mackenzie; BrasilFil: Giménez de Castro, C. Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Costa, Andrea. Universidade Presbiteriana Mackenzie; Brasil. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; ArgentinaFil: Cécere, Mariana Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; Argentina. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; ArgentinaFil: Selhorst, Caius L.. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

The Submillimeter Active Region Excess Brightness Temperature during Solar Cycles 23 and 24

We report the temporal evolution of the excess brightness temperature above solar active regions (ARs) observed with the Solar Submillimeter Telescope (SST) at 212 ({\lambda} = 1.4 mm) and 405 GHz ({\lambda} = 0.7 mm) during Cycles 23 and 24. Comparison with the sunspot number (SSN) yields a Pearson's correlation coefficient R = 0.88 and 0.74 for 212 and 405 GHz, respectively. Moreover, when only Cycle 24 is taken into account the correlation coefficients go to 0.93 and 0.81 for each frequency. We derive the spectral index {\alpha} between SST frequencies and found a slight anti-correlation with the SSN (R = -0.25); however, since the amplitude of the variation is lower than the standard deviation we cannot draw a definite conclusion. Indeed, {\alpha} remains almost constant within the uncertainties with a median value approximate to 0 characteristic of an optically thick thermal source. Since the origin of the AR submillimeter radiation is thermal continuum produced at chromospheric heights, the strong correlation between the excess brightness temperature and the magnetic cycle evolution could be related to the available free magnetic energy to be released in reconnection events.Comment: Accepted for publication in the Astrophysical Journa

A comparative study of Tam3 and Ac transposition in transgenic tobacco and petunia plants

Transposition of the Anthirrinum majus Tam3 element and the Zea mays Ac element has been monitored in petunia and tobacco plants. Plant vectors were constructed with the transposable elements cloned into the leader sequence of a marker gene. Agrobacterium tumefaciens-mediated leaf disc transformation was used to introduce the transposable element constructs into plant cells. In transgenic plants, excision of the transposable element restores gene expression and results in a clearly distinguishable phenotype. Based on restored expression of the hygromycin phosphotransferase II (HPTII) gene, we established that Tam3 excises in 30% of the transformed petunia plants and in 60% of the transformed tobacco plants. Ac excises from the HPTII gene with comparable frequencies (30%) in both plant species. When the β-glucuronidase (GUS) gene was used to detect transposition of Tam3, a significantly lower excision frequency (13%) was found in both plant species. It could be shown that deletion of parts of the transposable elements Tam3 and Ac, removing either one of the terminal inverted repeats (TIR) or part of the presumptive transposase coding region, abolished the excision from the marker genes. This demonstrates that excision of the transposable element Tam3 in heterologous plant species, as documented for the autonomous element Ac, also depends on both properties. Southern blot hybridization shows the expected excision pattern and the reintegration of Tam3 and Ac elements into the genome of tobacco plants.

A clinical microchip for evaluation of single immune cells reveals high functional heterogeneity in phenotypically similar T cells

Cellular immunity has an inherent high level of functional heterogeneity. Capturing the full spectrum of these functions requires analysis of large numbers of effector molecules from single cells. We report a microfluidic platform designed for highly multiplexed (more than ten proteins), reliable, sample-efficient (~1 × 10^4 cells) and quantitative measurements of secreted proteins from single cells. We validated the platform by assessment of multiple inflammatory cytokines from lipopolysaccharide (LPS)-stimulated human macrophages and comparison to standard immunotechnologies. We applied the platform toward the ex vivo quantification of T cell polyfunctional diversity via the simultaneous measurement of a dozen effector molecules secreted from tumor antigen–specific cytotoxic T lymphocytes (CTLs) that were actively responding to tumor and compared against a cohort of healthy donor controls. We observed profound, yet focused, functional heterogeneity in active tumor antigen–specific CTLs, with the major functional phenotypes quantitatively identified. The platform represents a new and informative tool for immune monitoring and clinical assessment

Human biodistribution and radiation dosimetry of novel PET probes targeting the deoxyribonucleoside salvage pathway

PurposeDeoxycytidine kinase (dCK) is a rate-limiting enzyme in deoxyribonucleoside salvage, a metabolic pathway involved in the production and maintenance of a balanced pool of deoxyribonucleoside triphosphates (dNTPs) for DNA synthesis. dCK phosphorylates and therefore activates nucleoside analogs such as cytarabine, gemcitabine, decitabine, cladribine, and clofarabine that are used routinely in cancer therapy. Imaging probes that target dCK might allow stratifying patients into likely responders and nonresponders with dCK-dependent prodrugs. Here we present the biodistribution and radiation dosimetry of three fluorinated dCK substrates, (18)F-FAC, L: -(18)F-FAC, and L: -(18)F-FMAC, developed for positron emission tomography (PET) imaging of dCK activity in vivo.MethodsPET studies were performed in nine healthy human volunteers, three for each probe. After a transmission scan, the radiopharmaceutical was injected intravenously and three sequential emission scans acquired from the base of the skull to mid-thigh. Regions of interest encompassing visible organs were drawn on the first PET scan and copied to the subsequent scans. Activity in target organs was determined and absorbed dose estimated with OLINDA/EXM. The standardized uptake value was calculated for various organs at different times.ResultsRenal excretion was common to all three probes. Bone marrow had higher uptake for L: -(18)F-FAC and L: -(18)F-FMAC than (18)F-FAC. Prominent liver uptake was seen in L: -(18)F-FMAC and L: -(18)F-FAC, whereas splenic activity was highest for (18)F-FAC. Muscle uptake was also highest for (18)F-FAC. The critical organ was the bladder wall for all three probes. The effective dose was 0.00524, 0.00755, and 0.00910 mSv/MBq for (18)F-FAC, L: -(18)F-FAC, and L: -(18)F-FMAC, respectively.ConclusionThe biodistribution of (18)F-FAC, L: -(18)F-FAC, and L: -(18)F-FMAC in humans reveals similarities and differences. Differences may be explained by different probe affinities for nucleoside transporters, dCK, and catabolic enzymes such as cytidine deaminase (CDA). Dosimetry demonstrates that all three probes can be used safely to image the deoxyribonucleoside salvage pathway in humans

PCSK9 inhibitors and ezetimibe for the reduction of cardiovascular events: a clinical practice guideline with risk-stratified recommendations.

CLINICAL QUESTION In adults with low density lipoprotein (LDL) cholesterol levels >1.8 mmol/L (>70 mg/dL) who are already taking the maximum dose of statins or are intolerant to statins, should another lipid-lowering drug be added, either a proprotein convertase subtilisin/kexin 9 (PCSK9) inhibitor or ezetimibe, to reduce the risk of major cardiovascular events? If so, which drug is preferred? Having decided to use one, should we add the other lipid-lowering drug? CURRENT PRACTICE Most guidelines emphasise LDL cholesterol targets in their recommendations for prescribing PCSK9 inhibitors and/or ezetimibe in adults at high risk of experiencing a major adverse cardiovascular event. However, to achieve these goals in very high risk patients with statins alone is almost impossible, so physicians are increasingly considering other lipid-lowering drugs solely for achieving LDL cholesterol treatment goals rather than for achieving important absolute cardiovascular risk reduction. Most guidelines do not systematically assess the cardiovascular benefits of adding PCSK9 inhibitors and/or ezetimibe for all risk groups across primary and secondary prevention, nor do they report, in accordance with explicit judgments of assumed patients' values and preferences, absolute benefits and harms and potential treatment burdens. RECOMMENDATIONS The guideline panel provided mostly weak recommendations, which means we rely on shared decision making when applying these recommendations. For adults already using statins, the panel suggests adding a second lipid-lowering drug in people at very high and high cardiovascular risk but recommends against adding it in people at low cardiovascular risk. For adults who are intolerant to statins, the panel recommends using a lipid-lowering drug in people at very high and high cardiovascular risk but against adding it in those at low cardiovascular risk. When choosing to add another lipid-lowering drug, the panel suggests ezetimibe in preference to PCSK9 inhibitors. The panel suggests further adding a PCSK9 inhibitor to ezetimibe for adults already taking statins at very high risk and those at very high and high risk who are intolerant to statins. HOW THIS GUIDELINE WAS CREATED An international panel including patients, clinicians, and methodologists produced these recommendations following standards for trustworthy guidelines and using the GRADE approach. The panel identified four risk groups of patients (low, moderate, high, and very high cardiovascular risk) and primarily applied an individual patient perspective in moving from evidence to recommendations, though societal issues were a secondary consideration. The panel considered the balance of benefits and harms and burdens of starting a PCSK9 inhibitor and/or ezetimibe, making assumptions of adults' average values and preferences. Interactive evidence summaries and decision aids accompany multi-layered recommendations, developed in an online authoring and publication platform (www.magicapp.org) that also allows re-use and adaptation. THE EVIDENCE A linked systematic review and network meta-analysis (14 trials including 83 660 participants) of benefits found that PCSK9 inhibitors or ezetimibe probably reduce myocardial infarctions and stroke in patients with very high and high cardiovascular risk, with no impact on mortality (moderate to high certainty evidence), but not in those with moderate and low cardiovascular risk. PCSK9 inhibitors may have similar effects to ezetimibe on reducing non-fatal myocardial infarction or stroke (low certainty evidence). These relative benefits were consistent, but their absolute magnitude varied based on cardiovascular risk in individual patients (for example, for 1000 people treated with PCSK9 inhibitors in addition to statins over five years, benefits ranged from 2 fewer strokes in the lowest risk to 21 fewer in the highest risk). Two systematic reviews on harms found no important adverse events for these drugs (moderate to high certainty evidence). PCSK9 inhibitors require injections that sometimes result in injection site reactions (best estimate 15 more per 1000 in a 5 year timeframe), representing a burden and harm that may matter to patients. The MATCH-IT decision support tool allows you to interact with the evidence and your patients across the alternative options: https://magicevidence.org/match-it/220504dist-lipid-lowering-drugs/. UNDERSTANDING THE RECOMMENDATIONS The stratification into four cardiovascular risk groups means that, to use the recommendations, physicians need to identify their patient's risk first. We therefore suggest, specific to various geographical regions, using some reliable risk calculators that estimate patients' cardiovascular risk based on a mix of known risk factors. The largely weak recommendations concerning the addition of ezetimibe or PCSK9 inhibitors reflect what the panel considered to be a close balance between small reductions in stroke and myocardial infarctions weighed against the burdens and limited harms.Because of the anticipated large variability of patients' values and preferences, well informed choices warrant shared decision making. Interactive evidence summaries and decision aids linked to the recommendations can facilitate such shared decisions. The strong recommendations against adding another drug in people at low cardiovascular risk reflect what the panel considered to be a burden without important benefits. The strong recommendation for adding either ezetimibe or PCSK9 inhibitors in people at high and very high cardiovascular risk reflect a clear benefit.The panel recognised the key uncertainty in the evidence concerning patient values and preferences, namely that what most people consider important reductions in cardiovascular risks, weighed against burdens and harms, remains unclear. Finally, availability and costs will influence decisions when healthcare systems, clinicians, or people consider adding ezetimibe or PCSK9 inhibitors