Evaluation of the performance of a lateral flow device for quantitative detection of anti-SARS-CoV-2 IgG.

INTRODUCTION: The AbC-19™ lateral flow immunoassay (LFIA) performance was evaluated on plasma samples from a SARS-CoV-2 vaccination cohort, WHO international standards for anti-SARS-CoV-2 IgG (human), individuals ≥2 weeks from infection of RT-PCR confirmed SARS-CoV-2 genetic variants, as well as microorganism serology. METHODS: Pre-vaccination to three weeks post-booster samples were collected from a cohort of 111 patients (including clinically extremely vulnerable patients) from Northern Ireland. All patients received Oxford-AstraZeneca COVID-19 vaccination for the first and second dose, and Pfizer-BioNTech for the third (first booster). WHO international standards, 15 samples from 2 variants of concern (Delta and Omicron) and cross-reactivity with plasma samples from other microorganism infections were also assessed on AbC-19™. RESULTS: All 80 (100%) participants sampled post-booster had high positive IgG responses, compared to 38/95 (40%) participants at 6 months post-first vaccination. WHO standard results correlated with information from corresponding biological data sheets, and antibodies to all genetic variants were detected by LFIA. No cross-reactivity was found with exception of one (of five) Dengue virus samples. CONCLUSION: These findings suggest BNT162b2 booster vaccination enhanced humoral immunity to SARS-CoV-2 from pre-booster levels, and that this antibody response was detectable by the LFIA. In combination with cross-reactivity, standards and genetic variant results would suggest LFIA may be a cost-effective measure to assess SARS-CoV-2 antibody status.

A programmable soft chemo-mechanical actuator exploiting a catalyzed photochemical water-oxidation reaction.

We describe a composite hydrogel containing an embedding coupled chemistry for light-sensitized catalytic reactions that enables chemo-mechanical actuation of poly(acrylic acid)-based gels. In these materials, a photosensitizer and catalyst-ruthenium trisbipyridine and iridium dioxide nanoparticles, respectively-are incorporated into the hydrogel where together, with visible light irradiation, they undergo a catalytic water-oxidation reaction that lowers the pH and induces a dissipative/chemically-driven strain change in the gel. To demonstrate the capacity for 3D chemo-mechanical actuation, a layer of non-pH responsive poly(2-hydroxyethyl methacrylate) is added to the photo-active composite gel to create a model bimorph actuator. Triggering and terminating the water-oxidation reaction leads to a programmatic expansion and contraction of the active layer, which induces different modes of biomimetic curling motions in the bimorph actuator in light and dark environments. The efficiency of this system is fundamentally limited by the system-level design, which provides no capacity to sustain a local pH gradient against diffusive mixing. Even so, if the initial pH of the background solution is reestablished either actively or passively between each reaction cycle, it is possible to realize multiple cycles of reversible actuation. We describe a thermodynamic analysis of this system which identifies specific features mediating efficiency losses and conceptual requirements for mesoscopic design rules for optimization of this system and for advancing soft actuation systems in general.

Modular Polymer Biosensors by Solvent Immersion Imprint Lithography.

We recently demonstrated Solvent Immersion Imprint Lithography (SIIL), a rapid benchtop microsystem prototyping technique, including polymer functionalization, imprinting and bonding. Here, we focus on the realization of planar polymer sensors using SIIL through simple solvent immersion without imprinting. We describe SIIL's impregnation characteristics, including an inherent mechanism that not only achieves practical doping concentrations, but their unexpected 2-fold enhancement compared to the immersion solution. Subsequently, we developed and characterized optical sensors for detecting molecular O2. To this end, a substantially high dynamic range is reported, including its control through the immersion duration, a manifestation of SIIL's modularity. Overall, SIIL exhibits the potential of improving the operating characteristics of polymer sensors, while significantly accelerating their prototyping, as it requires a few seconds of processing and no need for substrates or dedicated instrumentation. These are critical for O2 sensing as probed by way of example here, as well as any polymer permeable reactant.

Assessing reproductive isolation using a contact zone between parapatric lake-stream stickleback ecotypes.

Ecological speciation occurs when populations evolve reproductive isolation as a result of divergent natural selection. This isolation can be influenced by many potential reproductive barriers, including selection against hybrids, selection against migrants and assortative mating. How and when these barriers act and interact in nature is understood for relatively few empirical systems. We used a mark-recapture experiment in a contact zone between lake and stream three-spined sticklebacks (Gasterosteus aculeatus, Linnaeus) to evaluate the occurrence of hybrids (allowing inferences about mating isolation), the interannual survival of hybrids (allowing inferences about selection against hybrids) and the shift in lake-like vs. stream-like characteristics (allowing inferences about selection against migrants). Genetic and morphological data suggest the occurrence of hybrids and no selection against hybrids in general, a result contradictory to a number of other studies of sticklebacks. However, we did find selection against more lake-like individuals, suggesting a barrier to gene flow from the lake into the stream. Combined with previous work on this system, our results suggest that multiple (most weakly and often asymmetric) barriers must be combining to yield substantial restrictions on gene flow. This work provides evidence of a reproductive barrier in lake-stream sticklebacks and highlights the value of assessing multiple reproductive barriers in natural contexts.

Prevención de síntomas visuales y músculo-esqueléticos asociados al uso de ordenador en el trabajo / Workplace interventions to prevent musculoskeletal and visual symptoms and disorders among computer users: A systematic review

Antecedentes: La literatura científica sobre el efecto de las intervenciones en el puesto de trabajo, en la compensación de un defecto refractivo y en la conducta sobre los síntomas músculo-esqueléticos y visuales en los usuarios de ordenador, es amplia y heterogénea. Método: Se realizó una revisión sistemática de la literatura como la mejor síntesis de la evidencia para abordar la siguiente cuestión general: ¿Tienen las intervenciones en trabajadores de oficina que son usuarios de ordenador un efecto sobre la salud músculo-esquelética o visual? También se realizó una evaluación de intervenciones específicas. Resultados: La búsqueda inicial identificó 7.313 artículos que se redujeron a 31 estudios tras analizar contenido y calidad. En general, se observó un nivel mixto de evidencia para la pregunta general. Se observó una evidencia moderada de que: (1) la adaptación de los puestos de trabajo no tenía ningún efecto, (2) tampoco la realización de descansos y ejercicio y (3) utilizar dispositivos alternativos a los ratones convencionales sí tenía un efecto positivo. Para el resto de intervenciones se observó una evidencia del efecto mixta o insuficiente. Conclusión: Se encontraron pocos estudios de alta calidad que examinaran los efectos de las intervenciones en oficinas sobre los problemas musculo-esqueléticos y de la salud visual

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Passive transfer of antibodies to the linear epitope 60 kD Ro 273-289 induces features of Sjögren's syndrome in naive mice.

Sjögren's syndrome (SS) is an autoimmune inflammatory disease that primarily affects the lacrimal and salivary glands causing dry eyes and mouth. Antibodies to Ro60 are observed frequently in patients with SS; however, the role of these antibodies in SS initiation and progression remains unclear. The sequence Ro60 273-289 (Ro274) is a known B cell epitope of Ro60 and antibodies to this epitope have been observed in a subset of SS patients and in animals immunized with Ro60 protein. Animals immunized with Ro274 linear peptide develop a Sjögren's-like illness. We hypothesized that passive transfer of anti-Ro274-specific immunoglobulin (Ig)G would induce a Sjögren's-like phenotype. To evaluate this hypothesis, we adoptively transferred affinity-purified Ro274 antibodies into naive BALB/c animals, then evaluated salivary gland histology, function and IgG localization 4 days post-transfer. At this time-point, there was no demonstrable mononuclear cell infiltration and salivary glands were histologically normal, but we observed a functional deficit in stimulated salivary flow of animals receiving Ro274 antibodies compared to animals receiving control IgG. Cellular fractionation and enzyme-linked immunosorbent assay revealed Ro274-specific antibodies in the nucleus and cytoplasmic fractions of isolated parotid salivary gland cells that was confirmed by immunohistochemistry. These data support the hypothesis that antibodies to Ro274 deposit in salivary glands can enter intact salivary gland cells and are involved in the dysregulation of salivary flow in SS.

Restoration of large damage volumes in polymers.

The regenerative power of tissues and organs in biology has no analog in synthetic materials. Although self-healing of microscopic defects has been demonstrated, the regrowth of material lost through catastrophic damage requires a regenerative-like approach. We demonstrate a vascular synthetic system that restores mechanical performance in response to large-scale damage. Gap-filling scaffolds are created through a two-stage polymer chemistry that initially forms a shape-conforming dynamic gel but later polymerizes to a solid structural polymer with robust mechanical properties. Through the control of reaction kinetics and vascular delivery rate, we filled impacted regions that exceed 35 mm in diameter within 20 min and restored mechanical function within 3 hours. After restoration of impact damage, 62% of the total absorbed energy was recovered in comparison with that in initial impact tests.

Genetic analysis of sympatric migratory ecotypes of Arctic charr Salvelinus alpinus: alternative mating tactics or reproductively isolated strategies?

Three populations of Arctic charr Salvelinus alpinus from southern Baffin Island were previously identified to display variable migratory phenotypes, with an anadromous component of the population and another remaining resident in fresh water. In this study, 14 microsatellite markers were used to help distinguish between two alternative hypotheses to explain the co-existence of the two ecotypes: that the two ecotypes originate from a single population and are the result of a conditional mating tactic or that the migratory ecotypes are reproductively isolated populations utilizing alternative migratory strategies. In two of the three replicate systems, F(ST) values between the resident and anadromous individuals were non-significant, while they were significant in a third sampling location. Bayesian clustering analysis implemented in structure, however, failed to identify any within-location clustering in all three sampling locations. It is concluded from these analyses that the life-history ecotypes are most likely conditional mating tactics, rather than reproductively isolated populations. Other evidence in favour of the alternative mating tactic hypothesis is briefly reviewed, and implications for management of those populations are discussed.

Puny males punch above their weight to preserve genetic diversity in a declining Atlantic salmon population.

Many salmonid fish populations have anadromous (i.e. migratory) and nonanadromous individuals co-existing in sympatry. The nonanadromous individuals, frequently males, mature at a much smaller size in freshwater without undergoing marine migrations and often successfully fertilize many eggs laid by anadromous females. Because these small males do not recruit to fisheries, they are often not regarded in high esteem by fishers. In this issue of Molecular Ecology, Johnstone et al. (2013) demonstrate that by substantially contributing to reproduction, such males help maintain genetic diversity in a declining population of Atlantic salmon (Salmo salar). Their results show that estimates of effective population size (Ne), obtained by counting the number of anadromous adults returning from sea and correcting for unequal sex ratios, are lower than estimates generated from genetic markers. Many mechanisms are expected to reduce Ne below the adult census population size (N); the opposite pattern of Ne > N observed by Johnstone et al. (2013) is difficult to explain unless the reproductive effort of nonanadromous males is accounted for. The results have important implications for the conservation of small populations and highlight the challenges of relating Ne to N in organisms with complex life histories.

Immunization with 60 kD Ro peptide produces different stages of preclinical autoimmunity in a Sjögren's syndrome model among multiple strains of inbred mice.

Sjögren's syndrome is a chronic illness manifested characteristically by immune injury to the salivary and lacrimal glands, resulting in dry mouth/eyes. Anti-Ro [Sjögren's syndrome antigen A (SSA)] and anti-La [Sjögren's syndrome antigen B (SSB)] autoantibodies are found frequently in Sjögren's subjects as well as in individuals who will go on to develop the disease. Immunization of BALB/c mice with Ro60 peptides results in epitope spreading with anti-Ro and anti-La along with lymphocyte infiltration of salivary glands similar to human Sjögren's. In addition, these animals have poor salivary function/low saliva volume. In this study, we examined whether Ro-peptide immunization produces a Sjögren's-like illness in other strains of mice. BALB/c, DBA-2, PL/J, SJL/J and C57BL/6 mice were immunized with Ro60 peptide-274. Sera from these mice were studied by immunoblot and enzyme-linked immunosorbent assay for autoantibodies. Timed salivary flow was determined after pharmacological stimulation, and salivary glands were examined pathologically. We found that SJL/J mice had no immune response to the peptide from Ro60, while C57BL/6 mice produced antibodies that bound the peptide but had no epitope spreading. PL/J mice had epitope spreading to other structures of Ro60 as well as to La, but like C57BL/6 and SJL/J had no salivary gland lymphocytic infiltration and no decrement of salivary function. DBA-2 and BALB/c mice had infiltration but only BALB/c had decreased salivary function. The immunological processes leading to a Sjögren's-like illness after Ro-peptide immunization were interrupted in a stepwise fashion in these differing mice strains. These data suggest that this is a model of preclinical disease with genetic control for epitope spreading, lymphocytic infiltration and glandular dysfunction.

Infant health effects of a nurse-community health worker home visitation programme: a randomized controlled trial.

BACKGROUND: Home visiting is supported as a way to improve child health and development. Home visiting has been usually provided by nurses or community health workers (CHWs). Few studies compared the child health advantages of a nurse-CHW team approach over nurse prenatal and postnatal home visiting. METHODS: A randomized trial was conducted with Medicaid-insured pregnant women in Kent County, Michigan. Pregnant women were assigned to a team intervention including nurse-CHW home visitation, or standard community care (CC) including nurse home visitation. Morbidity was assessed in 530 infants over their first 12 months of life from medical claims and reported by the mother. RESULTS: There were no differences in overall child health between the nurse-CHW intervention and the CC arm over the first year of life. There were fewer mother-reported asthma/wheezing/croup diagnostics in the team intervention group among infants whose mothers have low psychosocial resources (13% vs. 27%, P = 0.01; adjusted OR = 0.4, P = 0.01). There were no differences in diagnosed asthma/wheezing/croup documented by medical claims. There were no differences in immunizations, hospitalizations and ear infections. CONCLUSIONS: There was no strong evidence that infant health was improved by the addition of CHWs to a programme of CC that included nurse home visitation. Targeting such interventions at common health problems of infancy and childhood or at diagnosed chronic conditions may prove more successful.

Hand problems in migrant farmworkers.

PURPOSE: We estimated the self-reported prevalence of hand problems and identified factors associated with them in this cross-sectional study including 390 farmworkers representing 180 migrant farmworker families from Starr County, Texas. METHODS: A two-year cohort study (1999-2001), "Injury and Illness Surveillance in Migrant Farmworkers (MANOS), "provided the data for this study. We calculated the prevalence for the two-year follow-up period, stratified by family member and survey year. The associated work and non-work factors were identified for the entire sample using multilevel mixed-effects logistic regression analysis. RESULTS: Prevalence for hand problems was 29.0% and 17.8% for the first and second study years, respectively. Significant factors (associated odds ratios) included increasing age (1.07), female gender (3.49), duration of sleep while migrating (0.68), participation group working in both study years 1 and 2 (0.21) or year 2 only (0.14), working on average more than 11 hours per day (8.23), moving heavy objects at work (3.97), working with hand-held vibrating tools/machinery (5.16), and working in meat processing (40.48). CONCLUSIONS: The prevalence of hand problems in migrant farmworkers reported by this study was notable for mothers, fathers, and children. Further research with refined ergonomic exposure and outcome assessments for investigating hand injuries in migrant farmworkers is indicated, specifically among youth. The role of sleep in preventing symptoms should also be explored.

3-D analysis of semiconductor dopant distributions in a patterned structure using LEAP.

This work presents the first 3-D analysis of lateral dopant diffusion in a patterned structure using a pulsed laser-assisted local electrode atom probe (LEAP). A structure similar to a device channel was created for this work by performing a 3 keV, 1 x 10(15) cm(-2) As+ implant on a poly-Si line patterned wafer with 70 nm line width and 200 nm line pitch. The wafer was subsequently annealed at 950 degrees C for 1s. LEAP samples were made using a site-selective in-situ focused ion beam (FIB) process. The results from LEAP analysis were then compared with high-resolution transmission electron microscopy (HRTEM) and Florida object-oriented process simulator (FLOOPS) results. Good structural agreement was found between the LEAP and HRTEM results. Several 1-D As concentration profiles extracted from the LEAP data were also found to be in good agreement with FLOOPS process simulation results. These profiles also represent for the first time that results from a 3-D process simulator have been able to be confirmed experimentally using a single sample.

Life extension of self-healing polymers with rapidly growing fatigue cracks.

Self-healing polymers, based on microencapsulated dicyclopentadiene and Grubbs' catalyst embedded in the polymer matrix, are capable of responding to propagating fatigue cracks by autonomic processes that lead to higher endurance limits and life extension, or even the complete arrest of the crack growth. The amount of fatigue-life extension depends on the relative magnitude of the mechanical kinetics of crack propagation and the chemical kinetics of healing. As the healing kinetics are accelerated, greater fatigue life extension is achieved. The use of wax-protected, recrystallized Grubbs' catalyst leads to a fourfold increase in the rate of polymerization of bulk dicyclopentadiene and extends the fatigue life of a polymer specimen over 30 times longer than a comparable non-healing specimen. The fatigue life of polymers under extremely fast fatigue crack growth can be extended through the incorporation of periodic rest periods, effectively training the self-healing polymeric material to achieve higher endurance limits.

PTTG's C-terminal PXXP motifs modulate critical cellular processes in vitro.

Human pituitary tumor-transforming gene (PTTG), known also as securin, is a multifunctional protein implicated in the control of mitosis and the pathogenesis of thyroid, colon, oesophageal and other tumour types. Critical to PTTG function is a C-terminal double PXXP motif, forming a putative SH3-interacting domain and housing the gene's sole reported phosphorylation site. The exact role of phosphorylation and PXXP structure in the modulation of PTTG action in vitro remains poorly understood. We therefore examined the mitotic, transformation, proliferation and transactivation function of the C-terminal PXXP motifs of human PTTG. Live-cell imaging studies using an EGFP-PTTG construct indicated that PTTG's regulation of mitosis is retained regardless of phosphorylation status. Colony-formation assays demonstrated that phosphorylation of PTTG may act as a potent inhibitor of cell transformation. In proliferation assays, NIH-3T3 cells stable transfected and overexpressing mutations preventing PTTG phosphorylation (Phos-) showed significantly increased [3H]thymidine incorporation compared with WT, whereas mutants mimicking constitutive phosphorylation of PTTG (Phos+) exhibited reduced cell proliferation. We demonstrated that PTTG transactivation of FGF-2 in primary thyroid and PTTG-null cell lines was not affected by PTTG phosphorylation but was prevented by a mutant disrupting the PXXP motifs (SH3-). Taken together, our data suggest that PXXP structure and phosphorylation are likely to exert independent and critical influences upon PTTG's diverse actions in vitro.

Disruption of the structure of the Golgi apparatus and the function of the secretory pathway by mutants G93A and G85R of Cu, Zn superoxide dismutase (SOD1) of familial amyotrophic lateral sclerosis.

The Golgi apparatus of motor neurons (GA) is fragmented in sporadic amyotrophic lateral sclerosis (ALS), in familial ALS with SOD1 mutations, and in mice that express SOD1G93A of familial ALS, in which it was detected months before paralysis. In paralyzed transgenic mice expressing SOD1G93A or SOD1G85R, mutant proteins aggregated not only in the cytoplasm of motor neurons, but also in astrocytes and oligodendrocytes. Furthermore, aggregation of the G85R protein damaged astrocytes and was associated with rapidly progressing disease. In order to gain insight into the functional state of the fragmented GA, we examined the effects of S0D1 mutants G93A and G85R in Chinese Hamster Ovary Cells (CHO). In contrast to cells expressing the wt and G93A, the G85R expressers had no SOD1 activity. However, cells expressing both mutants, and to a lesser degree the wt, showed decreased survival, fragmentation of the GA, and dysfunction of the secretory pathway, which was assessed by measuring the amount of cell surface co-expressed CD4, a glycoprotein processed through the GA. The G93A and wt proteins were partially recovered in detergent insoluble fractions; while the recovery of G85R was minimal. Both mutants showed equal reductions of cell survival and function of the secretory pathway, in comparison to the wt and cells expressing mutant alsin, a protein found in rare cases of fALS. These results are consistent with the conclusion that the two SOD1 mutants, by an unknown mechanism, promote the dispersion of the GA and the dysfunction of the secretory pathway. This and other in vitro models of mutant SOD1 toxicity may prove useful in the elucidation of pathogenetic mechanisms.

Multiparameter flow cytometric approach for simultaneous evaluation of T lymphocyte-endothelial cell interactions.

Since vascular endothelium is now recognized as an immunologically active tissue, a better understanding of the relationship between endothelial cells and T lymphocytes is critical to the field of solid organ transplantation. Investigations of endothelial cell-T cell interactions have been limited by methodology. We developed a flow cytometric method allowing for concurrent investigation of multiple cell populations within the same culture that can be applied to these complex interactions. Allogeneic CD8+ or CD4+ T cells labeled with 5,6-carboxyfluorescein diacetate succinimidyl ester (CFSE) were added to a murine endothelial cell monolayer, in which endothelial proliferation was not inhibited by irradiation or addition of a cell cycle-blocking agent. At specific time points, the coculture was analyzed by flow cytometry. T-cell proliferation could be detected by gating on the T-cell subset and evaluating the CFSE fluorescence peaks. By directly analyzing cellular division, we minimized erroneous interpretation of the data encountered by previous studies, which utilized (3)H-thymidine incorporation as sole measure of proliferation. Further subgating on cells that divided facilitated the study of CD8+ lymphocyte activation, differentiation, and acquisition of effector function. By gating on the endothelial cell population, phenotypic changes such as upregulation of surface MHC molecules or immune-mediated apoptosis could be detected. In conclusion, we present a flow cytometric approach that could have important applications for clinical immunological monitoring in allogeneic or xenogeneic transplantation, and might provide the requisite information to better tailor immunotherapy to prevent chronic rejection.