This volume is dedicated to the Southern Ocean Iron RElease Experiment (SOIREE), the first in situ iron fertilisation experiment performed in the polar waters of the Southern Ocean. SOIREE was an ...interdisciplinary study involving participants from six countries, and took place in February 1999 south of the Polar Front in the Australasian-Pacific sector of the Southern Ocean. Approximately 3800
kg of acidified FeSO
4.7H
2O and 165
g of the tracer sulphur hexafluoride (SF
6) were added to a 65-m deep surface mixed layer over an area of ∼50
km
2. Initially, mean dissolved iron concentrations were ∼2.7
nM, but decreased to ambient levels within days, requiring subsequent additions of 1550–1750
kg of acidified FeSO
4.7H
2O on days 3, 5 and 7 of the experiment. During the 13-day site occupation there were iron-mediated increases in phytoplankton growth rates, with marked increases in chlorophyll
a (up to 2
μg
l
−1) and production rates (up to 1.3
g
C
m
−2
d
−1). These resulted in subsequent changes in the pelagic ecosystem structure, and in the cycling of carbon, silica and sulphur, such as a 10% drawdown of surface CO
2. The SOIREE bloom persisted for >40 days following our departure from the site, as observed via SeaWiFS remotely sensed observations of Ocean Colour. Papers in this volume report in detail on aspects of this study, from the oceanographic setting of the experiment to a modelling simulation of the SOIREE bloom. A CD-ROM accompanies this volume and contains the main SOIREE datasets and ancillary information including the pre-experiment ‘desktop’ database study for site-selection, and satellite images of the SOIREE bloom.
PulseNet is a network that utilizes standardized pulsed-field gel electrophoresis (PFGE) protocols with the purpose of conducting laboratory-based surveillance of foodborne pathogens. PulseNet ...standardized PFGE protocols are subject to rigorous testing during the developmental phase and careful evaluation during a validation process assessing its robustness and reproducibility in different laboratories. Here we describe the development and validation of a rapid PFGE protocol for subtyping Vibrio cholerae for use in PulseNet International activities. While the protocol was derived from the existing PulseNet protocol for Escherichia coli O157, various aspects of this protocol were optimized for use with V. cholerae, most notably a change of the primary and secondary restriction enzyme to SfiI and NotI, respectively, and the use of a two-block electrophoresis program. External validation of this protocol was undertaken through a collaboration between three PulseNet Asia Pacific laboratories (Public Health Laboratory Centre, Hong Kong, National Institute of Infectious Diseases, Japan, and International Center for Diarrhoeal Diseases Research-Bangladesh) and PulseNet USA. Comparison of PFGE patterns generated by each of the participating laboratories demonstrated that the protocol is robust and reproducible.
Using a specially designed high- and constant-pressure combustion chamber, the propagation and morphologyof spark-ignited expanding spherical methane flames were imaged using schlieren cinematography ...and a high-speed digital camera. Stretch-free laminar burning velocities were subsequently determined for methane/air flames up to 20 atm and methane/oxygen/helium flames up to 60 atm. Computational simulation using GRI-MECH 3.0 showed satisfactory agreement with the experimental data up to 20 atm, and moderate deviation for pressure above 40 atm. Markstein lengths, global activation energies, and overall reaction orders were also determined as functions of pressure, with the latter two parameters exhibiting non-monotonic behavior caused by the changeover from H−O
2 to HO
2 chemistry similar to that of the explosion limits of homogeneous hydrogen/oxygen mixtures.
Resumen Introducción Se ha validado el uso de los anticuerpos anti-CdtB/anti-vinculina como biomarcadores para discriminar el SII-D de la EII, más no hay experiencia con ellos en Latinoamérica. ...Materiales y métodos Se analizaron pacientes que consultaron a una clínica de TGIF/motilidad en los últimos 7 meses por diarrea con dolor/distensión abdominal, y a quienes se les solicitó estos anticuerpos. Los pacientes fueron diagnosticados mediante los criterios de Roma III o con trastornos orgánicos. Se clasificaron a los pacientes con SII en SII-post infeccioso (PI) o SII-no PI. Resultados Treinta pacientes fueron estudiados. Se encontraron biomarcadores positivos en sujetos con SII-D y SII-D con sobreposición (58.8%) y SII-M (33.3%), sin diferencias entre aquellos con SII-PI (71.4%) vs. SII-no PI (41.7%) (p = 0.21). No hubo positividad en pacientes con otros TGIF o diarrea orgánica, excepto en uno con sobrecrecimiento bacteriano en el intestino delgado (SBID). Conclusión Nuestros datos apoyan el uso de esta prueba como una herramienta de diagnóstico de primera línea para confirmar la presencia de SII-D/SII-M según los criterios de Roma III.
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) induces T cell, B cell, and Ab responses that are detected for several months in recovered individuals. Whether this response resembles a ...typical respiratory viral infection is a matter of debate. In this study, we followed T cell and Ab responses in 24 mainly nonhospitalized human subjects who had recovered from PCR-confirmed SARS-CoV-2 infection at two time points (median of 45 and 145 d after symptom onset). Ab responses were detected in 95% of subjects, with a strong correlation between plasma and salivary anti-spike (anti-S) and anti-receptor binding domain IgG, as well as a correlation between circulating T follicular helper cells and the SARS-CoV-2-specific IgG response. T cell responses to SARS-CoV-2 peptides were determined using intracellular cytokine staining, activation markers, proliferation, and cytokine secretion. All study subjects had a T cell response to at least one SARS-CoV-2 Ag based on at least one T cell assay. CD4
responses were largely of the Th1 phenotype, but with a lower ratio of IFN-γ- to IL-2-producing cells and a lower frequency of CD8
:CD4
T cells than in influenza A virus (IAV)-specific memory responses within the same subjects. Analysis of secreted molecules also revealed a lower ratio of IFN-γ to IL-2 and an altered cytotoxic profile for SARS-CoV-2 S- and nucleocapsid-specific responses compared with IAV-specific responses. These data suggest that the memory T cell phenotype after a single infection with SARS-CoV-2 persists over time, with an altered cytokine and cytotoxicity profile compared with long-term memory to whole IAV within the same subjects.
Adult tissue repair and regeneration require stem-progenitor cells that can self-renew and generate differentiated progeny. Skeletal muscle regenerative capacity relies on muscle satellite cells ...(MuSCs) and their interplay with different cell types within the niche. However, our understanding of skeletal muscle tissue cellular composition is limited. Here, using a combined approach of single-cell RNA sequencing and mass cytometry, we precisely mapped 10 different mononuclear cell types in adult mouse muscle. We also characterized gene signatures and determined key discriminating markers of each cell type. We identified two previously understudied cell populations in the interstitial compartment. One expresses the transcription factor scleraxis and generated tenocytes in vitro. The second expresses markers of smooth muscle and mesenchymal cells (SMMCs) and, while distinct from MuSCs, exhibited myogenic potential and promoted MuSC engraftment following transplantation. The blueprint presented here yields crucial insights into muscle-resident cell-type identities and can be exploited to study muscle diseases.
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•Combination of single-cell RNA sequencing and mass cytometry•Construction of a cell atlas of adult skeletal muscle•Skeletal muscle is composed of 10 mononucleated cell types and myofibers•Skeletal muscle contains interstitial tenocytes and smooth muscle-mesenchymal cells
A strong characterization of cell types present in adult skeletal muscle is needed. Giordani et al. use both single-cell transcriptomics and mass cytometry to build a single-cell survey of adult skeletal muscle tissue and reveal understudied cell populations.
Background
The associations of screen use with children's cognition are not well evidenced and recent, large, longitudinal studies are needed. We aimed to assess the associations between screen use ...and cognitive development in the French nationwide birth cohort.
Methods
Time and context of screen use were reported by parents at ages 2, 3.5 and 5.5. Vocabulary, non‐verbal reasoning and general cognitive development were assessed with the MacArthur‐Bates Communicative Development Inventory (MB) at age 2, the Picture Similarities subtest from the British Ability Scales (PS) at age 3.5 and the Child Development Inventory (CDI) at ages 3.5 and 5.5. Outcome variables were age‐adjusted and standardized (mean = 100, SD = 15). Multiple imputations were performed among children (N = 13,763) with ≥1 screen use information and ≥1 cognitive measures. Cross‐sectional and longitudinal associations between screen use and cognitive development were assessed by linear regression models adjusted for sociodemographic and birth factors related to the family and children, and children's lifestyle factors competing with screen use. Baseline cognitive scores were further considered in longitudinal analysis.
Results
TV‐on during family meals at age 2, not screen time, was associated with lower MB scores at age 2 (β 95% CI = −1.67 −2.21, −1.13) and CDI scores at age 3.5 (−0.82 −1.31, −0.33). In cross‐sectional analysis, screen time was negatively associated with CDI scores at ages 3.5 (−0.67 −0.94, −0.40) and 5.5 (−0.47 −0.77, −0.16), and, in contrast, was positively associated with PS scores (0.39 0.07, 0.71) at age 3.5. Screen time at age 3.5 years was not associated with CDI scores at age 5.5 years.
Conclusions
Our study found weak associations of screen use with cognition after controlling for sociodemographic and children's birth factors and lifestyle confounders, and suggests that the context of screen use matters, not solely screen time, in children's cognitive development.
Abstract
The directed differentiation of human pluripotent stem cells (hPSCs) into defined populations has advanced regenerative medicine, especially for Parkinson's disease where clinical trials are ...underway. Despite this, tumorigenic risks associated with incompletely patterned and/or quiescent proliferative cells within grafts remain. Addressing this, donor stem cells carrying the suicide gene, thymidine kinase (activated by the prodrug ganciclovir, GCV), are employed to enable the programmed ablation of proliferative cells within neural grafts. However, coinciding the short half‐life of GCV with the short S‐phase of neural progenitors is a key challenge. To overcome this, a smart hydrogel delivery matrix is fabricatedto prolong GCV presentation. Following matrix embedment, GCV retains its functionality, demonstrated by ablation of hPSCs and proliferating neural progenitors in vitro. A prolonged GCV release is measured by mass spectrometry following the injection of a GCV‐functionalized hydrogel into mouse brains. Compared to suboptimal, daily systemic GCV injections, the intracerebral delivery of the functionalized hydrogel, as a “one‐off treatment”, reduce proliferative cells in both hPSC‐derived teratomas and neural grafts, without affecting the graft's functional unit (i.e., neurons). It is demonstrated that a functionalized biomaterial can enhance prodrug delivery and address safety concerns associated with the use of hPSCs for brain repair.
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