Direct Analysis of Aerosolized Chemical Warfare Simulants Captured on a Modified Glass-Based Substrate by “Paper-Spray” Ionization

Paper spray ionization mass spectrometry offers a rapid alternative platform requiring no sample preparation. Aerosolized chemical warfare agent (CWA) simulants trimethyl phosphate, dimethyl methylphosphonate, and diisopropyl methylphosphonate were captured by passing air through a glass fiber filter disk within a disposable paper spray cartridge. CWA simulants were aerosolized at varying concentrations using an in-house built aerosol chamber. A custom 3D-printed holder was designed and built to facilitate the aerosol capture onto the paper spray cartridges. The air flow through each of the collection devices was maintained equally to ensure the same volume of air sampled across methods. Each approach yielded linear calibration curves with R2 values between 0.98–0.99 for each compound and similar limits of detection in terms of disbursed aerosol concentration. While the glass fiber filter disk has a higher capture efficiency (≈40%), the paper spray method produces analogous results even with a lower capture efficiency (≈1%). Improvements were made to include glass fiber filters as the substrate within the paper spray cartridge consumable. Glass fiber filters were then treated with ammonium sulfate to decrease chemical interaction with the simulants. This allowed for improved direct aerosol capture efficiency (>40%). Ultimately, the limits of detection were reduced to levels comparable to current worker population limits of 1 × 10–6 mg/m3

Calcium Homeostasis and Cone Signaling Are Regulated by Interactions between Calcium Stores and Plasma Membrane Ion Channels

Calcium is a messenger ion that controls all aspects of cone photoreceptor function, including synaptic release. The dynamic range of the cone output extends beyond the activation threshold for voltage-operated calcium entry, suggesting another calcium influx mechanism operates in cones hyperpolarized by light. We have used optical imaging and whole-cell voltage clamp to measure the contribution of store-operated Ca2+ entry (SOCE) to Ca2+ homeostasis and its role in regulation of neurotransmission at cone synapses. Mn2+ quenching of Fura-2 revealed sustained divalent cation entry in hyperpolarized cones. Ca2+ influx into cone inner segments was potentiated by hyperpolarization, facilitated by depletion of intracellular Ca2+ stores, unaffected by pharmacological manipulation of voltage-operated or cyclic nucleotide-gated Ca2+ channels and suppressed by lanthanides, 2-APB, MRS 1845 and SKF 96365. However, cation influx through store-operated channels crossed the threshold for activation of voltage-operated Ca2+ entry in a subset of cones, indicating that the operating range of inner segment signals is set by interactions between store- and voltage-operated Ca2+ channels. Exposure to MRS 1845 resulted in ∼40% reduction of light-evoked postsynaptic currents in photopic horizontal cells without affecting the light responses or voltage-operated Ca2+ currents in simultaneously recorded cones. The spatial pattern of store-operated calcium entry in cones matched immunolocalization of the store-operated sensor STIM1. These findings show that store-operated channels regulate spatial and temporal properties of Ca2+ homeostasis in vertebrate cones and demonstrate their role in generation of sustained excitatory signals across the first retinal synapse

Multinational companies, backward linkages and labour demand elasticities

This paper investigates the link between nationality of ownership and wage elasticities of labour demand at the level of the plant. In particular, we examine whether labour demand in multinationals becomes less elastic with respect to the wage if the plant has backward linkages with the local economy. Our empirical evidence, based on a rich plant level dataset, shows that the extent of local linkages indeed reduces the wage elasticity of labour demand. This result is economically important and holds for a number of different specifications.Leverhulme Trust (Programme Grant No. F114/BF; Economic and Social Research Council (Grant No. RES-000-22-0468)

The influence of stride width on kinematic and kinetics in high school and professional baseball pitchers: A propensity-matched biomechanical evaluation

OBJECTIVES: To evaluate kinematic and kinetic parameters for high school (HS) and professional (PRO) pitchers differentiated by stride width. DESIGN: Descriptive laboratory study. METHODS: HS (n = 36) and PRO (n = 172) baseball pitchers pitched 8-12 fastballs using 3D-motion capture (480-Hz). Pitchers were 1:1 propensity-scored matched by age, height, weight, and ball velocity based on \u27narrow\u27 versus \u27wide\u27 stride widths and kinematics and kinetics were compared using independent t-tests. Independent associations between variables and stride width were determined utilizing linear regressions. RESULTS: At foot contact, HS wide (n = 18) had significantly less lead knee flexion (41 ± 9° vs. 49 ± 6°, p = 0.007, d = -1.0) and less pelvis rotation (66 ± 9° vs. 57 ± 14°, p = 0.003 d = 0.8) compared to HS narrow (n = 18). PRO wide (n = 86) at ball release had significantly less pelvis rotation (-10 ± 10° vs. -15 ± 14°, p = 0.008, d = 0.4) and increased shoulder horizontal adduction (4±8° vs. -1±9°, p=0.003, d=0.5) compared to PRO narrow (n = 86). For every 10 cm increase in stride width, pelvis rotation at ball release decreased by 2° (B:0.10, β:0.20, p \u3c 0.001) in HS and 1.3° (B:0.08, β:0.13, p = 0.002) in PRO. CONCLUSIONS: HS and PRO pitchers differentiated by stride width demonstrated no significant difference in throwing arm kinetics. For both groups, wider stride width was associated with decreased pelvis rotation, which may contribute to inefficient utilization of kinetic energy. Ultimately, coaches and players may better focus their efforts on refining other kinematics for enhanced performance outcomes and safe pitching mechanics