Femtosecond intersubband relaxation and population inversion in stepped quantum well

We have investigated intersubband relaxation rates in a stepped quantum well at room temperature using differential transmission spectroscopy with subpicosecond time resolution. The dynamics of the subband populations are derived from the experimentally observed reduction of oscillator strength of the corresponding exciton transitions. In the stepped quantum well the relaxation through longitudinal optical‐phonon emission from n=3 to 1 (25 ps) is slower than that from 2 to 1 (220 fs), due to the reduced wave function overlap and larger wave vector required for intersubband scattering. When the n=3 state is pumped, a population inversion between n3 and n2 (which are separated by 7 THz) is observed. © 1996 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70388/2/APPLAB-68-4-435-1.pd

Innovation in health economic modelling of service improvements for longer-term depression: demonstration in a local health community

Background The purpose of the analysis was to develop a health economic model to estimate the costs and health benefits of alternative National Health Service (NHS) service configurations for people with longer-term depression. Method Modelling methods were used to develop a conceptual and health economic model of the current configuration of services in Sheffield, England for people with longer-term depression. Data and assumptions were synthesised to estimate cost per Quality Adjusted Life Years (QALYs). Results Three service changes were developed and resulted in increased QALYs at increased cost. Versus current care, the incremental cost-effectiveness ratio (ICER) for a self-referral service was £11,378 per QALY. The ICER was £2,227 per QALY for the dropout reduction service and £223 per QALY for an increase in non-therapy services. These results were robust when compared to current cost-effectiveness thresholds and accounting for uncertainty. Conclusions Cost-effective service improvements for longer-term depression have been identified. Also identified were limitations of the current evidence for the long term impact of services

Probable maximum precipitation estimation in a humid climate

Probable maximum precipitation (PMP) estimation is one of the most important components for designing hydraulic structures. The aim of this study was the estimation of 24&thinsp;h PMP (PMP24) using statistical and hydro-meteorological (physical) approaches in the humid climate of the Qareh-Su basin, which is located in the northern part of Iran. Firstly, for the statistical estimate of PMP, the equations of empirical curves of the Hershfield method were extracted and the Hershfield standard and modified methods were written in Java programming language, as a user-friendly and multi-platform application called the PMP Calculator. Secondly, a hydro-meteorological approach, which is called the convergence model, was used to calculate PMP24. The results of both approaches were evaluated based on statistical criteria, such as the mean absolute error (MAE), mean squared error (MSE), root mean squared error (RMSE), mean absolute percentage error (MAPE), correlation coefficient (r), and coefficient of determination (R2). The maximum values of PMP24 for the Hershfield standard and modified methods were estimated to be 448 and 201&thinsp;mm, respectively, while the PMP obtained by the physical approach was 143&thinsp;mm. Comparison of PMP24 values with the maximum 24&thinsp;h precipitation demonstrated that based on performance criteria including the MAE, MSE, RMSE, MAPE, r, and R2, the physical approach performed better than the statistical approach and it provided the most reliable estimates for PMP. Also, the accuracy of the Hershfield modified method was better than the standard method using modified Km values, and the standard method gives excessively large PMP for construction costs.</p

Chitosan/polyvinyl alcohol nanofibrous membranes: towards green super-adsorbents for toxic gases

Removal of hazardous gases from the atmosphere has become a big challenge for scientists and engineers alike. Eco-friendly nature of biopolymers has given a new dimension to the debate within the environmental science area but attempts mainly failed to cleanse the air stream of toxic gases as a consequence of design imperfections. In this work, green electrospun nanofibrous membranes based on chitosan (Cs)/polyvinyl alcohol (PVA) composite with a very high carbon monoxide adsorption capacity (much higher than the values one may expect from activated carbon and zeolite adsorbents, and also higher than that of the metal-organic framework) are developed. 2 k�1 factorial design, response surface and desirability function analyses are merged to optimize the electrospinning parameters for functional-based carbon monoxide elimination. The best Cs/PVA adsorbent obtained through multi-objective optimization has a very high desirability value level of 0.953. Optimized electrospinning parameters are: Voltage = 17 kV, spinning distance = 13 cm, flow rate = 0.2 mL/h, and PVA concentration = 6 wt.; and optimized properties are: maximum thermal stability = 329 °C, minimum fiber diameter = 9.8 nm, and maximum surface area = 2204 m 2 /g. This work opens a new era for taking the next steps towards the design and optimization of green super-adsorbents for gaseous contaminations. © 201

Studying crystallisation processes using electron microscopy: The importance of sample preparation

We present a comparison of common electron microscopy sample preparation methods for studying crystallisation processes from solution using both scanning and transmission electron microscopy (SEM and TEM). We focus on two widely studied inorganic systems: calcium sulphate, gypsum (CaSO4·2H2O) and calcium carbonate (CaCO3). We find significant differences in crystallisation kinetics and polymorph selection between the different sample preparation methods, which indicate that drying and chemical quenching can induce severe artefacts that are capable of masking the true native state of the crystallising solution. Overall, these results highlight the importance of cryogenic (cryo)-quenching crystallising solutions and the use of full cryo-TEM as the most reliable method for studying the early stages of crystallisation

MicroRNA-221 and -222 modulate intestinal inflammatory Th17 cell response as negative feedback regulators downstream of interleukin-23

Mikami et al. examine the role of miR-221/222 in helper T cells in the gut. MiR-221/222 are induced by IL-23 and suppressed by TGFβ, targeting Maf and IL23r for degradation. During inflammation, these miRNAs serve as a negative feedback rheostat to constrain IL23-Th17 cell responses

Interleukin 22 orchestrates a pathological endoplasmic reticulum stress response transcriptional programme in colonic epithelial cells

Objective - The functional role of interleukin-22 (IL22) in chronic inflammation is controversial and mechanistic insights into how it regulates target tissue are lacking. In this study, we evaluated the functional role of IL22 in chronic colitis and probed mechanisms of IL22- mediated regulation of colonic epithelial cells. Design – To investigate the functional role of IL22 in chronic colitis and how it regulates colonic epithelial cells we employed a 3-dimentional mini-gut epithelial organoid system,in vivo disease models and transcriptomic datasets in human IBD. Results - As well as inducing transcriptional modules implicated in anti-microbial responses, IL22 also coordinated an endoplasmic reticulum (ER) stress response transcriptional program in colonic epithelial cells. In the colon of patients with active colonic Crohn’s disease (CD), there was enrichment of IL22-responsive transcriptional modules and ER stress response modules. Strikingly, in an IL22-dependent model of chronic colitis, targeting IL22 alleviated colonic epithelial ER stress and attenuated colitis. Pharmacological modulation of the ER stress response similarly impacted the severity of colitis. In patients with colonic CD, antibody blockade of IL12p40, which simultaneously blocks IL12 and IL23, the key upstream regulator of IL22 production, alleviated the colonic epithelial ER stress response. Conclusions- Our data challenge perceptions of IL22 as a predominantly beneficial cytokine in IBD and provide novel insights into the molecular mechanisms of IL22-mediated pathogenicity in chronic colitis. Targeting IL22 regulated pathways and alleviating colonic epithelial ER stress may represent promising therapeutic strategies in patients with coliti