Is there any correlation between otitis media and dental malocclusion in children? A systematic review

PurposeThis study aims to evaluate whether there is a correlation between otitis and dental malocclusions.MethodsElectronic databases were searched for observational studies published until July 2021 without language or time restrictions. PROSPERO: CRD42021270760. Observational studies on children with and without OM and/or malocclusion were included. After removing duplicates and excluding not-eligible articles, two reviewers screened relevant articles independently. Two reviewers independently extracted data and assessed data quality and validity through the Newcastle-Ottawa Scale (NOS) quality assessment tool for non-randomized studies.ResultsFive studies met the selection inclusion criteria and were included in the studies for a total of 499 patients. Three studies investigated the relationship between malocclusion and otitis media, while the remaining two studies analyzed the inverse relationship and one of them considered eustachian tube dysfunction as a proxy of OM. An association between malocclusion and otitis media and vice versa emerged, although with relevant limitations.ConclusionThere is some evidence that there is an association between otitis and malocclusion; however, it is not yet possible to establish a definitive correlation

OPT3 is a component of the iron-signaling network between leaves and roots and misregulation of OPT3 leads to an over-accumulation of cadmium in seeds.

Plants and seeds are the main dietary sources of zinc, iron, manganese, and copper, but are also the main entry point for toxic elements such as cadmium into the food chain. We report here that an Arabidopsis oligopeptide transporter mutant, opt3-2, over-accumulates cadmium (Cd) in seeds and roots but, unexpectedly, under-accumulates Cd in leaves. The cadmium distribution in opt3-2 differs from iron, zinc, and manganese, suggesting a metal-specific mechanism for metal partitioning within the plant. The opt3-2 mutant constitutively up-regulates the Fe/Zn/Cd transporter IRT1 and FRO2 in roots, indicative of an iron-deficiency response. No genetic mutants that impair the shoot-to-root signaling of iron status in leaves have been identified. Interestingly, shoot-specific expression of OPT3 rescues the Cd sensitivity and complements the aberrant expression of IRT1 in opt3-2 roots, suggesting that OPT3 is required to relay the iron status from leaves to roots. OPT3 expression was found in the vasculature with preferential expression in the phloem at the plasma membrane. Using radioisotope experiments, we found that mobilization of Fe from leaves is severely affected in opt3-2, suggesting that Fe mobilization out of leaves is required for proper trace-metal homeostasis. When expressed in yeast, OPT3 does not localize to the plasma membrane, precluding the identification of the OPT3 substrate. Our in planta results show that OPT3 is important for leaf phloem-loading of iron and plays a key role regulating Fe, Zn, and Cd distribution within the plant. Furthermore, ferric chelate reductase activity analyses provide evidence that iron is not the sole signal transferred from leaves to roots in leaf iron status signaling

Periodic separating reactors: Experiments and theory

The novel combination of a pressure swing adsorber (PSA) with a periodic flow-forced packed-bed reactor is explored. The device provides integral component separation and reaction. Feed sequences studied for the periodic separating reactor (PSR) were those of rapid, single-bed pressure swing adsorption (RPSA). The experimental investigation employed CO oxidation over a packed bed of supported platinum catalyst and molecular sieve adsorbent. A reaction rate limited model is formulated and solved for a variety of irreversible and reversible reactions. The presence of irreversible chemical reaction is shown to greatly enhance the separation achievable by RPSA alone. For a wide range of inlet CO/O 2 ratios, CO 2 production could be increased up to two times over steady-state plug-flow reactor operation, while providing a recycle stream without phase change or extractive procedures. Selectivity and conversion improvements were predicted for multiple reaction systems. Other unusual features of operation, such as separation reversals, were also predicted and observed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/37406/1/690350514_ftp.pd

Equilibrium-limited periodic separating reactors

A new unit operation is presented that utilizes a rapid feed pressure swing cycle in a bed packed with catalyst and adsorbent to effect both reaction and separation. This hybrid device combines features of a cyclic-steady-state pressure swing adsorber with those of a flow-forced catalytic reactor. Feed sequences for the periodic separating reactor (PSR) are those of rapid, single-bed pressure swing adsorbers (PSA). Only the case of extremely fast reactions is considered here. A perturbed reaction-sorption equilibrium model is formulated and solved for isothermal operation for different equilibrium constants and reaction stoichiometries. The capacity and separation performance for an equilibrium-limited PSR (EPSR) can be of the same order of magnitude as PSA alone. For reactions involving a single reactant or single product, the principal component in a particular exit stream depends upon both the reaction stoichiometry and feed fraction of the process cycle. The pressure dependency of the reaction equilibrium expression is the cause of separation reversals as parameters are varied.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/37397/1/690330810_ftp.pd

Rate enhancements and quasi-periodic dynamics during forced concentration cycling of CO and O2 over supported Pt---SnO2

Forced reactant cycling of carbon monoxide-nitrogen and oxygen-nitrogen streams over Pt---SnO2 in a differential reactor results in enhancements of the reaction rate of up to 9 times that of the optimal steady state. Dynamic features common to periodically forced reaction systems were experimentally observed. In addition, quasi-periodic behaviour under forced concentration cycling was also observed. Transient response experiments combined with see-through FTIR analysis confirm an underlying Langmuir-Hinshelwood-type mechanism. Spectral analysis of the quasi-periodic patterns identified at least three time constants of different orders of magnitude. The nature of the patterns also indicated a reaction mechanism which included one or more "reservoirs" of reactants and/or reaction intermediates.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27615/1/0000659.pd

Contribution of Social Isolation, Restraint, and Hindlimb Unloading to Changes in Hemodynamic Parameters and Motion Activity in Rats

The most accepted animal model for simulation of the physiological and morphological consequences of microgravity on the cardiovascular system is one of head-down hindlimb unloading. Experimental conditions surrounding this model include not only head-down tilting of rats, but also social and restraint stresses that have their own influences on cardiovascular system function. Here, we studied levels of spontaneous locomotor activity, blood pressure, and heart rate during 14 days under the following experimental conditions: cage control, social isolation in standard rat housing, social isolation in special cages for hindlimb unloading, horizontal attachment (restraint), and head-down hindlimb unloading. General activity and hemodynamic parameters were continuously monitored in conscious rats by telemetry. Heart rate and blood pressure were both evaluated during treadmill running to reveal cardiovascular deconditioning development as a result of unloading. The main findings of our work are that: social isolation and restraint induced persistent physical inactivity, while unloading in rats resulted in initial inactivity followed by normalization and increased locomotion after one week. Moreover, 14 days of hindlimb unloading showed significant elevation of blood pressure and slight elevation of heart rate. Hemodynamic changes in isolated and restrained rats largely reproduced the trends observed during unloading. Finally, we detected no augmentation of tachycardia during moderate exercise in rats after 14 days of unloading. Thus, we concluded that both social isolation and restraint, as an integral part of the model conditions, contribute essentially to cardiovascular reactions during head-down hindlimb unloading, compared to the little changes in the hydrostatic gradient

On the characterization of the heterogeneous mechanical response of human brain tissue

The mechanical characterization of brain tissue is a complex task that scientists have tried to accomplish for over 50 years. The results in the literature often differ by orders of magnitude because of the lack of a standard testing protocol. Different testing conditions (including humidity, temperature, strain rate), the methodology adopted, and the variety of the species analysed are all potential sources of discrepancies in the measurements. In this work, we present a rigorous experimental investigation on the mechanical properties of human brain, covering both grey and white matter. The influence of testing conditions is also shown and thoroughly discussed. The material characterization performed is finally adopted to provide inputs to a mathematical formulation suitable for numerical simulations of brain deformation during surgical procedures.</p