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This study aimed to assess the potential role of pneumatisation of the mastoid and its communicating air cells in the development of middle-ear barotrauma in aircrew members.
Seventy-nine aircrew members (158 ears) underwent temporal computed tomography. All were assessed before flying by clinical examination and audiology evaluation, followed by post-flight examination to detect barotrauma.
Aircrew members’ ears were divided into 3 groups based on barotrauma and temporal bone pneumatisation: 33 ears with barotrauma and temporal bone pneumatisation of 71 cm3 or greater (group A); 12 ears with barotrauma and temporal bone pneumatisation of 11.2 cm3 or lower (group B); and 113 ears with no barotrauma (group C). Mean pneumatisation volumes were 91.05 cm3, 5.45 cm3 and 28.01 cm3 in groups A, B and C, respectively. A direct relationship was observed between volume of temporal bone pneumatisation of 71 cm3 or greater and barotrauma grade.
Pneumatisation volume of the mastoid and its communicating air cells that ranges from 11.3 cm3 to 70.4 cm3 serves as a reliable predictor of the avoidance of middle-ear barotrauma associated with flying in aircrew members who have normal resting middle-ear pressure and good Eustachian tube function.
To evaluate the effects of oral steroids alone or followed by intranasal steroids versus watchful waiting on the resolution of otitis media with effusion in children aged 2–11 years.
A total of 290 children with bilateral otitis media with effusion were assigned to 3 groups: group A was treated with oral steroids followed by intranasal steroids, group B was treated with oral steroids alone and group C was managed with watchful waiting. Patients were evaluated with audiometry and tympanometry.
The complete resolution rates of otitis media with effusion were higher in groups A and B than in group C at six weeks. There were no significant differences in otitis media with effusion resolution rates between the groups at three, six and nine months.
Oral steroids lead only to a quick resolution of otitis media with effusion, with no long-term benefits. There was no benefit of using intranasal steroids in the management of otitis media with effusion.
The objective of the present study was to investigate live weight (LW) gain, urinary nitrogen (UN) excretion and urination behaviour of dairy heifers grazing pasture, chicory and plantain in autumn and spring. The study comprised a 35-day autumn trial (with a 7-day acclimation period) and a 28-days spring trial (with a 7-day acclimation period). For each trial, 56 Friesian × Jersey heifers were blocked into five dietary treatments balanced for their LW and breeding worth (i.e. genetic merit of a cow for production and reproduction): 1·00 perennial ryegrass–white clover pasture (PA); 1·00 chicory (CH); 1·00 plantain (PL); 0·50 pasture + 0·50 chicory (PA + CH); and 0·50 pasture + 0·50 plantain (PA + PL). A fresh allocation of the herbage was offered every 3 days with allowance calculated according to feed requirement for maintenance plus gain of 1·0 kg LW/day. In both trials, LW gain was lower on CH than other treatments. In the spring trial, UN concentration and UN excretion were lower in CH and PL than other treatments. In autumn, a higher urination frequency was observed over the first 6 h after forage allocation in CH and PA + CH than other treatments. Data from the present study indicate that feeding CH alone limited heifer LW gain. However, heifers grazing swards containing chicory (CH and PA + CH) and plantain (PL and PA + PL) had the potential to lower nitrous oxide emissions and nitrate leaching from soil compared with heifers grazing PA, by reducing N loading in urine patches.
Various variables that might influence the rapid and sustained virological response to recombinant PEG-IFN-α-2a were explored in Iraqi HCV-infected patients with haemoglobinopathy. Forty-three patients were evaluated for the relationship between rapid virological response (RVR), IL-28B polymorphism, viral load, liver enzyme levels, blood group, ultrasound findings, or HCV genotype and the sustained virological response (SVR) achievement. The overall RVR was 55·81% while the overall SVR was 53·49%. SVR in patients that achieved RVR was 82·61% (P = 0·0004). A significant association was found between initial alanine transaminase levels and viral load with SVR achievement (P = 0·025) and (P = 0·004), respectively. Thirty-two (74%) out of 43 of our samples were host genotyped at the IL-28B locus as CC, a significant association was found between CC group and SVR achievement (P = 0·04). Of our samples, 23/43 (53%) were typed as HCV genotype 4, 10/43 (23%) as genotype 1, 9/43 (20·9%) as genotype 3 and 1/43 (2·3%) as genotype 2. A significant association was found between genotype 3 and SVR achievement (P = 0·006). Multivariate analysis showed that only RVR achievement independently associated with SVR in the Iraqi population (P = 0·00). These results can be used to classify the patients requiring the more expensive new direct-acting antiviral drugs.
Structural materials in the new Generation IV reactors will operate in harsh radiation conditions coupled with high levels of hydrogen and helium production and will experience severe degradation of mechanical properties. Therefore, understanding of the physical mechanisms responsible for the microstructural evolution and corresponding mechanical property changes is critical. As the involved phenomena are very complex and span in several length scales, a multiscale approach is necessary in order to fully understand the degradation of materials in irradiated environments. In previous work, we used molecular dynamics simulations to develop critical rules for the mobility of dislocations in various iron alloys and their interaction with several types of defects that include, among others, helium bubbles and grain boundaries. In this work, Dislocation Dynamics simulations of iron alloys are used to study the mechanical behavior and the degradation under irradiation of large systems with high dislocation and defect densities.
A total of 3961 married couples from six major geographical areas representing the South Sinai governorates in Egypt were studied to assess the rate of consanguineous marriage. The population of six selected areas (St Catherines, Nuweiba, Abu Rudeis, Ras Sudr, El Tor and Abu Zenima) were subdivided into Bedouin, urban and mixed populations. A questionnaire-based interview was conducted showing that the consanguinity rate in this region is 37.5%, with the highest rate recorded in Abu Rudeis (52.3%) and lowest rate in Nuweiba (24.1%). Consanguinity was significantly higher among the Bedouin population compared with the urban population in Abu Rudeis, Ras Sudr, El Tor and Abu Zenima, while in St Catherines and Nuweiba there was no statistically significant difference. Among consanguineous couples, 5%, 60% and 35% were double first cousins, first cousins and second cousins respectively. The mean inbreeding coefficient α of the studied population was 0.01845.
The effect of layer thickness on the hardness of nanometallic material composites with both coherent and incoherent interfaces was investigated using nanoindentation. Then, atomistic simulations were performed to identify the critical deformation mechanisms and explain the macroscopic behavior of the materials under investigation. Nanocomposites of different individual layer thicknesses, ranging from 1–30 nm, were manufactured and tested in nanoindentation. The findings were compared to the stress–strain curves obtained by atomistic simulations. The results reveal the role of the individual layer thickness as the thicker structures exhibit somehow different behavior than the thinner ones. This difference is attributed to the motion of the dislocations inside the layers. However, in all cases the hybrid structure was the strongest, implying that a particular improvement to the mechanical properties of the coherent nanocomposites can be achieved by adding a body-centered cubic layer on top of a face-centered cubic bilayer.
A percutaneous in-vig venous model was characterized by testing platelet deposition on standard vascular prosthetic materials in the baboon. The model detected significant difference in platelet deposition on ePTFE compared to Dacron. Low molecular weight dextran was administered following a baseline test period. A significant decrease in platelet depositionr occurred for both materials and coincided with a prolongation in bleeding time. No consistent decrease was found in control experiments which used no bolus or a saline bolus for treatment. Advantages of the model included ease of use and adaptability to test large numbers of materials. The model was suItable for in-vivo screening of platelet interactions with biomaterials placed in the bloodstream.
It is well known that the mechanical behavior of nanoscale multilayered composites is strongly governed by single dislocation mechanisms and dislocation-interface interactions. Such interactions are complex and multiscale in nature. In this work, two such significant effects are modeled within the dislocation dynamics-continuum plasticity framework: elastic properties mismatch (Koehler image forces) and interface shearing in the case of weak interfaces. The superposition principle is used to introduce the stress fields due to both effects solved for by finite elements. The validation of both methodologies is presented. Furthermore, it was found that the layer-confined threading stress of a dislocation in hair-pin configuration increases if the layer is surrounded by layers made of a stiffer material and that this strengthening effect grows more significant as the layer thickness decreases. The observation made through molecular dynamics, that weak interfaces act as dislocation sinks, was also captured with our approach. A dislocation is attracted to the interface independent of its sign or character. Also the force increases sharply as the dislocation approaches the interface. These findings agree with published molecular dynamics simulations and dislocation-based equilibrium models of this type of interaction.
It is shown that, in the case of incidence of p−olarized waves onto a plane- parallel plasma layer, the wave field pressure can cause the electromagnetic field to penetrate into the plasma, which is opaque in the linear approximation for the given waves. The plasma density average over the region of the electromagnetic field does not change.
The propagation of slow surface waves in an inhomogeneous plasma is investigated. Both ‘axial’ and ‘radial’ density gradients n(r) and those of the static magnetic field B0 are taken into account. It is demonstrated that the axial in- homogeneities n(z) and B0(z) result in the dependence of the natural surface- wave frequencies on the ‘axial’ co-ordinate z. The dependence ωSW(z) affects the phase velocity νph = ωswsol;K where K iS the propagation constant. So, in the case of surface-wave excitation by a charged particle beam in an ‘axially’ inhomogeneous plasma, the Cherenkov resonance ωSW= KV0 between the beam and the surface waves breaks, thereby reducing the growth rate of unstable oscillations. This phenomenon might be considered as the stabilization of the beam by the ‘axial’ density gradient. It is also shown that the ‘radial’ gradients n0(r) and B0(r) essentially affect the surface-wave natural frequencies as well. Dispersion equations, expressions for the natural frequencies and growth rates are obtaind, taking into account the gradients of the density and the static magnetic field.
ECT is rarely used as a prophylactic treatment. A 74-year-old woman with unstable bipolar affective disorder receiving maintenance ECT presented a unique opportunity to measure the cognitive effects of continuing ECT.
A single case report with serial psychometric testing during over 400 ECT treatments as a single maintenance treatment.
Serial testing did not demonstrate progressive cognitive deterioration, but consistent cognitive deficits typical of acute treatment were evident. The degree of cognitive difficulty may be related to the frequency of treatment.
Maintenance ECT can be an effective prophylactic treatment for selected patients. Cognitive effects would appear to be no greater than with acute treatment and seem to be non-progressive.
Implantation of the Rashkind double umbrella device for closure of the persistently patent arterial duct is now routine in many units. The use of this device in non-ductal positions, however, has been reported in only a limited number of patients, and its impact on the subsequent clinical course has not been established. A retrospective review of all such occlusions, therefore, was undertaken to address the early results and impact on clinical management. From 9/1988 through 2/1994, implantation of a double umbrella device was attempted in 21 patients (eight female, 13 male) with cardiovascular communications other than a persistent arterial duct excluding the intentional fenestrations made in the modified Fontan procedure. Median age at implantation was 2.6 years (three months-12.4 years) and weight was 11.6 kg (4.1–45) kg. Lesions included four ventricular septal defects, an aortopulmonary window, an aortopulmonary collateral artery, an atrial septal defect, four Gore-tex® shunts, and a residual persistent communication between the superior caval vein and the right atrium following either a bidirectional cavopulmonary anastomosis, or a classical Glenn operation. Eight patients underwent occlusion of unintentional residual right-to-left (six) or left-to-right (two) communications following the Fontan procedure. Implantation was accomplished in all without mortality, utilizing either 12 mm (13) or 17 mm (eight) devices. Surgical removal of the device was required in one patient four weeks subsequent to implantation. At latest follow-up (1–66 months, median four months), color-flow Doppler studies revealed complete occlusion in 17 (77%) patients. Implantation of the double umbrella in sites other than the duct is, therefore, feasible and simplified technically with a modification of the delivery system. Such novel applications of transcatheter intervention using double umbrella devices may avoid or complement subsequent surgery.
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