Eshelby's problem of a spherical inclusion eccentrically embedded in a finite spherical body.

Resorting to the superposition principle, the solution of Eshelby's problem of a spherical inclusion located eccentrically inside a finite spherical domain is obtained in two steps: (i) the solution to the problem of a spherical inclusion in an infinite space; (ii) the solution to the auxiliary problem of the corresponding finite spherical domain subjected to appropriate boundary conditions. Moreover, a set of functions called the sectional and harmonic deviators are proposed and developed to work out the auxiliary solution in a series form, including the displacement and Eshelby tensor fields. The analytical solutions are explicitly obtained and illustrated when the geometric and physical parameters and the boundary condition are specified.

Environmental tobacco smoke exposure, urine CC-16 levels, and asthma outcomes among Chinese children.

BACKGROUND: Previous studies have shown the relationship between club cell secretory protein (Clara) (CC-16) and respiratory diseases. However, few studies have explored the associations between urine CC-16 levels and environmental tobacco smoke (ETS) exposure in children. The objective of this study was to evaluate whether ETS exposure is associated with CC-16 when stratified by asthma status. METHODS: In our study, CC-16 was measured on 537 children aged 9-15 from northeast China in 2011-2012 using the Human Clara Cell Protein ELISA kits. Doctor-diagnosed asthma was defined as having ever been diagnosed with asthma by a physician. The relationship between ETS exposure and urine CC-16 level was assessed using linear regression. RESULTS: When stratified by asthma status, a negative association between ETS exposure and urine CC-16 was observed after adjusting for the effects of the related covariates, with an adjusted ß coefficient [P value] = -0.31 [0.006] in the first 2 years of life and with an adjusted ß coefficient [P value] = -0.68 [0.004] in the first 2 years of life and current. CONCLUSIONS: Our study shows long-term exposure to ETS was associated with urinary CC-16 among children without asthma.

Analyzing the interplay between single cell rheology and force generation through large deformation finite element models.

In this study, experimental results of single cell spreading between two parallel microplates are exploited through finite element modeling. Axisymmetric computations at finite strains are performed to extract the mechanical properties of the cell which can account for cell shape evolution and traction force generation. Our model includes two distinct components representing the cortex associated with the bilayer membrane on the one hand, and the rest of the cell on the other hand. The former is modeled as a homogeneous hyperelastic material described by a slightly compressible Gent strain energy function, while the latter is idealized either as a quasi-incompressible Newtonian fluid or as another homogeneous hyperelastic material. The kinetics of spreading is ensured by a stapling procedure defined from experimental observations. Material parameters are then optimized to match the simulation closely with the experimental data. In particular, the elastic modulus of the cortex is estimated at about 1,000 Pa in both models, while the cell interior is characterized by a viscosity of 1,000 Pa.s in the biphasic model, or by an elastic modulus of about 100 Pa in the hyperelastic one. These results are in good agreement with G(') and G('') measurements carried out previously in the same parallel plates setup and estimated at the typical rate of cell straining. Moreover, stresses are found to concentrate at the edge of the cell-substrate contact area. These observations allow explaining the relationship between cell spreading and force increase since spreading and the consequent straining of the cell mechanical structure could be the source of the force applied by the cell on its substrate. They could also explain, in a very simple manner, why force-sensitive focal contacts concentrate at the cell edges.

Towards an elastic model of wurtzite AlN nanowires.

Starting with ab initio calculations of AlN wurtzite [0001] nanowires with diameters up to 4 nm, a finite element method is developed to deal with larger nanostructures/nanoparticles. The ab initio calculations show that the structure of the nanowires can be well represented by an internal part with AlN bulk elastic properties, and one atomic surface layer with its own elastic behavior. The proposed finite element method includes surface elements with their own elastic properties using surface elastic coefficients deduced from the ab initio calculations. The elastic properties obtained with the finite element model compare very well with those obtained with the full ab initio calculations.

Pets keeping in home, parental atopy, asthma, and asthma-related symptoms in 12,910 elementary school children from northeast China.

UNLABELLED: The effects of pet exposure and parental atopy on respiratory symptoms were investigated in 12,910 children residing in twelve districts of northeast China. Responses to a self-administered questionnaire completed by parents of children were used to ascertain children with persistent cough, persistent phlegm, doctor-diagnosed asthma, current asthma and current wheeze. Exposure to animals during pregnancy was positively associated with doctor-diagnosed asthma [adjusted odds ratio (ORs), 1.86; 95% confidence interval (CI) 1.35-2.57], current asthma (adjusted OR, 3.06; 95% CI, 1.95-4.81) and asthma-related symptoms. Pet exposure in the first year of life and currently having animals in household were also related to a significantly higher prevalence of doctor-diagnosed asthma and asthma-related symptoms in these children. Associations with respiratory symptoms strengthened with higher levels of animal exposure. Parental atopy increased the risk of asthma diagnosis (OR, 3.49; 95%CI, 2.84-4.30), current asthma (OR, 3.94; 95%CI, 2.81-5.54) and asthma-related symptoms. There was an interaction between parental atopy and pet exposure in persistent phlegm, but not in doctor-diagnosed asthma. We conclude that pet keeping and parental atopy increased the risk of respiratory symptoms in children. Parental atopy did modify the effect of pet exposure on persistent phlegm but not on doctor-diagnosed asthma. PRACTICAL IMPLICATIONS: The relationship between exposure to animals and allergic respiratory diseases in childhood is controversial. Inconsistent with other cross-sectional studies mostly conducted in industrialized countries, our study indicates that exposure to animals may increase the occurrence of respiratory symptoms and diseases in children, and the associations with respiratory symptoms strengthened with higher levels of animal exposure parental atopy did modify the effect of pet exposure on persistent phlegm but not on doctor-diagnosed asthma. These findings support the view that measures should be taken to reduce animal exposure for children in China.

Effects of environmental tobacco smoke on respiratory health of boys and girls from kindergarten: results from 15 districts of northern China.

UNLABELLED: The effects of childhood environmental tobacco smoke (ETS) exposure on respiratory symptoms were investigated in 6053 kindergarten-aged children residing in 15 districts of northern China. Responses to a self-administered questionnaire completed by parents of children from 30 kindergartens were used to ascertain children with persistent cough, persistent phlegm, asthma symptom, current asthma, wheeze and wheeze without asthma. In first 2 years ETS exposure and current ETS exposure were associated with increased prevalence of persistent cough, persistent phlegm, wheeze and wheeze without asthma. Among boys, ETS exposure was associated with more respiratory symptoms and diseases than in girls. ETS exposure during pregnancy was associated with asthma symptom [odds ratio (OR), 3.00; 95% confidence interval (CI): 1.28-7.03], current asthma (OR, 3.38; 95% CI: 1.25-9.14), persistent cough (OR, 1.64; 95% CI: 1.13-2.37), persistent phlegm (OR, 1.74; 95% CI: 1.01-3.01), wheeze (OR, 1.75; 95% CI: 1.15-2.68), and wheeze without asthma (OR, 1.46; 95% CI: 1.01-2.37) only among boys. In boys, the adjusted ORs for increased risk of asthma symptom and current asthma for household exposures (> or =10 cigarettes smoked per day vs. none smoked) during workday were 2.04 (95% CI: 1.01-3.89) and 2.76 (95% CI: 1.06-9.58), respectively. We conclude that ETS exposure increases the occurrence of respiratory symptoms and diseases during childhood. Boys may be more susceptible to ETS than girls. PRACTICAL IMPLICATIONS: Environmental tobacco smoke (ETS) is a highly prevalent respiratory irritant. In agreement with previous cross-sectional studies, our study indicates that exposure to ETS may increase the occurrence of respiratory symptoms and diseases in children, and the association of ETS exposure and respiratory health of children increased in strength with number of cigarettes smoked inside the house per day during workday and day-off. Boys may be more susceptible to ETS than girls. These findings support the view that measures should be taken to reduce ETS exposure for children.

Effects of environmentally realistic levels of ozone on stratum corneum function.

The impact of troposphere ozone (O(3)), the major oxidant in photochemical smog, on the overall wellbeing of skin is of considerable interest. To date, limited information is available on the impact of O(3) on human skin. Using a specially designed O(3) exposure chamber, we provide the first evidence that exposure of human skin to O(3) (0.8 ppm, 2-h time-weighted average) significantly reduced vitamin E by 70% and concomitantly increased lipid hydroperoxides by 2.3 fold in the superficial stratum corneum (SC). Although the dose of O(3) used here reduced the resident microflora population by 50% and created a state of oxidative stress within the SC, it did not affect several key enzymes involved in SC homeostasis including the redox-sensitive transglutaminase and the SC tryptic (KLK5) and chymotryptic (KLK7) proteases. Importantly, no signs of skin dryness or erythema were observed. We hypothesize that the limited effects of low doses of O(3) on SC function is attributable to several factors including: (i) protection provided by the anti-oxidant defence system; (ii) inability of O(3) to penetrate the SC; and (iii) limited water available to catalyse the Criegee reaction. Although chronic exposure to O(3) may produce a different outcome than that reported here, our data suggest that exposure to environmentally relevant doses of O(3), at best, induces a moderate state of oxidative stress, without producing a visible clinical response. In our opinion, exposure of skin to UV radiation is a much more significant threat than exposure to ground-level O(3).

Tensile and compressive stress yield criteria for cancellous bone.

Experimentally based isotropic tensile and compressive strain yield criteria for cancellous bone are shown to imply tensile and compressive stress yield criteria, respectively. In particular, it is deduced that the directional variation of uniaxial yield stress is proportional to the one of Young's modulus. The obtained tensile and compressive stress yield criteria, in turn, imply information about the total stress yield criterion for cancellous bone.

The use of ozone as an oxidizing agent to evaluate antioxidant activities of natural substrates.

Ozone, the main component of photochemical smog and air pollution, can damage the skin by oxidizing stratum corneum enzymes, lipids and structural proteins. We have developed a rapid screening assay to determine free radical scavenging capacity of various active ingredients that are frequently used in personal care products. Several known antioxidants including vitamin C, vitamin E analog Trolox, walnut seed extract, lipoic acid and ergothioneine inner salt were assayed for their ability to neutralize ozone-induced oxidation of beta-phycoerythrin, a fluorescent reporter protein derived from algae. The free radical scavenging capacities of these antioxidants were quantified and compared. The results demonstrate that this assay is a valuable primary screening tool for identifying antioxidant activity of natural or synthetic substrates that can be used in personal care products to protect the uppermost layer of our skin from oxidizing damage induced by O3.

Right ventricular and septal anomalies complicated by subacute bacterial endocarditis.

We report the case of a 31-year-old woman with no history of heart disease. She came to the hospital with fever, dyspnea, palpitation, and edema of the lower extremities. She was found to have aortic, mitral, and pulmonary valve insufficiency, and the initial diagnosis was subacute bacterial endocarditis. At surgery, we replaced the aortic and mitral valves with mechanical prostheses and the pulmonary valve with a bioprosthesis. The prostheses were soaked intraoperatively with fluconazole and the heart chambers were irrigated with povidone-iodine to prevent infection by bacteria and fungi. We also found 2 previously unsuspected anomalies: 1 was a muscular bundle that divided the right ventricle into 2 chambers, and the other was a ventricular septal defect, 1.0 cm in diameter. We resected the muscular bundle and patched the septal defect. The patient had an uneventful postoperative course and was in New York Heart Association functional class I at the 15-month follow-up visit. We speculate that this patient's congenital anomalies made the heart more susceptible to damage from the endocarditis. Therefore, any patient who has infective endocarditis should also be examined closely for congenital defects.

Open-heart surgery in 48 patients via a small right anterolateral thoracotomy.

To limit the trauma to the chest and to achieve a pleasing cosmetic result, we used 2 types of right anterolateral thoracotomy in 48 patients who required open-heart surgery: 1 was a curved incision along the lower edge of the right breast in women with developed breasts; the other was a slanted incision for men and children. These surgical procedures took place between July 1996 and November 1997. Intraoperatively, a right atriotomy was used to repair 11 atrial septal defects and 11 ventricular septal defects, 2 combined atrial and ventricular septal defects, 1 case of a single atrium, and 1 partial atrioventricular canal. A right ventricular outflow tract incision was used to repair 7 ventricular septal defects and 7 ruptured aortic sinus aneurysm. A combination of a right atriotomy and right ventricular outflow tract incision was used for 2 repairs of combined atrial and ventricular septal defects, 3 radical corrections of tetralogy of Fallot, and 2 radical corrections of trilogy of Fallot. A combined right and interatrial septal incision was used for 6 mitral valve replacements and 1 mitral valvuloplasty. Smooth bypass cannulation and satisfactory intracardiac exposure were achieved with the right anterolateral thoracotomy. There was no complication or mortality directly related to the incision. We believe that the right anterolateral thoracotomy is safer and more effective than the median sternotomy for many common congenital and acquired heart diseases. The thoracotomy causes less trauma and results in a cosmetic appearance that is more acceptable to the patient.

Explanation by a putative triester-like mechanism for the thio effects and Mn2+ rescues in reactions catalyzed by a hammerhead ribozyme.

Divalent metal ion-dependent hammerhead ribozymes can cleave any RNA with a NUX triplet, wherein the N can be any residue and X can be C, U or A. In recent literature on the mechanism of action of hammerhead ribozymes, one important role of divalent metal ions is generally suggested to be an electrophilic catalyst by directly coordinating with the pro-Rp oxygen of the scissile phosphate to stabilize the transition state. This proposal was made on the basis of thio effects and the proposed electrophilic catalyst is very attractive as an explanation for the catalytic activity of metalloenzymes. Reexamination of thio effects with substrates having a GUA triplet at the cleavage site shows that, in agreement with the previous finding, the cleavage rate, in the presence of Mg2+ ions, is significantly reduced in the case of the phosphorothioate substrate (RpS), wherein the pro-Rp oxygen at the scissile phosphate is replaced by sulfur, while the cleavage rate is reduced to a much lesser extent for the other isomer (SpS), wherein the pro-Sp oxygen at the scissile phosphate is replaced by sulfur. However, more careful examination of the rescue ability of Mn2+ ions with these isomers demonstrates that more thiophilic Mn2+ ions rescue the reaction not only with the RpS isomer but also with the SpS isomer and, importantly, to a greater extent for the SpS isomer. These results argue against the previous conclusion that a metal ion is directly coordinating with the pro-Rp oxygen of the scissile phosphate to stabilize the transition state. In this paper we try to elucidate the possible origin of the thio effects and propose a 'triester-like' mechanism in reactions catalyzed by hammerhead ribozymes.

Effects of air pollution on children's pulmonary function in urban and suburban areas of Wuhan, People's Republic of China.

In May and June of 1988, the spirometric lung function of 604 children, who were aged 7-13 y and who were free of chronic respiratory conditions, was measured in the urban core and a suburb of Wuhan, China. During 1981-1988, ambient total suspended particulate (TSP) levels averaged 481 micrograms/m3 in the urban core and 167 micrograms/m3 in the suburb. In 1988, TSP levels, measured within 500 m of the children's homes, averaged 251 micrograms/m3 in the urban core and 110 micrograms/m3 in the suburb. Levels of sulfur dioxide and nitrogen oxides were also higher in the urban core. Proportions of families who burned coal and gas domestically were similar in both areas. In linear and logarithmic regression models, height was a stronger determinant of forced vital capacity and forced expiratory volume in 1 s than was age or weight. In linear models, the proportion of variance explained by height (R-squared) ranged from 0.54 for urban females' forced expiratory volume in 1 s to 0.77 for suburban males and females. Both forced vital capacity and forced expiratory volume in 1 s were consistently lower in urban than suburban children. The average forced vital capacity and forced expiratory volume in 1 s in children 132-144 cm tall were 6.7% and 3.8% lower, respectively, in the urban core than the suburb; suburban-urban differences increased with height. Suburban-urban differences in slopes of lung function growth curves were statistically significant for forced vital capacity but not for forced expiratory volume in 1 s. Rates of clinical upper respiratory irritation were also generally elevated in urban children. These results strongly suggest that urban ambient air pollution exposure in China contributes to retardation in the growth of children's lung function. Confirmatory longitudinal studies are in progress in Wuhan and three other Chinese cities.

Highly sensitive polarization-controlled optical switching with a photorefractive double phase conjugator.

Highly sensitive polarization-controlled optical switching is demonstrated experimentally through a photorefractive BaTiO(3) double-phase-conjugate mirror. A theoretical explanation is developed, and possible applications are mentioned.

Wavefront conjugation and amplification for optical communication through distorting media: experiment.

The laboratory performance of recently proposed new architectures for optical communication through distorting media is investigated. After phase-conjugating a weak beam with a mutually incoherent source a power amplification with a gain factor of 500 was demonstrated. The amplified beam can be employed for distortion-free optical communication by direct signal transmission. In a different configuration, wavefront matching applicable for coherent detection is proved to be feasible.