Cooperative sequential-adsorption model in two dimensions with experimental applications for ionic self-assembly of nanoparticles.

Self-assembly of nanoparticles is an important tool in nanotechnology, with numerous applications, including thin films, electronics, and drug delivery. We study the deposition of ionic nanoparticles on a glass substrate both experimentally and theoretically. Our theoretical model consists of a stochastic cooperative adsorption and evaporation process on a two-dimensional lattice. By exploring the relationship between the initial concentration of nanoparticles in the colloidal solution and the density of particles deposited on the substrate, we relate the deposition rate of our theoretical model to the concentration.

Repeated high-speed activities during youth soccer games in relation to changes in maximal sprinting and aerobic speeds.

The aim of this study was to examine in highly-trained young soccer players whether substantial changes in either maximal sprinting speed (MSS) or maximal aerobic speed (as inferred from peak incremental test speed, V(Vam-Eval)) can affect repeated high-intensity running during games. Data from 33 players (14.5±1.3 years), who presented substantial changes in either MSS or V(Vam-Eval) throughout 2 consecutive testing periods (~3 months) were included in the final analysis. For each player, time-motion analyses were performed using a global positioning system (1-Hz) during 2-10 international club games played within 1-2 months from/to each testing period of interest (n for game analyzed=109, player-games=393, games per player per period=4±2). Sprint activities were defined as at least a 1-s run at intensities higher than 61% of individual MSS. Repeated-sprint sequences (RSS) were defined as a minimum of 2 consecutive sprints interspersed with a maximum of 60 s of recovery. Improvements in both MSS and V(Vam-Eval) were likely associated with a decreased RSS occurrence, but in some positions only (e. g., - 24% vs. - 3% for improvements in MSS in strikers vs. midfielders, respectively). The changes in the number of sprints per RSS were less clear but also position-dependent, e. g., +7 to +12% for full-backs and wingers, - 5 to - 7% for centre-backs and midfielders. In developing soccer players, changes in repeated-sprint activity during games do not necessarily match those in physical fitness. Game tactical and strategic requirements are likely to modulate on-field players' activity patterns independently (at least partially) of players' physical capacities.

Match running performance and fitness in youth soccer.

The activity profiles of highly trained young soccer players were examined in relation to age, playing position and physical capacity. Time-motion analyses (global positioning system) were performed on 77 (U13-U18; fullbacks [FB], centre-backs [CB], midfielders [MD], wide midfielders [W], second strikers [2 (nd)S] and strikers [S]) during 42 international club games. Total distance covered (TD) and very high-intensity activities (VHIA; >16.1 km·h (-1)) were computed during 186 entire player-matches. Physical capacity was assessed via field test measures (e. g., peak running speed during an incremental field test, VVam-eval). Match running performance showed an increasing trend with age ( P<0.001, partial eta-squared (η (2)): 0.20-0.45). When adjusted for age and individual playing time, match running performance was position-dependent ( P<0.001, η (2): 0.13-0.40). MD covered the greater TD; CB the lowest ( P<0.05). Distance for VHIA was lower for CB compared with all other positions ( P<0.05); W and S displayed the highest VHIA ( P<0.05). Relationships between match running performance and physical capacities were position-dependent, with poor or non-significant correlations within FB, CB, MD and W (e. g., VHIA vs. VVam-eval: R=0.06 in FB) but large associations within 2 (nd)S and S positions (e. g., VHIA vs. VVam-eval: R=0.70 in 2 (nd)S). In highly trained young soccer players, the importance of fitness level as a determinant of match running performance should be regarded as a function of playing position.

Repeated-sprint sequences during youth soccer matches.

This study examined the occurrence and nature of repeated-sprint sequences (RSS) in highly-trained young soccer players, as a function of age, playing position and playing time. Time-motion analyses using a global positioning system (GPS) were performed on 99 highly-trained young soccer (U13, U14, U15, U16, U17 and U18) players during 42 international games. Sprint activities were defined as at least a 1-s run at intensities higher than 61% of the individual peak running velocity; RSS, as a minimum of 2 consecutive sprints interspersed with a maximum of 60 s. During the first half of games the younger teams had a greater number of RSS than the older teams (P<0.001): U13>U14>U16>U15>U18>U17. The younger players also performed more (e. g., U14 vs. U17: 2.8±0.3 vs. 2.6±0.3, P<0.05) and longer (e. g., U14 vs. U17: 2.8±0.5 vs. 2.6±0.5 s, P<0.05) sprints per sequence than the older players. RSS occurrence was also affected by playing position and decreased throughout the game in most age-groups (P<0.001). Both the occurrence and the nature of RSS are affected by age, position and playing time. Present results also question the importance of repeated-sprint ability as a crucial physical component of soccer performance in developing players.

Decreased prevalence of sensitization to cats with high exposure to cat allergen.

We investigated the relationship between current exposure to cat allergen and sensitization to cats. A questionnaire was administered and skin prick testing and home visits for collection of dust samples (Fel d 1; ELISA) were performed in 2502 adults (mean age, 31.8 years; age range, 18-58 years; 1251 women). The results for Fel d 1 in relation to sensitization to cats were analyzed for 10 deciles of cat allergen exposure (cut points [microg/g]: 0.05, 0.34, 0.48, 0.72, 1.13, 1.92, 7.2, 44, 151). The prevalence of sensitization to cat was significantly decreased in the lowest and the highest exposure groups. In the multivariate regression analysis (age, sex, socioeconomic status, and current smoking being adjusted for), the risk of sensitization to cats was significantly increased with medium exposure to Fel d 1 (3rd centile, OR 2.3, 95% CI 1.2-4.4, P =.01; 4th centile, OR 2.1, 95% CI 1.1-4.0, P =.03; 5th centile, OR 2.2, 95% CI 1.2-4.3, P =.04, 6th centile, OR 2.5, 95% CI 1.3-4.9, P =.005). These results indicate that the prevalence of sensitization to cat is decreased in the lowest and highest cat allergen exposure groups.

Effect of environmental manipulation in pregnancy and early life on respiratory symptoms and atopy during first year of life: a randomised trial.

BACKGROUND: Asthma places huge demands on health-care services, and its prevalence is increasing. Reduction of exposure to environmental allergens could offer a realistic chance for primary prevention. Our aim was to ascertain whether or not living in a low-allergen environment reduces the risk of asthma and atopic diseases in infants. METHODS: We assigned infants to four risk groups according to parental atopic status. We enrolled 291 high-risk couples (both parents atopic, no pets) into a prospective, prenatally randomised, cohort study, and allocated them to environmental manipulation, in which measures to reduce prenatal and postnatal allergen exposure were undertaken (active HRA) (n=145) or no intervention (control HRC) (n=146). Two further prospective groups were studied: 161 high-risk infants with pets in the home (HRP group) and 168 low-risk infants, whose parents were both non-atopic (LR group). The main outcome measures were signs and symptoms of atopic disease at 1 year of age. FINDINGS: 103 families dropped out or were lost to follow up. At age 1 year we followed-up 133 HRA, 118 HRC, 140 HRP, and 126 LR infants. Children in the HRA group were less likely to have respiratory symptoms during the first year of life than those in the HRC group. The most pronounced differences were in the relative risks for severe wheeze with shortness of breath (relative risk 0.44 [95% CI 0.20-1.00]), prescribed medication for the treatment of wheezy attacks (0.58 [0.36-0.95]), and wheezing after vigorous playing, crying, or exertion (0.18 [0.04-0.79]). Probability of respiratory symptoms in HRC and HRP infants was similar, whereas it was much lower in the LR than in the HRC group. Cat ownership was significantly associated with sensitisation to cats (24.6 [3.04-199.05]; p=0.003). INTERPRETATION: Environmental manipulation reduces some respiratory symptoms in the first year of life in high-risk infants. Further follow up is needed, however, to ascertain whether living in a low-allergen environment reduces allergy and asthma in later life.

Giant cell tumor of the hand: superior results with curettage, cryosurgery, and cementation.

At our institution giant cell tumors arising in all locations are treated with curettage, cryosurgery, and cementation to avoid resection or amputation, increase local tumor control over curettage alone, and avoid the morbidity associated with immobilization. We report the oncologic and functional results of 3 patients with giant cell tumors arising from the tubular bones of the hand who were treated in this manner. At a mean follow-up period of 54 months there were no local recurrences. No patient complained of pain. Digital range of motion and grip strength were within normal limits for all 3 patients. All patients returned to their previous occupational and recreational activities. One instance of minor wound necrosis was successfully treated conservatively. There were no other complications (fractures, infections, neuropraxias, or vascular damage). Curettage, cryosurgery, and cementation performed by experienced surgeons appears to be a safe, effective, and reliable method for treating selected giant cell tumors of the hand.

NAC Manchester Asthma and Allergy Study (NACMAAS): risk factors for asthma and allergic disorders in adults.

Asthma and atopic disorders are the most common chronic diseases in the developed countries. Knowledge of the risk factors for these disorders may facilitate the development of preventive strategies aimed at reducing prevalence rates. To investigate the risk factors for asthma and allergic diseases in a large number of adults who are the parents of children in the National Asthma Campaign Manchester Asthma and Allergy Study. All pregnant women and their partners attending "Booking" antenatal clinics were invited to take part in the study. Questionnaire data were collected including the history of asthma and other atopic diseases, pet ownership and smoking habits, and skin prick tests were performed. The prevalence of atopy and the risk factors for asthma and allergic disorders were investigated in all subjects who completed the questionnaire and underwent skin testing. Statistical analysis was carried out using logistic regression. Initially, risk factors were assessed by univariate analysis to see how each potential explanatory variable affected the probability of having allergic disease. Variables were then tested in a forward stepwise multivariate analysis. In 5687 adult subjects there was a very high (48.2%) prevalence of atopy, and 9.7% of subjects had a diagnosis of asthma. In a multivariate regression analysis sensitization to dust mite, cat, dog and mixed grasses were all independently associated with asthma. The odds ratios for current asthma increased with the increasing number of positive skin tests (any two allergens - OR 4.3, 95% CI 3.3-5.5; any three allergens - OR 7.0 95% CI 5.3-9.3; all four allergens - OR 10.4, 95% CI 7.7-14; P < 0.00001). Dog ownership (OR 1.31, 95% CI 1.10-1.57; P = 0.003) and current smoking (OR 1.36, 95% CI 1.15-1.62; P = 0.0004) were significantly and directly associated with "asthma ever". Thirteen per cent of participants reported a history of eczema. In the multivariate analysis the strongest independent associate of eczema was sensitization to dog (OR 1.37, 95% CI 1.14-1.63, P < 0.0001). Apart from dog, the strength of the association between sensitization to common allergens and eczema appeared to be much lower than in the case of asthma. The prevalence of hay fever was high (20.6%), and in the multivariate analysis the association between sensitization to pollen and hay fever was extremely strong (OR 13.6, 95% CI 11.3-16.3; P < 0.0001). The results of the current study emphasize the importance of sensitization to indoor allergens in asthma. However, evidence of a possible direct role of allergen exposure in asthma causation remains unclear.

Manchester Asthma and Allergy Study: low-allergen environment can be achieved and maintained during pregnancy and in early life.

BACKGROUND: Early exposure to dust mite allergens may be critical for primary sensitization. Reducing exposure may offer a realistic chance for primary prevention of sensitization and asthma, but it is essential to implement measures that can achieve and maintain the low-allergen environment. OBJECTIVE: Our purpose was to assess the effectiveness of mite allergen avoidance measures in achieving and maintaining a low-allergen environment during pregnancy and in the first year of life. METHODS: The Manchester Asthma and Allergy Study is a prospective, prenatally randomized study that follows the development of asthma and atopy in a cohort of infants at high risk (both parents atopic) who are randomly allocated to full mite allergen avoidance or to a normal regimen. Avoidance measures comprise (1) mite-proof covers (mattress, pillow, and quilt) for parental bed, (2) high-filtration vacuum cleaner, (3) vinyl flooring in infant's bedroom, (4) new crib and portable crib mattresses encased in mite-proof material, (5) benzyl benzoate (Acarosan) applied on carpets and soft furniture, (6) bed linens washed in hot water weekly, and (7) washable soft toys. Dust samples from the parental bed, bedroom floor, living room floor, infant's mattress, and nursery floor were collected between the 10th and 14th weeks of pregnancy, immediately after birth, and then at age 6 months and 1 year, and Der p 1 levels were determined by mAb-based ELISA. RESULTS: Recovered Der p 1 from maternal mattress was reduced by 97. 25% (95% confidence interval [CI] 95.25%-98.41%) during the second and third trimesters of pregnancy, with the effect persisting for 6 months (98% reduction, 95% CI 97.25%-99.1%) and 12 months (97.6% reduction, 95% CI 95.7%-98.6%) after the birth (active vs control, P <.000001). Total Der p 1 from bedroom floor in the active group was reduced by 53.7% (95% CI 25.7%-71.2%) in samples collected within 4 weeks of the child's birth, with the percentage reduction being 62. 8% (95% CI 39.3%-77.2%) at 6 months and 26.5% (95% CI -24% to 57.1%) at 1 year (active compared vs control, P <.007). Der p 1 levels in crib mattress and nursery floor in the active group were extremely low (crib mattresses geometric mean [95% CI] 2.3 ng [1.6-3.4] at birth, 6.8 ng [4.5-10] at age 6 months, and 15.6 ng [9.8-24.8] at age 1 year [active vs control, P =.001]; nursery 1 ng [0.9-1.1] at birth, 1.7 ng [1.2-2.5] at age 6 months, and 2 ng [1.3-3.5] at age 1 year [active vs control, P <.00001]). The total amount of allergen recovered at age 1 year was 29-fold (95% CI 15.1- to 56.7-fold) higher in the control group than in the active group. CONCLUSIONS: The avoidance measures used in this study achieved and maintained a low mite allergen environment during pregnancy and in the first year of life in homes of infants at risk of atopy.

Extended criteria for cardiac allograft donors: a consensus study.

BACKGROUND AND METHODS: To achieve a consensus regarding extending the current criteria for referring potential cardiac allograft donor, we sent a detailed questionnaire to all heart transplant surgeons in the United Kingdom. RESULTS: Replies representing the opinion of 16 heart transplant surgeons (88% response rate) suggest that the majority believe that donor age could be extended up to 55 years even in the absence of a coronary angiogram or echocardiogram. Family history of ischemic heart disease, history of hyperlipidemia or smoking, and brain death caused by paracetamole or barbiturates overdose were not considered prohibitive to cardiac allograft donation. Similarly, chest trauma, prolonged mechanical ventilation, pre-referral cardiac arrest or hypotension for any length of time, and nonspecific ST-segment elevation were not considered to be contraindications. By contrast, significant Q waves in a recent electrocardiogram, the presence of hepatitis C antibodies, pulmonary capillary wedge pressure more than 20 mm Hg, and dependency on multiple inotropic support were considered definite exclusion criteria. Donor hormonal resuscitation (T3-cocktail), insertion of a Swan-Ganz catheter, and direct measurement of intracavitary pressure at the time of retrieval were considered unnecessary by more than 80% of respondents. There was no consensus of opinion regarding the use of donors above the age of 55 years, brain death caused by carbon monoxide poisoning, history of diabetes mellitus, alcohol or drug abuse, systemic infections, electrocardiographic evidence of left ventricular hypertrophy, or the maximum dose of inotropic support required to maintain satisfactory hemodynamics. CONCLUSIONS: The number of potential cardiac allograft donors can be increased by extending the donor age to 55 years. Brain death caused by Paracetamole and barbiturate overdose may not prohibit organ donation.