Holding chambers (spacers) versus nebulisers for beta-agonist treatment of acute asthma

In acute asthma inhaled beta 2-agonists are often administered to relieve bronchospasm by wet nebulisation, but some have argued that metered-dose inhalers with a holding chamber (spacer) can be equally effective. Nebulisers require a power source and need regular maintenance, and are more expensive in the community setting.ObjectivesTo assess the effects of holding chambers (spacers) compared to nebulisers for the delivery of beta 2-agonists for acute asthma.Search strategyWe last searched the Cochrane Airways Group trials register in January 2006 and the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 4, 2005).Selection criteriaRandomised trials in adults and children (from two years of age) with asthma, where spacer beta 2-agonist delivery was compared with wet nebulisation.Data collection and analysisTwo reviewers independently applied study inclusion criteria (one reviewer for the first version of the review), extracted the data and assessed trial quality. Missing data were obtained from the authors or estimated. Results are reported with 95% confidence intervals (CI).Main resultsThis review has been updated in January 2006 and four new trials have been added. 2066 children and 614 adults are now included in 25 trials from emergency room and community settings. In addition, six trials on in-patients with acute asthma (213 children and 28 adults) have been reviewed. Method of delivery of beta 2-agonist did not appear to affect hospital admission rates. In adults, the relative risk of admission for spacer versus nebuliser was 0.97 (95% CI 0.63 to 1.49). The relative risk for children was 0.65 (95% CI: 0.4 to 1.06). In children, length of stay in the emergency department was significantly shorter when the spacer was used, with a mean difference of -0.47 hours (95% CI: -0.58 to -0.37). Length of stay in the emergency department for adults was similar for the two delivery methods. Peak flow and forced expiratory volume were also similar for the two delivery methods. Pulse rate was lower for spacer in children, mean difference -7.6% baseline (95% CI: -9.9 to -5.3% baseline).Authors' conclusionsMetered-dose inhalers with spacer produced outcomes that were at least equivalent to nebuliser delivery. Spacers may have some advantages compared to nebulisers for children with acute asthma

Holding chambers (spacers) versus nebulisers for beta-agonist treatment of acute asthma

Background In acute asthma inhaled beta₂-agonists are often administered by nebuliser to relieve bronchospasm, but some have argued that metered-dose inhalers with a holding chamber (spacer) can be equally effective. Nebulisers require a power source and need regular maintenance, and are more expensive in the community setting. Objectives To assess the effects of holding chambers (spacers) compared to nebulisers for the delivery of beta₂-agonists for acute asthma. Search methods We searched the Cochrane Airways Group Trial Register and reference lists of articles. We contacted the authors of studies to identify additional trials. Date of last search: February 2013. Selection criteria Randomised trials in adults and children (from two years of age) with asthma, where spacer beta₂-agonist delivery was compared with wet nebulisation. Data collection and analysis Two review authors independently applied study inclusion criteria (one review author for the first version of the review), extracted the data and assessed risks of bias. Missing data were obtained from the authors or estimated. Results are reported with 95% confidence intervals (CIs). Main results This review includes a total of 1897 children and 729 adults in 39 trials. Thirty-three trials were conducted in the emergency room and equivalent community settings, and six trials were on inpatients with acute asthma (207 children and 28 adults). The method of delivery of beta₂-agonist did not show a significant difference in hospital admission rates. In adults, the risk ratio (RR) of admission for spacer versus nebuliser was 0.94 (95% CI 0.61 to 1.43). The risk ratio for children was 0.71 (95% CI 0.47 to 1.08, moderate quality evidence). In children, length of stay in the emergency department was significantly shorter when the spacer was used. The mean duration in the emergency department for children given nebulised treatment was 103 minutes, and for children given treatment via spacers 33 minutes less (95% CI -43 to -24 minutes, moderate quality evidence). Length of stay in the emergency department for adults was similar for the two delivery methods. Peak flow and forced expiratory volume were also similar for the two delivery methods. Pulse rate was lower for spacer in children, mean difference -5% baseline (95% CI -8% to -2%, moderate quality evidence), as was the risk of developing tremor (RR 0.64; 95% CI 0.44 to 0.95, moderate quality evidence). Authors' conclusions Nebuliser delivery produced outcomes that were not significantly better than metered-dose inhalers delivered by spacer in adults or children, in trials where treatments were repeated and titrated to the response of the participant. Spacers may have some advantages compared to nebulisers for children with acute asthma

Synthesis, structure and electromagnetic properties of FeCoCu/C nanocomposites

FeCoCu ternary nanoparticles distributed and stabilized in the carbon matrix of FeCoCu/C metal-carbon nanocomposites have been synthesized using controlled IR pyrolysis of precursors consisting of the “polymer / iron acetylacetate / cobalt and copper acetates” type system obtained by joint dissolution of components followed by solvent removal. The effect of the synthesis temperature on the structure, composition and electromagnetic properties of the nanocomposites has been studied. By XRD was shown that the formation of the FeCoCu ternary nanoparticles occurs due to the interaction of Fe3С with the nanoparticles of the CoCu solid solution. An increase in the synthesis temperature leads to an increase in the size of the metal nanoparticles due to their agglomeration and coalescence as a result of matrix reconstruction. Furthermore, ternary alloy nanoparticles having a variable composition may form depending on the synthesis temperature and the content ratio of the metals. Raman spectroscopy has shown that the crystallinity of the carbon matrix of the nanocomposites increases with the synthesis temperature. The frequency responses of the relative permittivity and permeability of the nanocomposites have been studied at 3–13 GHz. It has been shown that a change in the content ratio of the metals noticeably increases both the dielectric and the magnetic losses. The former loss is caused by the formation of a complex nanostructure of the nanocomposite carbon matrix while the latter one originates from an increase in the size of the nanoparticles and a shift of the natural ferromagnetic resonance frequency to the low-frequency region. The reflection loss has been calculated using a standard method from the experimental data on the frequency responses of the relative permittivity and permeability. It has been shown that the frequency range and the absorption of electromagnetic waves (from –20 to –52 dB) can be controlled by varying the content ratio of the metals in the precursor. The nanocomposites obtained as a result of the experiment deliver better results in comparison with FeCo/C nanocomposites synthesized under similar conditions

Learners' decisions for attending Pediatric Grand Rounds: a qualitative and quantitative study

BACKGROUND: Although grand rounds plays a major educational role at academic medical centers, there has been little investigation into the factors influencing the learners' decision to attend. Greater awareness of attendees' expectations may allow grand rounds planners to better accommodate the learners' perspective, potentially making continuing education activities more attractive and inviting. METHODS: We used both qualitative (part A) and quantitative (part B) techniques to investigate the motivators and barriers to grand rounds attendance. Part A investigated contextual factors influencing attendance as expressed through attendee interviews. Transcripts of the interviews were analyzed using grounded theory techniques. We created a concept map linking key factors and their relationships. In part B we quantified the motivators and barriers identified during the initial interviews through a survey of the grand rounds audience. RESULTS: Sixteen persons voluntarily took part in the qualitative study (part A) by participating in one of seven group interview sessions. Of the 14 themes that emerged from these sessions, the most frequent factors motivating attendance involved competent practice and the need to know. All sessions discussed intellectual stimulation, social interaction, time constraints and convenience, licensure, content and format, and absence of cost for attending sessions. The 59 respondents to the survey (part B) identified clinically-useful topics (85%), continuing education credit (46%), cutting-edge research (27%), networking (22%), and refreshments (8%) as motivators and non-relevant topics (44%) and too busy to attend (56%) as barriers. CONCLUSION: Greater understanding of the consumers' perspective can allow planners to tailor the style, content, and logistics to make grand rounds more attractive and inviting

СТРУКТУРНЫЕ ОСОБЕННОСТИ НАНОКОМПОЗИТА FeNi3/C, ПОЛУЧЕННОГО ПРИ ИК–НАГРЕВЕ

The structural features of a nanocomposite FeNi3/C synthesized from a solution FeCl3•6H2O/NiCl2•6H2O/polyacrylonitrile (PAN)/dimethyl formamide (DMF) with CFe=CNi=5; 10; 20; 25 mas. % under an IR heating are studied by a combination scattering (CS), a scanning electron microscopy (SEM), and an X−ray phase analyses (XPA). It is determined that as the IR heating temperature grows from 500 to 700 °С, the FeNi3 nanoparticle size increases from about 15 to 60 nm; amorphous, microcrystalline, and nanocrystalline graphite−like carbon phases (the halo in the XPA spectrum at 2θ ≈ 8÷32°) that are characterized by more intensive band D (ν =1340÷1358 cm−1) than the band G (ν =1560÷1596 cm−1) in the CS spectrum are formed; from the data of a SEM and a CS (the G peak, ν =1596 см−1), the possibility of the graphene structure generation is suggested at 600 and 700  °С; the peak in the area of 1120 cm−1 and the high intensity of the CS spectrum in the region of 1430—1480 cm−1 reveal the formation of polymer−destruction intermediate products at the interface of nanoparticles FeNi3. Методами комбинационного рассеяния света (КРС), сканирующей электронной микроскопии (СЭМ) и рентгенофазового анализа (РФА) исследованы структурные особенности нанокомпозита FeNi3/C, синтезируемого из раствора FeCl3 • 6H2O/NiCl2 •• 6H2O/полиакрилонитрил (ПАН)/диметилформамид (ДМФА) с концентрацией CFe == CNi = 5, 10, 20 и 25 % (масс.) при ИК−нагреве. Установлено, что с ростом температуры ИК−нагрева от 500 до 700 °С размер наночастиц FeNi3 увеличивается приблизительно от 15 до 60 нм; при ИК−нагреве образуются аморфные микрокристаллическая и нанокристаллическая графитоподобные углеродные фазы (гало при 2θ ≈ 8÷32° на спектре РФА), которые характеризуются более интенсивной D−полосой (ν == 1340÷1358 см−1) по сравнению с G−полосой (ν = 1560÷1596 см−1) на спектре КРС; результаты анализа с помощью методов СЭМ и КРС (G−пик, ν = 1596 см−1) нанокомпозитов FeNi3/C свидетельствуют о возможности образования графеновых структур при 600 и 700 °С; пик в области 1120 см−1 и высокая интенсивность спектра КРС в области 1430—1480 см−1указывают на образование промежуточных продуктов деструкции полимера на границе нано-частиц FeNi3

Синтез, структура и электромагнитные свойства нанокомпозитов FeCoCu/C

FeCoCu ternary nanoparticles distributed and stabilized in the carbon matrix of FeCoCu/C metal-carbon nanocomposites have been synthesized using controlled IR pyrolysis of precursors consisting of the “polymer / iron acetylacetate / cobalt and copper acetates” type system obtained by joint dissolution of components followed by solvent removal. The effect of the synthesis temperature on the structure, composition and electromagnetic properties of the nanocomposites has been studied. By XRD was shown that the formation of the FeCoCu ternary nanoparticles occurs due to the interaction of Fe3С with the nanoparticles of the CoCu solid solution. An increase in the synthesis temperature leads to an increase in the size of the metal nanoparticles due to their agglomeration and coalescence as a result of matrix reconstruction. Furthermore, ternary alloy nanoparticles having a variable composition may form depending on the synthesis temperature and the content ratio of the metals. Raman spectroscopy has shown that the crystallinity of the carbon matrix of the nanocomposites increases with the synthesis temperature. The frequency responses of the relative permittivity and permeability of the nanocomposites have been studied at 3–13 GHz. It has been shown that a change in the content ratio of the metals noticeably increases both the dielectric and the magnetic losses. The former loss is caused by the formation of a complex nanostructure of the nanocomposite carbon matrix while the latter one originates from an increase in the size of the nanoparticles and a shift of the natural ferromagnetic resonance frequency to the low-frequency region. The reflection loss has been calculated using a standard method from the experimental data on the frequency responses of the relative permittivity and permeability. It has been shown that the frequency range and the absorption of electromagnetic waves (from –20 to –52 dB) can be controlled by varying the content ratio of the metals in the precursor. The nanocomposites obtained as a result of the experiment deliver better results in comparison with FeCo/C nanocomposites synthesized under similar conditions.Синтезированы тройные наночастицы FeCoCu, распределенные и стабилизированные в углеродной матрице металлоуглеродных нанокомпозитов FeCoCu/C. Синтез нанокомпозитов осуществлен методом контролируемого ИК-пиролиза прекурсоров типа «полимер — ацетилацетонат железа — ацетаты кобальта и меди», полученных совместным растворением компонентов с последующим удалением растворителя. Исследовано влияние температуры синтеза на структуру, состав и электромагнитные свойства нанокомпозитов. Методом рентгенофлуоресцентного анализа показано, что образование тройных наночастиц FeCoCu происходит за счет взаимодействия Fe3С с наночастицами твердого раствора CoCu. С повышением температуры синтеза увеличивается размер наночастиц металлов, что обусловлено процессами их агломерации и коалесценции при перестройке матрицы. Также в зависимости от температуры синтеза и соотношения металлов могут образовываться наночастицы тройного сплава с различным составом. Методом рамановской спектроскопии показано, что с повышением температуры синтеза степень кристалличности углеродной матрицы нанокомпозитов возрастает. Исследованы частотные зависимости относительной комплексной диэлектрической и магнитной проницаемости нанокомпозитов в диапазоне 3—13 ГГц. Показано, что изменение соотношения металлов приводит к значительному увеличению как диэлектрических, так и магнитных потерь. Первые связаны с формированием сложной наноструктуры углеродной матрицы нанокомпозита, а вторые обусловлены увеличением размера наночастиц и сдвигом частоты естественного ферромагнитного резонанса в низкочастотную область. Расчеты потерь на отражение проведены по стандартной методике на основе экспериментальных данных частотных зависимостей комплексной магнитной и диэлектрической проницаемости. Показано, что регулирование частотного диапазона и значения поглощения электромагнитных волн (от –20 до –52 дБ) может осуществляться путем изменения соотношения металлов в прекурсоре. Полученные нанокомпозиты обеспечивают более высокие результаты по сравнению с нанокомпозитами FeCo/C, полученными при аналогичных условиях