共查询到20条相似文献,搜索用时 15 毫秒
1.
Huang CW Pei C Huang CH 《Computer methods in biomechanics and biomedical engineering》2011,14(10):915-925
The bolus delivery method is designed to deliver a dose to the desired location in the lung, and it has the advantage of fewer side effects and a more efficient way of delivery. Based upon the lung deposition model developed for continuously inhaling aerosols of constant concentration, a mathematical model of aerosol bolus deposition is proposed. The calculated results show that the recovery depends on the bolus penetration depth, flow rate, particle size, breath holding time and bolus volume. Three sets of published experimental data with different controlling factors (particle size, flow rate and breath holding time) are adopted to make the quantitative comparisons with the calculated results. The predictions and data for the low intrinsic motion particles (~1 μm) have good agreement, as do the coarse particles in the shallow airways region. For females, the recovery was found to be consistently lower than that for males. 相似文献
2.
To understand how to assess optimally the risks of inhaled particles on respiratory health, it is necessary to comprehend the uptake of ultrafine particulate matter by inhalation during the complex transport process through a non-dichotomously bifurcating network of conduit airways. It is evident that the highly toxic ultrafine particles damage the respiratory epithelium in the terminal bronchioles. The wide range of in silico available and the limited realistic model for the extrathoracic region of the lung have improved understanding of the ultrafine particle transport and deposition (TD) in the upper airways. However, comprehensive ultrafine particle TD data for the real and entire lung model are still unavailable in the literature. Therefore, this study is aimed to provide an understanding of the ultrafine particle TD in the terminal bronchioles for the development of future therapeutics. The Euler-Lagrange (E-L) approach and ANSYS fluent (17.2) solver were used to investigate ultrafine particle TD. The physical conditions of sleeping, resting, and light activity were considered in this modelling study. A comprehensive pressure-drop along five selected path lines in different lobes was calculated. The non-linear behaviour of pressure-drops is observed, which could aid the health risk assessment system for patients with respiratory diseases. Numerical results also showed that ultrafine particle-deposition efficiency (DE) in different lobes is different for various physical activities. Moreover, the numerical results showed hot spots in various locations among the different lobes for different flow rates, which could be helpful for targeted therapeutical aerosol transport to terminal bronchioles and the alveolar region. 相似文献
3.
Marzio Zennaro Marco Greco Marina Croci Francesco Caviezel Gisberto Fumagalli 《Aerobiologia》1992,8(1):163-174
Summary The aim of this study is to evaluate the variations of respiratory gas concentration with transcutaneous blood gas measurements (tcm PO2; tcm PCO2) during intermittent positive pressure ventilation (I.P.P.V.) and aerosol therapy in patients (5 female, 5 male; 43–75 years) with chronic obstructive pulmonary diseases (COPD) with haemo gas analysis values PO2<76 mmHg. The subjects underwent transcutaneous blood gas monitoring, 16 minutes during therapy (I.P.P.V. or aerosol) and 14 minutes of recovery. ANOVA analysis of variance was used for statistical analysis. During I.P.P.V. tcm PO2 increase from the base value (60.6±9 mmHg) already after 2 minutes until the 16th minute (69.7±9); 2 minutes after the end of I.P.P.V. tcm PO2 falls below the basic one (57.6±7) and then exceeds the basic value until the 14th minute (63.5±10) (p=ns). The base tcm PCO2 (41.2±7) decreases reaching the maximum decrement at the 16th minute of therapy (32±6.6); at the end of I.P.P.V. it increases without exceeding the base value (39.5±7) (p<0.01). During aerosol therapy, tcm PO2 increases from the basic one (62.4±10) (maximum after 16 minutes 70±9.5), then it decreases (64±11) and increases againg reaching the maximum growth after 14 minutes of recovery (65.7±11) (p=ns). The tcm PCO2 values show a decrement below the base value (42.7±4.5) reaching its maximum at the 16th minute of therapy (38.8±7); at the end of aerosol the tem PCO2 increases (42.5±4.6) (p=ns). The tcm PO2 variations (I.P.P.V. vs aerosol) did not show any significant statistical difference. At the end of the therapies the tcm PO2 falls a little more after I.P.P.V. than after aerosol (57.6±7.3 vs 64±11, p=ns); the tcm PCO2 base values are similar during the two therapies (41.2±7 vs 42.7±4.5, p=ns), but the tcm PCO2 decrements reach a significant statistical difference after 8–10–12–16 minutes (p<0.05); during the recovery time after 2 minutes (34±6.5 vs 40±6.3, p<0.05) and this difference disappeared at the last recording. We calculate the tcm PO2 increment and the tcm PCO2 decrement from the base value. The tcm PO2 increment is higher during I.P.P.V. than during aerosol therapy. The tcm PCO2 decrement shows how the tcm PCO2 falls during I.P.P.V. and how these values remain below the base one until the end of the rest time. Data reported here demonstrate that mechanical physiokinesi therapy improves COPD ventilation so that the respiratory pattern could be ameliorated and preserved. 相似文献
4.
5.
Christopher N Mills Chantal Darquenne G Kim Prisk 《Journal of applied physiology》2002,92(3):1232-1238
We studied the effects on aerosol bolus inhalations of small changes in convective inhomogeneity induced by posture change from upright to supine in nine normal subjects. Vital capacity single-breath nitrogen washout tests were used to determine ventilatory inhomogeneity change between postures. Relative to upright, supine phase III slope was increased 33 +/- 11% (mean +/- SE, P < 0.05) and phase IV height increased 25 +/- 11% (P < 0.05), consistent with an increase in convective inhomogeneity likely due to increases in flow sequencing. Subjects also performed 0.5-microm-particle bolus inhalations to penetration volumes (V(p)) between 150 and 1,200 ml during a standardized inhalation from residual volume to 1 liter above upright functional residual capacity. Mode shift (MS) in supine posture was more mouthward than upright at all V(p), changing by 11.6 ml at V(p) = 150 ml (P < 0.05) and 38.4 ml at V(p) = 1,200 ml (P < 0.05). MS and phase III slope changes correlated positively at deeper V(p). Deposition did not change at any V(p), suggesting that deposition did not cause the MS change. We propose that the MS change results from increased sequencing in supine vs. upright posture. 相似文献
6.
I. D. Kolesin 《Biophysics》2007,52(1):92-94
A model of a pathogenic system with respiratory transmission was proposed. The internal regulation mechanism and the conditions for the onset of seasonal rise in morbidity were studied. The role of asymptomatic carriers in the formation of the virulence potential of the pathogen was shown. 相似文献
7.
Gas-phase reactors, including the mist reactor, have distinct advantages over liquid-phase reactors including the ability to manipulate the gas composition, to allow effective gas exchange in a densely growing biomass, and to affect secondary metabolite production. Mathematical modeling suggested that roots in a mist reactor are often too sparsely packed to capture mist particles efficiently and cannot, therefore, meet the nutrient demands required to maintain high growth rates. Indeed, growth rates of Artemisia annua hairy roots increased significantly when the initial packing density increased or when a higher sucrose concentration was used in the medium. Growth kinetics for 2, 4, and 6 days, however, showed a decrease or stationary growth rate after only 4 days for both 3 and 5% sucrose feeds. Residual medium analyses indicated that carbon was not exhausted, nor were any of the other major nutrients including phosphate. Increasing the mist duty cycle at constant carbon flux through the reactor reduced the growth rates slightly. In general, the aerosol deposition model correctly predicted how to optimize hairy root growth in the mist reactor. 相似文献
8.
9.
研究了普通齿蛉Neoneuromus ignobilis Navás幼虫的呼吸系统及其呼吸行为。结果表明:普通齿蛉幼虫为全气门式(10对气门)呼吸系统,前中胸、中后胸之间、腹部8节各有1对气门,腹部8节各有气管鳃1对,前6对细短,管状,有较短绒毛,后2对气管鳃较粗长,呈羽毛状。腹部1~7节各有1对毛簇,第8腹节无毛簇。侧纵干气管较粗,4束,自前胸前缘部分成左右2组,每组两根侧纵干气管,向胸腹部延伸,二级气管分别伸达各个气门和毛簇,腹部每节由毛簇处的二级气管分支而来的三级气管相连或延伸至消化道等处。气管鳃中无气管。有毛簇呼吸、气门呼吸和体壁呼吸3种呼吸方式,在水中以毛簇呼吸为主,在陆上进行气门呼吸和体壁呼吸。 相似文献
10.
The toxicity of dung from cattle treated with an ivermectin sustained-release bolus was estimated in terms of ivermectin or ivermectin equivalents, using a laboratory bioassay with the dung fly Neomyia cornicina Fabricius (Diptera, Muscidae). The mortalities of flies measured 7 days after feeding for 24 h on dung containing known concentrations of ivermectin (between 0.125 and 1 g ivermectin per gram fresh dung) were compared with the mortalities of insects fed for 24 h on dung from cattle treated 21 days previously with an ivermectin sustained-release bolus. The toxicity of the bolus dung was equivalent to dung containing 0.66 g ivermectin per gram fresh dung. To determine whether insects could differentiate between control dung and dung from bolus-treated cattle, choice-chamber tests were carried out. There was no significant difference in the percentage of females that chose either dung type, suggesting that they were unable to distinguish the dung of bolus-treated cattle from control dung. Results are discussed in relation to the impact that bolus use can have on the insect fauna of cattle dung. 相似文献
11.
12.
13.
14.
Antitumor efficacy and intratumoral distribution of SN-38 from polymeric depots in brain tumor model
Ketpat Vejjasilpa Norased Nasongkla Chawan Manaspon Noppadol Larbcharoensub Atthaporn Boongird Suradej Hongeng Nipan Israsena 《Experimental biology and medicine (Maywood, N.J.)》2015,240(12):1640-1647
We investigate antitumor efficacy and 2D and 3D intratumoral distribution of 7-ethyl-10-hydroxycamptothecin (SN-38) from polymeric depots inside U-87MG xenograft tumor model in nude mice. Results showed that polymeric depots could be used to administer and controlled release of a large amount of SN-38 directly to the brain tumor model. SN-38 released from depots suppressed tumor growth, where the extent of suppression greatly depended on doses and the number of depot injections. Tumor suppression of SN-38 from depots was three-fold higher in animals which received double injections of depots at high dose (9.7 mg of SN-38) compared to single injection (2.2 mg). H&E staining of tumor sections showed that the area of tumor cell death/survival of the former group was two-fold higher than those of the latter group. Fluorescence imaging based on self-fluorescent property of SN-38 was used to evaluate the intratumoral distribution of this drug compared to histological results. The linear correlation between fluorescence intensity and the amount of SN-38 allowed quantitative determination of SN-38 in tumor tissues. Results clearly showed direct correlation between the amount of SN-38 in tumor sections and cancer cell death. Moreover, 3D reconstruction representing the distribution of SN-38 in tumors was obtained. Results from this study suggest the rationale for intratumoral drug administration and release of drugs inside tumor, which is necessary to design drug delivery systems with efficient antitumor activity. 相似文献
15.
藏东南大气氮湿沉降动态变化——以林芝观测点为例 总被引:12,自引:2,他引:12
利用量雨器和湿沉降收集仪在藏东南通过2a的试验, 研究了该区大气氮素沉降的浓度、沉降量以及季节变化规律.结果表明:藏东南大气氮素湿沉降(无机氮)为1.33~3.05 kg/ (hm2·a),平均值为2.36 kg/ (hm2·a),降水中铵态氮和硝态氮的平均浓度分别为0.36 mg/L和0.10 mg/L ,NH+4-N/ NO-3-N接近4 .各形态氮月均浓度之间差别较大,具有明显的季节性,其中NH+4-N月均浓度动态变化明显,5、6、7月份浓度较高(>0.5 mg/L),NO-3-N 12月份浓度(0.49 mg/L)为全年最高;氮浓度的季节变化,以春冬较高,夏秋季较低,离散程度以春季最大.降水量与各形态氮沉降呈一定幂型负相关,相关系数为0.705,0.641,分别达到0.006 (NH+4-N)和0.019(NO-3-N)的显著水平.氮月沉降以5~6月份最高,占全年的32.3%;氮季沉降以夏季所占比例最高,约占50%,冬季最低(2%~3%). 相似文献
16.
Therapeutic effect of intra‐articular injection of ribbon‐type decoy oligonucleotides for hypoxia inducible factor‐1 on joint contracture in an immobilized knee animal model 下载免费PDF全文
Daisuke Sotobayashi Hirohisa Kawahata Natsuki Anada Toshio Ogihara Ryuichi Morishita Motokuni Aoki 《The journal of gene medicine》2016,18(8):180-192
17.
P. Perrott G. Smith Z. Ristovski R. Harding M. Hargreaves 《Journal of applied microbiology》2009,106(5):1438-1447
Aims: Influenza is commonly spread by infectious aerosols; however, detection of viruses in aerosols is not sensitive enough to confirm the characteristics of virus aerosols. The aim of this study was to develop an assay for respiratory viruses sufficiently sensitive to be used in epidemiological studies.
Method: A two-step, nested real-time PCR assay was developed for MS2 bacteriophage, and for influenza A and B, parainfluenza 1 and human respiratory syncytial virus. Outer primer pairs were designed to nest each existing real-time PCR assay. The sensitivities of the nested real-time PCR assays were compared to those of existing real-time PCR assays. Both assays were applied in an aerosol study to compare their detection limits in air samples.
Conclusions: The nested real-time PCR assays were found to be several logs more sensitive than the real-time PCR assays, with lower levels of virus detected at lower Ct values. The nested real-time PCR assay successfully detected MS2 in air samples, whereas the real-time assay did not.
Significance and Impact of the Study: The sensitive assays for respiratory viruses will permit further research using air samples from naturally generated virus aerosols. This will inform current knowledge regarding the risks associated with the spread of viruses through aerosol transmission. 相似文献
Method: A two-step, nested real-time PCR assay was developed for MS2 bacteriophage, and for influenza A and B, parainfluenza 1 and human respiratory syncytial virus. Outer primer pairs were designed to nest each existing real-time PCR assay. The sensitivities of the nested real-time PCR assays were compared to those of existing real-time PCR assays. Both assays were applied in an aerosol study to compare their detection limits in air samples.
Conclusions: The nested real-time PCR assays were found to be several logs more sensitive than the real-time PCR assays, with lower levels of virus detected at lower Ct values. The nested real-time PCR assay successfully detected MS2 in air samples, whereas the real-time assay did not.
Significance and Impact of the Study: The sensitive assays for respiratory viruses will permit further research using air samples from naturally generated virus aerosols. This will inform current knowledge regarding the risks associated with the spread of viruses through aerosol transmission. 相似文献
18.
Mukunda Phuyal Rebekka R. E. Artz Lucy Sheppard Ian D. Leith David Johnson 《Plant Ecology》2008,196(1):111-121
Here we investigate the effect of 4 years simulated atmospheric deposition of ammonium (NH4) and nitrate (NO3), applied alone or in combination with phosphorus and potassium (PK), on the surface phosphatase activities and nutrient
acquisition behaviour of two species of moss (Sphagnum
capillifolium and Hypnum jutlandicum) from an ombrotrophic peatland. Phosphatase activity was significantly enhanced by both the NH4 and NO3 treatments, particularly for Sphagnum, but the activity decreased when exposed to additions of PK. Regression analysis revealed that phosphatase activity on Sphagnum was positively related with tissue N and negatively related to tissue P concentrations. For Hypnum, a negative relationship between shoot P concentration and phosphatase activity was observed. Using a 32P tracer, mosses removed from plots receiving PK in combination with NH4 maintained their affinity for increased phosphorus uptake. These findings suggest that enhanced nutrient supply, even at
modest doses, significantly alter the nutrient recycling behaviour of bryophytes. 相似文献
19.
儿童下呼吸道感染的金黄色葡萄球菌耐药性分析 总被引:4,自引:0,他引:4
对 4 2 38例下呼吸道感染患儿深部痰液标本中的金黄色葡萄球菌进行分离培养 ,并用细菌自动分析系统Vitek 6 0进行菌种鉴定和药物敏感试验。金黄色葡萄球菌分离阳性率为 2 .1% (89/ 4 2 38)。所分离的89株金黄色葡萄球菌中 ,95 .5 % (85 / 89)菌株产 β 内酰胺酶 ;但仅 4 .5 % (4 / 89)菌株耐苯唑西林 (MRSA) ,其中 3株显示多重耐药。 96 .6 %和 4 8.3%的菌株分别对青霉素和红霉素耐药 ,14 .6 %~ 2 5 .9%分别对四环素、林可霉素、复方新诺明耐药 ;对其余临床常用抗生素 ,如庆大霉素、苯唑西林、氨苄西林 /舒巴坦、阿莫西林 /克拉维酸、头孢唑啉、环丙沙星、左氧氟沙星等的耐药率均低于 10 %。上述实验结果提示 ,本地区引起患儿下呼吸道感染的金黄色葡萄球菌对多数临床常用抗生素仍敏感 ,β 内酰胺酶阳性菌株极为普遍 ,但MRSA所占比例不高。 相似文献
20.
《Bioscience, biotechnology, and biochemistry》2013,77(9):2242-2247
To develop a new drug delivery system, antibacterial 50–900 nm nanoparticles of shell and internal organs from scallops collected off Huksan-Island, Korea, were prepared by dry grind technology respectively. The diameters, identities, and conformations of the scallop shell and internal organ particles were determined with a particle-size analyzer and by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and Raman spectroscopy. The antibacterial properties of the nanoparticles from scallop shell were investigated in the absence and the presence of scallop-shell extract. Bacterial growth was reduced with the supernatant of the nanoparticle scallop-shell extract. Also, the nanoparticles from scallop shell were much more effective as a skin softener than was powder. These facts provide us with guidelines for the study of the size-dependent properties of functional materials as well as for further applications to drug delivery systems (DDSs) and cosmetic raw materials. 相似文献