Validation of a new blood-mimicking fluid for use in Doppler flow test objects

PM28A is a major intrinsic protein of the spinach leaf plasma membrane and the major phosphoprotein. Phosphorylation of PM28A is dependent in vivo on the apoplastic water potential and in vitro on submicromolar concentrations of Ca2+. Here, we demonstrate that PM28A is an aquaporin and that its water channel activity is regulated by phosphorylation. Wild-type and mutant forms of PM28A, in which putative phosphorylation sites had been knocked out, were expressed in Xenopus oocytes, and the resulting increase in osmotic water permeability was measured in the presence or absence of an inhibitor of protein kinases (K252a) or of an inhibitor of protein phosphatases (okadaic acid). The results indicate that the water channel activity of PM28A is regulated by phosphorylation of two serine residues, Ser-115 in the first cytoplasmic loop and Ser-274 in the C-terminal region. Labeling of spinach leaves with 32P-orthophosphate and subsequent sequencing of PM28A-derived peptides demonstrated that Ser-274 is phosphorylated in vivo, whereas phosphorylation of Ser-115, a residue conserved among all plant plasma membrane aquaporins, could not be demonstrated. This identifies Ser-274 of PM28A as the amino acid residue being phosphorylated in vivo in response to increasing apoplastic water potential and dephosphorylated in response to decreasing water potential. Taken together, our results suggest an active role for PM28A in maintaining cellular water balance.     

Development of a Personal Sampler for Collecting Fungal Spores

Exposure to fungal aerosols is of concern in indoor environments. However, sampling limitations have previously made it difficult to assess exposures accurately, especially long-term exposures. A prototype personal aerosol sampler, based on cyclone principles and using a 1.5 ml microcentrifuge tube as a particle collection receptacle has been designed and fabricated. Collection efficiency for aerosol particles in the size range of fungal spores has been evaluated for different types of microcentrifuge tubes, together with the effect of a polyethylene glycol coating on the inside of the tube and the effect of adding water to the tube. Monodisperse, fluorescently tagged polymer microspheres with median diameters of 0.5, 1, 2, 3, 6, 11, and 16 μm were used to evaluate sampler performance with particle diameter. The microcentrifuge-tube sampler was tested at flow rates of 2 and 4 liters per minute (l/min). Experimental results indicate that the microcentrifuge-tube sampler has an aspiration efficiency of 100% in calm air for particles up to 16 μm. At 4 l/min, the microcentrifuge-tube sampler is able to collect nearly 100% of particles greater than 3 μm and > 90% of particles between 2.5 and 3 μm. The 50% cutoff size is 1.5 μm. The performance of the sampler did not vary with the different brands of tubes tested or with the presence or absence of a coating on the tube surface. Furthermore, the addition of water to the tube resulted in a slight increase in collection efficiency. A sampling time of 5 h was feasible at 45–50% relative humidity before evaporation led to significant water loss.

The cutoff size of 1.5 μm is comparable to many commercially available bioaerosol samplers. Besides being easy to use, simple to fabricate, and inexpensive, this novel sampler has several advantages over conventional samplers: long-term samples are possible (the limitation of impaction methods); there is no sample transfer loss since the transfer step has been eliminated (the limitation of filter cassettes); laboratory analyses are not dependent solely upon a single analysis method (the limitation of impaction methods), and there is no sampler adherence loss (the limitation of trying to wash microorganisms from filters). In addition, use of the sampler would be applicable in a variety of occupational settings from low bioaerosol concentrations (i.e., indoor environments) to high bioaerosol concentrations (i.e., agricultural setting) by varying sampling time periods and using sensitive analytical methods.     

A Numerical Study of the Performance of an Aerosol Sampler with a Curved,Blunt, Multi-Orificed Inlet

The purpose of this study was to numerically simulate the performance of an aerosol sampler with a curved, blunt, multi-orificed inlet in order to understand the sampling characteristics of the first prototype of the button personal inhalable aerosol sampler ("button sampler"). Because the button sampler inlet design is too complicated to apply a three-dimensional model, an axisymmetric two-dimensional model was created to be similar in geometry and to simulate the major features of the airflow through the sampler when facing the wind. Particle trajectories were calculated in a variety of wind velocities and were categorized into 5 groups based on their interactions with the curved surface of the sampling plane. Empirical sampling efficiencies of the button sampler for 3 particle sizes were used to adjust the calculated sampling efficiencies in an attempt to improve the accuracy of the two-dimensional axisymmetric model in accounting for interactions between particles and the surface of the inlet of the button sampler. Sampling efficiencies for other particle sizes were then predicted. The results showed that sampling efficiency decreased with increasing particle size up to approximately 40 w m and then remained virtually unchanged at about 35% up to 100 w m. Although the efficiencies were lower than the American Conference of Governmental Industrial Hygienists' (ACGIH) inhalability curve for larger particles, the pattern of the predicted sampling efficiency was quite similar to the ACGIH inhalability curve. Sampling efficiencies for liquid aerosol particles larger than 15 w m were predicted to be noticeably lower than those for solid particles. The results also showed that the multi-orificed curved surface played an important role in establishing a pressure drop with desired flow alignment inside the sampler, thus greatly reducing the wind effect and significantly improving the uniformity of particle deposition on the filter. The less uniform deposition found at high wind velocity can be improved by increasing the sampling flow rate.     

DK UK10-A系列音箱

UK10-A系列适用于各种固定安装的高档演艺吧、慢摇吧及现场表演。该系列采用高功率扬声器单元和轻巧的箱体搭配,通过计算机优化设计,达到平滑的特性、展宽的频响特点和良好的控制覆盖性能。     

Taxon-specific differences in responsiveness to capsaicin and several analogues: Correlates between chemical structure and behavioral aversiveness

The present set of experiments was designed to explore avian insensitivity to capsaicin. Based upon a molecular model of avian chemosensory repellency, we hypothesized that structural modifications of the basic capsaicin molecule, which is itself not aversive to birds, might produce aversive analogues. To this end, European starlings (Sturnus vulgaris) and Norway rats (Rattus norvegicus) were given varied concentrations of synthetic capsaicin and four analogues (methyl capsaicin, veratryl amine, veratryl acetamide, vanillyl acetamide) in feeding and drinking tests. The results agreed with a model that we are developing to describe the chemical nature of avian repellents. Synthetic capsaicin and vanillyl acetamide were not repellent to birds, owing to the presence of an acidic phenolic OH group. Conversely, veratryl acetamide was aversive, due to the basic nature of this compound. For rats, repellent effectiveness among compounds was reversed: synthetic capsaicin was the best repellent while veratryl acetamide was the worst. We speculate that this taxonomic reversal may reflect basic differences in trigeminal chemoreception. In any case, it is clear that chemical correlates of mammalian repellents are opposite to those that predict avian repellency.     

Arthrogryposis multiplex congenita in an abdominal pregnancy

Dextropropoxyphene hydrochloride increases significantly oxygen uptake in whole rat brain homogenates at concentrations of 10(-4), 10(-5), 10(-6) M when using sucrose 0.25 M pH 7.4 as incubation medium. If substrate and cofactors are added to the sucrose, this drug decreases oxygen uptake at 10(-3) M concentration in brain and liver rat homogenates, and it also decreases significantly the P:O quotient of mitochondria in both organs by uncoupling the oxidative phosphorylation.     

Ophthalmic findings with partial trisomy (duplication) of the long arm of chromosome 7

BACKGROUND: The sensitivity of diagnostic imaging of processes in the parotid gland has been increased by improved spatial resolution, yet specificity remains unchanged. The purpose of this study was to determine whether the low-flow color duplex technique alters the specificity of B-mode ultrasonography. PATIENTS AND METHODS: Forty-one patients with tumors of the parotid gland were examined by color duplex echography as well as histologically. Twenty-eight of the 41 patients had benign tumors and 13 had malignant disease. In 17 of 41 patients, color duplex ultrasonography failed to detect any vascularization within the tumor. Histopathological examination showed that 3 of these 17 tumors were malignant and 14 of 17 were benign. Intranodal vascularization was detected in 24 cases. Ten of these patients were found to have malignant tumors of the parotid gland; 14 had benign parotid tumors. RESULTS: Our present findings show that marked intratumoral vascularization especially appears in malignant tumors. In contrast to lymph nodes, the location and texture of intranodal blood vessels do not provide information about the nature of the neoplasm. CONCLUSIONS: Low flow duplex ultrasonography does not increase the specificity of preoperative examination in tumors of the parotid gland.