1,122 research outputs found
A Microcantilever-based Gas Flow Sensor for Flow Rate and Direction Detection
The purpose of this paper is to apply characteristics of residual stress that
causes cantilever beams to bend for manufacturing a micro-structured gas flow
sensor. This study uses a silicon wafer deposited silicon nitride layers,
reassembled the gas flow sensor with four cantilever beams that perpendicular
to each other and manufactured piezoresistive structure on each
micro-cantilever by MEMS technologies, respectively. When the cantilever beams
are formed after etching the silicon wafer, it bends up a little due to the
released residual stress induced in the previous fabrication process. As air
flows through the sensor upstream and downstream beam deformation was made,
thus the airflow direction can be determined through comparing the resistance
variation between different cantilever beams. The flow rate can also be
measured by calculating the total resistance variations on the four
cantilevers.Comment: Submitted on behalf of EDA Publishing Association
(http://irevues.inist.fr/handle/2042/16838
Bacteremic pneumonia caused by extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae: Appropriateness of empirical treatment matters
BackgroundClinical information about bacteremic pneumonia caused by extended-spectrum beta-lactamase (ESBL)-producing organism is limited.MethodsA retrospective study was conducted at two medical centers in Taiwan. From May 2002 to August 2010, clinical information and outcome of adults with bacteremic pneumonia caused by ESBL-producing Escherichia coli and Klebsiella pneumoniae were analyzed. The primary outcome is the 30-day mortality.ResultsA total of 111 patients with bacteremic pneumonia caused by E. coli (37 patients, 33.3%) and K. pneumoniae (74, 66.7%) were identified. Their mean age was 69.2 years and 51.4% were male patients. Fifty-seven (51.3%) episodes were classified as hospital-acquired infections, 19 (17.1%) as health-care-associated infections, and four (3.6%) as community-acquired infections. Fifty-one (45.9%) patients received appropriate empiric antimicrobial therapy. The 30-day mortality rate was 40.5% (45 patients). In the multivariate analysis, several independent risk factors, including rapidly fatal underlying disease [odds ratio (OR), 5.75; 95% confidence interval (CI), 1.54â21.48; p = 0.009], severe sepsis (OR, 4.84; 95% CI, 1.55â15.14; p = 0.007), critical illness (OR, 4.28; 95% CI, 1.35â13.57; p = 0.013), and receipt of appropriate empirical therapy (OR, 0.19; 95% CI, 0.07â0.55; p = 0.002), were associated with 30-day mortality. The survival analysis consistently found that individuals with appropriate empiric therapy had a higher survival rate (log-rank test, p < 0.001).ConclusionESBL-producing bacteremic pneumonia, especially health-care-associated infections, often occurred in adults with comorbidities. Appropriate empirical therapy was associated with a favorable outcome
Prevalence of Pediculus Capitis Infestation Among School Children of Chinese Refugees Residing in Mountainous Areas of Northern Thailand
An epidemiologic survey of Pediculus capitis infestation among Akka aboriginal and Han children of Chinese refugees living in mountainous areas at elevations of 1,100 to 1,400 m in Chiang-Rai Province of northern Thailand was conducted during January 2003. Of the 303 children examined, 43 (14.2%) had P. capitis infestation. The overall infestation rate for P. capitis in Akka children (29.3%, 12/41) was significantly higher than that in Han children (11.8%, 31/262; c2 = 8.161, p = 0.002). The prevalence in Akka (52.2%, 12/23) and Han girls (19.7%, 31/157) was higher than that in Akka (0%) and Han boys (0%), respectively (p < 0.001), and the prevalence was higher in Akka girls than in Han girls (c2 = 10.978, p = 0.001). The high prevalence of P. capitis infestation among these girls was possibly due to poor environmental hygiene and unavailability of sufficient water
Aciculatin inhibits lipopolysaccharide-mediated inducible nitric oxide synthase and cyclooxygenase-2 expression via suppressing NF-ÎșB and JNK/p38 MAPK activation pathways
<p>Abstract</p> <p>Objectives</p> <p>Natural products have played a significant role in drug discovery and development. Inflammatory mediators such as inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) have been suggested to connect with various inflammatory diseases. In this study, we explored the anti-inflammatory potential of aciculatin (8-((2<it>R</it>,4<it>S</it>,5<it>S</it>,6<it>R</it>)-tetrahydro-4,5-dihydroxy-6-methyl-2<it>H</it>-pyran-2-yl)-5-hydroxy-2-(4-hydroxyphenyl)-7-methoxy-4<it>H</it>-chromen-4-one), one of main components of <it>Chrysopogon aciculatis</it>, by examining its effects on the expression and activity of iNOS and COX-2 in lipopolysaccharide (LPS)-activated macrophages.</p> <p>Methods</p> <p>We used nitrate and prostaglandin E<sub>2 </sub>(PGE<sub>2</sub>) assays to examine inhibitory effect of aciculatin on nitric oxide (NO) and PGE<sub>2 </sub>levels in LPS-activated mouse RAW264.7 macrophages and further investigated the mechanisms of aciculatin suppressed LPS-mediated iNOS/COX-2 expression by western blot, RT-PCR, reporter gene assay and confocal microscope analysis.</p> <p>Results</p> <p>Aciculatin remarkably decreased the LPS (1 ÎŒg/mL)-induced mRNA and protein expression of iNOS and COX-2 as well as their downstream products, NO and PGE<sub>2 </sub>respectively, in a concentration-dependent manner (1-10 ÎŒM). Such inhibition was found, via immunoblot analyses, reporter gene assays, and confocal microscope observations that aciculatin not only acts through significant suppression of LPS-induced NF-ÎșB activation, an effect highly correlated with its inhibitory effect on LPS-induced IÎșB kinase (IKK) activation, IÎșB degradation, NF-ÎșB phosphorylation, nuclear translocation and binding of NF-ÎșB to the ÎșB motif of the iNOS and COX-2 promoters, but also suppressed phosphorylation of JNK/p38 mitogen-activated protein kinases (MAPKs).</p> <p>Conclusion</p> <p>Our results demonstrated that aciculatin exerts potent anti-inflammatory activity through its dual inhibitory effects on iNOS and COX-2 by regulating NF-ÎșB and JNK/p38 MAPK pathways.</p
Focal Stenosis in Right Upper Lobe Bronchus in a Recurrently Wheezing Child Sequentially Studied by Multidetector-row Spiral Computed Tomography and Scintigraphy
Lower respiratory tract infections associated with wheezing are not uncommon in infants and young children. Among the wheezing-associated disorders, allergic etiologies are more commonly encountered than anatomic anomalies. We present a 3-year-old girl with a sudden attack of asthmatic symptoms including dyspnea, cyanosis and diffuse wheezing. Based on a history of choking, and atelectasis in the right upper lobe detected by chest films, flexible tracheobronchoscopy was arranged and incidentally detected a stenotic orifice in the right upper lobe bronchus. Multidetector-row spiral computed tomography and pulmonary scintigraphy subsequently also disclosed the focal stenosis. She suffered from recurrent wheezing, pneumonia and lung atelectasis during 1 year of follow-up. We emphasize the diagnosis, clinical course and management of focal stenosis in the right upper lobe bronchus
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