83 research outputs found
Portable Microfluidic Integrated Plasmonic Platform for Pathogen Detection
Timely detection of infectious agents is critical in early diagnosis and treatment of infectious diseases. Conventional pathogen detection methods, such as enzyme linked immunosorbent assay (ELISA), culturing or polymerase chain reaction (PCR) require long assay times, and complex and expensive instruments, which are not adaptable to point-of-care (POC) needs at resource-constrained as well as primary care settings. Therefore, there is an unmet need to develop simple, rapid, and accurate methods for detection of pathogens at the POC. Here, we present a portable, multiplex, inexpensive microfluidic-integrated surface plasmon resonance (SPR) platform that detects and quantifies bacteria, i.e., Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) rapidly. The platform presented reliable capture and detection of E. coli at concentrations ranging from ∼105 to 3.2 × 107 CFUs/mL in phosphate buffered saline (PBS) and peritoneal dialysis (PD) fluid. The multiplexing and specificity capability of the platform was also tested with S. aureus samples. The presented platform technology could potentially be applicable to capture and detect other pathogens at the POC and primary care settings. © 2015, Nature Publishing Group. All rights reserved
Ultrafast laser micro-nano structuring of transparent materials with high aspect ratio
Ultrafast lasers are ideal tools to process transparent materials because
they spatially confine the deposition of laser energy within the material's
bulk via nonlinear photoionization processes. Nonlinear propagation and
filamentation were initially regarded as deleterious effects. But in the last
decade, they turned out to be benefits to control energy deposition over long
distances. These effects create very high aspect ratio structures which have
found a number of important applications, particularly for glass separation
with non-ablative techniques. This chapter reviews the developments of
in-volume ultrafast laser processing of transparent materials. We discuss the
basic physics of the processes, characterization means, filamentation of
Gaussian and Bessel beams and provide an overview of present applications
Therapeutic and diagnostic efficacy of adenosine in childhood tachycardia
Adenosine is an endogenous nucleoside that has been used in the diagnosis and treatment of tachycardias, including those with normal QRS durations and those with wide QRS complexes in both children and adults. The electrophysiologic basis for the use of adenosine is primarily its depressant effect on conduction in the atrioventricular node and its antiadrenergic effect an the ventricular myocardium. In our study, adenosine was administered intravenously via bolus dose to 43 patients with supraventricular and ventricular tachycardias as well as ventricular extrasystoles. Adenosine successfully terminated 11 of 12 tachycardias using the atrioventricular node as reentrant circuit. It induced transient complete atrioventricular nodal block, unmasking the typical appearance of the flutter and fibrillation waves on the surface electrogram. It was also useful in terminating and therefore diagnostic in ventricular ectopic activity in two patients and ventricular tachycardias in five patients, suggesting that the mechanism is triggered activity. Adenosine's rapid metabolism ensures that a bolus injection is rapidly removed from the circulation; consequently no serious side effects were seen in our study
Posterior deviation of left ventricular outflow tract septal components without ventricular septal defect.
OBJECTIVE: To describe 11 patients with narrowing of the left ventricular outflow tract caused by angular posterior deviation of both the outlet septum and the upper part of trabecular septum, which was diagnosed by cross sectional echocardiography in all and confirmed by angiocardiography in seven. RESULTS: Four patients had a subaortic systolic pressure gradient ranging from 23 to 70 mm Hg by Doppler echocardiography; cardiac catheterisation showed a significant (60 and 104 mm Hg) systolic pressure gradient in two. In four cases aortic regurgitation and two tricuspid pouches were shown by Doppler echocardiography, angiocardiography, or both. Four cases had a ridge at the angulation point on echocardiographic examination. Three patients were operated on for systolic pressure gradients of the left ventricular outflow tract and one for severe aortic regurgitation. There was proliferation of collagen-rich fibrous tissue in the subendocardial region on histopathological examination of the myectomy material. A ventricular septal defect had been diagnosed previously by contrast echocardiography in one patient; thus ventricular septal defects may close spontaneously over a period of time including fetal life. A subaortic ridge was detected in one patient at follow up. CONCLUSIONS: Deviation of the outlet and trabecular septa should be considered as a cause of ventricular outflow tract obstruction even when no ventricular septal defect is present
Photodissociation of Ozone from 321 to 329 nm: The Relative Yields of O(<sup>3</sup>P<sub>2</sub>) with O<sub>2</sub>(<i>X</i> <sup>3</sup>Σ<sub>g</sub><sup>–</sup>), O<sub>2</sub>(<i>a</i> <sup>1</sup>Δ<sub>g</sub>) and O<sub>2</sub>(<i>b</i> <sup>1</sup>Σ<sub>g</sub><sup>+</sup>)
Product imaging of
O(<sup>3</sup>P<sub>2</sub>) following dissociation
of ozone has been used to determine the relative yields of the product
channels O(<sup>3</sup>P<sub>2</sub>) + O<sub>2</sub>(<i>X</i> <sup>3</sup>Σ<sub>g</sub><sup>–</sup>) of ozone. All
three channels are prominent at all wavelengths investigated. O<sub>2</sub> vibrational distributions for each channel and each wavelength
are also estimated assuming Boltzmann rotational distributions. Averaged
over wavelength in the measured range, the yields of the O(<sup>3</sup>P<sub>2</sub>) + O<sub>2</sub>(<i>X</i> <sup>3</sup>Σ<sub>g</sub><sup>–</sup>), O(<sup>3</sup>P<sub>2</sub>) + O<sub>2</sub>(<i>a</i> <sup>1</sup>Δ<sub>g</sub>), and
O(<sup>3</sup>P<sub>2</sub>) + O<sub>2</sub>(<i>b</i> <sup>1</sup>Σ<sub>g</sub><sup>+</sup>) channels are 0.36, 0.31,and
0.34, respectively. Photofragment distributions in the spin-allowed
channel O(<sup>3</sup>P) + O<sub>2</sub>(<i>X</i> <sup>3</sup>Σ<sub>g</sub><sup>–</sup>) are compared with the results
of quantum mechanical calculations on the vibronically coupled PESs
of the singlet states B (optically bright) and R (repulsive). The
experiments suggest that considerably more vibrational excitation
and less rotational excitation occur than predicted by the quantum
calculations. The rotational distributions, adjusted to fit the experimental
images, suggest that the dissociation takes place from a more linear
configuration than the Franck–Condon bending angle of 117°.
The dissociation at most wavelengths results in a positive value of
the anisotropy parameter, β, both in the experiment and in the
calculations. Calculations indicate that both nonadiabatic transitions
and intersystem crossings substantially reduce β below the nominal
value of 2
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