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- Integrated bare narrow capillary-hydrodynamic chromatographic system for free-solution DNA separation at the single-molecule level. [Journal Article]
- Angew Chem Int Ed Engl 2013 May 17; 52(21):5612-6.
Turn the volume down: Coupling a high-pressure electroosmotic pump (EOP) and a microfabricated chip-injector with a bare narrow capillary-hydrodynamic chromatographic system (BaNC-HDC), enables samples to be injected at low-picoliter volumes, analytes to be eluted at picoliters per minute, and a wide size range of DNA fragments to be resolved rapidly in free solution at the single-molecule level.
- Microfab-less Microfluidic Capillary Electrophoresis Devices. [JOURNAL ARTICLE]
- Anal Methods 2013 Apr 7; 5(7):1652-1657.
Compared to conventional bench-top instruments, microfluidic devices possess advantageous characteristics including great portability potential, reduced analysis time (minutes), and relatively inexpensive production, putting them on the forefront of modern analytical chemistry. Fabrication of these devices, however, often involves polymeric materials with less-than-ideal surface properties, specific instrumentation, and cumbersome fabrication procedures. In order to overcome such drawbacks, a new hybrid platform is proposed. The platform is centered on the use of 5 interconnecting microfluidic components that serve as the injector or reservoirs. These plastic units are interconnected using standard capillary tubing, enabling in-channel detection by a wide variety of standard techniques, including capacitively-coupled contactless conductivity detection (C(4)D). Due to the minimum impact on the separation efficiency, the plastic microfluidic components used for the experiments discussed herein were fabricated using an inexpensive engraving tool and standard Plexiglas. The presented approach (named 5(2)-platform) offers a previously unseen versatility: enabling the assembly of the platform within minutes using capillary tubing that differs in length, diameter, or material. The advantages of the proposed design are demonstrated by performing the analysis of inorganic cations by capillary electrophoresis on soil samples from the Atacama Desert.
- Lateral transfer, vertical translocation, and survival of inoculated bacteria during moisture enhancement of pork. [Journal Article]
- J Food Prot 2013 Apr; 76(4):595-600.
Lateral transfer, vertical translocation, and survival of bacteria during moisture enhancement of pork were investigated under laboratory conditions. In the first experiment, a pork loin was surface inoculated with Escherichia coli biotype I and moisture enhanced with brine to 10%. After the inoculated loin had been injected, four uninoculated loins were processed in the same manner, without cleaning or sanitizing the injector equipment. Samples were collected from both the surface and the interior tissues of the pork loins. E. coli biotype I was transferred from the inoculated loins to both the exterior and interior of the uninoculated loins in this process. In the second experiment, pork loins were surface inoculated with E. coli biotype I and injected to 10, 20, and 30% of initial weight. After injection, E. coli biotype I was recovered from both the surface and the interior tissues in the pork loins, although there were no significant differences between injection levels. The third experiment was performed to examine the survival of Salmonella enterica Typhimurium and Campylobacter jejuni in recirculating brines. The brine used for injecting pork loins was inoculated with Salmonella Typhimurium or C. jejuni and then recirculated for 48 h at 4 or 10 °C. Samples were collected at specific time intervals, and the surviving populations of the organisms were determined. The populations of both bacteria declined by <1 log over 48 h, and there was no significant difference in populations between temperatures. The present study indicates the potential for cross-contamination of pork during moisture enhancement.
- Stable platinum isotope measurements in presolar nanodiamonds by TEAMS. [JOURNAL ARTICLE]
- Nucl Instrum Methods Phys Res B 2013 Jan; 294(2-2):496-502.
Nanodiamonds are stardust grains commonly found in primitive meteorites. They survived the formation of the solar system and kept their own individuality. Measurements of trace-element isotopic signatures in these grains will help understanding heavy element nucleosynthesis in massive stars and dust formation from their ejecta. We have continued previous attempts to search for stable Pt isotope anomalies in nanodiamonds via trace element accelerator mass spectrometry (TEAMS). The installation of a new injector beam line at the VERA facility allowed studying low traces of stable elements in different materials. Moreover, recent experiments showed that VERA provides the required measurement precision together with a low Pt machine background. Here, we observed for the first time an indication for enhancements of (198)Pt/(195)Pt isotope ratios in two diamond residues prepared by different chemical separation techniques from the Allende meteorite. Variations in other isotopic ratios were within analytical uncertainty, and no anomaly was identified in a third diamond fraction.
- Design and implementation of injector/distributor structures for microfabricated non-porous pillar columns for capillary electrochromatography. [Journal Article]
- J Chromatogr A 2013 May 10.:80-7.
A previously proposed foil definition is applied in the design of injector/distributor structures for solid microfabricated column structures for capillary electrochromatography. In addition to a typical bifurcated distributor, an optimized design alternative with two different configurations is experimentally evaluated. Optimized designs yielded a flat profile for the injected sample with a maximum of 3% variation from the mean width, while it went up to 18% for the typical bifurcated distributor. The implemented electrokinetic injection approach enabled controlling the volume of the injected sample accurately without sacrificing the compactness of the device design. The width of the injected sample was directly proportional to the injection time, namely 165 and 218μm base widths were obtained for 0.6 and 0.8s of feeding, respectively. Reducing the external porosity of the distributor by 85% compared to the typical design, optimized distributors caused a decrease in the mean flow velocity of up to 70%. However, having a flat initial plug shape enabled the separation of a mixture of Coumarin 440, 460, 480 and 540 at 1mm downstream of the injection point in 80s, while it was even not possible to detect the C440 signal for a typical bifurcated design.
- Key elements of space charge compensation on a low energy high intensity beam injector. [Journal Article, Research Support, Non-U.S. Gov't]
- Rev Sci Instrum 2013 Mar; 84(3):033304.
Space charge effect (SCE) along the beam line will decrease beam quality. Space charge compensation (SCC) with extra gas injection is a high-efficiency method to reduce SCE. In this paper, we will report the experimental results on the beam profile, potential distribution, beam emittance, and beam transmission efficiency of a 35 keV∕90 mA H(+) beam and a 40 keV∕10 mA He(+) beam compensated by Ar∕Kr. The influence of gas type, gas flow, and injection location will be discussed. Emphasis is laid on the consideration of SCC when designing and commissioning a high intensity ion beam injector. Based on measured data, a new definition of space charge compensation degree is proposed.
- Effects of a novel push-through technique using the implantable collamer lens injector system for graft delivery during endothelial keratoplasty. [Journal Article]
- Korean J Ophthalmol 2013 Apr; 27(2):87-92.
To investigate effects of a new push-through insertion method for donor lenticules using an injector system on endothelial viability ex vivo and in a clinical case series of endothelial keratoplasty.An ex vivo delivery model was used with porcine corneoscleral rims. We compared the endothelial viability in a new push-through insertion method using the Visian Implantable Collamer Lens (ICL) injector versus that of standard forceps-assisted insertion for lenticule delivery. Twenty porcine corneal lenticules were divided into four groups by insertion method and wound size. Vital dye staining was performed and devitalized areas were semi-quantitatively assessed by digital imaging. In the clinical case series, Descemet's stripping endothelial keratoplasty (DSEK) using the push-through method was performed in seven patients and endothelial outcome was determined six months postoperatively.Mean devitalized areas for the push-through method were significantly lower than for forceps-assisted insertion through 3.2 mm incision (23.99 ± 2.17% vs. 50.48 ± 5.07%, p = 0.009) in the ex vivo model. Average endothelial cell counts of donor tissues of patients who underwent DSEK were 26.4% lower six months postoperatively.Push-through delivery of donor lenticules using the Visian ICL injector system appears to be less harmful to endothelial cells than conventional forceps-assisted delivery.
- Intraocular Lens Delivery Characteristics of the Preloaded AcrySof IQ SN60WS/AcrySert Injectable Lens System. [JOURNAL ARTICLE]
- Am J Ophthalmol 2013 Mar 28.
OBJECTIVE:To evaluate the delivery characteristics of the AcrySof IQ SN60WS intraocular lens (IOL) injected via a preloaded AcrySert delivery system.
DESIGN:Prospective observational case series.
METHODS:setting: This study was carried out in the cataract service of an ophthalmic hospital that serves a large sector of inner-city London. patient population: The study included all patients undergoing routine phacoemulsification procedures with implantation of the SN60WS IOL via the preloaded system over 5 consecutive months. A total of 85 patients (85 eyes) were included in this study. intervention: Phacoemulsification procedures conducted by 7 surgeons were digitally captured. outcome measures: Video recordings of the IOL delivery stage were analyzed by a single observer. Of particular interests were the orientation of the leading haptic and optic on insertion, the degree of intrawound manipulation of the injector, and the time required to satisfactorily deliver the IOL into the capsular bag in a correct orientation. Problems of IOL delivery were also noted.
RESULTS:In 38 out of 85 eyes (45%), correct IOL delivery behavior was achieved with the leading haptic orientating to the left of the surgeon and thus did not require any intrawound rotational manipulation of the injector. Forty-seven of the 85 eyes (55%) required additional rotational manipulation of IOL orientation. Other problems recorded were trapped trailing haptic, haptic-optic adhesion, overriding of the plunger over the optic, and trauma to optic edge. The average time to achieve satisfactory IOL position was 47 seconds. IOL power and the grade of the operating surgeon did not appear to influence the event of a misdirected leading haptic.
CONCLUSIONS:The AcrySof SN60WS/AcrySert system does not appear to meet the expectations of pro-viding a predictable means of IOL delivery.
- Impact of automated contrast injector systems on contrast use and contrast-associated complications in patients undergoing percutaneous coronary interventions. [Journal Article]
- JACC Cardiovasc Interv 2013 Apr; 6(4):399-405.
The purpose of this study was to assess the impact of manual versus automated contrast injection on renal complications in patients undergoing percutaneous coronary intervention (PCI).Contrast volume is a major modifiable risk factor for contrast-induced nephropathy (CIN). Automated contrast injector systems (ACIS) are believed to be associated with a reduction in the total volume of contrast media use.We compared the outcome of 60,884 patients who underwent PCI at 28 hospitals in Michigan in 2008 to 2009 and assessed the outcome of those treated at hospitals that did not use ACIS (n = 24) and compared them with those that used ACIS (n = 4). Propensity matching was used to adjust for baseline differences.The use of ACIS was associated with a statistically significant albeit clinically small difference in the average volume of contrast media use (mean 199 ± 84 ml vs. mean 204 ± 82 ml, p < 0.0001) with no difference in proportion of patients exceeding contrast volume/calculated creatinine clearance ratio of 3 (28.4% vs. 29.1%, p = 0.19). There was no difference in the incidence of CIN (3.11% vs. 3.42%, p = 0.15) or new need for dialysis (0.30% vs. 0.33%, p = 0.54), and these differences remained nonsignificant in propensity matched analysis. In fully adjusted, multivariate logistic analysis, patients treated with ACIS remained as likely to develop CIN (odds ratio: 0.96, 95% confidence interval: 0.83 to 1.11, p = 0.56) or new need for dialysis (odds ratio: 0.83, 95% confidence interval: 0.54 to 1.28, p = 0.40).Compared with hospitals using manual injection, institutions having ACIS used slightly less amount of contrast with no reduction in CIN. Use of ACIS is unlikely to impact contrast-induced renal complications in patients undergoing PCI.
- Endothelial Keratoplasty: Prospective, Randomized, Masked Clinical Trial Comparing an Injector With Forceps for Tissue Insertion. [JOURNAL ARTICLE]
- Am J Ophthalmol 2013 Mar 19.