The effect of temperature and electrical drive conditions on the output of lead zirconate titanate (PZT) transducers is of particular interest in ultrasound metrology and medical ultrasound ...applications. In this work, the temperature-dependent output of two single-element PZT transducers was measured between 22 °C and 46 °C. Two independent measurement methods were used, namely radiation force balance measurements and laser vibrometry. When driven at constant voltage using a 50 Ω matched signal generator and amplifier using continuous wave (CW) or quasi-CW excitation, the output of the two transducers increased on average by 0.6 % per degree, largely due to an increase in transducer efficiency with temperature. The two measurement methods showed close agreement. Similar trends were observed when using single cycle excitation with the same signal chain. However, when driven using a pulser (which is not electrically matched), the two transducers exhibited different behaviour depending on their electrical impedance. Accounting for the temperature-dependent output of PZT transducers could have implications for many areas of ultrasound metrology, for example, in therapeutic ultrasound where a coupling fluid at an increased or decreased temperature is often used.
•Output of most lead zirconate titanate (PZT) transducers changes with temperature.•Transducer efficiency increases with temperature.•Temperature dependence of transducer output depends on electrical drive system.•Radiation force balances and laser vibrometry can measure the transducer output.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The microextraction sampling technique was integrated with triple quadrupoleinductively coupled plasma–mass spectrometry (TQ–ICP–MS) to directly sample and measure the isotopic compositions of ...uranium (U) and plutonium (Pu) from cotton swipes. Once extracted, the U/Pu were directed into the TQ–ICP–MS instrument for isotopic determination. Carbon dioxide (CO2) and helium (He) gases were delivered to a collision reaction cell within the ICP–MS system for ion separation. The CO2 reacts with the U+ forming UO+ which is ultimately separated from the Pu+ ions of interest in the third quadrupole. This study demonstrates direct liquid extraction of U/Pu from a solid surface and subsequent measurement by TQ–ICP–MS in <60 s. Flow rates were optimized (0.3 mL min–1 CO2 and 5 mL min–1 He) in the reaction cell of the ICP–MS system to maximize the Pu signal while minimizing U interferences (i.e., 238U+ tail and 238UH+) at m/z 239. Low levels of Pu (∼2 pg) were deposited on a cotton swipe along with U at concentrations ranging from 20 to 200 ng. The 240Pu/239Pu ratio was measured with <7% relative difference from the certified value at all U concentrations. Major and minor U isotope ratios were also measured with <4% relative difference. This highlights that the microextraction–TQ–ICP–MS method can extract a mixed U/Pu sample directly from a cotton swipe and measure both isotopic systems without chemical separation.
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Lassa fever is a severe multisystem disease that often has haemorrhagic manifestations. The epitopes of the Lassa virus (LASV) surface glycoproteins recognized by naturally infected human hosts have ...not been identified or characterized. Here we have cloned 113 human monoclonal antibodies (mAbs) specific for LASV glycoproteins from memory B cells of Lassa fever survivors from West Africa. One-half bind the GP2 fusion subunit, one-fourth recognize the GP1 receptor-binding subunit and the remaining fourth are specific for the assembled glycoprotein complex, requiring both GP1 and GP2 subunits for recognition. Notably, of the 16 mAbs that neutralize LASV, 13 require the assembled glycoprotein complex for binding, while the remaining 3 require GP1 only. Compared with non-neutralizing mAbs, neutralizing mAbs have higher binding affinities and greater divergence from germline progenitors. Some mAbs potently neutralize all four LASV lineages. These insights from LASV human mAb characterization will guide strategies for immunotherapeutic development and vaccine design.
Business analytics is driving the way organizations compete. However, the decisions made as a result of any analytics process are greatly dependent on the quality of the data from which they are ...based. Scholars suggest several data quality improvement methods, and commercial software is now available that can help improve data quality. Although organizations are motivated to find ways to improve analytic capabilities and using these methods has been shown to improve some measures of data quality, there is little understanding of the tangible and intangible outcomes of employing these methods. In this study, we explore outcomes that arise from a data quality improvement process implementation in an operations management environment. Over a three-year period, we conducted a longitudinal single case study at an organization that maintains a large fleet of aircraft, collecting and analyzing qualitative interviews and observations. The findings suggest outcomes (both positive and cautionary) associated with the implementation of data quality improvement processes. These include increased stakeholder commitment to data quality and business analytics, as well as an over-emphasis on program metrics to the peril of operational outcomes, among others. From the basis of our findings, we construct a research agenda, which includes testable Propositions regarding outcomes of data quality improvement.
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A microextraction liquid sampling system coupled to a quadrupole inductively coupled plasma-mass spectrometer (ICP-MS) was utilized to spatially discern uranium particles, isotopically, on a ...cellulose-based swipe material (
i.e.
, J-type swipe). These types of swipes are often used by the International Atomic Energy Agency (IAEA) as part of their environmental sampling program. A grid was created such that extraction locations covered the center circle (
n
= 34 without overlapping). Uranium (U) particulates (<20 μm) of varying U isotopic abundance and chemical form (
i.e.
, uranyl fluoride and uranyl nitrate hexahydrate) were mechanically placed on the swipes in random locations and detected
via
the microextraction-ICP-MS methodology. Heat maps were subsequently generated to show the placement of the particulate with their respective intensity and isotopic determination. This detection of the uranium particulates,
via
isotopic determination, agreed with reference values for these materials. Additionally, depleted (
235
U/
238
U = 0.002) uranium particulates were placed directly within a clay matrix, on the swipe surface, and subjected to analysis by microextraction-ICP-MS. The mapping of the swipe demonstrated, for the first time, the employment of the microextraction-ICP-MS method for extracting sample from a complex matrix, and correctly identifying the uranium isotopic composition. This example ultimately demonstrates the utility of the methodology for detecting particles of interest in complex matrices.
A microextraction sampling system coupled to a quadrupole inductively coupled plasma-mass spectrometer (ICP-MS) was utilized to spatially discern uranium particles, isotopically, on a cellulose-based swipe material (
i.e.
, J-type swipe).
This study sought to identify concurrent major comorbidities in preterm infants ≤32 weeks of gestation that may have contributed to sepsis-related mortality following a diagnosis of bacteremia or ...blood culture-negative sepsis within the neonatal period (≤28 days of life).
This is a retrospective chart review of infants ≤32 weeks of gestation who were admitted to a single academic network of multiple neonatal intensive care units between January 1, 2012, and December 31, 2015, to determine the primary cause(s) and timing of death in those diagnosed with bacteremia or blood culture-negative sepsis. Direct comparisons between early-onset sepsis (EOS; ≤72 hours) and late-onset sepsis (LOS; >72 hours) were made.
In our study cohort, of 939 total patients with ≤32 weeks of gestation, 182 infants were diagnosed with 198 episodes of sepsis and 7.7% (14/182) died. Mortality rates did not significantly differ between neonates with bacteremia or blood culture-negative sepsis (7/14 each group), and those diagnosed with EOS compared with LOS (6/14 vs. 8/14). Nearly 80% (11/14) of infants were transitioned to comfort care prior to their death secondary to a coinciding diagnosis of severe grade-3 or -4 intraventricular hemorrhage, periventricular leukomalacia, necrotizing enterocolitis, and/or intestinal perforation.
Preexisting comorbidities commonly associated with extreme preterm birth contributed to sepsis-related mortality in our patient cohort.
· Concurrent comorbidities contribute to, and may artificially inflate, sepsis-related mortality.. · Absence of a consensus definition for neonatal sepsis complicates the investigation of infection.. · Accurate assessment of the incidence of sepsis in very low birth weight infants is vital for future investigations..
The determination of trace elements, particularly rare earth elements, in uranium ore concentrates (UOCs) is important as the pattern can be indictive ore characteristics. Presented here is a ...methodology for accurately quantifying rare earth elements (REE) in UOCs. To improve the measurement uncertainty, isotope dilution mass spectrometry (IDMS) was utilized over other quantification techniques such as external calibration or standard addition. The isotopic determinations were measured by inductively coupled plasma-mass spectrometry (ICP-MS). To obtain high-fidelity isotopic measurements, separation of the REE from the uranium matrix was achieved by high-performance ion chromatography (HPIC), reducing the isobaric interferences. After separation, the target analytes were analyzed in two different modalities. For high precision analysis, the separated analytes were collected and measured by ICP-MS in an “offline” fashion. For a rapid approach, the separated analytes were sent directly into an ICP-MS for “online” analysis. These methods have been demonstrated to accurately quantify the REE content in a well-characterized UOC sample.
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Loss of secretory IgA is common in the small airways of patients with chronic obstructive pulmonary disease and may contribute to disease pathogenesis. Using mice that lack secretory IgA in the ...airways due to genetic deficiency of polymeric Ig receptor (pIgR
mice), we investigated the role of neutrophils in driving the fibrotic small airway wall remodeling and emphysema that develops spontaneously in these mice. By flow cytometry, we found an increase in the percentage of neutrophils among CD45
cells in the lungs, as well as an increase in total neutrophils, in pIgR
mice compared with wild-type controls. This increase in neutrophils in pIgR
mice was associated with elastin degradation in the alveolar compartment and around small airways, along with increased collagen deposition in small airway walls. Neutrophil depletion using anti-Ly6G antibodies or treatment with broad-spectrum antibiotics inhibited development of both emphysema and small airway remodeling, suggesting that airway bacteria provide the stimulus for deleterious neutrophilic inflammation in this model. Exogenous bacterial challenge using lysates prepared from pathogenic and nonpathogenic bacteria worsened neutrophilic inflammation and lung remodeling in pIgR
mice. This phenotype was abrogated by antiinflammatory therapy with roflumilast. Together, these studies support the concept that disruption of the mucosal immune barrier in small airways contributes to chronic obstructive pulmonary disease progression by allowing bacteria to stimulate chronic neutrophilic inflammation, which, in turn, drives progressive airway wall fibrosis and emphysematous changes in the lung parenchyma.
The work described herein assesses the ability to characterize gold nanoparticles (Au NPs) of 50 and 100 nm, as well as 60 nm silver shelled gold core nanospheres (Au/Ag NPs), for their mass, ...respective size, and isotopic composition in an automated and unattended fashion. Here, an innovative autosampler was employed to mix and transport the blanks, standards, and samples into a high-efficiency single particle (SP) introduction system for subsequent analysis by inductively coupled plasma-time of flight-mass spectrometry (ICP-TOF-MS). Optimized NP transport efficiency into the ICP-TOF-MS was determined to be >80%. This combination, SP-ICP-TOF-MS, allowed for high-throughput sample analysis. Specifically, 50 total samples (including blanks/standards) were analyzed over 8 h, to provide an accurate characterization of the NPs. This methodology was implemented over the course of 5 days to assess its long-term reproducibility. Impressively, the in-run and day-to-day variation of sample transport is assessed to be 3.54 and 9.52% relative standard deviation (%RSD), respectively. The determination of Au NP size and concentration was of <5% relative difference from the certified values over these time periods. Isotopic characterization of the
Ag/
Ag particles (
= 132,630) over the course of the measurements was determined to be 1.0788 ± 0.0030 with high accuracy (0.23% relative difference) when compared to the multi-collector-ICP-MS determination.
While past research has examined the deleterious effects of racism on Asian Americans, fewer studies have investigated lesbian, gay, bisexual, and transgender (LGBT) Asian Americans' unique ...experiences of oppression and unbelonging within the broader LGBT community. Guided by intersectionality and minority stress theoretical frameworks, the present study examined the effect of discomfort due to one's race/ethnicity within the LGBT community on psychological well-being in a national sample of 480 LGBT Asian Americans from the Social Justice Sexuality Project. The moderating role of how important one considered their race/ethnicity to their identity was also examined. Regression analyses revealed that greater discomfort due to one's race/ethnicity within the LGBT community was associated with reduced psychological well-being for LGBT Asian Americans who viewed their racial/ethnic identity as moderately or highly important, whereas this association was not significant for LGBT Asian Americans who considered their racial/ethnic identity as less important. These findings highlight the necessity of examining the role of racial/ethnic discomfort in relation to LGBT Asian Americans' psychological well-being, as well as the extent to which LGBT Asian Americans consider their race/ethnicity as important.
What is the public significance of this article?
This study uses a national sample of LGBT Asian Americans to show that experiencing discomfort due to one's race/ethnicity within the LGBT community is associated with reduced psychological well-being. The effect of racial/ethnic discomfort for LGBT Asian Americans may also depend on how important they consider their race/ethnicity.
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