Microrheology with modulated optical nanoprobes (MOONs) Behrend, Caleb J.; Anker, Jeffrey N.; McNaughton, Brandon H. ...
Journal of magnetism and magnetic materials,
05/2005, Volume:
293, Issue:
1
Journal Article, Conference Proceeding
Peer reviewed
Metal-capping of one hemisphere of a nano or microparticle breaks the particle's optical symmetry, allowing its orientation to be tracked using fluorescence and reflection. Tracking orientation and ...rotation allows the torques acting on the particles be inferred. In addition to serving as rotational nanoviscometers these probes report on local Brownian, magnetic and biomechanical torques.
Implanted medical device-associated infections are a leading cause of fixation failure, and early diagnosis is the key to successful treatment. During infection, acidosis near the implant plays a ...role in antibiotic resistance and low pH is a potential infection indicator. Herein, we describe a pH sensor which attaches to the implants to noninvasively image local pH with high spatial resolution. The sensor has two layers: a scintillator layer which emits 620 and 700 nm light upon X-ray irradiation and a pH indicator layer containing bromocresol green dye that absorbs 620 nm luminescence in neutral/basic pH and passes 700 nm light at all pHs. We also developed a dedicated imaging system capable of scanning relatively large specimens through thick tissues. A focused X-ray beam irradiates one spot on the sensor, and the 620 to 700 nm peak ratio is measured to determine the local pH; images are acquired by scanning the X-ray beam across the surface and measuring the pH point-by-point. The sensor was covered with varying thickness slices of chicken breast tissue (0–19 mm) to evaluate how the tissue affects the peak intensity and ratio. Thick tissues attenuated both 620 and 700 nm light, with more attenuation at 620 nm than 700 nm. Although this spectral distortion shifted the pH calibration curve, the effect could be corrected for using a scintillator film region with no pH indicator layer as a spectral reference. The sensor was attached to an orthopedic plate affixed to a human cadaveric tibia and imaged through tissue. This approach provides both high spatial resolution from focused X-ray excitation and surface chemical specificity from the indicator dye, providing a tool for imaging local pH through tissue.
In HBV/HIV-co-infected individuals, the course of hepatitis B is aggravated, leading to higher morbidity and mortality rates. Increasing evidence suggests an important role for hepatitis B surface ...antigen (HBsAg) quantification in monitoring treatment efficacy in HBV monoinfection. However, data concerning any HBsAg decline during treatment of HBV/HIV coinfection are limited. Fifty-one HBV/HIV-co-infected patients were retrospectively followed for a mean of 43 months (median 2 years, interquartile range 2 years). Baseline and on-treatment parameters were associated with longitudinal HBsAg levels. At baseline, serum HBsAg levels were comparable between patients on antiretroviral therapy (ART; n=43) and patients without (n=8). Longitudinally, HBsAg decreased in ART patients (-0.20±0.09 log(10) IU/mL/y), but slightly increased in subjects without therapy (0.22±0.26 log(10) IU/mL/y; p<0.001). In 58% of the ART subjects an HBsAg decline >10% was seen during the initial 24 mo. They showed higher baseline CD4 counts (401±42 versus 265±50 cells/μL, p=0.03), and had significantly higher CD4 counts at the last follow-up compared to patients without a decline (506±39 versus 310±51 cells/μL, p=0.01). A significant correlation was found between HBsAg decline from baseline to the last follow-up and the absolute increase of CD4 cells (r=0.44, p=0.003), as well the last CD4 count (r=0.41, p=0.006). This association was strongest in patients with complete suppression of HBV-DNA and HIV-RNA at the last follow-up visit. The highest HBsAg decline (-1.63±0.32 versus -0.43±0.24 log(10) IU/mL, p=0.001), and yearly HBsAg decline (-0.47±0.13 versus -0.19±0.12 log(10) IU/mL, p=0.03), were found in patients with CD4 increases >100 cells/μL at the last follow-up (n=21, 49%). Four cases of HBsAg loss were observed (8%). HBsAg declines steadily in >50% of HBV/HIV patients on ART. Long-term follow-up of HBV/HIV-co-infected patients is needed to identify distinct HBsAg patterns. Increasing CD4 counts indicating the restoration of immune competence in HBV/HIV-co-infected patients is associated with a stronger HBsAg decline.
Magnetically-modulated optical nanoprobes (MagMOONs) are micro and nano particles that emit different fluxes of light in different orientations, and that rotate in changing magnetic fields. The ...particles blink as they rotate, allowing in situ background subtraction and chemical imaging with individual particles. The probes also function as torque sensors to measure the drag on the particle and local rheological properties.
ABSTRACT Do abnormally high or low audit fees reflect audit quality? In this paper, we re-examine this issue after controlling for the confounding effect of audit hours by using a sample of public ...firms in the Korean audit market, which publicly discloses both audit fees and audit hour information. While we do not find a significant association between abnormally high audit fees and audit quality, we find that abnormally low audit fees are associated with larger discretionary accruals and a higher likelihood of meeting or beating analyst earnings forecasts. Further, we find that the relationship between abnormally low audit fees and audit quality indicators persists regardless of the level of audit hours. To the extent that audit hours represent audit effort, these findings suggest that greater audit effort alone may not lead to higher audit quality as fee pressure from abnormally low fees may discourage the provision of high-quality audit services. JEL Classifications: M42; M48.
Former slaves, with no prior experience in electoral politics and with few economic resources or little significant social standing, created a sweeping political movement that transformed the South ...after the Civil War. Within a few short years after emancipation, not only were black men voting but they had elected thousands of ex-slaves to political offices. Historians have long noted the role of African American slaves in the fight for their emancipation and their many efforts to secure their freedom and citizenship, yet they have given surprisingly little attention to the system of governance that freedpeople helped to fashion. Justin Behrend argues that freedpeople created a new democracy in the Reconstruction era, replacing the oligarchic rule of slaveholders and Confederates with a grassroots democracy.
Reconstructing Democracytells this story through the experiences of ordinary people who lived in the Natchez District, a region of the Deep South where black political mobilization was very successful. Behrend shows how freedpeople set up a political system rooted in egalitarian values wherein local communities rather than powerful individuals held power and ordinary people exercised unprecedented influence in governance. In so doing, he invites us to reconsider not only our understanding of Reconstruction but also the nature and origins of democracy more broadly.
Background: This study compared the clinical complications, radiographic measurements of deformity, and quality of life outcomes for patients with de novo scoliosis undergoing thoracolumbar fusions ...for spinopelvic fixation (SPF) utilizing unilateral S2 alar-iliac (S2AI) screw or unilateral iliac bolt fixation.
Methods: This retrospective review was performed in 29 patients who underwent SPF at one institution; 10 patients received unilateral S2AI screws, and 19 patients received unilateral iliac bolts. The following variables were studied: reoperation rates, pseudarthrosis, sacral insufficiency fracture, hardware prominence, infection, proximal junctional kyphosis (PJK), deformity correction (radiographs), windshield wipering, hardware fracture, and hardware removal. Outcomes were analyzed utilizing both the visual analog scale (VAS) and Oswestry Disability Index (ODI). The mean follow-up period was 27 months.
Results: The reoperation rate for unilateral S2AI screws was 30% vs. 53% for unilateral iliac bolts (P = 0.43); reoperations were performed with a 1:5 ratio for infection, a 1:4 ratio for pseudarthrosis, and 1:1 a ratio for PJK comparing S2AI screws to iliac bolts, respectively.
Conclusion: There were no significant differences in postoperative complications and reoperation rates between unilateral S2AI screws and unilateral iliac bolts utilized for SPF. For the S2AI screw group, there were no instances of hardware prominence or need for removal. The use of unilateral S2AI screws resulted in adequate fixation and comparably low complication rates.
The multidisciplinary and sequential nature of cancer care makes continuity of care for patients difficult. Cancer patients have often known their general practitioners (GPs) for years and are often ...in constant contact with them. Objective(s). We examined German GPs' views on their involvement in the care of cancer patients.
We conducted semi-structured interviews with 30 German GPs. Purposeful sampling was applied to secure maximum heterogeneity. Interviews were recorded, transcribed and then analyzed using qualitative content analysis according to Mayring.
GPs perceive a clear involvement in the latter phase of cancer care but a mainly sporadic role (as and when required) in earlier phases. They think that greater care contributions from GPs are generally beneficial to cancer patients, as their ability to take the patient's history, surroundings and co-morbidities into account enables them to provide more patient-centred care. GPs want to stay involved and to know how their cancer patients are progressing, and they complain about slow or non-existent information sharing between providers, as well as insufficient care coordination. They pro-actively try to overcome these obstacles through direct contact with patients and physicians, and by building networks of trusted care providers.
Given their long-lasting and close relationships with cancer patients, GPs are in a position to accompany them throughout the whole process of cancer care. However, such general involvement is as yet uncommon. Shared care models may have the potential to take into account the complementary character of primary and specialist care.
ABSTRACT The Large Magellanic Cloud (LMC) presents a unique environment for pulsar population studies due to its distinct star formation characteristics and proximity to the Milky Way. As part of the ...TRAPUM (TRAnsients and PUlsars with MeerKAT) Large Survey Project, we are using the core array of the MeerKAT radio telescope (MeerKAT) to conduct a targeted search of the LMC for radio pulsars at L-band frequencies, 856–1712 MHz. The excellent sensitivity of MeerKAT, coupled with a 2-h integration time, makes the survey 3 times more sensitive than previous LMC radio pulsar surveys. We report the results from the initial four survey pointings which have resulted in the discovery of seven new radio pulsars, increasing the LMC radio pulsar population by 30 per cent. The pulse periods of these new pulsars range from 278 to 1690 ms, and the highest dispersion measure is 254.20 $\mathrm{ pc} \, \mathrm{ cm}^{-3}$. We searched for, but did not find any significant pulsed radio emission in a beam centred on the SN 1987A remnant, establishing an upper limit of 6.3 $\mu \mathrm{ Jy}$ on its minimum flux density at 1400 MHz.
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