Measurement of Charge and Refractive Indices in Optically Trapped and Ionized Living Cells.

The post-ionization dynamics of chemo-treated and untreated 4T1 breast cancer cells ionized by laser trapping techniques are studied. We have determined each cell's charge and refractive index by developing a theoretical model for the forces determining the post-ionization dynamics. The shift in a cell's refractive index due to an intense oscillating electric field was studied, and the results are reported here. We observed that a trapped cell, as it becomes charged, will eventually exit the trap perpendicular to the beam's direction; this means that the electric force of the cell overcomes the trapping force. As a result, the cell's conductivity changes due to the oscillating field, causing a decrease in the cell's refractive index.

Magnetic Resonance Detection of Gas Microbubbles via HyperCEST: A Path Toward Dual Modality Contrast Agent.

Gas microbubbles are an established clinical ultrasound contrast agent. They could also become a powerful magnetic resonance (MR) intravascular contrast agent, but their low susceptibility-induced contrast requires high circulating concentrations or the addition of exogenous paramagnetic nanoparticles for MR detection. In order to detect clinical in vivo concentrations of raw microbubbles via MR, an alternative detection scheme must be used. HyperCEST is an NMR technique capable of indirectly detecting signals from very dilute molecules (concentrations well below the NMR detection threshold) that exchange hyperpolarized 129 Xe. Here, we use quantitative hyperCEST to show that microbubbles are very efficient hyperCEST agents. They can accommodate and saturate millions of 129 Xe atoms at a time, allowing for their indirect detection at concentrations as low as 10 femtomolar. The increased MR sensitivity to microbubbles achieved via hyperCEST can bridge the gap for microbubbles to become a dual modality contrast agent.

Volunteerism and Cardiovascular Health: The HCHS/SOL Sociocultural Ancillary Study.

OBJECTIVES: The objective of this study was to examine the association between volunteerism and favorable cardiovascular health (CVH) among Hispanics/Latinos living in the US. METHODS: Data from the Hispanic Community Health Study/Study of Latinos (2008-2011) Sociocultural Ancillary Study were used (N = 4,926; ages 18-74 years). Favorable CVH was defined as positive profiles of all major CVD risk factors: low total serum cholesterol, blood pressure, and body mass index; not having diabetes; and not smoking. Survey-weighted logistic regression models were adjusted for sociodemographic, lifestyle, and psychological factors. In secondary analyses, we tested whether the volunteerism-CVH association was modified by sex, age, or years lived in the US (<10 vs. ≥10 years; a proxy acculturation measure). RESULTS: Prevalence of volunteerism was 14.5%. Compared to non-volunteers, volunteers had 1.67 higher odds of favorable CVH in the fully-adjusted model (Odds Ratio [OR] = 1.67, 95% Confidence Interval [CI] = 1.11, 2.52). There was evidence of effect modification by acculturation; only volunteers who had lived in the US ≥10 years had 2.41 higher odds of favorable CVH (OR = 2.41, 95% CI=1.53, 3.80). There was no evidence of effect modification by sex or age. CONCLUSIONS: Volunteerism was associated with favorable CVH among US Hispanics/Latinos.

Single cell ionization by a laser trap: a preliminary study in measuring radiation dose and charge in BT20 breast carcinoma cells.

In this work, a preliminary study in the application of a laser trap for ionization of living carcinoma cells is presented. The study was conducted using BT20 breast carcinoma cells cultured and harvested in our laboratory. Each cell, for a total of 50 cells, was trapped and ionized by a high intensity infrared laser at 1064 nm. The threshold radiation dose and the resultant charge from the ionization for each cell were determined. With the laser trap serving as a radiation source, the cell underwent dielectric breakdown of the membrane. When this process occurs, the cell becomes highly charged and its dielectric susceptibility changes. The charge creates an increasing electrostatic force while the changing dielectric susceptibility diminishes the strength of the trapping force. Consequently, at some instant of time the cell gets ejected from the trap. The time inside the trap while the cell is being ionized, the intensity of the radiation, and the post ionization trajectory of the cell were used to determine the threshold radiation dose and the charge for each cell. The measurement of the charge vs ionization radiation dose at single cell level could be useful in the accuracy of radiotherapy as the individual charges can collectively create a strong enough electrical interaction to cause dielectric breakdown in other cells in a tumor.

Infant male circumcision: healthcare provider knowledge and associated factors.

BACKGROUND AND OBJECTIVES: The emerging science demonstrates various health benefits associated with infant male circumcision and adult male circumcision; yet rates are declining in the United States. The American Academy of Pediatrics and the Centers for Disease Control and Prevention recommend that healthcare providers present evidence-based risk and benefit information for infant male circumcision to parent(s) and guardian(s). The purpose of this study was to assess providers' level of infant male circumcision knowledge and to identify the associated characteristics. METHODS: An online survey was administered to healthcare providers in the family medicine, obstetrics, and pediatrics medical specialties at an urban academic health center. To assess infant male circumcision knowledge, a 17 point summary score was constructed to identify level of provider knowledge within the survey. RESULTS: Ninety-two providers completed the survey. Providers scored high for the following knowledge items: adverse event rates, protects against phimosis and urinary tract infections, and does not prevent hypospadias. Providers scored lower for items related to more recent research: protection against cervical cancer, genital ulcer disease, bacterial vaginosis, and reduction in HIV acquisition. Two models were constructed looking at (1) overall knowledge about male circumcision, and (2) knowledge about male circumcision reduction in HIV acquisition. Pediatricians demonstrated greater overall infant male circumcision knowledge, while obstetricians exhibited significantly greater knowledge for the HIV acquisition item. CONCLUSION: Providers' knowledge levels regarding the risks and benefits of infant male circumcision are highly variable, indicating the need for system-based educational interventions.

Youth participation in a community campaign to pass a clean indoor air ordinance.

Because of the harmful effects of secondhand smoke, communities are organizing to pass clean indoor air policies. With youth being considered one of the most vulnerable populations to this health hazard, it can be strategic to campaigns and beneficial to the youth's development to involve them in efforts to control this toxin. However, youth participation in health campaigns is limited because of barriers inherent in these initiatives. This article presents lessons learned from a qualitative case study on the youth involvement in a successful local clean indoor air campaign. Through the analysis of semistructured interviews with the adult members of the campaign, group interviews and questionnaire completion by the youth members of the campaign, and additional insight made possible by participant observation, recommendations are provided to engage and sustain youth involvement in local public health initiatives.