Synthesis of low-melting-point metallic nanoparticles with an ultrasonic nanoemulsion method

A one-step, economical nanoemulsion method has been introduced to synthesize low-melting-point metallic nanoparticles. This nanoemulsion technique exploits the extremely high shear rates generated by the ultrasonic agitation and the relatively large viscosity of the continuous phase - polyalphaolefin (PAO), to rupture the molten metal down to diameter below 100 nm. Field's metal nanoparticles and Indium nanoparticles of respective average diameters of 15 nm and 30 nm have been obtained. The nanoparticles size and shape are determined by transmission electron microscopy (TEM). Their phase transition behavior is examined using a differential scanning calorimeter (DSC). It is found that these nanoparticles dispersed in PAO can undergo reversible, melting-freezing phase transition, and exhibit a relatively large hysteresis. The experimental results suggest that the nanoemulsion method is a viable route for mass production of low-melting nanoparticles.

Low-temperature sol-gel-derived nanosilver-embedded silane coating as biofilm inhibitor

Silver nanocomposite coatings are prepared by the sol-gel method for the prevention of biofilm formation on the surface of medical implanted devices. High-temperature processing of such coatings can lead to diffusion of nanosilver and reduce the amount of available silver particles for long-term effects. Using a low-temperature sol-gel method, we have successfully prepared silane-based matrices, phenyltriethoxysilane (PhTEOS), containing different amounts of Ag nanoparticles. The incorporation of a silver salt into the sol-gel matrix resulted in a desired silver release rate, i.e. high initial release rate followed by a lower sustained release for more than 15 days, as determined by inductively coupled plasma mass spectrometry (ICP-MS). Scanning electron microscopy (SEM) has been employed to investigate the morphology of the film surfaces before and after immersion in a nutrient-rich bacterial suspension of approximately 10⁸ CFU ml⁻¹, which was incubated for up to 30 days at 37 °C. It was found that thin films containing 35 nm particles could prevent the formation of biofilm for over 30 days. The presence of surface silver before and after 3, 9 and 15 days immersion was confirmed by x-ray photoelectron spectroscopy (XPS).

Abstract P1-01-20: Validation of MSKCC Nomogram in Predicting Sentinel Lymph Node Metastasis of a Chinese Breast Cancer Population

Background: The Memorial Sloan-Kettering Cancer Center (MSKCC) developed a nomogram to predict the presence of sentinel lymph node (SLN) metastasis in breast cancer patients. Our study was designed to validate the clinical value of the MSKCC nomogram in Chinese early-stage breast cancer population.

Methods: Data were collected from 524 patients with successful SLN biopsy who were treated during 2005 March to 2009 October. Positive SLN metastasis was found in 154 patients. Touch imprint cytology (TIC) and serial section with H&E staining were performed routinely on each sentinel node. Univariate analysis and logistic regressions tested whether a characteristic was correlated with the SLN positivity. MSKCC nomogram was used to estimate probability of SLN involvement and compared with actual probability after grouping into deciles. A ROC curve was drawn and predictive accuracy was assessed by calculating the area under the receiver-operating characteristic (ROC) curve.

Results: It was shown that age, tumor size, histological grade and lymphovascular invasion was correlated with the probability of SLN metastasis by univariate analysis (P<0.05). By multivariate analysis, tumor size and lymphovascular invasion were identified as independent predictors of SLN metastasis. The odds ratio (OR) of the lymphovascular invasion was 9.462(95% CI 5.551-16.130)while OR of tumor size was 1.429(95% CI 1.142-1.788). The trend of actual probability in various decile groups was comparable to the predicted probability. Patients in the group with the least probability of a positive SLN predicted by the nomogram (≥10 decile) were all diagnosed with a negative SLN by serial section by H&E staining. Three patients in our collective with extremely high probability (≥90) were all diagnosed as positive SLN by pathology. The area under the ROC curve was 0.757 as compared to 0.754 in the original population. Conclusion: As far as we know, this is the first study designed to evaluated the MSKCC nomogram in Chinese early breast cancer population. The MSKCC nomogram that predicts metastasis of breast cancer in the sentinel lymph node performed good in a Chinese breast cancer population. Though the nomogram cannot be an alternative of SLN biopsy, it could provide a clinical accessory in the preoperative discussion with patients, especially in the very high or very low risk of patients. The nomogram could be used in very low risk patients to safely avoid a SLN procedure, thereby reducing postoperative morbidity, whereas the rate could be as high as 7% in the literature. While for patients with very high risk estimated by the nomogram, axillary lymph node dissection could be recommended directly. The shortcoming of the nomogram is that clinical and pathological parameters include detail histological diagnosis of the primary tumor before the final decision for surgical procedure.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P1-01-20.

Abstract P1-01-07: Touch Imprint Cytology for Intraoperative Evaluation of Sentinel Lymph Node in Patients with Early-Stage Breast Cancer: A Five-Year Experience

Background: Accurate intraoperative diagnosis of sentinel lymph node (SLN) metastases enables the selection of patients for axillary lymph node dissection during the same operation and reduces the need for re-operation. Touch imprint cytology (TIC) serves as a main intraoperative assessment of SLNs in our institute for over five years. The purpose of the present study is to evaluate the clinical value of TIC as an intraoperative assessment for the diagnosis of SLN.

Methods: Patients treated for early-stage breast cancer between Feb-2005 and May-2010 enrolled in the study. TIC was routinely performed intraoperatively, the result of which was correlated with definitive histological assessments of serial section with Hematoxylin-Eosin staining. Subsequent immunohistochemistry staining with CK-19 and MUC-1 were performed for research purposes. The Memorial Sloan-Kettering Cancer Center (MSKCC) nomogram was applied in this retrospective study to estimate probability of SLN involvement of each case. Results: A total of 1,077 patients with early-stage breast cancer enrolled in the study, and 3,048 SLNs were successfully harvested during the surgeries. Among those, 265 (24.6%) patients proved to have at least one SLN that was positive for carcinoma. Altogether, 397 (13.0%) involved nodes were removed from patients in the aforementioned patient pool. Based on the final pathology report, the sensitivity, specificity and overall accuracy of TIC was 83.4%, 99.0% and 95.2%, respectively on a per patient basis, and 78.3%, 99.4% and 96.7%, respectively on a per node basis. The sensitivity for macrometastasis and micrometastasis are 88.6% and 39.3%, respectively on a per patient basis, while 87.4% and 31. 3%, respectively on a per node basis. Of the patients included in this study, 98.7% had a positive SLN within their first three harvested SLNs. All the patients who were at a <10% chance of SLNs metastases according to the MSKCC nomogram were proved to be node negative by the final pathology. Conclusion: TIC is feasible and is able to detect macrometastasis in SLNs with an acceptable accuracy for clinical use in early-stage breast cancer patients while its ability to detect micrometastasis is limited. Limiting intraoperative TIC to the first three harvested SLNs in the diagnosis of SLN metastasis may make this diagnostic procedure significantly cheaper and easier for pathologists to perform. The MSKCC nomogram could be applied as a screening tool. Intraoperative assessment for SLNs, such as TIC, could be spared for patients with extremely low MSKCC scores (<10%).

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P1-01-07.

Growth and structure of crystalline silica sheet on Ru(0001)

Thin SiO₂ films were grown on a Ru(0001) single crystal and studied by photoelectron spectroscopy, infrared spectroscopy and scanning probe microscopy. The experimental results in combination with density functional theory calculations provide compelling evidence for the formation of crystalline, double-layer sheet silica weakly bound to a metal substrate.

Ceiling-mounted personalized ventilation system integrated with a secondary air distribution system--a human response study in hot and humid climate

The benefits of thermal comfort and indoor air quality with personalized ventilation (PV) systems have been demonstrated in recent studies. One of the barriers for wide spread acceptance by architects and HVAC designers has been attributed to challenges and constraints faced in the integration of PV systems with the work station. A newly developed ceiling-mounted PV system addresses these challenges and provides a practical solution while retaining much of the apparent benefits of PV systems. Assessments of thermal environment, air movement, and air quality for ceiling-mounted PV system were performed with tropically acclimatized subjects in a Field Environmental Chamber. Thirty-two subjects performed normal office work and could choose to be exposed to four different PV airflow rates (4, 8, 12, and 16 L/s), thus offering themselves a reasonable degree of individual control. Ambient temperatures of 26 and 23.5 degrees C and PV air temperatures of 26, 23.5, and 21 degrees C were employed. The local and whole body thermal sensations were reduced when PV airflow rates were increased. Inhaled air temperature was perceived cooler and perceived air quality and air freshness improved when PV airflow rate was increased or temperature was reduced.

PRACTICAL IMPLICATIONS

The newly developed ceiling-mounted PV system offers a practical solution to the integration of PV air terminal devices (ATDs) in the vicinity of the workstation. By remotely locating the PV ATDs on the ceiling directly above the occupants and under their control, the conditioned outdoor air is now provided to the occupants through the downward momentum of the air. A secondary air-conditioning and air distribution system offers additional cooling in the room and maintains a higher ambient temperature, thus offering significant benefits in conserving energy. The results of this study provide designers and consultants with needed knowledge for design of PV systems.