We studied the quantum dot-liposome complex (QLC), which is the giant unilamellar vesicle with quantum dots (QDs) incorporated in its lipid bilayer. A spin coating method in conjunction with the electroformation technique yielded vesicles with highly homogeneous unilamellar structure. We observed QD size dependence of the QLC formation: QLCs form with blue, green and yellow-emission QD (core radius ~1.05 nm, 1.25 nm and 1.65 nm) but not with red-emission QD (core radius ~2.5 nm). In order to explain this size dependence, we made a simple model explaining the QD size effect on QLC formation in terms of the molecular packing parameter and the lipid conformational change. This model predicts that QDs below a certain critical size (radius ≈ 1.8 nm) can stably reside in a lipid bilayer of 4 -5 nm in thickness for Egg-PC lipids. This is consistent with our previous experimental results. In the case of red-emission QD, QD-aggregations are only observed on the fluorescent microscopy instead of QLC. We expected that the reduction of packing parameter (P) would lead to the change of specific QD radius. This prediction could be verified by our experimental observation of the shift of the specific QD size by mixing DOPG.

We prepare giant Quantum dot-Liposome Complexes (QLCs). Quantum dots (QDs) incorporated inside liposome above 10 μm. QLCs is made by using the electro-swelling method combined with spin coating techniques. Three types of PC lipids and asolectin lipid are used for QLCs with HDA (hexadecylamine) coated QDs, which ranged from blue- (diameter ~2.1 nm) to red-emission (diameter ~5.0 nm). As expected, (blue- or) green-emission QDs (smaller than) comparable to the thickness of PC lipid bilayer (~4 nm) are successfully formed QLCs, but QDs bigger than that fail to reproduce. This observation is well-consistent with those reported by Gopakumar et al. Surprisingly, all QDs irrespective of their size are, contrary to PC lipids, successfully loaded into asolectin lipid bilayer. In order to understand what makes different behaviors between PC and asolectin lipids on QLC formation, we suggest a theoretical model based on a geometrical assumptions for deformed lipid bilayer surrounding QD. The main advantage of this model is that the critical size Rcr of QD radius can be decided without calculating elastic free energy. As a result, it predicts that only QDs below the critical size (diameter ~3.0 nm) can be loaded in a typical PC-lipid, but all size of QDs can be incorporated into asolectin bilayer under the assumption of two different curvatures on deformed monolayer.

This study analyzes the response of increasing radiation dose to the pork tenderloin tissue. Considering its significant cell structure, pork tenderloin tissue samples are selected for the experimental objects to measure their electrical impedance characteristics. This study proposes and investigates an effective approach to characterize the variation of the internal change of the components of pork tenderloin tissues caused by radiation. Changes in the pork tenderloin tissues are that the gap of the myotome is more far apart with increase of radiation dose because of the destroyed Myofibrils under the damage. With the increase of radiation dose, the impedance value of the pork tenderloin tissue decreases. Each of mean differences in the impedance values before and after irradiation dose under 1 Gy, 2 Gy and 4 Gy show 0.55±0.03, 1.09±0.14 and 1.97±0.14, respectively. However, the mean difference substantially increases to 13.08±0.16 at irradiation dose of 10 Gy. Thus, the cell membrane shows the most severe rupture at a radiation dose of 10 Gy. Changes in the microstructure of the irradiated pork tenderloin tissue samples are also checked and validated by a transmission electron microscope.

OBJECTIVE: To invastgate feasibility of low-dose contrast agent in cerebral computed tomography angiography (CTA) to alleviate side effects. METHOD: Siemens’ Somatom Definition AS+CT scanner, Heine’s blood pressure monitor G7-M237 (BP cuff) and Ultravist contrast agent (370 mg Iodine/ml) are used. CTA is acquired using following scan parameters including slice thickness of 1mm, image acquisition parameters of 128×0.6 mm, pitch size of 0.8 mm, 175 effective mAs, 120 kVp tube voltage, scan delay time of 3 seconds, and the scan time of 4 seconds. This study is conducted by securing the IV route in the left antecubital vein before injection of contrast agent, wrapping BP cuff around the branchial artery of the opposite right arm after setting the pressure to 200 mmHg. Then, the injection rate of the contrast agent is fixed at 4.5 cc/sec and contrast agent was injected in three different amounts (70, 80, and 100 cc). Bp cuff is released from this moment when HU value reachs 100. RESULT: In this study, the mean HU values measured from common carotid artery are 412.45±5.89 when injecting 80cc contrast agent and using BP cuff and 399.64±5.51 when injecting 100 cc contrast agenet and not using BP cuff, respectively. In middle cerebral artery M1, the mean HU values are 325.23±38.29 when injecting 80cc contrast agent and using BP cuff and 325.00±30.63 when injecting 100cc contrast agent blood and not using pressure cuff, respectively. Difference of mean HU values is not statistically significant (p >  0.05) with and without using BP cuff. CONCLUSION: This study demonstrates that reducing amount of contrast agent is possible when the right brachial artery is compressed using BP cuff. Study results indicate that reducing 20% injection of contrast agent in CT cerebrovascular angiography can still yield comparable imaging results with conventional contrast angent usage, which implies that less side effects are expected with a contrast agent injection. Thus, this study can serve as a reference for potential reducing side effect during CT cerebrovascular angiography.