Session Detail

Conventional antimicrobial susceptibility testing (AST) is time-consuming, resulting in high mortality and rising bacte-rial drug resistance. Rapid antibiotics determination assits medical doctors to make correct prescriptions and save more lives. In this study, we developed a technique combining opti-cal diffusometry and vancomycin-modified beads-based as-says to detect microorganisms and achieve rapid AST. Ac-cording to Stokes-Einstein equation, the diffusion coefficient is inversely proportional to the particle diameter. The particle diameter changes after the beads conjugate with bacteria, causing a diffusivity decline. We used vancomycin-modified beads to experiment with three types of bacteria, including Gram-negative bacteria Escherichia coli, Pseudomonas aeru-ginosa, and Gram-positive bacteria of Staphylococcus aureus. Our final results showed that the system possessed ad-vantages of the ability to detect multiple drugs at the same time, time-saving (< 2 h), small sample volume (5 µL), and low initial bacterial count (105 CFU/mL). The technique provided a practical means to achieve rapid therapy against microbial diseases in the near future.

 

Abstract— In nonlinear optical imaging of biological specimens, more than half of the generated luminescence signal is lost, when signal collection is performed in the epi-illuminated geometry. In this study, we enhanced the collected luminescence signal by the use of alternating multiply-coated layers of tantalum pentoxide (Ta2O5) and silicon dioxide (SiO2) on standard microscope cover glasses that has high transmission in the near-infrared wavelength region and high reflection of the visible, luminescence signal. Our coating is biocompatible, allows visual examination of the specimens and optimize collection of the luminescence signal. We demonstrated this approach on a number of specimens including sulforhodamine solution, fluorescence microspheres, and labeled 3T3 cells. In all cases, the use of coated cover glass enhanced signal, optimally by a factor of about 2. Image analysis of labeled 3T3 cells also shows signal enhancement did not contribute to additional photobleaching. Our results show that properly designed coated cover glass can enhance detected signal in multiphoton microscopy and result in improved image quality

 

According to the theory of neural plasticity, brain can com-pensate the impaired function by rebuilding the neural circuit. The aim of this study is to apply patterned stimuli and to monitor hymodynamic changes in the brain. Nine stroke subjects were recruited for investigating the ef-fect of cortical intermittent TBS (iTBS) electrical stimulation. The subjects were asked to perform the cycling tasks to induce the cortical activation. During cycling, brain hemodynamic activity and kinematic information were measured before and after the stimulation. A concurrent stimulation with iTBS1200 and direct current was delivered during the stimulation ses-sion. fNIRS signal was analyzed as the hemodynamic response function as concentration changes in hemoglobin in time do-main and frequency domain. For kinematic information, the surface EMG on quadriceps muscles were for analyzing the symmetry between affected and unaffected leg using the shape symmetry index (SSI) and area symmetry index (ASI), and torque and speed information of ergometer to obtain the smoothness. Our NIRS data showed the decreasing value in power spec-trum density band I (0.01Hz~0.02Hz) and increasing in band II (0.02Hz~0.05Hz), and band III (0.05Hz~0.15Hz) during and after the stimulation which suggest the brain might respond to the stimulation. The enhanced regional brain activation value also found in primary motor cortex (PMC), sensorimotor cortex (SMC), and secondary sensory cortex (S2). The sym-metry indices of SSI and ASI are significant different between healthy and stroke subjects. However, it was not significant difference before and after the stimulation. The advantage of the stimulation technique used in this study is the highly flexi-bility and compatibility with the functional brain activity monitor techniques like fNIRS. Although the stimulation effects to blood flow oscillation bands still need to be clarified, it is a potential stimulation technique for neural degeneration diseases.

 

Diffuse correlation spectroscopy (DCS) is a non-invasive method to monitor cerebral blood flow (CBF). CBF is an important biomarker which controls the supply of oxygen, metabolic consumption, and byproduct clearance in the brain. Clinical potential of DCS for monitoring CBF in cerebrovascular diseases, such as stroke, has been studied. We developed a fast DCS system that is capable of detecting cerebral hemodynamic oscillation during cardiac frequency. Abnormal hemodynamics was monitored by our system in the rodent model of common carotid artery ligation (CCAL), ventilative hyperoxia and hypoxia. Furthermore, inter-hemispheric correlation coefficient (IHCC) during the hemodynamic oscillation will be measured in rodent model of ischemic stroke using fast DCS. To test the potential of using IHCC in stroke detection, the changes in IHCC from normal and ischemic stroke will be evaluated.

 

In recent studies, the implementation of fiber-optic systems combined with Ca2+ fluorescent indicators for neural activity research has increased due to its deep probing brain region and applicability of freely moving animals. During fluorescent targeting, it was never 100% specific, hence, it was important to prevent unnecessary tissue exposure to light. However, in most of the studies, large brain regions illuminated by multi-mode optical fiber that exceeded the fluorescent indicator targeting regions would cause unnecessary signals recorded by the system. Furthermore, motion and physiological artifact during freely moving animals recording also made signals contaminated. Therefore, we demonstrated a dual-wavelength optical recording system to reduce the influence of recording artifact and introduced Monte Carlo simulation before experiment to predict the light intensity profile in brain tissue which was valuable in determining a suitable protocol for specific experiment.