Watchara Sroykham

Effects of LED-backlit computer screen and emotional selfregulation on human melatonin production

Melatonin is a circadian hormone transmitted via suprachiasmatic nucleus (SCN) in the hypothalamus and sympathetic nervous system to the pineal gland. It is a hormone necessary to many human functions such as immune, cardiovascular, neuron and sleep/awake functions. Since melatonin enhancement or suppression is reported to be closely related to the photic information from retina, in this paper, we aim further to study both the lighting condition and the emotional self-regulation in different lighting conditions together with their effects on the production of human melatonin. In this experiment, five participants are in three light exposure conditions by LED backlit computer screen (No light, Red light (~650 nm) and Blue light (~470 nm)) for 30 minute (8-8:30 pm), then they are collected saliva both before and after the experiments. After the experiment, the participants are also asked to answer the emotional self-regulation questionnaire of PANAS and BRUMS regarding each light exposure condition. These results show that positive mood mean difference of PANAS between no light and red light is significant with p=0.001. Tension, depression, fatigue, confusion and vigor from BRUMS are not significantly changed while we can observe the significant change in anger mood. Finally, we can also report that the blue light of LED-backlit computer screen significantly suppress melatonin production (91%) more than red light (78%) and no light (44%).

The effects of perceiving color in living environment on QEEG, Oxygen saturation, pulse rate, and emotion regulation in humans

Light and color have been shown to have substantial physical, psychological and sociological effects on humans. Hence, an investigation on the effect of changes in light and color to the biological signals is a challenging problem. Five participants were measured the oxygen saturation (SpO2), pulse rate, and quantitative electroencephalogram (QEEG) in six colors (white, blue, green, yellow, red and black) of living environment for 5 minutes per color. Then all participants were asked to answer the emotional questionnaire of BRUMS and color performance for each color environment. The results showed brain activity of high beta wave (25-30 Hz) that associated with alertness, agitation, mental activity, and general activation of mind and body functions (at frontal lobes and temporal lobes) in red and yellow colored rooms were higher than blue, green, white and black colored rooms, respectively. It also had the relationship with the psychological effect (BRUMS). The amplitude asymmetry of beta wave (12-25 Hz) was highly attenuated in warm color (red and yellow colored rooms), moderately attenuated in cool color (green and blue colored room) and little attenuated in white and black colored rooms. The BRUMS showed that red and yellow yielded significant effect on anger (F=4.966, p=0.002) and confusion (F=3.853, p=0.008). Red and green color yielded high effect on vigor. Green color did not affect the depression. Blue color yielded moderate effect on confusion, tension and fatigue. White and black colors yielded low effect on any mood, but black color had no effect on vigor. In addition, we cannot observe any significant changes of pulse rate and blood oxygen saturation in each color. The results can possibly be used as the recommendation to design the room for either normal people or patients.

An investigation of microwave ablation for bone thermal drilling

Bone drilling is an important medical maneuver in a general orthopedic surgery. Hole drilling by using a conventional mechanical rotary drill is avoidable for a tiny bone chip and a corrosion of drill bit. An application of microwave energy to drill a hard cortical bone is even though proposed by some researchers but an investigation of thermal interaction at a drill site is still remain promising especially in a term of simulation. This research investigates a microwave thermal ablation for bone drilling through a 3D FEM solver. Microwave drill applicator was designed as an opened-tip coaxial antenna which inserted into a center of cortical bone model. Temperature pattern at hot spot and estimate drilled hole size was predicted finally. These useful simulation results can be basically applied in a design and development of a practical microwave bone drilling system in a near future.

A Study of an Intubated Tracheal Air Flow in a Cuff-Leak Testing Procedure

During an artificial ventilation, an endotracheal tube (ETT) must be inserted into patient airway and following by a balloon cuff blowing in order to function as an artificial airway. However, this implementation adversely affects to a tracheal tissue and all sensitive area and probably damaging a larynx and vocal cord zone. After ETT was removed, some patients always suffering with a larynx or tracheal edema symptom in which patient airway is narrowed due to a long term pressurization by the ETT balloon cuff and causing a difficulty in his spontaneous breathing. In general, a cuff leak test is performed in order to predict a larynx or tracheal edema possibility before ETT extubation from an air volume difference between an inspiration and expiration. In this paper, an investigation of an airflow pattern and air velocity which able to imply as an air volume in the cuff leak test process is proposed in order to understand and support a prediction of the tracheal edema. The study was performed with no edema and edema case at 10, 30 and 50% of trachea internal diameter. The simulations indicate that airflow pattern shows some affects when edema region is higher than 10%. Even though, this preliminary study was intently implemented in a simple intubated trachea model, however the obtain results guide us a practical information and will be used as a basic implementation for a further study, especially in case of variety in the ETT cuff shape and pressure or in cuff less ventilation even more complication case in the near future.

CORRELATION OF MORNING SALIVARY CORTISOL-MELATONIN RATIO WITH QEEG AND DELAYED RECALL IN AGING

Melatonin and cortisol are the main hormones of the circadian rhythm, which effect cognitive decline during aging. An imbalance of circadian rhythm hormones serves as an early sign of the progress of age-related disease and brain pathology in aging. The aim of this study was to determine the cortisol-melatonin ratio in relation to brain activity and cognitive function in aging. Sixty-four aging subjects were recruited from the brain healt hy project. The morning salivary of all subjects was collected for cortisol and melatonin levels analysis. The brain activity was recorded for 5 minutes in the eyes open condition and seven cognitive functions were assessed by the MoCA. The results were divided into a low ratio group and a high ratio group of cortisol-melatonin ratio. The low ratio group and the high ratio group differed in the delta-beta ratio at the left temporal lope (p < .05), and the delayed recall in the high ratio group was markedly higher than in the low ratio group. Moreover, the cortisol-melatonin ratio was strongly correlated with delayed recall (p < .05), the delta-beta ratio in the left temporal lope (p < .05), the theta alpha ratio in the left temporal lope (p < .05), and right temporal lope (p < .05). We found that a low cortisol-melatonin ratio corresponded to a high delta-beta ratio and a high thetaalpha ratio at the left temporal lobe with a low score of delayed recall function, but a high cortisol-melatonin ratio corresponded to a low delta-beta ratio and a low theta-alpha ratio at the left temporal lobe with a high score of delayed recall. The imbalance of the circadian hormone related to cognitive function and brain activity in aging could serve as a biomarker of age-related diseases.

A simulation of lung ablation using microwave thermal energy

Since a long time ago, one of a dangerous cancer that threatening human life is pulmonary cancer. Although, an open thoracic surgery is generally realized as a conventional gold standard for this malignant, but a new therapeutic method still be proposed as an alternative choice to deal with this hazard. In this paper, we present a FEM of microwave thermal treatment to ablate cancerous region in a simple lung model. Microwave energy was trialed at 2.45GHz, 10 Watts for 10 seconds by an opened-tip coaxial antenna. By concerning with an effect of airflow ventilation, a small bronchus also placed nearby the applicator position then a thermal distribution and coagulation pattern were studied. Although, our simple model in this simulation differ from a porous lung tissue, however at 60 C destructive temperature our investigation results in term of thermal distribution and destructive zone guide us some useful predictable information for a real ex vivo experiment in the near future work.