**7. Acknowledgment**

This work was supported by the Nihon University Multidisciplinary Research Grant in 2010 and 2011.

#### **8. References**

352 Infrared Spectroscopy – Life and Biomedical Sciences

Fig. 16. Result of ON/OFF decision using proposed method (imagined grasping tasks)

Time (s)

100 125 150 175 200 225 250

R T T R R T R

In this study we proposed a new detection method that uses oxy-Hb and its differential as indexes for application to the NIRS-BCI rehabilitation system, detecting brain activity from the data measured using NIRS. First, we developed a BCI system to control robot arm using NIRS, and confirmed that NIRS-BCI system can control machine and device. When a detection method with a simple threshold is employed, no stable operation was made during the tasks. This study proposes a method by which oxy-Hb is plotted on the horizontal axis and the differential of oxy-Hb on the vertical axis, and brain activity is judged from the area of the plotted trajectory. As a result, we confirmed that the proposed detection method enables highly accurate detection with little time delay compared with the conventional detection method, during both grasping tasks and imagined grasping


oxy-Hb d(oxy-Hb)/dt signal

Differential

value (mM

 cm/s)

OFF

ON

Next, we applied NIRS-BCI system developed for rehabilitation. We also confirmed that the proposed detection method enables highly accurate detection compared with the detection method with a simple threshold during both grasping tasks and imagined grasping tasks. These results confirm the validity of the proposed detection method for the NIRS-BC rehabilitation system. We gathered experiment data from healthy men in the present study, but in future studies, we will develop portable NIRS-BCI rehabilitation system, and conduct

Furthermore, the detection method proposed in this study uses the oxy-Hb level and its differential alone as indexes, so it is applicable to the brain activity of the prefrontal area while the brain is performing cognition tasks, where deoxy-Hb exhibits various fluctuation patterns (Toichi M. et. al, 2004). Therefore, BCI can be expected to be applied to measure

This work was supported by the Nihon University Multidisciplinary Research Grant in 2010

experiments on patients with hemiplegia to put this system into practical use.

other than the motor area (e.g., the field of entertainment).

**6. Summary** 


Hb. Conc

 (mM cm) R:Rest T:Task

tasks.

**7. Acknowledgment** 

and 2011.


**20** 

*Egypt* 

**Biopolymer Modifications** 

*1Polymer Materials Research Department, Advanced Technologies and New Materials Research Institute (ATNMRI), Mubarak City for Scientific Research and Technology Applications (MUCSAT), New Borg El-Arab City, Alexandria 2Organic Chemistry Department, Faculty of Science,* 

*Ain-Shams University, Cairo* 

**for Biomedical Applications** 

M.S. Mohy Eldin1,\*, E.A. Soliman1, A.I. Hashem2 and T.M. Tamer1

Chitosan is typically obtained by deacetylation of chitin under alkaline conditions, which is one of the most abundant organic materials, being second only to cellulose in the amount produced annually by biosynthesis. Chitosan is a linear polysaccharide, composed of glucosamine and *N*acetyl glucosamine units linked by (1–4) glycoside bonds. The content of glucosamine is called the degree of deacetylation (DD). In fact, in a general way, it is considered that when the DD of chitin is higher than about 50%(depending on the origin of the polymer and on the distribution of acetyl groups along the chains), it becomes soluble in an aqueous acidic medium, and in these conditions, it is named chitosan. The DD also affects the biodegradability of this polymer, and for DD above 69% a significant decrease of *in vivo* degradation has been found (1). Chitosan displays interesting properties such as biocompatibility, biodegradability (3, 4) and its degradation products are non-toxic, non-immunogenic and non-carcinogenic (5, 6). Therefore, chitosan has prospective applications in many fields such as biomedicine, waste water treatment, functional membranes and flocculation. However, chitosan is only soluble in few

Recently, there has been a growing interest in the chemical modification of chitosan in order to improve its solubility and widen its applications (7–9). Derivatization by introducing small functional groups to the chitosan structure, such as alkyl or carboxymethyl groups (10, 11) can drastically increase the solubility of chitosan at neutral and alkaline pH values

Substitution with moieties bearing carboxylic groups can yield polymers with polyampholytic properties (12). The antimicrobial activity of chitosan increases with decreasing pH (13-17). This is due to the fact that the amino groups of chitosan become

**1. Introduction** 

dilute acid solutions, which limits its applications.

without affecting its cationic character.

 \*

Corresponding Author

workload and increased attention," SAE International Journal of Passenger Cars - Mechanical Systems, Vol. 2 (1), pp.736-744

Toichi M., Findling RL., Kubota Y., Calabrese JR., Wiznitzer M., McNamara NK., Yamamoto K. (2004), "Hemodynamic differences in the activation of the prefrontal cortex: attention vs. higher cognitive processing," *Neuropsychologia*, Vol. 42 (5), pp. 698-706
