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Brain injury often caused irreversible loss of neural tissue and resulted in serious neurological disability. Owing to the extreme complexity of the brain, it is still challenging to regenerate the brain tissue from injury and restore its normal function. Growth factors are critical signaling molecules that promote endogenous neural stem/progenitor cells (NSPCs) proliferation, migration and differentiation, resulting in functional brain recovery from injury. However, the labile nature of growth factor motivated us to develop advanced growth factor delivery strategies to precisely control over its release profile in vivo. In this review, we will discuss growth factor delivery via biomaterials for brain regeneration after injury. This review begins with an overview of some major forms of brain injury. The characteristic properties of growth factors are described to provide a biological basis for their use in the brain regeneration. The specific biomaterials that generally used for delivering growth factor to treat brain injury are also detailed summarized. In particular, we focus on an engineering strategy that promote endogenous repair by creating growth factor concentration gradients in vivo. The last part of the review introduces current challenges and perspectives for growth factor delivery via biomaterials. [ABSTRACT FROM AUTHOR]

This study examined the association between media multitasking and executive function in Chinese adolescents by comparing heavy/high and light/low media multitaskers, i.e., HMMs and LMMs, with self-reports, behavioral measures and functional near-infrared spectroscopy (fNIRS). The participants were 12 HMMs (media multitasking scores above the 75th percentile) and 10 LMMs (media multitasking scores below the 25th percentile) chosen from a sample of 61 adolescents. Each participant completed a self-reported questionnaire on executive function and three executive function cognitive tasks: 2-back, Color Stroop, and Number-letter Determination) while wearing the fNIRS. The results indicated that: (1) the HMMs showed more impairment in executive function than the LMMs based on questionnaire data analysis; (2) there were no significant differences between the HMMs and LMMs in their performance on the cognitive tasks; and (3) the HMMs showed greater prefrontal activation than the LMMs during the 2-back and Color Stroop tasks. These findings implied that media multitasking might be associated with the reduced effectiveness in the brain areas responsible for executive function. These findings provide evidence of the negative relationship between media multitasking and executive function; and indicated the benefits of using multiple assessment methods in studying this topic. [ABSTRACT FROM AUTHOR]

Sparse Bayesian learning (SBL) has given renewed interest to the problem of direction-of-arrival (DOA) estimation. It is generally assumed that the measurement matrix in SBL is precisely known. Unfortunately, this assumption may be invalid in practice due to the imperfect manifold caused by unknown or misspecified mutual coupling. This paper describes a modified SBL method for joint estimation of DOAs and mutual coupling coefficients with uniform linear arrays (ULAs). Unlike the existing method that only uses stationary priors, our new approach utilizes a hierarchical form of the Student t prior to enforce the sparsity of the unknown signal more heavily. We also provide a distinct Bayesian inference for the expectation-maximization (EM) algorithm, which can update the mutual coupling coefficients more efficiently. Another difference is that our method uses an additional singular value decomposition (SVD) to reduce the computational complexity of the signal reconstruction process and the sensitivity to the measurement noise. [ABSTRACT FROM AUTHOR]