Sizing nanomatter in biological fluids by fluorescence single particle tracking

Accurate sizing of nanoparticles in biological media is important for drug delivery and biomedical imaging applications since size directly influences the nanoparticle processing and nanotoxicity in vivo. Using fluorescence single particle cracking we have succeeded for the first time in following the aggregation of drug delivery nanoparticles in real time in undiluted whole blood. We demonstrate that, by using a suitable surface functionalization, nanoparticle aggregation in the blood circulation is prevented to a large extent

Fluorescence single particle tracking for sizing of nanoparticles in undiluted biological fluids

While extremely relevant to many life science fields, such as biomedical diagnostics and drug delivery, studies on the size of nanoparticulate matter dispersed in biofluids are missing due to a lack of suitable methods. Here we report that fluorescence single particle tracking (fSPT) with maximum entropy analysis is the first technique suited for accurate sizing of nanoparticles dispersed in biofluids, such as whole blood. After a thorough validation, the fSPT sizing method was applied to liposomes that have been under investigation for decades as nanocarriers for drugs. The tendency of these liposomes to form aggregates in whole blood was tested in vitro and in vivo. In addition, we have demonstrated that the fSPT sizing technique can be used for identifying and sizing natural cell-derived microparticles directly in plasma. fSPT sizing opens up the possibility to systematically study the size and aggregation of endogenous or exogenous nanoparticles in biofluids

Music pre-processing for cochlear implants

A Cochlear Implant (CI) is a medical device that enables profoundly hearing impaired people to perceive sounds by electrically stimulating the auditory nerve using an electrode array implanted in the cochlea. The focus of most research on signal processing for CIs has been on strategies to improve speech understanding in quiet and in background noise, since the main aim for implanting a CInbsp;(and still is) to restore the ability to communicate. Most CI users perform quite well in terms of speech understanding. On the other hand, music perception and appreciation are generally very poor. The main goal of this PhD project was to investigate and to improve the poor music enjoyment in CI users. An initial experiment with multi-track recordings was carried out to examine the music mixing preferences for different instruments in polyphonic or complex music. In general, a preference for clear vocals and attenuated instruments was observed with preservation of bass and drums. Based on this knowledge, a music pre-processing scheme for mono and stereo recordings wasnbsp;which is capable of balancing vocals/bass/drums against the other instruments. The scheme is based on thenbsp;of harmonic and percussive components in the spectrogram and on the spatial information of the instruments in typical stereo recordings. Subsequently, the music pre-processing scheme was evaluated in a take-home experiment with post-lingually deafened CI users andnbsp;genres of music, providing encouraging results for building a tool for music training or rehabilitation programs.Acknowledgement 3 Abstract 6 Abstract (Dutch translation) 8 List of acronyms and abbreviations 10 Table of Contents 15 List of figures 19 List of tables 23 Chapter 1 : Introduction 25 1.1 The human auditory system 25 1.1.1 Anatomy of the human ear 25 1.1.2 Hearing loss 27 1.2 Cochlear implants 28 1.2.1 The CI system 28 1.2.2 Sound processing in CI 30 1.2.3 Performance of CI users 35 1.3 Cochlear implants and music 36 1.3.1 Music perception with CI 37 1.3.2 Music appreciation with CI 41 1.4 The music signal 42 1.4.1 Music complexity 43 1.4.2 Sound source separation techniques 43 1.5 Motivation 45 1.6 Objectives and outline 46 Chapter 2 : Music mixing preferences of cochlear implant recipients: a pilot study 51 2.1 Abstract 51 2.2 Introduction 52 2.3 Methods 56 2.3.1 Sound material 56 2.3.2 Subjects 58 2.3.3 Experiment 1 60 2.3.4 Experiment 2 61 2.3.5 Statistics 64 2.4 Results 65 2.4.1 Experiment 1 65 2.4.2 Experiment 2 68 2.5 Discussion 74 2.6 Conclusion 78 Chapter 3 : A Harmonic/Percussive Sound Separation based Music Pre-Processing Scheme for Cochlear Implant Users 79 3.1 Abstract 79 3.2 Introduction 80 3.3 Music pre-processing scheme 82 3.4 Objective testing 86 3.5 Subjective testing 90 3.6 Conclusion 92 Chapter 4 : A stereo music pre-processing scheme for cochlear implant users 93 4.1 Abstract 93 4.2 Introduction 94 4.3 Stereo music pre-processing scheme 98 4.3.1 Vocals & Drums Extraction 99 4.3.2 Bass frequency extraction 107 4.3.3 Stereo binary mask 108 4.3.4 Stereo music pre-processing output 113 4.4 Methods 113 4.4.1 Sound material 114 4.4.2 Subjects 115 4.4.3 Perceptual evaluation 116 4.5 Results 117 4.6 Discussion 119 4.7 Conclusion 123 Chapter 5 : Evaluation of stereo music pre-processing for cochlear implant users 125 5.1 Abstract 125 5.2 Introduction 126 5.3 Methods 129 5.3.1 Sound material 129 5.3.2 Subjects 130 5.3.3 Take-home device 131 5.3.4 Test procedure 133 5.4 Results 135 5.5 Discussion 140 5.6 Conclusion 143 Chapter 6 : Conclusions and future work 145 6.1 Music mixing preference experiment 146 6.2 Music pre-processing scheme 147 6.3 Take-home evaluation 148 6.4 Future work 149 6.4.1 Music feature preference 150 6.4.2 Advanced music pre-processing 151 6.4.3 Fitting a music map 152 Appendix 153 Bibliography 171 Curriculum Vitae 184 List of publications 185nrpages: 187status: publishe

A stereo music pre-processing scheme for cochlear implant users

OBJECTIVE: Listening to music is still one of the more challenging aspects of using a cochlear implant (CI) for most users. Simple musical structures, a clear rhythm/beat, and lyrics that are easy to follow are among the top factors contributing to music appreciation for CI users. Modifying the audio mix of complex music potentially improves music enjoyment in CI users. METHODS: A stereo music preprocessing scheme is described in which vocals, drums, and bass are emphasized based on the representation of the harmonic and the percussive components in the input spectrogram, combined with the spatial allocation of instruments in typical stereo recordings. The scheme is assessed with postlingually deafened CI subjects (N = 7) using pop/rock music excerpts with different complexity levels. RESULTS: The scheme is capable of modifying relative instrument level settings, with the aim of improving music appreciation in CI users, and allows individual preference adjustments. The assessment with CI subjects confirms the preference for more emphasis on vocals, drums, and bass as offered by the preprocessing scheme, especially for songs with higher complexity. CONCLUSION: The stereo music preprocessing scheme has the potential to improve music enjoyment in CI users by modifying the audio mix in widespread (stereo) music recordings. SIGNIFICANCE: Since music enjoyment in CI users is generally poor, this scheme can assist the music listening experience of CI users as a training or rehabilitation tool.status: publishe

Take-home evaluation of music pre-processing scheme with cochlear implant users

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Clinical take-home evaluation of music pre-processing scheme for cochlear implant users

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Evaluation of stereo music pre-processing for cochlear implant users

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