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Christine Ho

Bio: Christine Ho is an academic researcher from University of California, Berkeley. The author has contributed to research in topics: Energy storage & Energy harvesting. The author has an hindex of 14, co-authored 34 publications receiving 1085 citations. Previous affiliations of Christine Ho include University of California, San Francisco & University of California.

Papers
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Journal ArticleDOI
TL;DR: This work integrates DNA sequence and copy number information to reconstruct the order of abnormalities as individual tumors evolve for 2 separate cancer types, and reframe paradigms in which TP53 mutation is required later, to bypass senescence induced by driver oncogenes.
Abstract: Timely intervention for cancer requires knowledge of its earliest genetic aberrations. Sequencing of tumors and their metastases reveals numerous abnormalities occurring late in progression. A means to temporally order aberrations in a single cancer, rather than inferring them from serially acquired samples, would define changes preceding even clinically evident disease. We integrate DNA sequence and copy number information to reconstruct the order of abnormalities as individual tumors evolve for 2 separate cancer types. We detect vast, unreported expansion of simple mutations sharply demarcated by recombinative loss of the second copy of TP53 in cutaneous squamous cell carcinomas (cSCC) and serous ovarian adenocarcinomas, in the former surpassing 50 mutations per megabase. In cSCCs, we also report diverse secondary mutations in known and novel oncogenic pathways, illustrating how such expanded mutagenesis directly promotes malignant progression. These results reframe paradigms in which TP53 mutation is required later, to bypass senescence induced by driver oncogenes.

252 citations

Proceedings ArticleDOI
21 May 2007
TL;DR: The goal of the work is to focus on health-related applications of wireless sensor networks and how current (and future) technologies will enable automated home health monitoring.
Abstract: Sophisticated electronics are within reach of average users. Cooperation between wireless sensor networks and existing consumer electronic infrastructures can assist in the areas of health care and patient monitoring. This will improve the quality of life of patients, provide early detection for certain ailments, and improve doctor-patient efficiency. The goal of our work is to focus on health-related applications of wireless sensor networks. In this paper we detail our experiences building several prototypes and discuss the driving force behind home health monitoring and how current (and future) technologies will enable automated home health monitoring.

200 citations

Journal ArticleDOI
TL;DR: In this article, a direct write dispenser printing method was developed to fabricate multilayer structures and precisely deposit and pattern these components onto any substrates, enabling the simple fabrication of stacked microbattery structures with the potential to be easily integrated directly onto a microdevice substrate.
Abstract: The need for energy dense microbatteries with miniature dimensions has prompted the development of unconventional materials, cell geometries, and processing methods. This work will highlight our materials investigations, deposition methods and the device performance of a printed zinc–manganese dioxide rechargeable microbattery utilizing an ionic liquid gel electrolyte. We have developed a direct write dispenser printing method with the ability to fabricate multilayer structures and precisely deposit and pattern these components onto any substrates. The use of a unique room-temperature ionic liquid swelled into a polymer to form a gel electrolyte with solid-like mechanical strength and liquid-like ion transport properties has enabled the simple fabrication of stacked microbattery structures with the potential to be easily integrated directly onto a microdevice substrate. Initial microbattery tests and cycle behavior are discussed, and after an initial activation of the cathode material, an experimental cell discharge capacity and energy density of 0.98 mA h cm−2 and 1.2 mW h cm−2 were measured, respectively.

137 citations

Journal ArticleDOI
TL;DR: In this article, a super ink jet printing (SIJP) system was used to fabricate 3D zinc-silver microbatteries directly on a substrate, which showed similar electrochemical behavior to batteries composed of silver foil electrodes.
Abstract: A novel super ink jet printing (SIJP) system was used to fabricate 3D zinc–silver microbatteries directly on a substrate. The SIJP provides a simple and flexible method to deposit interesting 2D and 3D structures of varying morphologies without the waste and large energy inputs typical of standard microfabrication technologies. The system was used to print pairs of silver electrodes with arrays of pillars on glass substrates, and in the presence of an electrolyte, the battery self-assembled during the first charge. Using an aqueous electrolyte solution of KOH with dissolved ZnO, the SIJP printed structures showed similar electrochemical behavior to batteries composed of silver foil electrodes. For a sparse array of pillars (~2.5% footprint area of each electrode pad occupied by pillars), a capacity increase of 60% was achieved in comparison with a cell with planar electrodes.

124 citations

Journal ArticleDOI
19 May 2015
TL;DR: In this article, a review of key requirements for energy storage for high functionality flexible electronics prototype systems and some approaches that have been explored to meet those needs is presented, with the conclusion that safe, low cost, flexible electronics energy storage requirements may be most appropriately met using intrinsically stable battery chemistry.
Abstract: If truly thin embedded and human worn flexible electronics are to become a commercial reality for wearable electronics, medical devices, and internet of things tags, effective energy storage technologies that safely and robustly match the mechanical flexibility of the overall system form factor are required. At the same time, the energy and transient power needs of functions such as wireless connectivity, information display, and high sample rate sensing must be supported. These capabilities have time-dependent power and current requirements often not captured in simple energy and capacity metrics. In this paper, a progression of energy storage approaches, challenges and learning experiences will be presented from the perspective of an energy storage technology developer. The essential requirements for energy storage for feature-driven applications in flexible electronics are addressed with the goal of finding the most compelling fit between products needs, consumer safety and the technology capabilities of different energy storage approaches. Micropower modules from supercapacitors to microbatteries and their limitations for flexible electronics will be discussed in terms of capacity, power and charge retention as the starting point. Following this discussion, limitations of lithium technologies in this flexible and thin ( $ 1 mm) application space are also outlined. This paper then presents a review of key requirements for energy storage for high functionality flexible electronics prototype systems and some approaches that have been explored to meet those needs. This leads to the conclusion that safe, low cost, flexible electronics energy storage requirements may be most appropriately met using intrinsically stable battery chemistry. Furthermore, such a materials approach allows for simpler lower cost processing and packaging, such as additive printing and roll to roll processing of thin and therefore more mechanically flexible cells. Examples and performance data from such a zinc polymer battery technology are given and compared to other thin and flexible battery approaches.

70 citations


Cited by
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Journal ArticleDOI
TL;DR: This survey presents a comprehensive review of the recent literature since the publication of a survey on sensor networks, and gives an overview of several new applications and then reviews the literature on various aspects of WSNs.

5,626 citations

Journal ArticleDOI
TL;DR: The MuTect algorithm for calling somatic point mutations enables subclonal analysis of the whole-genome or whole-exome sequencing data being generated in large-scale cancer genomics projects as discussed by the authors.
Abstract: The MuTect algorithm for calling somatic point mutations enables subclonal analysis of the whole-genome or whole-exome sequencing data being generated in large-scale cancer genomics projects.

3,773 citations

01 Feb 2013
TL;DR: MuTect is presented, a method that applies a Bayesian classifier to detect somatic mutations with very low allele fractions, requiring only a few supporting reads, followed by carefully tuned filters that ensure high specificity.

2,665 citations

Journal ArticleDOI
19 Jan 2012-Nature
TL;DR: The inherently Darwinian character of cancer is the primary reason for this therapeutic failure, but it may also hold the key to more effective control.
Abstract: Cancers evolve by a reiterative process of clonal expansion, genetic diversification and clonal selection within the adaptive landscapes of tissue ecosystems. The dynamics are complex, with highly variable patterns of genetic diversity and resulting clonal architecture. Therapeutic intervention may destroy cancer clones and erode their habitats, but it can also inadvertently provide a potent selective pressure for the expansion of resistant variants. The inherently Darwinian character of cancer is the primary reason for this therapeutic failure, but it may also hold the key to more effective control.

2,575 citations

01 Nov 2000
TL;DR: In this paper, the authors compared the power density characteristics of ultracapacitors and batteries with respect to the same charge/discharge efficiency, and showed that the battery can achieve energy densities of 10 Wh/kg or higher with a power density of 1.2 kW/kg.
Abstract: The science and technology of ultracapacitors are reviewed for a number of electrode materials, including carbon, mixed metal oxides, and conducting polymers. More work has been done using microporous carbons than with the other materials and most of the commercially available devices use carbon electrodes and an organic electrolytes. The energy density of these devices is 3¯5 Wh/kg with a power density of 300¯500 W/kg for high efficiency (90¯95%) charge/discharges. Projections of future developments using carbon indicate that energy densities of 10 Wh/kg or higher are likely with power densities of 1¯2 kW/kg. A key problem in the fabrication of these advanced devices is the bonding of the thin electrodes to a current collector such the contact resistance is less than 0.1 cm2. Special attention is given in the paper to comparing the power density characteristics of ultracapacitors and batteries. The comparisons should be made at the same charge/discharge efficiency.

2,437 citations