Speakers for Feb. 7 Graduate Student Seminar Announced

Three Ph.D. students will discuss their research at the Beckman Institute’s first spring Graduate Student Seminar at noon Wednesday, Feb. 7, in Room 1005. The presenters: Svyatoslav Dvoretskiy, a Ph.D. student in the Bioimaging Science and Technology Group; Hassaan Majeed, a Beckman Institute Graduate Fellow in the Bioimaging Science and Technology Group; and Timothy P. Moneypenny II, a Beckman Institute Graduate Fellow in the Molecular and Electronic Nanostructures research theme. Lunch will be provided.

“Pericyte Response to Muscle Contraction”

Svyatoslav Dvoretskiy, Ph.D. student in kinesiology, Bioimaging Science and Technology Group

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Injury and illness may require a period of immobilization that may be localized to a single limb (casting) or to the whole body (bed rest). Immobilization is necessary for healing of a fracture or recovery from an illness, but it can result in a rapid and significant loss of skeletal muscle mass and function. Recovery may be slow and long-term disability is a potential outcome, especially in diseased or aged adults. Pericytes are vascular supportive cells that incompletely encase endothelial cells and form connections with adjacent capillary endothelial cells which provide important structural and paracrine support to regulate vascular permeability, vessel diameter and blood flow, and stabilization of newly formed capillaries. The purpose of this study was to isolate and directly compare the response of pericytes (NG2+ and CD146+) to a mechanical stimulus both in vivo and in vitro. Our results suggest that CD146+ pericytes have a more favorable gene expression profile for transplantation therapy based on the significant upregulation of myogenic growth factor and extracellular matrix remodeling genes. We have transplanted CD146+ pericytes into mouse hindlimbs following a period of immobilization and demonstrated a significant recovery following reload in the cell injected group compared to the saline.

“Label-free Quantitative Histopathology of Breast Tissue Using Quantitative Phase Imaging”

Hassaan Majeed, Ph.D. student in bioengineering, Bioimaging Science and Technology Group

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According to the World Health Organization (WHO), breast cancer is the most prevalent form of cancer among women in both the developed and developing world. The standard method for breast histopathology relies on manual microscopic examination of stained tissue morphology by a pathologist. This standard method suffers from inter-observer variation and low-throughput due to qualitative and manual assessment. In this work, we use quantitative phase imaging (QPI), a quantitative microscopy method, to evaluate breast tissue biopsies based on their optical path-length difference (OPD) maps. By relying on scattering, geometric and texture-based features extracted from these OPD maps, we developed a supervised classification scheme for separating benign and malignant cases within a tissue microarray. We measured a classification AUC of 0.91 for separating cancer from non-cancer. We further demonstrate that our classification method is invariant to tissue staining. This development is important because tissue biopsies are routinely stained by pathologists during investigation and thus stain invariant tissue evaluation methods allow for easier clinical adoption. Our method can, thus, address the shortcomings of standard tissue evaluation by relying on quantitative disease markers. These markers can also potentially provide additional information to pathologists during differential diagnosis.

“Lithium Electrolyte Nanocomposites Derived From Porous Molecular Cages”

Timothy P. Moneypenny II, Ph.D. student in chemistry, Molecular and Electronic Nanostructures research theme

Molecular porous materials enable efficient lithium ion transport.

Lithium ion batteries represent a significant technological advancement in energy storage and are widely prevalent in modern portable devices such as cellphones, computers, and digital cameras. Their high energy density and operating potential offer unique advantages over antiquated nickel cadmium counterparts including longer battery life, reduced charging times, and higher temperature stability. However, they suffer from substantial practical limitations that restrict their capacity to power much larger equipment. In reality, the long-standing challenge for lithium ion battery research resides in the safety concerns related to conventional organic liquid electrolytes that are used for lithium ion transport. The use of a liquid electrolyte poses the threat of potential leakage of corrosive and flammable liquids. Consequently, it is not uncommon for malfunctioning lithium ion batteries to explode or cause fires. To remedy these inherent problems, there is much interest in synthesizing solid-state electrolytes which mitigate safety concerns but also allow efficient lithium ion transport. Herein, we test the hypothesis that a nanocomposite fabricated from a porous molecular cage is an effective solid-state lithium electrolyte. Our results support this hypothesis and demonstrate that this material is a solid-state lithium electrolyte nanocomposite (SLEN). This system enables the rational design of electrolytes from tunable discrete molecular architectures.