Designing non-Hermitian real spectra through electrostatics.

Non-hermiticity presents a vast newly opened territory that harbors new physics and applications such as lasing and sensing. However, only non-Hermitian systems with real eigenenergies are stable, and great efforts have been devoted in designing them through enforcing parity-time (PT) symmetry. In this work, we exploit a lesser-known dynamical mechanism for enforcing real-spectra, and develop a comprehensive and versatile approach for designing new classes of parent Hamiltonians with real spectra. Our design approach is based on a new electrostatics analogy for modified non-Hermitian bulk-boundary correspondence, where electrostatic charge corresponds to density of states and electric fields correspond to complex spectral flow. As such, Hamiltonians of any desired spectra and state localization profile can be reverse-engineered, particularly those without any guiding symmetry principles. By recasting the diagonalization of non-Hermitian Hamiltonians as a Poisson boundary value problem, our electrostatics analogy also transcends the gain/loss-induced compounding of floating-point errors in traditional numerical methods, thereby allowing access to far larger system sizes.

"Cut-and-Paste" Manufacture of Multiparametric Epidermal Sensor Systems.

Multifunctional epidermal sensor systems (ESS) are manufactured with a highly cost and time effective, benchtop, and large-area "cut-and-paste" method. The ESS made out of thin and stretchable metal and conductive polymer ribbons can be noninvasively laminated onto the skin surface to sense electrophysiological signals, skin temperature, skin hydration, and respiratory rate.

Therapeutic potential of human adipose stem cells in a cancer stem cell-like gastric cancer cell model.

Cancer stem cells (CSCs) or circulating tumor cells play an important role in tumor initiation, invasion, metastasis and resistance to anticancer therapies. Therapies that target gastric tumor CSCs have potential clinical application for preventing malignant gastric tumor progression and metastasis. We isolated CD44+ gastric cancer cells from the gastric cancer cell line AGS and Hs746T cells and maintained the cells in a novel stem cell culture. The cells were kept in an undifferentiated proliferative state and we characterized their cancer stem cell properties and chemotherapy-resistance behavior. The CD44+ cancer cells were also co-cultured with human adipose stem cells (ADSCs) to determine the chemotherapy-promotion effects of the adipose cells on the CD44+ cancer cells. The CD44+ gastric cancer cell model is a non-adhesion, 3-dimensional, spheroid phenotype. The non-adherent CD44+ cells have cancer stem cell properties and are highly chemo-resistant. However, these cells regained chemo-sensitivity when re-attached to an extracellular matrix-coated attachment surface. The human adipose stem cells significantly promoted the chemo-sensitivity of the non-adherent CD44+ gastric cancer cells. Integrin α2/ß2 and the Wnt signaling pathways are involved in the mechanisms. We concluded that the in vitro non-adherent CD44+ gastric cancer cell model resembles the circulating gastric tumor cells in vivo. Introduction of an appropriate attachment surface significantly promotes chemo-sensitivity of the non-adherent CD44+ gastric cancer cells. The human adipose stem cells function as a 'living vehicle surface' for such a purpose in vivo.

Diagnostic and therapeutic options in the management of nonvariceal upper gastrointestinal bleeding.

Upper gastrointestinal bleeding from peptic ulcers is common. Advances in prognostication, therapeutic endoscopy, and medical management have evolved rapidly. Patients most likely to rebleed after therapy can now be identified and monitored more closely, and patients with ulcers of low risk for rebleeding can be managed on an outpatient basis. High-risk patients include those with ulcers containing a visible vessel or who are actively bleeding. Endoscopic therapy is mandatory in high-risk patients and involves at least two hemostatic techniques. Second-look endoscopy and repeated hemostasis should be performed promptly in patients who rebleed. Adjunctive treatment includes intravenous proton pump inhibitor administered in high doses for the first 72 hours after endoscopic therapy. Further studies are needed to determine the optimal combination of hemostatic techniques to better target patients who are at risk for ulcer rebleeding.