Imaging fiber orientation in articular cartilage using optical polarization tractography

Articular cartilage plays a vital role in providing a low-friction surface between the bones of joints. This mechanical function is highly related to the special collagen organization in cartilage, especially in the superficial zone. The "split-line" method has been previously used to examine the fiber orientation in superficial zone of the cartilage. Because the "split-lines" are created by pricking the cartilage surface using a needle, this method is destructive and cannot be used for diagnosis purpose. In this thesis research, I applied optical polarization tractography (OPT) to visualize fiber orientation in cartilage. OPT is a recently developed high resolution imaging technology based on polarization-sensitive optical coherence tomography. OPT has been previously applied to visualize fiber structures in muscles. We showed that OPT can non-destructively image the fiber orientation in cartilage. The orientation obtained in OPT agreed very well with the split-line results. In addition, the thickness of cartilage and the thickness of superficial zone can be obtained in OPT results. These findings show that OPT has a great potential in clinical orthopedic applications

Generalized S1S^1-stability theorem

We use the equivariant $\mu$-bubbles technique to prove that for any compact manifold $M^n$ with non-empty boundary, $n\in\{3,5,6\}$, the Yamabe invariant of $M^n$ is positive if and only if the Yamabe invariant of $M^n\times S^1$ is positive. This generalized the $S^1$-stability conjecture of Rosenberg to compact manifolds with boundary.Comment: 14 pages, comments are welcome

Monotone Quantities for pp-Harmonic functions and the Sharp pp-Penrose inequality

Consider a complete asymptotically flat 3-manifold $M$ with non-negative scalar curvature and non-empty minimal boundary $\Sigma$. Fix a number $1 < p < 2$. We derive monotone quantities for $p$-harmonic functions on $M$ which become constant on Schwarzschild. These monotonicity formulas imply a sharp mass-capacity estimate relating the ADM mass of $M$ with the $p$-capacity of $\Sigma$ in $M$, which was first proved by Xiao using weak inverse mean curvature flow.Comment: 20 pages, comments are welcome

Improved Hebey-Vaugon conjecture on equivariant Yamabe invariants in dimension 3

Consider a closed connected $3$-manifold $M$ acted diffeomorphically on by a compact Lie group $G$ with at least one orbit of finite cardinality. We show an upper bound for the $G$-equivariant Yamabe invariant $\sigma_G(M)$ under certain topological assumptions, which improved a conjecture of Hebey-Vaugon.Comment: 10 pages, 2 figures, comments are welcome

Local anaesthetic bupivacaine induced ovarian and prostate cancer apoptotic cell death and underlying mechanisms in vitro

Retrospective studies indicate that the use of regional anesthesia can reduce cancer recurrence after surgery which could be due to ranging from immune function preservation to direct molecular mechanisms. This study was to investigate the effects of bupivacaine on ovarian and prostate cancer cell biology and the underlying molecular mechanisms. Cell viability, proliferation and migration of ovarian carcinoma (SKOV-3) and prostate carcinoma (PC-3) were examined following treatment with bupivacaine. Cleaved caspase 3, 8 and 9, and GSK-3β, pGSK-3β(tyr216) and pGSK-3β(ser9) expression were assessed by immunofluorescence. FAS ligand neutralization, caspase and GSK-3 inhibitors and GSK-3β siRNA were applied to further explore underlying mechanisms. Clinically relevant concentrations of bupivacaine reduced cell viability and inhibited cellular proliferation and migration in both cell lines. Caspase 8 and 9 inhibition generated partial cell death reversal in SKOV-3, whilst only caspase 9 was effective in PC-3. Bupivacaine increased the phosphorylation of GSK-3β(Tyr216) in SKOV-3 but without measurable effect in PC3. GSK-3β inhibition and siRNA gene knockdown decreased bupivacaine induced cell death in SKOV-3 but not in PC3. Our data suggests that bupivacaine has direct ‘anti-cancer’ properties through the activation of intrinsic and extrinsic apoptotic pathways in ovarian cancer but only the intrinsic pathway in prostate cancer

Optical Non-Reciprocity in Coupled Resonators Inspired by Photosynthetic Energy Transfer

Inspired by the photosynthetic energy transfer process, we theoretically propose a method to realize non-reciprocal optical transmission in an array of coupled resonators. The optical non-reciprocity of the coupled resonators arises from the frequency gradient between adjacent cavities and the interaction with the environment, which is similar to photosynthetic energy transfer. An increase in the frequency gradient or the number of the cavities can lead to better non-reciprocity. However, although a higher environment temperature will increase the total photon number in the coupled cavities, non-reciprocity will be weakened. All these findings can be well described by the detailed balance. Our discovery reveals the similarity between the noise-induced optical non-reciprocity and exciton energy transfer in natural photosynthesis.Comment: 6 pages, 8 figure