Integrating Symmetry into Differentiable Planning with Steerable Convolutions

We study how group symmetry helps improve data efficiency and generalization for end-to-end differentiable planning algorithms when symmetry appears in decision-making tasks. Motivated by equivariant convolution networks, we treat the path planning problem as \textit{signals} over grids. We show that value iteration in this case is a linear equivariant operator, which is a (steerable) convolution. This extends Value Iteration Networks (VINs) on using convolutional networks for path planning with additional rotation and reflection symmetry. Our implementation is based on VINs and uses steerable convolution networks to incorporate symmetry. The experiments are performed on four tasks: 2D navigation, visual navigation, and 2 degrees of freedom (2DOFs) configuration space and workspace manipulation. Our symmetric planning algorithms improve training efficiency and generalization by large margins compared to non-equivariant counterparts, VIN and GPPN.Comment: Restructured main text and appendix. Renamed from "Integrating Symmetry into Differentiable Planning

p21-Activated Kinases 1, 2 and 4 in Endometrial Cancers: Effects on Clinical Outcomes and Cell Proliferation

p21-activated kinases (Paks) are serine/threonine protein kinases involved in biological events linked to malignant tumor progression. In this study, expression of Pak1, p-Pak2 Ser20, Pak4, pPak4 Ser474 in 21 normal endometrium, 16 hyperplastic endometrium without atypia, 17 atypical complex hyperplasia and 67 endometrial cancers was assessed by immunohistochemistry and correlated with clinicopathological parameters. We also accessed the proliferative role and downstream targets of Pak1 in endometrial cancer. Pak1 was expressed in cytoplasm whereas Pak4 and p-Pak4 were expressed in both cytoplasm and nucleus of endometrial tissues. In normal endometrium, significantly higher Pak1 (P = 0.028) and cytoplasmic p-Pak2 (P = 0.048) expression was detected in proliferative endometrium than secretory endometrium. Pak1, cytoplasmic and nuclear Pak4 and nuclear p-Pak4 was significantly overexpressed in endometrial cancer when compared to atrophic endometrium (all P<0.05). Moreover, type I endometrioid carcinomas showed significantly higher Pak1 expression than type II non-endometrioid carcinomas (P<0.001). On the other hand, Pak1, Pak4 and p-Pak4 expression negatively correlated with histological grade (all P<0.05) while p-Pak2 and cytoplasmic Pak4 expression inversely correlated with myometrial invasion (all P<0.05). Furthermore, patients with endometrial cancers with lower cytoplasmic Pak4 expression showed poorer survival (P = 0.026). Multivariate analysis showed cytoplasmic Pak4 is an independent prognostic factor. Functionally, knockdown of Pak1, but not Pak4, in endometrial cancer cell line led to reduced cell proliferation along with reduced cyclin D1, estrogen receptor (ERα) and progestogen receptor (PR) expression. Significant correlation between Pak1 and PR expression was also detected in clinical samples. Our findings suggest that Pak1 and cytoplasmic p-Pak2 may promote cell proliferation in normal endometrium during menstral cycle. Pak1, cytoplasmic and nuclear Pak4 and nuclear p-Pak4 are involved in the pathogenesis of endometrial cancer especially in postmenopausal women. Pak1 promote endometrial cancer cell proliferation, particular in type I endometrioid carcinoma. Cytoplasmic Pak4 can be potential prognostic marker in endometrial cancer.published_or_final_versio

Transcriptome-Guided Functional Analyses Reveal Novel Biological Properties and Regulatory Hierarchy of Human Embryonic Stem Cell-Derived Ventricular Cardiomyocytes Crucial for Maturation

Human (h) embryonic stem cells (ESC) represent an unlimited source of cardiomyocytes (CMs); however, these differentiated cells are immature. Thus far, gene profiling studies have been performed with non-purified or non-chamber specific CMs. Here we took a combinatorial approach of using systems biology to guide functional discoveries of novel biological properties of purified hESC-derived ventricular (V) CMs. We profiled the transcriptomes of hESCs, hESC-, fetal (hF) and adult (hA) VCMs, and showed that hESC-VCMs displayed a unique transcriptomic signature. Not only did a detailed comparison between hESC-VCMs and hF-VCMs confirm known expression changes in metabolic and contractile genes, it further revealed novel differences in genes associated with reactive oxygen species (ROS) metabolism, migration and cell cycle, as well as potassium and calcium ion transport. Following these guides, we functionally confirmed that hESC-VCMs expressed IKATP with immature properties, and were accordingly vulnerable to hypoxia/reoxygenation-induced apoptosis. For mechanistic insights, our coexpression and promoter analyses uncovered a novel transcriptional hierarchy involving select transcription factors (GATA4, HAND1, NKX2.5, PPARGC1A and TCF8), and genes involved in contraction, calcium homeostasis and metabolism. These data highlight novel expression and functional differences between hESC-VCMs and their fetal counterparts, and offer insights into the underlying cell developmental state. These findings may lead to mechanism-based methods for in vitro driven maturation. © 2013 Poon et al.published_or_final_versio

Identification and Expression Profiling of MicroRNAs in the Brain, Liver and Gonads of Marine Medaka (Oryzias melastigma) and in Response to Hypoxia

The marine medaka (Oryzias melastigma) has been increasingly used as a fish model for detecting environmental stresses and chemical contaminants in the marine environment. Recent mammalian studies have shown that environmental stresses can alter the expression profiles of microRNAs (miRNAs), leading to transgenerational effects. Here, we use high-throughput Illumina RNA sequencing (RNA-Seq) for miRNA transcriptome analysis of brain, liver, and gonads from sexually mature male and female marine medaka. A total of 128,883,806 filtered sequence reads were generated from six small RNA libraries, identifying a total of 2,125,663 non-redundant sequences. These sequences were aligned and annotated to known animal miRNAs (miRBase) using the BLAST method. A total of 223 distinct miRNA types were identified, with the greatest number expressed in brain tissue. Our data suggested that 55 miRNA types from 34 families are common to all tested tissues, while some of the miRNAs are tissue-enriched or sex-enriched. Quantitative real-time PCR analysis further demonstrated that let-7a, miR-122, and miR-9-3p were downregulated in hypoxic female medaka, while miR-2184 was specifically upregulated in the testis of hypoxic male fish. This is the first study to identify miRNAs in O. melastigma using small RNA deep sequencing technology. Because miRNA expression is highly conserved between marine medaka and other vertebrates, marine medaka may serve as a good model for studies on the functional roles of miRNAs in hypoxia stress response and signaling in marine fish.published_or_final_versio

Electrodynamics of Media

Contains reports on six research projects.Joint Services Electronics Program (Contract DAABO7-71-C-0300)U. S. Army Research Office - Durham (Contract DAHC04-72-C-0044)National Science Foundation (Grant GK-31012X), Cornell Universit

High-contrast, fast chemical imaging by coherent Raman scattering using a self-synchronized two-colour fibre laser

Kong C, Pilger C, Hachmeister H, et al. High-contrast, fast chemical imaging by coherent Raman scattering using a self-synchronized two-colour fibre laser. Light: Science &amp; Applications. 2020;9(1): 25.Coherent Raman scattering (CRS) microscopy is widely recognized as a powerful tool for tackling biomedical problems based on its chemically specific label-free contrast, high spatial and spectral resolution, and high sensitivity. However, the clinical translation of CRS imaging technologies has long been hindered by traditional solid-state lasers with environmentally sensitive operations and large footprints. Ultrafast fibre lasers can potentially overcome these shortcomings but have not yet been fully exploited for CRS imaging, as previous implementations have suffered from high intensity noise, a narrow tuning range and low power, resulting in low image qualities and slow imaging speeds. Here, we present a novel high-power self-synchronized two-colour pulsed fibre laser that achieves excellent performance in terms of intensity stability (improved by 50 dB), timing jitter (24.3 fs), average power fluctuation (20 dB) and pulse width variation (<1.8%) over an extended wavenumber range (2700–3550 cm−1). The versatility of the laser source enables, for the first time, high-contrast, fast CRS imaging without complicated noise reduction via balanced detection schemes. These capabilities are demonstrated in this work by imaging a wide range of species such as living human cells and mouse arterial tissues and performing multimodal nonlinear imaging of mouse tail, kidney and brain tissue sections by utilizing second-harmonic generation and two-photon excited fluorescence, which provides multiple optical contrast mechanisms simultaneously and maximizes the gathered information content for biological visualization and medical diagnosis. This work also establishes a general scenario for remodelling existing lasers into synchronized two-colour lasers and thus promotes a wider popularization and application of CRS imaging technologies

RBMS3 at 3p24 inhibits nasopharyngeal carcinoma development via inhibiting cell proliferation, angiogenesis, and inducing apoptosis.

Deletion of the short arm of chromosome 3 is one of the most frequent genetic alterations in many solid tumors including nasopharyngeal carcinoma (NPC), suggesting the existence of one or more tumor suppressor genes (TSGs) within the frequently deleted region. A putative TSG RBMS3 (RNA binding motif, single stranded interacting protein 3), located at 3p24-p23, has been identified in our previous study. Here, we reported that downregulation of RBMS3 was detected in 3/3 NPC cell lines and 13/15 (86.7%) primary NPC tissues. Functional studies using both overexpression and suppression systems demonstrated that RBMS3 has a strong tumor suppressive role in NPC. The tumor suppressive mechanism of RBMS3 was associated with its role in cell cycle arrest at the G1/S checkpoint by upregulating p53 and p21, downregulating cyclin E and CDK2, and the subsequent inhibition of Rb-ser780. Further analysis demonstrated that RBMS3 had a pro-apoptotic role in a mitochondrial-dependent manner via activation of caspase-9 and PARP. Finally, RBMS3 inhibited microvessel formation, which may be mediated by down-regulation of MMP2 and β-catenin and inactivation of its downstream targets, including cyclin-D1, c-Myc, MMP7, and MMP9. Taken together, our findings define a function for RBMS3 as an important tumor suppressor gene in NPC.published_or_final_versio

Polarity Switchable Photovoltages in Miscut La 0.67

We report the transient laser-induced anomalous photovoltaic effect in the La0.67Ca0.33MnO3 film grown on miscut LaSrAlO4 (001) substrate under 248 nm pulsed laser irradiation at ambient temperature without any applied bias. A photovoltaic pulse signal was observed when the La0.67Ca0.33MnO3 film was irradiated directly, and the signal polarity was reversed when the sample was irradiated through the LaSrAlO4 substrate, while the signal recorded between the two electrodes on the surface of LaSrAlO4 was not reversed when the sample was irradiated through La0.67Ca0.33MnO3 film rather than at the surface of LaSrAlO4. The switchable signal polarity provides a potential application of miscut manganite films as optical components. A possible mechanism is introduced to explain the experiment results