Characterizing First Arrival Position Channels: Noise Distribution and Capacity Analysis

This paper addresses two fundamental problems in diffusive molecular communication: characterizing the first arrival position (FAP) density and bounding the information transmission capacity of FAP channels. Previous studies on FAP channel models, mostly captured by the density function of noise, have been limited to specific spatial dimensions, drift directions, and receiver geometries. In response, we propose a unified solution for identifying the FAP density in molecular communication systems with fully-absorbing receivers. Leveraging stochastic analysis tools, we derive a concise expression with universal applicability, covering any spatial dimension, drift direction, and receiver shape. We demonstrate that several existing FAP density formulas are special cases of this innovative expression. Concurrently, we establish explicit upper and lower bounds on the capacity of three-dimensional, vertically-drifted FAP channels, drawing inspiration from vector Gaussian interference channels. In the course of deriving these bounds, we unravel an explicit analytical expression for the characteristic function of vertically-drifted FAP noise distributions, providing a more compact characterization compared to the density function. Notably, this expression sheds light on a previously undiscovered weak stability property intrinsic to vertically-drifted FAP noise distributions.Comment: 30 pages; 3 figures, 1 table; this paper is submitted to IEEE Transactions on Communication

The ACR11 encodes a novel type of chloroplastic ACT domain repeat protein that is coordinately expressed with GLN2 in Arabidopsis

<p>Abstract</p> <p>Background</p> <p>The ACT domain, named after bacterial aspartate kinase, chorismate mutase and TyrA (prephenate dehydrogenase), is a regulatory domain that serves as an amino acid-binding site in feedback-regulated amino acid metabolic enzymes. We have previously identified a novel type of ACT domain-containing protein family, the ACT domain repeat (ACR) protein family, in <it>Arabidopsis</it>. Members of the ACR family, ACR1 to ACR8, contain four copies of the ACT domain that extend throughout the entire polypeptide. Here, we describe the identification of four novel ACT domain-containing proteins, namely ACR9 to ACR12, in <it>Arabidopsis</it>. The ACR9 and ACR10 proteins contain three copies of the ACT domain, whereas the ACR11 and ACR12 proteins have a putative transit peptide followed by two copies of the ACT domain. The functions of these plant ACR proteins are largely unknown.</p> <p>Results</p> <p>The ACR11 and ACR12 proteins are predicted to target to chloroplasts. We used protoplast transient expression assay to demonstrate that the <it>Arabidopsis </it>ACR11- and ACR12-green fluorescent fusion proteins are localized to the chloroplast. Analysis of an <it>ACR11 </it>promoter-β-glucuronidase (GUS) fusion in transgenic <it>Arabidopsis </it>revealed that the GUS activity was mainly detected in mature leaves and sepals. Interestingly, coexpression analysis revealed that the <it>GLN2</it>, which encodes a chloroplastic glutamine synthetase, has the highest mutual rank in the coexpressed gene network connected to <it>ACR11</it>. We used RNA gel blot analysis to confirm that the expression pattern of <it>ACR11 </it>is similar to that of <it>GLN2 </it>in various organs from 6-week-old <it>Arabidopsis</it>. Moreover, the expression of <it>ACR11 </it>and <it>GLN2 </it>is highly co-regulated by sucrose and light/dark treatments in 2-week-old <it>Arabidopsis </it>seedlings.</p> <p>Conclusions</p> <p>This study reports the identification of four novel ACT domain repeat proteins, ACR9 to ACR12, in <it>Arabidopsis</it>. The ACR11 and ACR12 proteins are localized to the chloroplast, and the expression of <it>ACR11 </it>and <it>GLN2 </it>is highly coordinated. These results suggest that the <it>ACR11 </it>and <it>GLN2 </it>genes may belong to the same functional module. The <it>Arabidopsis </it>ACR11 protein may function as a regulatory protein that is related to glutamine metabolism or signaling in the chloroplast.</p

A rare complication in a child undergoing chemotherapy for acute lymphoblastic leukemia: Superior sagittal sinus thrombosis

AbstractWe report the case of a 4-year-old boy with acute lymphoblastic leukemia in high-risk group who suffered from generalized tonic-colonic seizure evolving into status epilepticus, and subsequent left hemiparesis during his first reinduction chemotherapy, consisting of dexamethasone, vincristine, l-asparaginase, and epirubicin. Superior sagittal sinus and cerebral venous thrombosis, predominantly in right side, were proved by brain magnetic resonance imaging. After aggressive treatment with low-molecular weight heparin (LMWH), left hemiparesis improved in 1 week. And he was fully ambulatory 3 weeks later. The second cycle of reinduction chemotherapy was conducted smoothly with the concomitant use of LMWH. This case illustrates the strong correlation of the rare thrombotic complication, superior sagittal sinus thrombosis, and hypercoagulable status secondary to combination use of l-asparaginase and corticosteroid. Early and vigilant recognition of superior sagittal sinus thrombosis and prompt anticoagulation with LMWH may prevent further neurological damage

The iNOS/Src/FAK axis is critical in Toll-like receptor-mediated cell motility in macrophages

AbstractThe Toll-like receptors (TLRs) play a pivotal role in innate immunity for the detection of highly conserved, pathogen-expressed molecules. Previously, we demonstrated that lipopolysaccharide (LPS, TLR4 ligand)-increased macrophage motility required the participation of Src and FAK, which was inducible nitric oxide synthase (iNOS)-dependent. To investigate whether this iNOS/Src/FAK pathway is a general mechanism for macrophages to mobilize in response to engagement of TLRs other than TLR4, peptidoglycan (PGN, TLR2 ligand), polyinosinic–polycytidylic acid (polyI:C, TLR3 ligand) and CpG-oligodeoxynucleotides (CpG, TLR9 ligand) were used to treat macrophages in this study. Like LPS stimulation, simultaneous increase of cell motility and Src (but not Fgr, Hck, and Lyn) was detected in RAW264.7, peritoneal macrophages, and bone marrow-derived macrophages exposed to PGN, polyI:C and CpG. Attenuation of Src suppressed PGN-, polyI:C-, and CpG-elicited movement and the level of FAK Pi-Tyr861, which could be reversed by the reintroduction of siRNA-resistant Src. Besides, knockdown of FAK reduced the mobility of macrophages stimulated with anyone of these TLR ligands. Remarkably, PGN-, polyI:C-, and CpG-induced Src expression, FAK Pi-Tyr861, and cell mobility were inhibited in macrophages devoid of iNOS, indicating the importance of iNOS. These findings corroborate that iNOS/Src/FAK axis occupies a central role in macrophage locomotion in response to engagement of TLRs

High expression FUT1 and B3GALT5 is an independent predictor of postoperative recurrence and survival in hepatocellular carcinoma.

Cancer may arise from dedifferentiation of mature cells or maturation-arrested stem cells. Previously we reported that definitive endoderm from which liver was derived, expressed Globo H, SSEA-3 and SSEA-4. In this study, we examined the expression of their biosynthetic enzymes, FUT1, FUT2, B3GALT5 and ST3GAL2, in 135 hepatocellular carcinoma (HCC) tissues by qRT-PCR. High expression of either FUT1 or B3GALT5 was significantly associated with advanced stages and poor outcome. Kaplan Meier survival analysis showed significantly shorter relapse-free survival (RFS) for those with high expression of either FUT1 or B3GALT5 (P = 0.024 and 0.001, respectively) and shorter overall survival (OS) for those with high expression of B3GALT5 (P = 0.017). Combination of FUT1 and B3GALT5 revealed that high expression of both genes had poorer RFS and OS than the others (P &lt; 0.001). Moreover, multivariable Cox regression analysis identified the combination of B3GALT5 and FUT1 as an independent predictor for RFS (HR: 2.370, 95% CI: 1.505-3.731, P &lt; 0.001) and OS (HR: 2.153, 95% CI: 1.188-3.902, P = 0.012) in HCC. In addition, the presence of Globo H, SSEA-3 and SSEA-4 in some HCC tissues and their absence in normal liver was established by immunohistochemistry staining and mass spectrometric analysis

Outcome for self-expandable metal stents in patients with malignant gastroduodenal obstruction: A single center experience

SummaryBackgroundMalignant gastric outlet obstruction causes significant malnutrition and morbidity. The implantation of a metallic stent is an alternative palliative treatment to allow the intake of food in these patients.Patients and MethodsThirty-eight consecutive patients with malignant gastric outlet obstruction who had received an uncovered metallic stent placement in our department from April 2010 to April 2012 were enrolled for analysis. The mean follow-up time was 6.3 months. Food intake, measured by the Gastric Outlet Obstruction Scoring System, complications, duration of stent patency, and survival were evaluated.ResultsThe technical and clinical success rates of the procedure were 100% and 94.7%, respectively. The Gastric Outlet Obstruction Scoring System scores were significantly improved at 1 day, 7 days, and 30 days after the implantation compared with those prior to the procedure (p < 0.001). Aspiration pneumonia developed in two patients (5.2%) after the procedure. One of these patients developed respiratory failure and died 3 days later. Stent dysfunction developed in 11 of 38 patients (28.9%) during the follow-up period; one patient (2.6%) experienced migration of the stent 38 days later due to resolution of the stricture; 10 patients (26.3%) had stent restenosis. The median time of stent patency was 120 days. The presence of peritoneal carcinomatosis when the procedure was carried out was a significantly poor predictive factor of stent patency [hazard ratio (HR) 7.9, p = 0.039]. The median survival of the patients was 156 days. Poor performance status ≥3; HR 2.647, p = 0.012) and nongastric cancer origin (HR 3.466, p = 0.008) were associated with a significantly short survival time.ConclusionMetallic stent placement is an effective and relatively safe treatment for patients with malignant gastric outlet obstruction

γ\gamma-SUP: A clustering algorithm for cryo-electron microscopy images of asymmetric particles

Cryo-electron microscopy (cryo-EM) has recently emerged as a powerful tool for obtaining three-dimensional (3D) structures of biological macromolecules in native states. A minimum cryo-EM image data set for deriving a meaningful reconstruction is comprised of thousands of randomly orientated projections of identical particles photographed with a small number of electrons. The computation of 3D structure from 2D projections requires clustering, which aims to enhance the signal to noise ratio in each view by grouping similarly oriented images. Nevertheless, the prevailing clustering techniques are often compromised by three characteristics of cryo-EM data: high noise content, high dimensionality and large number of clusters. Moreover, since clustering requires registering images of similar orientation into the same pixel coordinates by 2D alignment, it is desired that the clustering algorithm can label misaligned images as outliers. Herein, we introduce a clustering algorithm $\gamma$-SUP to model the data with a $q$-Gaussian mixture and adopt the minimum $\gamma$-divergence for estimation, and then use a self-updating procedure to obtain the numerical solution. We apply $\gamma$-SUP to the cryo-EM images of two benchmark macromolecules, RNA polymerase II and ribosome. In the former case, simulated images were chosen to decouple clustering from alignment to demonstrate $\gamma$-SUP is more robust to misalignment outliers than the existing clustering methods used in the cryo-EM community. In the latter case, the clustering of real cryo-EM data by our $\gamma$-SUP method eliminates noise in many views to reveal true structure features of ribosome at the projection level.Comment: Published in at http://dx.doi.org/10.1214/13-AOAS680 the Annals of Applied Statistics (http://www.imstat.org/aoas/) by the Institute of Mathematical Statistics (http://www.imstat.org

The Tiehchanshan structure of NW Taiwan: A potential geological reservoir for CO2 sequestration

The Tiehchanshan structure is the largest gas-field in the outer foothills of northwestern Taiwan and has been regarded as the best site for CO2 sequestration. This study used a grid of seismic sections and wellbore data to establish a new 3-D geometry of subsurface structure, which was combined with lithofacies characters of the target reservoir rock, the Yutengping Sandstone, to build a geological model for CO2 sequestration. On the surface, the Tiehchanshan structure is characterized by two segmented anticlines offset by a tear fault. The subsurface geometry of the Tiehchanshan structure is, however, composed of two thrust-related anticlines with opposite vergence and laterally increasing fold symmetry toward each other. The folds are softly linked via the transfer zone in the subsurface, implying that the suspected tear fault in the surface transfer zone may not exist in the subsurface. The Yutengping Sandstone is composed of several sandstone units characterized by coarsening-upward cycles. The sandstone member can be further divided into four well-defined sandstone layers, separated by laterally continuous shale layers. In view of the structural and stratigraphic characteristics, the optimum area for CO2 injection and storage is in the structurally high in the northern part of the Tiehchanshan structure. The integrity of the closure and the overlying seal are not disrupted by the pre-orogenic high-angle faults. On the other hand, a thick continuous shale layer within the Yutengping Sandstone isolates the topmost sandy layer from the underlying ones and gives another important factor to the CO2 injection simulation