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

COMPARISON OF TORSO TWIST BETWEEN SLAP HIT AND ORDINARY HIT IN SOFTBALL BATTING

Softball batters take advantage of slap hit, by positioning the batters much closer to the first base. The purpose of this study was to compare the difference of torso twist between a slap hit and an ordinary hit in softball batting. Ten female college softball batters performed slap hits and ordinary hits. Reflective markers were placed on specific landmarks for each subject and VICON motion analysis system was used to record the hits. Slap hits showed less backward rotation during the torso wind-up phase while ordinary hit showed more forward rotation during the torso follow-through phase. No difference on trunk rotation was found at impact. The findings of this study suggested that the restricted backward torso twist during the wind-up phase and the limited forward torso twist during the follow-through phase should be taken into consideration in slap hits

Carbon Dioxide Angiography in Lower Limbs: A Prospective Comparative Study With Selective Iodinated Contrast Angiography

This was a prospective comparison of the accuracy and image quality of carbon dioxide digital subtraction angiography (CO2 DSA) and iodinated contrast digital subtraction angiography (ICDSA) in evaluating lower extremity arteries and patient tolerance of the procedures. Selective DSA was performed in 14 Taiwanese patients who were diagnosed with peripheral artery occlusive disease (PAOD). Both contrast materials were administered through mechanical injectors. Post-processing of the image used pixel shifting. Images of vessels were divided into 22 anatomic segments and evaluated by two experienced radiologists. A four-point scale was used to classify diseased vessels. Two interpreters rated the CO2 DSA image against the ICDSA image on a three-point scale. Patient tolerance was assessed from verbal descriptions. Cohen's kappa was used to determine interobserver agreement and descriptive statistics were used to summarize patient experience. Interobserver agreement ranged from fair to excellent, with most being good or excellent. Three patients (21.4%) could not tolerate the whole procedure and nine patients (64.3%) reported discomfort during the CO2 DSA procedure. CO2 DSA image quality was better for the thigh than the distal runoff and pelvic regions. Our results showed that selective CO2 DSA cannot replace ICDSA as a routine diagnostic tool for PAOD because it does not give images of comparative quality

Total white blood cell count or neutrophil count predict ischemic stroke events among adult Taiwanese: report from a community-based cohort study

BACKGROUND: Evidence about whether white blood cell (WBC) or its subtypes can act as a biomarker to predict the ischemic stroke events in the general population is scanty, particularly in Asian populations. The aim of this study is to establish the predictive ability of total WBC count or subtypes for long-term ischemic stroke events in the cohort population in Taiwan. METHODS: The Chin-Shan Community Cohort Study began from 1990 to 2007 by recruiting 1782 men and 1814 women of Chinese ethnicity. Following a total of 3416 participants free from ischemic stroke events at baseline for a median of 15.9 years; we documented 187 new incident cases. RESULTS: The multivariate relative risk for the comparison of the participants in the fifth and first WBC count quintiles was 1.67 (95% confidence interval [CI], 1.02–2.73; P for trend=0.03), and the corresponding relative risk for neutrophil count was 1.93 (95% CI, 1.13–3.29; P for trend=0.02). The discriminative ability by WBC and neutrophil counts were similar (area under the receiver operating characteristic curve, 0.600 for adding WBC, 0.610 for adding neutrophils, 0.595 for traditional risk factor model). In addition, the net reclassification improvement (NRI) values between the neutrophil and white blood cell count models were not significant (NRI, =-2.60%, P=0.35), indicating the similar discrimination performance for both WBC and neutrophil counts. CONCLUSIONS: WBC and neutrophil count had a similar ability to predict the long-term ischemic stroke events among Taiwanese

Ultraviolet C Irradiation Induces Different Expression of Cyclooxygenase 2 in NIH 3T3 Cells and A431 Cells: The Roles of COX-2 Are Different in Various Cell Lines

Ultraviolet C (UVC) is a DNA damage inducer, and 20 J/m2 of UVC irradiation caused cell growth inhibition and induced cell death after exposure for 24–36 h. The growth of NIH 3T3 cells was significantly suppressed at 24 h after UVC irradiation whereas the proliferation of A431 cells was inhibited until 36 h after UVC irradiation. UVC irradiation increased COX-2 expression and such up-regulation reached a maximum during 3–6 h in NIH 3T3 cells. In contrast, UVC-induced COX-2 reached a maximum after 24–36 h in A431 cells. Measuring prostaglandin E2 (PGE2) level showed a biphasic profile that PGE2 release was rapidly elevated in 1–12 h after UVC irradiation and increased again at 24 h in both cell lines. Treatment with the selective COX-2 inhibitor, SC-791, during maximum expression of COX-2 induction, attenuated the UVC induced-growth inhibition in NIH 3T3 cells. In contrast, SC-791 treatment after UVC irradiation enhanced death of A431 cells. These data showed that the patterns of UVC-induced PGE2 secretion from NIH 3T3 cells and A431 cells were similar despite the differential profile in UVC-induced COX-2 up-regulation. Besides, COX-2 might play different roles in cellular response to UVC irradiation in various cell lines

Persistent Tissue Kinetics and Redistribution of Nanoparticles, Quantum Dot 705, in Mice: ICP-MS Quantitative Assessment

Background: Quantum dots (QDs) are autofluorescent semiconductor nanocrystals that can be used for in vivo biomedical imaging. However, we know little about their in vivo disposition and health consequences. Objectives: We assessed the tissue disposition and pharmacokinetics of QD705 in mice. Methods: We determined quantitatively the blood and tissue kinetics of QD705 in mice after single intravenous (iv) injection at the dose of 40 pmol for up to 28 days. Inductively coupled plasma–mass spectrometry (ICP-MS) measurement of cadmium was the primary method of quantification of QD705. Fluorescence light microscopy revealed the localization of QD705 in tissues. Results: Plasma half-life of QD705 in mice was short (18.5 hr), but ICP-MS analyses revealed QD705 persisted and even continued to increase in the spleen, liver, and kidney 28 days after an iv dose. Considerable time-dependent redistribution from body mass to liver and kidney was apparent between 1 and 28 days postdosing. The recoveries at both time points were near 100%; all QD705s reside in the body. Neither fecal nor urinary excretion of QD705 was detected appreciably in 28 days postdosing. Fluorescence microscopy demonstrated deposition of QD705 in the liver, spleen, and kidneys. Conclusion: Judging from the continued increase in the liver (29–42% of the administered dose), kidney (1.5–9.2%), and spleen (4.8–5.2%) between 1 and 28 days without any appreciable excretion, QD705 has a very long half-life, potentially weeks or even months, in the body and its health consequences deserve serious consideration

Spinocerebellar ataxia type 8 larger triplet expansion alters histone modification and induces RNA foci

<p>Abstract</p> <p>Background</p> <p>Spinocerebellar ataxia type 8 (SCA8) involves the expression of an expanded CTG/CAG combined repeats (CR) from opposite strands producing CUG expansion transcripts (ataxin 8 opposite strand, ATXN8OS) and a polyglutamine expansion protein (ataxin 8, ATXN8). The pathogenesis of SCA8 is complex and the spectrum of clinical presentations is broad.</p> <p>Results</p> <p>Using stably induced cell models expressing 0, 23, 88 and 157 CR, we study the role of ATXN8OS transcripts in SCA8 pathogenesis. In the absence of doxycycline, the stable ATXN8OS CR cell lines exhibit low levels of ATXN8OS expression and a repeat length-related increase in staurosporine sensitivity and in the number of annexin positive cells. A repeat length-dependent repression of ATXN8OS expression was also notable. Addition of doxycycline leads to 25~50 times more ATXN8OS RNA expression with a repeat length-dependent increase in fold of ATXN8OS RNA induction. ChIP-PCR assay using anti-dimethyl-histone H3-K9 and anti-acetyl-histone H3-K14 antibodies revealed increased H3-K9 dimethylation and reduced H3-K14 acetylation around the ATXN8OS cDNA gene in 157 CR line. The repeat length-dependent increase in induction fold is probably due to the increased RNA stability as demonstrated by monitoring ATXN8OS RNA decay in cells treated with the transcriptional inhibitor, actinomycin D. In cells stably expressing ATXN8OS, RNA FISH experiments further revealed ribonuclear foci formation in cells carrying expanded 88 and 157 CR.</p> <p>Conclusion</p> <p>The present study demonstrates that the expanded CUG-repeat tracts are toxic to human cells and may affect ATXN8OS RNA expression and stability through epigenetic and post-transcriptional mechanisms.</p