Arm Segments Research Articles

New articulated asteroids (Echinodermata, Asteroidea) and ophiuroids (Echinodermata, Ophiuroidea) from the Late Jurassic (Volgian / Tithonian) of central Spitsbergen

The Late Jurassic–Early Cretaceous Slottsmøya Member of the Agardhfjellet Formation in central Spitsbergen has yielded two new species of asteroids and two species of ophiuroids, one of which is described as new. Polarasterias janusensis Rousseau & Gale gen. et sp. nov. is a forcipulatid neoasteroid with elongated arms, small disc and very broad ambulacral grooves with narrow adambulacrals. Savignaster septemtrionalis Rousseau & Gale sp. nov. is a pterasterid with well-developed interradial chevrons. The Spitsbergen specimens are the first described articulated material of Savignaster and reveal the overall arrangement of the ambulacral groove ossicles. Ophiogaleus sp. is an ophiacanthid with relatively long jaws and lateral arm plates, with a coarsely reticulate outer surface. Here again, we report the first articulated skeletons of this genus, providing unprecedented insights into the disc morphology. Ophioculina hoybergia Rousseau & Thuy gen. et sp. nov. is an ophiopyrgid with a well-developed arm comb and tentacle pores reduced to within-plate perforations starting at median arm segments. These new finds are important additions to the asterozoan fossil record with regard to their good degree of articulation and the high latitudinal position of the localities. They significantly add to the set of exhaustively known fossil asterozoan taxa which play a key role in the phylogenetic analysis and reconstruction of evolutionary history.

Syndrome del(5)(q14~23),der(10)(p12p15)?add(10)(q26): Case report and literature review

Structural chromosomal mutations are changes that do not modify the number of chromosomes in the cell, but they determine the appearance of abnormal chromosomes. The aim of this study is to report the clinical and cytogenetic history of a patient carrier of a structural mutation with karyotype 46,XY,del(5)(q14~23),der(10)(p12p15)?add(10)(q26) attended by the Genetic Counseling Service of the State University of Londrina. The patient (ABT) is male, had 1 year and 9 months on the day of the examination, normally born, full term (38 weeks) with Psychomotor Development Retardation (PDR) and without other complications. At birth, ABT’s mother was 25 years old and his father was 31 years old. The x-ray, urine analysis, pre- and postnatal ultrasonography, parasitological, ophthalmologic, gastrointestinal and neurological exams do not reveal changes. At the time of cytogenetic examination, the patient underwent surgery for the treatment of esophagogastric reflux and inguinal hernia. Currently, ABT follows up with Pediatrician, Social Worker, Physiotherapist, Speech Therapist, Neuropediatrician, Nutritionist and Ophthalmologist. These findings, particularly PDR, were consistent with the rare syndrome of the 10q + chromosome, since only ten cases of trisomy for the distal segment of the major arm of chromosome 10 (10q +) were described. Excluding the PDR, other characteristics were not found in the trial. Structural chromosomal syndromes represent an opportunity to understand clinical phenotypes and become important in gene mapping, especially when associated with molecular genetic techniques, the next step in diagnostic genetic research. In this way, the patient follows the treatment of the symptomatology.

Geometric Aspects and Testing of the Galactic Center Distance Determination from Spiral Arm Segments

We consider the problem of determining the geometric parameters of a Galactic spiral arm from its segment by including the distance to the spiral pole, i.e., the distance to the Galactic center ($R_0$). The question about the number of points belonging to one turn of a logarithmic spiral and defining this spiral as a geometric figure has been investigated numerically and analytically by assuming the direction to the spiral pole (to the Galactic center) to be known. Based on the results obtained, in an effort to test the new approach, we have constructed a simplified method of solving the problem that consists in finding the median of the values for each parameter from all possible triplets of objects in the spiral arm segment satisfying the condition for the angular distance between objects. Applying the method to the data on the spatial distribution of masers in the Perseus and Scutum arms (the catalogue by Reid et al. (2014)) has led to an estimate of $R_0 = 8.8 \pm 0.5$ kpc. The parameters of five spiral arm segments have been determined from masers of the same catalogue. We have confirmed the difference between the spiral arms in pitch angle. The pitch angles of the arms revealed by masers are shown to generally correlate with $R_0$ in the sense that an increase in $R_0$ leads to a growth in the absolute values of the pitch angles.

A new species ofOphioconis(Echinodermata: Ophiuroidea) from Ryukyu Islands, southwestern Japan

Ophioconis claviculata sp. nov. is described on the basis of three specimens collected from Ryukyu Islands, southwestern, Japan. The new species is distinct in having: disc covered by granules; four, sometimes five flat, polygonal oral papillae on each side of jaw; broad and flat teeth with hyaline distal end; spiniform and conical arm spines, two times longer than the corresponding arm segment at the maximum length; oralmost arm spines on proximal portion of arms flattened and clavate; four tentacle scales on third tentacle pore; and ventral arm plate longer than wide, with concentrate lamellar striations. The new species was found under rocks of open water as well as in a dark and medium to low salinity (28 ppt) environment of submarine cave, suggesting that this species tolerate this specific condition.

Report of One Case with Congenital Vascular Ring

Congenital vascular rings is an unusual congenital condition and severely affects the survival and life quality of the patients. A 23-year-old gravid woman was referred for counseling at 24 weeks of gestation because of abnormal ultrasound findings of fetal congenital vascular ring. Fetal echocardiography showed a complete vascular ring with a right aortic arch (RAA), left ductus arteriosus (LDA) and left intracardia echogenicfocus. Conventional cytogenetic analysis revealed an apparent balanced reciprocal translocation between the distal segment of the long arm of a chromosome 5 and the long arm of chromosome 2: 46, XY, t (2;5) (q3.5; q31.1). This abnormal karyotype was detected in gravid woman. However, the microarray analysis on amniocytes using HumanCytoSNP-12 array detected 2.57-Mb deletion at 22q11.21. Metaphase fluorescence in situ hybridization (FISH) analysis on cultured amniocytes confirmed an interstitial 22q11.2 deletion. The fetus was died owing to breathing and feeding difficulties. Our study highlights the clinical value of genetic detection and prenatal diagnosis of Congenital vascular rings by karyotype analysis coupled with SNP array.

Retinoblastoma familial associado a carcinoma primário de plexo coróide

Retinoblastoma é um tumor originado de células neuropiteliais da retina, que pode ocorrer de forma esporádica ou familial e está relacionado com o gene RB-l, do braço longo do cromossomo 13 {região 13q/14). Este gene é um supressor tumoral e quando sofre delação promove crescimento celular. O retinoblastoma relaciona-se com a mutação dos dois alelos RB-1: quando o indivíduo sofre duas mutações durante o desenvolvimento somático da retina, ele tem a forma esporádica ou não hereditária da doença; quando uma das mutações é herdada das células germinativas, ele tem a familial ou hereditária. Apresentamos um caso de retinoblastoma bilateral, familial, associado com carcinoma primário do plexo coróide. Após revisão, não encontramos associação semelhante na literatura.

Selective distortion of body image by asynchronous visuotactile stimulation

In the rubber hand illusion (RHI), a rubber hand is felt as being part of one’s body. This illusion is evoked by providing synchronous visuotactile stimulation to the fake and real hands. Asynchronous visuotactile stimulation is known not to produce such an illusion of ownership, being commonly used as the control condition. Here we explored the impact of synchronous and asynchronous visuotactile stimulation on the body image. We combined the induction of the RHI with a quantitative test for the internal representation of body metrics (i.e., the positions of key fiducial points on the body relative to each other). We found a significant recalibration of the upper/lower arm lengths following asynchronous visuotactile stimulation. In particular, we observed a selective elongation of the lower arm, a distortion typical of deafferentation. Conversely, synchronous visuotactile stimulation did not alter the estimation of the arm segments' length. Our findings are consistent with a dynamic internal representation of body image that is continuously updated based on incoming multisensory information. Furthermore, the use of asynchronous multisensory stimulation as a neutral condition should be reconsidered since it introduces changes in the body image.

Abstract PR02: Mechanisms of NT5C2 activating mutations driving thiopurine resistance in relapsed lymphoblastic leukemia

Abstract Activating mutations in cytosolic 5'-nucleotidase II (NT5C2) drive resistance to 6-mercaptopurine (6-MP) in relapsed acute lymphoblastic leukemia (ALL). These gain-of function alleles encode proteins with increased nucleotidase activity, yet their specific molecular mechanisms are poorly understood. Allosteric activation of NT5C2 is primarily mediated by a marked conformational change in the helix A region, which reconfigures the catalytic center for substrate access and catalysis. Here we demonstrate that constitutively active NT5C2 mutant proteins (K359Q and L375F) adopt active helix A region structures in the absence of allosteric activator. Moreover, crystallographic, structural modeling, genetic, and functional antibody analyses identify a switch-off mechanism mediated by the dynamic mobilization of Asp407 in the tip region of the arm segment which, guided by positively charged residues located in the surface of a basic inter-monomeric cavity exposed upon allosteric activation, turns off NT5C2 by interacting with and disrupting the helical conformation of helix A. Loss of this regulatory mechanism in NT5C2 mutants involving the tip region of the arm segment and the inter-monomeric cavity drives increased nucleotidase activity and allosteric response. Finally, increased allosteric activation by the Q523X mutation results from loss of the NT5C2 C-terminal acidic tail segment, which promotes a closed inactive state in basal conditions. These results uncover dynamic mechanisms responsible for NT5C2 regulation targeted by chemotherapy resistance-driving NT5C2 mutations, with important implications for the development of NT5C2 inhibitor therapies. This abstract is also being presented as Poster 05. Citation Format: Chelsea L. Dieck, Gannie Tzoneva, Farhad Forouhar, Zachary Carpenter, Marta Sanchez-Martin, Alberto Ambesi-Impiombato, Renate Kirschner-Schwabe, Scott Lew, Jayaraman Seetharaman, Liang Tong, Adolfo Ferrando. Mechanisms of NT5C2 activating mutations driving thiopurine resistance in relapsed lymphoblastic leukemia [abstract]. In: Proceedings of the Second AACR Conference on Hematologic Malignancies: Translating Discoveries to Novel Therapies; May 6-9, 2017; Boston, MA. Philadelphia (PA): AACR; Clin Cancer Res 2017;23(24_Suppl):Abstract nr PR02.

INSIGHTS INTO THE TAXONOMY AND PALEOECOLOGY OF THE ‘BEAD BED' CRINOID (ECHINODERMATA: CRINOIDEA) BASED ON NEW MATERIAL FROM THE LOWER SILURIAN BRASSFIELD FORMATION OF EAST-CENTRAL KENTUCKY

The lower Silurian Brassfield Formation crops out throughout eastern midcontinent North America as a prominent carbonate deposit representing a variety of shoal to shallow shelf environments. The upper portion of this unit throughout Ohio and Kentucky is characterized by the exceptional abundance of distinctive crinoid columnals historically referred to as ‘beads'. Although recognized for more than a century, the taxonomic identity of the crinoid responsible for producing these elements remains unknown; this is due largely to the taphonomic state of ‘beads', which are nearly always preserved as isolated ossicles not commonly discovered as articulated segments and never in direct association with identifiable calyx plates or arm segments. Recently discovered material from east-central Kentucky allows these columnals to be confidently attributed to the morphogenus Floricolumnus (col.) Donovan and Clark. These elements are now recognized as components of a coiled dististelar attachment structure. There is also an association between ‘beads' and crown material, namely small, uniserial, pinnulate brachials. Collectively, this material supports the interpretation that the producer of these columnals was a large diplobathrid camerate, almost certainly a dimerocrinitid.

Novel Structural Abnormalities Involving Chromosomes 1, 17 and 2 Identified by Fluorescence In Situ Hybridization (FISH) and/or Cytogenetic Karyotyping in Kelly and SH-SY5Y Human Neuroblastoma Cell Lines, Respectively

Abstract: MYCN amplification and 1p36 deletion are important poor prognostic factors in neuroblastoma. 1p36 deletion and unbalanced translocations involving chromosomes 1, 17 and 2p were often reported in neuroblastoma cell lines. We aimed to investigate novel chromosomal abnormalities that are likely to affect neuroblastoma progression in Kelly and SH-SY5Y cell lines. Therefore, we analyzed the metaphase chromosomes using fluorescence in situ hybridization (FISH) method with probes specific to the chromosome bands 2p24 and 1p36 in SH-SY5Y and Kelly, respectively. Moreover, the rearrangements of chromosomes 1 and 17 from Kelly were re-examined by cytogenetic karyotyping. FISH analysis shows duplication of chromosome 2p24 on the long arm of a partner chromosome resulted from an unbalanced translocation der(?9)t(2;?9)(p24;q?34) in SH-SY5Y, suggesting that duplication of 2p24 locus containing MYCN gene may contribute to triggering MYCN amplification in neuroblastoma. On the other hand, FISH and karyotype analyses reveal three copies of chromosome 1 that consist of an intact chromosome 1, an extra derivative chromosome 1 with terminal and interstitial deletions (:p32→q25::q41→qter), and another including only interstitial deletion (pter→q25::q41→qter), leading to monosomy of the long arm segment 1q25-q41 in Kelly. These results suggest that chromosome 1q25-q41 may contain one or more tumour suppressor genes important for neuroblastoma progression. Together, FISH analysis shows that an additional 1p36 locus in Kelly is translocated to the short arm of extra chromosome 17, where the p53 tumour suppressor gene is located. Consequently, these novel structural abnormalities involving chromosomes 1, 17 and 2 could be contributed to the tumourigenicity of neuroblastoma cells.

Mechanisms of NT5C2 mutations Driving Thiopurine Resistance in Acute Lymphoblastic Leukemia

▪Relapse acute lymphoblastic leukemia (ALL) is associated with chemotherapy resistance and poor prognosis. Persistent leukemia initiating cells with increased self-renewal capacity, clonal heterogeneity and selection of resistance-driving genetic alterations have been proposed as drivers of leukemia relapse. Gain of function mutations in the 5'-Nucleotidase, Cytosolic II (NT5C2) gene are selectively present in relapsed ALL and confer resistance to chemotherapy with 6-mercaptopurine (6-MP). Yet, the specific mechanisms mediating constitutive activation of NT5C2 remain unknown. Here we performed detailed genetic, enzymatic, structural and functional analyses of relapsed leukemia-associated NT5C2 mutant alleles uncovering previously unrecognized functional heterogeneity in their mechanisms of action. Specifically, detailed nucleotidase assays in the presence of increased concentration of allosteric activators across 10 relapse-associated NT5C2 mutant proteins and analyses of the crystal structures of 7 distinct mutant proteins and wild type NT5C2 in the presence and absence of allosteric factors defined three classes of NT5C2 mutants with distinct mechanisms of action. Class I NT5C2 mutations force an active configuration of the NT5C2 catalytic center in the absence of allosteric activator. In contrast, class II NT5C2 mutations disrupt a novel switch-off mechanism mediated by the dynamic mobilization of the tip region of the arm segment responsible for returning the enzyme to its basal inactive configuration following allosteric activation. Finally, increased allosteric response in the class III p.Gln523* truncating mutation results from loss of the C-terminal acidic tail of NT5C2, which functions as a lock stabilizing the enzyme in its inactive basal configuration. The proposed role of the arm domain region and the C-terminal segment were verified in enzymatic assays incubating wild type NT5C2 with antibodies recognizing these regulatory elements, which phenocopied the increased enzymatic activity and response to allosteric effector of NT5C2 mutations involving these domains. In all, these results identify distinct molecular mechanisms mediating NT5C2 regulation targeted by activating NT5C2 mutant alleles and serve as a framework for the functional annotation of clinically-relevant NT5C2 mutations in relapsed ALL. Finally, the prominent role of the allosteric binding site as critical mediator of the mechanisms mediating thhe increased nucleotidase activity of NT5C2 mutant proteins point to this region as a preferred target for the design of NT5C2 inhibitors for the reversal of chemotherapy resistance in relapsed ALL.Figure 1 Relapse associated NT5C2 mutations and crystal structure of basal and activated wild type human NT5C2. (a) Graphical representation of relapse associated mutations in B-ALL (black) and T-ALL (red).(b-d) In vitro nucleotidase assays assessing the enzymatic activity of (b)class I, (c) class II, and (d)class IIINT5C2 mutations in the presence of increased concentrations of ATP. (e) A Ribbon diagram of the basal structure of wild type NT5C2-X537, displaying the HAD domain (cyan) and its three extensions: N-terminal segment (orange), arm (pink), and C-terminal segment (marine). The mutation sites are depicted as red solid spheres for Cα of each mutated amino acid. The phosphate (yellow for phosphorus) and Mg ions (dark green) are depicted as stick models and solid spheres respectively. (f) A Ribbon diagram of the activated structure of the full-length wild type NT5C2, in which the allosteric helix A (αA) is shown in dark purple. (g,h) Ribbon and surface (for subunit B) depictions of basal and activated dimers of (g) NT5C2-X537 and the (h) full-length, respectively. (i,j) Ribbon diagrams of the basal (i) NT5C2-X537 and activated (j) full-length wild type tetramers, respectively. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

22q11.2 microdeletion in two adolescent patients who presented with convulsion

22q11.2 microdeletion which involves DiGeorge syndrome, velo-cardiofacial syndrome and conotruncal anomaly face syndrome occurs as a result of a deletion in the short segment of the long arm of the 22th chromosome. Patients with this syndrome have a wide clinical spectrum including learning difficulty, dysmorphic face, cardiac anomalies, hypocalcemia, hypoparathyroidism, cleft palate, thymus anomalies, immune failure and speech and feeding problems. The number of clinical characteristics which have been reported to be related with this syndrome is higher than 180. All anomalies may not be present in all patients. In this article, a 12-year old female patient who was found to have 22q11.2 microdeletion with mild mental retardation and dysmorphic face and who presented to our hospital because of convulsion and a 13-year old male patient who was found to have 22q11.2 microdeletion with hypocalcemia, hypoparathyroidism, dysmorphic face and mental retardation and who presented to our hospital because of convulsion (it was learned from his history that he was being followed up in another center because of autism) were presented.

The Spiral Arm Segments of the Galaxy within 3 kpc from the Sun: A Statistical Approach

Abstract As can be reasonably expected, upcoming large-scale APOGEE, GAIA, GALAH, LAMOST, and WEAVE stellar spectroscopic surveys will yield rather noisy Galactic distributions of stars. In view of the possibility of employing these surveys, our aim is to present a statistical method to extract information about the spiral structure of the Galaxy from currently available data, and to demonstrate the effectiveness of this method. The model differs from previous works studying how objects are distributed in space in its calculation of the statistical significance of the hypothesis that some of the objects are actually concentrated in a spiral. A statistical analysis of the distribution of cold dust clumps within molecular clouds, H ii regions, Cepheid stars, and open clusters in the nearby Galactic disk within 3 kpc from the Sun is carried out. As an application of the method, we obtain distances between the Sun and the centers of the neighboring Sagittarius arm segment, the Orion arm segment in which the Sun is located, and the Perseus arm segment. Pitch angles of the logarithmic spiral segments and their widths are also estimated. The hypothesis that the collected objects accidentally form spirals is refuted with almost 100% statistical confidence. We show that these four independent distributions of young objects lead to essentially the same results. We also demonstrate that our newly deduced values of the mean distances and pitch angles for the segments are not too far from those found recently by Reid et al. using VLBI-based trigonometric parallaxes of massive star-forming regions.

Multi-body dynamic coupling mechanism for generating throwing arm velocity during baseball pitching

The purpose of this study was to identify the detailed mechanism how the maximum throwing arm endpoint velocity is determined by the muscular torques and non-muscular interactive torques from the perspective of the dynamic coupling among the trunk, thorax and throwing and non-throwing arm segments. The pitching movements of ten male collegiate baseball pitchers were measured by a three-dimensional motion capture system. Using the induced-segmental velocity analysis (IVA) developed in this study, the maximum fingertip velocity of the throwing arm (MFV) was decomposed into each contribution of the muscular torques, passive motion-dependent torques due to gyroscopic moment, Coriolis force and centrifugal force, and other interactive torque components. The results showed that MFV (31.6±1.7m/s) was mainly attributed to two different mechanisms. The first is the passive motion-dependent effect on increasing the angular velocities of three joints (thorax rotation, elbow extension and wrist flexion). The second is the muscular torque effect of the shoulder internal rotation (IR) torque on generating IR angular velocity. In particular, the centrifugal force-induced elbow extension motion, which was the greatest contributor among individual joint contributions, was caused primarily by the angular velocity-dependent forces associated with the humerus, thorax, and trunk rotations. Our study also found that a compensatory mechanism was achieved by the negative and positive contributions of the muscular torque components. The current IVA is helpful to understand how the rapid throwing arm movement is determined by the dynamic coupling mechanism.

Facile, Efficient Synthesis of Star‐Shaped π‐Conjugated Systems by Combined Olefin Metathesis with Wittig‐type Coupling

Precise, efficient one‐pot synthesis of star shaped (tri‐, tetra‐arm) π‐conjugated systems has been achieved by olefin metathesis of 5‐substituted‐2‐propenyl‐thiophene or N‐vinyl carbazole (arm segment) using a molybdenum‐alkylidene reagent and subsequent Wittig‐type cleavage with core segments containing aldehydes [tri(4‐formylphenyl)amine, 2,4,6‐tri(4‐formyl‐biphenyl)benzene, 1,4‐dimethoxy‐2,3,5,6‐tetra(4‐formylphenyl)‐benzene, etc.]; effects of the core and the arm have been clearly demonstrated.

Spiral arms and disc stability in the Andromeda galaxy

Aims: Density waves are often considered as the triggering mechanism of star formation in spiral galaxies. Our aim is to study relations between different star formation tracers (stellar UV and near-IR radiation and emission from HI, CO and cold dust) in the spiral arms of M31, to calculate stability conditions in the galaxy disc and to draw conclusions about possible star formation triggering mechanisms. Methods: We select fourteen spiral arm segments from the de-projected data maps and compare emission distributions along the cross sections of the segments in different datasets to each other, in order to detect spatial offsets between young stellar populations and the star forming medium. By using the disc stability condition as a function of perturbation wavelength and distance from the galaxy centre we calculate the effective disc stability parameters and the least stable wavelengths at different distances. For this we utilise a mass distribution model of M31 with four disc components (old and young stellar discs, cold and warm gaseous discs) embedded within the external potential of the bulge, the stellar halo and the dark matter halo. Each component is considered to have a realistic finite thickness. Results: No systematic offsets between the observed UV and CO/far-IR emission across the spiral segments are detected. The calculated effective stability parameter has a minimal value Q_{eff} ~ 1.8 at galactocentric distances 12 - 13 kpc. The least stable wavelengths are rather long, with the minimal values starting from ~ 3 kpc at distances R > 11 kpc. Conclusions: The classical density wave theory is not a realistic explanation for the spiral structure of M31. Instead, external causes should be considered, e.g. interactions with massive gas clouds or dwarf companions of M31.

The PdBI Arcsecond Whirlpool Survey (PAWS): The Role of Spiral Arms in Cloud and Star Formation

Abstract The process that leads to the formation of the bright star-forming sites observed along prominent spiral arms remains elusive. We present results of a multi-wavelength study of a spiral arm segment in the nearby grand-design spiral galaxy M51 that belongs to a spiral density wave and exhibits nine gas spurs. The combined observations of the (ionized, atomic, molecular, dusty) interstellar medium with star formation tracers (H ii regions, young <10 Myr stellar clusters) suggest (1) no variation in giant molecular cloud (GMC) properties between arm and gas spurs, (2) gas spurs and extinction feathers arising from the same structure with a close spatial relation between gas spurs and ongoing/recent star formation (despite higher gas surface densities in the spiral arm), (3) no trend in star formation age either along the arm or along a spur, (4) evidence for strong star formation feedback in gas spurs, (5) tentative evidence for star formation triggered by stellar feedback for one spur, and (6) GMC associations being not special entities but the result of blending of gas arm/spur cross sections in lower resolution observations. We conclude that there is no evidence for a coherent star formation onset mechanism that can be solely associated with the presence of the spiral density wave. This suggests that other (more localized) mechanisms are important to delay star formation such that it occurs in spurs. The evidence of star formation proceeding over several million years within individual spurs implies that the mechanism that leads to star formation acts or is sustained over a longer timescale.

Label-free fluorescent strategy for sensitive detection of tetracycline based on triple-helix molecular switch and G-quadruplex

In this assay, a label-free fluorescent sensing platform based on triple-helix molecular switch (THMS) and G-quadruplex was developed for the detection of tetracycline. We demonstrated this approach by using THMS, which consists of a central section with a shortened 8-mer aptamer sequence with high affinity to tetracycline and flanked by two arm segments. G-rich oligonucleotide can specifically bind to thioflavin T (ThT) as a signal transduction probe (STP). In the absence of tetracycline, THMS remains stable, the fluorescence of background is low. By the addition of target tetracycline, the aptamer-target binding results in the formation of a structured aptamer-target complex, which disassembles the THMS and releases the STP. The free STP self-assembles into G-quadruplex and specifically binds to ThT which generates a obvious fluorescence enhancement. Using the triple-helix molecular switch, the developed aptamer-based fluorescent sensing platform showed a linear relationship with the concentration of tetracycline ranging from 0.2 to 20.0nmol/L. The detection limit of tetracycline was determined to be 970.0pmol/L. The assay avoids complicated modifications or chemical labeling, making it simple and cost-effective. So, it is expected that this aptamer-based fluorescent assay could be extensively applied in the field of food safety inspection.

Effects of cognitive task execution on stable and unstable surface balance

AbstractCompromised balance with respect to both stable and passively unstable surfaces can potentially affect performance of many occupational, recreational and daily living tasks. Many tasks that require some level of balance maintenance, however, also involve burdens on individuals’ cognitive systems. Consequently the purpose of this project was to investigate the effects of performing cognitive tasks on stable surface and passively unstable surface balance performance. Participants in this study performed balance task on a passible unstable surface, as well as on a stable surface, with and without concurrent quantitative and language based cognitive tasks. Concurrent cognitive tasks did not demonstrate statistically significant effects on stable surface balance. For unstable surface balance, concurrent cognitive tasks had significant effects on trunk and arm segment angular velocities, while significant effects on movement of the passively unstable surface were not observed. The lack of cognitive task...

ASTErIsM: application of topometric clustering algorithms in automatic galaxy detection and classification

We present a study on galaxy detection and shape classification using topometric clustering algorithms. We first use the DBSCAN algorithm to extract, from CCD frames, groups of adjacent pixels with significant fluxes and we then apply the DENCLUE algorithm to separate the contributions of overlapping sources. The DENCLUE separation is based on the localization of pattern of local maxima, through an iterative algorithm which associates each pixel to the closest local maximum. Our main classification goal is to take apart elliptical from spiral galaxies. We introduce new sets of features derived from the computation of geometrical invariant moments of the pixel group shape and from the statistics of the spatial distribution of the DENCLUE local maxima patterns. Ellipticals are characterized by a single group of local maxima, related to the galaxy core, while spiral galaxies have additional ones related to segments of spiral arms. We use two different supervised ensemble classification algorithms, Random Forest, and Gradient Boosting. Using a sample of ~ 24000 galaxies taken from the Galaxy Zoo 2 main sample with spectroscopic redshifts, and we test our classification against the Galaxy Zoo 2 catalog. We find that features extracted from our pipeline give on average an accuracy of ~ 93%, when testing on a test set with a size of 20% of our full data set, with features deriving from the angular distribution of density attractor ranking at the top of the discrimination power.