350 research outputs found

    A review on the formation of heteronuclear cold molecules

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    Is the characterization of biological systems as complex systems in the mathematical sense a fruitful assertion? In this paper we argue in the affirmative, although obviously we do not attempt to confront all the issues raised by this question. We use the fly's visual system as an example and analyse our experimental results of one particular neuron in the fly's visual system from this point of view. We find that the motion-sensitive ‘H1’ neuron, which converts incoming signals into a sequence of identical pulses or ‘spikes’, encodes the information contained in the stimulus into an alphabet composed of a few letters. This encoding occurs on multilayered sets, one of the features attributed to complex systems. The conversion of intervals between consecutive occurrences of spikes into an alphabet requires us to construct a generating partition. This entails a one-to-one correspondence between sequences of spike intervals and words written in the alphabet. The alphabet dynamics is multifractal both with and without stimulus, though the multifractality increases with the stimulus entropy. This is in sharp contrast to models generating independent spike intervals, such as models using Poisson statistics, whose dynamics is monofractal. We embed the support of the probability measure, which describes the distribution of words written in this alphabet, in a two-dimensional space, whose topology can be reproduced by an M-shaped map. This map has positive Lyapunov exponents, indicating a chaotic-like encoding.FAPESPCNP

    value of mr venography for detection of internal jugular vein anomalies in multiple sclerosis a pilot longitudinal study

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    BACKGROUND AND PURPOSE: CCSVI was recently described in patients with MS. CCSVI is diagnosed noninvasively by Doppler sonography and invasively by catheter venography. We assessed the role of conventional MRV for the detection of IJV anomalies in patients with MS diagnosed with CCSVI and in healthy controls who underwent MRV and Doppler sonography examinations during 6 months. MATERIALS AND METHODS: Ten patients with MS underwent TOF, TRICKS, Doppler sonography, and catheter venography at baseline. They were treated at baseline with percutaneous angioplasty and re-evaluated 6 months9 posttreatment with MRV and Doppler sonography. In addition, 6 healthy controls underwent a baseline and a 6-month follow-up evaluation by Doppler sonography and MRV. RESULTS: At baseline, the sensitivity, specificity, PPV, and NPV of Doppler sonography for detecting IJV abnormalities relative to catheter venography in patients with MS were calculated, respectively, at 82%, 100%, 99%, and 95%. The figures were 99%, 33%, 33%, 99% for TOF and 99%, 39%, 35%, and 99% for TRICKS. Venous anomalies included the annulus, septum, membrane, and malformed valve. No agreement was found between TOF and catheter venography in 70% of patients with MS and between TRICKS and catheter venography in 60% of patients with MS. At follow-up, 50% of the patients with MS presented with abnormalities on Doppler sonography but only 30% were diagnosed with restenosis. CONCLUSIONS: Conventional MRV has limited value for assessing IJV anomalies for both diagnostic and posttreatment purposes

    Purification of a monoclonal antibody using a novel high-capacity multimodal cation exchange nonwoven membrane

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    A high-capacity, multimodal cation exchange (MMC) chromatographic membrane was developed by conjugating a multimodal ligand – 2-mercaptopyridine-3-carboxylic acid (MPCA) – on a polybutylene terepthalate (PBT) nonwoven fabric. The membrane features an equilibrium binding capacity of ≈ 1000 mg of human polyclonal IgG (IgG) per g of membrane and dynamic binding capacities (DBC10%) ranging from 77.5 to 115.1 mg/mL (residence times of 1 and 5 min, respectively); these values are 2-to-3-fold higher than those of commercial MMC adsorbents. The effects of buffer composition, pH, conductivity on the binding behavior of the MMC-MPCA membrane were investigated in detail. As a moderate cation exchange binder, MPCA enables effective protein elution using buffers with mild pH (8.0–9.0) and conductivity (≈13 mS/cm), thus circumventing the harsh conditions often needed in multimodal chromatography. The MMC-MPCA membrane was evaluated for product capture in bind-and-elute mode on a Chinese hamster ovary (CHO) cell culture harvest containing therapeutic monoclonal antibodies, using commercial multimodal (Capto MMC and MX-Trp-650M) and affinity (AF-rProtein A HC-650F) resins as controls. The MMC-MPCA membrane outperformed the multimodal resins in terms of binding capacity as well as clearance of host cell proteins (HCPs) and aggregates. The membrane was then evaluated by polishing the mAb from a Protein A eluate in bind-and-elute mode. The MMC-MPCA membrane reduced the level of high molecular weight components from 11% to 4% and the HCP content from 1319.7 ppm to 48.7 ppm (LRV of 1.4). Most notably, proteomics analysis of the product demonstrated the clearance of a significant fraction of persistent, high-risk HCPs from the Protein A eluate

    Use of Pregnancy Associated Glycoproteins to determine Fetal Age Throughout Gestation

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    The objective of the current study was to determine if a commercially available blood pregnancy test could be modified to detect differences in pregnancy-associated glycoprotein (PAG) concentrations that would be indicative of stage of pregnancy or fetal age

    Semiquantitative analysis of mercury in landfill leachates using double-pulse laser-induced breakdown spectroscopy.

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    Made available in DSpace on 2017-11-02T09:09:43Z (GMT). No. of bitstreams: 1 PROCI17Semiquantitativeanalysisofmercury....pdf: 746927 bytes, checksum: b75c0ae6928400c1c1207ac3be058399 (MD5) Previous issue date: 2017-10-31bitstream/item/165918/1/PROCI-17-Semiquantitative-analysis-of-mercury....pd

    Formation of ultracold RbCs molecules by photoassociation

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    The formation of ultracold metastable RbCs molecules is observed in a double species magneto-optical trap through photoassociation below the ^85Rb(5S_1/2)+^133Cs(6P_3/2) dissociation limit followed by spontaneous emission. The molecules are detected by resonance enhanced two-photon ionization. Using accurate quantum chemistry calculations of the potential energy curves and transition dipole moment, we interpret the observed photoassociation process as occurring at short internuclear distance, in contrast with most previous cold atom photoassociation studies. The vibrational levels excited by photoassociation belong to the 5th 0^+ or the 4th 0^- electronic states correlated to the Rb(5P_1/2,3/2)+Cs(6S_1/2) dissociation limit. The computed vibrational distribution of the produced molecules shows that they are stabilized in deeply bound vibrational states of the lowest triplet state. We also predict that a noticeable fraction of molecules is produced in the lowest level of the electronic ground state

    Use of Pregnancy Associated Glycoproteins to Determine Fetal Age Throughout Gestation in Cattle

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    Objective The objective of the current study was to determine if a commercially available blood pregnancy test could be modified to detect differences in pregnancy-associated glycoprotein (PAG) concentrations to indicate stage of pregnancy or fetal age in cattle. Study Description Previously identified pregnant females were grouped by age (pre-primiparous or multiparous). Blood samples were collected between day 27 and 190 of pregnancy (n = 176 from pre-primiparous and n = 240 from multiparous) and serum was tested in duplicate using a commercially available blood pregnancy test, IDEXX Alertys Pregnancy Test. Procedures were adapted to allow concentrations to fall within the detectible range of the assay. Animals were grouped by parity (pre-primiparous vs multiparous) into 4 gestational groups (group 1 - \u3c 30 days, group 2 - 30 to 90 days, group 3 - 91 to 178 days, and group 4 - \u3e178 days). Data were analyzed using the MIXED procedure of SAS with parity and gestational age in the model. There was an effect of parity, gestational age, and a parity by gestational age interaction (P \u3c 0.01). Pre-primiparous animals had greater concentrations of PAGs compared to multiparous animals. Among pre-primiparous animals, serum PAG concentrations did not differ between gestational age groups 1, 2, or 3 (P \u3e 0.37), but group 4 had greater PAG concentrations than all other groups (P \u3c 0.01). Among multiparous animals, serum PAG concentrations decreased from group 1 to 2 (P \u3c 0.01), and then increased throughout gestation (P \u3c 0.01). Data were then analyzed using the REG procedure in SAS within gestational age group. There was a positive correlation between gestational age and PAG concentrations among both pre-primiparous (P \u3c 0.01; R2 = 0.25) and multiparous (gestational age 30 and greater P \u3c 0.01; R2 = 0.64)

    Use of Sperm In Vitro Capacitation and Flow Cytometry to Estimate Bull Fertility

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    Study Description: Frozen-thawed semen from five bulls previously identified as high (48.1% and 47.7%, bulls A and B, respectively), intermediary (45.5%, bull C) or low (43.1% and 40.7%, bulls D and E, respectively) fertility, based on pregnancy per AI, were evaluated with several laboratory measures. Measures included total motility, sperm plasma membrane integrity (viability), acrosome integrity, reactive oxygen species (ROS), mitochondrial membrane energy potential (mito-potential), zinc signatures (signatures 1 to 4), and CD9 protein populations at pre-wash, post-wash, h 0 (diluted with non-capacitation media), and at 0, 3, 6, and 24 h after dilution with capacitation media and incubation at 37 ºC. Data were analyzed using the GLIMMIX procedure of SAS for repeated measures with bull, time, and the interaction as fixed effects. Bull by time interaction was significant (P ≤ 0.01) for total motility and viability. There tended (P = 0.06) to be a bull by time interaction for zinc signatures 1 + 2 combined. There was a significant effect of bull (P ≤ 0.03) for viability, viable sperm with disrupted acrosome, zinc signatures 1, 2, and 1 + 2, viable CD9- (CD9 negative), and dead CD9+ (CD9 positive). High and intermediary field fertility bulls had greater (P ≤ 0.04) percentages of viable sperm, zinc signature 2, and zinc signature 1 + 2 compared to low fertility bulls. High and intermediary fertility bulls had decreased (P ≤ 0.05) percentage of dead CD9+ compared to low fertility bulls. There was or tended to be a positive correlation between pregnancy per AI and viability (P = 0.10; r = 0.81), zinc signature 2 (P = 0.04; r = 0.89), and zinc signature 1 + 2 (P = 0.10; r = 0.80)
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