Intellectual deficits after transient tyrosinemia in the term neonate

An analysis was made of the obstetric history of 1,360 patients who were delivered in 1971. It involved 3,185 pregnancies. The aim of the study was to evaluate the risk of spontaneous termination of the pregnancy, worked out from its demographic aspect. Several ideas are worthy of consideration. The risk of spontaneous intra-uterine death is cumulative, sharply increased by a repetition of such cessation of pregnancy. The same patients often undergo intentional abortion repeatedly. The respective risks of spontaneous and provoked interruption of pregnancy have been studied in greater detail as a function of parity.     

Analysis of organoselenium compounds in human urine using active carbon and chemically modified silica sol-gel surface-assisted laser desorption/ionization high-resolution time-of-flight mass spectrometry

Laser desorption/ionization time-of-flight mass spectra of three thermally labile low molecular weight organoselenium compounds (selenomethionine, selenoethionine, trimethylselenonium iodide) in human urine matrix have been obtained by using surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS). Four active layers, active carbon, silica sol-gel, and silica sol-gel impregnated with crown ether and with active carbon, were deposited on three different support substrates: (i) microscope slide coverslips; (ii) Al foil; and (iii) Cu tapes. Primarily protonated molecular ions and alkali metal adducts were observed in the mass spectra. A mixed-silica sol-gel and active carbon substrate active layer gave the best signal response for all compounds. Sol-gel substrates offered very clean backgrounds compared to the pure active carbon layers; however, the mass spectral signal intensities acquired were substantially lower for the sol-gel surfaces than those of the pure active carbon under the same conditions. Cu tape and Al foil support materials gave strong mass spectra of molecular ions and alkali metal molecular ion adducts, with lower Na and K adducts found with the Cu tape than with Al foil. Glass coverslips gave no response under all experimental conditions examined. Aerosol deposition was used to prepare SALDI substrates to avoid the localized "sweet spot" phenomenon encountered in conventional SALDI substrate preparation. Various nebulizers were examined and found to be effective in producing SALDI films with controlled and reproducible thicknesses. We were able to obtain exact mass identification of all three selenium species by high-resolution TOF-MS. To the best of our knowledge, this is the first time low molecular weight organoselenium compounds have been identified by SALDI-high-resolution TOF-MS.     

Flavonol glycosides and flavonol glucoside gallates from Peltophorum africanum

In this study of interactions occurring within the heart, isolated superfused strips of rabbit atria, containing the sinoatrial (s.a.) node, were subjected to sinusoidal subthreshold current pulses of varied frequencies and intensities. A.C. current from an R.C. oscillator was applied through a Grass stimulation isolation unit, push-pull connection, and non-polarizing (Ag-AgCl-KCl-Tyrode Agar-Agar) electrodes. A Grass polygraph and tachometer were used to record the applied pulses and nodal firing rates; simultaneous magnetic tape recordings were obtained and used for data analysis. Suction electrode recordings and oscilloscope displays were used to determine how the cyclic impulses affected cellular activity. The s.a. nodal rhythm was modified by subthreshold A.C. current applications; when frequencies were low, firing rates of the node were modulated by the A.C. and mean rates were reduced. As frequencies were progressively increased, slow waxings and wanings in heart rate were produced. These periodic fluctuations were not readily correlated with either the A.C. frequency nor the intrinsic nodal rate, but were representative of the difference between the two. As applied current frequency neared the pacemaker's intrinsic rate, a synchronization occurred and the discharges locked in at a specific phase of the applied current alternation. This synchronization maintained during slight further increases in A.C. frequency but above a critical rate this relationship broke down and the waxing and wanings in frequency of pacemaker rate again developed. It was concluded that pacemaker action of the s.a. node is effected by integration of cellular activity through electron coupling.     

Symmetric Orthogonal Complex-Valued Filter Bank Design by Semidefinite Programming

A new design method for complex-valued two-channel finite impulse response (FIR) filter banks with both orthogonality and symmetry properties is developed. Based on a novel linear matrix inequality (LMI) characterization of trigonometric curves, the optimal design of perfect-reconstruction filter banks is cast into a semidefinite programming (SDP) problem. The dimension of the resulting SDP problem is further reduced by exploiting convex duality. Consequently, the globally optimal solution can be found for any practical filter length and desired regularity order.     

Dyna-Q-based vector direction for path planning problem of autonomous mobile robots in unknown environments

Reinforcement learning (RL) is a popular method for solving the path planning problem of autonomous mobile robots in unknown environments. However, the primary difficulty faced by learning robots using the RL method is that they learn too slowly in obstacle-dense environments. To more efficiently solve the path planning problem of autonomous mobile robots in such environments, this paper presents a novel approach in which the robot’s learning process is divided into two phases. The first one is to accelerate the learning process for obtaining an optimal policy by developing the well-known Dyna-Q algorithm that trains the robot in learning actions for avoiding obstacles when following the vector direction. In this phase, the robot’s position is represented as a uniform grid. At each time step, the robot performs an action to move to one of its eight adjacent cells, so the path obtained from the optimal policy may be longer than the true shortest path. The second one is to train the robot in learning a collision-free smooth path for decreasing the number of the heading changes of the robot. The simulation results show that the proposed approach is efficient for the path planning problem of autonomous mobile robots in unknown environments with dense obstacles.     

CAR-Miner: An efficient algorithm for mining class-association rules

Building a high accuracy classifier for classification is a problem in real applications. One high accuracy classifier used for this purpose is based on association rules. In the past, some researches showed that classification based on association rules (or class-association rules – CARs) has higher accuracy than that of other rule-based methods such as ILA and C4.5. However, mining CARs consumes more time because it mines a complete rule set. Therefore, improving the execution time for mining CARs is one of the main problems with this method that needs to be solved. In this paper, we propose a new method for mining class-association rule. Firstly, we design a tree structure for the storage frequent itemsets of datasets. Some theorems for pruning nodes and computing information in the tree are developed after that, and then, based on the theorems, we propose an efficient algorithm for mining CARs. Experimental results show that our approach is more efficient than those used previously.     

A Comprehensive Approach for Estimating Hydraulic Quantities in a Multi-branched Estuarine System

Despite many previous investigations, there is no theoretically justifiable equation to determine the freshwater discharge, tidal velocity, and salinity in a complex estuary that contains several branches. In this study, the longitudinal distributions of freshwater and salinity concentration in multi-branched estuaries are investigated using a mathematical model, considering the energy balance by frictional head loss and the salt balance by diffusion and advection in a one-dimensional steady-state condition. We attempt to obtain the time-mean freshwater discharge rate quantitatively at a junction where the main flow separates into two branches. The salinity distribution along each branch is calculated by following the dispersion coefficient equation previously proposed for a single estuary. The salinity field is divided into the near-coast region and the upstream region, because in each segment the inland velocity varies according to the tidal flux. For computing the tidal velocity, we propose the Burgers equation and the Hoph-Cole transformation. The theoretical results obtained by these equations were found to be in good agreement with a set of observed data in the Red River estuary system.     

Mechanism of zeolite A nanocrystal growth from colloids at room temperature

The formation and growth of crystal nuclei of zeolite A from clear solutions at room temperature were studied with low-dose, high-resolution transmission electron microscopy in field emission mode and with in situ dynamic light scattering. Single zeolite A crystals nucleated in amorphous gel particles of 40 to 80 nanometers within 3 days at room temperature. The resulting nanoscale single crystals (10 to 30 nanometers) were embedded in the amorphous gel particles. The gel particles were consumed during further crystal growth at room temperature, forming a colloidal suspension of zeolite A nanocrystals of 40 to 80 nanometers. On heating this suspension at 80 degrees C, solution-mediated transport resulted in additional substantial crystal growth.