An epidemiologic, clinical, and therapeutic study of childhood Guillain-Barré syndrome in Kuwait: is it related to the oral polio vaccine?

We studied Guillain-Barré syndrome, affecting children 12 years old or less, throughout Kuwait, in the period between January 1, 1992, and March 31, 1997. Nineteen children had the diagnostic criteria of Guillain-Barré syndrome, with an overall annual incidence rate of 0.95/100,000 population at risk. Female patients outnumbered male patients with a sex ratio of 1.4:1. There was a clustering of cases in winter and spring and in the year 1996. The disease symptoms were relatively severe in our patients because only 16% (3 of 19) of them were able to walk at the height of their illness, whereas the rest were bed or chair bound or needed assisted ventilation. Two patients had the electrodiagnostic features of axonal neuropathy and both had residual deficits on follow-up, whereas the rest recovered fully. All the patients received intravenous immunoglobulin. The mean time to walk unaided was 23.5 days (range, 2-84 days) after intravenous immunoglobulin and excluding the two patients with axonal neuropathy, and full recovery was achieved in a mean time of 103 days (range, 30-300 days). Contrary to previous studies, we found no correlation between oral polio vaccine administration and Guillain-Barré syndrome in 2 successive years (1995 and 1996) during a nationwide campaign targeting children less than 5 years old.     

Ionization coefficient of monolayer graphene nanoribbon

A semi-analytical model for impact ionization coefficient of graphene nanoribbon (GNR) is presented. The model is derived by calculating probability of electrons reaching ionization threshold energy E_t and the distance travelled by electron gaining E_t. In addition, ionization threshold energy is semi-analytically modelled for GNR. During modelling, we justify our assumptions using analytical modelling and comparison with simulation. Furthermore, it is shown that conventional silicon models are not valid for calculation of ionization coefficient of GNR. Finally, the profile of ionization is presented using the proposed models and the results are compared with that of silicon.     

Oxidation of alcohols with tert-butylhydroperoxide catalyzed by Mn (II) complexes immobilized in the pore channels of mesoporous hexagonal molecular sieves (HMS)

The oxidation of alcohols with tert-butylhydroperoxide (TBHP), in the presence of Mn²⁺ complexes immobilized in the pore channels of mesoporous hexagonal molecular sieves (HMS), were investigated. It was found that immobilized [Mn(bpy)₂]²⁺/HMS is an efficient catalyst for the oxidation of alcohols such as benzyl alcohol, n-hexanol and cyclohexanol. The effects of reaction time, amount of Mn²⁺ in the catalyst, type of substrates and oxidants in this catalysis system were investigated. At optimum conditions, TBHP is more efficient oxidant with respect to H₂O₂. Following order has been observed for the percentage of conversions of alcohols: benzylic >1° >2°.     

Synthesis, characterization and electrical resistivity of graphite bi-intercalation compounds G-FeCl3-MCl3 (M = Al, Ga, In) and the related binaries

We present new chemical, crystallographic and electrical conductivity data concerning the title compounds. It is found that the axis repeat distances of the bi-intercalation compounds (GBC) are almost identical to the sum of the interplanar distances of the associated binary compounds. The basal plane resistivity ρ_a decreases upon intercalation of the second halide into the stage two, binary host: ρ_a 5 ± 1 μΩ cm at 295 K and for the GaCl₃₋ and AlCl₃-containing GBC. The axis resistivity possesses a positive temperature coefficient for all compounds examined except the 4th stage FeCl₃ GIC. The room temperature anisotropy is 10⁶ for 1st and 4th stage GaCl₃ GIC as for low stage AsF₅ materials. Chemically determined values of the charge transfer are about twice as great as those evaluated from analysis of the C-C bond distances.     

Fault detection in analogue circuits using hybrid evolutionary algorithm and neural network

With the development of analog integrated circuits technology and due to the complexity, and various types of faults that occur in analog integrated circuits, fault detection is a new idea, has been studied in recent decades. In this paper a three amplifier state variable filter is used as circuit under test (CUT) and, a hybrid neural network is proposed for soft fault diagnosis of the CUT. Genetic algorithm (GA) has the powerful ability of searching the global optimal solution, and back propagation (BP) algorithm has the feature of rapid convergence on the local optima. The hybrid of two algorithm will improve the evolving speed of neural network. GA-BP scheme adopts GA to search the optimal combination of weights in the solution space, and then uses BP algorithm to obtain the accurate optimal solution quickly. Experiment results show that the proposed GA-BP scheme is more efficient and effective than BP algorithm.     

Measurement of the magnetic fields of high-voltage substations (230 kV) in Tehran (Iran) and comparison with the ACGIH threshold limit values

Measurements were made according to IEEE standard 644-1994 at a height of 1 m above floor level. It is concluded that none of the measurements exceeded the ACGIH threshold limit value. Among all control rooms the highest measured density amount is 0.69 μT in the control room of Ozgol substation and the lowest is 0.2 μT in the post of Shahid Firouzi. The control room of Ozgol substation is located in the second floor and bus-bars are located at a short distance from the window on the east, and so the highest recorded magnetic field is measured in this control room. Among all switchgear parts the highest amount 9.15 μT is measured in Kan substation. None of the measurements exceeded the ACGIH threshold limit value.     

Sequencing Batch Reactor (SBR) for the removal of Hg2+ and Cd2+ from synthetic petrochemical factory wastewater

Petrochemical factories which manufacture vinyl chloride monomer and poly vinyl chloride (PVC) are among the largest industries which produce wastewater contains mercury and cadmium. The objective of this research is to evaluate the performance of a lab-scale Sequencing Batch Reactor (SBR) to treat a synthetic petrochemical wastewater containing mercury and cadmium. After acclimatization of the system which lasted 60 days, the SBR was introduced to mercury and cadmium in low concentrations which then was increased gradually to 9.03±0.02 mg/L Hg and 15.52±0.02 mg/L Cd until day 110. The SBR performance was assessed by measuring Chemical Oxygen Demand, Total and Volatile Suspended Solids as well as Sludge Volume Index. At maximum concentrations of the heavy metals, the SBR was able to remove 76-90% of Hg(2+) and 96-98% of Cd(2+). The COD removal efficiency and MLVSS (microorganism population) in the SBR was affected by mercury and cadmium concentrations in influent. Different species of microorganisms such as Rhodospirilium-like bacteria, Gomphonema-like algae, and sulfate reducing-like bacteria were identified in the system. While COD removal efficiency and MLVSS concentration declined during addition of heavy metals, the appreciable performance of SBR in removal of Hg(2+) and Cd(2+) implies that the removal in SBR was not only a biological process, but also by the biosorption process of the sludge.     

Improvement of performance of polyamide reverse osmosis membranes using dielectric barrier discharge plasma treatment as a novel surface modification method

In this research, surface modification of aromatic polyamide thin film composite (TFC) reverse osmosis (RO) membranes was carried out using dielectric barrier discharge (DBD) plasma treatment to improve the performance and fouling resistance of prepared RO membranes. First, polyamide TFC RO membranes were synthesized via interfacial polymerization of m‐phenylenediamine and trimesoyl chloride monomers over microporous polysulfone support membrane. Next, the DBD plasma treatment with 15 s, 30 s, 60 s, and 90 s duration was used for surface modification. The surface properties of RO membranes were characterized by attenuated total reflectance Fourier transform infrared spectroscopy (ATR‐FTIR), SEM, AFM, and contact angle measurements. The ATR‐FTIR results indicated that DBD plasma treatment caused hydrogen bonding on the surface of RO membranes. Also, the contact angle measurement showed that the hydrophilicity of the membranes was increased due to DBD plasma treatment. The changes in the membranes surface morphology indicated that the surface roughness of the membranes was increased after surface modification. In addition, it was found that the DBD plasma treatment increased the water permeation flux significantly and enhanced sodium chloride (NaCl) salt rejection slightly. Moreover, the filtration of bovine serum albumin revealed that the antifouling properties of the modified membranes had been improved. POLYM. ENG. SCI., 59:E468–E475, 2019. © 2018 Society of Plastics Engineers