Mitogen-activated protein kinases (Erk1,2) phosphorylate Lys-Ser-Pro (KSP) repeats in neurofilament proteins NF-H and NF-M

Mammalian neurofilament proteins, particularly midsized (NF-M) and heavy (NF-H) molecular weight neurofilament proteins, are highly phosphorylated in axons. Neurofilament function depends on the state of phosphorylation of the numerous serine/threonine residues in these proteins. Most phosphorylation occurs in the lys-ser-pro (KSP) repeats in the C-terminal tail domains of NF-H and NF-M. In our previous study, cyclin-dependent kinase 5 (cdk5) was shown to phosphorylate specifically the KSPXK repeats in rat NF-H. Because 80% of the repeats are of the KSPXXXK type, it was of interest to determine which kinase phosphorylates these motifs. Using a synthetic KSPXXXK peptide to screen for a specific kinase, we fractionated rat brain extracts by column chromatography and identified extracellular signal-regulated kinase (Erk2) activated by an upstream activator, the mitogen-activated protein kinase kinase MAPKK (MEK), by Western blot analysis, sequence identification, and inhibition by a specific MEK inhibitor (PD 98059). The fraction containing Erk2, as well as bacterially expressed Erk1 and Erk2, phosphorylated all types of KSP motifs in peptides (KSPXK, KSPXXK, KSPXXXK, and KSPXXXXK) derived from NF-M and NF-H. They also phosphorylated an expressed 24 KSPXXXK repeat NF-H polypeptide, an expressed NF-H as well as dephosphorylated native rat NF-H, and NF-M proteins with accompanying decreases in their respective electrophoretic mobilities. A comparative kinetic study of Erk2 and cdk5 phosphorylation of KSPXK and KSPXXXK peptides revealed that, in contrast to cdk5, which phosphorylated only the KSPXK peptide, Erk2 could phosphorylate both. The preferred substrate for Erk2 was KSPXXXK peptide. The MEK inhibitor PD 98059 also inhibited phosphorylation of NF-H, NF-M, and microtubule-associated protein (MAP) in primary rat hippocampal cells and caused a decrease in neurite outgrowth, suggesting that Erk1,2 may play an important role in neurite growth and branching. These data suggest that neuronal Erk1 and Erk2 are capable of phosphorylating serine residues in diverse KSP repeat motifs in NF-M and NF-H.     

Moderate ovarian hyperstimulation syndrome complicated by deep cerebrovascular thrombosis

This report describes two cases that developed moderate ovarian hyperstimulation syndrome (OHSS) without evidence of haemoconcentration. Both patients developed serious cerebrovascular thrombosis resulting in hemiparesis, and recovered after treatment with anticoagulants. This report emphasizes that other factors may contribute to vascular thrombosis, and illustrates that cerebrovascular accidents may complicate even moderate OHSS.     

Solar box cookers: Towards a decentralized sustainable energy strategy for sub-Saharan Africa

The continued economic decline of sub-Saharan Africa, and the African energy crisis in particular, have received considerable attention in recent literature. Little attention, however, has been given to the assessment of solar power as an environmentally sound and economically viable energy strategy. Considering the increasing fuelwood scarcity and debt incurred through petroleum imports, solar energy provides a welcome alternative to traditional biomass and fossil fuel energy sources. Research and development in solar energy has concentrated primarily on highly technical, capital intensive applications, leaving possibilities for small scale utilizations unexplored. This paper argues for small scale, decentralized development of solar power as a sustainable household fuel source for sub-Saharan Africa. Domestic cooking constitutes more than 60% of total energy use in the region and consumes scarce time, labor, income, and natural resources. Thus, the appropriate management of fuel and energy resources in the residential sector is crucial for significant development. This paper examines the economic viability of solar box cookers (SBCs), their costs and benefits both on the household and community levels, and how they may contribute to economic development. In arguing for the implementation of SBCs, policy implications in terms of financing and a comprehensive energy plan geared towards sustainable development are also presented.     

Meta-Heuristic Algorithms for Hydrologic Frequency Analysis

Meta-heuristic algorithms, such as the genetic algorithm and ant colony optimization, have received considerable attention in recent years due to their higher ability for solving difficult engineering optimization problems. This paper employs these techniques for estimating parameters of commonly used flood frequency distributions, and compares them with some conventional methods such as maximum likelihood, moments and probability weighted moments using annual maximum discharge data of 14 rivers from East-Azarbaijan, Iran. The results indicate that both the genetic algorithm and ant colony optimization are suitable parameter estimation alternatives. Also, the results of Monte Carlo simulation for various sample sizes, ranging from 20 to 100, demonstrate that the meta-heuristic algorithms yield accurate quantile estimates.     

Repair of coarctation with resection and extended end-to-end anastomosis

BACKGROUND: Our surgical strategy for infant coarctation changed from subclavian flap aortoplasty to resection with extended end-to-end anastomosis in 1991. The purpose of this review was to evaluate the results of that strategy. METHODS: From 1991 through 1997, 55 infants underwent repair of coarctation of the aorta using resection with extended end-to-end anastomosis. Isolated coarctation of the aorta was present in 26 patients, 20 patients had a ventricular septal defect, and 9 patients had other associated intracardiac lesions. Mean age at surgery was 0.20+/-0.24 years (median, 21 days). In 34 patients (62%), arch reconstruction was performed through a left thoracotomy. Twenty patients (36%) had median sternotomy with simultaneous repair of coarctation of the aorta and intracardiac repair of associated lesions. One patient had recoarctation repair through a median sternotomy. All coarctation and ductal tissue was resected and the anastomosis was constructed starting opposite the left carotid artery with running polypropylene suture. RESULTS: There was one early death 26 days after coarctation of the aorta and ventricular septal defect repair in a child on extracorporeal membrane oxygenation for meconium aspiration and 2 late deaths owing to pneumonia and pulmonary hypertension (1) and interventricular hemorrhage (1). There were no instances of paraplegia. Follow-up in survivors ranges from 10 to 76 months (mean, 39.8+/-17.2 months). Recoarctation has developed in 2 patients, who have had successful balloon dilation 6 and 14 months after the operation. This yields a low recoarctation rate of 3.6%. CONCLUSIONS: Resection with extended end-to-end anastomosis yields a low mortality and particularly a low recoarctation rate and is our procedure of choice for infants with coarctation of the aorta.     

North America's electricity infrastructure: are we ready for more perfect storms?

With the tragic events of 9/11 permanently etched in our minds, the massive 14 August power outage evoked eerie reminders of what shook our world 2 years ago. While preliminary reports indicate that there was no apparent evidence of terrorism, the cascading blackouts were a sudden illumination of our electricity infrastructure's vulnerable condition. This infrastructure affects us all - are we prepared for future storms?.     

Highlights of statistical signal and array processing

The Statistical Signal and Array Processing Technical Committee (SSAP-TC) deals with signals that are random and processes an array of signals simultaneously. The field of SSAP represents both solid theory and practical applications. Starting with research in spectrum estimation and statistical modeling, study in this field is always full of elegant mathematical tools such as statistical analysis and matrix theory. The area of statistical signal processing expands into estimation and detection algorithms, time-frequency domain analysis, system identification, and channel modeling and equalization. The area of array signal processing also extends into multichannel filtering, source localization and separation, and so on. This article represents an endeavor by the members of the SSAT-TC to review all the significant developments in the field of SSAP. To provide readers with pointers for further study of the field, this article includes a very impressive bibliography-close to 500 references are cited. This is just one of the indications that the field of statistical signals has been an extremely active one in the signal processing community. The article also introduces the recent reorganization of three technical committees of the Signal Processing Society     

Synthesis,Characterization and Investigation of Different Properties of Three Novel Thiourea-Based Non-ionic Surfactants

Three novel thiourea‐based non‐ionic surfactants, 3‐decanoyl‐1,1‐diphenylthiourea, 3‐dodecanoyl‐1,1‐diphenylthiourea and 1,1‐diphenyl‐3‐tetradecanoylthiourea were synthesized from carbonyl chlorides, potassium thiocyanate and amines in high yield. The synthesized compounds were characterized by different techniques like ¹H NMR, ¹³C NMR, FTIR and UV‐Visible spectrophotometry. These surfactants are soluble in nonpolar and polar organic solvents and resist solubility in water due to the presence of thiourea group. Electronic absorption spectroscopy was used to evaluate their critical micelle concentration (CMC) in different solvents. The CMC was found to decrease with increase in hydrophobic carbon chain length as expected. Moreover, the effect of pH on their spectral transition was investigated and the two peaks were found to merge in highly alkaline conditions.     

Application of Taguchi Method for Characterization of Corrosion Behavior of TiO2 Coating Prepared by Sol‐Gel Dipping Technique

Titanium oxide (TiO₂) nanoparticle coatings were deposited on the 316L stainless steel substrates by sol‐gel method. The morphology, structure, and corrosion resistance of the coating were analyzed using SEM, AFM, X‐ray diffraction, and electrochemical techniques. The deposition parameters employed to realize the anticorrosion performance including calcinations temperature, polyethylene glycol (PEG) content, pH value, and number of dipping cycles were investigated. Taguchi statistical experiments were carried out to determine the influence of the deposition variables on anticorrosion properties and optimal conditions. The results indicated that a higher anticorrosion performance of TiO₂ films could be achieved using 1 g of PEG in a sol with pH in range of 7–9, six cycles of dipping, and calcination temperature at 400°C. The Tafel polarization measurements indicate that i_corr value decreases about 200 times and the R_corr value increases around 57 times compared with uncoated 316L stainless steel.