Design approach to low-cost process control

The design of a control package for industrial use on small-scale processes is discussed. A modular system is described, made up of intelligent satellite and peripheral controllers plus various cards to provide communication with the industrial plant itself. The design is intended for operators who have little or no experience of computing. It is based on a language called paracode, an interpretive language structured to provide a number of control sequences which can run independently of each other or in parallel. Two applications of the design—a clean-in-place system and a beer-fermentation controller—are used as illustrations.     

Bilateral femoral neck fractures as a complication of myelography

This paper discusses two cases of bilateral subcapital fracture of the proximal femur as a complication of myelography with Conray 60. The literature is reviewed.     

Normal lung function in subjects heterozygous for surfactant protein-B deficiency

OBJECTIVE AND IMPORTANCE: We present a case report of a patient with a left frontal brain abscess. Cultures obtained from the abscess at the time of surgery were identified as dental flora known to establish a synergistic relationship in polymicrobial infections. This type of synergistic relationship makes the clearance of an infection more difficult for an intact immune system. A serum immunoglobulin (Ig) Type A deficiency was identified postoperatively. This immunodeficiency may have contributed to the development of the abscess. CLINICAL PRESENTATION: The patient presented with headaches and photophobia. Computed tomography of the head performed with intravenously administered contrast demonstrated a left frontal brain abscess. INTERVENTION: The patient was operated on through a left frontal approach, carefully avoiding the frontal sinus. The abscess was aspirated, and the patient was treated with intravenous antibiotics for several weeks. Postoperatively, the patient did well. There were no signs of enhancement on follow-up computed tomographic scans at 7 and 12 months postoperatively. CONCLUSION: Through a comprehensive immunological workup, an IgA deficiency was identified postoperatively. Although the deficiency of a single type of Ig may be asymptomatic, complications from recurrent or chronic bacterial infections may occur. The deficiency of IgA, combined with a synergistic polymicrobial infection, contributed to the development of an intracranial abscess. A patient presenting with a brain abscess without any predisposing medical history should be evaluated for an underlying immune deficiency.     

Huntingtin-associated protein 1 (HAP1) interacts with the p150Glued subunit of dynactin

Huntington's disease (HD) is an inherited neurodegenerative disease caused by expansion of a polyglutamine repeat in the HD protein huntingtin. Huntingtin's localization within the cell includes an association with cytoskeletal elements and vesicles. We previously identified a protein (HAP1) which binds to huntingtin in a glutamine repeat length-dependent manner. We now report that HAP1 interacts with cytoskeletal proteins, namely the p150 Glued subunit of dynactin and the pericentriolar protein PCM-1. Structural predictions indicate that both HAP1 and the interacting proteins have a high probability of forming coiled coils. We examined the interaction of HAP1 with p150 Glued . Binding of HAP1 to p150 Glued (amino acids 879-1150) was confirmed in vitro by binding of p150 Glued to a HAP1-GST fusion protein immobilized on glutathione-Sepharose beads. Also, HAP1 co-immunoprecipitated with p150 Glued from brain extracts, indicating that the interaction occurs in vivo . Like HAP1, p150 Glued is highly expressed in neurons in brain and both proteins are enriched in a nerve terminal vesicle-rich fraction. Double label immunofluorescence experiments in NGF-treated PC12 cells using confocal microscopy revealed that HAP1 and p150 Glued partially co-localize. These results suggest that HAP1 might function as an adaptor protein using coiled coils to mediate interactions among cytoskeletal, vesicular and motor proteins. Thus, HAP1 and huntingtin may play a role in vesicle trafficking within the cell and disruption of this function could contribute to the neuronal dysfunction and death seen in HD.     

The spontaneous gating activity of OmpC porin is affected by mutations of a putative hydrogen bond network or of a salt bridge between the L3 loop and the barrel

Porins are trimeric channel-forming proteins of the outer membrane of Escherichia coli. Each subunit contains 16 beta-strands forming a transmembrane beta-barrel whose pore is constricted by the third extracellular loop (L3). We investigated the effects of site-directed mutations at two critical regions of the OmpC porin: (i) the D315A mutation targets a key component of a putative hydrogen bond network linking the L3 loop to the adjacent barrel wall and (ii) the D118Q, R174Q and R92Q mutations target putative salt bridges at the root of the L3 loop. We purified the outer membrane fractions obtained from each mutant and reconstituted them in liposomes suitable for electrophysiology. Patch clamp experiments showed that the frequency of spontaneous transitions between open and closed states is increased in the D315A, D118Q and R92Q mutants but unchanged in the R174Q mutant. These transitions are not driven by transmembrane voltage changes and represent the thermal oscillations between functionally distinct conformations. The asymmetric voltage-dependent inactivation of the channels is not affected by the mutations, however, suggesting different molecular mechanisms for the spontaneous and voltage- dependent gating processes. We propose that the positioning or flexibility of the L3 loop across the pore, as governed by the putative hydrogen-bond network and a salt bridge, play a role in determining the frequency of spontaneous channel gating.