Spontaneous thrombosis of an unruptured anterior communicating artery aneurysm. An unusual cause of ischemic stroke

BACKGROUND: Stroke caused by spontaneous thrombosis of an unruptured intracranial aneurysm is a rare event. CASE DESCRIPTION: A 66-year-old woman experienced a transient ischemic attack and cerebral infarctions due to spontaneous thrombosis of an unruptured anterior communicating artery aneurysm. Extension of thrombus into both anterior cerebral arteries and the left middle cerebral artery, resulting in ischemic infarction in all three vascular territories, was diagnosed by CT scanning, MRI, and cerebral angiography and confirmed at autopsy. CONCLUSIONS: This case illustrates a rare complication of an unruptured saccular aneurysm with neuroimaging and pathological correlation. Morphological and hemodynamic factors that may have precipitated aneurysm thrombosis are discussed with reference to experimental models.     

A 0.5-GHz to 2.5-GHz PLL With Fully Differential Supply Regulated Tuning

This paper describes a wide-range clock generation phase-locked loop (PLL) incorporating several features that make it suitable for integration in highly scaled processes. A fully differential supply regulated tuning scheme is used to combat power supply noise. The charge pump uses a resistor rather than an active current source to define the pumping current in order to reduce the charge pump flicker noise. Fabricated in a 0.18-mum CMOS process, the PLL occupies 0.15 mm² die area and achieves a frequency range of 0.5 to 2.5 GHz. When operating at 2.4 GHz, the power consumption is 14 mA from a 1.8-V supply while the jitter is 2.36 ps rms     

Analysis of charge-pump phase-locked loops

In this paper, we present an exact analysis for third-order charge-pump phase-locked loops using state equations. Both the large-signal lock acquisition process and the small-signal linear tracking behavior are described using this analysis. The nonlinear state equations are linearized for the small-signal condition and the z-domain noise transfer functions are derived. A comparison to some of the existing analysis methods such as the impulse-invariant transformation and s-domain analysis is provided. The effect of the loop parameters and the reference frequency on the loop phase margin and stability is analyzed. The analysis is verified using behavioral simulations in MATLAB and SPECTRE.     

THE MANUFACTURE AND TREATMENT OF GLASS MELTING POTS*

Manufacture of glass melting pots .—The raw materials used, the methods of grinding and mixing the raw clay and grog, and the way in which pots are built and dried are briefly described for the purpose of impressing glass makers with the amount of labor and care involved. At present only one grade of pot is made; but the difficulty of getting a pot suitable for all kinds of glass suggests the desirability of making special grades of pot for use with specified kinds of glass. Proper treatment of pots by the glass maker .—The authors emphasize the importance of gently handling pots and of storing them in a warm and dry place. The precautions to be taken in preheating pots in arches are discussed at length for this is the critical period in the life of the pot. The batch should be properly crushed and mixed and should either be preheated or loaded in gradually; and the furnace temperature should be carefully regulated. It is particularly urged that the technical treatment of pots in the glass be entrusted to a man trained in ceramics and physical chemistry. Arches for heating glass melting pots .—After discussing the usual design the authors suggest improvements as to fire box locations, construction of walls and door, etc.     

Immunocytochemical demonstration of neuropeptides in the peripheral nervous system of the roundworm Ascaris suum (Nematoda, Ascaroidea)

The localisation and distribution of neuropeptides in the peripheral nervous system of the pig roundworm Ascaris suum have been determined by an indirect immunofluorescence technique in conjunction with confocal microscopy. Of the 31 antisera tested, immunostaining was obtained only with antisera to peptide YY (PYY), pancreatic polypeptide (PP) and FMRFamide. Immunostaining for PYY and FMRFamide was evident in the amphidial and papillary ganglia associated with the anterior nerve ring and in the nerves from these ganglia that terminated in sensory receptors within the buccal lips of the parasite. The only peptide immunoreactivity (IR) observed in the reproductive system of either sex was that evident in the nerve supply to the distal region of the vagina in the female worm. It took the form of a well-developed plexus of parallel nerve fibres, cross-connectives and looped commissures. The nerve net diminished in the more proximal region of the vagina. PP-IR was less intense than that for PYY and FMRFamide and was more restricted in distribution, being confined to a small number of nerve fibres in the nerve supply to the vagina; it did not occur in the nerves supplying the anterior sensory receptors. The possible roles of neuropeptides in the sensory and reproductive biology of nematodes are discussed.     

The physiological roles of dietary fibre

The term dietary fibre (indigestible carbohydrates of plant origin) encompasses a range of divergent compounds that differentially affect numerous important gastrointestinal and systemic bodily processes.     

The application of an ether cleavage technique to a study of the biodegradation of a linear alcohol ethoxylate nonionic surfactant

The biodegradation of a linear alcohol ethoxylate nonionic surfactant (C₁₂-C₁₅, eo₉) was studied by gas chromatography of the alkyl bromides produced by acid cleavage of the surfactant ether linkages with hydrogen bromide. In laboratory cultures and in a lake environment, a conventional method showed rapid loss of surface activity. The gas chromatographic method revealed a rapid degradation of the surfactant alkyl moiety but a slow and incomplete removal of the polyethoxylate moiety.     

Ligand requirements for Ca2+ binding to EGF-like domains

Site-specific mutagenesis studies of the first epidermal growthfactor-like (EGF-like) domain of human clotting factor IX suggestthat the calcium-binding site present in this domain (dissociationconstant K_d=1.8 mM at pH 7.5 and ionic strength I=0.15) involvedthe carboxylate residues Asp47, Asp49 and Asp64. To furthercharacterize the ligands required for calcium binding to EGF-likedomains, two new mutations, Asp47 - Asn and Asp49 - Asn, wereintroduced into the domain by peptide synthesis. ¹H-NMR spectroscopywas used to obtain the dissociation constants for calcium bindingto these mutations. Calcium binding to the Asp49- Asn modifieddomain is only mildly affected (K_d=6 mM, I=0.15), whereas bindingto the Asp47- Asn modified domain is severely reduced (K_d=42mM, I=0.15). From these data, it is proposed that the anionicoxygen atoms of the side chains of residues 47 and 64 are essentialfor calcium binding, whereas the side chain ligand for calciumat residue 49 can be a carboxyamide oxygen. As a control, theintroduction of the modification Glu78- Asp in a region of thedomain not believed to be involved in calcium binding had verylittle effect on the K_d for calcium (K_d=2.6 mM, I=0.15). Finally,the effect of an Asp47- Gly substitution found in the naturalhaemophilia B mutant, factor IX_Alabama, was investigated. Thispeptide has a markedly reduced affinity for calcium (K_d=37 mM,I=0.15), suggesting that the defect in factor IX_Alabama is dueto impaired calcium binding to its first EGF-like domain.