Devitrification of sodium disilicate glass: a NMR study

Several crystallographically non-equivalent structures of sodium disilicate are known to exist. Successive heat treatments of the sodium disilicate glasses show -, -, - and -Na2Si2O5 as the devitrification products, depending upon the nature of heat treatment. At higher temperatures and for longer treatment times, only -Na2Si2O5 is observed but for intermediate temperature and time, and forms of the polymorphs are produced. For shorter times, all the polymorphs are formed. The results are verified using magic angle spinning nuclear magnetic resonance as well as X-ray diffraction. A way of estimating the unknown Si–O–Si mean bond angle of the polymorphs, with the help of the known values of the angles, is also presented.     

Somatic mosaicism in a patient with neurofibromatosis type 1

Using loss of heterozygosity analysis, a method designed to detect moderate to large gene deletions, we have identified a new-mutation neurofibromatosis type 1 (NF1) patient who is somatically mosaic for a large maternally derived deletion in the NF1 gene region. The deletion extends at least from exon 4 near the 5' end of the gene to intron 39 near the 3' end. The gene-coding region is, therefore, mostly or entirely deleted, encompassing a loss of > or = 100 kb. We hypothesize that the deletion occurred at a relatively early developmental timepoint, since signs of NF1 in this patient are not confined to a specific body region, as seen in "segmental" NF, and since both mesodermally and ectodermally derived cells are affected. This report provides the first molecular evidence of somatic mosaicism in NF1 and, taken together with a recent report of germ-line mosaicism in NF1, adds credence to the concept that mosaicism plays an important role in phenotypic and genetic aspects of NF1 and may even be a relatively common phenomenon.     

Influence of hypertonic saline solution infusion on defibrillation efficacy

BACKGROUND: Transplantation of lung allografts from the same donor into 2 recipients ("twinning") provides an opportunity to study recipient and donor factors that influence early allograft function. METHODS: Twenty-seven pairs of recipients were identified and evaluated using multivariate logistic regression analysis (p < 0.05). Four measures of early graft function were analyzed: alveolar-arterial gradient in the operating room, first alveolar-arterial gradient in the intensive care unit, alveolar-arterial gradient at 24 hours, and days of mechanical ventilation. RESULTS: Analysis of the pooled data without regard to pairing showed that alveolar-arterial gradient in the operating room was influenced by donor age, length of donor hospitalization, recipient mean pulmonary artery (PA) pressure at unclamping, and transplantation of a left lung. The alveolar-arterial gradient in the intensive care unit was correlated with donor age, donor cause of death, and mean PA pressure on arrival in that unit. Only mean PA pressure remained significant at 24 hours. Days of mechanical ventilation was determined by mean PA pressure on arrival in the intensive care unit, drop in mean PA pressure during operation, and diagnosis of the recipient. In the paired analysis, receiving a left lung, recipient diagnosis (pulmonary hypertension worse than others), and need of cardiopulmonary bypass were significantly associated with immediate graft dysfunction, although these influences did not persist beyond the immediate postoperative period. Donor arterial oxygen tension and time of ischemia were not significant predictors in any analysis. CONCLUSIONS: Immediate allograft function was associated with donor-related characteristics initially, but these lost importance over the ensuing 24 hours. Recipient PA pressure was an immediate and persisting influence. In the analysis of differences in function between the members of each pair, transplantation of the left lung, recipient diagnosis, and cardiopulmonary bypass were identified, but their influence did not persist beyond the first 6 hours.     

Comparison of disability behavior after different sites and types of injury in a workers' compensation population

In this study, an extensive data set from a regional workers' compensation system was analyzed to determine whether particular sites or types of injury were associated with prolonged disability. This data shows a similar pattern of vocational disability for almost all sites and types of injury. A workers' compensation carrier collects data for financial purposes related to insurance, and such data therefore has several serious potential deficiencies when used for clinical research. However, published data on disablement after nonoccupational trauma shows similar patterns of vocational and nonvocational disability, and also shows dependence on severity of injury. In both settings, head injury is associated with greater occupational disability. Because treatment, policy, and medicolegal decisions are based on the impression of "typical disability" for particular sites and types of injury, there is a need for better documentation of post-traumatic disablement in compensation settings and in noncompensation settings. This should include better classification of the cause, type, and severity of the injury, and of the functional outcome in terms of both the resumption of occupational and nonoccupational roles, and of persistence in these roles.     

Strategy, networks and systems in the global translation services market

The globalisation of markets has led to an increased demand for language translation services that support and enable communication between economic partners. For example, technical documents, software systems, business documents and web sites all need to be translated into multiple languages for individual national markets, and the information that they contain changes periodically. This paper sets out a theoretical framework that describes the architectures of business processes within and between separate firms that are used to support the delivery and management of services. This is done by coordinating the fit between externally generated problem complexity, from customers, and the internally generated complexity of different potential network configuration solutions. The theoretical framework is an architecture of how complexity is generated and managed at the different structural levels and across the different processual stages of an industry. A case study of thebigword, a major international translation services company, illustrates how the framework is applied in practice. The case study analyses the implementation of an electronic market platform which enables the coordination of the different stakeholders involved in the translation services market. These stakeholders include translators, translation services companies and their clients in a global business network.     

The Australian Incident Monitoring Study. Oesophageal intubation: an analysis of 2000 incident reports

There were 35 oesophageal intubations in the first 2000 incidents reported to the Australian Incident Monitoring Study (AIMS). These reports confirm existing impressions that misplacement of the endotracheal tube can occur in trained as well as untrained hands, and that auscultation is an unreliable test. On the other hand, the value of capnography is emphasised, with no false positives in the 16 cases in which the instrument was used. There was one false negative. Over the 4 years of the AIMS study, reports have declined in frequency. It is possible that the early detection of oesophageal intubation by capnography has altered its status to the extent that anaesthetists no longer regard it as a "critical" incident. It is highly recommended that the presence of the expected concentration of carbon dioxide in expired air be confirmed by capnography immediately after any endotracheal intubation.     

Development of a scoring system to assess disability in an Italian elderly population. Evaluation of a disability questionnaire

Patients with idiopathic and symptomatic restless legs syndrome (RLS) suffer from "dyskinesia while awake" or "daytime myoclonus" when at rest preceded by sensory symptoms. In order to characterise the RLS either as reflex movement or as voluntary movement we measured movement-related cortical potentials in 5 idiopathic and 8 uraemic RLS patients. Movements from both legs were polygraphically recorded concomitantly with cortical activity 2000 msec before to 500 msec after onset of EMG activity. These data were compared with a voluntary simulation of each patient's movement pattern and with 5 age-matched controls performing dorsiflexion of the right, left and both feet. Cortical activity preceding daytime myoclonus was absent in RLS patients whereas self-initiated leg movements in patients elicited onset times (1180-1380 msec) and amplitudes of Bereitschaftspotential (readiness potential) not significantly different from readiness potentials in control subjects (P > 0.05). Lack of movement-related potentials in myoclonus and/or dyskinesias during daytime in RLS patients is compatible with an involuntary mechanism of induction and points towards a subcortical or spinal origin of RLS.     

Osmotic concentration of polypeptides from hemofiltrate of uremic patients

In order to clarify the interactions between various doses of thiopental and fentanyl in producing "balanced anaesthesia", their effects on consciousness, superficial nociception, and respiration and circulation were studied during N2O+O2 inhalation in connection with the induction of anaesthesia. Altogether 60 patients were studied; the drug combinations used were thiopental 5 mg/kg (TP5), thipental 3 mg/kg (TP3), thiopental 3 mg/kg and fentanyl 0.5 micrograms/kg (TP3F0.5), thiopental 2 mg/kg and fentanyl 1 micrograms/kg (TP2F1), thiopental 1 mg/kg and fentanyl 2 micrograms/kg (TP1F2), and fentanyl 3 micrograms/kg (F3). Five minutes after the i.v. supplementation of N2O+O2 anaesthesia, the depth of anaesthesia and analgesia (antinociception) were evaluated from the eyelid reflex and by pinching an inguinal skin fold. Cardiorespiratory parameters were measured during this study period at 1-min intervals. The balance between antinociception and anaesthesia was closest to optimum in groups TP2F1 and TP2F0.5. In pure thiopental groups, the analgesia was poor; only four patients did not respond to the nociceptive stimulus, whereas in group F3 anaesthesia (disappearance of the eyelid reflex) was obtained in only two patients. The respiratory depression was most pronounced in groups receiving 3, 2 and 1 micrograms/kg fentanyl and weakest in groups where only thiopental was used. Blood pressure decreased in all groups but no statistically significant differences were noted. On the basis of the results it seems obvious that attempts to achieve what is called "balanced anaesthesia" by the supplementation of an N2O+O2 mixture with fentanyl only leads to an unnecessarily prnounced respiratory depression, whereas supplementation with thiopental alone does not offer adequate antinociception.     

The renal factor in the post-traumatic "fluid overload" syndrome

Hypervolemia with hypertension often occurs 36-72 hours following massive blood and fluid replacement for hypovolemic shock. This syndrome of "fluid overload" has been attributed to the rapid intravascular flux of previously sequestered fluid in patients with impaired diuresis. This hypothesis was tested in 35 injured patients who received a mean of 9.3 L of blood and 17.4 L of salt during resucitation. The renal parameters measured soon after resuscitation included: 1) renal clearance of inulin (GFR), para-amino hippurate (ERPF), milliosmoles, sodium, and free water; 2) inulin space, renal vascular resistance (RVR), O2 consumption, renin, renal blood flow (RBF), and response to furosemide. Eighteen patients developed hypertension, hypervolemia, and respiratory insufficiency. When compared to the 17 normovolemic, non-hypertensive patients, the 18 hypervolemic patients had significantly increased RVR, with a significant decrease in RBF despite an increase in plasma volume and cardiac output. Furosemide produced less diuresis and natriuresis in the hypertensive patients. The balance between hypovolemia and "fluid overload" seemed percarious in the hypertensive patients. Peripheral renin and catecholamine levels were normal in both groups. Patients with post-traumatic "fluid overload" appear to have a combination of hypervolemia, respiratory insufficiency, hypertension, increased cardiac output, decreased extracellular fluid space, and decreased renal perfusion. These findings suggest that decreased interstitial fluid space compliance rather than "fluid overload" is the underlying factor leading to respiratory insufficiency. The therapeutic aspects of these findings are discussed.