Radical polymerization of acrylonitrile initiated by α-picolinium p-chlorophenacylid

The radical polymerization of acrylonitrile (AN) with α-picolinium p-chlorophenacylid (α-PCPY) as initiator using carbon tetrachloride as inert solvent was investigated at 50°C. The polymerization follows ideal kinetics: the exponent values calculated for the initiator and monomer were found to be 0.5 and unity, respectively. A free radical mechanism with bimolecular termination was confirmed by the inhibiting effect of hydroquinone, a radical quencher. The rate of polymerization was a direct function of initiator (α-PCPY) concentraction, monomer (AN) concentration and temperature. The overall activation energy calculated was 56 kJ/mol. The polymerization was favoured by polar solvents and retarded by non-polar solvents.     

A new digital directional transverse differential currentprotection technique

Recently, several papers have discussed the protection of parallel transmission lines connected to common buses. The main purpose of this paper is to discuss problems associated with parallel line relaying schemes, which depend upon the theory of transverse differential protection relaying, and to present a new advanced technique to overcome these problems. The suggested technique relies on current incremental signals in corresponding phases instead of current magnitude. This method eliminates many of the associated problems typically encountered in this area. The possibility of applying the suggested technique on parallel three-terminal power transmission lines was investigated and satisfactory results were recorded. The voltage signal and the communication channel have been excluded from this study     

Heavy-ion fusion cross-section data for systems with compound atomic mass between 18 and 80

Fusion cross-section data are presented as a function of center-of-mass energy for different reactions involving light and medium-light heavy-ion systems with compound atomic mass number between 18 and 80. The systems range from ⁶Li + ¹²C to ⁴⁰Ca + ⁴⁰Ca. The data are given for the region starting from slightly below the Coulomb barrier energy to about six to seven times its value, if they are available. This compilation is primarily to facilitate theoretical interpretation of experimental results. It also serves to give researchers an overview of the range and status of the data. Literature published up to June 1983 has been surveyed.     

The prognostic value of the QT interval and QT interval dispersion in all-cause and cardiac mortality and morbidity in a population of Danish citizens

AIMS: To evaluate the prognostic value of the QT interval and QT interval dispersion in total and in cardiovascular mortality, as well as in cardiac morbidity, in a general population. METHODS AND RESULTS: The QT interval was measured in all leads from a standard 12-lead ECG in a random sample of 1658 women and 1797 men aged 30-60 years. QT interval dispersion was calculated from the maximal difference between QT intervals in any two leads. All cause mortality over 13 years, and cardiovascular mortality as well as cardiac morbidity over 11 years, were the main outcome parameters. Subjects with a prolonged QT interval (430 ms or more) or prolonged QT interval dispersion (80 ms or more) were at higher risk of cardiovascular death and cardiac morbidity than subjects whose QT interval was less than 360 ms, or whose QT interval dispersion was less than 30 ms. Cardiovascular death relative risk ratios, adjusted for age, gender, myocardial infarct, angina pectoris, diabetes mellitus, arterial hypertension, smoking habits, serum cholesterol level, and heart rate were 2.9 for the QT interval (95% confidence interval 1.1-7.8) and 4.4 for QT interval dispersion (95% confidence interval 1.0-19-1). Fatal and non-fatal cardiac morbidity relative risk ratios were similar, at 2.7 (95% confidence interval 1.4-5.5) for the QT interval and 2.2 (95% confidence interval 1.1-4.0) for QT interval dispersion. CONCLUSION: Prolongation of the QT interval and QT interval dispersion independently affected the prognosis of cardiovascular mortality and cardiac fatal and non-fatal morbidity in a general population over 11 years.     

Structural and magnetic investigations of some new boron containing rare earth intermetallic compounds

By alloying boron with RPd₃ (R=rare earth) compounds, new ternary alloys of the formula RPd₃B _x (0 ≤x ≤ 1) have been prepared. The parent RPd₃ compounds crystallise in the cubic AuCu₃ type structure. The addition of boron does not change the structure but results in an expansion of the lattice. Therefore, it is likely that the small boron atoms occupy the vacant body centred position in AuCu₃ type structure. It is also observed that compounds of the composition RRh₃B can be formed in the cubic structure for all rare earths R though the parent RRh₃ compounds exist only for R=Ce (AuCu₃ type) and La, Sm, Nd and Gd (all hexagonal CeNi₃ type). This points out the role of boron in stabilising new crystallographic phases. The results of susceptibility measurements on some of the RPd₃B and RRh₃B compounds are presented. In particular, it is noted that while GdPd₃ orders antiferromagnetically withT _N=6 K, GdPd₃B does not order magnetically down to 4.2 K.     

Acquired Glanzmann's thrombasthenia associated with Hodgkin's lymphoma: a case report and review of the literature

BACKGROUND: Acquired Glanzmann's thrombasthenia is a rare hemorrhagic diathesis resulting from impaired adhesive function of the platelet receptor GPIIb/IIIa (alpha(IIb)beta3). Typically, this disorder develops during adulthood, with patients manifesting fluctuating clinical and laboratory findings. To date, the underlying defect of most if not all cases of acquired Glanzmann's thrombasthenia results from an autoantibody or plasma protein inhibitor directed toward a demonstrably normal GPIIb/IIIa glycoprotein. METHODS: In this report, a patient with a history of treated Hodgkin's lymphoma presented with a severe hemorrhagic diathesis characterized by mild thrombocytopenia, a prolonged bleeding time, and defective platelet aggregation. RESULTS: Examination of the patient's platelet GPIIb/IIIa by Western blot analysis revealed no abnormality. Mixing studies demonstrated a non-immunoglobulin G plasma inhibitory factor, whereas flow cytometry analysis revealed elevated platelet-associated immunoglobulin (Ig) M. After an emergency colectomy for severe hemorrhage, the patient's qualitative and quantitative platelet parameters significantly improved. Pathology of the resected colonic segment demonstrated atypical lymphoid hyperplastic lesions. CONCLUSIONS: To the authors' knowledge, this is the first reported case of acquired Glanzmann's thrombasthenia associated with a putative IgM autoantibody. Furthermore, this report verifies the association of acquired thrombasthenia with lymphoproliferative disease. Although rare, awareness of this hemorrhagic diathesis as a possible sequelae of active or treated lymphoid disorders should encourage clinical vigilance of these patients.     

Cold stress, reverse T3 and lymphocyte function

Following a recently reported rise in serum reverse triiodothyronine levels in response to cold exposure, an initial in vitro study has been carried out on human lymphocyte function. The first part of the study demonstrated that the uptake of rT3 on lymphocyte nuclear receptors increased as the rT3 concentration was raised above the normal serum level. The binding is competitive with triiodothyronine. The lymphocytes were harvested from venous blood donated by young male U.S. naval personnel. The second part of the study involved lymphocyte proliferation assays carried out with the addition of increasing amounts of rT3. Both non-specific (three different mitogens) and specific (recall antigen) stimuli were used. There was an indication that lymphocyte function is depressed by increasing serum concentration of rT3. However, with a small number of test subjects and a resulting low statistical power, it was not possible to establish a statistically significant association. Lymphocytes from umbilical cord blood, which has a very high level of rT3 compared to that in normal adult sera, were also found to have a much reduced lymphocyte stimulation index. The requirements for a more definitive investigation are outlined.     

Investigation into the sintering of metals

Conclusions The authors studied the dependence of the strength of compounds obtained by sintering samples of technically pure iron on the duration, temperature and pressure.Sintering was carried out in a vacuum 1.33–0.13 KN/m² over a temperature range of 525–1060°C, a pressure range of 1.47–607.6 MN/m² and a duration of 3 min to 10 h.It is shown that a rise in pressure, temperature and duration of sintering raises the strength of the compound, which depends on the actual area of contact and the nondiffusive process, leading to the formation of bonds between the metal surfaces.To attain durable bonds it is necessary to have not only a close contact between the surface layers but also a nondiffusive local rearrangement of the crystal lattice on the contact surface. The activation energy of the displacement of atoms during rearrangement comprises 35.1 kJ/mole which is considerably less than the activation energy of the diffusion of iron.