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Background: Contact heat is commonly used in experimental research to evoke brain activity, most frequently acquired with electroencephalography (EEG). Although magnetoencephalography (MEG) improves spatial resolution, using some contact heat stimulators with MEG can present methodological challenges. This systematic review assesses studies that utilise contact heat in MEG, their findings and possible directions for further research. Methods: Eight electronic databases were searched for relevant studies, in addition to the selected papers' reference lists, citations and ConnectedPapers maps. Best practice recommendations for systematic reviews were followed. Papers met inclusion criteria if they used MEG to record brain activity in conjunction with contact heat, regardless of stimulator equipment or paradigm. Results: Of 646 search results, seven studies met the inclusion criteria. Studies demonstrated effective electromagnetic artefact removal from MEG data, the ability to elicit affective anticipation and differences in deep brain stimulation responders. We identify contact heat stimulus parameters that should be reported in publications to ensure comparisons between data outcomes are consistent. Conclusions: Contact heat is a viable alternative to laser or electrical stimulation in experimental research, and methods exist to successfully mitigate any electromagnetic noise generated by PATHWAY CHEPS equipment – though there is a dearth of literature exploring the post-stimulus time window.

Recent studies of interventional therapy by way of the coronary venous system have demonstrated that it can protect acutely ischemic myocardium. To evaluate the efficacy of coronary venous retroinfusion compared with systemic intravenous administration of recombinant tissue-type plasminogen activator (rt-PA), 14 dogs were studied with a copper coil-induced thrombus in the left anterior descending coronary artery. The rt-PA (24,000 fluorescence units/kg) was administered continuously, either intravenously (n = 8) or retrogradely (n = 6), for 30 min beginning 60 min after coronary occlusion. Thrombolysis was determined by repetitive coronary angiography. All dogs were killed 3 h after termination of rt-PA infusion and infarct size was measured by the triphenyltetrazolium chloride staining technique.Complete thrombolysis occurred in five of the six dogs in the retroinfusion group and four of the eight dogs in the systemic intravenous infusion group. Partial lysis was achieved in two dogs treated by intravenous infusion. Lysis did not occur in one dog treated with retroinfusion and in two dogs treated with intravenous infusion, Time to thrombolysis was 13.4 ± 2.3 min in the retroinfusion group versus 27.8 ± 4.8 min in the intravenous group (p < 0.001). Myocardial functional recovery in the ischemic zone measured by two-dimensional echocardiography 60 min after reperfusion was significant only in the retroinfusion group (p < 0.05). Infarct size expressed as a percent of the risk area (autoradiography) was significantly smaller in the retroinfusion group (34.9 ± 11.9%) than in the intravenous group (54.5 ± 19.1%; p < 0.05) despite < 15 min difference in average ischemic time between the groups (73.4 vs. 87.8 min). It is speculated that retroinfusion of rt-PA may prevent downstream embolization of microthrombi. No myocardial hemorrhages or damage to the coronary venous system were observed.It is concluded that coronary venous retroinfusion of rt-PA provides more rapid clot lysis and better functional recovery and infarct size reduction compared with systemic intravenous administration.

In the present study, the authors examined age effects in memory for nonverbal material. A picture fragment completion task was used to test explicit and implicit memory in a younger and an older group. Explicit memory was indexed by free recall of pictures, whereas implicit memory was indexed by perceptual learning (priming). Both free recall and perceptual learning performance were found to be impaired in the older group. A measure of executive functioning was found to be predictive of both explicit and implicit memory.

A prospective study of perioperative blood transfusion requirements for elective colorectal surgery over a 6-month period has been conducted. A total of 106 procedures was performed, 94 of which were for malignancy. A median of 2 units of packed red cells was cross-matched per patient. Twenty-three patients (21.7%) required a transfusion in the postoperative period. Fourteen of these patients required a second cross-match sample because their transfusion occurred more than 48 h after the original request. The greatest transfusion requirements were for patients undergoing abdominoperineal resection or subtotal colectomy. Routine perioperative cross-matching and reservation of blood for elective colorectal surgery may be an unnecessary expense, resulting in wastage of resources. A selective policy of serum being retained for grouping in these patients is justified.

The effects of the antiarrhythmic drugs lidocaine and bretylium tosylate on myocardial necrosis were studied in anesthetized pigs subjected to 60-min coronary occlusion followed by 3-h reperfusion. Group A (n = 7) received lidocaine (average dose +/- SD = 1,828 +/- 515 mg) before and during coronary occlusion and after reperfusion; the other series (group B, n = 7) received bretylium tosylate (3,457 +/- 1,323 mg). Infarct size was 16.3 +/- 14.7% in the lidocaine group as compared with 68.6 +/- 12.6% (p less than 0.01) in the bretylium group. In vitro release of superoxide anion from porcine granulocytes was studied using the lucigenin-dependent chemiluminescence technique. Lidocaine significantly reduced the peak chemiluminescence response to zymosan from 3.34 +/- 0.44 without lidocaine to 2.23 +/- 0.46 (p less than 0.01) and 1.06 +/- 0.17 mV (p less than 0.001), with lidocaine concentrations of 20 and 200 micrograms/ml, respectively. Bretylium had no effect on the chemiluminescence response. Adherence of porcine granulocytes to plastic was also reduced from 332 +/- 32 cells/mm2 (no lidocaine) to 247 +/- 35 and 206 +/- 26 cells/mm2 with lidocaine concentrations of 20 and 200 micrograms/ml, respectively (p less than 0.001). Bretylium had no significant effect. Eight additional bretylium-treated pigs received either rabbit antiporcine granulocyte serum (group C, n = 4) to reduce circulating granulocytes or nonimmune serum (group D, n = 4). Infract size in the granulocyte-depleted pigs was 26.6 +/- 5.6% as compared with 51.4 +/- 5.5% in pigs that received nonimmune serum (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

To determine the safety and efficacy of synchronized coronary venous retroperfusion during brief periods of ischemia, 30 patients undergoing angioplasty of the left anterior descending coronary artery were studied. Each patient underwent a minimum of two angioplasty balloon inflations. Alternate dilations were supported with retroperfusion; the unsupported inflations served as the control inflations. Synchronized retroperfusion was performed by pumping autologous femoral artery blood by means of an electrocardiogram-triggered retroperfusion pump into the great cardiac vein through a triple lumen 8.5F balloon-tipped retroperfusion catheter inserted percutaneously from the right internal jugular vein. Clinical symptoms, hemodynamics and two-dimensional echocardiographic wall motion abnormalities were analyzed. Retroperfusion was associated with a lower angina severity score (0.8 +/- 1 vs. 1.2 +/- 1) and delay in onset of angina (53 +/- 31 vs. 37 +/- 14 s; p less than 0.05) compared with the control inflations. The magnitude of ST segment change was 0.11 +/- 0.14 mV with retroperfusion and 0.16 +/- 0.17 mV without treatment (p less than 0.05). The severity of left ventricular wall motion abnormality was also significantly (p less than 0.01) reduced with retroperfusion compared with control (0.7 +/- 1.4 [hypokinesia] vs. -0.3 +/- 1.6 [dyskinesia]). There were no significant changes in hemodynamics, except in mean coronary venous pressure, which increased from 8 +/- 3 mm Hg at baseline to 13 +/- 6 mm Hg with retroperfusion. Four patients required prolonged retroperfusion for treatment of angioplasty-induced complications. The mean retroperfusion duration in these patients was 4 +/- 2 h (range 2 to 7). In the three patients who underwent emergency bypass surgery, the coronary sinus was directly visualized during surgery and found to be without significant injury. There were no major complications. Minor adverse effects were transient atrial fibrillation (n = 2), jugular venous catheter insertion site hematomas (n = 4) and atrial wall staining (n = 1), all of which subsided spontaneously. Thus, retroperfusion significantly reduced and delayed the onset of coronary angioplasty-induced myocardial ischemia and provided effective supportive therapy for failed and complicated angioplasty.

The efficacy of coronary venous versus left atrial administration of superoxide dismutase was studied in 24 open chest pigs which had 60 min of left anterior descending coronary artery occlusion followed by 3 h reperfusion. The pigs were randomly assigned to three treatment protocols: group A (n = 8) superoxide dismutase (5 mg kg-1) was infused into the great cardiac vein for 30 min beginning 15 min before reperfusion; group B (n = 8) superoxide dismutase (5 mg kg-1) was infused into the left atrium in a similar manner to group A; group C (n = 8) bovine serum albumin (5 mg kg-1) was infused into the great cardiac vein in the same manner as group A. Infarct size, expressed as percent of area at risk, was significantly smaller in group A (28.2 +/- 13.0%) than groups B (58.7 +/- 8.3%) and C (61.6 +/- 7.2%) (P less than 0.05). The results indicate that retroinfusion of superoxide dismutase into the great cardiac vein before reperfusion may be an effective treatment for the prevention of reperfusion injury, even in the absence of a well developed coronary collateral circulation. Antegrade (left atrial) administration of the same amount of superoxide dismutase did not decrease infarct size in pigs. The most likely explanation for this difference in efficacy is that drug delivery with left atrial administration is dependent on antegrade flow with reperfusion which is less reliable and less efficient than coronary venous retroinfusion. The latter provides a predictably high concentration of superoxide dismutase to the jeopardized myocardium during the period of ischaemia before reperfusion.

We studied 32 transverse left ventricular slices of myocardium from 16 pigs after 45 to 100 minutes of coronary artery occlusion followed by 180 minutes of reperfusion. Infarct area for each slice was determined as follows: (1) grossly, by triphenyl tetrazolium chloride staining of each slice, and (2) microscopically, by complete histologic sectioning of the triphenyl tetrazolium chloride-stained surface of each slice. Planimetry of necrotic and nonnecrotic areas was performed from tracings and photographs of triphenyl tetrazolium chloride-stained slices and from actual histologic sections. When triphenyl tetrazolium chloride and histologic measurements were compared, necrotic tissue area had decreased 11.4% +/- 15.0% (2.59 +/- 1.04 vs 2.09 +/- 0.86 cm2). Nonnecrotic tissue area decreased 20.6% +/- 24.0% (8.31 +/- 3.79 vs 5.16 +/- 2.73 cm2). In this model of ischemia followed by reperfusion, with fixation and processing, viable tissue shrank almost twice as much as necrotic tissue. This differential shrinkage introduces an error resulting in overestimation of infarct size by histologic quantitation.

Clinical trials to determine the safety and efficacy of diastolic coronary venous retroperfusion have recently been initiated, more than 10 years after successful introduction of the technique in the animal laboratory. To date, diastolic retroperfusion has been employed in two clinical situations: in patients undergoing percutaneous transluminal coronary angioplasty, and in patients with medically refractory unstable angina. The number of patients who have been studied is relatively small. Nevertheless, the preliminary results have been encouraging and suggest that diastolic retroperfusion may provide an effective alternate blood supply for temporary support of patients with acute myocardial ischemia.

Pt/Sn electrodeposited catalysts have been prepared, characterized and tested for the electro-oxidation of methanol. Catalyst activities were measured in 3 M H2SO4 electrolyte between ambient temperature and 95°C. Enhancement in specific activity by a factor of about 50 was found over electrodeposited platinum black. This behaviour is in contrast to that of alloys of platinum and tin which were found to have very low activities compared with platinum catalysts and to be readily corroded in H2SO4 electrolyte. ESCA (electron spectroscopy for chemical analysis) studies and Mossbauer spectroscopy showed the majority of the tin in the deposit to be present in an oxidized form. A small amount (∼17%) was present as a dilute alloy of tin in platinum. Surface area measurements and X-ray powder diffraction indicated that the increase in activity over platinum black was not attributable to smaller platinum particle size. It seems that the combination of platinum and tin results in a decrease in the poisoning effect by strongly adsorbed organic residues. Whether this arises from the operation of a cyclic Sn(II)/Sn(IV) redox system or from modification of the platinum surface remains unresolved.

Phosphoric acid and sulphuric acid have been compared as potential electrolytes for methanol-air fuel cells. The performances of typical electro-oxidation catalysts were measured in both electrolytes over a range of concentrations. With all catalysts the activity falls with increasing acid concentration. While this is to some extent due to the decrease in water activity at higher concentrations it seems that with both acids there is significant poisoning of the catalyst. The results can be explained for both electrolytes by assuming that adsorption of undissociated acid poisons the catalyst surfaces and that the reaction rate on the poisoned surfaces is proportional to the water activity.

SUMMARY Rates of ethephon with mepiquat chloride (as ‘Terpal’) were foliar applied to winter barley during early flag leaf emergence with or without soyal lecithin acidified with proprionic acid included as an adjuvant (‘LI700’). In both the glasshouse and field increasing the rate of ‘Terpal’ decreased the rate of stem extension exponentially, which in turn led to progressively shorter stands. As crop height extended above 0.9 m both the proportion of crop area lodged and the severity of lodging (mean angle of culms to the vertical) increased. As lodging progressed, mean grain weight was depressed and therefore ethephon with mepiquat chloride had the potential to increase yield. However, in the absence of lodging, applications of ‘Terpal’ reduced yield in direct proportion to increasing the dose rate. The influence of ‘Terpal’ on yield becomes a complex interaction between phytotoxicity, probably resulting from exogenous ethylene applications and benefits accruing from the control of lodging. Adding ‘LI700’ as an adjuvant enhanced the performance of ‘Terpal’ in reducing both rate of stem extension and mean grain weight in the absence of lodging.

The effects of synchronized coronary venous retroperfusion of arterial blood on myocardial washout were studied with digital subtraction angiography in 10 closed chest dogs during balloon occlusion of the proximal left anterior descending coronary artery. The center lumen of the intracoronary balloon catheter was used for sequential injections of 1 ml (meglumine diatrizoate) Renografin-76, and contrast washout rate was determined by videodensitometry in myocardial regions subserved by the left anterior descending coronary artery. Before coronary artery occlusion, washout rate was 22.4 +/- 2.7 min-1 (mean +/- SEM). Five minutes after occlusion, and immediately before synchronized retroperfusion, washout rate dropped sharply to 2.0 +/- 0.7 min-1. Twenty-five minutes after occlusion, with 50 ml/min synchronized retroperfusion treatment applied for 5 minutes, washout rate was 5.0 +/- 1.5 min-1. Thus, synchronized retroperfusion significantly (p less than 0.05) accelerated contrast disappearance over that during presynchronized retroperfusion ischemia. To determine the effects of synchronized retroperfusion on retrograde delivery to the ischemic myocardium, monastral blue dye was retroinfused through the system into the great cardiac vein before the dog was killed. Transverse heart slices were then studied by light microscopy, and regional intravascular dye content was scored from 0 to 3 (0 = no dye, 3 = maximal dye). After great cardiac vein synchronized retroperfusion, blue dye content in capillaries of ischemic anterior and nonischemic posterior aspects of the left ventricle was 2.3 +/- 0.5 versus 0.7 +/- 0.3, respectively (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Isotope separation factors of seventeen two‐phase equilibrium systems for lithium isotope enrichment have been determined. In all cases, lithium amalgam was used as one of the lithium‐containing phases and was equilibrated with an aqueous or organic phase containing a lithium compound. In all systems examined, isotopic exchange was found to be extremely rapid, and 6Li was concentrated in the amalgam phase. The isotopic separation factor for the LiOH(aqueous) vs Li(amalgam) system has been studied as a function of temperature from −2 to 80 °C. The values obtained have been compared with the ’’electrolysis’’ and exchange separation factors given in the literature. The two‐phase systems, LiCl(ethylenediamine) vs Li(amalgam) and LiCl(propylenediamine) vs Li(amalgam), have been studied, and the isotopic separation factors have been determined as functions of the temperature. The factors for the two systems have been found to be substantially the same (within limits of the errors involved) over the temperature range studied (0 to 100 °C) as those for the aqueous system. The isotopic separation factors for the seventeen systems have been tabulated, and correlations have been drawn that show the salt and solvent effects upon the values obtained.

The Laplace transform of the ring current transient is easier to interpret theoretically than the transient itself. A simple unit for carrying out the transformation is described. Results from the application of the technique are in good agreement with theory.

Boron trifluoride adds to many Lewis bases to form 1:1 molecular addition compounds. Under favorable conditions, some of these adducts may be used to fractionate the isotopes of boron by means of the following reaction: Donor·11BF3(l)+10BF3(g)=Donor·10BF3(l)+11BF3(g). The equilibrium constants for this reaction vary with donor, donor substituents, and temperature. At 30°C the following order is observed: (C2H5)2S> (CH3)2S>(CH3)2Se>(C4H9)2S>(C2H5)2O>C6H5OCH3>(CH3)2O≥(CH2)4O>C6H5OH>(C2H5)3N. The ``anomalous'' concentration of boron‐10 in the molecular addition compound may be explained by the unique chemistry of the boron and fluorine atoms. A model is proposed which accounts for observed variations in the isotopic fractionation factor when different donors are used, as well as when different substituents are present on a selected donor. The model also explains the isotopic behavior of other boron halides.

Theory is presented for alternating current measurements at a ring-disc electrode; the theory describes the phase shift and amplitude of the alternating ring current with respect to the alternating disc current. Experimental results are in reasonable agreement with the theory.

BS>A small automatic isotope separation cascade was constructed and operated to evaluate the use of the HNO/sub 3/-NO chemical exchange reaction as a method of separating nitrogen-15 on a large-scale basis. Successful operation of the cascade over a long period of time demonstrated the technical feasibility of the chemical process and the cascade design. The most sensitive technical scale- up problem was found to be the desiga of the nitric acid refluxers. The most important economic factor was the favorable disposition of large quantities of by- product sulfuric acid. (auth)

Studies were made of the nitrogen‐isotope effects occurring during the alkaline reduction of NO3−, NO2−, and NH2OH with Fe(II). The pertinent reduction reactions were shown to be irreversible and the yields of NH3 quantitative. The reduction of NO3− to NH3 produced a k14/k15 value of 1.075±0.004 at 25°C. A k14/k15 ratio of 1.034±0.002 at 25°C was obtained for the reduction of NO2−, or NH2OH to NH3. The rate constant, kNO3−, was shown to be slow compared to kNO2− and kNH2OH which had values of 4.09×10−2 and 9.53×10−3 sec−1, respectively.The experimental data agreed well with results computed for a two‐atom model in which the significant step in the reduction of each species was the breaking of an N–O bond. Reactions consistent with the experimental data were proposed to account for the reduction mechanism.

The nitrogen isotope effects produced upon fractionally decomposing C6H5NNCl, C6H5NNBF4, m‐ClC6H4NNBF4, o‐, m‐, and p‐CH3C6H4NNBF4 were measured as a function of temperature. Between 5° and 70°C the data are well represented by the least‐squares equation, log(k14/k15)=6.949/T−0.002528. The experimental results agree well with those predicted from spectroscopic data. The data are consistent with the model in which decomposition occurs through the rupture of a single C–N bond. The observed isotope effect is insensitive to the nature and position of substituents on the aromatic ring and to the anion of the salt. The difference in the activation energy for the decomposition of the 14N‐ and 15N‐labeled diazonium salts is 32 cal mole−1·deg−1.

The BF3 complexes of ethyl ether, ethyl sulfide, and triethylamine were studied. Isotopic equilibrium constants for the reactions B10F3(g)+B11F3·donor(l)⇌B10F3(g)+B10F3·donor(l) were measured at several temperatures for each of the three systems. Vapor pressures of the ethyl sulfide complex, and rates of exchange of boron between BF3 and BF3·Et3N were also determined.

A simple analytical expression using three parameters is presented which describes the variation of Nκ with x for a ring-disc electrode to an accuracy of about 2 % in the range x > 1. Values of the three parameters are tabulated for electrodes of common radius ratios. The parameters can also be used to describe transient behaviour at the ring-disc electrode.