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The objective of this study was to evaluate the effect of timing of electrical stimulation on free calcium concentration, calpain-2 activity, Warner-Bratzler shear force (WBSF), and consumer sensory analysis. Twenty-three beef steers were harvested and stimulated (S) using extra-low voltage or not stimulated (NS), at exsanguination and/or 1 h postmortem, resulting in 4 different stimulation treatments: NS-NS, NS-S, S-NS, or S-S. Samples were removed from the longissimus lumborum (LL) and semimembranosus (SM) for free calcium and calpain-2 analysis on days 1, 4, and 14 postmortem. WBSF and sensory analysis steaks were removed on day 4 and frozen (4 d) or aged to 14 d postmortem. Data were analyzed using the mixed model or generalized linear mixed model procedure of SAS (SAS Institute, Inc., Cary, NC), with significance determined at P < 0.05. There was a tendency for an aging-period-by-stimulation-treatment interaction for LL free calcium concentration (P = 0.05), and there was a significant difference between aging periods (P < 0.01). No difference was observed in free calcium concentration in the SM between stimulation treatments (P = 0.44); aging, however, significantly increased SM free calcium concentration (P < 0.01). Stimulation did not impact native calpain-2 activity in the LL (P = 0.71) or SM (P = 0.89). Stimulation treatment did not improve tenderness values for WBSF analysis for the LL (P = 0.69) or SM (P = 0.61) or consumer sensory analysis in the LL (P = 0.56) or SM (P = 0.36). A longer aging period tended to increase calpain-2 activity in the SM (P = 0.08), improve WBSF in the LL (P = 0.09), and significantly improve consumer tenderness scores in the SM (P < 0.01). In conclusion, the timing of electrical stimulation utilized in the current study tended to influence free calcium concentration in the LL but did not influence calpain-2 activity or beef tenderness. Aging, however, improved tenderness.

Neuronal stimulation of most isolated precontracted gastrointestinal smooth muscle results in relaxation. This study examined the changes in cyclic nucleotide content associated with neuronally induced relaxation in sphincteric and nonsphincteric smooth muscle of the gut. Electrical field stimulation produced a frequency-dependent relaxation of the guinea pig proximal colon (EF50= 1.6 Hz) and taenia coli (EF50= 2.4 HZ), and the canine proximal colon (EF50= 3.1 Hz) and internal anal sphincter (EF50= 3.0 Hz). Changes in cyclic nucleotide content occurred during EFS-induced relaxation. Cyclic AMP levels were significantly increased in the guinea pig poximal colon and taenia coli and in the canine proximal colon. No change in cyclic GMP occurred in these smooth muscles. Conversely, in the canine internal anal sphincter the cyclic GMP content increased significantly with no change in cyclic AMP. These effects in this sphincter are similar to those identified previously in the lower esophageal sphincter of opossum, dog, and man. Tetrodotoxin blocked the EFS-induced relaxation and the associated accumulation of cyclic nucleotides of all tissues. Therefore, EFS-induced relaxation is mediated by the activation of neurons and the release of inhibitory neurotransmitter(s). Also, EFS-induced relaxation is closely associated with increases in smooth muscle cyclic nucleotide content. Most importantly, the change in cyclic nucleotide accumulation that occurs during EFS-induced relaxation is different for sphincteric and nonsphincteric smooth muscle, (i.e., different cyclic nucleotides are generated in sphincteric and nonsphincteric smooth muscle in response to stimulation of nonadrenergic, nonchohnergic, inhibitory enteric neurons).

Nanostructures of self-assembled monolayers (SAMs) are designed and produced using coadsorption and nanografting techniques. Because the structures of these artificially engineered domains are predesigned and well-characterized, a systematic investigation is possible to study the mechanical responses to force modulation under atomic force microscope tips. Force modulation imaging reveals characteristic contrast sensitivity to changes in molecular-level packing, molecule chain lengths, domain boundaries, and surface chemical functionalities in SAMs. By means of actively tuning the driving frequency, the resonances at the tip-surface contact are selectively activated. Therefore, specific surface features, such as the edges of the domains and nanostructures or desired chemical functionalities, can be selectively enhanced in the amplitude images. These observations provide a new and active approach in materials characterization and the study of nanotribology using atomic force microscopy.

Feeding behavior has the potential to enhance prediction of feed intake and to improve understanding of the relationships between behavior, DMI, ADG, and residual feed intake (RFI) in beef cattle. Two cohorts, born in 2009 and 2010, the progeny of Red Angus bulls (n = 58 heifers and n = 53 steers), were evaluated during the growing phase, and the latter group of steers was also evaluated during the finishing phase. All behavior analyses were based on 7 feeding behavior traits (bunk visit frequency, bunk visit duration [BVDUR], feed bout frequency, feed bout duration, meal frequency, meal duration, and average meal intake) and their relationships with ADG, DMI, and RFI. During the growing phase, feeding duration traits were most indicative of DMI with positive correlations between BVDUR and DMI for cohort 1 steers, growing phase (n = 28, r = 0.52, P = 0.00); cohort 2 steers, growing phase (n = 25, r = 0.44, P = 0.01); and cohort 2 heifers, growing phase (n = 29, r = 0.28 P = 0.05). There were similar trends toward correlation of BVDUR and RFI for both steer groups and cohort 1 heifers, growing phase (C1HG; n = 29; r = 0.27, P = 0.06; r = 0.30, P = 0.07; and r = 0.26, P = 0.08, respectively). Feed bout frequency was correlated with ADG in C1HG and in cohort 2 steers, finishing phase (r = -0.31, P = 0.04, and r = 0.43, P = 0.01, respectively). Feed bout duration was correlated with ADG in heifer groups (r = 0.29 and r = 0.28, P = 0.05 for both groups) and DMI for all growing phase animals (r = 0.29 to 0.55, P ≤ 0.05 for all groups). Evaluation of growing vs. finishing phase steer groups suggests that all behaviors, RFI, and DMI, but not ADG, are correlated through the growing and finishing phases (P ≤ 0.01 for all variables excluding ADG), implying that feeding behaviors determined during the growing phase are strong predictors of DMI in either life stage. Sire maintenance energy EPD effects (measured as high or low groups) on progeny feeding behaviors revealed a difference in meal duration with a tendency to differ in average meal intake (P = 0.01 and P = 0.07, respectively). Feeding behavior duration traits may be useful predictors of DMI in Red Angus cattle.

New approaches to limit expenses associated with input, without compromising profit, are needed in the beef industry. Residual feed intake (RFI) is an efficiency trait that measures variation in feed intake beyond maintenance, growth, and body composition. The addition of feeding behavior analysis to standard RFI tests may provide an approach to more readily identify feed-efficient cattle. The current study analyzes 7 feeding behaviors (BVFREQ: bunk visit frequency, BVDUR: bunk visit duration, FBFREQ: feed bout frequency, FBDUR: feed bout duration, MFREQ: meal frequency, MDUR: meal duration, and AMINT: average meal intake) and their relationships with RFI, ADG, and DMI in Japanese Black (Wagyu) cattle. Three cohorts of yearling Wagyu animals were studied using a standard 70-d RFI test, and data from divergent ( ± 0.5 SD from population RFI mean) subsets of animals were analyzed for feeding behaviors [n = 58, bulls on high-concentrate diet (C1); n = 36, bulls on a lower-concentrate diet (C2); n = 34, heifers on a lower-concentrate diet (C3)]. The following behaviors were correlated with ADG: BVFREQ (r = 0.32, P = 0.01; C1 bulls), BVDUR (r = 0.42, P = 0.01, C2 bulls), FBFREQ (r = 0.37, P0.01; C1 bulls), FBDUR (r = 0.46, P0.01, C1 bulls), and MFREQ (r = 0.42, P0.01, C2 bulls). Behaviors were trending or significantly correlated with DMI for all cases except for MFREQ for C3 and AMINT for C2. Residual feed intake was positively correlated with MDUR across all cohorts (r = 0.31, P = 0.02; r = 0.38, P = 0.02; r = 0.54, P ≥ 0.01, respectively). For C2 bulls and C3 heifers, RFI was positively correlated with behavior frequency categories (BVFREQ; r = 0.44, P = 0.01; r = 0.60, P ≤ 0.01, respectively, and FBFREQ r = 0.46, P ≤ 0.01; r = 0.60, P ≤ 0.01, respectively). Bunk visit frequency and FBFREQ were highly correlated with RFI status (high or low) in C2 bulls and C3 heifers. Behavior duration categories (BVDUR, FBDUR, and MDUR) were most correlated with efficiency status in C1 bulls. However, behavior frequency categories (BVFREQ and FBFREQ), as well as MDUR, were most correlated with efficiency status in C2 bulls and C3 heifers. Inclusion of meal duration measurements when evaluating RFI provides an additional tool in understanding the drivers of variation in this important trait in Wagyu cattle. The present study provides new insights into feed intake patterns of a beef breed for which there are few reports of feeding behavior.

Investigating the genetic and physiological drivers of postweaning residual feed intake (RFI) and finishing phase feed efficiency (FE) may identify underlying mechanisms that are responsible for the variation in these complex FE traits. The objectives were 1) to evaluate the relationship of serum IGF-I concentration and muscle gene expression with postweaning RFI and sire maintenance energy (MEM) EPD and 2) to determine fiber type composition as it relates to postweaning RFI and finishing phase FE. Results indicate that RFI and serum IGF-I concentration were not associated (P0.05); however, negative correlations (P0.05) between sire MEM EPD and serum IGF-I concentration were observed. Gene expression differences between high- and low-RFI animals were observed in cohort 1, where IGFBP5 expression was greater (P0.05) in high-RFI animals. When animals were grouped according to sire MEM EPD, the low MEM EPD group of cohort 1 showed greater muscle mRNA expression (P0.01) of fatty acid synthase (FASN) and marginally (P0.10) greater expression of IGFBP5 and C/EBP alpha (C/EBPα) whereas the high MEM EPD group of cohort 2 had greater muscle mRNA expression of IGFBP2 (P0.05) and C/EBPα (P ≤ 0.01) and marginally (P0.10) greater expression of IGFBP3. Biopsy tissue samples collected at harvest revealed that the percentage of type IIa fibers was lower (P ≤ 0.05) in high-RFI steers, with a similar trend (P0.10) being observed in high finishing phase FE steers. The percentage of type IIb fibers was higher (P0.05) in high-RFI (and finishing phase FE) steers than in low-RFI (and finishing phase FE) steers. There was a marginal, negative correlation between RFI and type I (r = -0.36, P = 0.08) and IIa (r = -0.37, P = 0.07) fiber percentages and a positive correlation (r = 0.48, P = 0.01) between RFI and type IIb fiber percentage whereas finishing phase FE was negatively correlated (r = -0.43, P = 0.03) with type I fiber percentage and positively correlated (r = 0.44, P = 0.03) with type IIb fiber percentage. Therefore, our data indicate that 1) serum IGF-I (collected at weaning) is not an indicator of postweaning RFI, 2) the GH-IGF axis appears to have some involvement with RFI at the molecular level; however, muscle gene expression results were not consistent across cohorts, and 3) low-RFI animals may have the ability to more efficiently maintain and accrete muscle mass due to their fiber type composition, specifically a greater proportion of type I fibers.

Energy expenditure is a physiological process that may be closely associated with residual feed intake (RFI). The maintenance energy (ME(M)) EPD was developed by the Red Angus Association of America (RAAA) and is used as an indicator of energy expenditure. The objectives of this study were to evaluate and quantify the following relationships using progeny of Red Angus (RA) sires divergent for ME(M) EPD: 1) postweaning RFI and finishing phase feed efficiency (FE), 2) postweaning RFI and end-product quality, and 3) postweaning RFI and sire ME(M) EPD. A total of 12 RA sires divergent for ME(M) EPD were chosen using the RAAA-generated ME(M) EPD values and were partitioned into 2 groups: high ME(M) EPD (≥4 Mcal/mo) and low ME(M) EPD (4 Mcal/mo), based on the breed average of 4 Mcal/mo. Commercial crossbred cows were inseminated to produce 3 cohorts of progeny, which were tested for postweaning RFI (cohorts 1, 2, and 3) and finishing phase FE (cohorts 1 and 3). Results indicate that postweaning RFI and finishing phase FE of steer progeny tended to be positively correlated (r = 0.38; P = 0.06) in cohort 1 and were positively correlated (r = 0.50; P = 0.001) in cohort 3. In addition, postweaning RFI was not phenotypically correlated (P0.05) with any carcass traits or end-product quality measurements. Sire ME(M) EPD was phenotypically correlated (P0.05) with carcass traits in cohort 1 (HCW, LM area, KPH, fat thickness, and yield grade) and cohort 2 (KPH and fat thickness). Since variation in measured LM area was not explained by the genetic potential of rib eye area EPD, and therefore, the observed correlation between sire ME(M) EPD and measured LM area may suggest an association between ME(M) EPD and LM area. A correlation (r = 0.24; P = 0.02) was observed between postweaning RFI and ultrasound intramuscular fat percentage in cohort 2 but was not detected in cohorts 1 or 3. In addition, no phenotypic relationship was observed (P0.05) between progeny postweaning RFI and sire ME(M) EPD. Therefore, results suggest 1) RFI measured during the postweaning growth phase is indicative of FE status in the finishing phase, 2) neither RFI nor sire ME(M) EPD negatively affected carcass or end-product quality, and 3) RFI and sire ME(M) EPD are not phenotypically associated.

Increases in cyclic adenosine monophosphate and cyclic guanosine monophosphate content accompany relaxation of isolated strips of opossum and canine lower oesophageal sphincter muscle. The aim of this investigation was to characterise these responses in isolated muscle from the human lower oesophageal sphincter. Electrical stimulation of enteric neurons produced a frequency dependent relaxation of the human lower oesophageal sphincter that was sensitive to tetrodotoxin. Furthermore, as previously shown in the opossum and canine lower oesophageal sphincter, cyclic guanosine monophosphate content was significantly raised in muscle strips frozen during maximum electrical field stimulation whereas cyclic adenosine monophosphate content was unchanged. In addition, sodium nitroprusside (EC50 = 0.1 microM) produced a concentration dependent relaxation of human lower oesophageal sphincter, significantly increased cyclic guanosine monophosphate content, but did not alter cyclic adenosine monophosphate content. Zaprinast (M&B 22948) and SK&F 94120, selective inhibitors of cyclic guanosine monophosphate and cyclic adenosine monophosphate phosphodiesterases, respectively, both relaxed human lower oesophageal sphincter with a potency similar to that seen in the dog or opossum lower oesophageal sphincter. Finally, the 8-bromo analogues of both cyclic adenosine monophosphate (EC50 = 420 microM) and cyclic guanosine monophosphate (EC50 = 100 microM) relaxed the human lower oesophageal sphincter. These studies suggest that in the human, as well as the canine and opossum lower oesophageal sphincter, increases in cyclic nucleotide content are associated with relaxation and increases in cyclic guanosine monophosphate are associated with the relaxation induced by stimulation of enteric neurons.

Increased fecal pellet output that occurs during cold-restraint stress (CRS) was evaluated systematically. Free-feeding rats, which exhibit a reduced occurrence of gastric ulcers under these conditions, were studied. CRS significantly increased fecal pellet production and fluid content. However, the fecal output produced during CRS was not associated with increased gut secretory activity or somatic motor activity associated with cold restraint and did not occur in anesthetized animals. Cold and restraint stress were additive in producing increased fecal output. Significant dose-related decreases in fecal output were produced by drugs that decrease gut transit (i.e., B-HT 920, clonidine, Lomotil, loperamide, and lidamidine). Anticholinergic-antisecretory drugs, antidepressants, and tranquilizers had little effect on fecal output or fluid content. Changes in gastrointestinal transit did not contribute to the increased fecal output during CRS. Transit in the lower small intestine was not altered, but the cecum tended to empty more contents into the large intestine during CRS. Colonic transit was dramatically affected by CRS, which eliminated retrograde transit and produced the evacuation of the majority of colonic contents. The increased colonic transit produced by CRS was decreased in a dose-related fashion by hexamethonium, nifedipine, loperamide, and B-HT 920. In several time-response and drug-inhibition studies during CRS, both fecal pellet output and colonic transit were affected similarly. These data indicate that CRS appears to change central nervous system output to the colon and that it alters colonic smooth muscle motility in a manner that facilitates colonic transit and evacuation. Small intestinal transit is not involved in this phenomenon and is regulated differently during CRS.

Cyclic nucleotides mediate relaxation of gastrointestinal smooth muscle. The intracellular concentration of these second messengers is determined by a balance between their synthesis and metabolism. Because cyclic nucleotide phosphodiesterase enzymes (PDE) are the sole enzymes responsible for their degradation, it is essential to determine the role of the various PDE isozymes in regulating cyclic nucleotide content of gastrointestinal smooth muscle. To examine the role of different PDE isozymes in colonic smooth muscle motility, soluble PDE activity was measured in fractions obtained from homogenates of canine colon using DEAE sepharose chromatography. PDE activity was determined using [3H]cyclic AMP (cAMP) (1 microM) or [3H]cyclic GMP (cGMP) (1 microM) as a substrate. Results indicated that colonic smooth muscle contains at least two forms of PDE with a high affinity for cGMP. One form was stimulated by calmodulin (type I) and the other was inhibited by low concentrations of zaprinast (type V). In addition, colonic smooth muscle contains at least two isozymes that prefer cAMP as a substrate. One form was inhibited by SB 94120 and cGMP (type III) and the other by rolipram (type IV). An additional peak of PDE activity was identified. The hydrolysis of cAMP by this peak was greatly enhanced by the presence of cGMP, suggesting that this activity belonged to type II or cGMP-stimulated PDE. The functional role of these isozymes was evaluated by determining the ability of selective PDE inhibitors to antagonize a carbachol (0.3 microM)-induced contraction of isolated circular colonic muscle strips in the presence of forskolin (0.2 microM). Concentration-dependent decreases in contractile activity were observed with the following potency order: rolipramRo 20-1724isobutyl methylxanthineSB 94120zaprinast. These results demonstrate that colonic smooth muscle contains several PDE isozymes and that selective inhibition of PDE isozymes can increase cyclic nucleotide content and antagonize contractile responses. Functionally, PDE IV appears to be very important in reducing contractile activity, suggesting that selective PDE IV inhibitors might be useful in the treatment of gut hypermotility disorders.

Addition of 5-HT or SKF 103829 (2,3,4,5 tetrahydro-8[methyl-sulfonyl]-1 H-3-benzazepin-7-ol hydrobromide) contracts isolated strips of canine lower esophageal sphincter (LES) circular smooth muscle. 5-HT acts directly on the smooth muscle, since pretreatment with the neurotoxin TTX does not inhibit this contraction. Depletion of extracellular calcium or pretreatment with nifedipine inhibited the contraction to both 5-HT and SKF 103829. Therefore, in this smooth muscle, the contraction produced by both 5-HT and SKF 103829 requires extracellular calcium and is sensitive to inhibition by a voltage-dependent Ca2+ channel antagonist. In addition, with respect to 5-HT, SKF 103829 appeared to act as a partial agonist. Receptor alkylation studies using phenoxybenzamine demonstrated no receptor reserve for the contractile response to 5-HT. Nonsurmountable antagonism of the contraction induced by 5-HT and SKF 103289 was observed with several 5-HT2 antagonists, i.e., methysergide, ketanserin, cyproheptadine, and LY 53857. Using a method established for pseudoirreversible antagonism, the Ki values for these 5-HT2 receptor antagonists were estimated. Results suggested that both 5-HT and SKF 103829 contract the canine LES by interacting at the same receptor site and that this receptor site has characteristics of the 5-HT2 receptor. Finally, neither bulbocapnine, domperidone, nor prazosin significantly alters the response to 5-HT or SKF 103829. Thus, isolated strips of canine LES contain a contractile 5-HT2 receptor, and SKF 103829 behaves as a partial agonist at this site.

For airline pilots, sleep deprivation and circadian desynchronization due to rapidly rotating shift schedules, rapid time zone changes, and unorganized sleep/wake cycles can result in severe performance decrements. Twelve case histories of accidents in which pilot scheduling might have been a factor are reviewed, and suggestions for the chronohygiene of pilot scheduling are made.

Alloys are dissolved in nitric acid followed by hydrofluoric acid. Borax is added to complex the excess of fluoride and to act as spectroscopie buffer. Results obtained for up to 12 elements in 7 standard alloys are accurate.

A 4-day tumour sensitivity assay of potential use in predicting tumour response to cytotoxic drugs has been investigated in patients with chronic lymphocytic leukaemia. The method comprised isolation of white cells from peripheral blood, drug exposure and incubation for 4 days. Drug-induced tumour cell kill was assessed by differential staining of dead and live cells such that the latter could be morphologically identified, with subsequent calculation of tumour cell viability. Concentrations of drug for use in the assay were chosen for chlorambucil (2 micrograms ml-1), 4-hydroperoxy-cyclophosphamide (2 micrograms ml-1)--which was used in vitro in place of cyclophosphamide--prednisolone (0.5 microgram ml-1) and vincristine (0.1 microgram ml-1), to give a scatter of values which was in good agreement with clinical expectations. In 21 cases where the in vitro result could be compared with the in vivo response, there were 4 true positive comparisons (sensitive in vitro, sensitive in vivo), 15 true negative comparisons (resistant both in vitro and in vivo) and 2 false positive comparisons (sensitive in vitro, resistant in vivo). A result was obtained in 86% (65/76) of samples received. The assay appears to show considerable promise as a tumour chemosensitivity test and warrants wider investigation, including prospective in vivo/in vitro correlations that could be based on the results presented here. Images Figure 1

Because of difficulties in quantitatively transferring accurately weighed solid microsamples into electrothermal atomizer tubes, various materials were investigated for their suitability as cups or carriers. Plastics, ‘ashless’ papers and cellulose acetates, though theoretically completely destructible at the ashing step, were found to have two principal disadvantages: they contribute comparatively high and variable blank values of many common elements; the residues left in the tube after atomization of solid metal and refractory samples lead to inaccuracy of reading and to much shortened tube life. Graphite cups not only overcome these problems but have the positive advantage that their use results in a usefully higher sensitivity for the elements investigated. Some brief examples of the use of graphite cups are quoted, but it is emphasized that the method of calibration must still be carefully checked. The reasons for the improved sensitivity of the graphite cup method and its relationship to the L'vov ‘platform’ method are discussed.

The depression of chromium absorption by iron has been investigated. Experimental results are presented which suggest that the interference may be explained in terms of the physical properties of metallic iron and the size of the particles produced in the flame. No evidence for the formation of a mixed oxide phase, such as chromite, has been found.

Several acoustic properties of anisotropic media have been investigated by the pulsed ultrasonic method and the results analyzed in terms of plane waves traveling through an infinite medium. Single crystals of ammonium dihydrogen phosphate (ADP) and potassium dihydrogen phosphate (KDP) were the subjects of this study and in each case velocity measurements were used to compute a complete set of elastic moduli. Coupling between modes which results in the simultaneous generation of two modes by a transducer and in the transfer of energy between modes during a reflection was studied. The phenomenon of acoustical birefringence in ADP was particularly investigated and it was found that all of the three modes with wave normals in the 45° direction in the yz plane are propagated in different directions making non‐zero angles with the wave normals. A case in which the anisotropic property of the medium causes anomalous beam spreading is reported and the circumstances leading to this condition are discussed.

Citrate ions have been found to interfere seriously in the determination of iron by atomic-absorption spectrometry with an air-acetylene flame. Addition of phosphoric acid or sodium chloride overcomes the interference. Mechanisms are proposed to account for these effects. It is concluded that the state of subdivision of the iron species in the flame plays an allimportant role in determining the pattern of interference.

This instrument for evaluation in photographic spectroscopy is a projection-comparator provided with means for displaying a density profile of part of the spectrum. The design allows the projected spectrum images to remain stationary for examination while the density profile is displayed simultaneously on a cathode-ray tube. Applications to both qualitative and quantitative spectrography are outlined.

Atomic absorption spectrophotometry has been used to compare the concentrations of iron and tin in canned fruit juice with those in juice not stored in cans. No significant difference was found in the level of iron, but the amount of tin was considerably higher in canned samples. The determination is rapid, and no ashing procedure is required.

A method has been developed for the determination, by atomic absorption spectrophotometry, of calcium, magnesium, sodium, potassium, manganese and zinc in fruit juices. The metals may be determined by direct aspiration of the sample, suitably diluted with water, after removal of suspended matter by centrifugation. It is not necessary to ash the samples prior to analysis. Results are given for the analysis of different fruit juices, and figures are presented for the accuracy and reproducibility of the recommended procedures.

The method described can be used for the dissolution and determination of major and minor constituents in a wide range of compositions of siliceous materials. A pressure dissolution vessel is used for fast and complete acid attack. The principle solvent is hydrofluoric acid, but boric acid is added after dissolution to complex excess of hydrofluoric acid and dissolve precipitated fluorides. A second heating step is shown greatly to improve the efficiency of this process.Most inter-element interferences are removed in the presence of the fluoroboric acid so formed when the dinitrogen oxide-acetylene flame is used. Neither releasing agents such as lanthanum nor detailed matching of standards to sample compositions are therefore necessary. Both macro- and micro-scale versions of the method are given, the latter having proved satisfactory for samples as small as 10 mg, such as those commonly encountered in archaeological work.

Baculum shape and skull and body measurements were used to evaluate the forms of Eptesicus occurring in Australia. Four species, one of which comprised two subspecies, are recognized. An additional form, E. douglasi, was not intensively studied but is accepted as a full species. Names were available for all forms except one, which is described as E. sagittula, sp. nov.

A highly accurate spectrophotometric determination of major components in oxides and oxide mixtures with a Unicam SP3000 automatic ultraviolet spectrophotometer is described. Coefficients of variation of 0·2 per cent. have been achieved and under ideal conditions, for a simple system, coefficients of variation of 0·03 per cent. are possible. Details of procedures evolved for the analysis of pre-fired ferrites are included.

Interferences in the absorption of chromium and molybdenum in steels are overcome in the nitrous oxide-acetylene flame by using perchloric acid as the solvent. The method is rapid and suitable for any level of chromium or molybdenum found in steels and other metallic alloys. An alternative method for the determination of molybdenum is necessary when the tungsten concentration exceeds 0·5 per cent.; this involves the use of a perchloric-phosphoric-sulphuric acid mixture to retain the tungsten in solution. A difference read-out technique to obtain good precision for high levels of chromium is described.

The determination, by atomic-absorption spectrophotometry, of small amounts of nickel in edible fats is described. Nickel is extracted from the samples with 10 per cent. nitric acid in the presence of carbon tetrachloride, to break the emulsion, and the aqueous layer is aspirated directly to determine the nickel. The method requires only 15 minutes for completion, and the detection limit for nickel is better than 0·1 p.p.m.