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We explored the geological history of the Taurus‐Littrow Valley at the Apollo 17 landing site through the induced thermoluminescence (TL) properties of regolith samples collected from the foothills of the Northern and Southern Massifs, from near the landing site, and from the deep drill core taken in proximity to the landing site. The samples were recently made available by NASA through the Apollo Next Generation Sample Analysis program in anticipation of the forthcoming Artemis missions. We found that the two samples from the foothills of the massifs exhibit induced TL values approximately four times higher than those of the valley samples. This observation is consistent with their elevated plagioclase content, indicating their predominantly highland material composition. Conversely, the valley samples display induced TL values characteristic of lunar mare material. The samples from the deep drill core demonstrate uniformly induced TL properties, despite originating from depths of up to 3 m. Notably, one of the samples from the lower section of the deep drill core presents anomalous‐induced TL readings. This anomaly coincides with elevated levels of low‐potassium KREEP along with reduced quantities of anorthositic gabbro and orange glass, and could be due to the traces of phosphate minerals. Alternatively, this observation raises the possibility that this sample contains Tycho impact material. The induced TL data is consistent with the regolith, extending to a depth of at least 3 m, having been deposited by a singular event approximately 100 million years ago. This timing aligns with the hypothesized formation of the Tycho crater. We studied the geologic history of the Taurus‐Littrow Valley through the induced thermoluminescence (TL) properties of Apollo 17 regolith samples. Thermoluminescence refers to the light emission of a sample when it is heated. Our investigation focused on samples that were collected from the foothills of the Northern and Southern Massifs, from near the landing site, and from the deep drill core taken in proximity to the landing site. We found that samples from the foothills of the massifs induced TL levels four times higher than those from the valley floor. We attribute this difference to their differing plagioclase content, whereby the TL of foothill samples is comparable to highland material, and valley floor TL is comparable to mare material. The induced TL properties in the deep drill core are mostly uniform. However, one of the samples within the lower section of the deep drill core exhibited anomalous‐induced TL levels. This coincides with elevated levels of low‐potassium KREEP along with reduced quantities of anorthositic gabbro and orange glass, which could be due to traces of phosphate minerals. Alternatively, this sample may contain Tycho impact material. Our TL data suggest that the valley floor regolith was deposited by a single event approximately 100 million years ago, aligning with the hypothesized formation of the Tycho crater. The samples from the deep drill core demonstrate uniformly induced TL propertiesThe TL anomaly in the lower section of the deep drill core coincides with elevated KREEP level. Alternatively, anomalies may represent Tycho materialTL data suggest deposition of valley regolith of at least upper 3 m during a single event, potentially 100 Mya during Tycho impact The samples from the deep drill core demonstrate uniformly induced TL properties The TL anomaly in the lower section of the deep drill core coincides with elevated KREEP level. Alternatively, anomalies may represent Tycho material TL data suggest deposition of valley regolith of at least upper 3 m during a single event, potentially 100 Mya during Tycho impact

Background:Obesity induces significant changes in lipid mediators, however, the extent to which these changes persist after weight loss has not been investigated.Subjects/Methods:We fed C57BL6 mice a high-fat diet to generate obesity and then switched the diet to a lower-fat diet to induce weight loss. We performed a comprehensive metabolic profiling of lipid mediators including oxylipins, endocannabinoids, sphingosines and ceramides in key metabolic tissues (including adipose, liver, muscle and hypothalamus) and plasma.Results:We found that changes induced by obesity were largely reversible in most metabolic tissues but the adipose tissue retained a persistent obese metabolic signature. Prostaglandin signaling was perturbed in the obese state and lasting increases in PGD2, and downstream metabolites 15-deoxy PGJ2and delta-12-PGJ2were observed after weight loss. Furthermore expression of the enzyme responsible for PGD2synthesis (hematopoietic prostaglandin D synthase, HPGDS) was increased in obese adipose tissues and remained high after weight loss. We found that inhibition of HPGDS over the course of 5 days resulted in decreased food intake in mice. Increased HPGDS expression was also observed in human adipose tissues obtained from obese compared with lean individuals. We then measured circulating levels of PGD2in obese patients before and after weight loss and found that while elevated relative to lean subjects, levels of this metabolite did not decrease after significant weight loss.Conclusions:These results suggest that lasting changes in lipid mediators induced by obesity, still present after weight loss, may play a role in the biological drive to regain weight.

Abstract—In order to explore the nature and history of micrometeorites, we have measured the thermoluminescence (TL) properties of four micrometeorites, three cosmic spherules, and one irregular scoriaceous particle, that we found in a survey of 17 micrometeorites. These micrometeorites have TL sensitivities ranging from 0.017 ± 0.002 to 0.087 ± 0.009 (on a scale normalized to 4 mg of the H3.9 chondrite Dhajala). The four micrometeorites have very similar TL peak temperatures and TL peak widths, and these distinguish them from CI, most CM, CV, CO, and ordinary chondrites. However, the TL properties of these micrometeorites closely resemble those of the unusual CM chondrite MacAlpine Hills (MAC) 87300 and terrestrial forsterites. Heating experiments on submillimeter chips of a CM chondrite and a H5 chondrite suggest that these TL properties are have not been significantly affected by atmospheric passage. Thus we suggest that there is no simple linkage between these micrometeorites and the established meteorite classes, and that forsterite is an important component of these micrometeorites, as it is in many primitive solar system materials.

The formation of two aluminophosphate frameworks, AlPO4-5 and AlPO4-18, has been monitored using hyperpolarized ¹²⁹Xe NMR as a probe. The reaction progress from an amorphous phase to AlPO4-5 and its subsequent conversion to AlPO4-18 is observed for xenon adsorbed in samples that have been reacted for varying lengths of time. The extreme sensitivity of ¹²⁹Xe chemical shifts to local environments of the xenon leads to separate NMR peaks for xenon adsorbed in the two different aluminophosphate frameworks present in a single reaction mixture. For xenon adsorbed in AlPO4-5, an anisotropic ¹²⁹Xe NMR line shape at δiso ≈ 63 ppm is observed, whereas for xenon in AlPO4-18, a peak with a small anisotropy at δiso ≈ 74 ppm is observed. Grand canonical Monte Carlo simulations provide a theoretical description of xenon adsorbed in the two aluminophosphate frameworks, and the resulting simulated ¹²⁹Xe NMR line shapes are in good agreement with experimental data. Two-dimensional exchange NMR spectroscopy was used to examine the exchange of xenon between AlPO4-5, AlPO4-18, and bulk xenon gas. The results indicate that the domains of AlPO4-5 are in intimate contact with those of AlPO4-18, facilitating a higher intercrystallite exchange than with the bulk xenon gas.

Abstract—The study of chondrules provides information about processes occurring in the early solar system. In order to ascertain to what extent these processes played a role in determining the properties of the enstatite chondrites, the physical and chemical properties of chondrules from three EL3 chondrites and three EH3 chondrites have been examined by optical, cathodoluminescence (CL), and electron microprobe techniques. Properties examined include size, texture, CL, and composition of both individual phases and bulk chondrules. The textures, distribution of textures, and composition of silicates of the EL3 chondrules resemble those of EH3 chondrules. However, the chondrules from the two classes differ in that (1) the size distribution of the EL chondrules is skewed to larger values than EH chondrules, (2) the enstatite in EL chondrules displays varying shades of red CL due to the presence of fine‐grained sulfides and metal in the silicates, and (3) the mesostasis of EH chondrules is enriched in Na relative to that of EL chondrules. The similarities between the chondrules of the two classes suggest similar precursor materials, while the differences suggest that there was not a single reservoir of meteoritic chondrules, but that their origin was fairly local. The differences in the size distribution of chondrules in EH and EL chondrites may be explained by aerodynamic and gravitational sorting during accumulation of the meteoric material, while differences in CL and mesostasis properties may reflect differences in formation conditions and cooling rate following chondrule formation. We argue that our observations are consistent with the formation of enstatite chondrites in a thick dynamic regolith on their parent body.

Abstract—We review induced thermoluminescence (TL) data for 102 unequilibrated ordinary chondrites (UOCs), many data just published in abstracts, in order to identify particularly primitive UOCs and further explore TL systematics that may have implications for the history of the chondrites and their parent body. We have identified 11 UOCs of petrologic types 3.0–3.1: Adrar 003, Elephant Moraine (EET) 90066, EET 90161, Grosvenor Mountains (GRO) 95502, Lewis Cliff (LEW) 88477, Meteorite Hills (MET) 96503, Yamato (Y)‐790787, Y‐791324, Y‐791558, Y‐793565, and Y‐793596. These samples represent an important new resource for researchers interested in the nature of primitive solar system materials. Previously reported trends in which TL sensitivity increases with TL peak temperature and TL peak width, which we interpret in terms of crystallization of feldspar in the ordered or disordered forms during metamorphism, are confirmed by the new data. Importantly, the present data strengthen the trend described earlier in which the mean level of metamorphism experienced by UOCs increases along the series LL, L and H. This suggests either different burial depths for the UOCs from each class, or formation at similar depths in regoliths of different thickness.

Abstract—We measured cosmic‐ray products—noble gases, radionuclides, thermoluminescence, and nuclear tracks—and trace element contents and mineralogy of samples of three orthogonal and mutually intersecting cores (41–46 cm long) of a 101.6 kg Ghubara individual (1958,805) at The Natural History Museum, London. The xenoliths, like the host, have high concentrations of trapped solar gases and are heavily shocked. While contents of noble gases and degree of shock‐loading in this individual and three others differ somewhat, the data indicate that Ghubara is a two‐generation regolith breccia. Contents of cosmogenic 26Al and 10Be and low track densities indicate that the Ghubara individuals were located more than 15 cm below the surface of an 85 cm meteoroid. Because of its large size, Ghubara's cosmic‐ray exposure age is poorly defined to be 15–20 Ma from cosmogenic nuclides. Ghubara's terrestrial age, based on 14C data, is 2–3 ka. Not only is Ghubara the first known case of a two‐generation regolith breccia on the macroscale, it also has a complicated thermal and irradiation history.

Principal component analysis and singular value decomposition (PCA and SVD) with self-modeling (SM) based on the van't Hoff equation constraint, were applied to 1,3-butadiene UV spectra measured in the 5.0−93.0 °C range. The shape of the resolved UV spectrum of the high-energy conformer of 1,3-butadiene is sensitive to broadening of the spectra of the individual conformers with increasing T. A simulated spectral set, in which temperature broadening was purposely included, was used to develop a procedure that allows precise recovery of the pure component spectra. A set of Gaussians is derived that, on convolution with the spectrum for each corresponding T, creates a uniformly broadened spectral set. Exact recovery of the “s-cis spectrum” from the simulated spectral set is accomplished. Treatments of the experimental spectra using this method yields a minor conformer 1,3-butadiene spectrum that is only slightly red-shifted relative to the s-trans-1,3-butadiene spectrum and is consistent with the s-gauche structure. Application of PCA-SM to the onsets of the simulated spectral set showed that temperature broadening does not significantly alter the conformer enthalpy difference derived from the best-fit van't Hoff plot (compare 3.00000 kcal/mol assumed with 2.99992 kcal/mol recovered). The experimental onset spectra give ΔH° = 2.926 kcal/mol, in excellent agreement with previously reported values.

Sequential immunoprecipitates show that H-2dm1 mutant cells express a hybrid "H-2D/L" antigen exhibiting determinants normally associated with two different gene products of the parental d haplotype-i.e., the H-2Dd and H-2Ld antigens. The hybrid H-2D/Ldm1 antigen appears to consist of a portion of the NH2-terminal extracellular half of the H-2Dd antigen "fused" to a portion of the COOH-terminal extracellular half of the H-2Ld antigen. This structure is inferred from the reactivity of dm1 antigens with cytotoxic T lymphocytes specific for H-2Ld determinants and with monoclonal antibodies specific for determinants in the structural domains of H-2Ld or H-2Dd. The H-2D/Ldm1 molecule apparently retains all of the third external domain (C2 or alpha 3) and part of the second external domain (C1 or alpha 2) of H-2Ld, but its first external domain (N or alpha 1) derives from H-2Dd. From these findings and from previous peptide mapping studies, we propose that the H-2D/Ldm1 antigen is the product of a hybrid gene that has resulted from an unequal crossover between the parental H-2Dd and H-2Ld genes, leaving the N exon and part of the C1 exon of the H-2Dd gene joined to the H-2Ld gene beginning somewhere within its C1 exon.

Fly ash has been collected from the baghouse of an experimental atmospheric fluidized bed combustor (AFBC) burning Beulah, N.D., lignite. The bulk ash has been size-separated after collection, and chemical analyses have been performed on the largest fraction, which had a mass median diameter of 2.μm. This lignite AFBC ash lacks the predominant aluminosilicate core characteristic of fly ash from the combustion of pulverised bituminous coal. Instead, it consists primarily of calcium carbonate. It appears that a large fraction of the ash is derived from the limestone bed material, rather than from the lignite fuel. The bulk concentrations of trace metals are within normal ranges, although the enrichment factors for Mn, Cr, Mg, Ni, K, and Ca are exceptionally large.

We have developed a system that utilizes human DNA-derived yeast artificial chromosomes (YACs) as marker chromosomes to study factors that contribute to the fidelity of meiotic chromosome transmission. Since aneuploidy for the YACs does not affect spore viability, different classes of meiotic missegregation can be scored accurately in four-viable-spore tetrads including precocious sister separation, meiosis I nondisjunction, meiotic chromatid loss, and meiosis II nondisjunction. Segregation of the homologous pair of 360-kilobase marker YACs was shown to occur with high fidelity in the first meiotic division and was associated with a high frequency of recombination within the human DNA segment. By using this experimental system, a series of YAC deletion derivatives ranging in size from 50 to 225 kilobases was analyzed to directly assess the relationship between meiotic recombination and meiosis I disjunction in a genotypically wild-type background. The relationship between physical distance and recombination frequency within the human DNA segment was measured to be comparable to that of endogenous yeast chromosomal DNA--ranging from less than 2.0 to 7.7 kilobases/centimorgan. Physical analysis of recombinant chromosomes detected no unequal crossing-over at dispersed repetitive elements distributed along the YACs. Recombination between YACs containing unrelated DNA segments was not observed. Furthermore, the segregational data indicated that meioses in which YAC pairs failed to recombine exhibited dramatically increased levels of meiosis I missegregation, including both precocious sister chromatid separation and nondisjunction.

Abstract: Fluorescence spectra of trans-1-(2-anthryl)-2-phenylethene (APE) obtained under varying conditions of excitation wavelength and oxygen concentration in toluene are resolved into two distinct components by application of principal component analysis with self-modeling (PCA-SM). Self-modeling is guided by the constraint that Stem-Volmer quenching plots for the individual conformers be independent of excitation wavelength. The same process applied on a matrix of fluorescence-excitation spectra leads to resolved conformer-specific fluorescence-excitation spectra. Consistency between the fluorescence and the fluorescence-excitation spectrum of each conformer is established. The fluorescence-excitation spectr and literature fluorescence quantum yields are used to resolve the UV absorption spectrum of APE. The pure conformer spectra obtained in this work are compared with those from earlier PCA-SM treatments in which self-modeling procedures were based on the Lawton and Sylvestre nonnegativity constraint and on a maximal spectral dissimilarity constraint.

Significant cytotoxic lymphocyte-induced DNA fragmentation does not occur in four human target cells lysed by human natural killer lymphocytes, killer lymphocytes, or cytotoxic T lymphocytes. These results contrast with the extensive DNA fragmentation that occurs in murine target cells lysed by the analogous effector lymphocytes. Thus, DNA fragmentation, or the lack thereof, represents a species-specific difference between human and murine cells responding to lysis by cytotoxic lymphocytes. The DNase activity observed in murine cells is probably internally activated rather than delivered by the cytotoxic effector cells, since human killer lymphocytes selectively caused DNA fragmentation in murine but not in human target cells lysed by antibody-dependent cellular cytotoxicity.

A cDNA clone for an IgG-binding Fc receptor, rtFc gamma R alpha, of the rat natural killer cell line CRNK-16 is characterized here. This clone encodes an Fc gamma receptor as shown by the ability of cDNA-transfected COS cells to rosette IgG-coated sheep erythrocytes. The rtFc gamma R alpha is exceptionally homologous to the mouse moFc gamma R alpha, with 77% protein sequence identity and 71% nucleic acid identity overall. The transmembrane region of the rtFc gamma R alpha contains the sequence Leu-Phe-Ala-Val-Asp-Thr-Gly-Leu, which is present in the membrane sequences of four other Fc receptors including mouse Fc gamma R alpha, human Fc gamma RIII-2, and the Fc epsilon R alpha subunits of the rat and human high-affinity IgE-binding receptors. Also, the rtFc gamma R alpha cytoplasmic domain exhibits specific homology to other receptors derived from natural killer cells, human Fc gamma RIII-2 and mouse Fc gamma R alpha. However, the rtFc gamma R alpha cDNA clone is complementary to at least two different-sized mRNAs expressed by CRNK-16 cells, contrasting the single Fc gamma R-related mRNA species expressed by human and mouse natural killer cells. These rat mRNAs are homologous to both the 5' and the 3' end of the cDNA clone, suggesting that they may be (i) splice variants of one transcript or (ii) products of different but highly related genes.

After reduction by dithiothreitol and removal of the reductant by molecular sieve chromatography, the four interchain disulfide bonds of the human IgGlk protein Fro reoxidize in the presence of oxygen and trace metal ions. The six molecular components of the reoxidation--L (light chain), H (heavy chain), HL, H2, H2L, H2L2--are quantitatively determined from polyacrylamide gels containing sodium dodecyl sulfate and the time-dependent sulfhydryl titer is measured with 5,5'-dithiobis-(2-nitrobenzoic acid). The rates of H2L2 covalent assembly depend on pH in an unexpected way: If the reduced protein is chromatographed at pH 3.2 and then adjusted to pH 7.5 (25 degrees, ionic strength equals 0.14), H2L2 formation proceeds rapidly, with half-times ranging between 20 and 40 min. In contrast, if chromatography is carried out at pH 5.5 before adjusting to the same final conditions, the half-times for H2L2 formation are considerably longer (120-180 min). The half-times in the former case approach the somewhat faster rates of H2L2 assembly observed in pulse-chase experiments with various types of mouse, IgG-producing cells [Baumal, et al. (1971) J. Exp. Med. 134, 1316-1334]. To facilitate comparison of experiments and models, we plot the concentrations of the six components against the corresponding number of sulfhydryl equivalents per mole of Fro. The respective plots for the pH 3.2 leads to 7.5 and 5.5 leads to 7.5 experiments are very similar despite the rate differences. Moreover, these plots differ significantly from the calculated plot for a hypothetical random reoxidation in which the intrinsic probability for formation of each correct HL and H2 disulfide bond is assumed equal and independent. It is concluded that the in vitro reoxidation of Fro (i) is other than random; (ii) involved a pathway of pathways with HL, H2, and H2L precursors; and (iii) involves at least some kinetic cooperativity in bond formation, since no model bases solely on independent bond formation adequately accounts for the results. The models were used also to examine the cellular assembly pathways of mouse IgG proteins.

A thermoluminescence sensitivity technique is used to give a new measurement of the degree of metamorphism of unequilibrated ordinary chondrites. Consequently the petrological assignment of these meteorites is modified.

The mutagenicity of a benzene/methanol extract of fly ash from an atmospheric fluidized-bed combustor burning Beulah, N.D., lignite was tested in Salmonella. Six strains were used, including three that were mutants in a nitroreductase gene locus. The numbers of revertants from his- to his+ as a function of the amount of fly ash extracted were determined. The results showed that the major mutagens in the crude extract were nitro compounds, from the fact that reversion rates in the nitroreductase-deficient strains were significantly lower than in the parent strains from which they were derived. The responses of the three parental strains, TA 1538, TA98, and TA 100, were quite similar; thus no conclusions could be made about frameshift versus base-substitution mutagens. Mutagenicity of 15 fractions of the extract was also tested, and one major peak of activity was detected. This activity eluted from a high-performance liquid chromatograph outside the range of retention times associated with mononitro-aromatics. No further identification of specific nitroorganic compounds has been made.

The cDNA for the common \Mac-1 subunit (CD11b) of the mouse LFA-1/Mac-1/p150,95 group of leukocyte cell adhesion receptors, formally designated integrin \2, has been cloned and sequenced. Clones were isolated from cDNA libraries made from J774 macrophage and WEHI-3B myelomonocytic tumor cells which express this subunit as a component of the macrophage activation antigen 1 (Mac-1), also known as complement receptor type 3 (CR3). This subunit is expressed as a single, abundant mRNA species approximately 2.7 kilobase (kb) in size. The 2422 base pair (bp) cDNA sequence obtained codes for a 771 amino acid protein organized with leader, extracellular, transmembrane, and cytoplamic domains of 23, 680, 23, and 46 amino acids, respectively, yielding an 82700 mature protein of 747 amino acids. The mouse \Mac-1 subunit is highly similar to its human counterpart with an overall sequence identity of 81% and identical positioning of 5 out of 6 potential N-linked glycosylation sites, as well as 56 Cys residues that are organized in repeating motifs characteristic of integrin \ subunits. The most highly conserved regions are the transmembrane and cytoplasmic domains where only 4 out of 69 amino acids differ, indicating that the functions associated with this domain in Mac-1-mediated processes, such as iC3b-triggered phagocytosis, have been evolutionarily conserved.

This paper treats design of the built environment as a decision process and asserts the need for a more objective base for design decisions. A conceptual review of the designer's problem acknowledges the difficulty of resolving multiple objectives and considers the nature of the information available to the decisionmaker. The designer's formal design evaluation is related to the informal evaluations of the eventual users of his product. Users' responses are physiological, behavioural, and attitudinal. It is argued that the accumulating understanding of attitudinal responses to the built environment constitutes a potentially valuable information base for the designer's own evaluative decisions.

The quenching of trans-1-(2-anthryl)-2-phenylethene (t-APE) fluorescence by fumaronitrile (FN) was determined as a function of excitation wavelength (λexc) and temperature (5.0 ≤ T ≤ 80.0 °C). Principal component analysis with self-modeling (PCA-SM) was applied separately to the fluorescence spectra at each temperature. Resolved pure conformer fluorescence spectra were based on the condition that Stern−Volmer quenching constants for each conformer be λexc-independent. A shoulder at the blue edge of the spectra of the more extended, s-trans conformer (t-APEB) becomes more pronounced with increasing temperature revealing fluorescence from a thermally populated S2 state. Similar, but more subtle changes are evident in the spectra of the s-cis conformer (t-APEA). Both sets of resolved spectra exhibit blue shifts and broadening as the temperature is increased. These spectral changes are reflected in the shape of the eigenvectors obtained from the PCA of each set of spectra and prevent their resolution into S2 → S0 and S1 → S0 components. An earlier PCA-SM based resolution of a t-APE spectrothermal matrix into S1 → S0 fluorescence of t-APEA and S2 → S0, S1 → S0 fluorescence spectra of t-APEB is evaluated.

This paper introduces the theoretical basis for investigating obsolescence that has resulted from the preliminary stage of an ongoing research programme. A specification for model building is included.

A model is presented suggesting the interaction of CO2 and bicarbonate on lipids of the cell membrane. The interfacial tensions between water and oil (benzene) phases were measured using the stalagmometer and the sessile drop methods. Effects of electrolyte solutions and of CO2 on molecular arrangement at the interface were calculated. Chloride solutions against oleic acid in benzene produced little decrease in interfacial tension from that measured for pure water against the oil phase. Presence or absence of CO2 caused no change in interfacial tension of water or chloride solutions against the oil phase. Bicarbonate salts in the absence of CO2 caused marked decreases in interfacial tension from that measured for water or chloride solutions. Concomitant with this decrease in interfacial tension were an increase in hydration of the interface and changes in molecular spacings of the lipid. This hydration may be considered as reflecting a more ionic-permeable cell membrane. The addition of CO2 to the bicarbonates caused an increase in interfacial tension of the model, approaching that of the chlorides, with decreased hydration of the interface. Viewed as occurring at the cell membrane this would make the lipid more continuous and decrease the ease of ionic penetration. In this way the action of bicarbonates and CO2 at the interface suggests an explanation of the action of CO2 on the cell.

The hypothesis presented in this report is that the ratio of oxygen extracted (VO2) per unit volume of alveolar ventilation (VA), or its numerical equivalent, the fraction of inspired oxygen minus the fraction of alveolar oxygen, is a significant measure of pulmonary function in children. Despite the fact that the arterial blood gases of children are within the normal range for adults, the values for the alveolar gases are significantly different. Measurements of these gases in 348 normal school children (ages 6 to 12 years) gave a higher fraction of alveolar oxygen (0.16) and a lower fraction of alveolar CO2 (0.042) than for 101 medical studients (ages 20 to 28 years). The ratio of the volume of oxygen extracted per unit volume of alveolar ventilation was significantly lower (46 ml per liter) for children than for the medical students (69 ml per liter). We suggest that this resistance to the movement of oxygen into the blood from the alveoli is an important parameter to examine in determining the effect of drugs on pulmonary function, since it represents the total effect of pulmonary ventilation, blood perfusion through the lungs, and utilization of oxygen by the tissues.

This discussion reviews some of the studies that relate interfacial phenomena to transfer of material across interfaces in both physical chemical and biological systems. The studies mentioned include: the effect of pH differences between the interface and the bulk medium; the requirement for a large negative entropy of activation for transfer between phases; the resistance to transfer of water and salts produced by monolayers of phospholipids; facillitation of lipid transfer based upon the formation of hydrophilic oleomicelles; the facilitation of transfer of molecular aggregates when these aggregates are changed from crystalline to amorphous associations; and finally, the role of chemical reactions to facilitate transfer.

The effects of four phenothiazines at 10−4 M concentration on monolayers of lecithin, cholesterol and mixed monolayers of lecithin and cholesterol were examined using surface chemical techniques. These phenothiazines produced expansion of the area per monolayer molecule at low surface pressure, facilitated the disruption of the monolayers from the water substrate at high surface pressures, increased the surface viscosity of the monolayers, and decreased the surface potentials. The data suggest that the site of action of these agents is immediately beneath the monolayers.

Chondritic meteorites are widely regarded as a unique source of information on the chemical and physical processes that occurred in the early Solar System. An important phase in their history is a period of metamorphism1and thermoluminescence (TL) has proved a powerful technique for exploring this aspect, especially at the low end of the metamorphic spectrum2. The ordinary chondrites as a whole display a 105-fold range in TL sensitivity, while the least metamorphosed, or type 3, ordinary chondrites display a 103-fold range. Associated with this 103-fold range in TL sensitivity are variations in the temperature at which the maximum TL emission occurs, and in the temperature range over which emission occurs3,4. We report here the results of annealing experiments on a little-metamorphosed (type 3.5) ordinary chondrite. The TL emission characteristics of the annealed samples show trends very similar to those observed in meteorites which have naturally been metamorphosed to various extents. The trends are also similar to those observed in annealing experiments on terrestrial albite5–7where the changes are associated with the low-to high-temperature transformation. These data suggest that the TL phosphor in meteorites is feldspar and that TL can be used to estimate palaeotemperatures for little-metamorphosed and highly-unequilibrated meteorites.

WE have made a detailed study of the metal phases in some chondrites. Axon and Goldstein have reported1micro-probe measurements of the Ni and Co contents at the interfaces between contiguous α and γ phases in seven metallic particles of high Co content from Apollo 14 and 15 lunar soils. The three particles of highest Co content had α phase in contact with clear homogeneous γ phases (Fig. 1), whereas the particles of lower Co content (Fig. 1) had Widmanstãtten spindles of α phase in a matrix of high Ni γ phase in a manner analogous to that observed in certain Ni-rich ataxite irons. Axon and Goldstein have expressed the view that the Co contents of these particles are “higher than the meteorites of similar structure” and that they must have come from a different source.

THE terrestrial age of a meteorite is the number of years which has elapsed since the meteorite fell to Earth. The terrestrial ages of most meteorites are not known directly, as most are ‘finds’ rather than observed ‘falls’. Here we discuss the various methods which have been suggested to determine the terrestrial age of the ‘finds’, and these may be conveniently divided into two categories: (1) those which use the decay of spallation-produced radioactive isotopes1–4; (2) those which use the thermal drainage of thermoluminescence (TL) from the material5,6.

THE thermoluminescence (TL) properties of meteorites1–4may be applicable to the determination of exposure age, terrestrial age, thermal gradients, radiation history and preatmospheric shape. In an attempt to apply TL to the determination of terrestrial age we have discovered that meteorites can be divided into two groups, the existence of which is relevant to several of the applications.

Abstract—A new 2.8 kg meteorite find from the United States, Kansas University, is classified as an L6 (S3) chondrite based on optical microscopy and electron microprobe analysis of mafic minerals. Natural thermo‐luminescence (TL) and 14C measurements suggest that the Kansas University meteorite has a short terrestrial age compared to other meteorite finds from this area and is not paired with the other local meteorite finds, Densmore (1879), Lawrence, Kansas and Long Island, Kansas.