Assessment of bog-body tissue preservation by pyrolysis-gas chromatography/mass spectrometry

Flash pyrolysis-gas chromatography/mass spectrometry (py-GC/MS) was used to assess the quality and mechanism of protein preservation in the tissue of Iron Age bog bodies from Lindow, UK, and south-eastern Drenthe, The Netherlands. Abundant pyrolysis products of the fresh skin tissue, including 2,5-diketopiperazines of Pro-Gly, Pro-Ala, Pro-Val, Pro-Pro and Hyp, were readily assigned to specific amino acid or dipeptide moieties. Comparison of the pyrolysates of the bog-body tissues with that of modern samples revealed qualitative similarities suggesting good preservation of the collagen and non-collagenous proteins in the ancient tissues. Examination of the pyrolysates of samples of fresh calf skin, which had been treated with various vegetable tanning agents, clearly revealed markers of non-hydrolysable tannins including 1,2-benzenediol, 1,3-benzenediol and 1,2,3-benzenetriol, although chromatographic quality inevitably diminished with increasing functionalization of the compounds. Such markers were not detected in the pyrolysates of the bog-body tissues. Instead 4-isopropenylphenol, a characteristic pyrolysis product of Sphagnum moss, was detected in both solvent-extracted and base-treated samples of tissue. The presence of 4-isopropenylphenol in the pyrolysates of the bog-body tissues provides evidence that their preservation involves reactions of amino acids with sphagnum acid, and possibly other agents derived from the peat. The study constitutes the first chemical characterization of the pyrolysis products of modern and ancient collagen.     

Immobilized α-amylase from Bacillus licheniformis: a potential enzymic time—temperature integrator for thermal processing

Biphasic and nth-order models were tested as to their usefulness to fit experimental inactivation data of Bacillus licheniformis α-amylase, immobilized on glass beads, and were discussed with respect to their suitability to characterize the considered enzymic system as a time—temperature integrator (TTI) to evaluate heat processes. Both isothermal and non-isothermal inactivation experiments were carried out. Model (kinetic) parameters (rate constant k, activation energy E_A and reaction order n) were estimated using a non-linear regression procedure. The results obtained, especially the activation energy of about 293 kJ mole^–1, indicated a potential use of this system as a TTI for heating processes in the temperature range of 96–108°C.     

APPLICATION OF CONCEPTUAL LEARNING TECHNIQUES TO GENERALIZED GROUP TECHNOLOGY

Abstract

In this article, we first point out the advantages and limitations of the keywords filtering techniques and the standard automatic clustering techniques for group technology applications. We consider, then, a product, or more generally an item, as a conjunction of symbolic attributes. We present a new method to recognize homogeneous families of products and to interpret the families by extraction of their concepts. Finally, the method is applied to analyze a population of 1010 mechanical parts.     

THE LECTINS AND LECTIN-LIKE PROTEINS OF TEPARY BEANS (PHASEOLUS ACUTIFOLIUS) AND TEPARYCOMMON BEAN (PHASEOLUS VULGARIS) HYBRIDS

High levels of lectin activity were found in sixty cultivated and ten wild tepary (Phaseolus acutifolius) accessions. No lectin deficient varieties were observed and all examples studied contained both the phytohemagglutinin-E and L-like lectins previously described (Pusztai et al. 1987). There appeared to be no obvious differences between the wild and cultivated forms of the tepary lectins and all teparies studied contained lectin-like proteins in addition to the tepary lectins. One of the lectin related proteins (40 Kdalton subunit) was present in all teparies and may be comparable to arcelin, a lectin found in certain wild accessions of Phaselus vulgaris. All wild teparies contained a lectin related polypeptide of about 34 Kdaltons which appears to distinguish the wild teparies from the cultivated forms. Three tepary-common bean hybrids were examined and one hybrid was found to be expressing both tepary and common bean lectin genes.     

DC chopper with coupled-inductor commutation

A novel coupled-inductor commutation circuit is described. The circuit may also be used for inverters. It uses only two auxiliary thyristors, each operating in alternate cycles and eliminating the need for reversal of the commutating capacitor voltage. Trapped energy is fed back to the source. The output voltage is controllable from zero to the full input voltage. The commutation circuit can be connected to a voltage source other than that feeding the load. A DC chopper using this commutation scheme has been analysed and experimentally verified.     

A MARANTHUS CRUENTUS LECTIN: PURIFICATION, STABILITY, AND SOME BIOCHEMICAL PROPERTIES

Amaranth lectin from Amaranthus cruentus seeds was isolated, purified and partially characterized. The purification method used was based on its ability to interact with fetuin. Effects of temperature, pH and buffers and concentration were determined by measurement of lectin hemagglutination activity. Amaranth lectin biological activity was best maintained at temperatures between 4 and 30°C and pH's above or below 5. It was possible to store amaranth lectin at 4°C in acetate buffers, pH 4.8, for prolonged periods and to concentrate it 10-fold by ultrafiltration with only 18% loss of activity. A subunit molecular weight of 32,500 daltons was determined by SDS-PAGE for amaranth lectin.     

海拔和相对湿度对卷烟感官质量的影响

为研究不同海拔和相对湿度对卷烟评吸指标的影响,采用卷烟评吸和MBA(多层次双三次样条插值)的分析方法,在16个不同的城市分别对某品牌卷烟的感官质量(11个评吸指标)进行评价.结果表明:在不同海拔和相对湿度的影响下,卷烟感官质量表现也不尽相同.海拔在0～1000 m之间,湿度在30%～50%或60%～80%时,香气特性(香气韵调、香气量、香气质)表现较好;在海拔200～700 m时,相对湿度为60%～80%时,烟气特性(浓度)较高;而海拔在0～1000 m之间,湿度60%～80%时,口感特性(刺激、烟气湿润度、干净度、回味)表现较好;海拔在1000 m以下,感官质量总体较好,且湿度为30%～50%或60%～80%时,感官质量表现最好.     

Usefulness of chromosome examination in the diagnosis of malignant pleural effusions

To determine whether chromosome analysis could facilitate the diagnosis of malignant pleural effusions, we examined chromosomes in effusions from 104 unselected patients. An effusion was regarded as malignant if at least three of 30 metaphase cells were hyperdiploid or contained a marker chromosome. Results were compared with standard cytologic diagnoses. All 22 benign effusions were diagnosed correctly by cytologic examination, but one nosed correctly by cytologic examination, but one (acute rheumatoid lung disease) was misclassified as positive by chromosome criteria. Of the 82 malignant effusions, 53 (65 per cent) were diagnosed correctly by cytologic tests, as compared with 58 (71 per cent) by chromosome analysis (P greater than 0.2). Among patients with malignant neoplasms, 13 had leukemia or lymphoma; only four of these (31 per cent) were diagnosed by cytologic tests as compared with 11 (85 per cent) by chromosome analysis (P less than 0.01). The combination of standard cytologic and chromosome analyses correctly identified 83 per cent of the neoplasms, a result significantly better than that with either technic alone (P less than 0.01).