The effects of continuous flow microwave treatment and conventional heating on the nutritional value of milk as shown by influence on vitamin B1 retention

 The effects of continuous flow microwave treatment and conventional heating (using a plate heat exchanger) on the nutritional value of raw milk was estimated by measurement of the vitamin B₁ retention. Microwave heating, without a holding phase, did not modify the vitamin B₁ content of milk, whereas analogous treatment carried out with the plate heat exchanger led to a loss of this vitamin. A holding phase caused a similar loss of vitamin B₁ in milk heated using either system. These results indicate that continuous flow microwave treatment of milk compares favourably with conventional heating because it produce less destruction of vitamin B₁ in milk. This could be attributed to the shorter time taken to reach the final temperature and the lack of hot surfaces in contact with the milk in the case of the microwave system. Received: 16 October 1998     

The distribution of bibliographic records in databases using different counting methods for duplicate records

Knowing how records on a particular topic are distributed over databases is useful for both practical and theoretical reasons; however little work in this area appears to have been done. This paper examines the distribution of records on the topic of “Fuzzy Set Theory” in over 100 bibliographic databases and determines whether the distribution of records over databases is similar to the traditional Bradford hyperbolic distribution of records over journals. Different methods for counting duplicate records between and within databases have been developed. A comparison of the various distributions based on these counting methods is presented; and the distributions are compared to results of earlier studies. The results also give an indication of the number of databases necessary to search for coverage of a literature to specified percentages using the different counting techniques developed in this study.     

The use of floral characters in <Emphasis Type="Italic">Capparis</Emphasis> sect. <Emphasis Type="Italic">Capparis</Emphasis> to determine the botanical and geographical origin of capers

Capers of commerce are flower buds of Capparis species, most of them presumably of the species C. spinosa and they are considered as such in international food legislation. However, in the Mediterranean countries of Europe, Asia, and North Africa, that are the main producers of capers, four different species have been detected in the commercial product: C. spinosa, C. sicula, C. orientalis and C. aegyptia. In this paper the study of morphological characters, easily detectable under optical microscope (number of stamens, anther shape, and morphology of nectary) has proven to be a simple and cheap technique to recognize the presence of the above-mentioned species in commercial capers and the relative percentages of each, this being a good indicator of the most likely geographical origin.     

Preface

Preface

Preface     

Histochemical demonstration of two subtypes of O-linked oligosaccharides in the rat gastric glands

The gastric glands synthesize glycoproteins whose oligosaccharides are linked to the peptide core mainly by the O-glycosidic bond, specifically removed by beta-elimination procedure. Our aim was to research the possibility of the existence of two subtypes of O-linked oligosaccharides with a different behavior to the removal procedure. The lectins from peanut (PNA) and Maackia amurensis (MAA-I) were histochemically used as markers of the O-linked oligosaccharides. Sections were also pretreated with beta-elimination and/or peptide N-Glycosidase F (PNGase-F) for the specific removal of O- and N-linked oligosaccharides, respectively. The lectin GNA, which mainly labels to N-linked oligosaccharides, was used to test the correct working of PNGase-F. To test the possibility that the beta-elimination treatment could remove the terminal sialic acid residues, the lectin LFA was used. The surface epithelium was negative to PNA, while it became strongly positive when beta-elimination was performed for 1 day. This staining was resistant to PNGase-F, suggesting that PNA was labeling to O-linked oligosaccharides. However, after beta-elimination for 5 days this staining is not observed. A similar pattern appeared with MAA-I. We propose the existence of two subtypes of O-linked oligosaccharides: labile and resistant. The labile O-linked oligosaccharides are removed with beta-elimination for 1 day, unmasking the PNA-positive oligosaccharides. These oligosaccharides are resistant O-linked oligosaccharides because staining is abolished with longer treatment of beta-elimination. The results with MAA-I also support this suggestion. In summary, the labile O-linked oligosaccharides are removed with short treatment, while the resistant O-linked oligosaccharides need a stronger procedure (for 5 days).     

Designing Irreversible Inhibitors—Worth the Effort?

Despite the unquestionable success of numerous irreversible drugs that are currently in clinical use, such as acetylsalicylic acid (Aspirin) and penicillin, the number of such approved drugs is much lower than that of noncovalent drugs. Over the years, the potential off‐target effects of these types of compounds have been the primary concern that has hampered their development. However, their remarkable advantages over noncovalent drugs and a better analysis of the risks have decreased the widespread skepticism surrounding them. The design of irreversible inhibitors is a challenge, particularly considering that in some cases their efficacy is due to complex and unexpected mechanisms of action. In this review the main advantages of irreversible inhibition are summarized, and the complexity of certain covalent modification mechanisms is highlighted with selected examples.