Multiple-step melting in two-dimensional hexatic liquid-crystal films

An unexpected three-stage melting transition has been observed in two-dimensional (2D) free-standing liquid-crystal films by in situ electron-diffraction and optical-reflectivity measurements. These data suggest the existence of two phases between the 2D solid and liquid: a hexatic phase and, at a higher temperature, an intermediate liquid phase with hexatic-like positional correlations ( approximately 40 angstroms) but no long-range orientational order. Previous high-resolution heat-capacity measurements have revealed a divergent-like anomaly at the hexatic-liquid transition that sharply contradicts the predictions of 2D melting theories. The observation of an intermediate isotropic phase may alter our understanding of 2D melting and lead to reconciliation between current experiments and theories.     

Erysiphe pisi var. pisi on faba beans and other legumes in Britain

The powdery mildew Erysiphe pisi var. pisi, complete with its teleomorph, has been observed on faba beans ( Vicia faba cultivars) for the first time in Britain. It appeared in a glasshouse on Syrian lines of fodder bean and English cultivars of broad bean. It also infected tare ( Vicia sativa ) and sweet pea ( Lathyrus odoratus ), but not edible pea ( Pisum sativum ), ornamental lupin ( Lupinus polyphyllus ), French bean ( Phaseolus vulgaris ) or sainfoin ( Onobrychis viciaefolia ). Inoculations in a glasshouse showed that another strain of E. pisi var. pisi found on outdoor everlasting pea ( Lathyrus latifolius ) was also capable of affecting faba bean, and was distinguished by its ability to infect edible pea. A third strain found on outdoor ornamental lupin infected only lupin. E. pisi var. pisi was shown to be morphologically and pathogenically distinct from the Erysiphe sp. newly affecting tomatoes in Britain.     

Synthesis of uracil under conditions of a thermal model of prebiological chemistry

Uracil has been formed under thermal conditions which yield other materials of theoretical prebiochemical significance. The chemical evidence for the identity of uracil rests on chromatography, spectrography, color tests, and melting points and analyses of isolated material. The place of uracil in a scheme of biochemical origins, including carbon dioxide as an intermediate, is discussed.     

Corn‐expressed dietary phytase augments vertebral and scale mineral content in juvenile rainbow trout (Oncorhynchus mykiss)

Fishmeal (FM) is increasingly being replaced by plant proteins which are a relatively poor phosphorous source for mineralized tissues. To promote P availability plant‐based feedstuffs are supplemented with exogenous phytase. However, the effect of phytase on skeletal development in juvenile rainbow trout (Oncorhynchus mykiss) which have distinct mineral requirements is poorly understood. To address this juvenile trout were fed FM diet, a replacement feed (soybean meal, SBM) in which 50% (460 g kg^?1) of crude protein (from FM) was substituted with soybean‐meal or SBM supplemented with microbial or corn‐expressed phytase. Vertebral and scale morphology, remodelling and mineralization were then assessed by histomorphometric and colorimetric assays. Body weight and SGR of trout fed SBM was lower than FM fed fish with no improvement noted with any phytase supplement. Vertebral mineral content and autocentrum morphology were similar in trout fed SBM or FM and supplementation with microbial‐phytase did not enhance these parameters at any concentration. However, scale and vertebral mineral content were significantly enhanced in trout fed SBM supplemented with corn‐expressed phytase 1500 FTU kg^?1 (vertebral phosphorus P = 0.014, Ca P = 0.026; scale phosphorus P = 0.012). Thus, SBM feeds supplemented with corn‐expressed phytase could help reduce FM usage and generate a more robust skeleton less prone to deformity.     

Traumatic Temporal Lobe Syndrome in the Dog with Atypical Encephalitis

Abstract—The clinical, electrophysiological and histological findings in a young dog showing unusual neurological symptoms are reported. EEG recordings showed slow wave activity predominantly over the right side of the brain, while in the left fore and hind limbs constant myoclonic twitches were observed. Exploratory craniotomy disclosed no gross anomaly, but surface electrodes revealed the slow wave activity to be localized in the right temporal region. Histologic examination showed that there was a severe traumatic lesion on the right temporal lobe, accompanied by neuronal degeneration. Bacteria were found throughout the CNS and on culture were identified as Streptococcus faecalis. Résuxné—Les découvertes cliniques, électrophysiologiques et histologiques chez un jenue chien indiquant des symptǒmes neurologiques peu usuels y sont décrites. Des enregistrements EEG ont indiqué une lente activité d'onde surtout manifeste du cǒté droit du cerveau tan& que des mouve-ments convulsifs myocliniques constants se sont vérifiés sur les membres avant et arrière gauches. Une étude craniotomique n'a révélé aucune anomalie générale, mais des électrodes en surface ont indiqué que l'activité lente d'onde était localisée dans la région temporale droite. L'examen histo-logique a révélé qu'il y avait une léion traumatique sévère sur le lobe temporal de droite, accom-pagnée d'une dégénération de cellules nerveuses. L'existence de bactéries a été vérifiée à travers la CNS et mises en culture elks ont été identifiées comme étant Streptococcus faecalir. Zusammedassung—Die klinischen, elektrophysiologischen und histologischen Beobachtungen en einem jungen Hunde mit ungewöhnlichen neurologischen Symptomen werden berichtet. EEG Aufzeichnungen zeigten langsame Wellenaktivität, in der Hauptsache über der rechten Gehirnseite, während im linken Vorder- und Hinterbein konstante myoklonische Zuckungen beobachtet wurden. Diagnostische Craniotomie ergab keine wesentliche Anomalie, aber Oberflächen-elektroden zeigten an, dass die langsame Wellenaktivität in der rechten Temporalgegend lokalisiert war. Histologkche Untersuchung ergab eine schwere traumatische Veränderung des rechten Lobus temporalis mit Neuron Degeneration. Bakterien wurden im ganzen Zentralnervensystem gefunden. Deren Kultur ergab Streptococcus faecalis.     

Acid phosphatase in cheese

The combined action of proteinases/peptidases and acid phosphatases on phosphorylated proteins/peptides could be important for cheese quality. It seems that acid phosphatase activity in cheese originates from milk and microorganisms. Bovine milk contains more than one acid phosphatase, which are distributed between the cream and skim milk. The properties of two enzymes isolated from butter milk and skim milk are different. In general, acid phosphatase, especially that from starter organisms is very heat stable. The dephosphorylation of casein and phosphopeptides is of interest in cheese ripening. It has been suggested that acid phosphatases from both skim milk and lactic acid bacteria contribute to dephosphorylation of phosphopeptides in cheese, which are produced from casein by coagulant, indigenous milk proteinase and microbial proteinases during cheese ripening.     

Diethylstilboestrol—clinical pharmacology and alternatives in small animal practice

Diethylstilboestrol is currently only available in Australia for oral use in dogs and cats. As an orally and systemically active non-steroidal oestrogen, DES has been widely used in small animal veterinary medicine for a variety of indications. A review of the literature reveals that many of the recommendations for use are founded on anecdotal or unreported clinical observations. While many of the uses may be valid, accurate determinations of optimum dosing regimens have not been defined. This is especially unfortunate in view of the potential toxicity of DES to small animals. Nevertheless, particularly in cases of low-dose intermittent administration, oral DES appears indicated at least until data on alternative safe and effective interventions become available.