The priority of internal symmetries in particle physics

In this paper, I try to decipher the role of internal symmetries in the ontological maze of particle physics. The relationship between internal symmetries and laws of nature is discussed within the framework of “Platonic realism.” The notion of physical “structure” is introduced as representing a deeper ontological layer behind the observable world. I argue that an internal symmetry is a structure encompassing laws of nature. The application of internal symmetry groups to particle physics came about in two revolutionary steps. The first was the introduction of the internal symmetries of hadrons in the early 1960s. These global and approximate symmetries served as means of bypassing the dynamics. I argue that the realist could interpret these symmetries as ontologically prior to the hadrons. The second step was the gauge revolution in the 1970s, where symmetries became local and exact and were integrated with the dynamics. I argue that the symmetries of the second generation are fundamental in the following two respects: (1) According to the so-called “gauge argument,” gauge symmetry dictates the existence of gauge bosons, which determine the nature of the forces. This view, which has been recently criticized by some philosophers, is widely accepted in particle physics at least as a heuristic principle. (2) In view of grand unified theories, the new symmetries can be interpreted as ontologically prior to baryon matter.     

The choroid in the eye of the eel (Anguilla anguilla)

Summary By means of light and scanning electron microscopy evidence of the existence of a normally organized choroid in the eye of the eel,Anguilla anguilla, is presented.     

The roles of poly(ADP-ribose)-metabolizing enzymes in alkylation-induced cell death

Poly(ADP-ribose) (PAR) has been identified as a DNA damage-inducible cell death signal upstream of apoptosis-inducing factor (AIF). PAR causes the translocation of AIF from mitochondria to the nucleus and triggers cell death. In living cells, PAR molecules are subject to dynamic changes pending on internal and external stress factors. Using RNA interference (RNAi), we determined the roles of poly(ADP-ribose) polymerases-1 and -2 (PARP-1, PARP-2) and poly(ADP-ribose) glycohydrolase (PARG), the key enzymes configuring PAR molecules, in cell death induced by an alkylating agent. We found that PARP-1, but not PARP-2 and PARG, contributed to alkylation-induced cell death. Likewise, AIF translocation was only affected by PARP-1. PARP-1 seems to play a major role configuring PAR as a death signal involving AIF translocation regardless of the death pathway involved. Received 7 November 2007; received after revision 19 December 2007; accepted 21 December 2007 O. Cohausz, C. Blenn: These two authors contributed equally to this work.     

The role of pyrophosphate and alkaline phosphatase in skin calcification (calciphylaxis)

Zusammenfassung Durch KMnO₄-Injektionen hervorgerufene lokale Hautverkalkung kann durch Pyrophosphatinjektionen verhindert werden. Durch alkalische Phosphatase wird die Pyrophosphatwirkung aufgehoben.     

The evolution of duplicate gene expression in the carp (Cyprinus carpio)

Summary The carp, Cyprinus carpio (Teleostomi), is a tetraploid species which currently expresses 52% of its duplicate enzyme loci. This level of duplicate gene expression in this cyprinid species is comparable to those observed in tetraploid Catostomidae, but higher than those in tetraploid Cobitidae.This research was supported by NSF grants GB 43995 and PCM 76-08383 to G.S.W. and by a Cell Biology Traineeship to S.D.F.We thank Suzanne Fisher and Dave Philipp for their helpful comments.     

中国铁路智能化行车制式的系统分析

本文在借鉴国内外有关先进经济的基础上,对铁路智能化行车制式系统的系统工作原理、系统内涵、设计原则、系统构架等做了较为详细的论述。     

The effect of N-(2-hydroxyethyl)-palmitamide on delayed hypersensitivity in guinea-pig

Zusammenfassung Die Wirkung von N-(2-hydroxyethyl)palmitamid auf den Verlauf der Überempfindlichkeit des Spättypes in Meerschweinchen wurde verfolgt und festgestellt, dass die Verabreichung dieses Stoffes vor der Sensibilisierung eine Stimulation der Hypersensitivität bewirkt.     

The potency of male accessory gland material in the mosquito (Aedes aegypti)

Summary Injections of male accessory gland material fromAedes aegypti into the hemocoeles of virgin female mosquitoes indicate that the potency of the secretion is equivalent to the amount of semen which a male normally places within the female. This estimation is far less than had been previously calculated. It is suggested that the termmatrone for male accessory gland material is inappropriate since it does not convert a maid into a matron but prevents reinsemination of an impregnated female.Scientific Article No. A2098, Contribution No. 5054 of the Maryland Agricultural Experiment Station.     

The role of LamininB2 (LanB2) during mesoderm differentiation in Drosophila

In Drosophila, four genes encode for laminin subunits and the formation of two laminin heterotrimers has been postulated. We report the identification of mutations in the Drosophila LamininB2 (LanB2) gene that encodes for the only laminin γ subunit and is found in both heterotrimers. We describe their effects on embryogenesis, in particular the differentiation of visceral tissues with respect to the ECM. Analysis of mesoderm endoderm interaction indicates disrupted basement membranes and defective endoderm migration, which finally interferes with visceral myotube stretching. Extracellular deposition of laminin is blocked due to the loss of the LanB2 subunit, resulting in an abnormal distribution of ECM components. Our data, concerning the different function of both trimers during organogenesis, suggest that these trimers might act in a cumulative way and probably at multiple steps during ECM assembly. We also observed genetic interactions with kon-tiki and thrombospondin, indicating a role for laminin during muscle attachment.     

The occurrence of an intermediate didelphid karyotype in the short-tailed opossum (GenusMonodelphis)

Resumen Se han estudiado los cromosomas de dos especies de didélfidos del géneroMonodelphis: M. brevicaudata palliolata del norte de Venezuela yM. dimidiata de la Prov. de Buenos Aires, Argentina. Ambas especies tienen un cariotipo muy similar, compuesto de 18 cromosomas. Este cariotipo es intermedio entre el que presentanCaluromys yMarmosa (2n=14) y el deDidelphis, Philander yLutreolina (2n=22). Se postula la fisión céntrica en dos pares de submetacentricos del primer tipo, para explicar el origen del cariotipo deMonodelphis.     

The diploid deoxyribonucleic acid (DNA) content of basal cell carcinomas in man

Zusammenfassung Der Desoxyribonukleinsäuregehalt ist bei Basalzellkarzinomen diploid im Tumor selbst, weicht jedoch bei invadierenden Stellen nach Diploidie ab.     

The sequential uptake of (14C) deoxyglucose in brain after embolic stroke

Summary An i.v. bolus of (¹⁴C) deoxyglucose was injected into 4 groups of rats which simultaneously were embolized through the internal carotid artery. 15 and 30 min post embolization there was a massive decrease in (¹⁴C) deoxyglucose uptake in both deep and cortical structures. At 4 h a small zone of increased (¹⁴C) deoxyglucose uptake persisted around each embolized microsphere.     

Vanadium biochemistry: The unknown role of vanadium-containing cells in ascidians (sea squirts)

Summary This article reviews several new developments in vanadium biochemistry, as elucidated from studies of ascidians. A hypothesis correlating ascidian blood cell function to anaerobiosis, via two prominent redox constituents, namely vanadium(III) and the tunichromes, a family of metal ion complexing/reducing hydroquinonoid peptides, is presented.