Electron diffraction of the metallic elements in the pineal organ of a freshwater fish, Mystus vittatus (Bloch.)

By electron diffraction pattern the presence of metallic elements, particularly chromium-nickel, chromium phosphide, copper, aluminum-copper and zinc has been shown in the pineal organ of a freshwater teleost, M. vittatus. It is likely that their occurrence within the pineal is due to binding with the neurosecretory material fractions/ligands.     

Histochemical localization of acetylcholinesterase in the glycogen body (sinus rhomboidalis) of common brown dove,Streptopelia senegalensis and house sparrow,Passer domesticus

Summary Acetylcholinesterase (AChE) activity was studied in the glycogen bodies of the spinal cords of 2 birds namelyStreptopelia senegalensis andPasser domesticus. A possible functional significance of AChE in the light of relative enzymatic localization especially in Hoffmann-Kolliker nuclei (motor cell groups), substantia gelatinosa and other regions of gray matter of 2 avian glycogen bodies has been discussed.     

Relation of HTLV-4 to simian and human immunodeficiency-associated viruses

Human immunodeficiency virus type 1 (HIV-1) is the aetiologic agent of AIDS (acquired immune deficiency syndrome) in most countries and probably originated in Central Africa like the AIDS epidemic itself. Evidence for a second major group of human immunodeficiency-associated retroviruses came from a report that West African human populations like wild-caught African green monkeys had serum antibodies that reacted more strongly with a simian immunodeficiency virus (STLV-3Mac) (ref.6) than with HIV-1. Novel T-lymphotropic retroviruses were reported to have been isolated from healthy Senegalese West Africans (HTLV-4) (ref. 4) and from African green monkeys (STLV-3AGM) (ref. 7), and a different retrovirus (HIV-2) was identified in other West African AIDS patients. Genomic analysis of HIV-2 clearly distinguished it from STLV-3 (ref. 9), but restriction enzyme site-mapping of three different HTLV-4 isolates and six different STLV-3AGM isolates showed them to be essentially indistinguishable. In this report we clone, restriction map, and partially sequence three isolates of HTLV-4 (PK82, PK289, PK190) (ref. 4). We find that these viruses differ in nucleotide sequence from each other and from three isolates of STLV-3AGM (K78, K6W, K1) (ref. 7) by 1% or less. We also report the isolation of a T-lymphotropic retrovirus from the peripheral blood of a healthy Senegalese woman which hybridizes preferentially to HIV-2 specific DNA probes. We conclude that HTLV-4 (ref. 4) and STLV-3AGM (ref. 7) are not independent virus isolates and that HIV-2 is present in Senegal as it is in other West African countries.     

A possible role of guanine-deaminase inhibitor

Zusammenfassung Diskussion über die Frage der Ätiologic der Xanthinurie.     

MD simulation of asymmetric nucleation and motion of 〈011〉 superdislocations in TiAI

The nucleation and propagation of （011] su- perdislocations in intermetallic TiA1 were investigated using molecular dynamics simulations and static energetics calculation, as part of our systematic effort to understand the twining and dislocation behavior of alloys based on y-TiAl. It was found that compared to ordinary dislocations in disordered crystals, superdislocations in ordered TiA1 lattice behave differently when sheared in the two opposite senses along [01-1] direction. This difference is due to the lower Llo lattice symmetry compared with the face-cen- tered cubic （fcc） lattice that it based on, with different yield stress and strain, and dislocation core dissociation and motion. Superdislocations nucleated in the form of loops dissociated in a planar manner into four Shockley partials separated by three kinds of faults： superlattice intrinsic stacking fault （SISF）, anti-phase domain boundary （APB） and complex stacking fault （CSF）, with partial separations depending on the sense of shearing and dislocation char- acter. During loop expansion, the dislocation core changes both in width and dissociation manner depending on the character of the segment in the loop. The core contains four partials close to edge orientation, gradually changing to three fold near 60°, and finally into twofold dissociation around 30° character. Superdislocations may have multiple critical resolved shear stresses （CRSS） for motion depending on dissociation and shearing sense even for the same slip system, with lower critical stress for the motion when SISF is in leading position.     

A brief survey of computerized expert systems for crop protection being used in India

In the recent years, a plethora of computerized expert systems has been developed for various sectors of agriculture in India. The availability of low-cost computers, agricultural knowledge and information technology professionals are the principal reasons for the development of so many agricultural expert systems. Among all agricultural expert systems, the expert systems for crop protection need special mention. These expert systems are meant to be used by farmers and other persons without much experience of using computers. Hence, special care must be taken while developing them. The current paper develops a taxonomy for the expert systems for crop protection and briefly discusses four such expert systems for crop protection being used in India.