Graphene Plasmonic Crystal: Two-Dimensional Gate-Controlled Chemical Potential for Creation of Photonic Bandgap

Plasmonics - A new design of graphene-based plasmonic waveguide is presented and its transmission properties are studied. The transmission channel is such designed that the chemical potential of...     

Interference of tolerance to human gamma globulin by synthetic polynucleotides.

A complex of polyadenylic-polyuridylic acids effectively inhibits the in vivo production of immunologic tolerance to human gamma globulin in mice. Moreover, this effect can be obtained only when the polynucleotide complex is given within 4 hr after antigen administration.Reconstitution of irradiated mice with combinations of T and B cells originating from tolerant or previously untreated mice demonstrates that poly A:U is responsible for the adjuvant effect observed. Poly A:U exerts its adjuvant effect primarily upon T cells, while B cells remain essentially uninfluenced by the polynucleotides.     

Fetal nuchal translucency: ultrasound screening for chromosomal defects in first trimester of pregnancy.

OBJECTIVE--To examine the significance of fetal nuchal translucency at 10-14 weeks'' gestation in the prediction of abnormal fetal karyotype. DESIGN--Prospective screening study. SETTING--The Harris Birthright Research Centre for Fetal Medicine, King''s College Hospital, London. SUBJECTS--827 fetuses undergoing first trimester karyotyping by amniocentesis or chorionic villus sampling. MAIN OUTCOME MEASURE--Incidence of chromosomal defects. RESULTS--The incidence of chromosomal defects was 3% (28 of 827 cases). In the 51 (6%) fetuses with nuchal translucency 3-8 mm thick the incidence of chromosomal defects was 35% (18 cases). In contrast, only 10 of the remaining 776 (1%) fetuses were chromosomally abnormal. CONCLUSION--Fetal nuchal translucency > or = 3 mm is a useful first trimester marker for fetal chromosomal abnormalities.     

Endophytic Penicillium species secretes mycophenolic acid that inhibits the growth of phytopathogenic fungi

The worldwide demand for reduced and restricted use of pesticides in agriculture due to serious environmental effects, health risks and the development of pathogen resistance calls for the discovery of new bioactive compounds. In the medical field, antibiotic-resistant microorganisms have become a major threat to man, increasing mortality. Endophytes are endosymbiotic microorganisms that inhabit plant tissues without causing any visible damage to their host. Many endophytes secrete secondary metabolites with biological activity against a broad range of pathogens, making them potential candidates for novel drugs and alternative pesticides of natural origin. We isolated endophytes from wild plants in Israel, focusing on endophytes that secrete secondary metabolites with biological activity. We isolated 302 different endophytes from 30 different wild plants; 70 of them exhibited biological activity against phytopathogens. One biologically active fungal endophyte from the genus Penicillium, isolated from a squill (Urginea maritima) leaf, was further examined. Chloroform-based extraction of its growth medium was similarly active against phytopathogens. High-performance liquid chromatography separation followed by gas chromatography/mass spectrometry analysis revealed a single compound—mycophenolic acid—as the main contributor to the biological activity of the organic extract.     

High yellow pigments production by root culture of <Emphasis Type="Italic">Carthamus tinctorius</Emphasis> and its release in medium under gas oil treatment

In this study, the ability of safflower-isolated root cultures to produce yellow pigments was tested. Initially, the growth of isolated roots in static liquid medium was evaluated with different volumes of culture medium. A volume of 6 ml of medium per flask of 250 ml gave the best growth performance and, in this condition of culture, production of pigments from isolated roots treated or not by light has been determined by spectrophotometry (321 and 400 nm). Under these conditions, the production of yellow pigments amounted to 13.18 mg g⁻¹ fresh weight and the light stimulated the synthesis of these pigments by isolated roots. Total yellow pigments of 24.12, 38.91 and 46.38 mg g⁻¹ fresh weight was produced by the roots treated with 9, 13.5 and 18% (v/v) gas oil, respectively, representing high values of production. The pigments were released in large quantities in the medium. The increased synthesis of pigments as a result of gas oil treatment was accompanied by a reduction of the peroxidase activity of roots. Given the high production of yellow pigments, systems of isolated root culture could be considered for the study of a larger scale production of safflower pigments widely used for various industrial purposes.