Spatially Resolved Observation of Supercurrents Across Grain Boundaries in YBaCuO Films

Spatially resolved resistivity measurements of current transport across individual grain boundaries have been made on superconducting YBa(2)Cu(3)O(7). These experiments were done by low-temperature scanning electron microscopy with a resolution of 1 to 2 micrometers, and they show directly the limitation of the critical current density caused by grain boundaries in YBa(2)Cu(3)O(7). Furthermore, complex spatial patterns of the current transport across grain boundaries were observed. These patterns reflect self-excited resonances of the grain boundaries and are closely correlated to the unexplained "sub-gap structure" in the current-voltage characteristics of polycrystalline YBa(2)Cu(3)O(7).     

A stem cell molecular signature

Mechanisms regulating self-renewal and cell fate decisions in mammalian stem cells are poorly understood. We determined global gene expression profiles for mouse and human hematopoietic stem cells and other stages of the hematopoietic hierarchy. Murine and human hematopoietic stem cells share a number of expressed gene products, which define key conserved regulatory pathways in this developmental system. Moreover, in the mouse, a portion of the genetic program of hematopoietic stem cells is shared with embryonic and neural stem cells. This overlapping set of gene products represents a molecular signature of stem cells.     

Induced pluripotent stem cells generated from patients with ALS can be differentiated into motor neurons

The generation of pluripotent stem cells from an individual patient would enable the large-scale production of the cell types affected by that patient's disease. These cells could in turn be used for disease modeling, drug discovery, and eventually autologous cell replacement therapies. Although recent studies have demonstrated the reprogramming of human fibroblasts to a pluripotent state, it remains unclear whether these induced pluripotent stem (iPS) cells can be produced directly from elderly patients with chronic disease. We have generated iPS cells from an 82-year-old woman diagnosed with a familial form of amyotrophic lateral sclerosis (ALS). These patient-specific iPS cells possess properties of embryonic stem cells and were successfully directed to differentiate into motor neurons, the cell type destroyed in ALS.     

Physical,compositional and sensory differences in nuts among pistachio (Pistachia vera L.) varieties

Differences in some physical, compositional and sensory characteristics among eight varieties of pistachio nuts (Aegina, Pontikis, Bronte, Cerasola, Joley, Kerman, Mumtaz and Sirora) from different origins were studied. The evaluated varieties were cultivated under the same field conditions and the dried nuts were utilised. The percentage of split nuts ranged from 93.8% (Sirora) to 80.2% (Aegina), the 10-nut weight from 15.23 g (Kerman) to 9.7 g (Cerasola), the kernel/nut percentage from 57.24% (w/w) (Pontikis) to 47.08% (w/w) (Kerman) and the ratio of length/width of nut from 1.81 (Aegina and Joley) to 1.56 (Mumtaz). Colour measurements showed the highest shell L* (80.26) for Kerman, the lowest shell h° (81.19) for Mumtaz, the lowest kernel membrane h° (24.43) for Cerasola, and the highest h° (107.23) on the inner kernel of Aegina. Crude protein content varied between 21.87 (Cerasola) and 18.99% d.w. (Joley), and the fat between 57.62 (Joley) and 49.79% d.w. (Cerasola). Among the major fatty acids in kernel oil, oleic ranged from 67.86% in Cerasola to 51.6% in Kerman, linoleic from 27.03% in Kerman to 11.56% in Pontikis and palmitic from 10.24% in Kerman to 8.54% in Cerasola. Linolenic acid was highest in Kerman (0.5%). Myristic, palmitoleic, stearic, vaccenic, arachidic and gondoic acids were also found in all samples. Negative and significant linear correlations were found between oleic and linoleic, and between mono- and poly-unsaturated fatty acids. Most of the physical and compositional characteristics measured were affected significantly by variety. Panelists preferred nuts of big size with a naturally yellowish shell colour. Visual differences in kernels were not significant, whereas Kerman, Sirora and Cerasola gained the panelists’ overall flavour preference among the varieties evaluated.     

Germplasm diversity and genetic relationships among walnut (Juglans regia L.) cultivars and Greek local selections revealed by Inter-Simple Sequence Repeat (ISSR) markers

Inter-Simple Sequence Repeat (ISSR) markers were used for the assessment of genetic diversity among walnut (Juglans regia L.) selections from Greek native populations in comparison to internationally cultivated walnut genotypes. Similarity coefficient values from 0.13 to 0.93 (with an average of 0.48) were found among the 56 accessions examined, which indicated the presence of a high degree of genetic variability. Most international cultivars were grouped together while most Greek native populations could not be placed into a distinct group. The Greek native population genotypes were found more diverse than the international cultivars. The mean similarity coefficient values for the former and latter were 0.44 and 0.56, respectively. In the cultivar group, two subgroups were distinguished; one consisted of genotypes involving ‘Payne’ and the other ‘Franquette’ in their pedigrees. Some cultivars and populations could not be grouped according to their pedigrees or collection area. Analysis of molecular variance (AMOVA) revealed that a larger part of the genetic variation exists among Greek walnut populations within a collection region (89%) than among the regions (11%). The pairwise regional PhiPT values indicated that the most geographically distant regions are the most genetically differentiated. The high variability existing in the Greek germplasm in combination with their valuable agro-morphological traits suggested that it would be beneficial to utilize this native germplasm pool in walnut breeding programs and germplasm management activities to maximize genetic diversity in cultivated walnut.