EXPLICIT SOLUTION FOR G-BAND MODE FREQUENCY OF SINGLE-WALLED CARBON NANOTUBES

G-band mode is one of the most important Raman modes of single-walled carbon nanotubes （SWCNTs）. The vibrational frequency of the mode can be used to characterize SWC- NTs. However, analytical expression that can link the frequency to the geometrical parameters of a SWCNT is to date not reported. Based on a molecular mechanics model, the analytical solution is obtained for G-band mode frequency of SWCNTs. The result calculated from the present solutions is in good agreement with the existing experimental and numerical data.

Chromosome G-banding in plants by inducing with trypsin and urea

Clear G-bands were revealed by applying the TUG method on chromosomes of 5 species of higher plants (Lilium davdii, Viciafaba, Hordeum vulgare, Ginkgo biloba and Triticum monococcam). Some details of the TUG method which consisted of treating chromosomes with both trypsin and urea were also studied. The mechanisms that might account for the presence of G-bands in plants were discussed.

Isodicentric Ychromosome: Case Study

Isodicentric chromosomes are a frequently appearing abnormality in the human Y chromosome. Making predictions regarding the phenotypic outcomes of a variety of duplications/deletions in the dicentric Y chromosome generally depends on the breakpoint location and also the level of mosaicism (45, X cell lines);in certain instances, these may not be detected and result in variations running between male, abnormal female, or ambiguity in individual genitalia. A referral was received from a urology clinic concerning two patients, one aged 34 and one aged 35, with a request to investigate reasons for infertility: G-banded karyotyping and fluorescence in situ hybridization (FISH) revealed the presence of an isodicentric Y chromosome.

High Resolution G-banding and Idiogram on Pachytene Bivalents of Rice Field Eels(Monopterus albus Zuiew)

Well spread pachytene bivalents and high resolution G-handing patterns have been obtainedby using the prolonged hypotonic treatment combined with the trypsin-hot salt banding technique in the sper-maries of rice field eels(Monopterus albus Zuiew).Each bivalent has been idendified and a total of 310—450 bands on 12 bivalents observed.This might bethe largest number of multiple bands obtained from fish chromosomes so far published.An idiogram of 372G-bands has been set up and detailed descriptions of the landmark systems and the band positions have beengiven.

HIGH RESOLUTION G-BANDING IN PLANT CHROMOSOMES INDUCED AT HIGH TEMPERATURE

In the past few years, clear and abundant G-bands in more than ten plants have been successfully observed by use of animal and human G-banding procedures, which mainly include trypsin, ASG, AMD, urea, SDS, NaOH, NaHCO3 and Utakoji methods etc. However, all G-banding production methods have direct relations with the chemical factors. Although there is usually heat treatment （about 60℃） prior to the G-banding procedure in animal and human chromosomes, G-banding patterns have not yet been reported only by specif-

Sex chromosomes behavior and G-banding treatment of male meiosis in nuptial gift-giving spiders of the family Trechaleidae

Preliminary genetic studies in Trechaleidae spider family show high variation in sex chromosomes and high heterocigocity,suggesting high chromatin plasticity.The trechaleids Paratrechalea ornata,Trechalea bucculenta and Trechaleoides biocellata are present in Uruguay.Males offering nuptial gifts during courtship have been reported in P.ornata and T.bucculenta but not in T.biocellata.Nuptial gifts are an inherited trait probably highly affected by environmental factors,which play an important role in gene expression.We hypothesize that this trait could be associated with tissue-specific genes existing in G-bands.We investigate the male meiosis in these 3 species,their sex chromosome system and the effects of G-banding on their chromosomes,and elucidate genetic differences among them.Meiotic stages of the 3 species were submitted to Giemsa-staining and G-banding treatments.We observed a haploid number of n=11 in P.ornata and n=13 in both T.bucculenta and T.biocellata.Males from the 3 species presented an X_(1)X_(2)0 sex chromosome system,which is suggested as ancestral in Araneae.In P.ornata and T.bucculenta,both sex chromosomes were together and aligned in parallel until the segregation during anaphase I.In contrast to these species,sex chromosomes of T.biocellata usually remained distant from each other until diakinesis when they were observed associated in parallel disposition.Interstitial G-bands were similar in P.ornata and T.bucculenta,and they both differed from those in T.biocellata.The special behavior of sex chromosomes in T.biocellata as well as the different G-banding pattern of this species suggests the existence of novel modifications in this species.

Direct Observation of the Strong Interaction Between Carbon Nanotubes and Quartz Substrate

We present a chemical vapor deposition(CVD)method for the growth of uniform single-walled carbon nanotube(SWNT)arrays on a stable temperature(ST)-cut single crystal quartz substrate using a mixture of methanol and ethanol as carbon source.It is found that introducing methanol during the growth can improve the density and the length of the well-aligned SWNTs in the arrays as well as increase the SWNT/quartz interaction.Obvious“up-shifts”of G-band frequencies in the Raman spectra have been found for the aligned SWNTs.A well-designed control experiment shows that the G-band“up-shifts”originate from the strong interaction between SWNTs and the quartz substrate.It is believed that exploring this interaction will help to elucidate the growth mechanism;ultimately,this will help realize the promise of controlling the chirality of SWNTs.