Evidence for strain-induced local conductance modulations in single-layer graphene on SiO2.

Graphene has emerged as an electronic material that is promising for device applications and for studying two-dimensional electron gases with relativistic dispersion near two Dirac points. Nonetheless, deviations from Dirac-like spectroscopy have been widely reported with varying interpretations. Here we show evidence for strain-induced spatial modulations in the local conductance of single-layer graphene on SiO(2) substrates from scanning tunneling microscopic (STM) studies. We find that strained graphene exhibits parabolic, U-shaped conductance vs bias voltage spectra rather than the V-shaped spectra expected for Dirac fermions, whereas V-shaped spectra are recovered in regions of relaxed graphene. Strain maps derived from the STM studies further reveal direct correlation with the local tunneling conductance. These results are attributed to a strain-induced frequency increase in the out-of-plane phonon mode that mediates the low-energy inelastic charge tunneling into graphene.

Uterine artery embolization: a minimally invasive technique for the treatment of uterine fibroids.

Uterine artery embolization (UAE) as a primary therapy for symptomatic fibroids was first used in France in 1991. Currently, there are at least 250 centers in the United States, as well as centers in Canada and England, with experience in this technique. Initial published results worldwide indicate that after UAE, uterine fibroids shrink at least 50% in volume on average and symptoms of refractory vaginal bleeding and chronic pelvic pain are controlled in approximately 85% of patients. Major complications are rare. Overall, this technique is minimally invasive, preserves the uterus, and requires a shorter hospitalization than hysterectomy or myomectomy.

Immunocytological diagnosis of primary cerebral non-Hodgkin's lymphoma.

Four men with primary cerebral non-Hodgkin's lymphoma diagnosed by immunocytological analysis of cerebrospinal fluid (CSF) presented with cranial nerve palsies. All had CSF lymphocytoses and low CSF glucose. The cell phenotypes were two T cell tumours, one B cell, and one null. A review of 13 previously recorded cases of immunocytologically diagnosed CNS non-Hodgkin's lymphoma showed that there were 10 B cell, two T cell, and one null tumour. Overall (17 cases) the cell phenotype distribution was 65% B cell, 24% T cell, and 11% null. High CSF lymphocyte counts were found in 94%, proteinosis in 85%, and low CSF glucose in 87%. In contrast to the B cell tumours, all of the T cell tumours were diagnosed by CSF cytology before being visualised radiologically. It is suggested that all CSF lymphocytes (greater than 5 x 10(6)/ml) should be immunohistochemically typed to permit earlier diagnosis of CNS non-Hodgkin's lymphoma.

Effect of haemolysate preparation on measurement of red cell folate by a radioisotopic method.

The effects of varying the method of preparation of haemolysates on the measurement of red cell folate concentration were investigated using the Simultrac kit. The concentration of ascorbic acid did not have any significant effect on the assayed concentrations of folate, but lower concentrations were obtained when the incubation time was increased. Folate was stable for 14 days in cells when they were stored at 4 degrees C and for seven days at -25 degrees C, but instability was increased by storage in ascorbic acid, by the use of stored (4 degrees C) ascorbic acid, and by preparing the haemolysates by freeze-thaw cycling. It is recommended that haemolysates should be diluted in fresh ascorbic acid, at a concentration of 10 g/l, incubated for 60 minutes in the dark and stored at -20 degrees/25 degrees C before being assayed.

Automated leucocyte differential counts in chronic lymphocytic and hairy-cell leukaemias: a comparison of the Hemalog D, H6000 and Coulter S Plus IV.

The automated peripheral blood differential counts produced by the Hemalog D, H6000 and Coulter S Plus IV were analysed and compared in 30 cases of chronic lymphocytic leukaemia (CLL) and 12 cases of hairy-cell leukaemia. All three machines were reliable in identifying CLL and HCL as a 'lymphocytosis' and in estimating neutrophil numbers in the disease. The Hemalog D and H6000 produced accurate monocyte counts in the two diseases, but the Coulter S Plus IV was unreliable in this regard since large lymphoid cells were identified as monocytes. The Haemalog D and H6000 were comparable in consistently identifying modestly raised large unstained cells (LUCs) in CLL. The Hemalog D, but not the H6000, was able to distinguish HCL from CLL on the basis of markedly raised LUCs.

Certain myeloid cells possess receptors for interleukin-2.

A proportion of blasts from five of 10 cases of AML expressed receptors for IL-2 (IL-2R) when tested directly ex-vivo with monoclonal antibodies against the receptor. After in-vitro stimulation with various agents including TPA, gamma interferon and colony stimulating factor, the purified blast cells of all cases of AML tested (10 of 10) showed high levels (50-90% cells positive) of IL-2R expression. Granulocytic cells from the promyelocyte stage onwards lacked IL-2R both before and after in-vitro stimulation. In contrast, leukaemic promonocytes and normal peripheral monocytes expressed IL-2R both before and after stimulation. The receptors were detected with two different monoclonal antibodies (anti-Tac and 4H3--both IgG 2a antibodies) by indirect rosetting. In selected experiments, results were confirmed by fluorescence microscopy and by the APAAP technique. Normal monocytes possessed only small amounts of IL-2R since positivity was clearly detectable only by the indirect rosette assay. Irrelevant IgG 2a first-layer and second-layer-only controls were always negative. The endogenous nature of the IL-2 receptors was demonstrated by re-expression after capping and shedding. That the antigens detected were true IL-2R was confirmed by the fact that monoclonal antibody staining was blocked by recombinant IL-2. The restricted expression of IL-2R on early granulocytic and on monocytoid cells raises the possibility that IL-2 is important in the proliferation of these cell types.

A rise in the percentage of large unstained cells in the peripheral blood determined by the Hemalog D90 automated differential counter is a feature of impending myeloid engraftment following bone marrow transplantation.

The early phase of bone marrow regeneration has been monitored by automated differential counts on the peripheral blood using a Hemalog D90, following 107 transplant procedures. An elevated percentage of large unstained cells (LUCs) was detected in over 98% of cases and in 72% of cases the rise in percentage LUCs preceded the rise of the total leucocyte count into the detectable range on a Coulter counter (greater than 0.3 X 10(9)/1) by an average of 4 days. These LUCs are shown to be CD8 + T lymphocytes. The ability to detect the earliest signs of regeneration is particularly useful when regeneration is delayed and repeat marrow infusion is considered.

Automated leucocyte differential counts in acute leukaemia: a comparison of the Hemalog D, H6000 and Coulter S-plus IV.

The automated peripheral blood differential counts produced by the Hemalog D, H6000 and Coulter S-plus IV were analysed in 32 cases of acute leukaemia (22 AML (acute myeloblastic leukaemia); 10 ALL (acute lymphoblastic leukaemia], all with greater than 30% circulating blast cells. All three machines were highly effective in recognizing the presence of an abnormality. With the Hemalog D and H6000, the presence of increased LUC and HPX cells, together with an LPX alarm, was suggestive of acute leukaemia. With the Coulter S-plus IV, multiple alarms indicated the need for further investigation but, since alarms occur in many other situations, their presence was not necessarily suggestive of acute leukaemia. All the machines were of value in distinguishing AML from ALL since 'lymphocytes' were predominant in all cases of ALL and 'neutrophils' the majority cell type in most patients with AML. However, the presence in a minority of cases of AML of large numbers of micromyeloblasts recognized as 'lymphocytes' limited the discriminating power of all three machines. The Hemalog D allowed some definition of subtypes of AML, but the H6000 and Coulter S-plus IV were of no value in this regard.

Bone marrow macrophages and megakaryocytes express common acute lymphoblastic leukaemia antigen.

Common acute lymphoblastic leukaemia antigen (CALLA) was demonstrated on a proportion of bone marrow macrophages and megakaryocytes. CALLA was detected by two monoclonal antibodies (J5 & BA3) in a three-layer immunoalkaline phosphatase system applied to routine air-dried bone marrow smears. The J5 staining was confirmed by an indirect immunofluorescent method and the CALLA was shown to be at the surface of the macrophages and megakaryocytes by an indirect immunogold technique. The findings are discussed in relation to the known tissue distribution of CALLA and to the clinical use of anti-CALLA antibodies for bone marrow purging.