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Nanobubbles formed in monolayers of transition metal dichalcogenides (TMDCs) on top of a substrate feature localized potentials in which electrons can be captured. We show that the captured electronic density can exhibit a nontrivial spatiotemporal dynamics, whose movements can be mapped to states in a two-level system illustrated as points of an electronic Poincaré sphere. These states can be fully controlled, i.e, initialized and switched, by multiple electronic wave packets. Our results could be the foundation for novel implementations of quantum circuits.

The interplay of optics, dynamics, and transport is crucial for the design of novel optoelectronic devices, such as photodetectors and solar cells. In this context, transition-metal dichalcogenides (TMDs) have received much attention. Here, strongly bound excitons dominate optical excitation, carrier dynamics, and diffusion processes. While the first two have been intensively studied, there is a lack of fundamental understanding of nonequilibrium phenomena associated with exciton transport that is of central importance (e.g., for high-efficiency light harvesting). In this work, we provide microscopic insights into the interplay of exciton propagation and many-particle interactions in TMDs. On the basis of a fully quantum mechanical approach and in excellent agreement with photoluminescence measurements, we show that Auger recombination and emission of hot phonons act as a heating mechanism giving rise to strong spatial gradients in excitonic temperature. The resulting thermal drift leads to an unconventional exciton diffusion characterized by spatial exciton halos.

The usefulness of adult stem cells in research and therapeutic applications highly relies on their genomic integrity and stability. Many laboratories including ours have addressed this concern using methods such as karyotyping, Qbanding, fluorescent in situ hybridization, array CGH, flow cytometry and Pap test to evaluate number and structure of chromosomes and cellular phenotype. This review attempts to summarize the findings reported so far for the studies on chromosomal aberrations in adult stem cells and warrant to perform certain basic tests before transplantation to avoid any adverse reactions, which will thus aid in better therapeutic output after cellular transplantation in the treatment of various diseases.

•A novel Simulated Annealing approach that makes use of a portfolio of different neighborhoods.•We undertake the two versions of the problem and the corresponding benchmark instances.•We outperform all previous results on most instances for one version of the problem, and we are at the same level of the best ones for the second version.•We designed a new robust file format for instances and solutions, and a data repository for validating and maintaining the available solutions.

Nucleophosmin (NPM)exon-12 mutations occur in 50% to 60% of adult acute myeloid leukemia (AML) with normal karyotype and are predictors of favorable prognosis. We evaluated bone marrow or peripheral blood samples from 450 adult patients with AML of the GIMEMA (Gruppo Italiano Malattie Ematologiche Maligne dell'Adulto)/AML12 EORTC (European Organization for Research and Treatment of Cancer) trial to (1) search for new exon-12 NPMmutations; (2) determine whether NPM immunostaining on paraffin-embedded biopsies predicts NPMmutations; and (3) investigate altered nucleocytoplasmic NPM traffic in primary AML cells. Fourteen NPMmutations, including 8 new variants, were identified. All 200 AML cases expressing cytoplasmic NPM (NPMc+AML) carried NPMmutations. None of the 250 cases with nucleus-restricted NPM (NPMc–AML) was mutated. At the C-terminus, NPM leukemic mutants carried mutations of only tryptophan 290 or of both tryptophans 288 and 290 and a new nuclear export signal (NES) motif, which appear to underlie their nuclear export. The specific Crm1/exportin-1 inhibitor leptomycin-B relocated NPM mutants from cytoplasm to nucleus of primary NPMc+AML cells, demonstrating that nuclear export is NES dependent. NPM mutants bound and recruited wild-type NPM into leukemic cell cytoplasm. Because alterations at C-terminus of leukemic NPM mutants are similar, immunohistochemistry detects all exon-12 NPMmutations and is a valuable, inexpensive tool in the diagnostic-prognostic work-up of patients with AML with normal karyotype.

Nucleophosmin (NPM) exon-12 mutations occur in 50% to 60% of adult acute myeloid leukemia (AML) with normal karyotype and are predictors of favorable prognosis. We evaluated bone marrow or peripheral blood samples from 450 adult patients with AML of the GIMEMA (Gruppo Italiano Malattie Ematologiche Maligne dell'Adulto)/AML12 EORTC (European Organization for Research and Treatment of Cancer) trial to (1) search for new exon-12 NPM mutations; (2) determine whether NPM immunostaining on paraffin-embedded biopsies predicts NPM mutations; and (3) investigate altered nucleocytoplasmic NPM traffic in primary AML cells. Fourteen NPM mutations, including 8 new variants, were identified. All 200 AML cases expressing cytoplasmic NPM (NPMc+ AML) carried NPM mutations. None of the 250 cases with nucleus-restricted NPM (NPMc– AML) was mutated. At the C-terminus, NPM leukemic mutants carried mutations of only tryptophan 290 or of both tryptophans 288 and 290 and a new nuclear export signal (NES) motif, which appear to underlie their nuclear export. The specific Crm1/exportin-1 inhibitor leptomycin-B relocated NPM mutants from cytoplasm to nucleus of primary NPMc+ AML cells, demonstrating that nuclear export is NES dependent. NPM mutants bound and recruited wild-type NPM into leukemic cell cytoplasm. Because alterations at C-terminus of leukemic NPM mutants are similar, immunohistochemistry detects all exon-12 NPM mutations and is a valuable, inexpensive tool in the diagnostic-prognostic work-up of patients with AML with normal karyotype.

We recently identified aberrant cytoplasmic expression of nucleophosmin (NPM) as the immunohistochemical marker of a large subgroup of acute myeloid leukemia (AML) (about one-third of adult AML) that is characterized by normal karyotype and mutations occurring at the exon-12 of the NPMgene. In this paper, we have elucidated the molecular mechanism underlying the abnormal cytoplasmic localization of NPM. All 29 AML-associated mutated NPMalleles so far identified encode abnormal proteins which have acquired at the C-terminus a nuclear export signal (NES) motif and lost both tryptophan residues 288 and 290 (or only the residue 290) which determine nucleolar localization. We show for the first time that both alterations are crucial for NPM mutant export from nucleus to cytoplasm. In fact, the cytoplasmic accumulation of NPM is blocked by leptomycin-B and ratjadones, specific exportin-1/Crm1-inhibitors, and by reinsertion of tryptophan residues 288 and 290, which respectively relocate NPM mutants in the nucleoplasm and nucleoli. NPM leukemic mutants in turn recruit the wild-type NPM from nucleoli to nucleoplasm and cytoplasm. These findings indicate that potential therapeutic strategies aimed to retarget NPM to its physiological sites will have to overcome 2 obstacles, the new NES motif and the mutated tryptophan(s) at the NPM mutant C-terminus.

We recently identified aberrant cytoplasmic expression of nucleophosmin (NPM) as the immunohistochemical marker of a large subgroup of acute myeloid leukemia (AML) (about one-third of adult AML) that is characterized by normal karyotype and mutations occurring at the exon-12 of the NPM gene. In this paper, we have elucidated the molecular mechanism underlying the abnormal cytoplasmic localization of NPM. All 29 AML-associated mutated NPM alleles so far identified encode abnormal proteins which have acquired at the C-terminus a nuclear export signal (NES) motif and lost both tryptophan residues 288 and 290 (or only the residue 290) which determine nucleolar localization. We show for the first time that both alterations are crucial for NPM mutant export from nucleus to cytoplasm. In fact, the cytoplasmic accumulation of NPM is blocked by leptomycin-B and ratjadones, specific exportin-1/Crm1-inhibitors, and by reinsertion of tryptophan residues 288 and 290, which respectively relocate NPM mutants in the nucleoplasm and nucleoli. NPM leukemic mutants in turn recruit the wild-type NPM from nucleoli to nucleoplasm and cytoplasm. These findings indicate that potential therapeutic strategies aimed to retarget NPM to its physiological sites will have to overcome 2 obstacles, the new NES motif and the mutated tryptophan(s) at the NPM mutant C-terminus.

NPM1 gene mutations are the most frequent genetic lesion in the 60% of adult acute myeloid leukemias (AMLs) with normal karyotype and no evidence of typical fusion genes (BCR/ABL1, PML/RARA, AML1/ETO, CBFB/MYH11, DEK/CAN). Using direct sequencing we previously identified six different heterozygous mutants within exon 12 encoding the nucleophosmin C-terminus. Because of these mutations the shuttling protein nucleophosmin is aberrantly delocalized in the cytoplasm of leukemic cells (NPMc+). Here, we designed and tested a denaturing high-performance liquid chromatography (DHPLC) assay to detect NPM1 mutated variants. To assess specificity, sensitivity, reliability, and reproducibility, we analyzed DNA from 120 primary adult AMLs and compared DHPLC results with immunohistochemistry and sequencing. All electropherogram profiles in the 26 NPMc+ leukemias were different from the wild type, indicating 100% sensitivity. Sequencing categorized mutations A, B, and D, and all mutation A cases gave identical elution profiles. The other mutations showed typical chro-matograms, with mutations B and D differing for one nucleotide. Elution profiles and sequencing also identified four new variants. Our results suggest that DHPLC detects NPM1mutations as well as direct sequencing and immunohistochemistry, providing a helpful approach in the diagnosis of NPMc+ AML.

Fusion between the NUP98 and NSD3genes in a patient with acute myeloid leukemia associated with t(8;11)(p11.2;p15), is reported for the first time. The t(8;11)(p11.2;p15) was identified by classical cytogenetics. Fluorescence in situ hybridization (FISH) analysis revealed a split signal with a mix of BAC 118H17 and 290A12, indicating the translocation disrupted NUP98. FISH restriction at 8p11-12 showed a split of BAC 350N15. Molecular investigations into candidate genes in this BAC showed the NUP98 fusion partner at 8p11.2 was the NSD3 gene. To date the NSD3 gene has never been implicated in hematologic malignancies.

Fusion between the NUP98and NSD3genes in a patient with acute myeloid leukemia associated with t(8;11)(p11.2;p15), is reported for the first time. The t(8;11)(p11.2;p15) was identified by classical cytogenetics. Fluorescence in situ hybridization (FISH) analysis revealed a split signal with a mix of BAC 118H17 and 290A12, indicating the translocation disrupted NUP98. FISH restriction at 8p11-12 showed a split of BAC 350N15. Molecular investigations into candidate genes in this BAC showed the NUP98fusion partner at 8p11.2 was the NSD3gene. To date the NSD3gene has never been implicated in hematologic malignancies.

Solubilized A1 adenosine receptor (A1AR) was used to investigate the effect of several cations on agonist-binding characteristics and GTP hydrolysis. It was shown by Western blot with Gβ-M14 that this preparation contains both G proteins and receptor. The role of the receptor molecule is to facilitate the activation of G proteins as α-GTP complex, and GTP hydrolysis has important consequences for the basic deactivation mechanism. Divalent cations, such as Mn2+, Ca2+, and Mg2+, potentiated the agonist-specific binding: Mn2+had the highest apparent affinity with half-maximal effect at 50 μM. Binding assays, performed in the presence of 100 μM Mn2+, showed an increase in the apparent affinity of the binding sites, whereas, in the presence of 1 mM Mg2+, significant alteration of the apparent affinity, but not of the number of sites, was detected. Concentrations of 1 mM Mg2+and 100 μM Mn2+enhanced GTPase activity, whereas 5 mM Ca2+resulted in the increase ofVmaxvalues without significant alterations ofKm. In the presence of A1-specific agonists, Mn2+and Mg2+caused a decrease ofVmaxvalues and an increase of GTP affinity. Other cations, such as Co2+, Cd2+, Cu2+, and Zn2+, inhibited the binding capacity but caused almost no changes in GTP hydrolysis kinetics.

Most chromosomal translocations in myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML) involve oncogenes which are either up-regulated or form part of new chimeric genes. The t(2;11)(p21;q23) translocation has been cloned in 19 cases of MDS and AML. In addition to this, we have shown that this translocation is responsible for a strong up-regulation of miR-125b (6 to 90 fold). In vitroexperiments revealed that miR-125b was able to block monocytic and granulocytic differentiation of leukemic cells and primary CD34+ human blasts. Therefore, miR-125b up-regulation may represent a new mechanism of myeloid cell transformation and myeloid neoplasms carrying the t(2;11) translocation define a new clinico-pathological entity.

Most chromosomal translocations in myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML) involve oncogenes which are either up-regulated or form part of new chimeric genes. The t(2;11)(p21;q23) translocation has been cloned in 19 cases of MDS and AML. In addition to this, we have shown that this translocation is responsible for a strong up-regulation of miR-125b (6 to 90 fold). In vitro experiments revealed that miR-125b was able to block monocytic and granulocytic differentiation of leukemic cells and primary CD34+ human blasts. Therefore, miR-125b up-regulation may represent a new mechanism of myeloid cell transformation and myeloid neoplasms carrying the t(2;11) translocation define a new clinico-pathological entity.

We recently found that about one-third of adult AML (60% of all AML with normal karyotype) display aberrant cytoplasmic expression of nucleophosmin (NPM) which is due to mutations occurring at the exon-12 of NPM gene (Falini B, et al., Cytoplasmic nucleophosmin in acute myelogenous leukemia with a normal karyotype..N Engl J Med2005; 352: 254–266). Hereby, we clarify the molecular mechanism underlying cytoplasmic NPM accumulation that yet remained to be elucidated. AML-associated mutated NPM alleles encode abnormal NPM proteins (25 mutants so far identified) which have acquired at the C-terminus a nuclear export signal-(NES) motif and lost at least one of tryptophan residues 288 and 290 which determine nucleolar localization. Both alterations are crucial for mutant NPM export from nucleus to cytoplasm. In fact, the cytoplasmic NPM accumulation is blocked by leptomycin-B and ratjadones which are specific inhibitors of exportin-1/CRM1, and by re-insertion of tryptophan residues 288 and 290, which respectively relocate NPM mutants in the nucleoplasm and nucleoli. Thus, for cytoplasmic accumulation of NPM to occur, the NES motif and tryptophan mutations must act in concert. Possibly, when NPM mutans enter the nucleus by virtue of their nuclear localization signals (NLS), their capability to bind nucleoli must be hindered at least partially to become a CRM-1 target. Specific antibodies anti-NPM mutant proteins showed that the mutants localized exclusively in the cytoplasm and recruited in that site the wild-type NPM protein which is physiologically located in the nucleoli. These findings suggest that the NPM mutants may interfere with the functions of wild-type NPM and possibly contribute to leukemogenesis. Immunostaining of 393 AML cases using anti-NPM monoclonal antibodies predicted the presence of NPM exon-12 mutations in all 191 NPM-cytoplasmic positive cases. This finding is consistent with the fact that, despite genomic heterogeneity, all NPM mutants contain a NES motif which, in the presence of altered tryptophans, promotes their rapid export from the nucleus to the cytoplasm. The immunohistochemical test is diagnostically relevant since it can be used as simple first-step procedure in molecular-genetic characterization of AML and as a surrogate for mutational analysis in selected cases. These findings are also clinically relevant since cytoplasmic NPM/NPM mutations are predictors of good response to induction therapy and favourable prognosis in AML with a normal karyotype.

Normal cytogenetics in AML is a major drawback to detect minimal residual disease. We have identified heterozygous NPM1 mutations as the most frequent genetic lesion in AML with normal karyotype (NEJM2005:352,254). Mutations A, B and D, all characterized by tetranucleotide insertions, account for more than 90% of all mutations. NPM1 mutations are new important prognostic markers in AML with normal cytogenetics, being predictive of successful response to induction treatment (NEJM2005:352,254) and longer overall survival in cases without FLT3 mutations (Dohner K et al, and Schnittger S et al, Blood 2005, on line). Their clinical impact prompted us to develop a Real Time Quantitative PCR assay for the identification and monitoring of NPM1 mutants. Tests were set up using either cDNA (13 adult cases with mutation A and 1 with mutation B) or genomic DNA (gDNA) (7 pediatric and 8 adult patients). cDNA RQ-PCR . Forward primer was designed in exon 11, probe in exon 11/exon 12 junction (5′-FAM-3′-MGB) and reverse primers in exon 12. Samples were analyzed in ABI PRISM 7700 Sequence Detection System (Applied Biosystems). ABL1 gene was used as control. For the absolute quantitative assessment of NPM1 mutation A copies a standard curve with serial dilutions of a plasmid containing the target sequences was used. The highest reproducible sensitivity of this RQ-PCR assay was 10 molecules. The highest reproducible sensitivity of the relative quantification RQ-PCR assay for mutation A and B was 10−4. Thirteen AML NPM mutation A patients were monitored at diagnosis and over follow up. The number of mutated copies was high in all cases at diagnosis and significantly decreased after induction treatment in all cases with complete hematological remission. Only a slight decrease was observed in the case who did not reach remission. Patients with a complete hematological remission but MRD decrease <3log showed a higher risk of relapse. gDNA RQ-PCR . specific forward primers for six different mutations were designed using Primer Express software to anneal to the mutated region of NPM exon 12. Reverse primers were designed on NPM1 exon 12. The TaqMan core reagent kit (Applied Biosystems) was used for RQ-PCR. The albumin gene was used as control. A reproducible sensitivity of 10−4 was reached in all but one case. The mean Ct of undiluted DNA samples was 23.3 (range 22.1–24.8). The mean slope of the dilution curves was 3.6 (2.9–4.0). High correlation coefficients (0.99 in all but one) were obtained. Using both cDNA and gDNA we set up sensitive and reproducible systems to detect minimal residual disease in 60% of AML with normal karyotype and NPM gene mutations. While gDNA RQ-PCR has the advantage to be directly related to the number of residual leukemic cells, cDNA RQ-PCR can be easily applied in samples collected in the routine diagnostic testing for common translocations. Large prospective studies are necessary to clarify the clinical impact of NPM1-based MRD monitoring of AML with normal karyotype.

We recently found that about one-third of adult AML (60% of all AML with normal karyotype) display aberrant cytoplasmic expression of nucleophosmin (NPM) which is due to mutations occurring at the exon-12 of NPMgene (Falini B, et al., Cytoplasmic nucleophosmin in acute myelogenous leukemia with a normal karyotype.. N Engl J Med 2005; 352: 254–266). Hereby, we clarify the molecular mechanism underlying cytoplasmic NPM accumulation that yet remained to be elucidated. AML-associated mutated NPMalleles encode abnormal NPM proteins (25 mutants so far identified) which have acquired at the C-terminus a nuclear export signal-(NES) motif and lost at least one of tryptophan residues 288 and 290 which determine nucleolar localization. Both alterations are crucial for mutant NPM export from nucleus to cytoplasm. In fact, the cytoplasmic NPM accumulation is blocked by leptomycin-B and ratjadones which are specific inhibitors of exportin-1/CRM1, and by re-insertion of tryptophan residues 288 and 290, which respectively relocate NPM mutants in the nucleoplasm and nucleoli. Thus, for cytoplasmic accumulation of NPM to occur, the NES motif and tryptophan mutations must act in concert. Possibly, when NPM mutans enter the nucleus by virtue of their nuclear localization signals (NLS), their capability to bind nucleoli must be hindered at least partially to become a CRM-1 target. Specific antibodies anti-NPM mutant proteins showed that the mutants localized exclusively in the cytoplasm and recruited in that site the wild-type NPM protein which is physiologically located in the nucleoli. These findings suggest that the NPM mutants may interfere with the functions of wild-type NPM and possibly contribute to leukemogenesis. Immunostaining of 393 AML cases using anti-NPM monoclonal antibodies predicted the presence of NPMexon-12 mutations in all 191 NPM-cytoplasmic positive cases. This finding is consistent with the fact that, despite genomic heterogeneity, all NPM mutants contain a NES motif which, in the presence of altered tryptophans, promotes their rapid export from the nucleus to the cytoplasm. The immunohistochemical test is diagnostically relevant since it can be used as simple first-step procedure in molecular-genetic characterization of AML and as a surrogate for mutational analysis in selected cases. These findings are also clinically relevant since cytoplasmic NPM/NPM mutations are predictors of good response to induction therapy and favourable prognosis in AML with a normal karyotype.

Normal cytogenetics in AML is a major drawback to detect minimal residual disease. We have identified heterozygous NPM1 mutations as the most frequent genetic lesion in AML with normal karyotype (NEJM 2005:352,254). Mutations A, B and D, all characterized by tetranucleotide insertions, account for more than 90% of all mutations. NPM1 mutations are new important prognostic markers in AML with normal cytogenetics, being predictive of successful response to induction treatment (NEJM 2005:352,254) and longer overall survival in cases without FLT3 mutations (Dohner K et al, and Schnittger S et al, Blood 2005, on line). Their clinical impact prompted us to develop a Real Time Quantitative PCR assay for the identification and monitoring of NPM1 mutants.