Ballistic transport properties across nonuniform strain barriers in graphene

We study the effect of uniaxial strain on the transmission and the conductivity across a strain-induced barrier in graphene. At variance with conventional studies, which consider sharp barriers, we consider a more realistic, smooth barrier, characterized by a nonuniform, continuous strain profile. Our results are instrumental towards a better understanding of the transport properties in corrugated graphene.Comment: High Press. Res., to appea

Population expansion in the North African Late Pleistocene signalled by mitochondrial DNA haplogroup U6

Background <br/> The archaeology of North Africa remains enigmatic, with questions of population continuity versus discontinuity taking centre-stage. Debates have focused on population transitions between the bearers of the Middle Palaeolithic Aterian industry and the later Upper Palaeolithic populations of the Maghreb, as well as between the late Pleistocene and Holocene. <br/> Results Improved resolution of the mitochondrial DNA (mtDNA) haplogroup U6 phylogeny, by the screening of 39 new complete sequences, has enabled us to infer a signal of moderate population expansion using Bayesian coalescent methods. To ascertain the time for this expansion, we applied both a mutation rate accounting for purifying selection and one with an internal calibration based on four approximate archaeological dates: the settlement of the Canary Islands, the settlement of Sardinia and its internal population re-expansion, and the split between haplogroups U5 and U6 around the time of the first modern human settlement of the Near East. <br/> Conclusions <br/> A Bayesian skyline plot placed the main expansion in the time frame of the Late Pleistocene, around 20 ka, and spatial smoothing techniques suggested that the most probable geographic region for this demographic event was to the west of North Africa. A comparison with U6's European sister clade, U5, revealed a stronger population expansion at around this time in Europe. Also in contrast with U5, a weak signal of a recent population expansion in the last 5,000 years was observed in North Africa, pointing to a moderate impact of the late Neolithic on the local population size of the southern Mediterranean coast

Using m-health apps in oncology : A review from 2015 to 2022

The increased use of smartphones and the COVID-19 pandemic directly influenced the development of remote tools in several areas. In the context of oncology, it was no different, as several studies address health care or services related to mobile devices. Apps aimed at the medical field (m-health) focus directly on monitoring symptoms and improving interaction between health professionals and patients, combined with the convenience of smartphones. In this context, this work aims to address recent studies on the use of m-health in the clinical practice of oncological diseases and report the characteristics of the apps involved. For this, a review of m-health focused on oncology was conducted using the PubMed and Science Direct databases. The investigation was carried out using tools inherent in international databases and was limited to articles published between 2015 and 2022. In total, 34 articles were analyzed, with a higher frequency of publications between 2019 and 2022. The resources observed were patient follow-up, prevention of signs and symptoms, monitoring of treatment and aid in prognosis and diagnosis of patients. It is concluded that a close collaboration among patients, health professionals, and information technology professionals is necessary to optimize symptom recognition and improve patientprofessional communication. Although the pandemic has intensified the increase in the use of m-health, its use is expected to increase in the post-pandemic scenario, bearing in mind the changes in social dynamics and the growing dissemination of technologies.This work has been supported by Foundation for Science and Technology (FCT, Portugal) for financial support through national funds FCT/MCTES (PIDDAC) to CeDRI (UIDB/05757/2020 and UIDP/05757/2020), SusTEC (LA/P/0007/2021) and NORTE-01-0247-FEDER-072598 iSafety: Intelligent system for occupational safety and wellbeing in the retail sector. Laíres A. Lima thanks the Fundação para a Ciência e Tecnologia (FCT), Portugal, for the Ph.D. Grant 2022.13393.BD.info:eu-repo/semantics/publishedVersio

Entangled light in transition through the generation threshold

We investigate continuous variable entangling resources on the base of two-mode squeezing for all operational regimes of a nondegenerate optical parametric oscillator with allowance for quantum noise of arbitrary level. The results for the quadrature variances of a pair of generated modes are obtained by using the exact steady-state solution of Fokker-Planck equation for the complex P-quasiprobability distribution function. We find a simple expression for the squeezed variances in the near-threshold range and conclude that the maximal two-mode squeezing reaches 50% relative to the level of vacuum fluctuations and is achieved at the pump field intensity close to the generation threshold. The distinction between the degree of two-mode squeezing for monostable and bistable operational regimes is cleared up.Comment: 7 pages, 4 figures; Content changed: more details added to the discussion. To be published in Phys. Rev.

Nonclassical correlations of photon number and field components in the vacuum state

It is shown that the quantum jumps in the photon number n from zero to one or more photons induced by backaction evasion quantum nondemolition measurements of a quadrature component x of the vacuum light field state are strongly correlated with the quadrature component measurement results. This correlation corresponds to the operator expectation value which is equal to one fourth for the vacuum even though the photon number eigenvalue is zero. Quantum nondemolition measurements of a quadrature component can thus provide experimental evidence of the nonclassical operator ordering dependence of the correlations between photon number and field components in the vacuum state.Comment: 13 pages, 3 figures, corrections of omissions in equations (6) and (25). To be published in Phys. Rev.

Optimized quantum nondemolition measurement of a field quadrature

We suggest an interferometric scheme assisted by squeezing and linear feedback to realize the whole class of field-quadrature quantum nondemolition measurements, from Von Neumann projective measurement to fully non-destructive non-informative one. In our setup, the signal under investigation is mixed with a squeezed probe in an interferometer and, at the output, one of the two modes is revealed through homodyne detection. The second beam is then amplitude-modulated according to the outcome of the measurement, and finally squeezed according to the transmittivity of the interferometer. Using strongly squeezed or anti-squeezed probes respectively, one achieves either a projective measurement, i.e. homodyne statistics arbitrarily close to the intrinsic quadrature distribution of the signal, and conditional outputs approaching the corresponding eigenstates, or fully non-destructive one, characterized by an almost uniform homodyne statistics, and by an output state arbitrarily close to the input signal. By varying the squeezing between these two extremes, or simply by tuning the internal phase-shift of the interferometer, the whole set of intermediate cases can also be obtained. In particular, an optimal quantum nondemolition measurement of quadrature can be achieved, which minimizes the information gain versus state disturbance trade-off

Facile And Reversible Co Insertion Into The Ir-ch3 Bond Of [ir4(ch3)(co)8(μ4- η3-ph2pccph)(μ-pph2)]

Reaction of [Ir4H(CO)10 (μ-PPh2)] with BuLi, Ph2PC≡CPh and then Mel gives [Ir4 (CH 3)(CO)8 (μ4-η3-Ph 2PCCPh)(μ-PPh2)], which undergoes a reversible two-step CO insertion under extremely mild conditions to yield Ir4{(CH 3C(O)}(CO)8-(μ4:η3-Ph 2PCCPh)(μ-PPh2)] as the final product; the structures of both species have been established by X-ray diffraction studies.121008101

Induction of radiata pine somatic embryogenesis at high temperatures provokes a long-term decrease in dna methylation/hydroxymethylation and differential expression of stress-related genes

Based on the hypothesis that embryo development is a crucial stage for the formation of stable epigenetic marks that could modulate the behaviour of the resulting plants, in this study, radiata pine somatic embryogenesis was induced at high temperatures (23¿ C, eight weeks, control; 40¿ C, 4 h; 60¿ C, 5 min) and the global methylation and hydroxymethylation levels of emerging embryonal masses and somatic plants were analysed using LC-ESI-MS/ MS-MRM. In this context, the expression pattern of six genes previously described as stress-mediators was studied throughout the embryogenic process until plant level to assess whether the observed epigenetic changes could have provoked a sustained alteration of the transcriptome. Results indicated that the highest temperatures led to hypomethylation of both embryonal masses and somatic plants. Moreover, we detected for the first time in a pine species the presence of 5-hydroxymethylcytosine, and revealed its tissue specificity and potential involvement in heat-stress responses. Additionally, a heat shock protein-coding gene showed a down-regulation tendency along the process, with a special emphasis given to embryonal masses at first subculture and ex vitro somatic plants. Likewise, the transcripts of several proteins related with translation, oxidative stress response, and drought resilience were differentially expressed

Synthesis And Structural Characterisation Of [ir4(co)8(ch3)(μ4-η 3-ph2pccph)(μ-pph2)] And Of The Carbonylation Product [ir4(co)8{c(o)ch3}(μ4-η 3-ph2pccph)(μ-pph2)]

Deprotonation of [(μ-H)Ir4(CO)10(μ-PPh2)], 1, gives [Ir4(CO)10(μ-PPh2)]- that reacts with Ph2PCCPh and CH3I to afford [Ir4(CO)8(CH3)(μ4-η 3-Ph2PCCPh)(μ-PPh2)], 2 (34%), besides [Ir4(CO)9(μ3-η3-Ph 2PC(H)CPh)(μ-PPh2)] and [(μ-H)Ir4(CO)9(Ph2PC≡CPh)(μ-PPh2)]. Compound 2 was characterised by a single crystal X-ray diffraction analysis and exhibits a flat butterfly of metal atoms, with the Ph2PCCPh ligand interacting with all four Ir atoms and the methyl group bonded terminally to a wingtip Ir atom. Carbonylation of 2 yields initially (25°C, 20 min) a CO addition product that, according to VT 31P{1H} and 13C{1H} studies, exists in solution in the form of two isomers 4A and 4B (8:1), and then (40°C, 7 h), the CO insertion product [Ir4(CO)8{C(O)CH3}-(μ4-η 3-Ph2PCCPh)(μ-PPh2)], 5. The molecular structure of 5, established by an X-ray analysis, is similar to that of 2, except for the acyl group that remains bound to the same Ir atom. The process is reversible at both stages. Treatment of 2 with PPh3 and P(OMe)3 affords the CO substitution products [Ir4(CO)7L(CH3)(μ4-η 3-Ph2PCCPh)(μ-PPh2)] (L = PPh3, 6 and P(OMe)3, 7), instead of the expected CO inserted products. According to the 1H and 31P{1H} NMR studies, the PPh3 derivative 6 exists in the form of two isomers (1:1) that differ with respect to the position of this ligand.1013545Hoffmann, R., (1982) Angew. Chem. Int. Ed. Engl., 21, p. 711Bau, R., Chiang, M.Y., Wei, C.-Y., Garlaschelli, L., Martinengo, S., Koestzle, T.F., (1984) Inorg. Chem., 23, p. 4758Ragaini, F., Porta, F., Demartin, F., (1991) Organometallics, 10, p. 185Albano, V.G., Canziani, F., Ciani, G., Chini, P., Martinengo, S., Manassero, M., Giordano, G., (1978) J. Organomet. Chem., 150, pp. C17Chinara, T., Aoki, K., Yamazaki, H., (1990) J. Organomet. Chem., 353, p. 367Chinara, T., Aoki, K., Yamazaki, H., (1994) J. Organomet. Chem., 473, p. 273González-Moraga, (1993) Cluster Chemistry, , Chapter 3, Springer-Verlag, BerlinBenvenutti, M.H.A., Vargas, M.D., Braga, D., Grepioni, F., Parisini, E., Mann, B.E., (1993) Organometallics, 12, p. 2955Benvenutti, M.H.A., Vargas, M.D., Braga, D., Grepioni, F., Mann, B.E., Naylor, S., (1993) Organometallics, 12, p. 2947Yamamoto, A., (1986) Organotransition Metal Chemistry, , WileyMorison, E.D., Bassner, L.S.L., Geoffroy, G.L., (1986) Organometallics, 5, p. 408Pereira, R.M.S., Fujiwara, F.Y., Vargas, M.D., Braga, D., Grepioni, F., (1997) Organometallics, 16, p. 4833Delgado, E., Chi, Y., Wang, W., Horgath, G., Low, P.J., Enright, G.D., Peng, S.-M., Carty, A.J., (1998) Organometallics, 17, p. 2936Vargas, M.D., Pereira, R.M.S., Braga, D., Grepioni, F., (1993) J. Chem. Soc. Chem. Commun., p. 1008Hengefelt, A., Nast, R., (1983) Chem. Ber., 116, p. 2025Livotto, F.S., Raithby, P.R., Vargas, M.D., (1993) J. Chem. Soc. Dalton Trans., p. 1797Brauer, G., (1965) Handboock of Preparative Inorganic Chemistry, 1, p. 645Sheldrick, G.M., (1990) Acta Crystallogr., A46, p. 467Sheldrick, G.M., (1976) SHELX76, Program for Crystal Structure Determination, , University of Cambridge, Cambridge, EnglandWalker, N., Stuart, D., (1983) Acta Crystallogr., Sect. B, 39, p. 158Keller, E., (1992) SHAKAL92, Graphical Representation of Molecular Models, , University of Freiburg, FRGKubota, M., McClesky, T.M., Hayashi, R.K., Carl, G., (1987) J. Am. Chem. Soc., 109, p. 7569Wade, K., (1976) Adv. Inorg. Chem. Radiochem., 18, p. 1Benvenutti, M.H.A., Vargas, M.D., Hitchcock, P.B., Nixon, J.F., (1995) J. Chem. Soc. Chem. Commun., p. 866Carty, A.J., Mac Laughlin, S.A., Nucciaroni, D., (1987) Phosphorus 31-NMR Spectroscopy in Steereochemical Analysis of Organic Compounds and Metal Complexes, , Chapter 16Verkade, J. G.Quin, L. D. EdsVCHKeister, J.B., (1980) J. Organomet. Chem., 190, pp. C36Aime, S., Dastrù, W., Gobetto, R., Viale, A., (1998) Organometallics, 17, p. 3182Johnson, B.F.G., Lewis, J., Orpen, A.G., Raithby, P.R., Süss, G., (1979) J. Organomet. Chem., 173, p. 187Araujo, M.H., Vargas, M.D., unpublished resultsMonti, D., Frachey, G., Bassetti, M., Haynes, A., Sunley, G.J., Maitlis, P.M., Cantoni, A., Bocelli, G., (1995) Inorg. Chim. Acta, 240, p. 485Garcia Alonso, J., Llamazares, A., Riera, V., Diaz, M.R., García Grande, S., (1991) J. Chem. Soc. Chem. Commun., p. 1058Cotton, J.D., Crisp, G.T., Daly, V.A., (1981) Inorg. Chim. Acta, 47, p. 165Bondietti, G., Laurenczy, G., Ross, R., Roulet, R., (1994) Helv. Chim. Acta, 77, p. 1869Laurenczy, G., Bondietti, G., Merbach, A.E., Moulet, B., Roulet, R., (1994) Helv. Chim. Acta, 77, p. 547Braga, D., Grepioni, F., Vargas, M.D., Ziglio, C.M., manuscript in preparatio

Structural and solution speciation studies on selected [Cu(NN)(OO)] complexes and an investigation of their biomimetic activity, ROS generation and their cytotoxicity in normoxic, hypoxic and anoxic environments in MCF-7 breast cancer-derived cells

Reactive oxygen species(ROS) generation with subsequent DNA damage is one of the principle mechanisms of action assigned to copper-based anticancer complexes. The efficacy of this type of chemotherapeutic may be reduced in the low oxygen environment of tumours. In this study the cytotoxicity of three complexes, [Cu(dips)(phen)] (1), [Cu(ph)(phen)]·2H2O (2) and [Cu(ph)(bpy)]·H2O (3) (disp: 3,5-diisopropylsalicylate, phen: 1,10- phenanthroline, ph: phthalate, bpy: 2,2′-bipyridyl) were assessed for anticancer activity in the breast-cancer derived MCF-7 line under normoxic, hypoxic and anoxic conditions. In an immortalised keratinocyte HaCaT cell line, the cytotoxicity of complexes 2 and 3 was significantly reduced under both normoxic and hypoxic conditions, whilst the cytotoxicity of complex 1 was increased under hypoxic conditions. The ability of the complexes to generate ROS in the MCF-7 cell line was evaluated as was their ability to act as superoxide dismutase(SOD) and catalase mimics using a yeast cell assay. ROS generation was significant for complexes 2 and 3, less so for complex 1 though all three complexes had SOD mimetic ability. Given the ternary nature of the complexes, solution speciation studies were undertaken but were only successful for complex 3, due to solubility issues with the other two complexes. The concentration distribution of various species, formed in aqueous solution, was evaluated as a function of pH and confirmed that complex 3 is the dominant species at physiological pH in the mM concentration range. However, as its concentration diminishes, it experiences a progressive dissociation, leading to the formation of binary complexes of bpy alongside unbound phthalate. © 2023 The Author