ALBERT

Description: Nature Physics 9, 785 (2013). doi:10.1038/nphys2770 Authors: Michael Geiselmann, Renaud Marty, F. Javier García de Abajo & Romain Quidant The much sought after optical transistor—the photonic counterpart of the electronic transistor—is poised to become a central ingredient in the development of optical signal processing. The motivation for using photons rather than electrons comes not only from their faster dynamics, but also from their lower crosstalk and robustness against environmental decoherence, which enable a high degree of integration and the realization of quantum operations. A single-molecule transistor has recently been demonstrated at cryogenic temperatures. Here, we demonstrate that a single nitrogen–vacancy centre at room temperature can operate as an optical switch under non-resonant continuous-wave illumination. We show an optical modulation of more than 80% and a time response faster than 100 ns in the green-laser-driven fluorescence signal, which we control through an independent near-infrared gating laser. Our study indicates that the near-infrared laser triggers a fast-decay channel of the nitrogen–vacancy mediated by promotion of the excited state to a dark band.

Description: The probability laws associated to domain wall depinning under fields and currents have been studied in NiFe and FePt nanowires. Three basic domain wall depinning processes, associated to different potential landscapes, are found to appear identically in those systems with very different anisotropies. We show that these processes constitute the building blocks of any complex depinning mechanism. A Markovian analysis is proposed, that provides a unified picture of the depinning mechanism and an insight into the pinning potential landscape. Scientific Reports 4 doi: 10.1038/srep06509

Description: Pressure ulcers (PU) are serious, reportable events causing pain, infection and prolonged hospitalization, particularly among critically ill patients. The literature on PUs in neonates is limited. The objective was to determine the etiology, severity and influence of gestational age on PUs among hospitalized infants. A two-year prospective study was conducted among 741 neonatal intensive care patients over 31,643 patient-days. Risk factors were determined by comparing the characteristics of infants who developed PUs with those who did not. There were 1.5 PUs per 1000 patient days with 1.0 PU per 1000 days in premature infants and 2.7 per 1000 days in term infants. The number of PUs associated with devices was nearly 80% overall and over 90% in premature infants. Infants with PUs had longer hospitalizations and weighed more than those who did not. Infants with device-related PUs were younger, of lower gestational age and developed the PU earlier than patients with PUs due to conventional pressure. The time to PU development was longer in prematurely born versus term infants. Hospitalized neonates are susceptible to device-related injury and the rate of stage II injury is high. Strategies for early detection and mitigation of device-related injury are essential to prevent PUs. Scientific Reports 4 doi: 10.1038/srep07429

Description: Article In materials with strongly correlated electrons, charge carriers can separate into stripes of different electronic phases. Here, Anissimova et al. present evidence that in La 2−x Sr x NiO 4 these stripes can dynamically fluctuate, which helps to understand phenomena such as insulator–metal transitions. Nature Communications doi: 10.1038/ncomms4467 Authors: S. Anissimova, D. Parshall, G.D. Gu, K. Marty, M.D. Lumsden, Songxue Chi, J.A. Fernandez-Baca, D.L. Abernathy, D. Lamago, J.M. Tranquada, D. Reznik

Description: Calciodelrioite, ideally Ca(VO3)2(H2O)4, is a new mineral (IMA 2012-031) from the uranium-vanadium deposits of the eastern Colorado Plateau in the USA. The type locality is the West Sunday mine, Slick Rock district, San Miguel County, Colorado. The new mineral occurs on fracture surfaces in corvusite- and montroseite-impregnated sandstone and forms as a result of the oxidative alteration of these phases. At the West Sunday mine, calciodelrioite is associated with celestine, gypsum, huemulite, metarossite, pascoite and rossite. The mineral occurs as transparent colourless needles, bundles of tan to brown needles and star bursts of nearly black broad blades composed of tightly intergrown needles. Crystals are elongate and striated parallel to [100], exhibiting the prismatic forms {001} and {011} and having terminations possibly composed of the forms {100} and {611İ}. The mineral is transparent and has a white streak, subadamantine lustre, Mohs hardness of about 2, brittle tenacity, irregular to splintery fracture, one perfect cleavage on {001} and possibly one or more additional cleavages parallel to [100]. Calciodelrioite is soluble in water. The calculated density is 2.451 g cm−3. It is optically biaxial (+) with α = 1.733(3), β = 1.775(3), γ = 1.825(3) (white light), 2Vmeas = 87.3(9)° and 2Vcalc = 87°. The optical orientation is X = b; Z ≈ a. No pleochroism was observed. Electron-microprobe analyses of two calciodelrioite samples and type delrioite provided the empirical formulae (Ca0.88Sr0.07Na0.04K0.01)Σ1.00(V1.00O3)2(H2.01O)4, (Ca0.76Sr0.21Na0.01)Σ0.98(V1.00O3)2(H2.01O)4 and (Sr0.67Ca0.32)Σ0.99(V1.00O3)2(H2.00O)4, respectively. Calciodelrioite is monoclinic, I2/a, with unit-cell parameters a = 14.6389(10), b = 6.9591(4), c = 17.052(2) Å, β = 102.568(9)°, V = 1695.5(3)Å3 and Z = 8. The seven strongest lines in the X-ray powder diffraction pattern [listed as dobs Å(I)(hkl)] are as follows: 6.450(100)(011); 4.350(16)(013); 3.489(18)(020); 3.215(17)(022); 3.027(50)(multiple); 2.560(28)(41İ5,413); 1.786(18)(028). In the structure of calciodelrioite (refined to R1 = 3.14% for 1216 Fo 〉 4σF), V5+O5 polyhedra link by sharing edges to form a zigzag divanadate [VO3] chain along a, similar to that in the structure of rossite. The chains are linked via bonds to Ca atoms, which also bond to H2O groups, yielding CaO3(H2O)6 polyhedra. The Ca polyhedra form a chain along b. Each of the two symmetrically independent VO5 polyhedra has two short vanadyl bonds and three long equatorial bonds. Calciodelrioite and delrioite are isostructural and are the endmembers of the series Ca(VO3)2(H2O)4–Sr(VO3)2(H2O)4. Calciodelrioite is dimorphous with rossite, which has a similar structure; however, the smaller 8-coordinate Ca site in rossite does not accommodate Sr.

Description: Nestolaite (IMA 2013-074), CaSeO 3 ·H 2 O, is a new mineral species from the Little Eva mine, Grand County, Utah, USA. It is named in honour of the prominent Italian mineralogist and crystallographer Fabrizio Nestola. The new mineral was found on sandstone matrix as rounded aggregates up to 2 mm across and up to 0.05 mm thick consisting of tightly intergrown oblique-angled, flattened to acicular crystals up to 30 μm long and up to 7 μm (very rarely up to 15 μm) thick. Nestolaite associates with cobaltomenite, gypsum, metarossite, orschallite and rossite. The new mineral is light violet and transparent with a white streak and vitreous lustre. The Mohs hardness is 21/2. Nestolaite is brittle, has uneven fracture and perfect cleavage on {100}. The measured and calculated densities are D meas. = 3.18(2) g/cm 3 and D calc. = 3.163 g/cm 3 . Optically, nestolaite is biaxial positive. The refractive indices are α = 1.642(3), β = 1.656(3), = 1.722(6). The measured 2 V is 55(5)° and the calculated 2 V is 51°. In transmitted light nestolaite is colourless. It does not show pleochroism but has strong pseudo-absorption caused by high birefringence. The chemical composition of nestolaite (wt.%, electron-microprobe data) is: CaO 28.97, SeO 2 61.14, H 2 O (calc.) 9.75, total 99.86. The empirical formula calculated on the basis of 4 O a.p.f.u. (atoms per formula unit) is Ca 0.96 Se 1.02 O 3 ·H 2 O. The Raman spectrum is dominated by the Se–O stretching and O–Se–O bending vibrations of the pyramidal SeO 3 groups and O–H stretching modes of the H 2 O molecules. The mineral is monoclinic, space group P 2 1 /c , with a = 7.6502(9), b = 6.7473(10), c = 7.9358(13) Å, β = 108.542 (12)°, V = 388.37(10) Å 3 and Z = 4. The eight strongest powder X-ray diffraction lines are [ d obs inÅ ( hkl ) ( I rel )]: 7.277 (100)(100), 4.949 (110)(37), 3.767 (002)(29), 3.630 (200)(58), 3.371 (020)(24), 3.163 (2I02)(74), 2.9783 (1I21)(74) and 2.7231 (112)(31). The crystal structure of nestolaite was determined by means of the Rietveld refinement from the powder data to R wp = 0.019. Nestolaite possesses a layered structure consisting of Ca–SeO 3 sheets, composed of edge-sharing polyhedra. Adjacent sheets are held by H bonds emanating from the single (H 2 O) group within the sheets. The nestolaite structure is topologically unique.

Description: The new mineral belakovskiite (IMA2013-075), Na 7 (UO 2 )(SO 4 ) 4 (SO 3 OH)(H 2 O) 3 , was found in the Blue Lizard mine, Red Canyon, White Canyon district, San Juan County, Utah, USA, where it occurs as a secondary alteration phase in association with blödite, ferrinatrite, kröhnkite, meisserite and metavoltine. Crystals of belakovskiite are very pale yellowish-green hair-like fibres up to 2 mm long and usually no more than a few μm in diameter. The fibres are elongated on [100] and slightly flattened on {021}. Crystals are transparent with a vitreous lustre. The mineral has a white streak and a probable Mohs hardness of ~2. Fibres are flexible and elastic, with brittle failure and irregular fracture. No cleavage was observed. The mineral is readily soluble in cold H 2 O. The calculated density is 2.953 g cm –3 . Optically, belakovskiite is biaxial (+) with α = 1.500(1), β = 1.511(1) and = 1.523(1) (measured in white light). The measured 2V is 87.1(6)° and the calculated 2V is 88°. The mineral is non-pleochroic. The partially determined optical orientation is X a . Electron-microprobe analysis provided Na 2 O 21.67, UO 3 30.48, SO 3 40.86, H 2 O 6.45 (structure), total 99.46 wt.% yielding the empirical formula Na 6.83 (U 1.04 O 2 )(SO 4 ) 4 (S 0.99 O 3 OH)(H 2 O) 3 based on 25 O a.p.f.u. Belakovskiite is triclinic, P 1I, with a = 5.4581(3), b = 11.3288(6), c = 18.4163(13) Å, α = 104.786(7)°, β = 90.092(6)°, = 96.767(7)°, V = 1092.76(11) Å 3 and Z = 2. The eight strongest X-ray powder diffraction lines are [ d obs Å( I )( hkl )]: 8.96(35)(002), 8.46(29)(011), 5.19(100)(1I01,101,1I10), 4.66(58)(013,1I02,1I1I0,110), 3.568(37)(120,023,005,03I3), 3.057(59)(01I6,11I5,1I31), 2.930(27)(multiple) and 1.8320(29)(multiple). The structure, refined to R 1 = 5.39% for 3163 F o 〉 4 F reflections, contains [(UO 2 )(SO 4 ) 4 (H 2 O)] 6– polyhedral clusters connected via an extensive network of Na–O bonds and H bonds involving eight Na sites, three other H 2 O sites and an SO 3 OH (hydrosulfate) group. The 3-D framework, thus defined, is unique among known uranyl sulfate structures. The mineral is named for Dmitry Ilych Belakovskiy, a prominent Russian mineralogist and Curator of the Fersman Mineralogical Museum.

Description: Corrigendum Nature Communications doi: 10.1038/ncomms5385 Authors: S. Anissimova, D. Parshall, G. D. Gu, K. Marty, M. D. Lumsden, Songxue Chi, J. A. Fernandez-Baca, D. L. Abernathy, D. Lamago, J. M. Tranquada, D. Reznik

Description: Nature Materials 12, 426 (2013). doi:10.1038/nmat3581 Authors: Sviatlana Viarbitskaya, Alexandre Teulle, Renaud Marty, Jadab Sharma, Christian Girard, Arnaud Arbouet & Erik Dujardin

Description: Two new minerals – manganoblödite (IMA2012–029), ideally Na 2 Mn(SO 4 ) 2 ·4H 2 O, and cobaltoblödite (IMA2012–059), ideally Na 2 Co(SO 4 ) 2 ·4H 2 O, the Mn-dominant and Co-dominant analogues of blödite, respectively, were found at the Blue Lizard mine, San Juan County, Utah, USA. They are closely associated with blödite (Mn-Co-Ni-bearing), chalcanthite, gypsum, sideronatrite, johannite, quartz and feldspar. Both new minerals occur as aggregates of anhedral grains up to 60 μm (manganoblödite) and 200 μm (cobaltoblödite) forming thin crusts covering areas up to 2 x 2 cm on the surface of other sulfates. Both new species often occur as intimate intergrowths with each other and also with Mn-Co-Ni-bearing blödite. Manganoblödite and cobaltoblödite are transparent, colourless in single grains and reddish-pink in aggregates and crusts, with a white streak and vitreous lustre. Their Mohs' hardness is ~21/2. They are brittle, have uneven fracture and no obvious parting or cleavage. The measured and calculated densities are D meas = 2.25(2) g cm –3 and D calc = 2.338 g cm –3 for manganoblödite and D meas = 2.29(2) g cm –3 and D calc = 2.347 g cm –3 for cobaltoblödite. Optically both species are biaxial negative. The mean refractive indices are α = 1.493(2), β = 1.498(2) and = 1.501(2) for manganoblödite and α = 1.498(2), β = 1.503(2) and = 1.505(2) for cobaltoblödite. The chemical composition of manganoblödite (wt.%, electron-microprobe data) is: Na 2 O 16.94, MgO 3.29, MnO 8.80, CoO 2.96, NiO 1.34, SO 3 45.39, H 2 O (calc.) 20.14, total 98.86. The empirical formula, calculated on the basis of 12 O a.p.f.u., is: Na 1.96 (Mn 0.44 Mg 0.29 Co 0.14 Ni 0.06 ) 0.93 S 2.03 O 8 ·4H 2 O. The chemical composition of cobaltoblödite (wt.%, electron-microprobe data) is: Na 2 O 17.00, MgO 3.42, MnO 3.38, CoO 7.52, NiO 2.53, SO 3 45.41, H 2 O (calc.) 20.20, total 99.46. The empirical formula, calculated on the basis of 12 O a.p.f.u., is: Na 1.96 (Co 0.36 Mg 0.30 Mn 0.17 Ni 0.12 ) 0.95 S 2.02 O 8 ·4H 2 O. Both minerals are monoclinic, space group P 2 1 / a , with a = 11.137(2), b = 8.279(1), c = 5.5381(9) Å, β = 100.42(1)°, V = 502.20(14) Å 3 and Z = 2 (manganoblödite); and a = 11.147(1), b = 8.268(1), c = 5.5396(7) Å, β = 100.517(11)°, V = 501.97(10) Å 3 and Z = 2 (cobaltoblödite). The strongest diffractions from X-ray powder pattern [listed as ( d , Å( I )( hkl )] are for manganoblödite: 4.556(70)(210, 011); 4.266(45)(2I01); 3.791(26)(2I11); 3.338(21)(310); 3.291(100)(220, 021), 3.256(67)(211, 1I21), 2.968(22)(2I 21), 2.647(24)(4I01); for cobaltoblödite: 4.551(80)(210, 011); 4.269(50)(2I01); 3.795(18)(2I11); 3.339(43)(310); 3.29(100)(220, 021), 3.258(58)(211, 1I21), 2.644(21)(4I01), 2.296(22)(1I22). The crystal structures of both minerals were refined by single-crystal X-ray diffraction to R 1 = 0.0459 (manganoblödite) and R 1 = 0.0339 (cobaltoblödite).