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The reactions of the phosphanylborane Ph2PBH2•NMe3 (L) with Ag[FAl{OC6F10(C6F5)}3] (Ag[FAl]) and AgBF4 are studied. The first reaction allowed for the synthesis of the coordination compounds [Ag(Ph2P-BH2•NMe3)(CH3CN)][FAl] (1), [Ag(Ph2PBH2•NMe3)2][FAl] (2) and [Ag(Ph2PBH2•NMe33)3][FAl] (3), while the second reaction afforded the one-dimensional coordination polymer [Ag(Ph2PBH2•NMe3)]n[BF4]n (4). Compounds 1-4 are the first reported Ag(I) complexes stabilised by phosphanylboranes. [ABSTRACT FROM AUTHOR]

Abstract: We report on depolymerization reactions of poly(phosphinoboranes). The cleavage of the polymers [H2PBH2]n (2 a), [tBuHPBH2]n (2 c), [PhHPBH2]n (2 e) and the oligomer [Ph2PBH2]n (2 b), with strong Lewis bases (LBs), in particular with NHCs, leads to the corresponding monomeric phosphanylboranes R1R2PBH2LB. It is observed that the depolymerization depends on the strength and stability of the LBs as well as on the substitution pattern of the poly(phosphinoboranes). The solid state structures of the monomeric phosphinoboranes H2PBH2NHCMe (NHC=N‐heterocyclic carbene) (4 a), H2PBH2NHCdipp (5 a) and tBuHPBH2NHCMe (4 c) were determined. DFT calculations support the experimentally observed reaction behavior. [ABSTRACT FROM AUTHOR]

The reactions of the monomeric phosphanylboranes Ph2P-BH2 ·NMe3 ( 1a) and tBuHP-BH2 ·NMe3 ( 1b) with the main group Lewis acids BH3 and BBr3 yield the adducts H3B ·Ph2P-BH2 ·NMe3 ( 2a) and H3B · tBuHP-BH2 ·NMe3 ( 2b), Br3B ·Ph2P-BH2 ·NMe3 ( 3a), and Br3B · tBuHP-BH2 ·NMe3 ( 3b). All these compounds were completely characterized by single-crystal X-ray structure analysis, NMR and IR spectroscopy as well as mass spectrometry and DFT computations. The secondary and tertiary phosphines 1a and 1b behave as classical Lewis bases to coordinate B X3 ( X = H, Br) as terminal groups. [ABSTRACT FROM AUTHOR]

We report on the synthesis and characterization of mixed pnictogenylboranes. The substitution of the Lewis base SMe2 in (OC)5W-PH2BH2-SMe2 ( 2) by different pnictogenylboranes ER2BH2-LB (E=P, As, Sb) leads to the Lewis acid/base stabilized butane analogue (OC)5W-PH2BH2ER2BH2-LB ( 3 a, b: E=P; R=H, SiMe3; LB=NMe3; 4 a, b: E=As; R=H, SiMe3; LB=NMe3; 5: E=Sb; R=SiMe3; LB=NHCMe). All of these compounds were characterized by single-crystal X-ray structure analysis, mass spectrometry, NMR, and IR spectroscopy. In addition, the very unstable phosphanylborane chain PH2BH2PH2BH2-NMe3 ( 1) was synthesized. DFT calculations provide insight into the thermodynamics of these reactions. [ABSTRACT FROM AUTHOR]

Wir berichten über die Synthese und Charakterisierung von gemischten Pnictogenylboranen. Die Substitution der Lewis ‐ Base SMe2 in (OC)5W ‐ PH2BH2 ‐ SMe2 (2) durch verschiedene Pnictogenylborane ER2BH2 ‐ LB (E=P, As, Sb) führt zu den Lewis ‐ Säure/Base ‐ stabilisierten, Butan ‐ analogen Molekülen (OC)5W ‐ PH2BH2ER2BH2 ‐ LB (3 a,b: E=P, R=H, SiMe3, LB=NMe3; 4 a,b: As, R=H, SiMe3, LB=NMe3; 5: Sb, R=SiMe3, LB=NHCMe). Alle Verbindungen wurden durch Einkristall ‐ Röntgenstrukturanalyse, Massenspektrometrie, NMR ‐ und IR ‐ Spektroskopie charakterisiert. Darüber hinaus wurde die sehr instabile Phosphanylboran ‐ Kette PH2BH2PH2BH2 ‐ NMe3 (1) synthetisiert. Dichtefunktionalrechnungen geben Einblick in die Thermodynamik dieser Reaktionen. Vermischung! Durch die Anwendung der Donor/Akzeptor ‐ Stabilisierung wurden neutrale Pnictogenylborane ((OC)5W ‐ PH2BH2ER2BH2 ‐ LB; E=P, As, Sb; R=H, SiMe3) erhalten. Nach Substitution von SMe2 in (OC)5W ‐ PH2BH2 ‐ SMe2 durch Lewis ‐ Base ‐ stabilisierte Pnictogenylborane konnten die ersten neutralen Moleküle mit P ‐ B ‐ As ‐ B ‐ Kette oder P ‐ B ‐ Sb ‐ B ‐ Einheit isoliert werden. [ABSTRACT FROM AUTHOR]

The substituted monomeric phosphanylboranes Ph2P−BH2 ⋅NMe3 ( 1) and tBuHP−BH2 ⋅NMe3 ( 2) have been used for the synthesis of cationic chain compounds built up by R2P−BH2 units. With a simple synthesis route, the highly stable cations [Me3N ⋅H2B−PR1R2−BH2 ⋅NMe3]+ ( 1 a, 2 a) and [Me3N ⋅H2B−PR1R2−BH2−PR1R2−BH2 ⋅NMe3]+ ( 1 b, 2 b) (R1=R2=Ph; R1=H, R2= tBu) are obtained as iodide (I−) salts. The reaction of H2As−BH2 ⋅NMe3 ( 3) with IBH2 ⋅SMe2 leads to [Me3N ⋅H2B−AsH2−BH2−AsH2−BH2 ⋅NMe3][I] ( 3 a), the longest so far known arsanylborane chain. Compound 3 a reacts with acetonitrile through a formal hydroarsination reaction to form [cyclo-{As(BH2 ⋅NMe3)(CMe=NH)2(BH2)}][I] ( 4). The reported synthetic strategy has proved to be a powerful tool for the formation of small, cationic oligomeric units. All products were comprehensively characterized by X-ray structure analysis, NMR, IR spectroscopy, and mass spectrometry in cooperation with DFT calculations. [ABSTRACT FROM AUTHOR]

We modified an epi-illumination light microscope and mounted it on an ultra high vacuum chamber for investigating samples used in a surface science experiment. For easy access and bake out, all optical components are placed outside the vacuum and the sample is imaged through a glass window. The microscope can be operated in reflection brightfield or epifluorescence mode to image the sample surface or fluorescent dye molecules adsorbed on it. The homemade sample mounting was made compatible for the use under the microscope; sample temperatures as low as 6 K can be achieved. The performance of the microscope is demonstrated on two model samples: Brightfield-images of a well-prepared Ag(100) surface show a macroscopic corrugation of the surface, although low energy electron diffraction data indicate a highly ordered crystalline surface. The surface shows macroscopic protrusions with flat regions, about 20-200 µm in diameter, in between. Fluorescence images of diluted 3,4,9,10-perylene tetracarboxylicacid dianhydride (PTCDA) molecules adsorbed on an ultrathin epitaxial KCl film on the Ag(100) surface show a shading effect at surface protrusions due to an inclined angle of incidence of the PTCDA beam during deposition. For some preparations, the distribution of the fluorescence intensity is inhomogeneous and shows a dense network of bright patches about 5 µm in diameter related to the macroscopic corrugation of the surface. We propose that such a light microscope can aid many surface science experiments, especially those dealing with epitaxial growth or fluorescent materials. [ABSTRACT FROM AUTHOR]

The elemental chalcogens sulfur, selenium, tellurium and bis(trimethylsilyl)peroxide as an oxygen source are applied for the oxidation of the phosphanylboranes Ph2P-BH2⋅NMe3 ( 1) and tBuHP-BH2⋅NMe3 ( 2). The corresponding monooxidation products Ph2P(X)-BH2⋅NMe3 (X=O-Te, 3 a- d) and tBuHP(X)-BH2⋅NMe3 (X=O-Te, 4 a- d) were obtained in good yields and comprehensively characterized by single crystal X-ray structure analysis, NMR, IR spectroscopy and mass spectrometry. The first oxidation step proceeds very selectively for all chalcogenides. For the tBu derivative, a further oxidation can be realised with O2, S8 and Se yielding tBu(HX)P(X)-BH2⋅NMe3 (X=O, S, Se, 5 a- c). The telluride compounds presented herein are the first examples of neutral Te-substituted phosphanylboranes. [ABSTRACT FROM AUTHOR]

We report on the synthesis and structural characterization of unprecedented anionic parent compounds of mixed Group 13/15 elements. The reactions of the pnictogenylboranes H2E-BH2⋅NMe3 ( 1 a=P, 1 b=As) with phosphorus and arsenic centered nucleophiles of the type [EH2]− (E=P, As) lead to the formation of compounds of the type [H2E-BH2-E′H2]− ( 2: E=E′=P; 3: E=E′=As; 4: E=P, E′=As) containing anionic pnictogen-boron chain-like units. Furthermore, a longer 5-membered chain species [H2As-BH2-PH2-BH2-AsH2]− ( 5) and a cyclic compound [NHCdipp-H2B-PH2-BH2-NHCdipp]+[P5B5H19]− ( 6) containing a n-butylcyclohexane-like anion were obtained. All the compounds have been characterized by X-ray structure analysis, multinuclear NMR spectroscopy, IR spectroscopy, and mass spectrometry. DFT calculations elucidate their high thermodynamic stability, the charge distribution, and give insight into the reaction pathway. [ABSTRACT FROM AUTHOR]

Wir berichten über die Synthese und strukturelle Charakterisierung von präzedenzlosen anionischen Stammverbindungen aus gemischten Elementen der Gruppen 13 und 15. Die Reaktionen der Pnictogenylborane H2E ‐ BH2⋅NMe3 (1 a: E=P; 1 b: E=As) mit phosphor ‐ und arsenzentrierten Nukleophilen der Form [EH2]− (E=P, As) führen zur Bildung von Verbindungen des Typs [H2E ‐ BH2 ‐ E′H2]− (2: E=E′=P; 3: E=E′=As; 4: E=P, E′=As), die kettenartige anionische Pnictogen ‐ Bor ‐ Einheiten enthalten. Darüber hinaus wurden die längere, fünfgliedrige Kette [H2As ‐ BH2 ‐ PH2 ‐ BH2 ‐ AsH2]− (5) und die Ringverbindung [NHCdipp ‐ H2B ‐ PH2 ‐ BH2 ‐ NHCdipp]+[P5B5H19]− (6) mit n ‐ Butylcyclohexan ‐ ähnlichem Anion hergestellt. Alle Verbindungen wurden durch Röntgenstrukturanalyse, Multikern ‐ NMR ‐ und IR ‐ Spektroskopie sowie Massenspektrometrie charakterisiert. Dichtefunktionalrechnungen erklären ihre hohe thermodynamische Stabilität und geben Aufschluss über Ladungsverteilung und Reaktionsverlauf. Letztlich durchweg negativ! Durch Alkalimetallphosphanide und ‐ arsenide können die Stammverbindungen der Phosphanyl ‐ und Arsanylborane leicht in lineare anionische Kettenmoleküle umgewandelt werden. Sie sind einzigartige Vertreter der Klasse der anionischen Pnictogenylborane und konnten strukturell charakterisiert werden. [ABSTRACT FROM AUTHOR]

Mild thermolysis of Lewis base stabilized phosphinoborane monomers R1R2PBH2⋅NMe3 (R1,R2=H, Ph, or tBu/H) at room temperature to 100 °C provides a convenient new route to oligo- and polyphosphinoboranes [R1R2P-BH2]n. The polymerization appears to proceed via the addition/head-to-tail polymerization of short-lived free phosphinoborane monomers, R1R2P-BH2. This method offers access to high molar mass materials, as exemplified by poly( tert-butylphosphinoborane), that are currently inaccessible using other routes (e.g. catalytic dehydrocoupling). [ABSTRACT FROM AUTHOR]

Die milde Thermolyse der Lewis ‐ Base ‐ stabilisierten Phosphanylboran ‐ Monomere R1R2P ‐ BH2⋅NMe3 (R1,R2=H, Ph oder tBu/H) von Raumtemperatur bis 100 °C ist eine bequeme Synthesemethode für Oligo ‐ und Poly(phosphanylborane) [R1R2P ‐ BH2]n. Die Polymerisation scheint über eine Additions ‐ /Kopf ‐ Schwanz ‐ Polymerisation kurzlebig, freier Phosphanylboran ‐ Monomere, R1R2P ‐ BH2, zu verlaufen. Diese Methode liefert hochmolekulare Materialien, wie durch Poly(tert ‐ butylphosphanylborane) veranschaulicht, die gegenwärtig auf anderen Wegen (z. B. katalytische dehydrierende Kupplung) nicht zugänglich sind. Die milde Thermolyse von Lewis ‐ Base ‐ stabilisierten Phosphanylboran ‐ Monomeren ist eine vielversprechende Syntheseroute für Oligo ‐ und Poly(phosphanylborane). Die Polymerisation scheint über eine Additions ‐ /Kopf ‐ Schwanz ‐ Polymerisation kurzlebiger Phosphanylboran ‐ Monomere zu erfolgen. Diese Methode liefert Poly(alkylphosphanylborane) mit hohen Molmassen, die gegenwärtig über andere übergangsmetallkatalysierte Methoden nicht zugänglich sind. [ABSTRACT FROM AUTHOR]

We investigated the growth of NaCl on thin (100)-oriented films of KCl by spot profile analysis of low energy electron diffraction (SPA-LEED). The underlying question of this investigation was how the system accommodates to the misfit of − 10% between the NaCl and KCl lattices. The KCl films (3 atomic layers thick) were epitaxially grown on a Ag(100) single crystal. We studied the heteroepitaxial growth of NaCl on KCl at 300 K and at 500 K, respectively. At 300 K, the first NaCl monolayer (ML) grows pseudomorphically on the KCl film. From the second layer onward, the NaCl lattice relaxes. The NaCl multilayers roughen, and a small rotational disorder (± 4°) of the NaCl domains is observed. The roughening results from the formation of multilayer islands of limited lateral size due to the misfit to the pseudomorphic first NaCl layer. At a growth temperature of 500 K, no pseudomorphic NaCl layer forms, instead relaxed multilayer island growth of NaCl is observed from the first layer onward. Similarly to the growth at 300 K, we find NaCl multilayer islands of limited lateral size. For both temperatures, we explain this growth behavior by the misfit that makes the adsorption sites at the island edges of the first relaxed NaCl layer less favorable for larger islands, promoting nucleation of multilayer islands. [ABSTRACT FROM AUTHOR]

The synthesis of the Lewis base stabilized monomeric parent compound of stibanylboranes, 'H2SbBH2', is reported. Through a salt metathesis route, the silyl-substituted compounds (Me3Si)2SbBH2⋅LB (LB=NMe3, NHCMe) were synthesized as representatives of derivatives with a SbB σ bond. Under very mild conditions, they could be transformed into the target compounds Me3N⋅H2BHSbBH2⋅NMe3 and H2SbBH2⋅NHCMe, respectively. The products were characterized by X-ray structure analysis, NMR spectroscopy, IR spectroscopy, and mass spectrometry. DFT calculations give further insight into the stability and bonding of these unique compounds. [ABSTRACT FROM AUTHOR]

Wir berichten über die Synthese der Lewis ‐ Base ‐ stabilisierten monomeren Stammverbindung des Stibanylborans, “H2Sb ‐ BH2”. Über eine Salzmetathese wurden die silylsubstituierten Verbindungen (Me3Si)2Sb ‐ BH2⋅LB (LB=NMe3, NHCMe) synthetisiert, die Derivate mit einer Sb ‐ B ‐ σ ‐ Bindung repräsentieren. Unter sehr milden Bedingungen konnten sie in die Zielverbindungen Me3N⋅H2B ‐ HSb ‐ BH2⋅NMe3 bzw. H2Sb ‐ BH2⋅NHCMe überführt werden. Die Produkte wurden durch Röntgenstrukturanalyse, NMR ‐ Spektroskopie, IR ‐ Spektroskopie und Massenspektrometrie charakterisiert. Dichtefunktionalrechnungen geben weitere Einblicke in die Stabilität und die Bindungsverhältnisse dieser einzigartigen Verbindungen. Schwerer werdend! Die nur durch eine Lewis ‐ Base stabilisierte monomere Stammverbindung der Stibanylborane, „H2Sb ‐ BH2”︁, wurde isoliert und vollständig charakterisiert. Dichtefunktionalrechnungen geben weiteren Einblick in die Stabilität dieser einzigartigen Verbindungen. [ABSTRACT FROM AUTHOR]

An unprecedented family of three‐ and five‐membered substituted anionic derivatives of parent pnictogenylboranes is herein reported. Reacting various combinations of the pnictogenylboranes H2E′−BH2−NMe3 (E′=P, As) with pnictogen‐based nucleophiles MER1R2 (E=P, As; R1=H, R2=tBu; R1=R2=Ph; M=Na, K) allows for the isolation of the unsymmetrical products [Na(18‐crown‐6)][H2E′−BH2−EHtBu] (3: E=E′=P; 4: E=E′=As; 5: E=As, E′=P) and [M(C)][H2E′−BH2−EPh2] (7: E=E′=P, M=Na, C=18‐crown‐6; 8: E=E′=As; M=K, C=[2.2.2]cryptand; 9: E=P, E′=As, M=Na, C=[2.2.2]cryptand; 10: E=As, E′=P, M=K, C=[2.2.2]cryptand). [Na(18‐crown‐6)][H2As−BH2‐tBuPH−BH3] (6) is only accessible by a different pathway, using tBuPH2, BH3 ⋅ SMe2 and NaNH2 as starting materials. Additionally, the synthesis of symmetrical diphenyl‐substituted compounds [M(18‐crown‐6)][Ph2E−BH2−EPh2] (11: E=P, M=Na; 12: E=As, M=K) is reported which can be regarded as isostructural inorganic, negatively charged analogs of dppm (1,1‐bis(diphenylphosphino)methane) and dpam (1,1‐bis(diphenylarsino)methane). Furthermore, an elongation of the pnictogen boron backbone in compounds 3, 7 and 9′ (similar compound to 9, stabilized however by 18‐crown‐6), is attainable by reacting them with the pnictogenylboranes H2E′−BH2−NMe3 leading to corresponding five‐membered chain‐like compounds [Na(18‐crown‐6)][H2E−BH2−R1R2P−BH2−E′H2] (E=E′=P, R1=H, R2=tBu (13); E=E′=P, R1=R2=Ph (14); E=E′=As, R1=R2=Ph (15); E=P, E′=As, R1=R2=Ph (16)). Finally, the thermodynamics of the reaction pathways were evaluated by quantum chemical computations. [ABSTRACT FROM AUTHOR]

Converting left-handers to their non-dominant right hand was previously widespread, particularly for handwriting. The present study aimed to explore the extent to which adult, converted left-handers can learn writing with their dominant left hand during a 2-year training program. Eleven converted left-handers participated in the training. Handwriting kinematics were assessed at regular intervals (seven sessions) and compared to those of 11 innate left-handed controls matched for age, gender, and overall handedness score for basic (Finger, Wrist, Circle) and complex (Sentence, Copy) handwriting tasks. Regarding basic tasks in the training group, we found rapid increases in left and right-hand frequency and no significant differences between both hands at any time point, indicating successful hand transfer. After 24 months, training participants significantly surpassed controls for writing frequency in basic tasks with their left hand. For complex tasks, we identified significant increases in the training groups' left-hand writing frequency and duration between the first and last session. While training participants' left-hand writing remained significantly slower than their right-hand writing, statistics confirmed final differences between hands only for the duration of the Sentence task. Importantly, left-hand writing in the training group was characterized by lower frequency, lower automaticity, and prolonged duration after 24 months compared to innate left-handers. With training participants' left-hand writing skills significantly increasing for complex tasks and no final statistically significant differences between hands for frequency and automaticity, the program was considered effective. Nevertheless, within 2 years, training participants did not reach innate left-handers handwriting proficiency for complex tasks. Underlying reasons may be various, such as a non-optimal training program, a sensitive period for learning to write, irreversible neural changes during conversion in childhood, age-related decline of motor learning capacity, or retrograde interference between right- and left-hand writing. [ABSTRACT FROM AUTHOR]

Whilst catena-phosphorus cations have been intensively studied in the last years, mixed Group 13/15 element cationic chains have not yet been reported. Reaction of the pnictogenboranes H2EBH2⋅NMe3 (E=P, As) with monohalideboranes lead to the cationic chain compounds [Me3N⋅BH2EH2BH2⋅NMe3][X] (E=P, As; X=AlCl4, I) and [Me3N⋅BH2PH2BH2PH2BH2⋅NMe3][X] (X=I, VCl4(thf)2), respectively. All of the compounds have been characterized by X-ray structure analysis, NMR spectroscopy, IR spectroscopy, and mass spectrometry. DFT calculations elucidate the reaction pathway, the high thermodynamic stability, the charge distribution within the chain and confirm the observed solid-state structures. [ABSTRACT FROM AUTHOR]

Während catena ‐ Phosphorkationen innerhalb der letzten Jahre intensiv untersucht wurden, gab es über gemischte kationische Ketten aus Gruppe ‐ 13 ‐ und Gruppe ‐ 15 ‐ Elementen bislang keine Berichte. Die Umsetzung der Pnictogenborane H2EBH2⋅NMe3 (E=P, As) mit Monohalogenboranen führt zu den kationischen Kettenverbindungen [Me3N⋅BH2EH2BH2⋅NMe3][X] (E=P, As; X=AlCl4, I) und [Me3N⋅BH2PH2BH2PH2BH2⋅NMe3][X] (X=I, VCl4(thf)2). Alle Verbindungen wurden durch Röntgenstrukturanalyse, NMR ‐ Spektroskopie, IR ‐ Spektroskopie und Massenspektrometrie charakterisiert. DFT ‐ Rechnungen erklären den Reaktionsverlauf, die hohe thermodynamische Stabilität und die Ladungsverteilung innerhalb der Kette und bestätigen die beobachteten Festkörperstrukturen. Anorganische Alkane: Monomere Bausteine aus Elementen der Gruppen 13 und 15 – H2EBH2⋅NMe3 (E=P, As) – wurden in guten Ausbeuten zu kationischen Ketten umgesetzt. Die Produkte enthalten ein Rückgrat aus alternierenden B ‐ und P ‐ bzw. As ‐ Atomen, die ausschließlich Wasserstoffatome tragen. Dichtefunktionalrechnungen geben Einblick in Bildung, Bindungsverhältnisse und Strukturparameter dieser anorganischen Analoga kationischer Kohlenwasserstoffe. [ABSTRACT FROM AUTHOR]

Exclusively hydrogen‐substituted arsanylboranes: The synthesis of the unprecedented Lewis base stabilized monomeric parent compound of the arsanylborane H2AsBH2⋅NMe3 was achieved in a one‐pot reaction in high yield and purity. The analogous phosphanylborane was synthesized in a similar manner. A series of different reactions was performed on H2AsBH2⋅NMe3 to show its broad reactivity pattern. [ABSTRACT FROM AUTHOR]

The PB chain gang: The reactions of an acetylene complex of titanocene with the parent phosphinoborane stabilized only by a Lewis base lead to novel phosphinoborane oligomers coordinated by {Cp2Ti} complex fragments. Depending on the reaction conditions (temperature and stoichiometry), unprecedented oligomeric chains of phosphinoborane are obtained by dehydro‐oligomerization and PP coupling reactions. btmsa = bis(trimethylsilyl)acetylene. [ABSTRACT FROM AUTHOR]

Die Stammverbindung Phosphanylboran, nur durch eine Lewis ‐ Base stabilisiert, reagiert mit einem Titanocen ‐ Acetylenkomplex zu neuen Phosphanylboran ‐ Oligomeren, die durch {Cp2Ti} ‐ Komplexfragmente koordiniert werden. Abhängig von Reaktionstemperatur und ‐ stöchiometrie werden durch Dehydrooligomerisierungen und P ‐ P ‐ Kupplungen beispiellose oligomere Ketten von Phosphanylboranen erhalten. btmsa = Bis(trimethylsilyl)acetylen. [ABSTRACT FROM AUTHOR]

The coordination chemistry of only Lewis‐base (LB)‐stabilized pnictogenylboranes EH2BH2⋅NMe3 (E=P, As) towards Tl(I) salts has been studied. The reaction of Tl[BArCl] (BArCl=[B(3,5‐C6H3Cl2)4]−) with the corresponding pnictogenylborane results in the formation of [Tl(EH2BH2⋅NMe3)][BArCl] (1 a: E=P; 1 b: E=As). Whereas the Tl ion in 1 a/b is monocoordinated, the exchange of the weakly coordinating anion (WCA) in the Tl(I) salt leads to the formation of a trigonal pyramidal coordination mode at the Tl atom by coordination of three equivalents of EH2BH2 ⋅ NMe3 in [Tl(EH2BH2 ⋅ NMe3)3][WCA] (2 a: E=P, WCA=TEFCl; 2 b: E=As, WCA=TEF) (TEF=[Al{OC(CF3)3}4]−, TEFCl=[Al{(OC(CF3)2(CCl3)}4]−). Furthermore, by using two equivalents of PH2BH2⋅NMe3, a Tl(I)‐mediated P−P coupling takes place in CH2Cl2 as solvent resulting in [Me3N⋅BH2PH2PHBH2⋅NMe3][WCA] (WCA=TEF, 3 a; BArCl, 3 b; TEFCl, 3 c). In contrast, for the arsenic derivatives 1 b and 2 b, no coupling reaction is observed. The underlying chemical processes are elucidated by quantum chemical computations. [ABSTRACT FROM AUTHOR]

Abstract: Muscular hyperactivity during handwriting, irregular and jerky scripts, as well as awkward and slowed pen movements are the cardinal symptoms of writer’s cramp. Accordingly, impaired kinematics and increased force have been reported in writer’s cramp. However, the relationship between these symptoms has rarely been investigated. In addition, measurements of finger forces have been restricted to the vertical pen pressure. In the present study, the pen of a graphic tablet was equipped with a force sensor matrix to measure also the grip force produced against the pen barrel despite highly variable pen grips of the patients. Kinematics of writing movements, vertical pen pressure, and grip force were compared in 27 patients with writer’s cramp and normal control writers during writing of a test sentence. As expected, all measures revealed a significantly worse writing performance in the patients compared to the control subjects. Exaggerated forces were more frequent than abnormal kinematics, and evidenced by prolonged movement times and reduced writing frequencies. Correlations were found neither between kinematics and force measures nor between the two forces. Interestingly, patients relaxed the grip force during short periods of non-writing by the same relative amount as control subjects. The finding of a large heterogeneity of performances patterns in writer’s cramp may reflect the variability of dystonic symptoms as well as the highly variable compensatory strategies of individual patients. Measurements of finger force and in particular of the grip force are valuable and important descriptors of individual impairment characteristics that are independent of writing kinematics. [Copyright &y& Elsevier]

Capillary electrophoresis (CE) was coupled to ICPMS in order to combine the good performance of this separation technique with the high sensitivity of the ICPMS for the analysis of plutonium and neptunium oxidation states. The combination of a fused-silica capillary with a Micro- Mist AR 30-I-FMO2 nebulizer and a Cinnabar small- volume cyclonic spray chamber yielded the best separation results. With this setup, it was possible to separate a model element mixture containing neptunium (NpO[SUB2,SUP+]), uranium (UO[SUB2,SUP2+]), lanthanum (La[SUP3+]), and thorium (Th[SUP4+]) in I M acetic acid. The same conditions were also suitable for the separation of various oxidation states of plutonium and neptunium in different aqueous samples. All separations were obtained within less than 15 mm. A detection limit of 50 ppb ≡ 2 × 10[SUP-7] (3-fold standard deviation of a blank) was achieved. To prove the negligible disturbance of the plutonium and neptunium redox equilibria during the CE separations, plutonium and neptunium speciation by CE-ICPMS in acidic solutions was compared with the results of UV/visible absorption spectros- copy and was found to be in good agreement. The CE- ICPMS system was also applied to study the reduction of Pu(V1) in a humic acid-containing groundwater at different pH values. [ABSTRACT FROM AUTHOR]

Space-based Radio Occultation (RO) experiments currently require the tracking of signals from the Global Navigation Satellite System (GNSS) by a Low-Earth-Orbit (LEO) satellite as the signals travel through different layers of the atmosphere. The orbit and clock solutions for the GNSS constellations affect these experiments in two ways: They are needed to obtain a zero-differencing GNSS-based orbit and clock solution for the LEO, and they enter directly the processing of each single radio occultation profile, where the orbit and clock information for the transmitter (GNSS satellite) and receiver (LEO) is required. In this work, we investigate how different GLONASS and GPS orbit and clock solutions affect the statistical properties of RO profiles by comparing our results with forward-modelled bending angle profiles obtained from the European Centre for Medium-Range Weather Forecasts (ECMWF) short-range forecasts. Given that GNSS orbits are relatively smooth, the focus will be on the effect of different transmitter clock data rates, and we tested the range from 1 to 30 seconds. The analysis is based on the reprocessing of Sentinel-6A data (four months in 2021, or about 110k occultations) and of a smaller sample of recent COSMIC-2/FORMOSAT-7 data (about 9k occultations). We find that at impacts heights above about 35 km GLONASS bending angles statistics markedly improve with the use of high-rate clock information. For GPS, not much is gained by using rates higher than 30 s, and the statistics are better for more recent GPS blocks. These results are likely the manifestation of the different short-timescale behaviour of the atomic clocks onboard the GPS and GLONASS constellations. [ABSTRACT FROM AUTHOR]

This study presents an exhaustive assessment of the Sentinel-6A Michael Freilich Radio Occultation (RO) data, focusing on the evaluation of bending angle products derived from the EUMETSAT-provided RO Non-Time Critical (RO-NTC) data collected between September and December 2021. This analysis confirms the satellite's capability to exceed its target of 770 quality checked bending angle profiles per day, with an availability rate of 99.9 %, demonstrating the robustness of the mission's operational performance. A detailed examination of the Signal-To-Noise Ratio (SNR) and phase noise indicates the high-quality nature of the data. The study also analyses the benefits of employing SNR-based signal cutoff strategies and L2 signal extrapolation in the troposphere, where it is more susceptible to SNR reductions. Furthermore, the paper details some processor enhancements, which led to improved bending angle statistics, particularly below 22 km altitude. Additionally, the analysis revealed terrestrial interference signals on the L2 frequency, confirming that they do not significantly compromise the Sentinel-6A RO data quality. The validation of the EUMETSAT processed Sentinel-6A RO-NTC data against the European Centre for Medium-Range Weather Forecasts (ECMWF) short-range forecasts and comparisons with Metop-B/C and EUMETSAT-processed SPIRE occultations, highlights the reduction in random error and modifications in the tropospheric bias structure, a result of the enhancements in data processing techniques. This comprehensive analysis confirms the high quality of the EUMETSAT Sentinel-6A bending angle products and underlines the satellite's contribution to the EUMETSAT legacy of precise and reliable radio occultation data for weather forecasting and climate research. [ABSTRACT FROM AUTHOR]

Earth observation from space provides a highly valuable basis for atmospheric and climate science, in particular also through climate benchmark data from suitable remote sensing techniques. Measurements by global navigation satellite system (GNSS) radio occultation (RO) qualify to produce such benchmark data records as they globally provide accurate and long-term stable datasets for essential climate variables (ECVs) such as temperature. This requires a rigorous processing of the raw RO measurements to ECVs, with narrow uncertainties. In order to fully exploit this potential, Wegener Center's Reference Occultation Processing System (rOPS) Level 1a (L1a) processing subsystem includes uncertainty estimation in both precise orbit determination (POD) and excess-phase profile derivation. Here we introduce the new rOPS L1a excess-phase processing, the first step in the RO profiles retrieval down to atmospheric profiles, which extracts the atmospheric excess phase from raw SI-traceable RO measurements. This excess-phase processing, for itself algorithmically concise, includes integrated quality control and uncertainty estimation, requiring a complex framework of various subsystems that we first introduce before describing the implementation of the core algorithms. The quality control and uncertainty estimation, computed per RO event, are supported by reliable forward-modeled excess-phase profiles based on the POD orbit arcs and collocated short-range forecast profiles of the European Centre for Medium-Range Weather Forecasts (ECMWF) Reanalysis (ERA5). The quality control removes or alternatively flags excess-phase profiles of insufficient or degraded quality. The uncertainty estimation accounts both for relevant random- and systematic-uncertainty components, and the resulting (total) uncertainty profiles serve as a starting point for the subsequent uncertainty propagation through the retrieval processing chain down to the atmospheric ECV profiles. We also evaluated the quality and reliability of the resulting excess-phase profiles based on Metop-A/B/C (Meteorological Operational) RO datasets for three 3-month periods in 2008, 2013, and 2020 by way of a sensitivity analysis for three representative atmospheric layers (tropo-, strato-, mesosphere), investigating consistency with ERA5-derived profiles, influences of different orbit and clock inputs, and consistency across the different Metop satellites. These consistencies range from centimeter to submillimeter levels, indicating that the new processing can provide highly accurate and robust excess-phase profiles. Furthermore, cross-evaluation and intercomparison with excess-phase data from the established data providers EUMETSAT (European Organisation for the Exploitation of Meteorological Satellites) and UCAR (University Corporation for Atmospheric Research) revealed subtle discrepancies but overall very close agreement, with larger differences compared to UCAR in the boundary layer. The new rOPS L1a processing can hence be considered capable of producing reliable long-term data records including uncertainty estimation for the benefit of climate applications. [ABSTRACT FROM AUTHOR]

Aggregates of interacting molecules can exhibit electronically excited states that are coherently delocalized over many molecules. This can lead to a strong enhancement of the fluorescence decay rate which is referred to as superradiance (SR). To date, the temperature dependence of SR is described by a 1/T law. Using an epitaxial dye layer and a Frenkel-exciton based model we provide both experimental and theoretical evidence that significant deviations from the 1/T behavior can occur for brick-wall-type aggregates of finite size leading even to a maximum of the SR at finite temperature. This is due to the presence of low energy excitations of weak or zero transition strength. These findings are relevant for designing light-emitting molecular materials. [ABSTRACT FROM AUTHOR]

The research and demonstration project, DEMO‐SPK, a model project under the German Mobility and Fuel Strategy (MFS), investigated the use of renewable kerosene at the Leipzig/Halle airport. Its primary goal was to examine and verify the behavior of blends consisting of several types of renewable kerosene and fossil JET A‐1, under the realistic supply conditions of a major airport. The project demonstrated that the supply chain for multiblend JET A‐1 was technically feasible and that the fuel could be used without requiring any changes in the normal operating procedures. The project also confirmed that the use of multiblend JET A‐1 resulted in a 30–60% reduction in particulate emissions for ground operations and a reduction in CO2 equivalents, compared with pure fossil JET A‐1. [ABSTRACT FROM AUTHOR]

Small amounts of the model molecule perylene-3,4,9,10-tetracarboxylic acid dianhydride (PTCDA) were vacuum deposited on epitaxial KCl films on Ag(100). The use of a low substrate temperature (20 K) during deposition hampered molecular diffusion resulting in isolated monomers on the surface. Fluorescence and fluorescence excitation spectroscopy performed on these monomers yielded highly resolved spectra with narrow lines corresponding to individual vibronic modes. This high resolution in our spectra is caused by a very small inhomogeneous broadening due to well-defined adsorption sites of the molecule on the substrate. Indeed, by polarization dependent fluorescence spectroscopy we show that the flat-lying molecules exhibit a preferred azimuthal orientation on the surface, the long molecular axis being oriented along the [011] or the equivalent [formula] direction of the substrate. Furthermore, the high resolution in the spectra allowed a detailed analysis of the vibronic modes. The vibrational modes of the adsorbed molecule are very similar to those of the free PTCDA molecule, but due to the presence of the substrate additional low energy modes which are relevant for the full understanding of the spectra couple to the transition. [ABSTRACT FROM AUTHOR]

The reactions of the phosphinoborane Ph2PBH2·NMe3 with Cu(I) halides [CuCl, CuBr, CuI] and [Cu(CH3CN)4BF4], respectively, were studied. Depending on the ratio of the reactants used, the former reaction allowed for the synthesis of eight neutral coordination compounds with the general formula [CunXn(Ph2PBH2·NMe3)m] (X = Cl, Br, I; n = 1, 2, 4, 5; m = 2, 4) (4–11). The latter reaction, however, led to the formation of the homoleptic complex [Cu(Ph2PBH2·NMe3)3][BF4] (13). The structures of the products 4–11 and 13 were compared to related complexes possessing the well‐known Ph3P ligand. All compounds were characterized by single crystal X‐ray structure analysis, multinuclear NMR spectroscopy, IR spectroscopy and mass spectrometry. [ABSTRACT FROM AUTHOR]

High‐molar‐mass poly(alkylphosphinoboranes) are currently not accessible by conventional metal‐catalyzed dehydropolymerization. However, the mild thermolysis of a Lewis base stabilized phosphinoborane is an alternative metal‐free approach. In their Communication on page 13782 ff., M. Scheer, I. Manners, and co‐workers describe their successful synthesis of poly(tert‐butylphosphinoborane) by this promising strategy. [ABSTRACT FROM AUTHOR]

Poly(alkylphosphanylborane) mit hohen Molekülmassen sind derzeit auf herkömmliche Weise durch metallkatalysierte Dehydropolymerisation nicht zugänglich, als metallfreie Alternative bietet sich aber die milde Thermolyse eines Lewis ‐ Base ‐ stabilisierten Phosphanylborans an. In der Zuschrift auf S. 13986 ff. beschreiben M. Scheer, I. Manners et al. die erfolgreiche Synthese von Poly(tert ‐ butylphosphanylboran) nach dieser vielversprechenden Strategie. [ABSTRACT FROM AUTHOR]

In this work, a dedicated campaign by MetOp-A satellite is conducted to monitor the ionosphere based on radio-occultation (RO) measurements provided by the onboard GNSS (Global Navigation Satellite System) Receiver for Atmospheric Sounding (GRAS). The main goal is to analyze the capabilities of the collected data to represent the bending angle and scintillation profiles of the ionosphere. We compare the MetOp-A products with those generated by other RO missions and explore the spatial/temporal distributions sensed by the MetOp-A campaign. Validation of dual frequency bending angles at the RO tangent points, S4 index, and Rate of the Total electron content Index (ROTI) is performed against independent products from Fengyun-3D and FORMOSAT-7/COSMIC-2 satellites. Our main findings constitute the following: (1) bending angle profiles from MetOp-A agree well with Fengyun-3D measurements; (2) bending angle distributions show a typical S-shape variation along the altitudes; (3) signatures of the sporadic E-layer and equatorial ionization anomaly crests are observed by the bending angles; (4) sharp transitions are observed in the bending angle profiles above ~200 km due to the transition of the daytime/nighttime in addition to the transition of the bottom-side/top-side; and (5) sporadic E-layer signatures are observed in the S4 index distributions by MetOp-A and FORMOSAT-7/COSMIC-2, with expected differences in magnitudes between the GPS (Global Positioning System) L1 and L2 frequencies. [ABSTRACT FROM AUTHOR]

Earth observation from space provides a highly valuable basis for atmospheric and climate science, in particular also through climate benchmark data from suitable remote sensing techniques. Measurements by Global Navigation Satellite System (GNSS) radio occultation (RO) qualify to produce such benchmark data records as they globally provide accurate and long-term stable datasets for essential climate variables (ECVs) such as temperature. This requires a rigorous processing from the raw RO measurements to ECVs, with narrow uncertainties. In order to fully exploit this potential, Wegener Center's Reference Occultation Processing System (rOPS) Level 1a (L1a) processing subsystem includes uncertainty estimation in both precise orbit determination (POD) and excess phase profile derivation. Here we introduce the new rOPS L1a excess phase processing, the first step in the RO profiles retrieval down to atmospheric profiles, which extracts the atmospheric excess phase from raw SI-traceable RO measurements. This excess phase processing, for itself algorithmically concise, includes integrated quality control and uncertainty estimation, which requires a complex framework of various subsystems that we first introduce before describing the implementation of the core algorithms. The quality control and uncertainty estimation, computed per RO event, are supported by reliable forward-modeled excess phase profiles based on the POD orbit arcs and collocated short-range forecast profiles of the European Reanalysis ERA5. The quality control removes or alternatively flags excess phase profiles of insufficient or degraded quality. The uncertainty estimation accounts both for relevant random and systematic uncertainty components and the resulting (total) uncertainty profiles serve as starting point for the subsequent uncertainty propagation through the retrieval processing chain down to the atmospheric ECV profiles. We also evaluated the quality and reliability of the resulting excess phase profiles based on Metop-A/B/C RO datasets for three 3-month periods in 2008, 2013, and 2020 by way of a sensitivity analysis for three representative atmospheric layers (tropo-, strato-, mesosphere), investigating consistency with ERA5-derived profiles, influences of different orbit and clock inputs and consistency across the different Metop satellites. These consistencies range from centimeter to submillimeter levels, indicating that the new processing can provide highly accurate and robust excess phase profiles. Furthermore, cross-validation and inter-comparison with excess phase data from the established data providers EUMETSAT and UCAR revealed subtle discrepancies but overall very close agreement, with larger differences against UCAR in the boundary layer. The new rOPS L1a processing can hence be considered capable to produce reliable long-term data records including uncertainty estimation for the benefit of climate applications. [ABSTRACT FROM AUTHOR]

The radio occultation (RO) measurements of the Global Navigation Satellite System's (GNSS's) signals onboard a Low Earth Orbiting (LEO) satellite enable the computation of the vertical electron density profile from the LEO satellite's orbit height down to the Earth's surface. The ionospheric extension experiment performed by the GNSS Receiver for Atmospheric Sounding (GRAS) receiver on board MetOp-A provides opportunities for ionospheric sounding but with the RO measurements only taken with an impact parameter height below 600 and 300 km within two different experiments, although MetOp-A was flying at an orbit height of about 800 km. Here, we present a model-assisted RO inversion technique for electron density retrieval from such kind of truncated data. The topside ionosphere and plasmasphere above the LEO orbit height are modelled by a Chapman layer function superposed with an exponential decay function representing the plasmasphere. Our investigation shows that the model-assisted technique is stable and robust and can successfully be used to retrieve the electron density values up to the LEO height from the truncated MetOp-A data, in particular when observations are available until 600 km. Moreover, this model-assisted technique is also successful with the availability of a small number of observations of the topside above the peak density height. For observations available only up to 300 km, the accuracy of the retrieved profile is comparable to the one obtained by the data truncated at a 600 km height only when the peak electron density lies below the 250 km altitude level. [ABSTRACT FROM AUTHOR]

A simple method to access borylphosphonium iodides [RH2P-BH2 ·NMe3]I ( 1a: R = Me; 1b: R = Et; 1c: R = nPr) by the addition of iodoalkanes to PH2-BH2 ·NMe3 was developed. Complexes 1a- c were characterized by multinuclear NMR spectroscopy, and 1a and 1b additionally by single-crystal X-ray diffraction. It was possible to synthesize the Lewis-base-stabilized organosubstituted phosphanylborane MePH-BH2 ·NMe3 ( 2) from [MePH2-BH2 ·NMe3]I ( 1a). Thermolysis of 2 generated a soluble, low-molecular-mass poly(alkylphosphinoborane) consisting of at least 40 repeat units, as identified by ESI-MS. These results are promising for the future preparation of a wide range of Lewis-base-stabilized phosphanylboranes, which are of interest as precursors to poly[(alkylphosphino)boranes] and are otherwise difficult to access by conventional metal-catalyzed methods. [ABSTRACT FROM AUTHOR]

Abstract: Although the formation of tetravalent plutonium (Pu(IV)) polymers with natural organic matter was previously observed by spectroscopy, there is no quantitative evidence of such reaction in batch experiments. In the present study, Pu(IV) interaction with humic acid (HA) was investigated at pH 1.8, 2.5 and 3, as a function of HA concentration and for Pu total concentration equal to 6×10−8 M. The finally measured Pu(IV) concentrations ([Pu(IV)] eq ) are below Pu(IV) solubility limit. Pu(IV)–HA interaction can be explained by the complexation of Pu(IV) monomers by HA up to [Pu(IV)] eq ∼10−8 M. However, the slope of the log–log Pu(IV)–HA binding isotherm changes from ∼0.7 to ∼3.5 for higher [Pu(IV)] eq than ∼10−8 M and at any pH. This result suggests the stabilization of hydrolyzed polymeric Pu(IV) species by HA, with a 4:1 Pu:HA stoichiometry. This confirms, for the first time, previous observations made by spectroscopy in concentrated systems. The humic-ion binding model, Model VII, was introduced into the geochemical speciation program PHREEQC and was used to simulate Pu(IV) monomers binding to HA. The simulations are consistent with other tetravalent actinides–HA binding data from literature. The stabilization of a Pu tetramer by HA was proposed to illustrate the present experimental results for [Pu(IV)] eq >10−8 M. Predictive simulations of Pu(IV) apparent solubility due to HA show that the chosen Pu(IV)-polymer has no impact for pH>4. However, the comparison between these predictions and recent spectroscopic results suggest that more hydrolyzed polymeric Pu(IV) species can be stabilized by HA at pH>4. Polymeric Pu(IV)–HA species might significantly enhance Pu(IV) apparent solubility due to humics, which support a colloid-facilitated transport of this low solubility element. [Copyright &y& Elsevier]

The speciation of redox sensitive trivalent actinides Pu(III), Np(III), and U(III) has been studied in aqueous solution. The redox preparation, stabilization, and speciation of these trivalent actinides in aqueous systems are discussed here. The reductants investigated were rongalite, hydroxylamine hydrochloride, and acetohydroxamic acid and the An(III) species have been characterized by UV-Vis and XANES spectroscopy. The results show that the effectiveness of stabilization decreases generally in the order Pu(III) > Np(III) > U(III) and that the effectiveness of each reducing agent depends on the experimental conditions. More than 80 % of Pu(III) aquo species have been stabilized up to pH 5.5, whereas the Np(III) aquo ion could be stabilized in a pH range 0-2.5, and U(III) aquo ion is sufficiently stable at pH 1.0 and below over time periods suitable for experiments. However, this study gives a basis for the characterisation of the trivalent lighter actinides involved in complexation, sorption, and solid formation reactions in the future. [ABSTRACT FROM AUTHOR]

The aim of the present study was to determine whether the motor process of handwriting is influenced by a circadian rhythm. Nine healthy young male subjects underwent a 40-h sleep deprivation protocol under constant routine conditions. Starting at 09:00 hours, subjects performed every 3 h two handwriting tasks of different complexity. Handwriting performance was evaluated by writing speed, writing fluency and script size. The frequency of handwriting, as a measure of movement speed, revealed a circadian rhythm, validated by harmonic regression, with a slowing at the time of the onset of melatonin secretion (22:17 hours) and a trough in the very early morning at around 03:30 hours. In the temporal variability of handwriting an effect of task complexity was suggested in the direction of circadian variations in parallel with speed only for the sentence. Despite deficits of speed and temporal variability, writing fluency did not change significantly across sessions indicating that the basic automation of handwriting was preserved at any time. On the second day, daytime levels of the kinematics of handwriting did not reflect impaired performance after sleep deprivation. Our results show for the first time a clear circadian rhythm for the production of handwriting. [ABSTRACT FROM AUTHOR]

Abstract: X-ray absorption near edge structure (XANES) spectroscopy for in situ metal valence determination has become a powerful analytical tool in heterogeneous systems. This is in part because it is applicable without prior separation procedures. For some systems, however, determining the oxidation state from XANES spectra is not straightforward and caution must be used. We show that the analysis of L3,2 edge EXAFS (extended X-ray absorption fine structure) spectra is better suited to distinguish between Np(IV) and Np(V) than from their XANES spectra. Whereas evidence for the oxidation of Np(IV) in solution samples from their Np L3 XANES is unclear, their EXAFS data unequivocally reveals Np(V) formation in the solutions. [Copyright &y& Elsevier]

Objective: Anticipatory grip force adjustments to movement-induced load fluctuations of a hand-held object suggest that motion planning is based on an internal forward model of both the external object properties and the dynamics of the own motor apparatus. However, the central nervous system also refers to real time sensory feedback from the grasping digits in order to achieve a highly economical coupling between grip force and the actual loading requirements.Methods: We analyzed grip force control during vertical point-to-point arm movements with a hand-held instrumented object in 9 patients with moderately impaired tactile sensibility of the grasping digits due to chronic median nerve compression (n=3), axonal (n=3) and demyelinating sensory polyneuropathy (n=3) in comparison to 9 healthy age- and sex-matched control subjects. Point-to-point arm movements started and ended with the object being held stationary at rest. Load force changes arose from inertial loads related to the movement. A maximum of load force occurred early in upward and near the end of downward movements.Results: Compared to healthy controls, patients with impaired manual sensibility generated similar static grip forces during stationary holding of the object and similar force ratios between maximum grip and load force. These findings reflect effective grip force scaling in relation to the movement-induced loads despite reduced afferent feedback from the grasping digits. For both groups the maxima of grip and load force coincided very closely in time, indicating that the temporal regulation of the grip force profile with the load profile was processed with a similar high precision. In addition, linear regression analyses between grip and load forces during movement-related load increase and load decrease phases revealed a similar precise temporo-spatial coupling between grip and load forces for patients and controls.Conclusions: Our results suggest that the precise and anticipatory adjustment of the grip force profile to the load force profile arising from voluntary arm movements with a hand-held object is centrally mediated and less under sensory feedback control. As suggested by previous investigations, the efficient scaling of the grip force magnitude in relation to the movement-induced loads may be intact when deficits of tactile sensibility from the grasping fingers are moderate. [Copyright &y& Elsevier]

After successful launch in November 2018 and successful commissioning of Metop-C, all three satellites of the EUMETSAT Polar System (EPS) are in orbit together and operational. EPS is part of the Initial Joint Polar System (IJPS) with the United States (NOAA) and provides the service in the midmorning orbit. The Metop satellites carry a mission payload of sounding and imaging instruments, which allow provision of support to operational meteorology and climate monitoring, which are the main mission objectives for EPS. Applications include numerical weather prediction, atmospheric composition monitoring, and marine meteorology. Climate monitoring is supported through the generation of long time series through the program duration of 20+ years. The payload was developed and contributed by partners, including NOAA, CNES, and ESA. EUMETSAT and ESA developed the space segment in cooperation. The system has proven its value since the first satellite Metop-A, with enhanced products at high reliability for atmospheric sounding, delivered a very strong positive impact on NWP and results beyond expectations for atmospheric composition and chemistry applications. Having multiple satellites in orbit—now three—has enabled enhanced and additional products with increased impact, like atmospheric motion vector products at latitudes not accessible to geostationary observations or increased probability of radio occultations and hence atmospheric soundings with the Global Navigation Satellite System (GNSS) Radio-Occultation Atmospheric Sounder (GRAS) instruments. The paper gives an overview of the system and the embarked payload and discusses the benefits of generated products for applications and services. The conclusions point to the follow-on system, currently under development and assuring continuity for another 20+ years. [ABSTRACT FROM AUTHOR]

Introduction: There is limited data in the scientific literature using quantitative methods to assess response of golfer's cramp to intervention. The objective of this pilot study was to use quantitative measures to study the effect of propranolol and looking at the hole when putting.Methods: 14 golfers completed 50 10' putts (10 each x 5 conditions): two-handed looking at the ball, right hand only looking at the ball, two-handed looking at the hole, then following a single 10 mg oral dose of propranolol two-handed and right hand only putts looking at the ball. Quantitative measurements of putter movement and surface EMG to assess wrist muscle co-contraction were measured.Results: Based on video review of the putting, five golfers with dystonic golfer's cramp and nine with non-dystonic yips were compared. Those with dystonic golfer's cramp had more putts with the yips and yips with co-contraction when two-handed putting looking at the ball, no increase when putting right hand only, less smoothness of putter movement, and all of these improved following propranolol and when looking at the hole. The non-dystonic group had an increase in yipped putts and yipped putts with co-contraction putting right hand only and no improvement with either intervention.Conclusion: Yipped putts with co-contraction, right hand only putting, and smoothness of putter movement differed between dystonic golfer's cramp and non-dystonic yips. Propranolol and looking at the hole only improved dystonic golfer's cramp putting. This is the first pilot study of oral medication treatment for this task-specific dystonia. [ABSTRACT FROM AUTHOR]

Attunement to visual information has been suggested to mediate the performance advantage associated with adopting an external focus of attention (e.g., Al-Abood, Bennett, Moreno Hernandez, Ashford, & Davids, 2002; Magill, 1998). We tested this hypothesis by examining the extent to which online visual information underpins the external focus advantage. The study examined skilled golfers on a putting task under one of three attentional focus conditions: control (no instructions), irrelevant (tone counting), and external (movement effect focus), with either full or occluded vision. In addition to task performance, the effect of attentional focus and vision on between-trial movement variability was examined. We found a significant advantage for an external focus of attention in the absence of vision. The results of the movement variability analysis further indicated that external focus was not mediated by the online use of vision. We discuss these findings in the context of traditional cognitive perspectives to external focus effects. [ABSTRACT FROM AUTHOR]

Attunement to visual information has been suggested to mediate the performance advantage associated with adopting an external focus of attention (e.g., Al-Abood, Bennett, Moreno Hernandez, Ashford, & Davids, 2002; Magill, 1998). We tested this hypothesis by examining the extent to which online visual information underpins the external focus advantage. The study examined skilled golfers on a putting task under one of three attentional focus conditions: control (no instructions), irrelevant (tone counting), and external (movement effect focus), with either full or occluded vision. In addition to task performance, the effect of attentional focus and vision on between-trial movement variability was examined. We found a significant advantage for an external focus of attention in the absence of vision. The results of the movement variability analysis further indicated that external focus was not mediated by the online use of vision. We discuss these findings in the context of traditional cognitive perspectives to external focus effects. [ABSTRACT FROM AUTHOR]

Purpose: To determine whether quantitative methods could separate golfers with a possible dystonic cause of the "yips" from those that appear to be nondystonic. Methods: Twenty-seven golfers completed 10 two-handed and 10 right hand–only putts. Surface EMG assessed forearm muscle co-contraction and motion detectors monitored wrist and putter movements. Based on a videotape review, golfers were grouped into those with yips of dystonic etiology, those with the yips nondystonic, and those with no yips. Results: On video review of two-handed putting, five golfers had yips that appeared to be dystonic, nine had yips that did not appear to be dystonic, and 13 had no yips. During two-handed putting co-occurrence of a yipped putt and wrist flexor/extensor and/or pronator/supinator co-contraction was significantly more frequent in those with dystonic yips. The dystonic group had no increase in the number of yipped putts or yips with co-contraction when putting right hand only, whereas the nondystonic group had significantly more yipped putts and more yipped putts with co-contraction with right hand only. Conclusions: Quantitative methods were identified that appear to identify golfers with a dystonic etiology for the yips. It is not just the frequency of yips nor just specific motion patterns alone, rather it is also a combination of yips with co-occurring co-contraction when putting with two hands, and then right hand only, that distinguished this possible etiology. Despite being a small study, identifying a dystonic pattern, even in a nonpressure indoor setting, may aid in assessment and possible monitoring of treatment. [ABSTRACT FROM AUTHOR]

Scale formation processes in the surface installations of geothermal power plants may have a negative effect on power plant performance. In addition, scales formed within the geothermal water circuit frequently accumulate natural radionuclides. Consequently, scale formation may lead to radiation dose rates, which are of radiological concern, and deposits, which may have to be disposed as radioactive waste. In order to minimize these problems and to foster geothermal power plant availability, it is of major interest to understand scale formation processes and to develop methods for their inhibition. One important pre-requisite towards this goal is a sound mineralogical and geochemical characterization of the formed material. Geothermal brines at sites in the Upper Rhine Graben are in general highly mineralized and become, upon cooling in the heat exchanger, supersaturated with respect to sulfate solid-solutions, e.g. (Ba,Sr)SO 4 , and other mineral phases. Some geothermal power plants very successfully tested the application of sulfate scaling inhibitors. Here we present mineralogical analyses of scale samples from geothermal power plants in the Upper Rhine Valley deposited in absence and presence of sulfate scaling inhibitors. Solid samples are investigated using wet-chemistry (after digestion), XRPD, SEM-EDX, XPS, EA-IRMS, Raman spectroscopy, and XANES (for explanation of abbreviations, see main text). Samples of scales deposited in the absence of a sulfate scaling inhibitor mainly consist of two phases. The largest part is made up of a barite type (Ba,Sr,Ca)SO 4 solid-solution. Traces of Ra occurring in the scaling are assumed to be incorporated in the barite type solid solution. Further minor phases are sulfide phases, either an X-ray amorphous nano-particulate phase or galena (PbS). Since the application of the sulfate inhibitor, sulfate minerals are no longer detectable in the scale samples. Subsequent scalings are Pb-dominated and consist mainly of galena (PbS), elemental lead (Pb), arsenic (As) and antimony (Sb). As and Sb are likely present as a nanocrystalline intermetallic mixed compound ((Sb, As) or Pb 3 (Sb,As) 2 S 3 ). The absence of barite-type minerals demonstrates the success of the application of the sulfate inhibitor. The precipitation of elemental Pb, As, and Sb, which are more noble than iron, may enhance the corrosion of mild steel pipes in the geothermal water circuit. Elution tests and oxidation of the scalings upon storage at atmospheric conditions demonstrate that proper disposal of the toxic heavy metal and metalloid containing scalings may be challenging. [ABSTRACT FROM AUTHOR]

Neptunium (Np) uptake on illite is investigated in 1 and 3.2 molal (m) NaCl solutions under inert (Ar) atmosphere for 4 < pH m < 10 (pH m = −log m H + ) and 5 × 10 −8 < [Np(V)] tot < 3 × 10 −4 M. In agreement with a previous study in 0.1 m NaCl solutions (Marsac et al., 2015a), Np(V) is the prevailing oxidation state in the aqueous solution, but Np uptake by illite is affected by surface induced reduction. The extent of Np(V) reduction to Np(IV) follows the measured redox potential (or the pe = −log a e− ), which is influenced by the introduced Np(V) amount, because of the low redox capacity of the illite. The presence of Np(IV) on the solid phase is verified by X-ray Absorption Near Edge Spectroscopy (XANES). We can conclude that Np uptake by illite is not significantly affected by the variation of m NaCl from 0.1 to 3.2 m and thus is in agreement with reports on tetravalent actinide and Np(V) sorption to clays at high ionic strength. The combination of (i) the two site protolysis non-electrostatic surface complexation and cation exchange model, (ii) the specific ion interaction theory to calculate activity coefficients for dissolved species and (iii) by accounting for redox equilibria and the stability of surface Np species, the overall Np uptake by illite can be simulated as a function of pH m , pe and m NaCl using a single set of parameters. The present experimental and modeling results are particularly important in the context of deep geological nuclear waste disposal since many sedimentary rocks or clay formations that are deemed suitable for this purpose exhibit highly saline porewaters. [ABSTRACT FROM AUTHOR]