A survey of multi-fingered robot hands: issues and grasping achievements

Recently a substantial amount of research has been done in the field of dextrous manipulation and hand manoeuvres. The main concern has been how to control robot hands so that they can execute manipulation tasks with the same dexterity and intuition as human hands. This paper surveys multi-fingered robot hand research and development topics which include robot hand design, object force distribution and control, grip transform, grasp stability and its synthesis, grasp stiffness and compliance motion and robot arm-hand coordination. Three main topics are presented in this article. The first is an introduction to the subject. The second concentrates on examples of mechanical manipulators used in research and the methods employed to control them. The third presents work which has been done on the field of object manipulation.

Bayesian design and conduct of phase II single-arm clinical trials with binary outcomes: a tutorial

The aim of phase II single-arm clinical trials of a new drug is to determine whether it has sufficient promising activity to warrant its further development. For the last several years Bayesian statistical methods have been proposed and used. Bayesian approaches are ideal for earlier phase trials as they take into account information that accrues during a trial. Predictive probabilities are then updated and so become more accurate as the trial progresses. Suitable priors can act as pseudo samples, which make small sample clinical trials more informative. Thus patients have better chances to receive better treatments. The goal of this paper is to provide a tutorial for statisticians who use Bayesian methods for the first time or investigators who have some statistical background. In addition, real data from three clinical trials are presented as examples to illustrate how to conduct a Bayesian approach for phase II single-arm clinical trials with binary outcomes.

Solid-state interconversions of coordination networks and hydrogen-bonded salts

Thermal or chemical treatment of crystalline 4,4-bipyridinium salts of [MCl4]2- (M=Co, Zn, Fe, or Pt) leads to HCl loss and formation of coordination network solids [{MCl2(4,4-bipy)}n]. For M=Co, Zn, and Fe, these solids can also be prepared by mechanochemical means. Their exposure to HCl vapor or the mechanochemical reaction of metal dichlorides with [4,4-H2bipy]Cl2 gives [4,4-H2bipy]2+ salts of [CoCl4]2-, [ZnCl4]2-, and, for the first time, [FeCl4]2-.

Interaction of 2-(arylazo)phenols with rhodium. Usual coordination vs. C-H and C-C activation

Reaction of 2-(2'-hydroxyphenylazo)phenol with [Rh(PPh3)(3)Cl] in refluxing benzene in presence of triethylamine afforded a red complex in which the ligand is coordinated to rhodium as a tridentate O,N,O-donor. However, similar reaction of [Rh(PPh3)(3)Cl] with 2-(2'carboxyphenylazo)-4-methylphenol yielded two complexes, viz. a blue one and a green one. In both the complexes the ligand is coordinated as C,N,O-donor. However, in the blue complex orthometallation takes place from the ortho-carbon atom, which bears -COOH group via decarboxylation and in green one orthometallation occurs from the other ortho-carbon. Structures of all the three complexes were determined by X-ray crystallography. In all the three complexes rhodium is sharing the equatorial plane with the tridentate ligand and a chloride, and the two triphenylphosphines are axially disposed. All of the complexes show intense MLCT transitions in the visible region. Cyclic voltammetry on these complexes shows a Rh(III)-Rh(IV) oxidation on the positive side of SCE and a reduction of the coordinated azophenolate ligand on the negative side. (c) 2006 Elsevier B.V. All rights reserved.

Construction of coordination polymers of cadmium(II) with mixed hexamethylenetetramine and terephthalate or thiocyanate ligands

Three new polymeric complexes [Cd(hmt)(SCN)(2)(H2O)(2)](n) (1), [Cd-3(mu(2)-hmt)(2)(SCN)(6)(H2O)(2)](n) (2), and [Cd-2(hmt)(2)(tP)(2)(H2O)(6)](n) (3) [hmt = hexamethylenetetramine, tp = terephthalate] have been synthesized and characterized by single crystal X-ray diffraction. Both the compounds 1 and 2 are 1-D polymers where Cd units are linked by double end-to-end thiocyanate bridges but in 2 the chain is wider containing three cadmium atoms instead of one as found in 1. In both compounds the coordination environment around cadmium atom is distorted octahedral. Compound 3 is a three-dimensional polymer having water-filled microporous channels. Both tp and brut are mu(2)-bridged. One of the acid groups of tp is coordinated in chelating bidentate and the other in monodentate fashion. Half of its Cd atoms are hexa-coordinated and the rest are hepta-coordinated. Thermogravimetric analysis and X-ray diffraction study of 3 show that its framework remains intact upon removal of water molecules. The flexibility of coordination number around cadmium atoms (six or seven) probably plays an important role in establishing the rigidity of the framework. (C) 2003 Elsevier Ltd. All rights reserved.

Zinc(II) mediated synthesis of an N-substituted 2-(2-pyridyl)imidazole from a 1,2-diketone and 2-(aminomethyl)pyridine and its ligational behaviour

Reaction of anhydrous ZnCl2 with the 1:2 condensate (L) of benzil and 2-(aminomethyl)pyridine in methanol gives monomeric ZnL'Cl-2 (1) where L' is 2-[(4,5-diphenyl-2-pyridin-2-yl-1H-imidazol-1-yl)-methyl]pyridine. In the X-ray crystal structure, 1 is found to contain tetrahedral zinc with an N2Cl2 coordination sphere and the N-substituent methylpyridine fragment hanging as a free arm. A tentative mechanism is proposed for the zinc mediated conversion of L-->L'. Demetallation of 1 by the action of aqueous NaOH yields L' in the free state. When L' is reacted with Zn(ClO4)(2).6H(2)O in a 1:2 molar proportion, [Zn(L')(2)](n)(ClO4)(2n).(H2O)(n/2).(CH2Cl2)(n/2) (2) is obtained. The zinc atom in 2, as revealed by X-ray crystallography, has a trigonal bipyramidal N-5 coordination sphere. There are two independent ligands in the asymmetric unit of 2. One of them bonds only to one zinc atom in a bidentate mode with the N-substituent methylpyridine hanging free while the other ligand binds to two different zinc atoms in a tridentate fashion, employing the N-substituent methylpyridine nitrogen atom to form the polymeric one-dimensional chain cation.

Syntheses and crystal structures of two new coordination polymers of Cd(II) using organic spacer and inorganic-bridging ligands

Two new cadmium (II) complexes [Cd(hmt)(dca)(2)] (n) (1) and [Cd-3(hmt)(2)(SeCN)(6)(H2O)(2)] (n) (2) (hmt=hexamethylenetetramine, dca=dicyanamide) have been synthesized and characterized by X-ray single-crystal analysis. The complex 1 is a 2D rectangular grid of octahedral cadmium (II) with CdN6 chromophore where cadmium centers are doubly bridged by dicyanamide and hmt along a-axis, which are interlinked by dicyanamide running along c-axis. Whereas, complex 2 is a 1D chain of octahedral cadmium (II) with a three-leg ladder topology running along a-axis. The Cd(II) centers are doubly bridged through SeCN (infinite rail) along a-axis and singly bridged by hmt (two-step rung) along c-axis, having cadmium centers with CdSe2N3O and CdSe2N4 chromophores. The adjacent chains through H-bonding between coordinated water and hmt, and (SeSe)-Se-... interaction are extended to 2D supramolecular architecture.

Bis- and tris-(methylphosphonic) acid derivatives of a 14-membered tetraazamacrocycle containing pyridine: synthesis, protonation and complexation studies

Two N-methylphosphonic acid derivatives of a 14-membered tetraazamacrocycle containing pyridine have been synthesized, H4L1 and H6L2. The protonation constants of these compounds and the stability constants of complexes of both ligands with Ni2+, Cu2+ and Zn2+ were determined by potentiometric methods at 298 K and ionic strength 0.10 mol dm(-3) in NMe4NO3. The high overall basicity of both compounds is ascribed to the presence of the phosphonate arms. H-1 and P-31 NMR spectroscopic titrations were performed to elucidate the sequence of protonation, which were complemented by conformational analysis studies. The complexes of these ligands have stability constants of the order of or higher than those formed with ligands having the same macrocyclic backbone but acetate arms. At pH = 7 the highest pM values were found for solutions containing the compound with three acetate groups, followed immediately by those of H6L2, however, as expected, the increasing pH favours the complexes of ligands containing phosphonate groups. The single-crystal structure of Na-2[Cu(HL1)]NO3.8H(2)O has shown that the coordination geometry around the copper atom is a distorted square pyramid. Three nitrogen atoms of the macrocyclic backbone and one oxygen atom from one methylphosphonate arm define the basal plane, and the apical coordination is accomplished via the nitrogen atom trans to the pyridine ring of the macrocycle. To achieve this geometric arrangement, the macrocycle adopts a folded conformation. This structure seems consistent with Uv-vis-NIR spectroscopy for the Ni2+ and the Cu2+ complexes and with the EPR for the latter.

The coordination chemistry of 1,2,4-triazinyl bipyridines with lanthanide(III) elements - implications for the partitioning of americium(III)

It has been established that 6-(5,6-dialkyl-1,2,4-triazin-3-yl)-2,2'-bipyridines (R,hemi-BTPs) have properties which are intermediate between those of the terpyridines and the bis(1,2,4-triazin-3-yl)pyridines (BTPs). However, they resemble the terpyridines much more closely than the BTPs. It has been shown that Et, hemi-BTP when dissolved in TPH-a dodecane-like solvent-is a selective reagent for the separation of americium(III) from europium(III). Solution NMR in acetonitrile largely confirmed the crystallographic results. There was no evidence for a 1 : 3 complex cation, or for significant differences between metal(III)-N distances for the pyridine and 1,2,4-triazine rings. Intramolecular hydrogen bonding plays a crucial role in the formation of metal coordination spheres, which explains the differences between the terpyridyl, R,hemi-BTPs and the BTPs. Protonation of the R,hemi-BTPs facilitates a conformational change which is necessary for complexation.

Extraction and coordination studies of the unexplored bifunctional ligand carbamoyl methyl sulfoxide (CMSO) with uranium(VI) and cerium(III) nitrates. Synthesis and structures of [UO2(NO3)(2)((PhSOCH2CONBu2)-Bu-i)] and [Ce(NO3)(3)(PhSOCH2CONBu2)(2)]

The bifunctional carbamoyl methyl sulfoxide ligands, PhCH2SOCH2CONHPh (L-1), PhCH2SOCH2CONHCH2Ph (L-2), (PhSOCH2CONPr2)-Pr-i (L-3), PhSOCH2CONBu2 (L-4), (PhSOCH2CONBu2)-Bu-i (L-5) and PhSOCH2CON(C8H17)(2) (L-6) have been synthesized and characterized by spectroscopic methods. The selected coordination chemistry of L-1, L-3, L-4 and L-5 with [UO2(NO3)(2)] and [Ce(NO3)(3)] has been evaluated. The structures of the compounds [UO2(NO3)(2)((PhSOCH2CONBu2)-Bu-i)] (10) and [Ce(NO3)(3)(PhSOCH2CONBu2)(2)] (12) have been determined by single crystal X-ray diffraction methods. Preliminary extraction studies of ligand L-6 with U(VI), Pu(IV) and Am(III) in tracer level showed an appreciable extraction for U(VI) and Pu(IV) in up to 10 M HNO3 but not for Am(III). Thermal studies on compounds 8 and 10 in air revealed that the ligands can be destroyed completely on incineration. The electron spray mass spectra of compounds 8 and 10 in acetone show that extensive ligand distribution reactions occur in solution to give a mixture of products with ligand to metal ratios of 1 : 1 and 2 : 1. However, 10 retains its solid state structure in CH2Cl2.

Coordination and separation studies of the uranyl ion with iso-butyramide based ligands: Synthesis and structures of [UO2(NO3)(2)((C3H7CON)-C-i{(C4H9)-C-i}(2))(2)] and [UO2(C6H5COCHCOC6H5)(2)((C3H7CON)-C-i{(C3H7)-C-i}(2))]

The coordination chemistry of iso-butyramide based ligands such as: (C3H7CON)-C-i((C3H7)-C-i)(2), (C3H7CON)-C-i(C4H9)(2) and (C3H7CON)-C-i((C4H9)-C-i)(2) with [UO2(NO3)(2) center dot 6H(2)O], [UO2(OO)(2) center dot 2H(2)O] {where OO = C4H3SCOCHCCCF3 (TTA), C6H5COCHCOCF3 (BTA) and C6H5COCHCOC6H5 (DBM)), [Th(NO3)(4) center dot 6H(2)O] and [La(NO3)(3) center dot 6H(2)O] has been evaluated. Structures for the compounds [UO2(NO3)(2)CC3H7CON{(C4H9)-C-i}(2))(2)] and [UO2(C6H5COCHCOC6H5)(2)((C3H7CON)-C-i{(C3H7)-C-i)(2))] have been determined by single crystal X-ray diffraction methods. Preliminary separation studies from nitric acid medium using the amide (C3H7CON)-C-i((C4H9)-C-i)(2) with U(VI), Th(IV) and La(Ill) ions showed the selective precipitation of uranyl ion from the mixture. Thermal study of the compound [UO2(NO3)(2)((C3H7CON)-C-i((C4H9)-C-i)(2))(2)] in air revealed that the ligands can be destroyed completely on incineration. (C) 2008 Elsevier Ltd. All rights reserved.

Coordination and extraction studies of an unexplored bi-functional ligand, carbamoyl methyl pyrazole (CMPz) with uranium(VI), lanthanum(III) and cerium(III) nitrates

The bi-functional carbamoyl methyl pyrazole ligands, C5H7N2CH2CONBu2 (L-1), (C5H7N2CH2CONBu2)-Bu-i (L-2), C3H3N2CH2CONBu2 (L-3), (C3H3N2CH2CONBu2)-Bu-i (L-4) and C5H7N2CH2CON(C8H17)(2) (L-5) were synthesized and characterized by spectroscopic and elemental analysis methods. The selected coordination chemistry of L-1 to L-4 with [UO2(NO3)(2)center dot 6H(2)O], [La(NO3)(3)center dot 6H(2)O] and [Ce(NO3)(3)center dot 6H(2)O] has been evaluated. Structures for the compounds [UO2(NO3)(2) C5H7N2CH2CONBu2] (6) [UO2(NO3)(2) (C5H7N2CHCONBu2)-Bu-i] (7) and [Ce(NO3)(3){C(3)H(3)N(2)CH(2)CON(i)Bu2}(2)] (11) have been determined by single crystal X-ray diffraction methods. Preliminary extraction studies of the ligand L-5 with U(VI) and Pu(IV) in tracer level showed an appreciable extraction for U(VI) and Pu(TV) up to 10 M HNO3 but not for Am(III). Thermal studies of the compounds 6 and 7 in air revealed that the ligands can be destroyed completely on incineration. (c) 2007 Elsevier Ltd. All rights reserved.