Darstellung und Kristallstruktur von [H3N(CH2)3NH3]SbCl5

Using 293 K diffractometer intensity data, the structure of [H3N(CH2)3NH3]SbCl5 has been determined by single crystal X-ray technique and refined to a final Rw of 0.026. The colorless crystals are monoclinic (space group P21/c) with a = 10.1338(5), b = 11.4623(7), c = 11.3668(6) Å, β = 113.52(5)° and Ζ = 4. The structure contains ψ-octahedral SbCl52- anions. A center of symmetry connects two anions forming a (Sb2Cl10)4- unit with rather long Sb—Cl distances for the bridging Cl-atoms (2.92 and 3.68 A, respectively)

Zur Stereochemie des freien Elektronenpaares in AX6E-Systemen, VIII Statisch verzerrte Anionen in [H3N(CH2)3NH3]3(BiX6)2(H2O)2 mit X = Cl, Br

Using 293 K diffractometer intensity data, the crystal structures of [H3N(CH2)3NH3]3(BiX6)2(H2O)2 with X - Cl, Br have been determined by single crystal X-ray technique and refined to a final Rw of 0.027 and 0.043, respectively. The structures are isotypic, space group P21/c, Z = 2 with a = 14.415(1). b = 9.7401(7), c = 12.4609(9)Å, β = 105.997(8)°for X - Cl and a = 14.794(2), b = 10.127(2), c = 12.853(2)Å, β = 105.68(2)° for X - Br. Statically distorted BiX63- octahedra confirm the symmetry rules for the stereochemistry of the lone pair electrons in AX6E-systems. Basic structural data for all compounds containing BiX63- and SbXh3 ions (X = Cl, Br, I) known to date are given including the ⊿-values as a measure for the distortion of the octahedral coordination polyhedron

Die Kristallstrukturen von Verbindungen des Typs A2TeX6 (A = K, NH4, Rb, Cs; X = Cl, Br, I)

With the determination of the crystal structure of (NH4)2TeI6 the list of the descriptions of A2TeX6 structures is further completed. At 293 K three structure types are observed with an antifluorite packing of cations and anions: The cubic K2PtCl6 type structure (space group Fm 3̄ m, Z = 4), the tetragonal Rb2TeI6 type structure (space group P4/mnc, Z = 2), and the monoclinic K2TeBr6 type structure (space group P21/n, Z = 2). The latter type was found for (NH4)2TeI6 with a = 8.0694(7), b = 8.0926(9), c = 11.7498(8) Å and β = 89.605(8)° and refined to a final Rw of 0.065. From ionic radii ratios the symmetry of the A2MX6 type structures can be predicted including a prediction of low temperature instability (soft mode condensation). Group-subgroup relationships connect the corresponding space groups and the space groups of the high/low temperature polymorphs

A Mechanized Proof of a Textbook Type Unification Algorithm

Unification is the core of type inference algorithms for modern functional programming languages, like Haskell and SML. As a first step towards a formalization of a type inference algorithm for such programming languages, we present a formalization in Coq of a type unification algorithm that follows classic algorithms presented in programming language textbooks. We also report on the use of such formalization to build a correct type inference algorithm for the simply typed λ-calculus

Comparando o Desempenho de Implementações de Tabelas Hash Concorrentes em Haskell

Implementar um algoritmo de tabela hash concorrente que extraia desempenho está longe de ser uma tarefa computacional trivial. Neste artigo apresentamos sete diferentes implementações de tabelas hash em Haskell, explorando desde modelos de sincronização de baixo nível até os de mais alta abstração como memórias transacionais. Nos testes realizados a implementação usando a biblioteca STM Haskell de memória transacional foi a que apresentou melhor desempenho

Neurophysiology of Skin Thermal Sensations

Undoubtedly, adjusting our thermoregulatory behavior represents the most effective mechanism to maintain thermal homeostasis and ensure survival in the diverse thermal environments that we face on this planet. Remarkably, our thermal behavior is entirely dependent on the ability to detect variations in our internal (i.e., body) and external environment, via sensing changes in skin temperature and wetness. In the past 30 years, we have seen a significant expansion of our understanding of the molecular, neuroanatomical, and neurophysiological mechanisms that allow humans to sense temperature and humidity. The discovery of temperature‐activated ion channels which gate the generation of action potentials in thermosensitive neurons, along with the characterization of the spino‐thalamo‐cortical thermosensory pathway, and the development of neural models for the perception of skin wetness, are only some of the recent advances which have provided incredible insights on how biophysical changes in skin temperature and wetness are transduced into those neural signals which constitute the physiological substrate of skin thermal and wetness sensations. Understanding how afferent thermal inputs are integrated and how these contribute to behavioral and autonomic thermoregulatory responses under normal brain function is critical to determine how these mechanisms are disrupted in those neurological conditions, which see the concurrent presence of afferent thermosensory abnormalities and efferent thermoregulatory dysfunctions. Furthermore, advancing the knowledge on skin thermal and wetness sensations is crucial to support the development of neuroprosthetics. In light of the aforementioned text, this review will focus on the peripheral and central neurophysiological mechanisms underpinning skin thermal and wetness sensations in humans. © 2016 American Physiological Society. Compr Physiol 6:1279‐1294, 2016