Helical phases assembled from achiral molecules : Twist-bend nematic and helical filamentary B4 phases formed by mesogenic dimers

Funding Information: National Science Centre (Poland) under the grant no. 2016/22/A/ST5/00319. Special acknowledgement and thanks to professor Dong Ki Yoon's group for providing the AAO membranes.Peer reviewedPublisher PD

Metal-Dependent Cytotoxic and Kinesin Spindle Protein Inhibitory Activity of Ru, Os, Rh, and Ir Half-Sandwich Complexes of Ispinesib-Derived Ligands

Ispinesib is a potent inhibitor of kinesin spindle protein (KSP), which has been identified as a promising target for antimitotic anticancer drugs. Herein, we report the synthesis of half-sandwich complexes of Ru, Os, Rh, and Ir bearing the ispinesib-derived N,N-bidentate ligands (R)- and (S)-2-(1-amino-2-methylpropyl)-3-benzyl-7-chloroquinazolin-4(3H)-one and studies on their chemical and biological properties. Using the enantiomerically pure (R)- and (S)-forms of the ligand, depending on the organometallic moiety, either the SM,R or RM,S diastereomers, respectively, were observed in the molecular structures of the Ru- and Os(cym) (cym = η6-p-cymene) compounds, whereas the RM,R or SM,S diastereomers were found for the Rh- and Ir(Cp*) (Cp* = η5-pentamethylcyclopentadienyl) derivatives. However, density functional theory (DFT) calculations suggest that the energy difference between the diastereomers is very small, and therefore a mixture of both will be present in solution. The organometallics exhibited varying antiproliferative activity in a series of human cancer cell lines, with the complexes featuring the (R)-enantiomer of the ligand being more potent than the (S)-configured counterparts. Notably, the Rh and Ir complexes demonstrated high KSP inhibitory activity, even at 1 nM concentration, which was independent of the chirality of the ligand, whereas the Ru and especially the Os derivatives were much less active

Methane adsorption in metal-organic frameworks containing nanographene linkers: a computational study

Metal-organic framework (MOF) materials are known to be amenable to expansion through elongation of the parent organic linker. For a family of model (3,24)-connected MOFs with the rht topology, in which the central part of organic linker comprises a hexabenzocoronene unit, the effect of the linker type and length on their structural and gas adsorption properties is studied computationally. The obtained results compare favourably with known MOF materials of similar structure and topology. We find that the presence of a flat nanographene-like central core increases the geometric surface area of the frameworks, sustains additional benzene rings, promotes linker elongation and the efficient occupation of the void space by guest molecules. This provides a viable linker modification method with potential for enhancement of uptake for methane and other gas molecules

Time-resolved single-crystal X-ray crystallography

In this chapter the development of time-resolved crystallography is traced from its beginnings more than 30 years ago. The importance of being able to “watch” chemical processes as they occur rather than just being limited to three-dimensional pictures of the reactant and final product is emphasised, and time-resolved crystallography provides the opportunity to bring the dimension of time into the crystallographic experiment. The technique has evolved in time with developments in technology: synchrotron radiation, cryoscopic techniques, tuneable lasers, increased computing power and vastly improved X-ray detectors. The shorter the lifetime of the species being studied, the more complex is the experiment. The chapter focusses on the results of solid-state reactions that are activated by light, since this process does not require the addition of a reagent to the crystalline material and the single-crystalline nature of the solid may be preserved. Because of this photoactivation, time-resolved crystallography is often described as “photocrystallography”. The initial photocrystallographic studies were carried out on molecular complexes that either underwent irreversible photoactivated processes where the conversion took hours or days. Structural snapshots were taken during the process. Materials that achieved a metastable state under photoactivation and the excited (metastable) state had a long enough lifetime for the data from the crystal to be collected and the structure solved. For systems with shorter lifetimes, the first time-resolved results were obtained for macromolecular structures, where pulsed lasers were used to pump up the short lifetime excited state species and their structures were probed by using synchronised X-ray pulses from a high-intensity source. Developments in molecular crystallography soon followed, initially with monochromatic X-ray radiation, and pump-probe techniques were used to establish the structures of photoactivated molecules with lifetimes in the micro- to millisecond range. For molecules with even shorter lifetimes in the sub-microsecond range, Laue diffraction methods (rather than using monochromatic radiation) were employed to speed up the data collections and reduce crystal damage. Future developments in time-resolved crystallography are likely to involve the use of XFELs to complete “single-shot” time-resolved diffraction studies that are already proving successful in the macromolecular crystallographic field.</p

Application of Double Current Bridge-Circuit for Simultaneous Measurements of Strain and Temperature

Opisano czterozaciskowy (4T) układ mostka rezystancyjnego zasilanego niekonwencjonalnie z dwóch źródeł prądowych i o dwu wyjściach z obu jego przekątnych, nazwany mostkiem dwuprądowym (2J). Podano napięcia wyjściowe niezrównoważonego mostka jako funkcje rezystancji jego gałęzi lub ich przyrostów od równowagi mostka w wartościach względnych. Przedstawiono przykład realizacji dwuparametrowego (2D) przetwornika do równoczesnego pomiaru odkształcenia i temperatury wykorzystującego ten mostek i omówiono wybrane wyniki pomiarów eksperymentalnej jego weryfikacji.A four-terminal (4T) bridge circuit unconventionally supplied by two current sources connected in parallel to opposite arms, named double current bridge (2J) is presented. It has two different outputs from both diagonals. The output voltages described as functions of arm resistances or their increments from bridge balance in relative units are given. Example of its application is proposed. Signals conditioning formulas of the two-parameter (2D) measurement - of strain and temperature are discussed in details. Some results of experimental verification of instrumetation circuit, designed for this bridge are shortly presented

Simultaneous measurement of two parameters by double current supplied bridge

A four-terminal (4T) bridge-circuit, with two voltage outputs is presented. This circuit, named as double current bridge is supplied by two equal current sources connected in parallel to opposite arms (2J) or by one such source switched between those arms (2x1J). Two output voltages from bridge diagonals as functions of arm resistance increments in absolute and in relative units are given. Also the example of this bridge application is proposed. Signal conditioning formulas of two-parameter measurement on the example of strain and temperature are discussed in detail. Some results obtained with the use of this bridge-circuit are briefly described

Applied Crystallography The LaueUtil toolkit for Laue photocrystallography. I. Rapid orientation matrix determination for intermediate-size-unit-cell Laue data

A new method for determination of the orientation matrix of Laue X-ray data is presented. The method is based on matching of the experimental patterns of central reciprocal lattice rows projected on a unit sphere centered on the origin of the reciprocal lattice with the corresponding pattern of a monochromatic data set on the same material. This technique is applied to the complete data set and thus eliminates problems often encountered when single frames with a limited number of peaks are to be used for orientation matrix determination. Application of the method to a series of Laue data sets on organometallic crystals is described. The corresponding program is available under a Mozilla Public License-like open-source license

Специализированный измерительно-информационный преобразователь

In this paper the simple model of measure-informative transformer is presented. It is destinated to discriminating of two causes of symptoms in low urinary tracts: benign prostatic hyperplasia (BPH) and prostate cancer (PC). The inputs of this transformer are results of physical investigations (laboratory investigations, measurements of pressures, flow, etc.) as well as information about patient in digital form (subordinated suitable numerical scales). Outputs are described in the form of studied symptoms. Probability of occurrence of given cause is the result of processing.Надана проста модель вимірювально-інформаційного перетворювача, який призначений для визначення двох причин симптомів сечовивідних путей: доброякісної гіперплазії та рака простати.Предложена простая модель измерительно-информационного преобразователя, предназначенного для определения двух причин симптомов мочевыводящих путей: доброкачественной гиперплазии и рака простаты