An unusual plank-shaped nematogen with a graphene nanoribbon core

A [12]phenacene exclusively decorated with four lateral hexylester substituents self-assembles into a nematic liquid crystal glass on cooling after melting at high temperature. This uniaxial nematic organization of a plank-shaped nanographene is unprecedented and in strong contrast to the common design rules for liquid crystals. Highly birefringent samples emitting polarized fluorescence can be obtained in homogeneously planar or twisted waveguiding configurations that are stable against crystallization at and below room temperature and up to 100 °C

Control of nanospaces with molecular devices

Cavitands and capsules define nanolitre spaces for recognition, isolation and reactions of small molecules. These systems are usually self-assembled and factors such as solvent size, stoichiometry and packing factors determine what goes into the spaces. Here, we examine two switching devices to control what and when guests get in and out of these hosts: bipyridylmetal chelation and azobenzene photoisomerisation. The effects are reversible by treatment with conventional chelating agents and brief heating, respectively. Accordingly, it is possible to trigger reactions that take place within a cylindrical capsule by light, even though the reaction process is not photochemical by nature. Likewise, the presence of metals can regulate reactions without acting as direct catalysts

Bigger, better, faster: molecular shuttles with sterically non-hindering biisoquinoline chelates

In the past, a variety of mechanically interlocked systems such as catenanes and rotaxaneswere constructed on the basis of Cu(I) coordination chemistry and endocyclic 1,10-phenanthroline ligands. This review reports on the coordination chemistry of a new family of endocyclic bidentate chelators that are sterically non-hindering, namely 8,80-diaryl-substituted 3,30-biisoquinolines. These ligands allow the construction of new multi-component assemblies that are inaccessible with the previously investigated 1,10-phenanthrolines. On the one hand, the sterically non-hindering nature of the new endocyclic chelators makes three component entanglements around octahedral metal centres such as iron(II), cobalt(II) and ruthenium(II) readily possible. On the other hand, it permits the construction of copper-based molecular shuttles that exhibit shuttling kinetics that excels over those of previously investigated analogous systems with 1,10-phenanthrolines. Thus, within this class of molecular machines, a bigger chelator leads to faster molecular movement, i.e. to a better performance of the molecular machine

Autonomic neuropathy influences great toe blood pressure

OBJECTIVE - To assess the influence of autonomic neuropathy on toe blood press RESEARCH DESIGN AND METHODS - The age-matched study subjects included 20 non-insulin-dependent diabetes mellitus (NIDDM) patients with autonomic neuropathy (DN) and 10 NIDDM patients without autonomic neuropathy (D), assessed by standard cardiovascular tests and galvanic skin response, and 8 control subjects (C). None of the subjects had peripheral vascular disease (PVD) (ankle/brachial index 0.9-1.1. RESULTS - The TBP and toe/brachial index (TBI) were significantly lower in DN than in C and D (P < 0.01). The saturation index (SI), the ratio between foot venous and arterial partial pressure of oxygen (PO2), was significantly higher in DN than in C and D (P < 0.05). An inverse relationship was found between TBI and SI (r = 0.554, P = 0.001). CONCLUSIONS - The autonomic nervous system directly influences peripheral circulation. In diabetic patients without PVD, a failure of sympathetic fibers caused by autonomic neuropathy could lead to a reduction of TBP. Therefore, TBP cannot be used as an ischemic index in diabetic patients

ELECTROPHYSIOLOGICAL ASSESSMENT OF VISUAL FUNCTION IN NEWLY-DIAGNOSED IDDM PATIENTS

Electrophysiological tests (electroretinogram, oscillatory potentials, visual evoked potentials, in the basal condition and after photostress) reveal an abnormal function of the visual system in insulin-dependent diabetic (IDDM) patients. The aim of our work was to assess whether electrophysiological abnormalities in visual function exist in newly-diagnosed diabetic patients free of any fluorangiographic signs of retinopathy. Ten control subjects (age 28.7 +/- 2.44 years) and ten IDDM: patients (age 25.2 +/- 6.78 years; disease duration 5.3 +/- 3.5 months) in stable metabolic control (HbA(1C)7.5 +/- 1.1%) were evaluated. Flash-electroretinograms and oscillatory potentials were similar in both groups. Visual evoked potentials (VEP) recorded under basal conditions showed that P100 latency was significantly increased in the diabetic patients compared to control subjects (p < 0.01), while N75-P100 amplitude was similar in both groups. The recovery time of VEP after photostress was equivalent in diabetic patients and control subjects. The impaired basal VEPs suggest an early involvement of the nervous conduction in the optic nerve. However, the preserved flash-electroretinogram and the normal recovery time after photostress indicate that a short disease duration does not induce physiopathological changes in the outer retinal layers or in the macular function

Autonomic neuropathy and transcutaneous oxymetry in diabetic lower extremities

Transcutaneous oxygen tension is a useful method with which to assess the functional status of skin blood flow. The reduced values observed in diabetic patients have been interpreted as a consequence of peripheral vascular disease. However, diabetic patients show lower transcutaneous oxygen tension values than control subjects with equivalent degrees of peripheral vascular disease, suggesting that additional factors are involved. Since the autonomic nervous system influences peripheral circulation, we studied the relationship between autonomic neuropathy and foot transcutaneous oxymetry in non-insulin-dependent diabetic (NIDDM) patients without peripheral vascular disease. The following age-matched patients were selected and evaluated: control subjects, C, (n = 20), NIDDM patients without autonomic neuropathy, D, (n = 16) and with autonomic neuropathy, DN, (n = 20). All diabetic patients showed lower transcutaneous oxygen tension values than control subjects, while no differences were observed between the diabetic patients with and without autonomic neuropathy. In addition the saturation index that increases in the presence of autonomic neuropathy does not correlate with foot TcPO2. In conclusion autonomic neuropathy does not influence foot TcPO2 and therefore it is unlikely that it contributes to development of foot lesions during induction of foot skin ischaemia

ELECTROPHYSIOLOGICAL ASSESSMENT OF VISUAL FUNCTION IN NEWLY-DIAGNOSED IDDM PATIENTS

Electrophysiological tests (electroretinogram, oscillatory potentials, visual evoked potentials, in the basal condition and after photostress) reveal an abnormal function of the visual system in insulin-dependent diabetic (IDDM) patients. The aim of our work was to assess whether electrophysiological abnormalities in visual function exist in newly-diagnosed diabetic patients free of any fluorangiographic signs of retinopathy. Ten control subjects (age 28.7 +/- 2.44 years) and ten IDDM: patients (age 25.2 +/- 6.78 years; disease duration 5.3 +/- 3.5 months) in stable metabolic control (HbA(1C)7.5 +/- 1.1%) were evaluated. Flash-electroretinograms and oscillatory potentials were similar in both groups. Visual evoked potentials (VEP) recorded under basal conditions showed that P100 latency was significantly increased in the diabetic patients compared to control subjects (p < 0.01), while N75-P100 amplitude was similar in both groups. The recovery time of VEP after photostress was equivalent in diabetic patients and control subjects. The impaired basal VEPs suggest an early involvement of the nervous conduction in the optic nerve. However, the preserved flash-electroretinogram and the normal recovery time after photostress indicate that a short disease duration does not induce physiopathological changes in the outer retinal layers or in the macular function

Visual evoked potentials after photostress in newly diagnosed insulin-dependent diabetes patients

Background: The study was performed in order to ascertain whether electrophysiological abnormalities in visual function exist in newly diagnosed diabetic patients. Methods: Visual evoked potentials (VEPs) were assessed under basal conditions and after photostress in normal control subjects and in newly diagnosed diabetic patients free of any fluorescein angiography signs of retinopathy. Results: In basal conditions VEP P100 latency was significantly increased in the diabetic patients compared to controls (P<0.01), while N75-P100 amplitude was similar in both groups. After photostress N75-P100 amplitude (mean percentage decrement) was significantly higher in diabetic patients (P<0.01), while P100 latency (mean increment) and recovery time (time at which VEPs were superimposable on basal condition) were similar in the two groups. Conclusions: The impaired basal VEPs suggest an early involvement of conduction in the optic nerve. In contrast, the preserved recovery time after photostress indicates that a short duration of disease does not induce physiopathological changes in macular function