Co(II)-Based single-ion magnets with 1,1'-ferrocenediyl-bis(diphenylphosphine) metalloligands.

Herein, we report on investigations of magnetic and spectroscopic properties of three heterobimetallic Fe(ii)-Co(ii) coordination compounds based on the tetracoordinate {CoP2X2} core encapsulated by dppf metalloligand, where X = Cl (1), Br (2), I (3), dppf = 1,1'-ferrocenediyl -bis(diphenylphosphine). The analysis of static magnetic data has revealed the presence of axial magnetic anisotropy in compounds (1) and (2) and this was further confirmed by high-frequency electron spin resonance (HF-ESR) spectroscopy. Dynamic magnetic data confirmed that (1) and (2) behave as field-induced Single-Ion Magnets (SIMs). Together with bulk studies, we have also tested the possibility of depositing (2) as thick films on Au(111), glass, and polymeric acetate by drop-casting as well as thermal sublimation, a key aspect for the development of future devices embedding these magnetic objects.

Self-driving laboratory for accelerated discovery of thin-film materials.

Discovering and optimizing commercially viable materials for clean energy applications typically takes more than a decade. Self-driving laboratories that iteratively design, execute, and learn from materials science experiments in a fully autonomous loop present an opportunity to accelerate this research process. We report here a modular robotic platform driven by a model-based optimization algorithm capable of autonomously optimizing the optical and electronic properties of thin-film materials by modifying the film composition and processing conditions. We demonstrate the power of this platform by using it to maximize the hole mobility of organic hole transport materials commonly used in perovskite solar cells and consumer electronics. This demonstration highlights the possibilities of using autonomous laboratories to discover organic and inorganic materials relevant to materials sciences and clean energy technologies.

Does stigma curvature promote delayed selfing? An experimental investigation in Triodanis perfoliata (Campanulaceae).

Self-fertilisation that is delayed until after opportunities for outcrossing have ceased has been argued to provide both the reproductive assurance benefits of selfing and the genetic advantages of outcrossing. In the Campanulaceae, presentation of pollen on stylar hairs and progressive stigma curvature have been hypothesised to facilitate delayed selfing, but experimental tests are lacking. Stigma curvature is common in Campanula, a genus largely characterised by self-incompatibility, and therefore is unlikely to have initially evolved to promote self-fertilisation. In derived self-compatible species, however, stigma curvature might serve the secondary function of delayed selfing. We investigated delayed selfing in Triodanis perfoliata, a self-compatible relative of Campanula. Using floral manipulation experiments and pollen tube observations, we quantified the extent and timing of self-pollination. Further, we hypothesised that, if stigma curvature provides the benefit of delayed selfing in Triodanis, selection should have favoured retention of self-pollen through the loss of a stylar hair retraction mechanism. Results of a stigma removal experiment indicated that autonomous selfing produces partial seed set, but only some selfing was delayed. Pollen tube observations and a flower senescence assay also supported the finding of partial delayed selfing. Scanning electron microscopy revealed that pollen-collecting hairs retract during anthesis, which may limit the extent of delayed selfing. Delayed selfing appeared to be only partially effective in T. perfoliata. The stylar hair retraction in this species would seem to contradict selection for selfing. We suggest that caution and rigour are needed in interpreting floral traits as adaptive mechanisms for delayed selfing.

[Internal hernia as a cause of small bowel obstruction]. / Vnitrní kýla jako prícina ileu tenkého streva.

Internal hernia is a rare cause of acute small bowel obstruction and may be difficult to diagnose. We would like to use two case reports to demonstrate that laparoscopy is a feasible treatment method for incarcerated internal hernias.Key words: intestinal obstruction - internal hernia - laparoscopy.

Evidence for superconductivity in Li-decorated monolayer graphene.

Monolayer graphene exhibits many spectacular electronic properties, with superconductivity being arguably the most notable exception. It was theoretically proposed that superconductivity might be induced by enhancing the electron-phonon coupling through the decoration of graphene with an alkali adatom superlattice [Profeta G, Calandra M, Mauri F (2012) Nat Phys 8(2):131-134]. Although experiments have shown an adatom-induced enhancement of the electron-phonon coupling, superconductivity has never been observed. Using angle-resolved photoemission spectroscopy (ARPES), we show that lithium deposited on graphene at low temperature strongly modifies the phonon density of states, leading to an enhancement of the electron-phonon coupling of up to λ ≃ 0.58. On part of the graphene-derived π*-band Fermi surface, we then observe the opening of a Δ ≃ 0.9-meV temperature-dependent pairing gap. This result suggests for the first time, to our knowledge, that Li-decorated monolayer graphene is indeed superconducting, with Tc ≃ 5.9 K.

Repair of chronic tympanic membrane perforations with long-term epidermal growth factor.

Chronic tympanic membrane (TM) perforation is a common problem worldwide. Recent reports have shown epidermal growth factor (EGF) to stimulate healing in approximately 80% of chronic TM perforations in chinchillas when applied in three doses over 1 week. The objective of this controlled study is to evaluate the efficacy of long-term EGF in the closure of TM perforations. Chronic chinchilla TM perforations were treated with EGF for up to 6 weeks. One hundred percent (17 of 17) of treatment group perforations completely healed. However, two new findings with this long dosing scheme were reperforation on long-term follow-up and three TMs with cholesteatomas. It is likely that reperforation was due to a progressive thinning seen with prolonged EGF application. Long-term EGF use is not recommended for the treatment of TM perforations because of possible wound healing impairment and possible cholesteatoma induction.

A contemporaneous comparison of hospital charges for laparoscopic and open Nissen fundoplication.

Surgical treatment of gastroesophageal reflux disease is increasingly recognized as a cost-effective alternative to long-term medical therapy. This fact, coupled with the advent of laparoscopic fundoplication as a safe and efficacious alternative to open surgery, underscores the importance of determining the costs associated with laparoscopic treatment. Hospital costs and charges of patients undergoing open (N = 9) and laparoscopic (N = 11) fundoplication were retrospectively analyzed. Both procedures were performed during the same time period (6/91-6/93), at the same hospital, and by the same surgical team. Operative time, and hospital stay, were recorded in addition to total, operating room, anesthesia, sterile supplies, and hospital room charges. Figures are reported as mean values +/- standard error of the mean. The Wilcoxon signed rank test was used for comparison of groups. Operative time (221 +/- 18 vs 165 +/- 12 min, P = 0.033) was longer in the laparoscopic group, while hospital stay (5.8 +/- 02 vs 8.8 +/- 04 days, P < 0.001) was significantly shorter. Total hospital costs were similar for both groups of patients ($14,615 +/- 863 vs $15,891 +/- 921, P = 0.247). Overall hospital charges were nearly identical ($26,634 +/- 1376 vs $27,189 +/- 1753, P = 0.803). A detailed analysis demonstrated cost shifting, with laparoscopic fundoplication resulting in significantly higher charges associated with events in the operating room. Operating room ($6,064 +/- 252 vs $4,283 +/- 380, P = 0.001), sterile supplies ($6,214 +/- 508 vs $5,403 +/- 390), and anesthesia charges ($1,593 +/- 76 vs $1,122 +/- 95, P < 0.001) were all greater in the laparoscopic group.(ABSTRACT TRUNCATED AT 250 WORDS)

Multiple trauma in the achondroplastic dwarf: an emergency medicine physician perspective case report and literature review.

Although uncommon, the achondroplastic dwarf (AD) may become the victim of multiple trauma, presenting special challenges for the emergency department (ED) physician. Traditional management of airway, breathing, circulation, and neurological disability is altered by the unique anatomic features of achondroplasia. Despite facial abnormalities observed in the AD, orotracheal and nasotracheal intubation are usually accomplished without particular difficulty; however, abnormalities of the base of the skull and cervical spine make hyperextension of the neck especially hazardous in these patients. The lungs are functionally normal, although vital capacity is decreased and thoracic case abnormalities and abdominal obesity impair lung expansion. Vascular access in the AD is difficult. Peripheral access is difficult because of excessive subcutaneous fat, whereas central venous access is complicated by neck, chest wall, and spinal abnormalities that obscure commonly used anatomic landmarks. Major neurological syndromes observed in ADs are hydrocephalus, cervical medullary compression, and thoracolumbar stenosis. The ED physician should recognize these syndromes, their potential to produce neurological disability, and their unique implications for trauma.

Treatment of metal-contaminated water using bacterial sulfate reduction: results from pilot-scale reactors.

Simple anaerobic reactors were installed to treat metal-contaminated water in an underground coal mine and at a smelting residues dump in Pennsylvania. The reactors consisted of barrels and tanks filled with spent mushroom compost, within which bacterial sulfate reduction became established. Concentrations of Al, Cd, Fe, Mn, Ni, and Zn were typically lowered by over 95% as contaminated water flowed through the reactors. Cadmium, Fe, Ni, and some Zn were retained as insoluble metal sulfides following their reaction with bacterially generated H(2)S. Aluminum, Mn, and some Zn hydrolyzed and were retained as insoluble hydroxides or carbonates. Reactor effluents were typically circumneutral in pH and contained net alkalinity. The principal sources of alkalinity in the reactors were bacterial sulfate reduction and limestone dissolution. This article examines the chemistry of the reactor systems and the opportunities for enhancing their metal-retaining and alkalinity-generating potential.

Selective abolition of OFF responses in kainic acid-lesioned chicken retina.

When ganglion cell responses were recorded from optic axons in the superficial layers of the chicken optic tectum, the responses recorded are predominantly ON-OFF transient, with some ON transient, and rare OFF transient responses. Several weeks after excitotoxic lesion of the retina with 40 nmol of kainic acid injected intravitreally, only ON transient responses could be recorded from the contralateral optic tectum. ON response latency and threshold were not affected. At low light intensities responses in the kainic acid-lesioned retinas showed a sustained component which was not detected in control retinas, but at high light intensities, the sustained component disappeared and the responses were extremely transient. The disappearance of the OFF responses seems to be due to elimination of the OFF component of the responses of cells which are normally ON-OFF transient, rather than the silencing of these cells, leaving only the normally ON transient cells. Morphological evidence suggests that approximately two thirds of the bipolar cells and most amacrine cells are destroyed by the kainic acid lesion (Ingham and Morgan, Neuroscience, 9 (1983) 165-181), and pharmacological logic (Morgan, Prog. Retinal Res., 2 (1983) 247-266) suggests that the missing bipolar cells should be OFF bipolar cells. These results therefore suggest that ON-OFF transient cells receive direct input from bipolar cells, which determines their basic response type. These results also suggest that amacrine cells have little if any role to play in the generation of the basic centre responses of these ON-OFF transient ganglion cells, and that while amacrine cells may have a role in the generation of transient responses in the inner plexiform layer, transient responses can be generated without the intervention of amacrine cells, particularly at high intensities.

Identification of kainic and quisqualic acid receptors on inner retinal cells of the salamander Ambystoma mexicanum.

The presence of kainic (KA) and quisqualic acid (QA) receptors on inner retinal neurones of the axolotl Ambystoma mexicanum has been studied using intracellular recording techniques. In the presence of CoCl2, which blocks neurotransmitter release, KA and QA depolarized the membrane. The minimum concentration of KA that induced a response was 1 microM and a maximum response was obtained with 10 microM (EC50: 3 microM). The operating range of QA was between 0.5 and 5 microM with an EC50 of 1 microM. These data show that inner retinal cells of the axolotl are sensitive to KA and QA. Cis-2,3-piperidine dicarboxylic acid (PDA, 3 mM) completely blocked responses to 5 microM KA, but not those induced by 2 microM QA. This suggests that the KA- and QA-sensitive receptors on inner retinal cells of the salamander are pharmacologically different and that PDA can be a valuable tool in distinguishing KA- and QA-sensitive receptors on these neurones.

Push-pull effect of surround illumination on excitatory and inhibitory inputs to mudpuppy retinal ganglion cells.

1. Changes in membrane potential and conductance were measured in on-centre and off-centre ganglion cells during the responses to illumination of different portions of the receptive field. 2. In on-centre ganglion cells the sustained depolarizing response to steady illumination of the receptive field centre was associated with a net increase in conductance. In the presence of centre illumination, stimulation of the surround with an annulus of light caused a hyperpolarization and a net decrease in conductance, and the reversal potential of the light-evoked response was shifted in a negative direction. In the absence of centre illumination the same annular stimulus caused a hyperpolarization and a net increase in conductance. 3. In off-centre ganglion cells the sustained hyperpolarizing response to centre illumination was associated with a net increase in conductance. In the presence of centre illumination, stimulation of the surround with an annulus caused a depolarization and a net decrease in conductance, and the reversal potential of the light-evoked response was shifted in a positive direction. In the absence of centre illumination the same annulus caused a depolarization and a net increase in conductance. 4. The results indicate that illumination of the receptive field surround can affect both the excitatory and inhibitory sustained inputs to a given ganglion cell in a 'push-pull' manner, by decreasing the synaptic input that was increased by centre illumination and increasing the synaptic input of opposite sign. The relative effect of a given surround illumination on these two inputs, and hence the sign and magnitude of the net conductance change, varied with the amount of centre illumination.

Off-pathway synaptic transmission in the outer retina of the axolotl is mediated by a kainic acid-preferring receptor.

Intracellular recordings were made from OFF-centre bipolar cells and horizontal cells in the superfused axolotl retina eyecup preparation. Bath-applied (+/-)cis-2,3-piperidine dicarboxylic acid (PDA), gamma-D-glutamylglycine (DGG), L-glutamic acid diethyl ester (GDEE), (+/-)2-amino-5-phosphonovaleric acid (2-APV) and magnesium ions were assessed as antagonists of the actions of the photoreceptor transmitter. The rank order of antagonist efficacy was PDA greater than DGG greater than greater than 2-APV = GDEE = Mg2+. The results indicate that transmission at OFF-pathway synapses in the outer retina of the axolotl is mediated by a kainic acid-preferring receptor.

Strychnine blocks transient but not sustained inhibition in mudpuppy retinal ganglion cells.

Transient and sustained inhibitory synaptic inputs to on-centre, off-centre, and on-off ganglion cells in the mudpuppy retina were studied using intracellular recording in the superfused eye-cup preparation. When chemical transmission was blocked with 4 mM-Co2+, application of either glycine or gamma-aminobutyric acid (GABA) caused a hyperpolarization and conductance increase in all ganglion cells. For both amino acids, the responses were dose dependent in the range 0.05-10 mM, with a half-maximal response at about 0.7 mM. Glycine and GABA sensitivities were very similar in all three types of ganglion cells. The response to applied glycine was selectively antagonized by 10(-5) M-strychnine and the response to applied GABA was selectively antagonized by 10(-5) M-picrotoxin. In all ganglion cells, 10(-5) M-strychnine eliminated the transient inhibitory events which occur at the onset and termination of a light stimulus. The block of transient inhibition was associated with a relative depolarization of membrane potential and decrease in conductance at these times. Strychnine had no effect on membrane potential or conductance in darkness or during sustained inhibitory responses to light. Picrotoxin (10(-5) M) did not block transient inhibitory events in any ganglion cells, but did affect other components of their responses. The results suggest that in all three classes of ganglion cells transient inhibition, but not sustained inhibition, may be mediated by glycine or a closely related substance.

A physiologically active kainic acid-preferring receptor in chicken retina.

Neurotoxicity induced by intravitreal injections of kainic acid in the chicken retina was effectively antagonized by piperidine 2,3-dicarboxylic acid and to a lesser extent D-gamma-glutamylglycine. 2-Amino-5-phosphonovaleric acid and glutamic acid diethyl ester were much less effective antagonists. These effects probably result from interactions with a kainic acid-preferring receptor localized on the OFF-centre bipolar cells. Piperidine 2,3-dicarboxylic acid and D-gamma-glutamylglycine also blocked selectively the OFF-responses of ganglion cells while glutamic acid diethyl ester was without effect. 2-Amino-5-phosphonovaleric acid rapidly blocked ON and, much more slowly, OFF-responses. These results are consistent with a role for kainic acid-preferring receptors located on the OFF-centre bipolar cells in chicken retina in physiological transmission between photoreceptors and the OFF-centre bipolar cells.

Sustained and transient synaptic inputs to on-off ganglion cells in the mudpuppy retina.

Synaptic inputs to on-off ganglion cells in mudpuppy retina were studied by measuring current-voltage relations in darkness, during different phases of the response to light, and in the presence of 4 mM-Co2+. The addition of Co2+ to the bathing medium usually caused a hyperpolarization of the membrane potential in darkness and an increase in input resistance, indicating that on-off ganglion cells receive tonic excitatory synaptic input in darkness. Other results suggest that an additional synaptic input, with a reversal potential near the dark potential, may also be active in darkness. At the onset of a light stimulus in the receptive field centre all on-off ganglion cells responded with transient excitatory and inhibitory synaptic events, both of which were due to increases in conductance. Similar transient excitatory and inhibitory events occurred at the termination of the light stimulus. In about one-half of the on-off ganglion cells studied the synaptic activity during steady illumination was the same as in darkness. In the remaining cells steady illumination caused an increase in sustained inhibition.

Intravitreal kainic acid permanently eliminates off-pathways from chicken retina.

Kainic acid rapidly suppresses both ON- and OFF-visually evoked responses in the tectum after injection into the vitreous of chicken eyes. One week after injection the OFF-responses were still suppressed, while ON-responses were detected of similar magnitude but of simplified form to those of control eyes. It is suggested that kainic acid selectively destroys OFF- rather than ON-bipolar cells, while the simplification of the ON-responses is due to the destruction of amacrine cells.