Cyanide-Bridged Rope-like Chains Based on Trigonal-Bipyramidal [Fe2Cu3] Subunits.

Extending a selected cyanometalate block into a higher dimensional framework continues to present intriguing challenges in the fields of chemistry and material science. Here, we prepared two rope-like chain compounds of {[(Tp*Me)Fe(CN)3]2Cu2X2(L)}·sol (1, X = Cl, L = (MeCN)0.5(H2O/MeOH)0.5, sol = 2MeCN·1.5H2O; 2, X = Br, L = MeOH, sol = 2MeCN·0.75H2O; Tp*Me = tris(3, 4, 5-trimethylpyrazole)borate) in which the cyanide-bridged trigonal-bipyramidal [Fe2Cu3] subunits were linked with the adjacent ones via two vertex Cu(II) centers, providing a new cyanometallate chain archetype. Direct current magnetic study revealed the presence of ferromagnetic couplings between Fe(III) and Cu(II) ions and uniaxial anisotropy due to a favorable alignment of the anisotropic tricyanoiron(III) units. Moreover, compound 1 exhibits single-chain magnet behavior with an appreciable energy barrier of 72 K, while 2 behaves as a metamagnet, likely caused by the subtle changes in the interchain interactions.

Thermo- and photo-induced electron transfer in a series of [Fe2Co2] capsules.

Recently, a family of [Fe2Co2] molecular capsules that display tunable electron transfer-coupled spin transition (ETCST) behavior were reported via a smart approach through Schiff-base condensation of aldehyde-functionalized 2,2-bipyridines (bpyCHO) and 1,7-heptanediamine (H2N(CH2)7NH2). Here, three more capsule complexes {[(TpR)Fe(CN)3]2[Co(bpyCN(CH2)nNCbpy)]2[ClO4]2}·n(solvent) (1, TpR = Tp*, n = 5, sol = 8DMF; 2, TpR = TpMe, n = 9, sol = 5MeCN; and 3, TpR = Tp*, n = 11, sol = 5MeCN), where Tp* = hydridotris(3,5-dimethylpyrazol-1-yl)borate and TpMe = hydridotris(3-methylpyrazol-1-yl)borate are reported, demonstrating a successful extension of such an approach with other alkyldiamines of different lengths. Combined X-ray crystallographic, infrared spectroscopic and magnetic studies reveal incomplete electron transfer with either changing temperature or upon light exposure.

Noise helps cochlear implant listeners to categorize vowels.

Theoretical studies demonstrate that controlled addition of noise can enhance the amount of information transmitted by a cochlear implant (CI). The present study is a proof-of-principle for whether stochastic facilitation can improve the ability of CI users to categorize speech sounds. Analogue vowels were presented to CI users through a single electrode with independent noise on multiple electrodes. Noise improved vowel categorization, particularly in terms of an increase in information conveyed by the first and second formant. Noise, however, did not significantly improve vowel recognition: the miscategorizations were just more consistent, giving the potential to improve with experience.

Differentiating Radiation-Induced Necrosis from Tumor Progression After Stereotactic Radiosurgery for Brain Metastases, Using Evaluation of Blood Flow with Arterial Spin Labeling (ASL): The Importance of Setting a Baseline.

OBJECTIVE: This study evaluated the usefulness of arterial spin labeling (ASL) for assessment of tumor blood flow (TBF) and cerebral blood flow (CBF) before Gamma Knife surgery (GKS) for intracranial metastases, in order to analyze the variability of perfusion characteristics at baseline and to reveal how these data may impact differentiation of radiation-induced effects from tumor progression during follow-up. METHODS: Radiological data from 87 patients with intracranial metastases of solid cancers, who underwent TBF/CBF analysis by means of ASL at the Hawaii Advanced Imaging Institute between 2015 and 2018 both before and after GKS, were reviewed retrospectively. Only cases with a largest tumor diameter of ≥10 mm were included in the study cohort (N = 53). RESULTS: In comparison with CBF in the healthy contralateral cerebral cortex, TBF before GKS was greater in 32 cases (60%), lesser in 7 cases (13%), and equivalent in 14 cases (27%). There was significant variability in TBF both within and between histologically different groups of tumors. CONCLUSION: Since, at baseline, approximately 40% of intracranial metastases have TBF that is lesser or equivalent to CBF, increased blood flow in the contrast-enhancing lesion after GKS may have insufficient sensitivity for identification of tumor progression. Availability of baseline TBF data may significantly facilitate differential diagnosis in such cases.

Spacers and Valved Holding Chambers-The Risk of Switching to Different Chambers.

Spacers are pressurized metered-dose inhaler (pMDI) accessory devices developed to reduce problems of poor inhaler technique with pMDIs. Spacers that feature a 1-way inspiratory valve are termed valved holding chambers (VHCs); they act as aerosol reservoirs, allowing the user to actuate the pMDI device and then inhale the medication in a 2-step process that helps users overcome challenges in coordinating pMDI actuation with inhalation. Both spacers and VHCs have been shown to increase fine particle delivery to the lungs, decrease oropharyngeal deposition, and reduce corticosteroid-related side effects such as throat irritation, dysphonia, and oral candidiasis commonly seen with the use of pMDIs alone. Spacers and VHCs are not all the same, and also are not interchangeable: the performance may vary according to their size, shape, material of manufacture and propensity to become electrostatically charged, their mode of interface with the patient, and the presence or otherwise of valves and feedback devices. Thus, pairing of a pMDI plus a spacer or a VHC should be considered as a unique delivery system. In this Rostrum we discuss the risk potential for a patient getting switched to a spacer or VHC that delivers a reduced dose medication.

Helping people live with chronic obstructive pulmonary disease.

Chronic obstructive pulmonary disease (COPD) is a long-term condition characterised by persistent respiratory symptoms and airflow limitation. It is preventable and treatable, but still results in high levels of morbidity and mortality. This affects health service costs, but more importantly it affects the person with COPD, and their relatives and carers. If healthcare services continue to focus on managing the disease process rather than the person living with the disease itself, they may continue to produce the same outcomes and fail to substantially reduce the burden of the disease. Helping people live with COPD requires clinicians to communicate effectively with people, families and carers and share multidisciplinary team decisions with patients. Clinicians must consider the physical, psychological, social and spiritual implications of the disease. This article explores how nurses can have a positive effect on the lives of people with COPD, and provides practical strategies and suggestions on giving them effective support.

Development and Validation of a Lateral Flow Immunoassay for the Rapid Screening of Okadaic Acid and All Dinophysis Toxins from Shellfish Extracts.

A single-step lateral flow immunoassay was developed and validated to detect okadaic acid (OA) and dinophysis toxins (DTXs), which cause diarrhetic shellfish poisoning. The performance characteristics of the test were investigated, in comparison to reference methods (liquid chromatography tandem mass spectrometry and/or bioassay), using both spiked and naturally contaminated shellfish. A portable reader was used to generate a qualitative result, indicating the absence or presence of OA-group toxins, at concentrations relevant to the maximum permitted level (MPL). Sample homogenates could be screened in 20 min (including extraction and assay time) for the presence of free toxins (OA, DTX1, DTX2). DTX3 detection could be included with the addition of a hydrolysis procedure. No matrix effects were observed from the species evaluated (mussels, scallops, oysters, and clams). Results from naturally contaminated samples (n = 72) indicated no false compliant results and no false noncompliant results at <50% MPL. Thus, the development of a new low-cost but highly effective tool for monitoring a range of important phycotoxins has been demonstrated.

Development and Validation of a Novel Lateral Flow Immunoassay (LFIA) for the Rapid Screening of Paralytic Shellfish Toxins (PSTs) from Shellfish Extracts.

A single-step lateral flow immunoassay (LFIA) was developed and validated for the rapid screening of paralytic shellfish toxins (PSTs) from a variety of shellfish species, at concentrations relevant to regulatory limits of 800 µg STX-diHCl equivalents/kg shellfish meat. A simple aqueous extraction protocol was performed within several minutes from sample homogenate. The qualitative result was generated after a 5 min run time using a portable reader which removed subjectivity from data interpretation. The test was designed to generate noncompliant results with samples containing approximately 800 µg of STX-diHCl/kg. The cross-reactivities in relation to STX, expressed as mean ± SD, were as follows: NEO: 128.9% ± 29%; GTX1&4: 5.7% ± 1.5%; GTX2&3: 23.4% ± 10.4%; dcSTX: 55.6% ± 10.9%; dcNEO: 28.0% ± 8.9%; dcGTX2&3: 8.3% ± 2.7%; C1&C2: 3.1% ± 1.2%; GTX5: 23.3% ± 14.4% (n = 5 LFIA lots). There were no indications of matrix effects from the different samples evaluated (mussels, scallops, oysters, clams, cockles) nor interference from other shellfish toxins (domoic acid, okadaic acid group). Naturally contaminated sample evaluations showed no false negative results were generated from a variety of different samples and profiles (n = 23), in comparison to reference methods (MBA method 959.08, LC-FD method 2005.06). External laboratory evaluations of naturally contaminated samples (n = 39) indicated good correlation with reference methods (MBA, LC-FD). This is the first LFIA which has been shown, through rigorous validation, to have the ability to detect most major PSTs in a reliable manner and will be a huge benefit to both industry and regulators, who need to perform rapid and reliable testing to ensure shellfish are safe to eat.

Thermochromic and photoresponsive cyanometalate Fe/Co squares: toward control of the electron transfer temperature.

Two structurally related and photoresponsive cyanide-bridged Fe/Co square complexes, {Fe2Co2}, are reported: {[(Tp(Me))Fe(CN)3]2[Co(bpy)2]2[(Tp(Me))Fe(CN)3]2}·12H2O (2) and {[(Tp(Me))Fe(CN)3]2[Co(bpy)2]2[BPh4]2}·6MeCN (3), where Tp(Me) and bpy are hydridotris(3-methylpyrazol-1-yl)borate and 2,2'-bipyridine, respectively. Through electrochemical and spectroscopic studies, the Tp(Me) ligand appears to be a moderate σ donor in comparison to others in the [NEt4][(Tp(R))Fe(III)(CN)3] series [where Tp(R) = Tp, hydridotris(pyrazol-1-yl)borate; Tp(Me) = hydridotris(3-methylpyrazol-1-yl)borate; pzTp = tetrakis(pyrazol-1-yl)borate; Tp* = hydridotris(3,5-dimethylpyrazol-1-yl)borate; Tp*(Me) = hydridotris(3,4,5-trimethylpyrazol-1-yl)borate]. The spectroscopic, structural, and magnetic data of the {Fe2Co2} squares indicate that thermally-induced intramolecular electron transfer reversibly converts {Fe(II)LS(µ-CN)Co(III)LS} pairs into {Fe(III)LS(µ-CN)Co(II)HS} units near ca. 230 and 244 K (T1/2) for 2 and 3, respectively (LS: low spin; HS: high spin). These experimental results show that 2 and 3 display light-induced {Fe(III)LS(µ-CN)Co(II)HS} metastable states that relax to thermodynamic {Fe(II)LS(µ-CN)Co(III)LS} ones at ca. 90 K. Ancillary Tp(R) ligand donor strength appears to be the dominant factor for tuning electron transfer properties in these {Fe2Co2} complexes.

Development and validation of the first high performance-lateral flow immunoassay (HP-LFIA) for the rapid screening of domoic acid from shellfish extracts.

A lateral flow immunoassay (LFIA) has been developed and fully validated to detect the primary amnesic shellfish poisoning (ASP) toxin, domoic acid (DA). The performance characteristics of two versions of the test were investigated using spiked and naturally contaminated shellfish (mussels, scallops, oysters, clams, and cockles). The tests provide a qualitative result, to indicate the absence or presence of DA in extracts of shellfish tissues, at concentrations that are relevant to regulatory limits. The new rapid assay (LFIA version 2) was designed to overcome the performance limitations identified in the first version of the assay. The improved test uses an electronic reader to remove the subjective nature of the generated results, and the positive cut-off for screening of DA in shellfish was increased from 10 ppm (version 1) to 17.5 ppm (version 2). A simple extraction and test procedure was employed, which required minimal equipment and materials; results were available 15 min after sample preparation. Stability of the aqueous extracts at room temperature (22 °C) at four time points (up to 245 min after extraction) and across a range of DA concentrations was 100.3±1.3% and 98.8±2.4% for pre- and post-buffered extracts, respectively. The assay can be used both within laboratory settings and in remote locations. The accuracy of the new assay, to indicate negative results at or below 10 ppm DA, and positive results at or above 17.5 ppm, was 99.5% (n=216 tests). Validation data were obtained from a 2-day, randomised, blind study consisting of multiple LFIA lots (n=3), readers (n=3) and operators (n=3), carrying out multiple extractions of mussel tissue (n=3) at each concentration (0, 10, 17.5, and 20 ppm). No matrix effects were observed on the performance of the assay with different species (mussels, scallops, oysters, clams, and cockles). There was no impact on accuracy or interference from other phycotoxins, glutamic acid or glutamine with various strip incubations (8, 10, and 12 min). The accuracy of the assay, using naturally contaminated samples to indicate negative results at or below 12.5 ppm and positive results at or above 17.5 ppm, was 100%. Variability between three LFIA lots across a range of DA concentrations, expressed as coefficient of variation (% CV), was 1.1±0.4% (n=2 days) based on quantitative readings from the electronic reader. During an 8 week stability study, accuracy of the method with test strips stored at various temperatures (6, 22, 37 and 50 °C) was 100%. Validation for both versions included comparisons with results obtained using reference LC-UV methods.

Syntheses, structures, and magnetic properties of a novel mer-[(bbp)Fe(III)(CN)3](2-) building block (bbp: bis(2-benzimidazolyl)pyridine dianion) and its related heterobimetallic Fe(III)-Ni(II) complexes.

A new symmetrical tricyanide building block mer-[Fe(bbp)(CN)3](2-) [1; bbp = bis(2-benzimidazolyl)pyridine dianion] has been prepared and structurally and magnetically characterized. It forms a new low-spin meridionally capped {Fe(III)L(CN)3} fragment with the tridentate bbp ligand. The reaction of 1 with Ni(II) salts in the presence of various ancillary ligands affords several new cyanido-bridged complexes: a trinuclear complex {[Ni(ntb)(MeOH)]2[Fe(bbp)(CN)3][ClO4]2}·2MeOH (2), a tetranuclear compound {[Ni(tren)]2[Fe(bbp)(CN)3]2}·7MeOH (3), and a one-dimensional heterobimetallic system: {[Ni(dpd)2]2[Fe(bbp)(CN)3]2}·9MeOH·3H2O (4) [ntb = tris(2-benzimidazolylmethyl)amine, tren = tris(2-aminoethyl)amine, and dpd = 2,2-dimethyl-1,3-propanediamine]. The structural data shows that 2 is a linear complex in which a central Fe(III) ion links two adjacent Ni(II) ions via axial cyanides, while 3 is a molecular square that contains cyanido-bridged Ni(II) and Fe(III) ions at alternate corners. Complex 4 is a one-dimensional system that is composed of alternating cyanido-bridged Ni(II) and Fe(III) centers. Compounds 2-4 display extensive hydrogen bonding and moderately strong π-π stacking interactions in the solid state. Magnetic studies show that ferromagnetic exchange is operative within the Fe(III)LS(µ-CN)Ni(II) units of 2-4.

Pitch shifts on mistuned harmonics in the presence and absence of corresponding in-tune components.

Mistuning a harmonic produces an exaggerated change in its pitch, a component-pitch shift. The origin of these pitch shifts was explored by manipulations intended to alter the grouping status of a mistuned target component in a periodic complex tone. In experiment 1, which used diotic presentation, reinstating the corresponding harmonic (in-tune counterpart) caused the pitch shifts on the mistuned target largely to disappear for components 3 and 4, although they remained for component 2. A computational model of component-pitch shifts, based on harmonic cancellation, was unable to explain the near-complete loss of pitch shifts when the counterpart was present; only small changes occurred. In experiment 2, the complex tone and mistuned component 4 were presented in the left ear and the in-tune counterpart was presented in the right. The in-tune counterpart again reduced component-pitch shifts, but they were restored when a captor complex into which the counterpart fitted as harmonic 3 was added in the right ear; presumably by providing an alternative grouping possibility for the counterpart. It is proposed that component-pitch shifts occur only if the mistuned component is selected to contribute to the complex-tone percept; these shifts are eliminated if it is displaced by a better candidate.

The influence of adaptation and inhibition on the effects of onset asynchrony on auditory grouping.

Onset asynchrony is an important cue for auditory scene analysis. For example, a harmonic of a vowel that begins before the other components contributes less to the perceived phonetic quality. This effect was thought primarily to involve high-level grouping processes, because the contribution can be partly restored by accompanying the leading portion of the harmonic (precursor) with a synchronous captor tone an octave higher, and hence too remote to influence adaptation of the auditory-nerve response to that harmonic. However, recent work suggests that this restoration effect arises instead from inhibitory interactions relatively early in central auditory processing. The experiments reported here have reevaluated the role of adaptation in grouping by onset asynchrony and explored further the inhibitory account of the restoration effect. Varying the frequency of the precursor in the range ± 10% relative to the vowel harmonic (Experiment 1), or introducing a silent interval from 0 to 320 ms between the precursor and the vowel (Experiment 2), both produce effects on vowel quality consistent with those predicted from peripheral adaptation or recovery from it. However, there were some listeners for whom even the smallest gap largely eliminated the effect of the precursor. Consistent with the inhibitory account of the restoration effect, a contralateral pure tone whose frequency is close to that of the precursor is highly effective at restoring the contribution of the asynchronous harmonic (Experiment 3). When the frequencies match, lateralization cues arising from binaural fusion of the precursor and contralateral tone may also contribute to this restoration.

Pyrazolylborates and their importance in tuning single-molecule magnet properties of {Fe(III)2Ni(II)} complexes.

A new tricyanoferrate(III) building block and a trinuclear single-molecule magnet derivative are described. The treatment of a 2:1 ratio of [NEt(4)][(Tp*(Bn))Fe(III)(CN)(3)]·H(2)O·MeOH [1; Tp*(Bn) = tris(3,5-dimethyl-4-benzyl)pyrazolylborate] with nickel(II) trifluoromethanesulfonate gives {[(Tp*(Bn))Fe(III)(CN)(3)](2)[Ni(II)(DMF)(4)]}·2DMF (2; DMF = N,N-dimethylformamide). The symmetry-equivalent Fe(III)(LS) ions lead to a favorable alignment of anisotropy tensors (i.e., Fe···B axes) in 2, and an energy barrier of Δ(eff)/k(B) = 16.7 K is found for the S(T) = 2 complex.

Irreversible solvent-driven conversion in cyanometalate {Fe2Ni}n (n=2, 3) single-molecule magnets.

Two cyano-bridged single-molecule magnets of {Fe(III)(4)Ni(II)(2)} and {Fe(III)(6)Ni(II)(3)} stoichiometry are described via their magnetic properties described in the frame of geometrical core distortions and orientations of their local anisotropy axes.

Synthesis and characterization of di- and trivalent pyrazolylborate ß-diketonates and cyanometalates.

The syntheses, structures, and magnetic properties of a series of di- and trivalent hydridotris(3,5-dimethylpyrazol-1-yl)borate (Tp*) cyanomanganates are described. Treatment of tris(acetylacetonate)manganese(III) [Mn(acac)(3)] with KTp* and tetra(ethyl)ammonium cyanide affords [NEt(4)][(Tp*)Mn(II)(κ(2)-acac)(CN)] (1), as the first monocyanomanganate(II) complex; attempted oxidation of 1 with iodine affords {(Tp*)Mn(II)(κ(2)-acac(3-CN))}(n) (2) as a one-dimensional chain and bimetallic {[NEt(4)][(Tp*)Mn(II)(κ(2)-acac(3-CN))](2)(µ-CN) (3) as the major and minor products, respectively. A fourth complex, [NEt(4)][(Tp*)Mn(II)(η(2)-acac(3-CN))(η(1)-NC-acac)] (4), is obtained via treatment of Mn(acac(3-CN))(3) with KTp* and [NEt(4)]CN, while [NEt(4)](2)[Mn(II)(CN)(4)] (5) was prepared from manganese(II) trifluoromethanesulfonate and excess [NEt(4)]CN. Tricyanomanganate(III) complexes, [cat][(Tp*)Mn(III)(CN)(3)] [cat = NEt(4)(+), 7; PPN(+), 8], are prepared via sequential treatment of Mn(acac(3-CN))(3) with KTp*, followed by [NEt(4)]CN, or [cat](3)[Mn(III)(CN)(6)] with (Tp*)SnBu(2)Cl. Magnetic measurements indicate that 1, 2, and 4 contain isotropic Mn(II) (S = (5)/(2); g = 2.00) centers, and no long-range magnetic ordering is found above 1.8 K. Compounds 7 and 8 contain S = 1 Mn(III) centers that adopt singly degenerate spin ground states without orbital contributions to their magnetic moments.

Lumbar spinal stenosis with exacerbation of back pain with extension: a potential contraindication for supine MRI with sedation.

A 71-year-old male with lumbar spinal stenosis developed exacerbation of lower back pain and leg paresthesias while attempting to undergo a spinal magnetic resonance imaging (MRI) scan in the supine position. After undergoing sedation for the MRI, he developed an acute cauda equina syndrome that required surgical decompression. MRI may be contraindicated in the supine position for patients with spinal stenosis and back pain exacerbated by mild-to-moderate extension, since it may further compress the neural tissue.

A cyano-based octanuclear {Fe(III)(4)Ni(II)(4)} single-molecule magnet.

A new low symmetry octanuclear cyano-based {Fe(III)(4)Ni(II)(4)} single-molecule magnet (SMM) is described. This SMM exhibits the highest energy barrier (Delta/k(B) approximately 33 K) for magnetization reversal seen for any first-row cyanide-based complex. The importance of anisotropy axes alignment and their impact on SMM properties are illustrated when cubic {Fe(III)(4)Ni(II)(4)} boxes are compared to octanuclear complexes of lower overall symmetry.