Iron(II) octaethyltetraazaporphyrin has been discovered to exist as two polymorphs at room temperature, α- and β-Fe(OETAP). This has been established by X-ray powder diffraction and scanning electron ...microscopy. Both ac and dc SQUID magnetometry show that the α phase is a soft molecular ferromagnet with T Curie = 2.8 K. The β phase possesses the same number of unpaired spins and a similar g value, but it does not order above ∼1 K. Zero-field splitting is likely competing with ferromagnetic coupling in this compound. 57Fe Mössbauer spectroscopy has been used to support the local structural similarity between the two phases and to study the ferromagnetic transition. The isomorphous manganese analogue of α-Fe(OETAP), α-Mn(OETAP), expected to be a ferromagnet with a higher T Curie, exhibits many characteristics of ferromagnetism, notably hysteresis at 1.8 K with H coer = 2.5 kG and M rem = 4 kemu-G/mol. However, in contrast to ferromagnetic α-Fe(OETAP), α-Mn(OETAP) shows strongly frequency-dependent ac susceptibility in the range from 1 to 1000 Hz, indicating that it exists in a spin-glass-like state. This result underscores the need for frequency-dependent ac magnetometry to fully characterize ferromagnetic molecular materials.
With the growing number of fatalities resulting from the 100 or so cancer-related diseases, new enabling tools are required to provide extensive molecular profiles of patients to guide the clinician ...in making viable diagnosis and prognosis. Unfortunately with cancer-related diseases, there is not one molecular marker that can provide sufficient information to assist the clinician in making effective prognoses or even diagnoses. Indeed, large panels of markers must typically be evaluated that cut across several different classes (mutations in certain gene fragments—DNA; over/under-expression of gene activity as monitored by messenger RNAs; the amount of proteins present in serum or circulating tumor cells). The classical biosensor format (dipstick approach for monitoring the presence of a single element) is viewed as a valuable tool in many bioassays, but possesses numerous limitations in cancer due primarily to the single element nature of these sensing platforms. As such, if biosensors are to become valuable tools in the arsenal of the clinician to manage cancer patients, new formats are required. This review seeks to provide an overview of the current thinking on molecular profiling for diagnosis and prognosis of cancers and also, provide insight into the current state-of-the-art in the biosensor field and new strategies that must be considered to bring this important technology into the cancer field.
Rapid advances in telehealth development and adoption are increasing the spectrum of information and communication technologies that can be applied not only to individual patient care but more ...broadly to population health as well. Participants in this breakout session were asked to address, from their diverse perspectives, a series of questions relating to the current and potential uses of telehealth applications and networks for public health and emergency/disaster preparedness and response systems. Participants identified several gaps in current understanding and research emphasis. There is a clear need for more and larger outcome studies to assess the impact and cost benefit of telehealth applications in terms of improving public health at the population and community levels. In addition, more research is needed to demonstrate the ability of telehealth tools and technologies to facilitate and extend the reach of major national clinical and public health research initiatives. Perhaps most importantly, the National Institutes of Health should develop and/or strengthen strategic partnerships with other funding agencies with overlapping or complementary interests to accelerate interdisciplinary research in this rapidly evolving but relatively understudied and complex field.
The 17-electron complex (C5Ph5)Cr(CO)3 reacts with halogens (C6H5I·Cl2, Br2, and I2) in C6H6 to yield the dimeric oxidation products (C5Ph5)Cr(μ-X)X2 as thermally stable solids. Reactions with other ...chlorinating agents similarly yield (C5Ph5)CrCl22. An X-ray crystal structure of (C5Ph5)Cr(μ-Cl)Cl2 was obtained. The magnetic properties of the Cl2-bridged dimer have been determined and modeled using the usual isotropic Hamiltonian H = −2J Ŝ 1·Ŝ 2, which yields J/k = −30 K. Low-temperature (77 K) Raman spectra of solid (C5Ph5)CrX22 (X = Cl, I) allow assignments to be made for the metal-ring and metal halogen stretching modes in the low-frequency region (<600 cm-1). Tetrahydrofuran (THF) cleaves these dimers to yield complexes of the form (C5Ph5)CrX2(THF).
The magnetic properties of first-row transition metal complexes of octaethyltetraazaporphyrin (M$\sp{2+}$OETAP, where M = Mn, Fe, Co, Cu, and Ni) were investigated utilizing SQUID magnetometry. ...Measurements of the temperature and field dependence of susceptibility and magnetization were used to study the nature of exchange interactions in each compound. Suitable models were employed to estimate the magnitude of the coupling constant, J. Magnetic measurements indicate that FeOETAP possesses an intermediate S = 1 ground state as is found in related four-coordinate Fe(II) porphyrin compounds. Low temperature and low field studies indicate the presence of ferromagnetic interactions in FeOETAP that ultimately lead to three-dimensional ordering below T$\sb{\rm c}$ = 2.8 K. The value of the saturation magnetization indicates that the spins are canted in the ordered state. Application of a one-dimensional Ising model incorporating zero-field splitting results in an estimate of the coupling constant (J/k = 5 K) and zero-field splitting constant (D/k = 7 K). The zero-field splitting in FeOETAP is nearly an order of magnitude smaller than in related four-coordinate Fe(II) porphyrin systems in which no exchange interactions are observed. A different phase of FeOETAP has been prepared which demonstrates only zero-field splitting, from which a value of D = 11 K is obtained (assuming S = 1). Powder diffraction measurements indicate that the ordering and non-ordering FeOETAP compounds are different phases. MnOETAP also possesses an intermediate (S = 3/2) ground state as observed in the related Mn(II) phthalocyanine compound. But unlike both MnPc and FeOETAP which undergo cooperative ordering, MnOETAP exhibits spin-glass behavior as observed by a frequency dependence of the ac susceptibility. This is explained by a smaller effective exchange coupling which results in frustration in the canted spin lattice. Powder diffraction results indicate that the spin-glass-like MnOETAP compound crystallizes in the same structure as the ordering FeOETAP. A separate MnOETAP phase has been found in which exchange interactions are absent. The structure of this phase was found to be isomorphous to the FeOETAP phase demonstrating only zero-field-splitting. CoOETAP and CuOETAP exhibit weak antiferromagnetic interactions whereas NiOETAP is diamagnetic as expected. Intermolecular exchange between spins on the metal centers in these systems can be explained via superexchange through the $\pi$-orbital system of the planar porphyrin ring or alternatively by overlap of regions of positive and negative spin density.
We report on the magnetic properties of the molecular solids derived from square-planar, neutral iron(II) octaethyltetraazaporphyrin, FeOETAP. This compound exists as two polymorphs, α and β. dc ...SQUID and ac susceptometry measurements (1-1000 Hz) show that the α polymorph orders as a soft molecular ferromagnet below T
Curie
= 2.8 K, whereas the β form, with the same number of unpaired spins and a similar g value, exhibits zero-field splitting to a non-magnetic ground state.
57
Fe-Mössbauer spectroscopy indicates that α-FeOETAP exhibits a remarkably large internal hyperfine field, H
int
, of 62.4 T. This, to our knowledge, is the highest value of H
int
ever reported for Fe, regardless of its spin state.
Described here is an ultrasound technique used to study tongue movements, particularly lateral tongue movements, during mastication. A method to analyze spatial and temporal tongue movements was ...developed, and the feasibility of using this method was evaluated. Biplane ultrasound images of tongue movements of four adults without oral motor disability and two adults with oral motor disability as a result of cerebral palsy, were acquired. Tongue movements were analyzed in the coronal and sagittal planes using B-mode and M-mode ultrasonography. Inter-rater and intra-rater agreement for manual tracing of tongue contours was good (ICC = 0.81 and 0.84, respectively). There were significant differences between the two adult groups in movement frequency in the horizontal direction in both coronal and sagittal planes. In the coronal plane, differences in movement frequency and range of vertical movement were detected. Data obtained from sagittal images, with the exception of vertical frequency, indicated no differences between the groups. The protocol developed in this study (using B-mode and M-mode) proved to be valid and reliable. By using this protocol with individuals with and without oral motor disability, we were able to illustrate the clinical application of our protocol to evaluation of differences in tongue movements during mastication.
She lists practical reasons for a VBAC: the baby is more likely to be bigger, have healthy lungs, have earlier contact with their mothers, and is more likely to be breastfed. The mother can expect a ...shorter recovery time, feel more attached to her baby sooner, and have a lower risk of post-partum infection. Diana Korte also addresses women's fears of having a VBAC, such as a ruptured C-section scar (the incidence is fairly low) and not being able to deliver a baby vaginally. Korte also refutes the idea that many women's pelvis width is `too small,' adding that doctors' predictions of a baby's size aren't usually accurate.
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