Lewis Acidic Aluminosilicates: Synthesis, 27Al MQ/MAS NMR, and DFT-Calculated 27Al NMR Parameters.

Porous aluminosilicates are functional materials of paramount importance as Lewis acid catalysts in the synthetic industry, yet the participating aluminum species remain poorly studied. Herein, a series of model aluminosilicate networks containing [L-AlO3] (L = THF, Et3N, pyridine, triethylphosphine oxide (TEPO)) and [AlO4]- centers were prepared through nonhydrolytic sol-gel condensation reactions of the spherosilicate building block (Me3Sn)8Si8O20 with L-AlX3 (X = Cl, Me, Et) and [Me4N] [AlCl4] compounds in THF or toluene. The substoichiometric dosage of the Al precursors ensured complete condensation and uniform incorporation, with the bulky spherosilicate forcing a separation between neighboring aluminum centers. The materials were characterized by 1H, 13C, 27Al, 29Si, and 31P MAS NMR and FTIR spectroscopies, ICP-OES, gravimetry, and N2 adsorption porosimetry. The resulting aluminum centers were resolved by 27Al TQ/MAS NMR techniques and assigned based on their spectroscopic parameters obtained by peak fitting (δiso, CQ, η) and their correspondence to the values calculated on model structures by DFT methods. A clear correlation between the decrease in the symmetry of the Al centers and the increase of the observed CQ was established with values spanning from 4.4 MHz for distorted [AlO4]- to 15.1 MHz for [THF-AlO3]. Products containing exclusively [TEPO-AlO3] or [AlO4]- centers could be obtained (single-site materials). For L = THF, Et3N, and pyridine, the [AlO4]- centers were formed together with the expected [L-AlO3] species, and a viable mechanism for the unexpected emergence of [AlO4]- was proposed.

Dynamic ultrasound in the evaluation of patients with suspected slipping rib syndrome.

OBJECTIVE: Slipping rib syndrome (SRS) affects adolescents and young adults. Dynamic ultrasound plays a potential and likely significant role; however, limited data exist describing the protocol and techniques available. It is our intent to describe the development of a reproducible protocol for imaging in patients with SRS. MATERIALS AND METHODS: Retrospective review of suspected SRS patients from March 2017 to April 2018. A total of 46 patients were evaluated. Focused history and imaging was performed at the site of pain. Images of the ribs were obtained in the parasagittal plane at rest and with dynamic maneuvers. Dynamic maneuvers included Valsalva, crunch, rib push maneuver, and any provocative movement that elicited pain. Imaging was compared with records from the pediatric surgeon specializing in slipping ribs. Statistical analysis was performed. RESULTS: Thirty-six of the 46 patients had a diagnosis of SRS, and had an average age of 17 years. Thirty-one patients were female, 15 were male. Thirty-one out of 46 (67%) were athletes. Average BMI was 22.6. Dynamic ultrasound correctly detected SRS in 89% of patients (32 out of 36) and correctly detected the absence in 100% (10 out of 10). Push maneuver had the highest sensitivity (87%; 0.70, 0.96) followed by morphology (68%; 0.51, 0.81) and crunch maneuver (54%; 0.37, 0.71). Valsalva was the least sensitive (13%; 0.04, 0.29). CONCLUSION: Dynamic ultrasound of the ribs, particularly with crunch and push maneuvers, is an effective and reproducible tool for diagnosing SRS. Valsalva plays a limited role. In addition to diagnosing SRS, ultrasound can give the surgeon morphological data and information on additional ribs at risk, thereby assisting in surgical planning.

Retropharyngeal edema: an unusual manifestation of Kawasaki disease.

BACKGROUND: Kawasaki disease (KD) is an acute multisystem vasculitis of unknown etiology that typically affects young children. KD presenting as a retropharyngeal inflammatory process is very rare. OBJECTIVES: To report a case of KD initially presenting as a retropharyngeal edema mimicking a deep neck infection, and to review previously published reports in the literature. CASE REPORT: We report a case of KD in a previously healthy 3-year-old child who presented with acute onset of fever and cervical adenitis, along with computed tomography scan findings of retropharyngeal edema and inflammation. KD was suspected due to persistent fever and no improvement in the patient's condition despite appropriate antibiotic therapy; and other classic findings of KD eventually developed. An echocardiogram obtained on the 10th day of illness revealed pericardial effusion but no coronary ectasia or aneurysm. Treatment with high-dose intravenous immunoglobulin resulted in dramatic clinical improvement. Follow-up echocardiograms obtained 2 and 8 weeks after discharge revealed a small left coronary artery aneurysm (CAA). Nine months later, the CAA had resolved and the patient was well with no sequelae. CONCLUSIONS: Although unusual, physicians should be aware of retropharyngeal edema as an atypical presentation of KD.

119Sn NMR chemical shift tensors in anhydrous and hydrated Si8O20(SnMe3)8 crystals.

(119)Sn chemical shift tensors of crystalline trialkyltin functionalized octameric spherosilicates, Si(8)O(20)(SnMe(3))(8), have been determined by fitting sideband intensities in solid-state magic angle spinning (MAS) NMR spectra. Tin chemical shift parameters are exquisitely sensitive to the presence of water of crystallization. Both hydrogen bonding and incipient oxygen-tin bonding from molecular water impact the local tin environment. Tin chemical shift tensors in the crystalline derivatives reflect the changes in geometry and coordination number at the tin centers. Chemical shift correlations on the crystalline derivatives, with known x-ray structures, are used to infer the tin coordination environment in an amorphous sample.

MR urography: techniques and clinical applications.

Magnetic resonance (MR) urography comprises an evolving group of techniques with the potential for allowing optimal noninvasive evaluation of many abnormalities of the urinary tract. MR urography is clinically useful in the evaluation of suspected urinary tract obstruction, hematuria, and congenital anomalies, as well as surgically altered anatomy, and can be particularly beneficial in pediatric or pregnant patients or when ionizing radiation is to be avoided. The most common MR urographic techniques for displaying the urinary tract can be divided into two categories: static-fluid MR urography and excretory MR urography. Static-fluid MR urography makes use of heavily T2-weighted sequences to image the urinary tract as a static collection of fluid, can be repeated sequentially (cine MR urography) to better demonstrate the ureters in their entirety and to confirm the presence of fixed stenoses, and is most successful in patients with dilated or obstructed collecting systems. Excretory MR urography is performed during the excretory phase of enhancement after the intravenous administration of gadolinium-based contrast material; thus, the patient must have sufficient renal function to allow the excretion and even distribution of the contrast material. Diuretic administration is an important adjunct to excretory MR urography, which can better demonstrate nondilated systems. Static-fluid and excretory MR urography can be combined with conventional MR imaging for comprehensive evaluation of the urinary tract. The successful interpretation of MR urographic examinations requires familiarity with the many pitfalls and artifacts that can be encountered with these techniques.

Soft tissue amyloidoma of the extremities: a case report and review of the literature.

The deposition of amyloid as a distinct, clinically apparent mass is uncommon, particularly in soft tissues. Among reported sites of soft tissue amyloidomas, the extremities are quite rare. Amyloid tumors can mimic malignant neoplasms both clinically and radiologically. We report a case of AA amyloidoma presenting in the deltoid region with radiological features suggesting sarcoma. Cytomorphology from fine-needle aspiration material, tissue histology, and appearance by magnetic resonance imaging are described. The literature on soft tissue amyloidoma is reviewed.

Building block syntheses of site-isolated vanadyl groups in silicate oxides.

Cross-linking of the cubic silicate building block, Si8O20 with vanadyl chloride leads to porous solids in which a homogeneous dispersion of isolated vanadyl groups is maintained throughout the matrix even at high loadings of vanadium.

Mechanistic investigation of hydrolysis reactions of dithioacetal derivatives grafted on silica gels.

Silica gels believed to be grafted with dithioacetal derivatives were recently used for Hg(II) extraction, and were found to selectively remove 94-100% of Hg(2+) ions from metal ion mixtures. The current studies with one derivative suggest that the functional group in the Hg(II) removal is the mercapto (SH) ligand. The dithioacetal group in (ClCOCH(2)S)(2)CHPh (2) was hydrolyzed during its reaction with amine (O)(3)Si(CH(2))(3)NH(2) (3) grafted on silica gel to give the mercapto ligand (O)(3)Si(CH(2))(3)NHCOCH(2)SH (4). The silica gel grafted with the mercapto ligand 4 selectively removed Hg(2+) ions with reported high capacities.

Ionic liquids: a new class of sensing materials for detection of organic vapors based on the use of a quartz crystal microbalance.

A QCM device employing ionic liquids as the sensing materials for organic vapors has been developed and evaluated. The sensing mechanism is based on the fact that the viscosity of the ionic liquid membrane decreases rapidly due to solubilization of analytes in the ionic liquids. This change in viscosity, which varies with the chemical species of the vapors and the types of ionic liquids, results in a frequency shift of the corresponding quartz crystal. The QCM sensor demonstrated a rapid response (average response time of less than 2 s) to organic vapors with an excellent reversibility because of the fast diffusion of analytes in ionic liquids. Furthermore, the ionic liquids, with zero vapor pressure and stable chemical properties, ensure a long-term shelf life for the sensor.

Imprint Coating: A Novel Synthesis of Selective Functionalized Ordered Mesoporous Sorbents.

Molecular imprinting of surfaces of mesoporous sorbents is a novel method for introducing template-selective recognition sites. This method makes use of the unique surface environment of hexagonally packed mesopore surfaces of selected pore sizes (see the schematic representation) and coats such surfaces with functional ligands by binding to a metal ion template.

Diffusional and Internal Rotation in Single and Linked Trinuclear Bis(carbyne) Cluster Complexes Determined by (13)C NMR Relaxation Time Measurements.

Carbon-13 NMR relaxation times have been measured as a function of temperature for a family of bis(carbyne) cluster complexes: (CpCo)(3)(&mgr;(3)-CPh)(2) (1a), (CpCo)(3)(&mgr;(3)-CH)(&mgr;(3)-CPh) (1b), and X(1,4-C(6)H(4))Y with X = Y = (CpCo)(3)(&mgr;(3)-CPh)(&mgr;(3)-C-) (2); X = (CpCo)(3)(&mgr;(3)-CPh)(&mgr;(3)-C-), Y = -C&tbd1;CPh (3); or X = Y = -C&tbd1;CPh (4). These molecules can be regarded as symmetric top molecules in which the phenyl rings are adjacent to zero, one, or two Cp(3)Co(3) metal cluster units. Molecular rotational diffusion coefficients about the different axes of the molecules (D( perpendicular)and D(s)) obtained from the relaxation times indicate that the motions of the molecules are highly anisotropic. Rapid internal rotation of the phenyl rings described by the rotation rates R contributes significantly to that anisotropy. Phenyl rings adjacent to an alkyne group rotate at a rate comparable to that of free benzene whereas phenyl rings bound to a (CpCo)(3) group through a &mgr;(3)-carbyne ligand show significantly reduced rates of rotation. The observed difference in rotation rates is believed to be due primarily to steric interactions between phenyl rings and their substituents.