Far-infrared spectroscopy and X-ray diffraction Rietveld structure-refinement of synthetic kinoshitalite (Kn) solid solutions, BaMg3(Al2-xGax)(Si2-yGey)O10(OH,OD,F)2: (x=0.0-2.0, y=0.0-2.0), show ...that there is complete solid solution for all compositions in each (OH/OD)- and F-series: 4Al2(Si2-yGey)-, 4(Al2-xGax)Si2-, 4Ga2(Si2-yGey)-, 4(Al2-xGax)Ge2-Kn, and in OH/OD-for-F substituted 4(Al2Si2)-, 4(Ga2Si2)-, 4(Al2Ge2)-, 4(Ga2Ge2)-Kn end-member compositions. In the far-infrared region, 170-40 cm-1, three kind of bands are observed; an in-plane tetrahedral torsional mode, an interlayer Ba-Oinner stretching vibration and a Ba-Oouter stretching vibration. With increasing tetrahedral 4Al-for-4Ga and Si-for-Ge substitution, the frequencies and intensities of the tetrahedral in-plane torsional bands decrease in both the (OH/OD)- and F-bearing phases, but in the 4(Al2Si2)-, 4(Ga2Si2)-, 4(Al2Ge2)-, 4(Ga2Ge2)-Kn end-member compositions, the frequencies are unaffected by (OH/OD)-for-F substitution. The frequencies of both the Ba-Oinner and Ba-Oouter stretching bands increase with increasing 4Al-for-4Ga and Si-for-Ge substitution, but the frequencies of the Ba-Oinner stretching bands decrease with increasing (OH/OD)-for-F substitution in the 4(Al2Si2)-, 4(Ga2Si2)-, 4(Al2Ge2)-, 4(Ga2Ge2)-Kn end-member compositions. The frequency difference between the Ba-Oinner and Ba-Oouter stretching bands is linearly related to the tetrahedral rotation angles (α), and these differences are about 10 cm-1 larger in the (OH/OD)-bearing phases than in the corresponding F-bearing phases. The ranges of absorption frequencies and their corresponding deformation modes are as follows: (1) in-plane tetrahedral torsional mode, 105-150 cm-1; (2) Ba-Oinner stretching vibration, 105-140 cm-1; and (3) Ba-Oouter stretching vibration, 75-90 cm-1.
The classification and nomenclature of mineral species is regulated by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association (IMA-CNMNC). This ...mineral species classification is necessary for Earth Sciences, as minerals constitute most planetary and interstellar materials.
has proposed a classification of minerals and other Earth and planetary materials according to “natural clustering.” Although this classification is complementary to the IMA-CNMNC mineral classification and is described as such, there are some unjustified criticisms and factual errors in the comparison of the two schemes. It is the intent of the present comment to (1) clarify the use of classification schemes for Earth and planetary materials, and (2) counter erroneous criticisms or statements about the current IMA-CNMNC system of approving proposals for new mineral species and classifications.
Gisèle d'Estoc was the pseudonym of a nineteenth-century French woman writer and, it turns out, artist who, among other things, was accused of being a bomb-planting anarchist, the cross-dressing ...lover of writer Guy de Maupassant, and the fighter of at least one duel with another woman, inspiring Bayard's famous painting on the subject. The true identity of this enigmatic woman remained unknown and was even considered fictional until recently, when Melanie C. Hawthorne resurrected d'Estoc's discarded story from the annals of forgotten history.
Finding the Woman Who Didn't Existbegins with the claim by expert literary historians of France on the eve of World War II that the woman then known only as Gisèle d'Estoc was merely a hoax. More than fifty years later, Hawthorne not only proves that she did exist but also uncovers details about her fascinating life and career, along the way adding to our understanding of nineteenth-century France, literary culture, and gender identity. Hawthorne explores the intriguing life of the real d'Estoc, explaining why others came to doubt the "experts" and following the threads of evidence that the latter overlooked. In focusing on how narratives are shaped for particular audiences at particular times, Hawthorne also tells "the story of the story," which reveals how the habits of thought fostered by the humanities continue to matter beyond the halls of academe.
Unsatisfactory failure rates following rotator cuff (RC) repair have led orthopaedic surgeons to explore biological augmentation of the healing enthesis. The subacromial bursa (SB) contains abundant ...connective tissue progenitor cells (CTPs) that may aid in this process. The purpose of the study was to investigate the influence of patient demographics and tear characteristics on the number of colony-forming units (CFUs) and nucleated cell count (NCC) of SB-derived CTPs. In this study, we harvested SB tissue over the supraspinatus tendon and muscle in 19 patients during arthroscopic RC repair. NCC of each sample was analyzed on the day of the procedure. After 14 days, CFUs were evaluated under a microscope. Spearman’s rank correlation coefficient was then used to determine the relationship between CFUs or NCC and patient demographics or tear characteristics. The study found no significant correlation between patient demographics and the number of CFUs or NCC of CTPs derived from the SB (p > 0.05). The study did significantly observe that increased tear size was negatively correlated with the number of CFUs (p < 0.05). These results indicated that increased tear size, but not patient demographics, may influence the viability of CTPs and should be considered when augmenting RCrepairs with SB.
To investigate the presence of connective tissue progenitor cells (CTPs) in the trochanteric bursa harvested over the gluteus medius muscle belly and tendon during open hip procedures.
Trochanteric ...bursa samples from nine patients (63.1 ± 8.6 years) undergoing total hip arthroplasty for primary osteoarthritis were obtained from 2 sites: over the gluteus medius tendon at the greater trochanter and over the muscle belly. Bursal tissue was digested with collagenase and grown in culture. The nucleated cell count, cellular concentration, cellular proliferation, fluorescence-activated cell sorting (FACS) analysis, and differentiation using immunostaining and quantitative polymerase chain reaction (PCR) were used to determine and quantify the presence of CTPs.
Bursa-derived CTPs were identified in all harvested samples. At t = 0, there was no difference in nucleated cell count over muscle and tendon (1.69 ± 1.26 × 108 and 1.41 ± 1.12 × 108 cells/g, respectively; P = .162). Similarly, the cellular concentration at 3 weeks was not significantly different between bursa harvested over muscle and tendon (6.61 ± 5.14 × 106 and 5.58 ± 4.70 × 106 cells/g, respectively; P = .532). High cellular proliferation was identified for both bursal tissue overlying muscle and tendon (2.28 ± .95 and 1.66 ± 1.05, respectively; P = .194). FACS analysis revealed high positivity rates (>95%) of CTP-specific surface epitopes (CD105, CD90, and CD73) and low positivity rates (<1.3%) of negative markers (CD45, CD31). Osteogenic, adipogenic, and chondrogenic differentiation potential was demonstrated with immunostaining and quantitative PCR for gene expression.
Connective tissue progenitor cells are found in the trochanteric bursa overlying the muscle and tendon of the hip abductors.
During open hip procedures, the trochanteric bursa is often partially excised to identify muscular boundaries and tissue planes for surgical exposure. The function of the trochanteric bursa remains largely unknown. However, this tissue is a source of connective tissue progenitor cells, which may be important in the healing response of surgically repaired abductor tendons.
Eight turquoise samples covering a wide range of compositions in the turquoise-chalcosiderite solid-solution series were analyzed by Mossbauer spectroscopy, X-ray diffraction (XRD), electron ...microprobe analysis (EMPA), and Fourier transform infrared (FTIR) spectroscopy. Two of the turquoise samples display evidence of alteration from weathering processes. The unit formulas were calculated on the basis of 24 (O,OH) anions and 11 cations using the results of EMPA, assuming all Fe as Fe3+, as confirmed by Mossbauer spectroscopy. The altered turquoise samples show deficiencies in both cations and anion groups, indicated by EMPA, but they preserve the crystal structure of turquoise, as verified by XRD. They also show large amounts of Si and Ca in their microprobe data, due to the presence of kaolinite and Ca carbonate, respectively, which are identified by FTIR spectroscopy. The isomorphous substitution of Fe3+ for Al in the turquoise structure broadens and shifts the IR bands to lower frequencies, in particular the OH-stretching bands. The Mossbauer spectra, collected at room temperature, are fitted with two generalized Fe3+ sites, using a Voigt-based quadrupole-splitting distribution method, which are assigned to the M3 (smaller quadrupole splitting) on the one hand and M1 and M2 octahedral sites on the other hand. The Fe3+ distribution over the M3 and M1,2 sites, calculated from the Mossbauer relative areas and EMPA, indicates that Fe3+ prefers the larger M3 octahedron in the turquoise-chalcosiderite solid-solution series.
Agakhanovite-(Y), ideally (YCa)2KBe3Si12O30, is a new milarite-group mineral from the Heftetjern pegmatite, Tordal, southern Norway. Crystals are prismatic along 001, and show the forms {100} and ...{100}. Agakhanovite-(Y) is colorless with a white streak and a vitreous luster, and does not fluoresce under ultraviolet light. There is no cleavage or parting, and no twinning was observed. Mohs hardness is 6, and agakhanovite-(Y) is brittle with a conchoidal fracture. The calculated density is 2.672 g/cm3. Optical properties were measured with the Bloss spindle stage for the wavelength 590 nm using a gel filter. Agakhanovite-(Y) is uniaxial (-) with indices of refraction ω = 1.567, ε = 1.564, both ±0.002; the calculated birefringence is 0.003 and it is non-pleochroic. Agakhanovite-(Y) is hexagonal, space group P6/mcc, a = 10.3476(2), c = 13.7610(3) Å, V = 1276.02(9) Å3, Z = 2, c:a = 1.330. The seven strongest lines in the X-ray powder-diffraction pattern are as follows: d (Å), I, (hkl): 2.865, 100, (124); 3.287, 96, (131); 4.134, 84, (122); 6.877, 56, (002); 2.986, 43, (030); 4.479, 38, (020); 2.728, 36, (024). Chemical analysis by electron microprobe gave SiO2 69.56, Al2O3 0.35, Y2O3 9.69, Yb2O3 0.15, FeO 0.02 CaO 5.75, Na2O 0.07, K2O 4.52, BeO(calc) 7.06, H2O(calc) 1.74, sum 98.91 wt%. The H2O content was determined by crystal-structure analysis. On the basis of 30 anions, the empirical formula is (Y0.89Yb0.01Ca1.06)Σ1.96(H2O)0.92Na0.02K1.00 (Be2.93Al0.07)Σ3.00Si12.02O30. The crystal structure of agakhanovite-(Y) was refined to an R1 index of 1.9% based on 660 unique observed reflections collected on a three-circle rotating-anode (MoKα X-radiation) diffractometer equipped with multilayer optics and an APEX-II detector. In the end-member structure of agakhanovite-(Y), the A site is occupied equally by Y and Ca, and the B site is vacant; agakhanovite-(Y) is the Y-analog of oftedalite: ScCa2KBe3Si12O30, and the Y-Ca-Be analog of klochite, (Fe2+Fe3+)2KZn3Si12O30.
PDF
