4 research outputs found
Myxofibrosarcoma of the thyroid gland
AbstractIntroductionMyxofibrosarcoma of the thyroid is exceptional: a Medline search found a single case report. We report a new case which raised diagnostic and therapeutic problems.ObservationWe report the case of a 74-year-old woman who presented with swelling of the left thyroid lobe and ipsilateral cervical lymphadenopathy. Total thyroidectomy with cervical lymph-node dissection was performed. Histological analysis diagnosed myxofibrosarcoma. Evolution was marked by rapid local recurrence, and chemotherapy based on doxorubicin and ifosfamide was introduced.Discussion/conclusionHead and neck myxofibrosarcoma is rare. MRI is essential and should always precede treatment. Diagnosis is histological. There is elevated risk of local recurrence after resection, accompanied by worsening tumor grade, whence the need for accurate diagnosis, appropriate treatment and regular MRI follow-up
Prototypical Organic–Oxide Interface: Intramolecular Resolution of Sexiphenyl on In<sub>2</sub>O<sub>3</sub>(111)
The performance of
an organic semiconductor device is critically determined by the geometric
alignment, orientation, and ordering of the organic molecules. Although
an organic multilayer eventually adopts the crystal structure of the
organic material, the alignment and configuration at the interface
with the substrate/electrode material are essential for charge injection
into the organic layer. This work focuses on the prototypical organic
semiconductor para-sexiphenyl (6P) adsorbed on In<sub>2</sub>O<sub>3</sub>(111), the thermodynamically most stable surface of the material
that the most common transparent conducting oxide, indium tin oxide,
is based on. The onset of nucleation and formation of the first monolayer
are followed with atomically resolved scanning tunneling microscopy
and noncontact atomic force microscopy (nc-AFM). Annealing to 200
°C provides sufficient thermal energy for the molecules to orient
themselves along the high-symmetry directions of the surface, leading
to a single adsorption site. The AFM data suggests an essentially
planar adsorption geometry. With increasing coverage, the 6P molecules
first form a loose network with a poor long-range order. Eventually,
the molecules reorient into an ordered monolayer. This first monolayer
has a densely packed, well-ordered (2 × 1) structure with one
6P per In<sub>2</sub>O<sub>3</sub>(111) substrate unit cell, that
is, a molecular density of 5.64 × 10<sup>13</sup> cm<sup>–2</sup>
Metal Tungstates at the Ultimate Two-Dimensional Limit: Fabrication of a CuWO<sub>4</sub> Nanophase
Metal tungstates (with general formula MWO<sub>4</sub>) are functional materials with a high potential for a diverse set of applications ranging from low-dimensional magnetism to chemical sensing and photoelectrocatalytic water oxidation. For high level applications, nanoscale control of film growth is necessary, as well as a deeper understanding and characterization of materials properties at reduced dimensionality. We succeeded in fabricating and characterizing a two-dimensional (2-D) copper tungstate (CuWO<sub>4</sub>). For the first time, the atomic structure of an ultrathin ternary oxide is fully unveiled. It corresponds to a CuWO<sub>4</sub> monolayer arranged in three sublayers with stacking O–W–O/Cu from the interface. The resulting bidimensional structure forms a robust framework with localized regions of anisotropic flexibility. Electronically it displays a reduced band gap and increased density of states close to the Fermi level with respect to the bulk compound. These unique features open a way for new applications in the field of photo- and electrocatalysis, while the proposed synthesis method represents a radically new and general approach toward the fabrication of 2-D ternary oxides
Water Structures Reveal Local Hydrophobicity on the In<sub>2</sub>O<sub>3</sub>(111) Surface
Clean oxide surfaces are generally hydrophilic. Water
molecules
anchor at undercoordinated surface metal atoms that act as Lewis acid
sites, and they are stabilized by H bonds to undercoordinated surface
oxygens. The large unit cell of In2O3(111) provides
surface atoms in various configurations, which leads to chemical heterogeneity
and a local deviation from this general rule. Experiments (TPD, XPS,
nc-AFM) agree quantitatively with DFT calculations and show a series
of distinct phases. The first three water molecules dissociate at
one specific area of the unit cell and desorb above room temperature.
The next three adsorb as molecules in the adjacent region. Three more
water molecules rearrange this structure and an additional nine pile
up above the OH groups. Despite offering undercoordinated In and O
sites, the rest of the unit cell is unfavorable for adsorption and
remains water-free. The first water layer thus shows ordering into
nanoscopic 3D water clusters separated by hydrophobic pockets