6 research outputs found
Asymptomatic stage I sarcoidosis complicated by pulmonary tuberculosis: a case report
<p>Abstract</p> <p>Introduction</p> <p>Sarcoidosis is a multisystem granulomatous disorder characterized pathologically by the presence of non-caseating granulomas in involved tissues. Depressed cellular immunity predisposes patients to infections with certain intracellular organisms, mostly fungi, <it>Mycobacterium tuberculosis </it>and <it>Nocardia </it>species. As these infections are mainly insidious and difficult to differentiate from the underlying disease, a possible misdiagnosis may lead to fatal complications for the patient.</p> <p>Case presentation</p> <p>We present a case of a 67-year-old woman with undiagnosed asymptomatic stage I sarcoidosis for at least 8 years before her admission and a 1-month history of fever, exertional dyspnea and dry cough, in whom pulmonary tuberculosis was documented.</p> <p>Conclusion</p> <p>This case highlights the need for great vigilance among physicians in order to rule out any possible infection before establishing the diagnosis of sarcoidosis.</p
Reticular Chemistry at Its Best: Directed Assembly of Hexagonal Building Units into the Awaited Metal-Organic Framework with the Intricate Polybenzene Topology, pbz-MOF
Reticular Synthesis of HKUST-like tbo-MOFs with Enhanced CH<sub>4</sub> Storage
Successful implementation of reticular
chemistry using a judiciously
designed rigid octatopic carboxylate organic linker allowed the construction
of expanded HKUST-1-like <b>tbo</b>-MOF series with intrinsic
strong CH<sub>4</sub> adsorption sites. The Cu-analogue displayed
a concomitant enhancement of the gravimetric and volumetric surface
area with the highest reported CH<sub>4</sub> uptake among the <b>tbo</b> family, comparable to the best performing metal organic
frameworks (MOFs) for CH<sub>4</sub> storage. The corresponding gravimetric
(BET) and volumetric surface areas of 3971 m<sup>2</sup> g<sup>–1</sup> and 2363 m<sup>2</sup> cm<sup>–3</sup> represent an increase
of 115% and 47%, respectively, in comparison to the corresponding
values for the prototypical HKUST-1 (<b>tbo</b>-MOF-1), and
are 42% and 20% higher than that of <b>tbo</b>-MOF-2. High-pressure
methane adsorption isotherms revealed a high total gravimetric and
volumetric CH<sub>4</sub> uptakes, reaching 372 cm<sup>3</sup> (STP)
g<sup>–1</sup> and 221 cm<sup>3</sup> (STP) cm<sup>–3</sup>, respectively, at 85 bar and 298 K. The corresponding working capacities
between 5 and 80 bar were found to be 294 cm<sup>3</sup> (STP) g<sup>–1</sup> and 175 cm<sup>3</sup> (STP) cm<sup>–3</sup> and are placed among the best performing MOFs for CH<sub>4</sub> storage particularly at relatively low temperature. To gain insight
on the mechanism accounting for the resultant enhanced CH<sub>4</sub> storage capacity, molecular simulation study was performed and revealed
the presence of very strong CH<sub>4</sub> adsorption sites near the
organic linker with similar adsorption energetics as the open metal
sites. The present findings support the potential of <b>tbo</b>-MOFs based on the supermolecular building layer (SBL) approach as
an ideal platform to further enhance the CH<sub>4</sub> storage capacity
via expansion and functionalization of the quadrangular pillars
Reticular Chemistry at Its Best: Directed Assembly of Hexagonal Building Units into the Awaited Metal-Organic Framework with the Intricate Polybenzene Topology, pbz-MOF
The ability to direct the assembly
of hexagonal building units
offers great prospective to construct the awaited and looked-for hypothetical
polybenzene (<b>pbz</b>) or “cubic graphite” structure,
described 70 years ago. Here, we demonstrate the successful use of
reticular chemistry as an appropriate strategy for the design and
deliberate construction of a zirconium-based metal–organic
framework (MOF) with the intricate <b>pbz</b> underlying net
topology. The judicious selection of the perquisite hexagonal building
units, six connected organic and inorganic building blocks, allowed
the formation of the <b>pbz</b>-MOF-1, the first example of
a ZrÂ(IV)-based MOF with <b>pbz</b> topology. Prominently, <b>pbz</b>-MOF-1 is highly porous, with associated pore size and
pore volume of 13 Å and 0.99 cm<sup>3</sup> g<sup>–1</sup>, respectively, and offers high gravimetric and volumetric methane
storage capacities (0.23 g g<sup>–1</sup> and 210.4 cm<sup>3</sup> (STP) cm<sup>–3</sup> at 80 bar). Notably, the <b>pbz</b>-MOF-1 pore system permits the attainment of one of the
highest CH<sub>4</sub> adsorbed phase density enhancements at high
pressures (0.15 and 0.21 g cm<sup>–3</sup> at 35 and 65 bar,
respectively) as compared to benchmark microporous MOFs
Reticular Chemistry and the Discovery of a New Family of Rare Earth (4, 8)-Connected Metal-Organic Frameworks with <b>csq</b> Topology Based on RE<sub>4</sub>(μ<sub>3</sub>‑O)<sub>2</sub>(COO)<sub>8</sub> Clusters
In recent years, the design and discovery
of new metal-organic framework (MOF) platforms with distinct structural
features and tunable chemical composition has remarkably enhanced
by applying reticular chemistry rules and the molecular building block
(MBB) approach. We targeted the synthesis of new rare earth (RE)-MOF
platforms based on a rectangular-shaped 4-c linker, acting as a rigid
organic MBB. Accordingly, we designed and synthesized the organic
ligand 1,2,4,5-tetrakisÂ(4-carboxyphenyl)-3,6-dimethyl-benzene (H<sub>4</sub><b>L</b>), in which the two methyl groups attached to
the central phenyl ring lock the four peripheral carboxyphenyl groups
to an orthogonal/vertical position. We report here a new family of
RE-MOFs featuring the novel inorganic building unit, RE<sub>4</sub>(ÎĽ<sub>3</sub>-O)<sub>2</sub> (RE: Y<sup>3+</sup>, Tb<sup>3+</sup>, Dy<sup>3+</sup>, Ho<sup>3+</sup>, Er<sup>3+</sup>, and Yb<sup>3+</sup>), with planar <i>D</i><sub>2<i>h</i></sub> symmetry.
The rigid 4-c linker, H<sub>4</sub><b>L</b>, directs the in
situ assembly of the unique 8-c RE<sub>4</sub>(ÎĽ<sub>3</sub>-O)<sub>2</sub>(COO)<sub>8</sub> cluster, resulting in the formation
of the first (4, 8)-c RE-MOFs with <b>csq</b> topology, RE-<b>csq</b>-MOF-1. The structures of the yttrium (Y-<b>csq</b>-MOF-1) and holmium (Ho-<b>csq</b>-MOF-1) analogues were determined
by single-crystal X-ray diffraction analysis. Y-<b>csq</b>-MOF-1
was successfully activated and tested for Xe/Kr separation. The results
show that Y-<b>csq</b>-MOF-1 has high isosteric heat of adsorption
for Xe (33.8 kJ mol<sup>–1</sup>), with high Xe/Kr selectivity
(IAST 12.1, Henry 12.9) and good Xe uptake (1.94 mmol g<sup>–1</sup> at 298 K and 1 bar), placing this MOF among the top-performing adsorbents
for Xe/Kr separation