Endoscopic management of ureteral calculus in a patient with ureterosigmoidostomy diversion.

Lithiasis after urinary diversion is an uncommon condition that poses therapeutic challenges. The authors report the case of a patient submitted to cystectomy and ureterosigmoidostomy 35 years ago due to bladder endometriosis. The patient presented with a ureteral stone and was treated by retrograde endoscopic extraction.

Cavitand-functionalized SWCNTs for N-methylammonium detection.

Single-walled carbon nanotubes (SWCNTs) have been functionalized with highly selective tetraphosphonate cavitand receptors. The binding of charged N-methylammonium species to the functionalized SWCNTs was analyzed by X-ray photoelectron spectroscopy and confirmed by (31)P MAS NMR spectroscopy. The cavitand-functionalized SWCNTs were shown to function as chemiresistive sensory materials for the detection of sarcosine and its ethyl ester hydrochloride in water with high selectivity at concentrations as low as 0.02 mM. Exposure to sarcosine and its derivative resulted in an increased conductance, in contrast to a decreased conductance response observed for potential interferents such as the structurally related glycine ethyl ester hydrochloride.

Nanomechanical recognition of N-methylammonium salts.

Turning molecular recognition into an effective mechanical response is critical for many applications ranging from molecular motors and responsive materials to sensors. Herein, we demonstrate how the energy of the molecular recognition between a supramolecular host and small alkylammonium salts can be harnessed to perform a nanomechanical task in a univocal way. Nanomechanical Si microcantilevers (MCs) functionalized by a film of tetra-phosphonate cavitands were employed to screen as guests the compounds of the butylammonium chloride series 1-4, which comprises a range of low molecular weight (LMW) molecules (molecular mass < 150 Da) that differ from each other by one or a few N-methyl groups (molecular mass 15 Da). The cavitand surface recognition of each individual guest drove a specific MC bending (from a few to several tens of nanometer), disclosing a direct, label-free, and real-time mean to sort them. The complexation preferences of tetraphosphonate cavitands toward ammonium chloride guests 1-4 were independently assessed by isothermal titration calorimetry. Both direct and displacement binding experiments concurred to define the following binding order in the alkylammonium series: 2 > 3 ≈ 1 ≫ 4. This trend is consistent with the number of interactions established by each guest with the host. The complementary ITC experiments showed that the host-guest complexation affinity in solution is transferred to the MC bending. These findings were benchmarked by implementing cavitand-functionalized MCs to discriminate sarcosine from glycine in water.

Guest-controlled aggregation of cavitand gold nanoparticles and N-methyl pyridinium-terminated PEG.

The introduction of a disulfide functionalized tetraphosphonate cavitand on Au nanoparticles promotes the reversible self-assembly of a hybrid network upon addition of a polymeric ditopic guest.

Endoscopic management of ureteral calculus in a patient with ureterosigmoidostomy diversion

Lithiasis after urinary diversion is an uncommon condition that poses therapeutic challenges. The authors report the case of a patient submitted to cystectomy and ureterosigmoidostomy 35 years ago due to bladder endometriosis. The patient presented with a ureteral stone and was treated by retrograde endoscopic extraction.