Hybrid Molecular Magnets with Lanthanide- and Countercation-Mediated Interfacial Electron Transfer between Phthalocyanine and Polyoxovanadate

A series of {V₁₂}-nuclearity polyoxovanadate cages covalently functionalized with one or sandwiched by two phthalocyaninato (Pc) lanthanide (Ln) moieties via V-O-Ln bonds were prepared and fully characterized for paramagnetic Ln = Sm^III-Er^III and diamagnetic Ln = Lu^III, including Y^III. The LnPc-functionalized {V₁₂O₃₂} cages with fully oxidized vanadium centers in the ground state were isolated as (nBu₄N)₃[HV₁₂O₃₂Cl(LnPc)] and (nBu₄N)₂[HV₁₂O₃₂Cl(LnPc)₂] compounds. As corroborated by a combined experimental (EPR, DC and AC SQUID, laser photolysis transient absorption spectroscopy, and electrochemistry) and computational (DFT, MD, and model Hamiltonian approach) methods, the compounds feature intra- and intermolecular electron transfer that is responsible for a partial reduction at V(3d) centers from V^V to V^IV in the solid state and at high sample concentrations. The effects are generally Ln dependent and are clearly demonstrated for the (nBu₄N)₃[HV₁₂O₃₂Cl(LnPc)] representative with Ln = Lu^III or Dy^III. Intramolecular charge transfer takes place for Ln = Lu^III and occurs from a Pc ligand via the Ln center to the {V₁₂O₃₂} core of the same molecule, whereas for Ln = Dy^III, only intermolecular charge transfer is allowed, which is realized from Pc in one molecule to the {V₁₂O₃₂} core of another molecule usually via the nBu₄N⁺ countercation. For all Ln but Dy^III, two of these phenomena may be present in different proportions. Besides, it is demonstrated that (nBu₄N)₃[HV₁₂O₃₂Cl(DyPc)] is a field-induced single molecule magnet with a maximal relaxation time of the order 10^-3 s. The obtained results open up the way to further exploration and fine-tuning of these three modular molecular nanocomposites regarding tailoring and control of their Ln-dependent charge-separated states (induced by intramolecular transfer) and relaxation dynamics as well as of electron hopping between molecules. This should enable us to realize ultra-sensitive polyoxometalate powered quasi-superconductors, sensors, and data storage/processing materials for quantum technologies and neuromorphic computing.

No correlation between multi-locus heterozygosity and fitness in the common buzzard despite heterozygote advantage for plumage colour

Correlations between heterozygosity and fitness are frequently found but rarely well understood. Fitness can be affected by single loci of large effect which correlate with neutral markers via linkage disequilibrium, or as a result of variation in genome-wide heterozygosity following inbreeding. We explored these alternatives in the common buzzard, a raptor species in which three colour morphs differ in their lifetime reproductive success. Using 18 polymorphic microsatellite loci, we evaluated potential genetic differences among the morphs which may lead to subpopulation structuring and tested for correlations between three fitness-related traits and heterozygosity, both genome wide and at each locus separately. Despite their assortative mating pattern, the buzzard morphs were found to be genetically undifferentiated. Multilocus heterozygosity was only found to be correlated with a single fitness-related trait, infection with the blood parasite, Leucocytozoon buteonis, and this was via interactions with vole abundance and age. One locus also showed a significant relationship with blood parasite infection and ectoparasite infestation. The vicinity of this locus contains two genes, one of which is potentially implicated in the immune system of birds. We conclude that genome-wide heterozygosity is unlikely to be a major determinant of parasite burden and body condition in the polymorphic common buzzard.

Treatment of facial palsies with external eyelid weights

PURPOSE

Because ocular exposure is a major complication of facial paralysis, an external gold eyelid load weight was evaluated for effectiveness in the treatment of this problem.

METHODS

We prospectively studied 12 patients with unilateral facial paralysis who were treated with the external eyelid weights. Follow-up examinations included corneal exposure, amount of artificial tear usage, patient comfort, and complications associated with the weights. Treatment end points were the patient's decision to undergo a canthoplasty or placement of an implanted weight or resolution of the facial paresis to better than House's grade IV/VI.

RESULTS

Of the 12 patients studied, ten had decreased corneal exposure on the affected side, with a coincident decrease in artificial tear drop use and increased comfort. One patient had no improvement in a corneal defect, and one was unable to apply the weight. Five patients had some difficulty in positioning the weight, which was related to upper eyelid dermatochalasis in four of the five. Only two weights were lost in over two years of total wearing time.

CONCLUSIONS

External eyelid weights are useful in the treatment of ocular exposure associated with facial paralysis. The weights decreased corneal exposure, decreased reliance on artificial tear drops, and increased patient comfort. The weights were helpful as a trial before implantation of eyelid weights and as a longer-term treatment for ocular exposure in patients with temporary facial paralysis. Loose upper eyelid skin may limit their usefulness in some patients.

Congenital absence of the lacrimal puncta

We report seven cases of congenital absence of the lacrimal puncta, a condition that may be either an isolated finding or associated with other developmental anomalies. General pediatric evaluation of two patients with punctal agenesis revealed no additional abnormalities; these cases were managed by probing and silicone intubation. The other five cases were associated with other significant, clinically obvious abnormalities; several of these patients required more aggressive management of their lacrimal disorders, including dacryocystorhinostomy and conjunctivo-dacryocystorhinostomy. Previous reports support the impression generated by this series that otherwise normal appearing children with congenital absence of the lacrimal puncta do not require an extensive work-up. Probably many children with absent puncta are asymptomatic and remain undiagnosed.

Etiology and management of facial palsy

Palsy of the facial nerve can result in severe debilitation. The physical disfigurement has a disastrous effect on self-image. Asymmetry of facial expression, drooling, and difficulty with speech may occur. Additionally, impaired closure of the eye can result in exposure of the cornea with not only discomfort, but also loss of vision. If the nerve injury is proximal, loss of salivation, lacrimation, and changes in taste can occur. Clearly, an understanding of facial palsy and a framework for management are needed by the clinician who encounters this condition. The recent literature is surveyed for various causes of seventh nerve palsy and for therapeutic modalities available to the physician.

Hydatid disease in a horse

During routine necropsy of a 28-year-old horse with intestinal volvulus, numerous hydatid cysts were discovered in the liver. Viable protoscolices of Echinococcus granulosus were obtained from the cyst. As a 4-year-old, this horse had been imported from an area that is enzootic for equine hydatidosis.