Synthesis, structure and unique reactivity of the ethylzinc derivative of a bicyclic guanidine.

An equimolar reaction between ZnEt(2) and 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine (hppH) results in the formation of EtZn(hpp) (1) which crystallizes as a trinuclear agglomerate with the guanidinate ligands spanning 4-coordinate Zn centers. Exposure of a pre-formed THF solution of 1 to undried air leads to a ZnO-incorporating derivative 1(4)·ZnO, while an analogous experiment with CH(2)Cl(2) as solvent leads to a novel tetranuclear mixed aggregate formulated as [EtOZn(hpp)](2)[ClZn(hpp)](2) (2). The composition of 2 indicates that its formation proceeds via a complex multi-step reaction route that involves not only the oxygenation of ZnEt moieties, but also the activation of CH(2)Cl(2), causing the transfer of a chloride anion to the Zn center. Compounds were characterized by (1)H NMR spectroscopy and single-crystal X-ray diffraction analysis.

Confined palladium colloids in mesoporous frameworks for carbon nanotube growth.

Palladium colloidal nanoparticles with an average size of approximately 2.4 nm have been incorporated into mesoporous inorganic thin films following a multistep approach. This involves the deposition of mesoporous titania thin films with a thickness of 200 nm by spin-coating on titanium plates with a superhydrophilic titania outer layer and activation by calcination in a vacuum furnace at 573 K. Nanoparticles have been confined within the porous titania network by dip-coating noble metal suspensions onto these mesoporous thin films. Finally, the resulting nanoconfined systems were used as substrates for the growth of oriented carbon nanotubes (CNTs) using plasma-enhanced chemical vapour deposition at 923 K in order to enhance their surface area. These CNTs were tested in the hydrogenation of phenylacetylene by hydrogen in a batch reactor. The initial reaction rate observed on a CNT/TiO2 structured catalyst was considerably higher than that on 1 wt% Pd/TiO2 thin films.

Advanced fine-tuning of grubbs/hoveyda olefin metathesis catalysts: a further step toward an optimum balance between antinomic properties.

A 95% yield in the cross metathesis of acrylonitrile with a model olefin is achieved at 25 degrees C with only 3 mol % of the new air-stable ruthenium catalyst 1f shown in the enclosed structural diagram. Even more remarkable are the performances of its boosted version 1g incorporating an electron-withdrawing group. Both these new enhanced versions of Hoveyda catalyst are readily available from Grubbs second generation precatalyst upon reaction with a styrenyl ether the end group of which has been functionalized by an ester function. The latter acts as a weakly coordinating ligand allowing to reach a desirable balance between antinomic properties such as the catalyst's stability, a high activity for challenging substrates, and a high initiation rate.

Disc arthroplasty in the lumbar and cervical spine.

Background. The authors present their own experiences with disc prosthesis procedures in the lumbar and cervical spine. Material and methods. The article presents an analysis of post op results in a series of 24 patients who underwent disc replacement surgery in the lumbar spine and 11 patients in whom a disc endoprosthesis was performed in the cervical spine. Average follow-up was 9.2 months. The authors paid particular attention to the pre-op and post-op patient symptoms. Functional assessment of the patients was performed with the Oswestry Low Back Pain Disability Index. Results and Conclusions. The obtained results seem to indicate that this procedure can yield excellent results in selected cases. The key to obtaining a good post-op result is careful selection of patients with "pure" discogenic low back pain.

[Surgical treatment of herniated intervertebral discs in children and teenagers]. / Leczenie operacyjne przepukliny jadra miazdzystego u dzieci i mlodziezy.

The authors present early results od surgical treatment of herniated intervertebral discs in children and teenagers. Five cases of herniated intervertebral discs in the lumbar spine in teenagers were treated surgically between 2000 and 2002. The paper presents early results of surgical treatment, as well as the indications for it. It is the authors' opinion that the indications for surgery of herniated lumbar discs among children and teenagers do not differ form indications among adults. Postponing surgery because of young age seems to be unjustified.

[Vertebroplasty in treatment of pathological fractures of the lumbar spine]. / Vertebroplastyka w leczeniu zlaman patologicznych kregoslupa.

The authors present the results of 6 cases of lumbar vertebroplasty in the treatment generalized neoplastic disease. In the analyzed group there were 4 females and 2 males (average age: 57 years). In all cases vertebroplasty was performed because of pathological fracture of vertebral bodies and consequent untreatable lumbar pain in. Pain was assessed directly before surgery, 5 days and 8 weeks post-op. using VAS (Visual Analog Scale) and the Oswestry Back Pain Disability Index. In 4 cases major pain relief was noted, while in 1 case moderate pain relief was noted and in 1 case pain symptoms remained unchanged after the procedure.

[Wartenberg's disease--superficial radial neuropathy. Case report]. / Choroba Wartenberga--neuropatia uciskowa galezi powierzchownej nerwu promieniowego--opis przypadku.

This paper describes a case of surgical treatment in 55 years old patient with superficial radial neuropathy.

[Surgical treatment of cubital tunnel syndrome]. / Leczenie operacyjne zespolu rowka nerwu lokciowego.

Review article the authors presents five surgical procedures to decompress the ulnar nerve at the elbow. The paper reviews biomechanical problems related to the surgical procedures. The literature was reviewed in order to systemic opinions concerning the operative procedures currently employed for surgery.

[Early results of surgical treatment of spondylolisthesis]. / Wczesne wyniki leczenia operacyjnego spondylolistezy.

Basing on a series of 49 patients (26 women and 23 men), the authors present the early results of surgical treatment of spondylolisthesis. The age of the patients ranged from 13 to 63 years (average age: 42.7 years). In the analyzed series 49 patients were over 20 years of age. Only 4 patients were less than 20 years of age. Surgery was performed in all cases at the Spine Surgery Unit of the W. Dega University Hospital in Poznan, Poland between 1999 and 2002. The authors also present the qualification criteria for surgery, as well as the surgical technique employed. Transpedicular fixation is the method of choice in cases non-responsive to conservative treatment.