Hyperbranched Polyglycerol‐Grafted Superparamagnetic Iron Oxide Nanoparticles: Synthesis,Characterization, Functionalization,Size Separation,Magnetic Properties,and Biological Applications

For biomedical application of nanoparticles, the surface chemical functionality is very important to impart additional functions, such as solubility and stability in a physiological environment, and targeting specificity as an imaging probe and a drug carrier. Although polyethylene glycol (PEG) has been used extensively, here, it is proposed that hyperbranched polyglycerol (PG) is a good or even better alternative to PEG. Superparamagnetic iron oxide nanoparticles (SPIONs) prepared using a polyol method are directly functionalized with PG through ring‐opening polymerization of glycidol. The resulting SPION‐PG is highly soluble in pure water (>40 mg mL^?1) and in a phosphate buffer solution (>25 mg mL^?1). Such high solubility enables separation of SPION‐PG according to size using size exclusion chromatography (SEC). The size‐separated SPION‐PG shows a gradual increase in transverse relaxivity (r₂) with increasing particle size. For biological application, SPION‐PG is functionalized through multistep organic transformations (–OH → –OTs (tosylate) → –N₃ → –RGD) including click chemistry as a key step to impart targeting specificity by immobilization of cyclic RGD peptide (Arg‐Gly‐Asp‐D ‐Tyr‐Lys) on the surface. The targeting effect is demonstrated by the cell experiments; SPION‐PG‐RGD is taken up by the cells overexpressing α_vβ₃‐integrin such as U87MG and A549.     

Preparation of hybrid films of aluminosilicate nanofiber and conjugated polymer

We have demonstrated the preparation of hybrid films of aluminosilicate nanofiber (imogolite) and water-soluble poly(p-phenylene) (WS-PPP), which has sulfonate groups. The imogolite/WS-PPP hybrid gel could be prepared by mixing a solution of these two materials and subsequent centrifugation. The aluminol (AlOH) groups on the surface of imogolite would be protonated under acidic conditions to afford AlOH₂⁺ groups that can interact with sulfonate groups (SO₃^?) of WS-PPP. Based on this ionic interaction, a layer-by-layer (LBL) assembly was applied to fabricate the hybrid films of imogolite nanofibers and WS-PPP. The deposited amounts of WS-PPP and imogolite were measured by quartz crystal microbalance (QCM) measurements and scanning electron microscopy (SEM) observation. Atomic force microscopy (AFM) observation revealed that imogolite nanofibers were well networked in the LBL hybrid film.     

Highly Enantioselective Cyclopropanation with Co(II)‐Salen Complexes: Control of cis‐ and trans‐Selectivity by Rational Ligand‐Design

Cyclopropanation of styrene derivatives with alkyl α‐diazoacetate in the presence of the second‐generation (salen)cobalt(II) complex 6 proceeded with excellent cis‐ and enantioselectivity. On the other hand, the cyclopropanation in the presence of complex 14 which was designed on the basis of the mechanism of asymmetric induction by complex 6 showed good trans‐ and excellent enantioselectivity.     

Fluorescence correlation spectroscopy excited with a stationary interference pattern for capillary electrophoresis

Using a combination of capillary electrophoresis (CE) and patterned fluorescence correlation spectroscopy (patterned FCS), we have developed a new technique for performing electrophoretic analysis independently of the initial length of injected analyte plugs. In t histechnique, which is abbreviated as CE/patterned FCS, fluorescent analyte molecules dispersed continuously in a capillary migrate through a stationary interference pattern created by two intersecting excitation laser beams, and their fluorescence emission is monitored. We prove theoretically that the power spectrum of fluctuations in the fluorescence intensity gives a virtual electropherogram. The profile of the electropherogram and the number of theoretical plates are in general obtained by using analytical methods. Characterizing the capillary length within the excitation beams as the effective length, we compare CE/ patterned FCS with conventional CE. Numerical simulations on capillary gel electrophoresis of DNA predict that the optimized CE/patterned FCS is superior to conventional CE when the effective length is shorter than 1 cm. The experimental feasibility of this technique is demonstrated in the fluorometry of TOTO-1-stained DNA. For an effective length of 740 microm, a maximum number of plates of 7400, and a resolution of 1.0 were obtained with a one-component injection of pUC18 DNA and a two-component injection of pUC 18 DNA and lambda DNA, respectively.     

Cathode-follower RF system for proton synchrotron and compressorrings

A model RF system with a cathode-follower was tested in its two operational modes without beam. One was for a synchrotron, where the frequency was modulated at 40 Hz; the other was for a compressor ring, where a barrier bucket was generated. Contrary to a simple theory on the inherent instability of the cathode-follower, the RF generation was quite stable in a wide frequency range     

System for coil simulation measurements of losses and instabilities in superconducting wires

A new system for measuring ac losses in superconductors under coil simulation conditions is described. It is aimed to investigate instabilities in local points of a coil. Currents up to 150 A and magnetic fields up to 0.4 T can be applied simultaneously and can be varied independently. The magnetic and electric fields on both sides of the sample are measured by means of pick-up coils and potential leads, respectively. By this method the instantaneous values of the power introduced through each of both sample surfaces can be measured separately. The validity of the method and the performance of the system are demonstrated by measuring the losses of a copper-clad single-core Nb-Ti-Zr wire for several values of the ratio between the current and the magnetic field, which are inphase.     

An autopsy case of renal failure as its cause of death in a patient with primary hyperparathyroidism associated with chronic pancreatitis

This paper presents a 59-year-old man who was admitted to our hospital because of abdominal pains in 1973. He had pancreatic calcification and showed high levels of serum amylase, Ca, and PTH. He was diagnosed as primary hyperparathyroidism with chronic pancreatitis. After excision of an ectopic parathyroid adenoma, serum Ca levels were decreased and normalized by dihydrotachysterol p.o. At the same time his symptoms disappeared. The exocrine and endocrine pancreatic functions, however, decreased gradually. Diabetes mellitus appeared in 1975 and he required insulin injection since 1983. In spite of the treatment, his diabetic control was poor. Seventeen years later in 1992, he showed hypertension and edema (nephrotic syndrome). Because of renal failure, he underwent hemodialysis and passed away due to myocardial infarction in 1993. Autopsy findings showed existence of diabetic nephropathy as the cause of renal failure. Clinical course of this patient suggests that severe complications occur even in pancreatic diabetes and that we have to control diabetes strictly in pancreatic diabetes as well as in primary diabetes.     

A tobacco protein kinase, NPK2, has a domain homologous to a domain found in activators of mitogen-activated protein kinases (MAPKKs)

A cDNA (cNPK2) that encodes a protein of 518 amino acids was isolated from a library prepared from poly(A)+ RNAs of tobacco cells in suspension culture. The N-terminal half of the predicted NPK2 protein is similar in amino acid sequence to the catalytic domains of kinases that activate mitogen-activated protein kinases (designated here MAPKKs) from various animals and to those of yeast homologs of MAPKKs. The N-terminal domain of NPK2 was produced as a fusion protein in Escherichia coli, and the purified fusion protein was found to be capable of autophosphorylation of threonine and serine residues. These results indicate that the N-terminal domain of NPK2 has activity of a serine/threonine protein kinase. Southern blot analysis showed that genomic DNAs from various plant species, including Arabidopsis thaliana and sweet potato, hybridized strongly with cNPK2, indicating that these plants also have genes that are closely related to the gene for NPK2. The structural similarity between the catalytic domain of NPK2 and those of MAPKKs and their homologs suggests that tobacco NPK2 corresponds to MAPKKs of other organisms. Given the existence of plant homologs of an MAP kinase and tobacco NPK1, which is structurally and functionally homologous to one of the activator kinases of yeast homologs of MAPKK (MAPKKKs), it seems likely that a signal transduction pathway mediated by a protein kinase cascade that is analogous to the MAP kinase cascades proposed in yeasts and animals, is also conserved in plants.