Novel plasma biomarker surrogating cerebral amyloid deposition

Alzheimer’s disease (AD) is the most common and devastating dementia. Simple and practical biomarkers for AD are urgently required for accurate diagnosis and to facilitate the development of disease-modifying interventions. The subjects for the study were selected on the basis of PiB amyloid imaging by PET. Forty PiB-positive (PiB+) individuals, including cognitively healthy controls (HC), and mild cognitive impairment and AD individuals, and 22 PiB-negative (PiB−) HC participated. Employing our novel highly sensitive immunoprecipitation-mass spectrometry, we measured plasma amyloid β-proteins (Aβs; Aβ1-40 and Aβ1-42) and Aβ-approximate peptides (AβAPs), which were cleaved from amyloid precursor protein (APP). Among the AβAPs, APP669-711 appeared to be a good reference for deciphering pathological change of Aβ1-42. We evaluated the performance of the ratio of APP669-711 to Aβ1-42 (APP669-711/Aβ1-42) as a biomarker. APP669-711/Aβ1-42 significantly increased in the PiB+ groups. The sensitivity and specificity to discriminate PiB+ individuals from PiB− individuals were 0.925 and 0.955, respectively. Our plasma biomarker precisely surrogates cerebral amyloid deposition.     

Raman scattering in the depletion region of GaAs

We have obtained spectra for the LO phonon mode by Raman scattering associated with surface quantization of the hole states in the depletion layer of highly doped n-type GaAs samples. When semi-transparent metal contacts are employed, the zone-center LO peak shifts to higher frequency due to plasmon-phonon interaction. The observed effects are not sensitive to the types of metal. The presence of the plasmon mode is thought to be due to the steady-state carrier injection from the incident laser light. The position of the peak is used to estimate the surface recombination rate of the excited electron-hole pairs.     

Interlaboratory comparison of actinides in human tissue239Pu and240Pu

An international laboratory intercomparison of actinides in human tissues was organized by the United States Transuranium Registry and the National Institute of Standards and Technology. Five laboratories from the United States, United Kingdom, and Japan participated in the intercomparison. The laboratories were requested to analyze Standard Reference Materials 4351 (Human Lung) and 4352 (Human Liver) for²³⁹Pu and²⁴⁰Pu concentration. Approximately equivalent measurement capabilities were generally found among the participants. The results of this intercomparison were statistically comparable to those used for the original certification of the SRM's and were combined for a re-evaluation of the certified values. The combined data sets provide a better characterization of the inhomogeneity of these reference materials and result in a better basis for certification.Deceased.     

Magnetically Alignable Bicelles with Unprecedented Stability Using Tunable Surfactants Derived from Cholic Acid

Five novel surfactants were prepared by modifying the three hydroxy groups of sodium cholate with triethylene glycol chains endcapped with an amide ( SC‐C₁ , SC‐ ⁿ C₄ , and SC‐ ⁿ C₅ ) or a carbamoyl group ( SC‐O ⁿ C₄ and SC‐O ^t C₄ ). The phase behavior of aqueous mixtures of these surfactants with 1,2‐dimyristoyl‐sn‐glycero‐3‐phosphatidylcholine (DMPC) was systematically studied by ³¹P NMR spectroscopy. The surfactants endcapped with carbamate groups ( SC‐O ⁿ C₄ and SC‐O ^t C₄ ) formed magnetically alignable bicelles over unprecedentedly wide ranges of conditions, in terms of temperature (from 21–23 to >90 °C), lipid/surfactant ratio (from 5 to 8), total lipid content (5–20 wt %), and lipid type [DMPC, 1,2‐dilauroyl‐sn‐glycero‐3‐phosphatidylcholine (DLPC), or 1‐palmitoyl‐2‐oleoyl‐sn‐glycero‐3‐phosphatidylcholine (POPC)]. In conjunction with appropriate phospholipids, the carbamate‐endcapped surfactants afforded unique bicelles, characterized by exceptional thermal stabilities (from 0 to >90 °C), biomimetic lipid compositions (DMPC/POPC=25:75 to 50:50), and extremely large ²H quadrupole splittings (up to 71 Hz).     

Radical polymerisation of styrene in porous coordination polymers

The first radical polymerisation of styrene in porous coordination polymers has been carried out, providing stable propagating radicals (living radicals), and a specific space effect of the host frameworks on the monomer reactivity is demonstrated.